Training Doc Mercedes 900

Training Documentation Mercedes-Benz Industrial Engines Series 500, 460 und 900

MTU Trainingcenter © MTU Friedrichshafen GmbH | All rights reserved

Table Of Contents

Information

Page 8

Tightening specifications

Page 9

Safty information

Page 18

Mercedes-Benz Engine Data Manual

Page 21

Mercedes-Benz Fluid and lubricant specification

Page 22

Emission standards

Page 23

Series 500 engine models

Page 24

Technical features

Page 26

Engine cross section

Page 27

Cylinder designation

Page 29

Cylinder head and gasket

Page 30

Valve drive

Page 36

Injection system

Page 39

Nozzle holder kombination removal and installation

Page 41

Unit pump removal and installation

Page 43

Piston

Page 46

Page 2

© MTU Friedrichshafen GmbH | All rights reserved

Table Of Contents

Piston cooling

Page 48

Connecting rod

Page 50

Crankcase

Page 51

Cylinder liner

Page 52

Fuel system

Page 55

Fuel filter removal and installation

Page 57

Fuel pre-filter

Page 58

Oil cooler and filter housing

Page 62

Components of the lubricating system

Page 64

Engine oil and filter change

Page 67

Crankcase ventilation system

Page 69

Coolant distribution

Page 72

Thermostat

Page 73

Air and exhaust ducting

Page 74

Assessment cylinder liners

Page 77

Page 3


Table Of Contents Series 460

Page 84

Technical features

Page 86


Page 87


Page 89


Page 90

Valve drive

Page 30 and 91

Injection system

Page 94


Page 39


Page 41

Piston

Page 43

Piston cooling

Page 46

Connecting rod

Page 97

Crankcase

Page 98

Cylinder liner

Page 99

Fuel system

Page 101


Page 57

Fuel pre-filter

Page 58

Page 4


Table Of Contents Oil cooler and filter housing

Page 105


Page 107


Page 67


Page 69

Thermostat

Page 111


Page 112


Page 77

Series 900 engine models

Page 114

Technical features

Page 116


Page 117


Page 119


Page 120

Valve drive

Page 125

Injection system

Page 128


Page 130


Page 132

Piston

Page 135

Page 5


Table Of Contents Piston cooling

Page 136

Connecting rod

Page 137

Crankcase

Page 138

Cylinder liner

Page 139

Fuel system

Page 141


Page 144

Fuel pre-filter

Page 58

Oil cooler and filter housing

Page 147


Page 149


Page 151


Page 153

Thermostat

Page 155


Page 157


Page 77

Page 6


Table Of Contents Engine electronic – controller (MR)

Page 157

Structure and priciple

Page 158

Injection control

Page 161

Delivery phases of the unit pump

Page 163

Sensor overview series 500

Page 166


Page 170


Page 173

Sensors

Page 178

Rotational speed, crank angle and TDC detection

Page 179

Rotary sensor

Page 180

Temperature sensor characteristic

Page 181

Oil level sensor

Page 182

Control loop (MR)

Page 184

Parameterization

Page 185

Minidiag 2

Page 186

Engine Tests

Page 187

ADM-X

Page 188

Special tools

Page 192

Page 7


Information

This documentation is for training purposes only. All torques and procedures reflect the stand of now and have to be validated bevore use. This Publication is protected by copyright and may not be used in any way whether in whole or in part without the prior written permission of MTU Friedrichshafen GmbH. This restriction also applies to copyright, distribution, translation, microfilming and storage or processing on electronic systems including data bases and online services.

1.Edition

10.2010

Page 8


Tightening specification for set screw and stud connections Tightening specification for set screw and stud connections to works standard MTN 5008 This works standard applies to set screws subjected to little dynamic load as per MMN 384, DIN 912, EN 24014 (DIN 931–1), EN 24017 (DIN 933), EN 28765 (DIN 960), EN 28676 (DIN 961), DIN 6912 and to studs as per DIN 833, DIN 835, DIN 836, DIN 938, DIN 939 and associated nuts. They do not apply to heat-proof screws in the hot component area. Tightening torques MA are for screws of strength class 8.8 (bright surface, phosphate coating or galvanised) and 10.9 (bright surface or with phosphate coating). The values in the table are based on a friction coefficient μtot = 0.125. Precondition: Thread and mating faces of screws and nuts must be coated in engine oil prior to assembly. When tightening manually (tightening specifications), an assembly tolerance of + 10% of the table values is permitted for unavoidable deviations of the tightening torque from the table value during the tightening process – e.g. resulting from inaccurate readings and overtightening during assembly. When tightening mechanically, the permitted assembly tolerance is + 15 % Tightening torques = MA

Page 9


Tightening specification for set screw and stud connections

Page 10


Tightening specification for set screw and stud connections

Page 11


Tightening torques for plugs

Tightening torques for plugs prescribed in standard MTN 5183–1 This standard applies to plugs as per DIN 908, DIN 910 and DIN 7604 with screwed plug DIN 3852, model A (sealed by sealing ring DIN 7603–Cu). DIN 908 DIN 910 DIN 7604A/C Tightening torques MA are given for plugs made of steel (St) with surface protected by a phosphate coating and oiled or galvanised. Thread and mating faces beneath heads must be coated in engine oil prior to assembly. An assembly tolerance of + 10% of the table values is permitted for unavoidable deviations of the tightening torque from the table value during the tightening process – e.g. resulting from inaccurate readings and overtightening during assembly. Tightening torques = MA

Page 12



Page 13



Page 14


Tightening torques for banjo screws

This standard applies to banjo screws as per MMN 223 and N 15011 sealed with sealing ring DIN 7603-Cu Tightening torques MA are given for banjo screws made of steel (St) with surface protected by a phosphate coating and oiled or galvanised and for banjo screws made of copper-aluminium alloys. Thread and mating faces beneath heads must be coated in engine oil prior to assembly. An assembly tolerance of + 10% of the table values is permitted for unavoidable deviations of the tightening torque from the table value during the tightening process – e.g. resulting from inaccurate readings and overtightening during assembly. Tightening torques = MA

Page 15


Tightening torques for banjo screws

Page 16


Torque specifications for union nuts Torque specifications for union nuts as per DIN 3859-2

1 Union nut 2 Union body 3 O-ring 4 Ball bushing

Union nut: When installing the ball bushing, the union nut should be tightened firmly by hand (noticeable increase in force) a quarter of a turn (90°) beyond this point.

Page 17


Safety Instructions These Safety Instructions must be read and followed by any persons operating, carrying out maintenance or repairs on the machinery plant. General Safety and Accident Prevention Regulations In addition to the instructions in this publication, general safety and accident prevention regulations and laws must be taken into consideration; these may vary from country to country. This MTU engine is a state-of-the-art product and conforms with all the applicable specifications and regulations. Nevertheless, persons and property may be at risk in the event of: – Incorrect use – Servicing, maintenance and repair carried out by untrained members of staff – Modifications or conversions – Non-compliance with the safety instructions Correct Use The engine is to be used solely for the purpose stated in the contract. Any other use is considered improper use. The manufacturer will accept no liability for any resultant damage. The responsibility is borne by the user alone. Correct use also includes observation of the Operating Instructions and Maintenance Manual and compliance with maintenance and repair instructions. Personnel Requirements Work on the engine must be carried out only by reliable personnel. The specified legal minimum age must be respected. Only fully trained or qualified personnel must be employed. Responsibilities of the operating, maintenance and repair personnel must be specified. Modifications or Conversions Modifications made by the customer to the engine may affect safety. No modifications or conversions must be implemented without prior consent from DDC or MTU. We cannot accept liability for any damage resulting from unauthorised alterations made to the engine. Organisational Measures The personnel must be instructed on engine operation and repair by means of the Maintenance Manual, and in particular the safety instructions must be explained. This is especially important for personnel who work on the engine only on an occasional basis.

Page 18


Safety Instructions Spare Parts Spare parts must at least satisfy the requirements specified by the manufacturer. This is guaranteed when original components are used. Working Clothes and Protective Equipment Always wear protective shoes when working on plant. Select appropriate goggles for the work to be carried out. Always wear protective goggles when working with mallets, cutting tools, drift punches and similar tools. Work clothing must be tight-fitting so that it does not catch on rotating or projecting components. Do not wear jewellery (e.g. rings, chains, etc.). Transport Lift the engine only with the lifting eyes provided. Use only the transport and lifting equipment approved by DDC/MTU. The engine must only be transported in installation position. Engine Operation When the engine is running, ear protectors must always be worn in the engine room.The engine room must be well ventilated. To avoid injuries caused by falling, leaked or spilt engine oil and coolant must be cleaned up immediately or absorbed with appropriate bonding agents. Exhaust gases from combustion engines are poisonous and injurious to health if inhaled. The exhaust pipework must be leak-free and discharge exhaust gases to atmosphere. During engine operation, do not touch battery terminals, generator terminals or cables. Inadequate protection of electrical components can lead to electric shocks and serious injuries. Never disconnect coolant, oil, fuel, compressed air or hydraulic lines while the engine is running. Maintenance and Repair Compliance with maintenance and repair specifications is an important safety factor. Unless expressly permitted, no maintenance or repair work must be carried out with the engine running. The engine must be secured against inadvertent starting and the battery disconnected. Attach sign “Do not operate” in operating area or to control equipment. Persons not involved must keep clear. Never attempt to rectify faults or carry out repairs if you do not have the necessary experience or special tools required. Maintenance work must only be carried out by authorised, qualified personnel. Use only tools in perfect condition. Do not work on engines or components which are only held by lifting equipment or crane. Always support these components on suitable frames or stands before beginning any maintenance or repair work. Before barring the engine, ensure that nobody is within the danger area. After working on the engine, check that all guards have been reinstalled and that all tools and loose components have been removed from the engine. Fluids emerging under high pressure can penetrate clothing and skin and may cause serious injury. Before starting work, relieve pressure in systems and H.P. lines which are to be opened. Never bend a fuel line and do not install bent lines. Keep fuel injection lines and connections clean. Always seal connections with caps or covers if a line is removed or opened.

