01 Engine System LG956L

LG956L Training material Chapter 3 Engine System

Chapter 3 Engine System

Section 1 overview of engine 1 Model meaning 2.Characteristic of engine Section 2 Crank-link mechanism 1.Engine block group 2.Crankshaft flywheel group 3.Piston rod group Section 3 Valve mechanism 1.Overview 2.Main composition of valve mechanism Section 4 Fuel supply system 1.Overview 2.Fuel injection pump 3.Regulator 4.Fuel delivery pump 5.Fuel injection 6.燃油水寒宝 7.Fuel filter

第&页总共205页 1

Section5 Lubrication system 1.Function 2.Method of lubrication 3.Main spare part Section 6 Cooling system 1.Function of cooling system 2.Main spare part of cooling system Section 7 Air intake and exhaust system 1.Function of air intake and exhaust system 2.Working principle of air intake and exhaust system 3.Parts of air intake and exhaust system Section 8 Common failures 1.Start unsuccessfully engine 2.Underpower of engine 3.Exhaust black smoke 4.Exhaust white and blue smoke 5.Low lubricating oil pressure 6.High lubricating oil pressure 7.High lubricating oil consumption 8.High coolant temperature RELIABILITY IN ACTION

Section 1 Overview 1、、Introduction of the meaning LG956L is equiped with Weichai engine which is in-line, four-

WD10G220E23

stroke, water-cooled, turbocharged six-cylinder diesel engine, the engien model number is

Water Diesel

10

Displacement Code (Displacement is 10L.)

G

Construction machinery

220

Power(220ps)

E2

State three emission standard

3

Variant code

WD

WD10G220E23, the meanings of the words and numbers see the right table.

RELIABILITY IN ACTION 2

Section 1 Overview 2、Characteristics of the Weichai

engine（WD10G220E23）： 1、High reliability, long life Using the tunnel structure, the crankcase and the seven main bearing cap are forged as one piece by high-quality alloy steel, nitrided crankshaft and connecting rod, and strength bolts with flexible design, to ensure the high reliability of the engine moving parts. Reasonable design of the high power function of the camshaft profile can make the engine distribution system has higher reliability and lower mechanical vibration noise. Characteristics of the use of construction machinery are fully considered,


Section 1 Overview 2、、Powerful engine、、large torque reserve Using the imported Ps3000, Ps7100 fuel injection pump with low inertia porous injector, through fuel supply characteristics correcting and efficiency turbocharger proper matching can achieve a good dynamic and make the torque reserves reach more than 20%, to provide strong horsepower for all kinds of engineering machinery.

3、、Good economy Three new structures of piston rings, best matching cylinder clearance, equiped with new type of combustion chamber and the best swirl ratio, overlapping curve is honed on the cylinder plate form to aviod leakage, ensure a more perfect geometry of cylinder bore, and reduce the consumption of fuel and oil, the lowest fuel consumption of the turbocharged engine reaches 194g/kW.h, , oil consumption less than 0.5g/kW.h.


Section 1 Overview 4、、Powerful engine、、High torque reserve The exhaust can meet the Euro II emission standard, which are well suited for working in limited space such as tunnels, warehouse, cabins, etc.

5、、Good ability to adopt the plateau The new type of turbocharger has a function of air intake reflow, which can broaden the scope of the diesel engine high effiency workspace, compensate for the power loss in plateau, and can provide good adaptability in plateau.

6、、Good low temperature start The cold starting device is added to ensure the engine can start smoothly at 40 ℃. RELIABILITY IN ACTION 5

Section 2 Crank and connecting rod mechanism

Crank and connecting rod

mechanism

Piston rod assembly

1、、Basic components

The crank and connecting rod mechanism mainly consists of three parts: the body assembly, crankshaft flywheel assembly, piston and connecting rod Engine body assembly

assembly.

Crankshaft flywheel assembly


Section 2 Crank and connecting rod mechanism Crank and connecting rod mechanism 2、、Main function The crank and connecting rod mechanism is the main parts of the reciprocating piston engine to transfer the heat energy into mechanical energy, which function is to transfer the pressure on the piston crown acted by the gas to the rotational torque of the crankshaft, and output to the external. Most of the power is tranmitted to the outside through the flywheel, another portion is through the gear and idler gear of the front end of the crankshaft to drive other mechanisms and systems of itself, primarily to withstand high temperature, high pressure, chemical corrosion and the impact of inertia force.


Section 2 Crank and connecting rod mechanism 1、、The cylinder block assembly It is mainly composed of the cylinder block, cylinder liner, cylinder head, cylinder gasket, oil sump, engine mounts and other mechanical components. （1））Cylinder block ① Function The cylinder block is a basic installation for each mechanisms and systems, which is used to maintain the precise positional relationship between each moving parts of the

General form

General type

engine. The cylinder block is usually forged together with crankcase as one piece, so called cylinder-crankcase.

characteristic

Application

General

The lower surface of the cylinder block and the axis of the crankshaft are on the same plane, the stiffness is small

Cars, small trucks

Gantry

The lower surface of the cylinder block is below the axis of the crankshaft, the stiffness is larger

Medium and heavy trucks

Tunnel

Main bearings are not separated (equipped with modular crankshafts), the stiffness and weight are the largest

large mechanical loadload of diesel engine

different position of the installation

the oil pan, the cylinder block is usually divided into three types: general crankcase, crankcase and gantry tunnel