Page 19


Safety Instructions During maintenance or repair work, do not hit fuel lines with wrenches or other tools. To tighten connections when installing lines, use the correct tightening torque and ensure that all retainers and dampers are installed correctly. Ensure that all fuel injection lines and compressed oil lines have sufficient play to avoid contact with other components. Do not place fuel or oil lines near hot components. Do not bend lines under pressure or use force. In order to avoid burning, take special care when placing hot components on products when working with hot liquids in pipelines, pipes and chambers. Until the engine has cooled, the breather cap must not be opened. Release the breather cap and allow pressure to escape before removing the cap. Take special care when removing ventilation or plugs from engine. In order to avoid being sprayed with highly pressurised liquids, hold a cloth over the screw or plug. It is even more dangerous if the engine has recently been shut down as the liquids may still be hot. Take special care when draining hot fluids – risk of injury. Drain the fluids into a suitable container and wipe up any spillages. When changing engine oil or working on the fuel system, ensure that the engine room is adequately ventilated. When working high on the engine, always use suitable ladders and work platforms. Make sure components are placed on stable surfaces.To avoid damaging your back when lifting components weighing 25 kg (50 lb.) or more, use lifting gear or request aid from other workers. Ensure that all chains, hooks, slings, etc. are in good condition, are sufficiently strong and that hooks are correctly positioned. Lifting eyes must not be unevenly loaded. When operating electrical equipment, certain components of this equipment are live. Non-compliance with warning notices could result in serious physical injury or damage to property. Work must be carried out only by qualified personnel. Prior to working on electrical equipment, switch off live units. Gases released from the battery are explosive. Avoid sparks and naked flames. Do not allow battery acids to come into contact with skin or clothing. Wear protective goggles. Do not place tools on the battery. Before connecting the cable to the battery, check battery polarity. Battery pole reversal may lead to injury through the sudden discharge of acid or bursting of the battery body. Do not damage wiring during removal work and when reinstalling wiring and ensure that during operation it is not damaged by contact with sharp objects, by rubbing against another component or by a hot surface. Never connect wiring to a line which carries liquid. On completion of the maintenance and repair work, any cables which have become loose must be correctly secured. Always tighten connectors with connector pliers. If cables are present at mechanical components and there is a risk of wear, the cables must be retained in cable clamps. For this purpose, no cable straps must be used as, during maintenance and/or repair work, the straps can be removed but not installed a second time. Check security of all plug-in connections. It is not sufficient to tighten the connections by hand with a bayonet union. There is the risk of the lock not engaging properly and the connector coming loose during engine operation. Therefore pliers must be used for turning the bayonet union nut in clockwise direction. Environmental Protection Dispose of used fluids and lubricants and filters in accordance with local regulations. Manipulation of the injection or control system can influence the engine performance and exhaust emissions. As a result, compliance with environmental regulations may no longer be guaranteed.

Page 20


Mercedes Benz Engine Data Manual

https://motorenhandbuch.i.daimler.com

Page 21


Mercedes-Benz Specifications for Operating Fluids

The MB BeVo provide you with an overview of not only the requirements for the operating fluids, but also for the recommended.

http://bevo.mercedes-benz.com/

Page 22


Emission Standards HDDE >130KW

Page 23


Series 500 Engine Models

Series 500 Baureihe

Page 24


V6

V8

OM 501 LA

OM 502 LA

VH = 12l

VH = 16l

OM 502 LA

Page 25


Technical Features Series 500                    

Outstanding power output and torque characteristics over the whole rpm range Dynamic start-off characteristics and pulling power Attractive power/weight ratio Low fuel consumption High-pressure direct injection, pump-line-nozzle system with peak pressures up to 1,800 bar. Electronic engine control (MR) with electronic system fixed to the engine, and extensive engine protection functions Direct injection with centrally positioned injection nozzle. 4-valve technology Useful engine brake rpm well over rated rpm, up to 2400 rpm Meets the emission legislation of Euromot IIIa Turbocharger with charge air cooling Rated engine speed 1,800 rpm or 2000 rpm Low maintenance requirement Long maintenance intervals Engine oil and fuel filter located at the front, for easy maintenance Maintenance-free belt drive Can run on FAME / RME (rape methyl ester) or biodiesel, and engine oil changes are halved High reliability and long runtime Low number of component variants, as many parts are the same on both 6 and 8 cylinder engines Rear engine power take-off ex works

Page 26


OM 502 LA Cross Section

Page 27



Page 28


Cylinder Designation

1

2

3

4

KGS

KS

5

Page 29


6

7

8

Cylinderhead

The Euromot IIIa engines are fitted with a modified cylinder head and therefore a new cylinder head gasket with increased elastomer thickness. The following bores in the base of the cylinder head have been provided with countersinks with a depth of 1.0 mm: • Engine oil pressure side (OD) • Engine oil return (OR) • Coolant supply (WZ) • Coolant return (WR)

Page 30


Cylinderhead Gasket

On the cylinder head gasket, the elastomer sealing elements at the following bores have been raised by the dimension (X): • Engine oil pressure side (OD) • Engine oil return (OR) • Coolant supply (WZ) • Coolant return (WR) The sealing between the cylinder head and the crankcase is improved because the elastomeric sealing elements are higher. Moreover, a fire shield (arrow) was vulcanized onto the coolant feed hole (WZ). This fire shield (arrow) is an added protection for the elastomeric sealing element in the event of a possible minor gas leak in the cylinder head gasket.

OD Engine oil pressure side OR Engine oil return WR Coolant return WZ Coolant feed X Dimension

Page 31


Cylinder Head with Inductively-hardened Sealing Surface As of engine end no. 263.000, the cylinder heads have been modified. The cylinder head sealing surface has been inductively hardened at four points (arrows). This inductive hardening is visible by a slight increase in height at the four points (arrows). This increases the contact pressure on the cylinder head gasket. Repair information: Cylinder head sealing surfaces with the four inductively hardened points (arrows) may only be visually checked for flatness in the sections where there are no raised areas due to inductive hardening. The cylinder head generally has to be exchanged if there is any distortion to the cylinder head or wear to the cylinder head sealing surface caused by the beaded cylinder head gasket, otherwise a seal between the cylinder head and crankcase cannot be ensured. The cylinder head sealing surface may not be reworked (ground).

Page 32


Cylinder Head

Coolant Engine Oil Charge Air Exhaust Fuel Fuel Return / Leak Off

Page 33


Cylinder Head Mounting The cylinder head is tightened in 6 stages. The cylinder head bolts do not require retightening. Moisten the bolts with engine oil! 1. 2. 3. 4. 5. 6.

Stage Stage Stage Stage Stage Stage

10 Nm 50 Nm 100 Nm 200 Nm 90 ° 90 °

1

3

4

2

The maximum shank length of 212 mm is not to be exceeded !

L

Page 34


Notes

Page 35


Valve Drive Gas exchange is improved by 4-valve technology, thus contributing considerably to lower fuel consumption with lower emissions. The intake and exhaust valves are controlled by means of roller tappets, push rods and intake and exhaust rocker arms which are set in a groove in the crankcase with a sliding block, and which operate the intake/exhaust valve pairs through a valve bridge. The rocker arm spindle complete with preassembled rocker arms and rocker arm bearing bracket is bolted to the cylinder head. To keep wear in the whole valve assembly to a minimum throughout ist lifetime, the contact surfaces of the valve, valve bridge, the rocker arm thumb, the upset ball socket of the push rod, and the ball head of the adjusting screw, are induction hardened. This is to allow them to support the actuation forces of the high-temperature valve springs, and the effects of inertial forces and cylinder pressures.

Page 36


Valve Adjustment Checking valve clearance at two crankshaft positions 1. Check TDC position of piston in cylinder A1: If the rocker arms are not under load on cylinder A1, the piston is in firing TDC. If the rocker arms are under load on cylinder A1, the piston is in overlap TDC. 2. Check valve clearance with cold engine: • Inlet = 0.4 mm; • Exhaust = 0.6 mm; 3. Check all valve clearances at two crankshaft positions (firing and overlap TDC for cylinder A1) as per diagram. 4. Use feeler gauge to determine the distance between valve bridge and rocker arm. 5. If the deviation from the reference value exceeds + 0.2 mm / -0.1 mm, adjust valve clearance.

Page 37


Adjusting valve clearance 1. Loosen locknut (1) and unscrew adjusting screw (2) by a few threads. 2. Insert feeler gauge between valve bridge and rocker arm. 3. Readjust adjusting screw (2) so that the feeler gauge just passes through the gap. 4. Tighten locknut (1) to 50 Nm, holding adjusting screw (2) firmly. 5. Check if the feeler gauge just passes through between valve bridge and rocker arm. Result: If not, adjust valve clearance.

Notes

Page 38


Pump-Line-Nozzle Injection System (PLD)

The injection process is performed by the pump-linenozzle (PLD) system, controlled by an electronic engine management system In the PLD system, fuel is delivered to the injection nozzle by individual unit pumps over short, rigid high-pressure injection lines, and through the pressure pipe connection screwed into the cylinder head. The connection to the nozzle and nozzle holder is located centrally at the cylinder, and is integrated with, and removable from, the cylinder head. A unit pump fitted for each cylinder is located directly on the crankcase.

Page 39


Pressure Pipe Connection And Nozzle Holder Location 7 Connection to the nozzle holder and injection nozzle (positioned vertically at the center of the cylinder), is through a fixed, preassembled pressure pipe connection with integral pin-type filter.

6 1

2

3

4

The nozzle holder with injection nozzle is held in a protective sleeve by means of a clamping claw supported on the nozzle holder and constant throttle cap, and attached with a central screw. The seal at the nozzle protective sleeve consists of a copper sealing sleeve. For nozzle holder positioning, the clamping claw grips a locating pin fixed into the nozzle holder cap. The pressure pipe connection is attached with a press-in ball fastening.

Page 40


1 2 3 4 5 6 7 8 9

Injection line, 30 Nm Pressuer screw, 40 Nm O-Ring Pressure pipe connection Nozzle holder combination O-Ring Screw, 50 Nm,  91 mm Clamping claw Constant throttle cap

5

8

9

Removing The Nozzle Holder Combination Injector removal 1. Remove fuel leak line. 2. Remove fuel line (3). 3. Remove thrust screw (2). 4. Pull off pressure pipe neck (1). 5. Remove screw (4). 6. Take off clamp (5). 7. Screw impact extractor (6) into injector. 8. Remove injector using the impact extractor. 9. If necessary remove sealing sleeve with extractor (7) from cylinder head. 10. Seal all openings with appropriate covers after removal.

5

4

6 7

Page 41


Installing The Nozzle Holder Combination

1. 2. 3. 4. 5. 6. 7.

8.

Measure the shank length of screw (4) (max 91 mm) Insert a new O-ring at nozzle holder combination Press new sealing sleeve (8) with special tool (7) onto nozzle holder combination Install nozzle holder combination Mount the retaining clip (5), 50Nm Place the new O-ring at pressure pipe connection (1) Fit the pressure pipe connection (1) and tighten pressure screw (2),40 Nm. Moisten the pressure pipe connection around the taper seal with engine oil. Install the injection line (3)

5

4

7 8

Page 42


Injection Pump Removal

Injection pump removal 1. Disconnect wiring (1) from injection pump. 2. Remove fuel line (2). 3. Unscrew securing screws of injection pump by approx. 10 mm. The preloaded compression spring presses the injection pump out of the crankcase. If not use special tool (6)and carefully extract pump. 4. Remove injection pump securing screws. 5. Remove injection pump. 6. Remove sealing rings from injection pump. 7. Seal all openings with appropriate covers after removal.

6

Page 43


Injection Pump Installation Injection pump installation 1. 2.

3. 4. 5. 6. 7. 8.