Tunnel form

FORM

② Structure According to the

planes between the cylinder block and

Gantry form

crankcase. RELIABILITY IN ACTION 8

Section 2 Crank and connecting rod mechanism （1））Cylinder block ③ The structural style of the LG956L Weichai engine The cylinder block of the Weichai WD10G220E23 engine is the tunnel structure, the main bearing cover and the crankcase forged toghther in one piece,the crankcase and the cylinder block are separated by the centerline of the crankshaft, the upper part is the cylinder block, the lower part is the crankcase, the crankcase and the seven main bearings together form a integrated framework with good stiffness. This tunnel structure not only has a good stiffness, and can use the sliding bearings to reduce the noise and improve the service life.


Section 2 Crank and connecting rod mechanism （1) Cylinder block ④ Precautions for the installtion of the Cylinder block and crankcase The WD10G220E23 engine has no gasket between the crankcase and cylinder, the bottom of the cylinder block should be coated smoothly with 510 sealant, which will lower the oil pressure, the sealant does not need too much, and installation should be implemented immediately after the coating finished. Notice: The cylinder block and crankcase are required to be installed in pairs, which are not interchangeable. When one of the parts is damaged, both parts should be replaced, optional installation is not allowed.



（2））Cylinder liner ① Function The main function of the cylinder liner is to guide the piston direction and seal the gas inside the cylinder.

② Classification of cylinder sleeve There are two types of cylinder liners: Dry cylinder liner and wet cylinder liner, Wet cylinder liner

the dry cylinder liner is not directly in contact with the cooling liquid, but the

Form

Characteristic

Advantage

Aisadvantage

Demand

Wet cylinder sleeve

The outer surface is in direct contact with the cooling

Cooling effect, casting convenient, easy disassembly

Poor rigidity, easy leakage(water and gas)

With upper and lower positioning belt and lower bearing seal tape

Dry cylinder sleeve

The outer surface is not in direct contact with the cooling water

wet cylinder is just the opposite. Weichai WD10G220E23 diesel engine uses the thin-walled dry cylinder liner.

Dry cylinder liner

（Contrary to the above））

With upper and lower positioning belt


Section 2 Crank and connecting rod mechanism （2））Cylinder sleeve ③ Precautions for the installtion of Weichai WD10G220E23 diesel engine cylinder liner Use alcohol or Loctite 755 to wash the grease off the cylinder hole and the cylinder liner external surface before installation, then apply a thin layer of molybdenum disulfide powder on the surface of the cylinder liner external surface, and finally, use hands or tools to pressure the cylinder liner into the cylinder block. Check the cylinder liner is 0.020.07mm above the upper surface of the cylinder block after the cylinder liner pressed into the cylnder block.


RELIABILITY IN ACTION

Section 2 Crank and connecting rod mechanism Cylinder head （3））Cylinder head ① Function The main function of the cylinder head is to seal the upper part of the cylinder, and form a combustion chamber with piston

Integral-type

crown and cylinder wall. ② Type of cylinder head The cylinder head has common types of integral-type, single-

Double-cylinder split type

form

characteristic

application

integral

Poor rigidity, easily deformed by heat or pressure, which will influence the seal, the whole block must be replaced when damaged.

old-fashioned engine

cylinder split type and double cylinder split type.

Single-cylinder split type

one cylinder per block split

two cylinder per block

easy to be made or repaired, good rigidity

wide application

three cylinder per block RELIABILITY IN ACTION 13

Section 2 Crank and connecting rod mechanism （3））Cylinder block ③ The cylinder head of Weichai WD10G220E23 engine adopts the structure with one cylinder and one cover, good manufacture technics, and easily disassembled and transported. Each cylinder is fixed by four M16 bolt, and two adjacent cylinder head simultaneously pressed together by three M12 stud with a clamping block, which increases the engine rigidity.



Section 2 Crank and connecting rod mechanism 2、、The piston and connecting rod assembly The Piston and connecting rod assembly is mainly composed of piston, piston ring, connecting rod, piston pin and other mechanical components. 1-piston 2-Spiral spring-loaded oil ring（oil ring） 3-cone ring（Compression ring） 4-ladder ring（Compression ring） 5-connecting rod sleeve 6-connecting rod 7-connecting rod cover 8-connecting rod bolt 9-connecting rod bush 10、11connecting rod bush 12-retaining ring


Section 2 Crank and connecting rod mechanism （1））Piston ① Function of piston The main function of the piston is designed to withstand the pressure from buring air, and transmit the force through the piston pin to the connecting rod to push the crankshaft rotate. The piston head forms a combustion chamber with cylinder head and cylinder wall. ② Structure of piston The basic structure of the piston can be divided into three parts: the crown, the head and the skirt. The piston head forms a combustion chamber with cylinder head and cylinder block, bear force generated by the air

1－－top；；2－－head；；3－－skirt；；4－－land；；5－－ring groove；；6 －pin boss；；7－－ reinforcing rib ；8－－ Snap ring groove ；9 － Oil discharge hole and Oil discharge groove；；

pressure in the cylinder, and transmit the force through the piston pin to the connecting rod to push the crankshaft rotate.