Remove all covers from openings Coat the new o-rings with lubricating grease, and install them with tool (3). Note: The black o-ring must be allways on top! Carefully clear any dirt or paint residues away from the sealing surface of the MR/PLD unit pump and the crankcase. Carefully press the MR/PLD unit pump in by hand. If the unit pump cam is up at the camshaft, turn the engine. Install the bolts and tighten to 65Nm. Install injection line (2) and tighten to 30Nm. Connect wiring (1) (1,5 Nm). If pump has been changed, new pump code must be programed via the MiniDiag2.

3

Page 44


Notes

Page 45


Piston Pistons and piston rings are among the most highly stressed engine components. Pistons are therefore constructed of high-temperature aluminum alloy. The piston top land and stem are graphite-coated to increase runningin and limp-home capability. There is a cast-in, reinforced ring groove for the first piston ring. The piston pin support is trapezoidal in shape, to increase the pressure-load surfaces on the piston and connecting rod.

Features of the piston rings: Groove 1: Compression ring Cast-iron keystone ring with plasma spray layer of chromeceramic, spherical-lapped. Groove 2: Compression ring with oil-scraper action. Chrome-plated taper-faced ring with internal angle underneath. Groove 3: Oil scraper ring Roof bevel ring with chrome-plated, lapped lands and garter springs.

Page 46


Piston Changes For Euromot 3A New combustion process with W- Piston: - higher stability - less carbon build up

old

Page 47


new

Piston Cooling

Due to the piston's increased cooling requirements and additional camshaft oiling, the oil spray nozzle on the Euromot IIIa engine has a higher oil throughput. This also necessitates modifications to the oil pump. The spray direction of the oil spray nozzle for the piston has been changed to coaxial oil spraying, which sprays into the undivided, fluted cooling duct in the piston. Due to this modification, piston cooling is improved as a result of increased engine oil throughput. The oil spray nozzle's pipe diameter has been increased to 4 mm, and the diameter at the outlet aperture at the end of the nozzle has been calibrated to 3 mm. Due to this modification, the oil spray nozzle has a higher oil throughput, and the oil spray fans out less, leading to better piston cooling. The base of the oil spray nozzle has three bores (arrows) for oiling the intake, exhaust and unit pump cams on the camshaft.

Page 48


Notes

Page 49


Connecting Rod

The steel connecting rod is partially forged. The separation of connecting rod from bearing cap is made by 'cracking'. Compared with the conventional, costly separating process, 'cracking' brings high dimensional stability to the large connecting rod eye. Four laserstructured surfaces have additionally been applied. These improve the bearing shells' anti-twist protection. The separation point at the large connecting rod eye is set obliquely. Connecting rod and bearing cap are linked positively and frictionally with each other by two stretch-thread bolts. The ignition power is absorbed evenly at the small, trapezoidal connecting rod eye by a solid bronze bushing. Two oil holes have been made in the connecting rod eye for the oil supply to the small end bearing.

Page 50


Crankcase

Design features: Compact design, by integrating the oil cooler, coolant pump coil, unit pumps, and the coolant, fuel and oil ducts. Highly rigid alloy cast iron. Rigid crankcase deck and stable liner bottom collar support, with low-set threads on the cylinder head bolts. This results in lowwarp absorption of the thread connection and ignition forces by the rigid collar of the wet cylinder liner. Rigid side walls extending well below the center of the crankshaft, and bolted together with the crankshaft bearing caps.

With new vermicular graphite cast iron (GGV) material on OM 501 diesel engines with more than 300 kW (408 hp) and on OM 502 diesels with 405 kW (551 hp) and more.

Page 51


Cylinder Liners The cylinder liner has been fitted with an oil scraper ring to prevent carbon buildup. The oil scraper ring replaces the induction hardening in the upper part of the cylinder liner.

Piston Scraper ring

Crankcase

Sealing ring

Cylinder liner

old

Page 52


new

Cylinder Liners The cylinder liner (2) has been fitted with an oil scraper ring (3) to prevent carbon buildup. The chrome-molybdenum (CrMo) oil scraper ring (3) has a height of 13.5 mm and a projection of 0.15 mm to the inner diameter of the cylinder barrel in the cylinder liner (2). The oil scraper ring (3) replaces induction hardening in the upper part of the cylinder liner (2). The oil scraper ring's (3) projection reduces carbon deposits on the top land of the piston (area from the piston crown to the first piston ring groove). This reduces wear on the cylinder barrel of the cylinder liner (2).

2 Cylinder liner 3 Oil scraper ring 4 Sealing ring

The outside diameter on the liner collar has been enlarged to improve the fit of the cylinder liner (2) in the cylinder crankcase. The sealing ring (4) between the collar of the cylinder liner (2) and the cylinder crankcase is made of stainless steel (X5CrNi 18-10) and has a larger outside diameter than the tombac ring used previously. This results in higher abrasion resistance, reduced wear and improved installation reliability for the sealing ring (4). Due to the oil scraper ring (3) in the cylinder liner (2), an assembly tool is required to install the pistons.

Page 53


Notes

Page 54


Fuel System

Page 55


Fuel System The low-pressure fuel system has been specially designed to meet the requirements of the high-pressure injection system with individual unit pumps on V-engines. Unlike on conventional injection systems, to ensure stable injection, a high pre-pressure is necessary in the low-pressure system and a large flush volume for cooling the control valve solenoids in the unit pumps. 1 Fuel tank 1.1 Fuel strainer (800 m) 2 Fuel prefilter (KVF 300 m) with manual fuel feed pump 3.1 Plug-on valve in fuel feed (locked open) 3.2 Plug-on valve in fuel return (locked open) 4. Fuel heat exchanger 5. Fuel pump (KFP) 5.1 Pressure relief valve (9.0 - 12.0 bar) 6. Fuel filter (5 m) 6.1 Fuel filter drain valve 6.2 Constant vent in fuel filter (0.7 mm) 7. Nozzle holder combination 8. PLD unit pumps (Y6 to Y13) 9. Banjo union with constant vent (0.7 mm) 10. Overflow valve (2.0 bar up to engine No. 092 407, 2.65 bar from engine No. 092 408) 10.1 Throttle (3.1 mm) in overflow valve 11.1 Fuel feed connector (in frame) 11.2 Fuel return connector (in frame) 12 Throttle (0.5 mm) in flame starting system fuel line B10 Fuel temperature sensor R3 Flame glow plug Y5 Flame starting system solenoid valve

Page 56


Test points I

II

III IV

V

Fuel pressure after fuel filter Idle speed: 1.8 - 2.8 bar up to engine No. 092407, 2.2 – 3.2 bar from engine No. 092 408 Cutoff speed: 4.5 – 5.5 bar Fuel pressure after fuel pump Idle speed: 2.1 – 3.0 bar Cutoff speed: 5.0 – 6.0 bar (limit value 6,5 bar) Fuel intake pressure before fuel pump Cutoff speed: -0.35 to -0.25 bar Fuel return quantity at fuel tank Idle speed: 0.6 – 1.0 l/min Cutoff speed: 1.0 -1.6 l/min Low pressure-fuel system leaktightness Test pressure 5.5 bar/test period 5 minutes: no pressure drop Fuel return quantity at nozzle holder combination Idle speed: oil-damp Cutoff speed: drops only at most.

Fuel Filter Filter removal: 1.

2.

Unscrew the fuel filter screw cap. Only remove screw cap with filter insert about 1 cm. After the fuel has run out remove filter from the housing. Remove the filter insert from the cap by pressing at the side of the filter.

Filter installation: 1. 2. 3. 3. 4.

Replace the sealing ring Insert new filter element in screw cap Screw on the screw cap with filter element, and tighten. Torque value writen on cap Start the engine and bleed the fuel system. Check the filter for leaktightness with the engine running.

Page 57


Fuel prefilter with heated water separator In countries where the fuel is considered to be heavily contaminated and to have a high water content, an additional fuel filter with integrated water separator (including manual feed pump) is highly recommended. Engines that are operated in countries of Eastern Europe, or filled with fuel from those countries, must be fitted with a prefilter.

Advantages to the customer: • Increased durability of the injection system • Long maintenance intervals despite difficult operating conditions • Greater economy through shorter vehicle downtimes

Page 58


Fuel prefilter with heated water separator Filter removal: 1. Place a buket under the prefilter 2. Open the drain valve (10) and bleed screw (6) Let the filter element (2) run dry Dispose of the water/fuel mixture in env. acceptable manner. 3. Pull out the heater plug (9) 4. Unscrew filter element (2) 5. Unscrew the separator (3) from the filter element (2). If damaged, replace the separator 6. Clean the separator (3) Ensure that the sealing ring groove is clean! Filter installation: 1. Moisten the new sealing rings with engine oil. 2. Screw the separator (3) with new sealing ring (8) onto the filter element (2) and finger-tighten. 3. Screw the filter element (2) with new sealing ring onto filter head (1) and finger-tighten. Do not use tools to tighten! 4. Close drain valve (10). 5. Fill the prefilter with a manual fuel feed pump (5). 6. Close the bleed screw (6). 7. Start the engine and bleed the fuel system. Let the engine run for about 1 minute. The fuel system is bled automatically. 8. Check the prefilter for leaktightness.

Page 59


1

6

5 2

9 3

10

Checking The Fuel System In what circumstances must the fuel pressure be checked? Poor startup, poor performance What can cause the fuel pressure to be too low? Dirty prefilter, dirty fuel filter, faulty overflow valve, fuel system is drawing in air, kink in feed line from tank, intake line at fuel tank sensor, check valve in fuel feed, leak in filter bowl at the return flow, faulty feed pump What can cause the fuel pressure to be too high? Faulty overflow valve, kink in return flow line, check valve in the fuel return line, fuel tank sensor clogged What other operations should be carried out? Check the fuel system at and in the engine for leaktightness, check the fuel intake pressure, measure the fuel return quantity and check for air bubbles.

Page 60


Notes

Page 61


Oil Cooler And Oil Filter Housing The most important components of the engine lubrication / cooling system are: - Oil pan - Oil pump with pressure relief valve - Oil retention valve (return flow check valve) - Oil/water heat exchanger - Oil filter with drain valve and filling valve - Filter bypass valve - Main oil duct, oil ducts and oil lines - Oil spray nozzles - Oil temperature sensor and oil pressure sensor - Oil level sensor - Rocker arm spindle, rocker arm with oil hole

Page 62


Oil Cooler And Oil Filter Housing - Components 1

The following components are integrated in the aluminum die-cast housing of this assembly: 1 Oil filter 2 Oil temperatur sensor 3 Oil pressure sensor 4 Coolant temperatur sensor 5 Connection for oil filling

4 2

5

3

6 Filter bypass valve (opening pressure 2,3...3,0bar)

7 6

Page 63


7 Oil/water heat exchanger 8 Filter drain valve

8

Components Of The Lubricating System Oil pump The oil pump is in the form of a gear type oil pump. The gear type oil pump is located at the rear of the crankcase. The oil pump is driven by the crankshaft. It delivers the engine oil from the oil pan through an oil duct to the oil retention valve, then to the lateral main oil duct and the oil/water heat exchanger. Pressure relief valve The pressure relief valve is located under the oil pump and maintains constant oil pressure. If too much oil is delivered at high engine speeds, the pressure relief valve opens and allows the engine oil to flow directly from the oil pump back to the oil pan. Oil retention valve (return flow check valve) The return flow check valve is placed at the right rear in the crankcase and is intended to prevent engine oil flowing back into the oil pan when the engine is stopped. The oil ducts are therefore always filled with oil. When the engine is restarted, this ensures that components always receive optimal lubrication from the beginning. Oil/water heat exchanger The oil/water heat exchanger is located in a housing assembly on the front of the crankcase, with integral oil/water heat exchanger and oil filter. The engine oil flows through the plates in the oil/water heat exchanger, and these are washed around by the engine coolant. Since the engine coolant is at a considerably lower temperature than the engine oil, the coolant absorbs the heat from the engine oil and cools it down to engine operating temperature. During cold starts, the engine oil is warmed up by the surrounding coolant through of the oil/water heat exchanger. Oil ducts and oil lines Oil ducts are integrated into the crankcase and cylinder heads. The oil pressure and oil return lines to the turbocharger are located externally. The oil retention valve is located at the start of the lateral main oil duct, which is placed on the right of the crankcase. From two further oil ducts located centrally at camshaft level in the crankcase, other oil ducts (Y and cross-drillings) go to the individual oil spray nozzles, camshaft bearing, crankshaft main bearing, MR/PLD unit pumps and the individual cylinder heads. Engine oil is fed from the main oil duct, through an oil duct system in the rear wall of the crankcase, to the turbocharger oil pressure line and both compressor bearings. The oil ducts in the crankcase are partly closed with screw plugs or balls.

Page 64


Components Of The Lubricating System The connecting rod bearing is supplied with engine oil through oil ducts integrated into the crankshaft. Engine oil is delivered to the bearing brackets of the individual rocker arm spindles through holes in the cylinder head gasket and the oil duct in the cylinder head. From the rocker arm spindle bearing bracket, oil is supplied to the rocker arm spindle and all the rocker arms. It then passes through the oil holes in the rocker arms and also supplies the valve assembly. The oil then flows back to the oil pan through oil return holes in the cylinder head and crankcase. Oil filter The oil filter housing is fitted to the left front of the crankcase. It contains an oil filter insert, made of paper. The oil filter insert is clipped into the oil filter cover and is replaced from the top. When the filter cover is unscrewed, engine oil in the filter housing flows through the drain valve back into the oil pan. Drain valve The drain valve is located in the oil filter housing under the filter insert, and opens when the filter cover is unscrewed. This ensures a cleaner filter change and less environmental pollution by reducing the amount of residual oil in the old filter.

Filter bypass valve The filter bypass valve (release pressure 2. 3 - 3. 0 bar) is located in the housing assembly under the oil/water heat exchanger and connected with the oil filter through an oil duct. The normal position of the filter bypass valve is closed. If the oil filter insert is clogged, the pressure increase in the filter housing opens the filter bypass valve. This ensures that the engine is lubricated, although the engine oil passing through the bypass valve is unfiltered. Filling valve The filling valve is placed at the bottom of oil filter housing and is closed with a screw plug (M33x2). Through this valve, engine oil can be poured into the engine assembly, and after repairs to the engine oil system before starting the engine.

Page 65


Components Of The Lubricating System Oil spray nozzles The oil spray nozzles are located in the crankcase, one per cylinder. Oil is supplied to the oil spray nozzles through both oil ducts. The nozzles spray engine oil continuously under the piston crowns, thus cooling them, while at the same time the piston crowns are lubricated by engine oil dripping through an opening in the top of the connecting rod. The oil spray nozzles also spray engine oil through another hole onto the valve and unit pump cams on the camshaft. Oil temperature sensor and oil pressure sensor The oil temperature and oil pressure sensor is screwed from the front into the housing assembly under the oil/water heat exchanger, and connected with the oil filter through an oil return duct.

Page 66


Eingine Oil And Filter Change Only change the engine oil with the engine warm! 1. 2. 3. 4.

Unscrew oil filter cap approx. 1cm, filter housing will then train empty. When housing is empty, remove filter from from cap by pressing at the side of the filter Replace o-ring and insert new filter in cap. Tighten cap with specified torque (writen on cap) Drain off the engine oil at the oil drain plug on the oil pan. Fit new sealing ring to the oil drain plug. Screw in the oil drain plug and tighten. Drain plug on oil pan

Light alloy Plastic

5. 6. 7. 8. 9.

M20x1,5 M26x1,5 without steel insert with steel insert

60 Nm 80 Nm 40 Nm 60 Nm

Pour in the specified quantity and quality of engine oil at the oil filler plug. Mercedes Benz BeVo http://bevo.mercedes-benz.com Start engine Watch the engine oil pressure gauge! It should indicate pressure after several seconds. Do not rev the engine until oil pressure is indicated. Allow the engine to run for 1 - 2 min at idle speed, once the oil pressure is indicated. Wait for about 5 minutes, then check the oil level and adjust if necessary. The waiting time must be observed. Check the oil filter, the oil pan drain plug if necessary, and the long-life oil filter for leaktightness.

Page 67


Notes

Page 68


Crankcase Ventilation System Cyclone separator functional principle

3

The blow-by gases from the crankcase are sent as pre-cleaned crude gases to the cyclone separator insert (1). The cyclone separator insert (1) is made up of two cyclones. The crude gas enters the cyclone from the side (tangentially). The gas stream is forced into a downwards spiral movement in the entry chamber. This causes the floating oil particles to be pitched towards the wall of the cyclone by the centrifugal forces and then slide down the tapered surfaces of the swirl chamber due to gravity and the downwards movement of the gas. The oil comes out through a hole (2) at the lowest point of the cyclone. As the cyclone tapers towards the bottom, the circumferential speed and centrifugal effect becomes greater so that finer particles can be separated in the lower section. At the lowest point of the cyclone the whirling gas reverses direction and goes back up and the clean gas is guided out through an outlet pipe (3) (take-off tube) at the top. The diameter and tapered form of the take-off tube determine the pressure loss and separation quality of the cyclone. A vacuum diaphragm (5) controls the pressure in the engine oil gallery. The bypass valve (4) opens up with a high gas flow.

Page 69


1 4 5 2

Crankcase Ventilation System

Clean gas outlet

Crude gas entry

Oil return Page 70


Notes

Page 71


Coolant Distribution Internal water guide Coolant is delivered from the water pump coil integrated into the front of the crankcase, and flows through the plate-type oil cooler in the oil filter housing, which projects into the central water channel. From the central water channel in the crankcase, each cylinder is supplied with water uniformly through individual, tangential water channels. The water flow around the cylinder liners is divided in two by a fin. This ensures the coolant flow in the lower cylinder area and an even main flow in the upper area, for intensive cooling of the piston TDC areas where the thermal load is high. Coolant flows through the drillings in the crankcase into the cylinder head. Particularly intensive cooling of the valve lands and nozzle area is achieved by special forming of the water jacket in the cylinder head. Coolant flows back through openings in the crankcase into two return channels cast into the crankcase, one per cylinder bank. The return channels are connected to a cross-duct integrated in the oil filter/oil cooler housing assembly, through which coolant flows back into the double thermostat housing joined to the coolant pump.

Page 72


Thermostat Location

The installation location of the thermostats is shown on the right illustration. The circles point to the bleed tabs. These tabs must point upwards. The standard thermostat starts to open at 83°C.

Coolant must be changed in regular intervals. See also maintenance booklet and BeVo

Page 73


Air And Exhaust Ducting from air filter

to charge air cooler Air Exhaust

from charge air cooler

Page 74


Air And Exhaust Ducting

On some engines, exhaust pipes with imprinted arrows are used. The arrow imprint must point towards the turbocharger support! Parts must be assembled free of tension and a tightening torque of 50 Nm must be applied.

Page 75


Notes

Page 76


Cylinder Liner Assessment Matt gray surface, honing pattern visible, dry cylinder barrel, without oil residues, without shining areas or reflecting areas of smoothness. There should not be any burn marks or streaks on the cylinder barrels or liners. Individual, slight drawing scores are non-critical. The honing pattern is more or less clearly recognizable over the cylinder barrel. At the reversal point of the piston ring, the honing pattern may be partially eroded.

The cylinder liner or the crankcase can be reused.

Page 77


Cylinder Liner Assessment

With engines 904.9, 906.9 only The stripe profile (arrows) in the upper area of the cylinder barrel arises due to induction hardening on production of the crankcase, and is to be regarded as the normal condition. The longer the engine's operating time, the less visible the stripe pattern becomes.

Page 78



The following applies if carbon is present in the top land area: Clean the top land area and reuse the cylinder liner. Additionally remove the piston and assess the piston rings.

Page 79


The following applies if individual, continuous scratches or score marks are present: The cylinder liner can be reused if slight scratches or score marks are present.


The following applies if ring shaped depressions are present at the upper and lower piston ring reversal point with visible color shadings (arrow), but the honing pattern can still be recognized:

The following applies in the case of pressure sheen marks and smoothness, e.g. individual, bare areas (arrow) in the cylinder barrel or allround indentations at the upper and lower piston ring reversal point:

The cylinder liner or the crankcase can be reused.

The cylinder liner must be replaced.

Page 80



The following applies in the case of imperceptible dry friction marks or deposits (arrow) on the cylinder barrel running downwards from the 2nd or 3rd piston ring:

The following applies if the honing pattern is only barely or not visible or there is a perceptible wear step at the upper reversal point of the first piston ring (arrow):

The cylinder liner is unusable and must be replaced. The piston should also be replaced.

The cylinder liner is unusable and must be replaced.

Page 81


Cylinder Liner Assessment Only series 900 If the model series 900 engine reveals no inengine complaints, e.g. noises or increased engine oil consumption, the crankcase can be reused.