Section 2 Crank and connecting rod mechanism The piston head is the upper part above the piston ring groove, which function is as follows: A: Withstand the air force and transmit it to the connecting rod. B: Working together with the piston rings to realize the cylinder cealing. C: Transmit the heat absorbed from the piston head to the cylinder wall by passing throught the piston ring. The piston skirt is the lower part of the engine from the oil ring groove down to the bottom, which function is to guide the piston reciprocated in the cylinder

1－－top；；2－－head；；3－－skirt；；4－－land；；5－－ring groove；；6 －pin boss；；7－－ reinforcing rib ；8－－ Snap ring groove ；9 － Oil discharge hole and Oil discharge groove；；

and withstand side pressure.



③ The structure and characteristics of the Weichai WD10G220E23 engine piston A：The piston is made of aluminum alloy, the specific weight is small, and the thermal conductivity is very good. B

：The top of the piston has a S - shaped

combustion chamber, and a pit which can avoid the valve, in additional, combustion chamber and avoid the valve pit, while the product code is on the piston top. C: Piston top shore (also known as fire shore) processes a thin annular groove, called back slot, which has the function of collecting dirt and proventing occlusion, and can improve the running state between the top of the piston and the cylinder.

D：The piston can be grouped by weight, the difference between each group is not more than 10g, the marks of these groups are G1 G3

、 G2、

、G4、G5. When replacing the piston, the

weight of the pistons on the same machine should be the same. E

：Engine oil should be applied before the

piston installation, the opening of the piston rings should be staggered 120

°,

and angle between

the opening of the first ring and the edge of the 18 piston pin hole should not less than 30

°


Section 2 Crank and connecting rod mechanism (2) Piston ring ① Classification Piston ring is a resilient split ring, which can be divided into compression

Compression ring

ring and oil ring.

② Function of compression ring The first and second rings are called compression ring, which function is to ensure the seal between the cylinder and the piston, prevent the gas leakage, and transmit most of the heat absorbed from

Oil ring

the piston crown to the cylinder wall.

③ Function of oil ring The third ring is oil ring, which function is to distribute oil, scrape oil, reduce the friction resistance and assist the sealing.


Section 2 Crank and connecting rod mechanism (2) Piston ④ Sealing principle of Gas ring has a slot, and is flexible, which outer diameter is greater than the cylinder diameter in free state, when installed into the cylinder together with the piston, the outer surface set close to the cylinder wall to form the first sealing surface, the sealed gas can not get throught the space between gas ring and the cylinder, but enter the space between ring and ring groove, on one hand, it can press the ring to the surface of the groove to form the second sealing surface, on the other hand, the pressure acting on the back of the ring can greatly enhance the sealing effect of the first sealing surface.The gas ring sealing

First sealing face

second sealing face

effect is generally related to the number of the gas ring, WeiChai diesel engine has 2 gas rings.


Section 2 Crank and connecting rod mechanism (2) Piston ring

⑤ Type of the compression ring section Rectangular ring ：Simple technical process, good thermal conductivity, but the oil pumping phenomenon is easy to occur, which will cause the carbon deposition. Twist ring

：The torque M is generated by the

left-right asymmetry, which can make the edge of the rings to contact with the upper and lower

Rectangular ring

Taper face ring

surface of the groove, prevent oil pumping, and

Twist ring

increase seal. Taper face ring

：Scrap the oil downward,

and

float on the oil film when slide upward,which can reduce the mechanical wear, but the cone angle is hard to be made. Keystone ring

：The ring side clearance is

changed according to the changes of the direction

Twist ring

Keystone ring

Barrell face ring

of the side pressure, which can squeeze the carbon deposition out of the ring groove, but the technical process of the upper and lower surfaces are more complicated. Barrell face ring

：Good contact can increase

sealing, but the convex surface is hard to be made. 21


Section 2 Crank and connecting rod mechanism (2) Piston ring ⑥ Compression ring pump oil piston

Function：：Good for cylinder

piston

lubrication. Harm：：Large lubricating oil Cylinder

Cylinder

consumption, easy to form carbon deposition in the ring groove, which will caused ring stuck in the groove and lose the sealing effect, scratch the cylinder wall, and even break the ring. Measure：：Reduce the ring quality, change the shape of the ring section, and use the combination oil ring.


Section 2 Crank and connecting rod mechanism (2) Piston ring

⑦ Oil ring Function：The main function of the engine oil ring is is to distribute oil, scrape oil, and play an assistant role to sealing the gas, which can be divided into two types, common oil ring and combination oil ring. A: General oil ring The general oil ring is also called integral oil ring, with a groove machined in the middle of the outer cylindrical surface of the ring, and a hold

General oil ring

or a slot drilled in the groove, when the piston moves downward, the excess oil will be scraped off the cylinder wall and flow back to the crankcase through the small hole or slot. B

：combination oil ring

The combination oil ring is composed of a pair of upper and lower side rail rings and a

Combination oil ring

Combination oil ring

middle dilator, the side rail ring is made of chrome-plated steel, the perimeter of the dilator is slightly larger than the internal circumference

Function of oil scraper ring

of the cylinder, which can tightly press the side rail ring against the cylinder wall, and the scraping effect is obvious.


Section 2 Crank and connecting rod mechanism （2）piston ring

⑧ The structure and characteristics of Weichai WD10G220E23 engine piston rings First ring

：The surface of the double sided

trapezoid tubbish ring is treated by means of phosphating treatment, with a notch and an installation marking "TOP"on the upper part; The work surface is sprayed with molybdenum layer, which will help to increase the effect of wearing resistance and anti galling.

：Cone ring, the cone angle of the torus is 90 ° ± 5 ', the surface is treated by Second ring

means of oxidation treatment, the work surface is sprayed with chromium layer, and the upper part of the ring has a installation marking "TOP" Third ring

：The internal expanding circle

combined oil ring is made of cast iron, has 12 blades, double-edged surface chrome plated, lined with spiral springs, which has the characteristics of small abrasion, good oil seal and scraping effect, stable performance, durable and so on.


Section 2 Crank and connecting rod mechanism （3））piston pin

① Function ：

Connecting the piston and connecting rod, transfering the force between the two parts.

② Structure ：

Hollow cylinder.

③ Material：

Alloy surface carburization (surface hardness increased)

④ Assembly Connecting rod head

Full floating—The pin rotates freely and wear evenly in the pin hole and connecting rod

Snap

bushing, the inner of both ends of the pin seat has

ring

Connecting rod sleeve Piston pin

clip rings. Half floating—The the floats in the pin seat,

Piston pin seat

which is connected with the small end of the connecting rod by bolts. Notice 90

：Heat the aluminum pistons in the 70～

℃ water or oil before installing the pin into

the piston to ensure the combination between the pin and the pin seat hole in the cold state is a

Full floating assembly

Half floating assembly

transition fit .


Section 2 Crank and connecting rod mechanism （4））Connecting rod ① Composition T h e c o n n e c t i n g r o d i s c o mp o s e d o f

Connecting rod small end

connecting rod small end, shaft, connecting rod big end, screw and connecting rod cap,etc.

② Function Connect the piston with the crankshaft, transfer the force from piston to crankshaft, and

Connecting rod

transfer the reciprocating movement of the piston

shank

into the rotary movement of the crankshaft.

③ Classification Generally, the engine connecting rod can be divided into two types, the equal type and the oblique fractional type.

Connecting rod

Weichai WD10G220E23 engine adopts the

large end

oblique fractional rod.

Inclined cut


Section 2 Crank and connecting rod mechanism （4））Connecting rod ⑤ Connecting rod of weichai engine(WD10G220E23) A: Weichai WD10G220E23 engine connecting rod big end is the oblique incision type,split by 45

°oblique, using the 60°teeth to locate the

combined surface, with characteristics of positioning accuracy, combined tightly, etc. B

：The weight of the connecting rod is divided

into 9 groups which are respectively marked by C, D, E, F, G, H, J, K, I, the quality of each level is no more than 29g, when replacing the connecting rod, make sure the marked letter is the same, otherwise it will cause the diesel engine to produce abnormal vibration.

：

C The connecting rod and connecting rod cover must be processed as a whole set, marked the same number, and are not interchangeable. The connecting rod bolts can only be used once.



Section 2 Crank and connecting rod mechanism （5））Bearing shell A tile form of sliding bearing is mounted in the connecting rod big end hole to reduce friction and the wear of connecting rod journal of the crankshaft, which is called connecting rod bearing. The bearing shell is divided into upper and lower shell, which is currently use the thin-walled rigid bearing, with wear-resistant alloy layer casted on the internal surface. Function of the connecting rod bearing shell：： Bearing, heat conduction, protecting the big end connecting rod and reduce the wear.

1-steel backing

2-oil groove

3-locating tang

4-antiwear alloy layer


Section 2 Crank and connecting rod mechanism 3、、Crankshaft flywheel assembly Mainly consists of crankshaft, flywheel and other accessories.



Section 2 Crank and connecting rod mechanism （1））Crankshaft ① Composition The crankshaft is composed of main journal, connecting rod shaft neck, crank, counterbalance, front-end and back-end, etc. A connecting rod shaft neck and a crankshaft constitute a crank. ② Function The crankshaft interacts closely with Main journal the connecting rod to change the gas

crankshaft

Connecting rod journal

pressure into rotation power, transfer the force to the transmission mechanism, and drive the valve mechanism and other auxiliary devices.

collar


Section 2 Crank and connecting rod mechanism （2））Flywheel Function: Depending on the flywheel inertia to keep the engine running balance, and help engine to overcome short time overloading.

Material: High strength, wear-resistant material (Grey cast iron)

1－－flywheel； 3－－bush；；4－－bolt；；5 －support；7 －gear ring； 8 －flange；


Section 2 Crank and connecting rod mechanism （3））Absorber In the process of engine working, each cylinder has its own working stroke, the magnitude and direction of the force transfered from the connecting rod to the crank pin are changed periodically, the exciting force caused by the periodic variation acts on the crankshaft to cause the the instantaneous angular velocity of the crank is also changed periodically. But the flywheel fixed on the crankshaft has a big rotary inertia, which can be regarded to do uniform rotation, so at one moment the crank speed is faster than the flywheel and the next the crank speed is slower than the flywheel, which can form a torsional oscillation against the flywheel, such is the crankshaft torsional vibration. When the ratio of the excitation frequency to the natural frequency of the crankshaft is an integer,

1－－Absorber； Absorber；

2－－Pulley；；

3－－Bolt；；

the crankshaft will produce resonance.