Page 82


Notes

Page 83


Series 460

Baureihe 457 Series 460

6-Cylinder in line engine 6-Zylinder Reihenmotor

OM OM 457 460LA LA VH = 12l

Page 84


OM 460 LA

Page 85


Technical Features Series 460                        

High-strength, noise-optimised cylinder housing of high-additive cast iron. Compact design and high functional reliability through integration of the oil cooler, the unit pumps, and the coolant, fuel and oil ports into the crankcase. Engines in three different power categories, which already correspond to the EURO III or Euromot/EPA Level 2 standard from the start of production. Highly rigid oil pan of light alloy. Seven-journal crankshaft with counterweights bolted on. Induction-hardened bearing points and fillet radius. Fitted bearing located at the central bearing support for technical reasons related to vibrations. Crankshaft seal of radial sealing rings with nonwoven dust lip. Camshaft drive through flywheel side gear drive. Fuel delivery pump driven by a camshaft on the belt side. Oil pump in the oil pan, driven by gears on the flywheel side. Maintenance free poly-V-belt drive for all assemblies. Planetary gear drive starter on right at the flywheel. MR control unit with additional fuel cooler. Intake valve seat rings of Tribaloy, a high-carbon tungsten/steel alloy. These have to be smoothed when installed. Piston cooling though oil spray nozzles. Camshaft/unit pump lubrication through additional oil spray nozzles. Four-valve technology with 2 intake and 2 exhaust valves per cylinder. MR engine control with the engine electronics located directly on the engine. Pump-line-nozzle system with solenoid-controlled unit pumps. Electronically controlled high-pressure direct injection at 1800 bar. Direct injection with centrally positioned injection nozzle. Turbocharger with charge air cooling. Engine power take-off at rear, also possible at front by means of additional belt drive for ancillary assemblies (special equipment). Can operate with biodiesel (RME).

Page 86



Page 87



Page 88



KGS

Page 89


1

2

3

4

5

6

KS

Information

The following components are in funktion and handling similar to the series 500, therefore they are not dicribed in detail under the section „Series 460“ Dimensions and part numbers can deviate from the series 500. Cylinder head Page 30 and 91

Fuel pre filter & Fuel pre filter change Page 58

Unit pump Page 43

Engine oil and filter change Page 67

Nozzle holder kombination Page 39

Crankcase Ventilation System Page 69

Piston Page 46

Cylinder liner assessment Page 77

Cylinder liner Page 52 Fuel filter & Fuel filter change Page 57

Page 90


Cylinder Head

Main difference to serie 500 1 Coolant vent bore 2 Bolt pattern and bolts (Series 500 M18x2 / Series 460 M15x2)

1

2

Page 91


Cylinder Head Mounting The cylinder head is tightened in 6 stages. The cylinder head bolts do not require retightening. Moisten the bolts with engine oil! 1. 2. 3. 4. 5. 6.


10 Nm 50 Nm 100 Nm 200 Nm 90 ° 90 °

1

3

4

2


L

Page 92


Notes

Page 93


Valve Drive Gas exchange is improved by 4-valve technology, thus contributing considerably to lower fuel consumption with lower emissions. The intake and exhaust valves are controlled by means of roller tappets, push rods and intake and exhaust rocker arms which are set in a groove in the crankcase with a sliding block, and which operate the intake/exhaust valve pairs through a valve bridge. The rocker arm spindle complete with preassembled rocker arms and rocker arm bearing bracket is bolted to the cylinder head. To keep wear in the whole valve assembly to a minimum throughout ist lifetime, the contact surfaces of the valve, valve bridge, the rocker arm thumb, the upset ball socket of the push rod, and the ball head of the adjusting screw, are induction hardened. This is to allow them to support the actuation forces of the hightemperature valve springs, and the effects of inertial forces and cylinder pressures.

Page 94




I/E

Page 95


I

E

I

E

E

I

E

I

I/E

Notes

Page 96


Piston Cooling Unlike the familiar BR 500, the 460 model series has two oil spray nozzles per cylinder. One of these (on the right in direction of travel) performs the traditional task of piston cooling, while the other is placed separately (on the left in the direction of travel) and has the task of lubricating the camshaft.

Note: It is not permitted to adjust the oil spray nozzle. The oil splasher pipe is soldered in, and the adjustment process could cause initial damage.

Page 97


Connecting Rod

The steel connecting rod is partially forged. The The separation point at the large connecting rod eye is set obliquely. Connecting rod and bearing cap are linked positively and frictionally with each other by two stretch-thread bolts. The ignition power is absorbed evenly at the small, trapezoidal connecting rod eye by a solid bronze bushing. Two oil holes have been made in the connecting rod eye for the oil supply to the small end bearing.

Page 98


Crankcase The crankcase is made of high-additive cast iron. This gives it a high level of strength and stability, while producing lower noise emissions. The side walls of the crankcase extend well below the center of the crankshaft. This gives it even greater rigidity. Integration of the oil cooler, the unit pumps, and the coolant and fuel ports into the crankcase, gives the engine a very compact design. Exchangeable wet cylinder liners are used. On the left on the flywheel side, an assembling lug is provided for attaching the compressor coupled with the power steering pump.

Page 99


Notes

Page 100


Fuel System

Page 101


Fuel System 1 Fuel tank 1.1 Fuel strainer (800 m) 1.2 Air admission valve 2 Manual fuel feed pump 2.1 "RACOR" fuel prefilter (special equipment 3.1 Plug-on valve in fuel feed (locked open) 3.2 Plug-on valve in fuel return (locked open) 4 Fuel heat exchanger 5 Fuel pump 5.1 Pressure relief valve (7.0 - 8.0 bar) 6 Fuel filter (KF 3 m) 6.1 Fuel filter drain valve 6.2 Constant balance hole 7 Nozzle holder combination 8 PLD unit pumps (Y6 to Y11) 10 Overflow valve 10.1 Throttle in overflow valve (banjo bolt) 12 Throttle in flame starting system fuel line

Page 102


R3 Flame glow plug Y5 Flame starting system solenoid valve

A Fuel feed /intake vacuum side B Fuel feed / pressure side C Fuel high pressure side (injection line) after PLD unit pumps D Fuel return after unit pump / leak fuel E Fuel flush quantity (fuel short circuit)


Page 103


Notes

Page 104


Oil Cooler And Filter Housing The most important components of the engine lubrication / cooling system are: - Oil pan - Oil pump with pressure relief valve - Oil retention valve (return flow check valve) - Oil/water heat exchanger - Oil filter with drain valve and filling valve - Filter bypass valve - Main oil duct, oil ducts and oil lines - Oil spray nozzles - Oil temperature sensor and oil pressure sensor - Oil level sensor - Rocker arm spindle, rocker arm with oil hole

Page 105


Oil Cooler And Oil Filter Housing - Components The following components are integrated in the aluminum die-cast housing of this assembly: 1 Oil filter 2 Oil temperatur and pressure sensor 3 Connection for oil filling 4 Filter bypass valve 5 Oil/water heat exchanger 6 Filter drain valve 7 Oil retention valve

1 7

3

2

4

5

Page 106


7

6

Components Of The Lubricating System Oil pump The oil pump is in the form of a gear type oil pump. The gear type oil pump is located at the rear of the crankcase. The oil pump is driven by the crankshaft. It delivers the engine oil from the oil pan through an oil duct to the oil retention valve, then to the oil/water heat exchanger. Pressure relief valve The pressure relief valve is located under the oil pump and maintains constant oil pressure. If too much oil is delivered at high engine speeds, the pressure relief valve opens and allows the engine oil to flow directly from the oil pump back to the oil pan. Oil retention valve (return flow check valve) The return flow check valve is placed in the oil cooler and filter housing and is intended to prevent engine oil flowing back into the oil pan when the engine is stopped. The oil ducts are therefore always filled with oil. When the engine is restarted, this ensures that components always receive optimal lubrication from the beginning. Oil/water heat exchanger The oil/water heat exchanger is located in a housing assembly on the left side of the crankcase, with integral oil/water heat exchanger and oil filter. The engine oil flows through the plates in the oil/water heat exchanger, and these are washed around by the engine coolant. Since the engine coolant is at a considerably lower temperature than the engine oil, the coolant absorbs the heat from the engine oil and cools it down to engine operating temperature. During cold starts, the engine oil is warmed up by the surrounding coolant through of the oil/water heat exchanger. Oil ducts and oil lines Oil ducts are integrated into the crankcase and cylinder heads. The oil pressure and oil return lines to the turbocharger are located externally. The oil retention valve is located in the oil cooler and filter housing, which is placed on the left side of the crankcase. From the oil duct located on the left side of the crankcase, the oil ducts goes to the individual oil spray nozzles, camshaft bearing, crankshaft main bearing, MR/PLD unit pumps and the individual cylinder heads. Engine oil is fed to the turbocharger oil pressure line and both compressor bearings. The oil ducts in the crankcase are partly closed with screw plugs or balls.

Page 107


Components Of The Lubricating System The connecting rod bearing is supplied with engine oil through oil ducts integrated into the crankshaft. Engine oil is delivered to the bearing brackets of the individual rocker arm spindles through holes in the cylinder head gasket and the oil duct in the cylinder head. From the rocker arm spindle bearing bracket, oil is supplied to the rocker arm spindle and all the rocker arms. It then passes through the oil holes in the rocker arms and also supplies the valve assembly. The oil then flows back to the oil pan through oil return holes in the cylinder head and crankcase. Oil filter The oil filter housing is fitted to the left side of the crankcase. It contains an oil filter insert, made of paper. The oil filter insert is clipped into the oil filter cover and is replaced from the top. When the filter cover is unscrewed, engine oil in the filter housing flows through the drain valve back into the oil pan. Drain valve The drain valve is located in the oil filter housing under the filter insert, and opens when the filter cover is unscrewed. This ensures a cleaner filter change and less environmental pollution by reducing the amount of residual oil in the old filter.

Filter bypass valve The filter bypass valve (release pressure 2. 3 - 3. 0 bar) is located in the filter dome. The normal position of the filter bypass valve is closed. If the oil filter insert is clogged, the pressure increase in the filter housing opens the filter bypass valve. This ensures that the engine is lubricated, although the engine oil passing through the bypass valve is unfiltered. Filling valve The filling valve is placed at the bottom of oil filter housing and is closed with a screw plug (M33x2). Through this valve, engine oil can be poured into the engine assembly, and after repairs to the engine oil system before starting the engine.

Page 108


Components Of The Lubricating System Oil spray nozzles The oil spray nozzles are located in the crankcase, two per cylinder. Oil is supplied to the oil spray nozzles through the oil duct. The nozzles spray engine oil continuously under the piston crowns and the camshaft, thus cooling and lubricating them, while at the same time the upper connecting rod bearings are lubricated by engine oil dripping through an opening in the top of the connecting rod. Oil temperature sensor and oil pressure sensor The oil temperature and oil pressure sensor is screwed from the front into the housing assembly under the oil/water heat exchanger, and connected with the oil filter through an oil return duct.

Page 109


Notes

Page 110


Thermostat Location

The installation location of the thermostats is shown on the right illustration. The circles point to the bleed tabs. The standard thermostat starts to open at 83°C.