：Reduce the vibration, avoid

Function

resonance Principle

：Friction in the damper gradually

consumes the energy of the crankshaft torsional vibration to gradually reduce the amplitude.


Section 2 Crank and connecting rod mechanism （4））Six cylinder engine crank layout Principle：： 1.The firing interval should be uniform to ensure that the engine is running smoothly. 2.The two continuous working cylinders

1-6

should be as far as possible（To reduce the load of the main journal, and avoid the overlap of the air influences the air intake.）

5-2

3-4


Section 2 Crank and connecting rod mechanism （5）Firing order of six-stroke engine The four stroke inline six cylinder engine firing angle is 720/6=120 °, six

Crank corner （°）

cranks are respectively arranged on the

0~60

three planes, the firing order is 1-5-3-6-

60~120

2-4. T h e c y l i n d e r o f t h e We i c h a i WD10G220E23 engine, near the fan, is the first cylinder.

Cylinder 1

Cylinder 2

Cylinder 3

Cylinder 4

Cylinder 5

Cylinder 6

exhaust

intake

power

compre ssion

intake

power compre ssion

120~180 intake

180~240 240~300

power

exhaust power

300~360 360~420 420~480

intake

exhaust power exhaust

660~72 0

compre ssion

power

540~600 compre ssion

compres sion

intake

compre ssion

480~540

600~660

exhaust

intake exhaust

exhaus t

intake

power

compr ession


Section 3 Valve mechanism 1、、Overview The function of valve mechanism is to control

7 the air inlet and outlet, which regularly controls the opening and closing of the intake and exhaust valve, supply mixture fresh air to the cylinder

6

and timely draw used air out according to the requirement of the cylinder working order and working process. In addition, when the inlet and

5

outlet valve closed, it can ensure the cylinder seal. When the engine works, the camshaft is driven by the crankshaft through the timing gear,

1

the cams push the tappet and rod and pass the action to the rocker arm which rotate around an

2

axis to overcome the spring force to push the valve moves down and be opened. When the

4

camshaft continue to rotate and cross the

3 maximum pushing process, the valves will return to the original position and be closed. 1-pushrod

2-tappet

3-camshaft

4-valve

5-valve spring 6-locking plate 7-rocher arm


Section 3 Valve mechanism 2

、Main composition of valve mechanism

The valve mechanism is maily composed of Valve assemb ly and valve tr ansmissio n assembly. 1

、Valve group

Valve spring retainer

The valve assembly includes valves, valve seats, valve guides, valve springs, locking plate and retainer.

Locking plate (1) Valve The function of the valve is to control the opening and closing of the inlet and outlet valve,

Snap ring resist high temperature, high pressure and impact, require the valve to have the following characteristic: sufficient stiffness, strength, wear resistance, high temperature resistance, corrosion resistance, impact resistance. (2) Valve guide It's function is to guide the valve, ensure the valves do straight reciprocating motion. In adition, it has the function of heat transfer, pass heat from the valve head to the rod shaft, and spread out through the cylinder head.

Valve spring Valve cone angle

valve


Section 3 Valve mechanism （3））valve seat The valve seat interacts closely with the valve head sealing conical surface to seal the cylinder,

Valve spring retainer

and the heat from the valve head can be transmitted to the outside through the valve seat.

（4））valve spring

Locking plate

The function of the valve spring is to ensure the valve's return, prevent the transmission parts detachment during movement. When the valve

Snap ring

closed, the valve spring should ensure the seal between valve and valve seat. when the valve opened, it should ensure the valve can't be separated from the cam by the inertial force created during the movement. The valve spring is a cylindrical spiral spring, one end is supported on the cylinder head and the other end is pressed against the spring seat which is at the end of the valve rod, the spring seat is fixed to the end of the valve rod with a locking plate.

Valve spring Valve cone angle

valve


Section 3 Valve mechanism 2、、Valve transmission assembly The valve transmission assembly transfers movement between camshaft and valve, which includes camshaft, tappet, push rod, rocker arm, valve clearance adjusting screw and other components.

（1））Camshaft The camshaft controls the opening and

Cam shape

Air intake (exhaust) cam angle

closing of the valve, each intake valve and exhaust valve respectively has corresponding

Push rod

intake cam and exhaust cam, the valve opening and closing time and height can be influenced by the rotation of the cam, the cam arrangement influences the opening and closing time of the valve and working order. The cam has two types, the inlet cam and outlet cam, the number of cams is the same as the number of inlet and outlet valves. For each

SixSix-stroke engine camshaft Rocker arm

working cycle, the crankshaf will turn two

tappet

cycles, and the camshaft will turn one cycle. 360/60=60

°。

The angle between the same name valves for each cylinder is 360/60=60 38

°


Section 3 Valve mechanism （2））Tappet The function of the cam tappet is to transmit the thrust from the cam to the push rod, and bear the lateral force exerted by the rotation of the camshaft. （3））Pushrod The function of the push rod is

to

Cam shape

Air intake (exhaust) cam angle

transmit the thrust from the camshaft to the rocker arm, which is the most easily Push rod flexible parts of the gas distribution mechanism （4））rocker arm and seat The function is to transmit the thrust from the tappet and push rod to the rocker arm to push the rocker arm swing to open and close the valve.

SixSix-stroke engine camshaft Rocker arm tappet


Section 3 Valve mechanism 3、、valve clearance ① definition Valve clearance means the clearance between the end of the valve rod and rocker arm or tappet when the valve is completely closed under the cold condition. ② function：： The function is to compensate for the amount of expansion after the valve is heated. Different models have different size of valve clearance, the exhaust valve clearance is larger than the inlet valve clearance in common cold state.


Section 3 Valve mechanism 、valve clearance ③ Valve clearance is too large or too small 3

will cause certain harms: If the valve clearance is too large, which will cause the the open of the inlet and exhaust valve delayed, the exhaust time shortened , the valve opening height reduced, and the normal gas distribution phase changed , result in insufficient air intake and incompletely air exhaust, parts of the gas distribution mechanism impact increased and wear accelerated. If the valve clearance is too small, when the parts heated and expanded,

WD10G220E23 engine intake and exhaust valve clearance （cool state） state）

Intake valve

Exhaust valve

0.3mm

0.4mm

which will push the valve open, cause the valve can not be tightly closed to prevent the gas to be released, reduce the engine power, result in serious carbon deposition or burn, and even the valve strike the piston. The Weichai WD10G220E23 engine air intake valve clearance(cold machine) is 0.3mm and the exhaust valve clearance is 0.40mm。


Section 3 Valve mechanism 3、、valve clearance ④adjustment and inspection of valve clearance 1）Using the 13mm socket wrench to remove the 6 cylinder head cover.

2）Use the 32mm Crank Wrench to slowly rotate the diesel engine, adjust the tick mark on the flywheel house point to the OT mark and the piston of the first cylinder point to the compression top dead center(The inlet and exhaust valves of the first cylinder are closed.) The first cylinder is from the fan end.


Section 3 Valve mechanism 3、、Valve clearance ④ Adjustment and inspection of valve clearance 5

）Take the intake and exhaust valve

clearance

with

a

feeler

Intake valve clearance: 0.3mm Exhaust valve clearance:0.4mm Notice: When measuring the valve clearance, the accurate value is taken under the condition that the diesel engine should be in

℃

a cold state(lower 60 ), and there should be a obstacles sticky feeling as the feeler slides between the valve lifter and the rocker. 6

）When adjusting the valve clearance,

first unscrew loosen the locknut and the adjusting bolt, and then place the required thickness feeler between the rocker arm and the valve, tighten the adjusting bolts, and then tighten the lock nut.


Section 3 Valve mechanism 3、、valve clearance ④adjustment and inspection of valve clearance 7

）Rotate the engine until the first cylinder

to the compression top dead center, adjust the clearance of the intake and exhaust valve of the first cylinder, the intake valve of the second cylinder, the exhaust valve of the third cylinder, the intake valve of the fourth cylinder, the exhaust valve of the fifth cylinder, the sixth cylinder should not be adjusted. See right picture(I means the air intake, E means the air exhaust). 8

）Keep on rotating the engine until the

sixth cylinder to the compression top dead center, then adjust the other valve clearance which have not been adjusted in the seventh adjusting step.


Section 3 Valve mechanism 4、、valve phase

（1）Intake valve early opening and late closing： Enlarge the valve opening height at the beginning of the air intake stroke, reduce the air intake resistance, and increase the air intake quantity. Intake valve late closing

：

Delaying the intake time, and increasing the air intake q uantity und er the effect o f the atmospheric pressure and the gas inertia force. Exhaust valve open early

：

The cylinder can exhaust the gas by itself with the help of the high pressure in the cylinder, which can reduce the exhaust resistance,and ensure the gas discharged cleanly. Exhaust valve close late

：

Extending the air exhaust time, and ensure the air completely discharged the pressure and inertia force of the exhaust air.


Section 3 Valve mechanism 4、、valve phase

Valve phase

（2））valve overlap As the inlet valve opens early, the exhaust

Compression process

valve closes late, the inlet valve opened before the upper dead point, while the exhaust valve closed after the upper dead point, which

Working process

inevitably cause the phenomenon of two valves opened at the same time, in this case the valve angle will be overlapped, when two valves opened at the same time, the corresponding crank angle is called the valve overlap angle.

（ 3 ） Ai r

a c t ua l i ntake and exhaust valve

opening, closing and duration time.

Exhaust process

Intake process

The actual air intake and duration time: At the end of the air exhaust stroke, the piston reaches the upper dead point, when the crankshaft turned to a position where the angle between the crankshaft and the upper dead point is a, the inlet valve begin to open, and will be closed until the piston accross the bottom dead point.


Section 3 Valve mechanism 4、、valve phase （3））Air actual intake and exhaust

Valve phase

valve opening, closing and duration time.