Page 111



from charge air cooler to charge air cooler

Exhaust Air

Page 112


Notes

Page 113


Series 900 Engine Models

Baureihe 900 Series 900

4-cylinder in line engine 4-Zylinder Reihenmotor

6-Zylinder 6-cylinder in Reihenmotor line engine

OM 904 924 LA 904 /LA

OM 906 926 LA 906 /LA

VH = 4.25 / 4.8 l

VH = 6.37 / 7.2 l

Page 114


OM 906 LA

Page 115


Technical Features Series 900  Outstanding power output and torque characteristics over the whole rpm range  Dynamic start-off characteristics and pulling power  Attractive power/weight ratio  Low fuel consumption  High-pressure direct injection with unit pump, pump-line-nozzle system, with peak pressures up to 1 800 bar.  Electronic engine control (MR) with electronic system fixed to the engine, and extensive engine protection functions  Direct injection with centrally positioned injection nozzle.  3-valve technology with 2 intake valves and one exhaust valve  Pneumatically or hydraulically controlled constant throttle  Useful engine brake rpm well over rated rpm, up to 2700 rpm  Meets the emission legislation of Euromot IIIa  Turbocharger with charge air cooling  Turbocharger with wastegate valve, depending on engine model  Rated engine speed 2200 rpm or 2300 rpm  Low service requirements • long maintenance intervals • engine oil and fuel filter located at front for easy maintenance • maintenance-free belt drive  Can run on FAME / RME (rape methyl ester) or biodiesel, and engine oil changes are halved  High reliability and long runtime  Low number of parts variants - many parts are the same on both 4 and 6 cylinder engines  Rear engine power take-off ex works

Page 116



Page 117



Page 118



KGS

Page 119


1

2

3

4

5

6

KS

Cylinder Head Shown on engine 926.9 At the rear part of the cylinder head the cap (arrow) has been replaced by the coolant flange for the SCR tank heater solenoid valve. On the side of the cylinder head the caps have been partly replaced by threaded sleeves (1). The bracket for the AdBlue metering device is mounted on these threaded sleeves (1). The other holes on the sides of the cylinder head are sealed by screw plugs (2). The cylinder heads in the 924.9 and 926.9 engines have been converted to vermicular graphite cast iron (GGV-40), for greater strength in order to withstand the higher ignition pressure.

1 Threaded sleeve 2 Screw plugs

Page 120


Cylinder Head – Sealing Surface Assessment Check flatness of the cylinder head sealing surface via visual inspection. In the area of the lines, place a straightedge over the coolant bores (W) on the cylinder head sealing surface. Check flatness within the sealing area (X) of the cylinder head gasket only. If a gap forms under the straightedge on the cylinder head sealing surface, the cylinder head sealing surface must be face-ground or the cylinder head exchanged. When face-grinding, the following notes have to be observed: - Only carry out face-grinding if an impermissible deviation in flatness is measured in the longitudinal direction. - Material removal on the cylinder head must not fall below the permissible overall cylinder head height, "minimum height". - Only face-grind the cylinder head sealing surface via face grinding. - The surface quality of the cylinder head sealing surface must be maintained.

Page 121


Cylinder Head Gasket

1

1

4

1

4

4

1

1

1 4

4

4

4

1

2 4

4

1 3

5

3

4

1 3

3

1 Coolant 2 Pressure oil 3 Push rods / oil return 4 Head bolts 5 Return oil crankcase ventilation

Page 122


4

1 3

4 1

3

3

4

1 3

3

3

4

1 3

3

Cylinder Head Mounting The cylinder head is tightened in 6 stages. The cylinder head bolts do not require retightening. Moisten the bolts with engine oil!

1. 2. 3. 4. 5. 6.


20 Nm 70 Nm 170 Nm 280 Nm 90 ° 90 °


L

Page 123


Notes

Page 124


Valve Drive The 900 model series has two intake valves and one exhaust valve per cylinder. It is therefore referred to as a "3-valve" engine. The steel camshaft (which has 5 bearings on the 4-cylinder and 7 bearings on the 6-cylinder engine) has one intake and one exhaust cam per cylinder, plus one cam for driving the unit pump. All valves are driven by the camshaft, by means of mushroom tappets and short push rods. A floating valve bridge links and actuates both intake valves. The complete valve actuation system with rocker arm bearing brackets is bolted to the cylinder head as a preassembled unit.

Page 125



Page 126



Inlet

Exhaust

Notes

Page 127


Pump-Line-Nozzle Injection System (PLD) Location of the unit pump The injection process is performed by the newly developed pump-linenozzle system, controlled by the Telligentelectronic engine management system. In the MR system, fuel is delivered to the injection nozzle by individual unit pumps over short, relatively rigid high-pressure injection lines, and through the pressure pipe connection screwed into the cylinder head. A unit pump fitted to the crankcase is assigned to each cylinder. The pump is driven by another timing cam on the camshaft. The camshaft therefore also has the task of driving the unit pumps, besides the traditional function of driving the intake and exhaust valves. The operating principle of the unit pump is based on the same principle as the piston pump, as in the in-line injection pumps used till now, but without control edges at the pump plunger. The quantity injected is determined individually per cylinder by solenoid valves, which control the start and end of injection.

Page 128


Pressure Pipe Connection And Nozzle Holder Location The pressure pipe with integral pin-type filter forms the connection from the high-pressure injection line to the vertical, centrally positioned nozzle holder combination with the injection nozzle. The nozzle holder combination is placed inside a protective sleeve and is attached to the cylinder head by means of a clamping claw. The combustion gas seal consists of a sealing sleeve.

1 6

3 4

5

The protective sleeve itself is protected from the coolant by an O-ring, and on the pressure side by the thread and the contact surface. 1 2 3 4 5 6 7 8 9

Page 129


Injection line, 25 Nm Pressure screw, 40 Nm O-Ring Pressure pipe Nozzle holder kombination O-Ring Screw, 35 Nm Clamping claw Constant throttle cap

2

5 8

9 7

Removing The Nozzle Holder Combination

Injector removal

1 6

1. Remove fuel line (1). 3. Remove thrust screw (2). 4. Pull off pressure pipe neck (4). 5. Remove screw (7). 6. Take off clamp (8). 7. Screw impact extractor (10) into injector. 8. Remove injector using the impact extractor. 9. If necessary remove sealing sleeve with extractor (11) from cylinder head. 10. Seal all openings with appropriate covers after removal. 11

Page 130


10

3 4

5

2

5 8

1 2 3 4 5 6 7 8 9


9 7

Install The Nozzle Holder Combination

1 1. 2. 3. 4. 6. 7.

8.

Insert a new O-ring (3) at nozzle holder combination (5) Press new sealing sleeve (11) with special tool (12) onto nozzle holder combination (5) Install nozzle holder combination Mount the clamping claw (8), and tighten Screw (7) to 35Nm Place the new O-ring (6) at pressure pipe connection (4) Fit the pressure pipe connection (4) and tighten pressure screw (2),40 Nm. Moisten the pressure pipe connection around the taper seal with engine oil. Install the injection line (1) 12 11

Page 131


1 2 3 4 5 6 7 8 9


6

3 4

5

2

5 8

9 7

Injection Pump Removal

Injection pump removal 1. Disconnect wiring (7) from injection pump. 2. Remove fuel line (6). 3. Unscrew securing screws (5) of injection pump by approx. 10 mm. The preloaded compression spring presses the injection pump out of the crankcase. If not use special tool (10) and carefully extract pump. 4. Remove injection pump securing screws (5). 5. Remove injection pump (1). 6. Remove sealing rings (2, 3, 4) from injection pump. 7. Seal all openings with appropriate covers after removal.

10

Page 132


Injection Pump Installation Injection pump installation 1. Remove all covers from openings Coat the new o-rings (2, 3, 4) with lubricating grease, and install them with special tool (8). Note: The black o-ring must be allways on top! 3. Carefully clear any dirt or paint residues away from the sealing surface of the MR/PLD unit pump and the crankcase. 4. Carefully press the unit pump in by hand. If the unit pump cam is up at the camshaft, turn the engine. 5. Install the bolts (5) and tighten to 60Nm. 6. Install injection line (6) and tighten to 25Nm. 7. Connect wiring (7) (1,5 Nm). 8. If pump has been changed, new pump code must be programed via the MiniDiag2.

8

Page 133


Notes

Page 134


Piston Pistons and piston rings are among the most highly stressed engine components. Pistons are therefore constructed of high-temperature aluminum alloy. The piston top land and stem are graphite-coated to increase runningin and limp-home capability. There is a cast-in, reinforced ring groove for the first piston ring. The piston pin support is trapezoidal in shape, to increase the pressure-load surfaces on the piston and connecting rod.

Features of the piston rings: Groove 1: Compression ring Cast-iron keystone ring with plasma spray layer of chromeceramic, spherical-lapped. Groove 2: Compression ring with oil-scraper action. Chrome-plated taper-faced ring with internal angle underneath. Groove 3: Oil scraper ring Roof bevel ring with chrome-plated, lapped lands and garter springs.

Page 135


Piston Cooling

The oil spray nozzles are located in the crankcase. There is one oil spray nozzle per cylinder. The oil spray nozzles spray engine oil continuously under the piston crowns to cool them down. Oil is supplied to the oil spray nozzles through the main oil duct.

Note: It is not permitted to adjust the oil spray nozzle. The oil splasher pipe is soldered in, and the adjustment process could cause initial damage.

Page 136


Connecting Rod A particular feature of the manufacturing technology used to produce the forged steel connecting rod is the 'cracking' process used to separate the rod from the bearing cap. With this process, the connecting rod (produced in one piece up to now) is split at the big connecting rod eye at an exactly pre-determined fracture line. The separated parts are then bolted together to form a precise, exact-fitting attachment for the bearing. Note: Because of the 'cracked' surface structure, special care and cleanliness is required when performing repairs.

Page 137


Crankcase All engines are based on the particularly stable, noise-optimized crankcase, which is made of a high-carbon/ cast iron alloy. Design features: Both the 4 and the 6-cylinder engine have only one variant. Compact design through integration of the oil cooler, the unit pumps, and the coolant, fuel and oil ports. Highly rigid, high carbon /cast iron alloy. Rigid sidewalls, extending well past the center of thecrankshaft. This means that the separating surface of the oil pan is located lower than the level of the crankshaft center. The front engine mount is located at cylinder 2. Induction-hardened cylinder contact surfaces. On the left on the flywheel side, an assembling lug is provided for attaching the compressor with power steering pump.

Page 138


Induction-Hardened Cylinder Contact Surfaces

Cylinder contact surfaces with induction-hardened strips are provided at the upper piston return point, around the rings, to increase engine life.