Compression process

The actual time and duration of the air intake. Working process The duration of the entire intake process is equivalent to the crank rotation angle: 180 ° + α + β. α: Intake advance angle, generally α = 10-30 β: Intake lag angle， generallyβ=40Exhaust process

Intake process

80° Weichai WD10G220E23 engine: Exhaust advance angle α =34°～ 39° Exhaust lag angle β =61°～ 67°


Section 3 Valve mechanism

、valve phase （3）Intake and exhaust valve opening 4

Valve phase Compression process

and closing time and duration. The actual time and duration of the air intake. When the working process is closing to the

Working process

end, and the piston angle before the bottom dead point is γ, the exhaust valve opens. When the piston passes the up dead point, and the after angle is δ, the exhaust valve is closed. The crankshaft rotates 180

°+ γ+ δ

during the whole process. γ:exhaust advance angle

°

80

δ:Intake lag angle

，generally γ =40-

Exhaust process

Intake process

，generally:δ =10-30°

Weichai WD10G220E23 engine:

°～ 81° Intake lag angleδ =26 °～ 34° exhaust advance angle γ =76


Section 4 Fuel supply system

High pressure pipe

Oil injector

1.overview (1) composition of fuel supply system The fuel supply system consists of injection pump, fuel supply pump, fuel filter, injector, high pressure oil pipe, low pressure oil pipe and other accessories.

（2）function of fuel supply system The main function of the fuel supply system is to continuously feed the engine with filtrated clean fuel, and inject certain amount of diesel into combustion chamber as certain pressure and

quality according to

different engine performance requirements, which will mix and burn with the air rapidly .

Fuel supply system consists of fuel

injection pump, fuel delivery pump, fuel filter, fuel injector, high pressure oil pipe, low pressure oil pipe and accessories.

High pressure pump

Low pressure pipe

Fuel filter


Section 4 Fuel supply system 1.overview

（3）working process of fuel supply system The engine rotation is transfered from the

coupling or drive gear to the injection pump camshaft through the advance device. The camshaft rotation drives the fule delievery pump suck oil from the fuel tank, the filter clean oil will be delivered to the plunger through fuel channel in the fuel injection pump, the plunger will move upward through the cam shaft rotation, the piston, the fuel pressure will increased to a high pressure, and the fuel oil will flow into the injector nozzle through the high pressure oil pipe and the injector. When the pressure of the fuel oil delivered to the injector nozzle reaches above the specified starting injection pressure of the injector, the oil will be sprayed into the engine combustion chamber in the form of mist. The overflowed or left fuel oil of the fuel injector and fuel injection pump will flow back to the fuel tank through their respective fuel pipe.


Section 4 Fuel supply system Injection pump

2.Oil injection pump

（1）function of injection pump

high pressure fuel pump

The main function of the fuel injection pump is to supply certain amount of high pressure fuel to the injector in regulation time

，while at the same

time accomplishing the engine rotary speed control.

（2）basic demand of injection pump ① The fuel pressure should ensure

the

requirement o f t h e injection pressure and atomization quality.

②

The fuel supply should meet the exact

amount of fuel required by the diesel engine.

③ Ensure the diesel engine working order and

accurate fuel supply within the given time.

④ The amount of fuel supply and fuel injection

timing could be adjusted to ensure each cylinder oil supply evenly.

⑤ The fuel supply regulation should ensure the

diesel fuel burned completely.

⑥ The beginning and ending of the oil supply

oil return pipe

connector

Injector assembly

must act quickly, the oil cut off must act swiftly to avoide oil drip.


Section 4 Fuel supply system (3)working principle of injection pump ①oil intake process The plunger will move downward under the force of spring after the cam convex portion turned over the highest position， which will creat vacuum in the plunger upper space (called the pump oil chamber), when the hole on the plunger sleeve opened by the plunger upper end, the diesel fuel in the oil channel of the pump upper space will enter the the pump oil chamber through the oil inlet, when the plunger moves to the bottom dead center, the oil inlet progress ended.



（3）working principle of injection pump ②oil supply process When the camshaft turned to the cam convex portion and lift up the roller body, the plunger will move upward under the force of the spring, the diesel oil will be compressed, and part of the fuel will return to the upper oil chamber of the injection pump through the oil hole. When the plunger upper end cover the upper edge of the inlet hold on the sleeve, the pump oil chamber will become a sealed oil chamber at the top of the plunger, the p lunger continues to move upward, the pressure in the pump oil chamber will rapidly increased, when the pump oil pressure > the spring force of the oil outlet valve + the residual pressure of the high pressure pipe, the oil outlet valve will be pushed open, the high pressure oil will enter the high pressure pipe through the oil outlet valve, and sprayed into the combustion chamber through the injector.



（3）working principle of injection pump ③oil return process The plunger supply oil upward, when the plunger moves to a position where the chute connected to the oil return hole on the sleeve, the low pressure oil channel of the pump oil chamber will be connected with the mid level outlet, radial hole and the chute, the oil pressure will be lowered, the oil outlet valve will rapidly closed under the spring force, and the oil supply will be stopped. Then the plunger will still move upward, when the cam convex

，

portion turned over the highest position the plunger will move downward under the spring force, and the next cycle is begin.


Section 4 Fuel supply system 3.governor （1））working principle The fuel injection volume can be changed by the governor by controlling the movement of the governor rake. When the engine load increased and the rotation speed decreased, the governor will automatically increase the amount of fuel injection to prevent engine power off. When the engine load decreased and the rotation speed increased, the governor will automatically reduce the amount of fuel injection to prevent the engine speed is too high. Right picture shows the basic structure

1－pull-rod；2－speed adjusting bolt；3－guide rod；4－floating lever；5－ high speed limit screw；6－control handle；7－idle screw； 8－shift yoke rod；9－idle spring；10－stroke adjusting screw； 11－speed adjusting sleeve；12－flyweight；13－roller；14－camshaft；15－ adjusting speed spring；16－adjusting gear；17－connecting rod；18－start spring；19－ speed adjusting rod；20-speed stabilizing spring

of the RAD type speed governor.