Page 139


Notes

Page 140


Fuel System

Page 141


Fuel System Fuel circuit schematic diagram 1 Fuel feed pump (KFP) 1.1 Pressure limiting valve in KFP pump (9.2 bar) 1.2 Check valve in KFP pump (0.2 bar) 2 Fuel filter (KF) 2.1 Fuel drain valve 2.2 Constant vent in fuel filter (KF) 3.1 Bypass from fuel feed duct to fuel return duct 5 Nozzle holder combination 8 Overflow valve (4.5 bar) 8.1 Constant vent (0.5 mm) 10 PLD unit pumps (Y6 to Y11) 12 Fuel prefilter (KVF) 12.1Check valve in prefilter (KVF) 14.1 Plug-on valve in fuel feed (locked open) 15.1Plug-on valve in fuel return (locked open) 17 Fuel tank 17.1Air intake valve 18.1Throttle (0.5 mm) in flame start fuel line 18.2 Throttle (threaded orifice) in flame start fuel line B10 Fuel temperature sensor R3 Flame start glow plugs Y5 Solenoid valve

Test points, inspection data G Pressure gauge testing H Fuel return quantity testing

Fuel system A Fuel feed (intake/vacuum side) B Fuel return (leak fuel) C Fuel feed (pressure side) D Fuel high pressure side (after PLD unit pumps) E Fuel return (fuel drain)

Page 142


I

Fuel pressure after fuel filter Idle speed: 4.3 bar Cutoff speed: 4.0 - 6.5 bar

II

Fuel return quantity at nozzle holder combination Test period: 5 min no fuel

III

Fuel return quantity at fuel filter bowl outlet Idle and cutoff speed: 0.3 l/min Fuel return quantity at overflow valve Idle speed: 0.9 -1.7 l/min Cutoff speed: 2.7 - 7.5 l/min

IV

Fuel intake pressure before fuel pump Idle speed: -0.09 to -0.12 bar Cutoff speed: -0.4 to -0.5 bar

V

Low pressure-fuel system leaktightness Test pressure: 5.0 bar Test period: 5 min Pressure drop: 0.25 bar

Fuel Filter The fuel filter housing from the series 900 consists of: 1. 2.

Fuel pre-filter with non return valve Fuel filter

2 2

1

Page 143


1

Fuel Filter Filter removal: 1. 2. 3.

4.

4

3

Unscrew cap (3) from pre-filter. Remove pre filter (1) from housing and clean. Unscrew cap (4) from filter housing. Only remove screw cap with filter insert about 1 cm. After the fuel has run out remove filter from the housing. Remove the filter insert from the cap by pressing at the side of the filter.

Filter installation: 1. 2. 3. 4. 5. 6.

Replace the sealing rings Insert new filter element (2) in screw cap (4). Screw on the screw cap with filter element, and tighten. Torque value writen on cap. Insert cleaned pre-filter (1) in housing and tighten cap (3) Torque value writen on cap. Start the engine and bleed the fuel system. Check the filters for leaktightness with the engine running.

4 2

3

Page 144


1


Page 145


Notes

Page 146


Oil Cooler And Filter Housing The most important components of the engine lubrication / cooling system are: - Oil pan - Oil pump with pressure relief valve - Oil retention valve (return flow check valve) - Oil/water heat exchanger - Oil filter with drain valve and filling valve - Filter bypass valve - Main oil duct, oil ducts and oil lines - Oil spray nozzles - Oil temperature sensor and oil pressure sensor - Oil level sensor - Rocker arm spindle, rocker arm with oil hole

Page 147


Oil Cooler And Oil Filter Housing - Components 1 Oil filter 2 Oil teperatur sensor 3 Filter bypass valve

5 1

(opening pressure 1, 8...2, 6 bar)

4 Oil/water heat exchanger 5 Oil retention valve 6 Filter drain valve

3 4 5

6

Page 148


2

Components Of The Lubricating System Oil pump The oil pump consists of a gear type pump and is located in the front end cover. It is driven by the crankshaft. It delivers the engine oil from the oil pan through an oil duct to the oil/water heat exchanger. Pressure relief valve The pressure relief valve is located under the oil pump and maintains the oil pressure at 3 to 4 bar. If too much oil is delivered at high engine speeds, the pressure relief valve opens and allows the engine oil to flow directly from the oil pump back to the oil pan. Oil/water heat exchanger The oil/water heat exchanger is located on the right side of the crankcase. The engine oil flows through the plates (8 elements) in the oil/water heat exchanger, and these are washed around by the engine coolant. Since the engine coolant is at a considerably lower temperature than the engine oil, the coolant absorbs the heat from the engine oil and cools it down to engine operating temperature. During cold starts, the engine oil is heated by the surrounding coolant through the oil/water heat exchanger. Oil ducts and oil lines Oil ducts are integrated into the crankcase and cylinder head. The oil pressure lines to the turbocharger and power take-off (special equipment, fitted to the crankcase) are located externally. The other oil ducts to the crankshaft bearings and oil spray nozzles are supplied with engine oil through the main oil duct, located on the right side of the crankcase. Other oil ducts lead in the crankcase from the individual crankshaft bearings and to the camshaft bearings. The connecting rod bearing is supplied with engine oil through oil ducts integrated into the crankshaft. Engine oil is fed from the main oil duct to the compressor and cylinder head through an oil duct system in the rear wall of the crankcase. A further longitudinal oil duct on the left side of the crankcase supplies engine oil to the MR/PLD unit pumps. Engine oil is delivered to the last rocker arm bearing bracket through holes in the cylinder head gasket and the oil duct in the rear of the cylinder head. From the rocker arm spindle bearing bracket, oil then passes to the rocker arm spindle and all the rocker arms. It then passes through the oil holes in the rocker arms and also supplies the valve assembly. The oil ducts in the crankcase are partly closed with screw plugs or balls. The oil then flows back to the oil pan through oil return holes in the cylinder head and crankcase.

Page 149


Components Of The Lubricating System Oil filter The oil filter housing is fitted to the right front of the crankcase. It contains an oil filter insert, made of paper. The oil filter insert is clipped into the oil filter cover. The oil filter insert is replaced from the top. When the filter cover is unscrewed, engine oil in the filter housing flows through the drain valve back into the oil pan. Drain valve The drain valve is located in the oil filter housing under the filter insert, and opens when the filter cover is unscrewed. This ensures a cleaner filter change and less environmental pollution by reducing the amount of residual oil in the old filter. Filter bypass valve (opening pressure 1. 8 - 2. 6 bar) The filter bypass valve is located in the top dome (filter housing) of the oil filter insert. The normal position of the filter bypass valve is closed. If the oil filter insert is clogged, the pressure increase in the filter housing opens the filter bypass valve. This ensures that the engine is lubricated, although the engine oil passing through the bypass valve is unfiltered. Oil retention valve (return flow check valve) The oil retention valve (opening pressure 0. 03 - 0. 07 bar) is placed in the oil filter housing and is intended to prevent the engine oil in the oil ducts from flowing back into the oil pan when the engine is stopped. The oil ducts are therefore always filled with oil. When the engine is restarted, this ensures that components always receive optimal lubrication immediately. Oil spray nozzles The oil spray nozzles are located in the crankcase. There is one oil spray nozzle per cylinder. The oil spray nozzles spray engine oil continuously under the piston crowns to cool them down. Oil is supplied to the oil spray nozzles through the main oil duct. Combination oil temperature sensor/ pressure sensor The oil temperature sensor and oil pressure sensor are located on side of the oil filter housing.

Page 150


Eingine Oil And Filter Change Only change the engine oil with the engine warm! 1. 2. 3. 4.

Unscrew oil filter cap approx. 1cm, filter housing will then train empty. When housing is empty, remove filter from from cap by pressing at the side of the filter Replace o-ring and insert new filter in cap. Tighten cap with specified torque (writen on cap) Drain off the engine oil at the oil drain plug on the oil pan. Fit new sealing ring to the oil drain plug. Screw in the oil drain plug and tighten. Drain plug on oil pan

5. 6. 7. 8. 9.

Sand cast Die cast and plastik

80Nm 60Nm

Pour in the specified quantity and quality of engine oil at the oil filler plug. Mercedes Benz BeVo http://bevo.mercedes-benz.com Start engine Watch the engine oil pressure gauge! It should indicate pressure after several seconds. Do not rev the engine until oil pressure is indicated. Allow the engine to run for 1 - 2 min at idle speed, once the oil pressure is indicated. Wait for about 5 minutes, then check the oil level and adjust if necessary. The waiting time must be observed. Check the oil filter, the oil pan drain plug if necessary, and the long-life oil filter for leaktightness.

Page 151


Notes

Page 152


Crankcase Ventilation System An oil breather is fitted to the valve cover (1), as part of the general plan to cut exhaust gas emissions and help reduce engine oil consumption.

5

1 Blow-by gases pass from the combustion chamber over the piston rings into the crankcase, where they are mixed with tiny oil droplets in the oil vapor. To stop oil vapor escaping into the atmosphere, the vapor is drawn off, cleaned and recycled back to the engine intake side (5). A vacuum diaphragm (2) controls the pressure in the engine oil gallery. Two filter elements (3 & 4) keep the proportion of oil vapor to a reduced level. The oil filtered out is passed back into the oil gallery through a return element integrated with the ventilation system.

Page 153


4

3

Notes

Page 154


Thermostat Installation

The installation location of the thermostat is shown on the right illustration. The circle point to the bleed tab. The bleed tab has to point to the top! The standard thermostat starts to open at 83°C.


Page 155



to charge air cooler

from charge air cooler

Exhaust Air

Page 156


Engine Electronic - Controller (MR)

Parameterization data

Cooler (only series 500 / 460)

Page 157


Engine harness

Plant (ADM)

Structure And Principle Of Operation Of The Engine Control (MR) Short description of the MR engine control module The "MR" engine control module controls the electronic diesel injection system and is intended for engines of the 460, 500 and 900 model series, among others. The main function of the control module is the precise, electrical actuation of the solenoid valves at the unit pumps. To do this, the optimal start of injection and the injected quantity needed for the required torque (or specified rpm in working speed control mode) is calculated and set by the on-board control module, using the performance map and according to the detected engine and ambient conditions. The control module also provides fault detection, emergency mode functions, and diagnoses. Protection/redundancy: The PLD/MR is configured as a 2-computer system, which means that if the host CPU fails, the back-up computer takes over the control of the solenoid valves at the unit pumps. In this case, the engine speed remains constant (about 1300 rpm). The redundant operation (i.e. if one functional component fails, at least one other functional component is available to take its place) applies also to solenoid valves (unit pumps), rpm sensors, starter actuation and the engine CAN bus (single-wire mode capability). The electronic system also has a watchdog circuit, extensive self-tests are performed continuously, and mutual monitoring is performed with the ADM electronics. Engine control: The MR (PLD) engine control system receives guideline values from the drive control (FR) or ADM in the form of 'desired torque' factors. Using these values, the fuel delivery and start of injection at the unit pumps is controlled in relation to a series of performance maps and characteristics stored in the control module, and the actual operating conditions of the engine.

Page 158


Engine Management

The engine control (or engine management) system is divided into two subsystems, each with its own control module. The control module of the ADM subsystem is installed on the vehicle side, and the engine control (MR) subsystem is installed at the engine. Mercedes-Benz engines of the 460, 500 and 900 model series are equipped with an MR electronic engine control. All engine specific data are stored in the MR control module. The MR monitors and defines all the values required for engine operation (for example, start of injection, load condition, ambient conditions, sensor evaluation, etc.). Connection to the ADM is over a single-wire enabled CAN bus, which carries the specified values (required torque, required engine speed, etc.) and actual values (engine speed, coolant, temperature, etc.) in digital form. The ADM control module contains vehicle-related data (among other things), determines the vehicle operating conditions, and allows driver requirements to be transferred to the engine side. These requirements may consist of an accelerator pedal action, application of the engine or service brake, or the working speed control (ADR). From these, the ADM control module determines the required engine torque or engine speed, and sends it as an engine specified torque or specified engine speed by the ADR control to the MR. The ADM monitors and defines certain values required for vehicle operation (legally required speed limitation, maximum working speed, engine brake, etc.). It also provides fault detection, emergency mode functions, and diagnoses.

Page 159


Notes

Page 160


Injection Control Start of delivery The MR/PLD control module controls the start of delivery by means of a time shift of the injection command in relation to the ignition TDC of the cylinder to be filled. It is possible for the MR/PLD electronics to control the start of delivery completely randomly within the mechanical limits (limited by the shape of the cam). The limits for the engine are stored in the control module. The control module recognizes the phase in which each of the individual cylinders is in, by means of the speed sensors (TDC sensor, crankshaft angle position sensor). The second reference mark required for controlling the actual start of injection is obtained from the closing recognition (S). The time lag between the electric and the actual start of injection is compensated for by the map control in the control module.

Page 161


Injection Control Delivery angle The angle by which the crankshaft rotates further when the engine is running from the commencement (S = closing recognition) to the end of a delivery stroke (valve opens), is the delivery angle (A). In this case, the camshaft is rotated only by half the crankshaft delivery angle. The MR/PLD control module determines the period of injection and thus also the quantity injected by means of the delivery angle (pulse width). In diagram 1 the electrical start of injection begins with the closing recognition (S) at 5° before TDC. The delivery stroke ends at 5° after TDC at a delivery angle of 10° crank angle (diagram 2). The actual change in the angle of the crankshaft is detected by the speed sensor at the crankshaft (signal is received every 10°).

Page 162


Delivery Phases Of The Unit Pump Suction stroke

1 Suction stroke During the suction stroke the pump element (1) moves down. As a result of the constant fuel overpressure of about 4 to 6 bar in the fuel low pressure section the high pressure cylinder of the unit pump is filled with fuel through the supply passage (2). 2 Pre-stroke During the pre-stroke the pump element (1) moves up. As valve (3) is not yet closed, the fuel initially is forced into then return flow passage (4).

Pre-stroke

3

3 2

1 4

Fuel feed line Fuel return line

Page 163


4

Delivery Phases Of The Unit Pump Delivery stroke

3 Delivery stroke As soon as valve (3) closes, while pump element (1) moves in the direction of its top dead center, the unit pump is in the delivery stroke. The fuel injection process takes place in the delivery stroke. In this case, the fuel pressure in the high pressure chamber (5) rises to as much as 1800 bar. 4 Residual stroke After valve (3) opens (end of delivery) the fuel pressure in the high pressure chamber (5) is reduced. The remaining fuel supplied by the pump element up to the vertex of the unit pump cam, is again forced into the return flow passage (4).

Residual stroke 5

5

3

3 2

4 1 4

Fuel feed line Fuel return line

Page 164


Notes

Page 165


Sensor Overview Series 500 Start / Stop Coolant temperature sensor

Crankshaft angle position sensor

MR control module

Page 166


Sensor Overview Series 500

Oil pressure Oil temperature

Page 167


Sensor Overview Series 500 Fuel temperature Charge air pressure / temp.

TDC sensor, cylinder 1

Page 168



Oil level sensor

Page 169


Sensor Overview Series 460 Start / Stop

Charge air pressure / temp.

Fuel temp. sensor Crankshaft angle position sensor

Coolant temperature

MR control module

Page 170




Oil pressure / temp.

Page 171





Page 172



Fuel temperature TDC sensor, cylinder 1

Coolant temp. sensor


MR control module

Page 173



Oil temperature

Oil pressure

Page 174


Sensor Overview Series 900 Charge air pressure / temp.

Page 175



Oil level sensor

Page 176


Notes

Page 177


Sensors

1

3

2 4

1

2

3

5 Air

6

Page 178


Oil

1 Oil level sensor 2 Charge air pressure / temperature (Combination sensor) 3 Oil pressure / temperature (Combination sensor) 4 Pressure sensor 5 Temperature sensor 6 Crankshaft angle position sensor / TDC sensor, cylinder 1

Rotational speed, crank angle and TDC detection Principle of the mechanical coupling The position of both rotary sensors "crank angle position sensor" and "TDC sensor, cylinder 1" (camshaft angle position sensor) depends on the mechanical engagement of the camshaft and crankshaft sprockets, which are coupled to each other. With a gear ratio of two crankshaft rotations to one camshaft rotation, one complete working cycle of all cylinders gives a crankshaft reference system of 720°. For signal generation, the following mechanical coupling relative to crankshaft position (° KW) results:

Camshaft BR 500 12 pins for distance of 60° crankshaft +1 additional pin for 55° KW before TDC Camshaft BR 460 and BR 900 12 holes for distance of 60° crankshaft +1 additional hole for 55° crankshaft before TDC Crankshaft BR 460 and BR 500 36 grooves for distance of 10° crankshaft +1 additional groove for 65° crankshaft before TDC Crankshaft BR 900 36 holes for distance of 10° crankshaft +1 additional hole for 65° crankshaft before TDC

Page 179


TDC Cyl.1

Rotary Sensor Crankshaft angle position sensor The sensor placed at the flywheel detects the rotational speed and crankshaft angle by means of 36 symmetrically arranged grooves or holes (1). From the received signal, the electronics also determine variations in crankshaft rotational speed between the individual working cycles and regulates cylinder uniform speed at idle. An additional 37th groove (65° before TDC), depending on the signal synchronization, sends the trigger point for calculating the start of delivery. Cylinder 1 TDC sensor (camshaft angle position sensor) In case of requirement, the sensor placed at the camshaft sprocket sends the rotational speed by means of 12 symmetrically arranged pins. An additional 13th pin (13th hole) (55° before TDC) is needed for signal synchronization, as the trigger point for calculating the start of delivery. Resistance = 1000 - 1385 Ω

Page 180


Temperature Sensor Characteristic NTC

20°C ~ 2,5kΩ

Resistance values of the charge air temperature sensor:

-10°C 7980Ω - 10560Ω +20°C 2280Ω - 2750Ω +80°C 290Ω - 365Ω

Page 181


Oil Level Sensor Function: A sensor probe of about 210 mm in length is screwed into the engine oil pan. The probe is designed so that the measured level is detected from about 100mm. Level measurement is started on terminal 15 when the ignition is switched on. A constant current pulse then passes through the probe for 1.5 seconds and heats a hot wire, thus raising the resistance. At the start of the current pulse, and just before the end, the voltage over the hot wire is measured and the voltage difference compared with a pre-set threshold value. If the temperature increase, and consequently the voltage difference, goes over the pre-set threshold value, then the oil level is too low and the warning lamp is lit on the instrument cluster. The sensor probe is linked with the MR/PLD control module, and over the CAN data bus with the ADM control module, which controls the indicator lamp on the instrument cluster.

Page 182


Notes

Page 183


MR Control Loop The basic operation of the engine control can be represented as a simple control loop. A control loop consists of the controlled system (in this case the engine) and the control device (in this case the control module). The ADM sends the specified value in the form of a preset engine value. The controlled system (the engine) sends the actual value in the form of the value actually present. The MR compares the specified value with the actual value (the conditions actually present). The actual value thus represents the real operating conditions in the engine, as detected by the various sensors. In the comparison, if the actual value is found to be higher than the specified value, the injection control reduces the injection quantity. If it is found to be lower, the injection control raises the injection quantity. Thus, the actual value is continuously compared with the specified value.

Page 184


Engine Control Parameterization For ordering a new engine control electronic system, the required parameters are found on the model plate. Legend: 1 = MB number and data record number 2 = Certification No. 3 = Engine number 4 = Device code For ordering a new MR control module, the required data can be read out of the old MR with Minidiag 2.

Page 185


MiniDiag 2

1 Power supply ( 12 V – 24 V) 2 25 pin connector 3 Messuring pin

Page 186


Engine Tests

Compression Test

Inspection for mechanical wear, or defects on individual cylinders (gas seal). e.g.: erratic engine operation.

Localisation of defective cylinder Individual cylinder shutdown (gas seal or injection) e.g.: erratic engine operation Idle balance control: Correction

Localisation of defective cylinder (gas seal or injection) e.g.: erratic engine operation

Voltmeter

Complementary electrical tests on current path and component

Check speed sensor for reverse polarity

Poor engine start and extremely erratic engine operation following repair

Page 187


Notes

Page 188


ADM-X

Page 189


ADM - X Mercedes-Benz engines of the 500, 900 and 460 model series are equipped with an MR electronic engine control. The MR monitors and defines all the values required for engine operation (for example, start of injection, load condition, ambient conditions, sensor evaluation, etc.). Connection to the vehicle is through a CAN interface, which carries the specified values (required torque, required engine speed, etc.) and actual values (engine speed, oil pressure, etc.) in digital form. The adaptation module as vehicle control (ADM-2) possesses the CAN interface required for the MR, and allows driver requirements to be transferred to the engine side. The ADM-2 allows the use of conventional display devices, while also providing the conventional interface for special functions. Switch signals allow the selection of operating statuses pre-defined in the engine control, for example torque and engine speed limits, or the specifying of predefined rpm values. By parameterization, the routines stored in the control module can be adapted optimally to the type of application. A diagnostic interface is provided for connecting external diagnostic equipment. The ADM-X is connected to an SAE J 1939 CAN bus (high-speed CAN bus) and an additional diagnosis CAN bus. Important! The ADM-2 parameters should only be changed after obtaining the approval of the engine installer! Note: There is an operator's manual for the ADM-2, which gives a description of the possible functions, inputs/outputs, required parameter settings, and fault codes.

Page 190


Notes

Page 191


Special Tools

Adapters for fuel system check (all series) 541 589 00 91 00

Sleeve for o-ring installation (unit pump series 500 / 460) 541 589 01 14 00

Page 192


Extractor for sealing sleeve (Injector) (all series) 906 589 02 63 00

Sleeve for o-ring installation (unit pump series 900) 904 589 00 14 00

Barring device (series 500 / 460) 407 589 00 63 00

Barring device (series 900) 904 589 04 63 00

Special Tools

Extractor (all series) 355 589 01 63 00

Manometer for adapterset 541 589 02 21 00

Page 193


Socket 19mm 422 589 02 09 00

Pump for initial oil filling 352 589 11 63 00

Socket 17mm 422 589 01 09 00

Adapter for oil filling pump 541 589 02 63 00

Special Tools

Assembly jig for sealing sleeve 906 589 03 63 01

Page 194


Adapter compression test 904 589 01 21 00

Notes

Page 195


Training Doc Mercedes 900

Recommend Documents