Section 4 Fuel supply system 4.Fuel delivery pump

（1）structure

The fuel delivery pump is installed on one side of the oil injection pump and is droven by the eccentric cam of the injection pump camshaft.

（2）function The function of the delivery pump is to send the fuel from the fuel tank to the low pressure oil chamber of the oil injection pump by passing through the oil filter. The fuel delievery pump is equipped with a manual pump, which is used to exclude the air in the low pressure oil channel, and ensure the channel full of diesel oil, so that the engine can easily be started. The screw in the air filter inlet channel is equipped with a strainer to filter the impurities in the fuel.


Section 4 Fuel supply system 4. Fuel delivery pump

（3）working principle The eccentric gear pushes the piston move downward through the push rod, volume of the working chamber under the pistion decreased, the inlet valve closed, the outlet valve opened, and the volumn of the pressure chamber above the piston increases, which causes the generation of a vacuum, and the diesel can flow into the pressure chamber along the direction of the arrow by passing through the outlet valve. Eccentric gear turns away, the piston moves upward under the force of the spring, negative pressure created in the working chamber beneath the piston, the outlet valve closed, and the inlet valve openned, oil flows into the working chamber, the volume of pressure chamber B decreased by the upward movement of the piston, the pressure of the diesel in the chamber increased, oil flowed to the outside, which pressure controlled by the spring pretightening

Working principle map of oil delivery pump force.


Section 4 Fuel supply system 4. Fuel delivery pump （3））working principle When the oil input of the fuel delivery pump is greater than the output, the pressure of the oil pipeline and the pressure chamber B will increased to be greater than or equal to the spring pretightening force. At this time, the piston can not return to the upper dead point, the piston stroke will be decreased, and the amount of the oil supply will also be increased accordingly, such as to achieve the automatic adjustment of the oil volume and oil pressure. Working principle map of oil delivery pump


Section 4 Fuel supply system 5.Oil injector （1））working principle The fuel outlet is closed by the injector nozzle needle under the pressure of the

Outlet valve

Injector unit

injector spring. When the injection pressure reaches the injector spray pressure, the needle will be jached up, and the fuel will be sprayed out in the form of mist. Rotating the regulating screw, the spring pressure will be changed, that is the adjustment of the fuel injection pressure.


Section 4 Fuel supply system 5.Oil injector （2））Function and requirement The function of the fuel injection pump

Overflow pipe unit Return oil tank Pressure adjusting valve

is to spray the high pressure fuel oil from the fuel injection pump, under a certain

Injector unit spring

pressure, in the form of mist. Vaporific injecting text

Requirement: ① Uniform atomization ② Rapid injection ③ No post-drop phenomenon ④ The shape and direction of the oil beam suit the form of the combustion chamber.

Push rod Connect oiloilinjector pump Injector unit body(nozzle)


Section 4 Fuel supply system 6.Fuel water-separator The fuel water-separator contains electric

Electric pump

pump, water filtration, electronic controllers and other three parts. Main function of the fuel water-separator 1

：

、To solve problems, such as engine start

Oil inlet M16X1.5

failure, engine power off and lack of motivation in cold regions caused by fuel wax. 2

、To solve the problem of high rate of starter

failure caused by the using of starter to discharge gas. 3

Electronic controller

、To solve users' complain about the artificial

air exhaust when doing filter maintanance, or when there were air in the pipe. 4

、To solve engine start failures caused by big

Oil outlet M16X1.5

temperature changes in some places, sharp temperature decrease and Cross-regional operation.

Water filter


Section 4 Fuel supply system 6.Fuel water-separator Working principle of electric pump 1

、Pump oil and discharge gas: Open the electric

pump by the electronic controller of the electric oil pump filter, a vacuum negative pressure is formed by the high-speed rotation of the inner roller, which will make the fuel oil flow in the 24V oil pumping heating power

low pressure oil pipe, so that the air will be discharged from the fuel pipe. 2

、Turn

t h e i gnition switch to the ON

position,the fuel water-separator will begin to pump oil, and will be automatically stopped in 10

input Negative earth

Union DJ431DJ431-4C 24VDC power

minutes, if need to pump oil again, turn off the ignition switch, restart it again, the new cycle will begin.

、When the environment temperature is below 7℃, and the ignition switch turned to the ON

30A fuse

3

position, the fuel water-separator begins to start

T15 switch

heating, and will be automatically stopped when the tempreture reaches 24

℃.


Section 4 Fuel supply system 7.Fuel filter Fuel filter is a two-stage series, the primary filter is felt filter, the fine filter is paper filter, both of them are mounted on the same filter seat, with a "←" mark casted on the surface to indicate the flow direction of the fuel oil. The function of the filter is to remove harmful particles and water from the engine fuel gas system to protect the pump nozzle, cylinder liner, piston rings, etc., reduce wear and avoid jam. Fuel oil filtered in the fuel water-seperator, then into the fuel filter to further filtration, and finally into the fuel supply pump of the high-pressure pump.


Section 4 Fuel supply system 5.Oil injector

（3）injector style Currently the fuel injectors adopted by the

Filter needle

Inlet port

diesel engine are all closed injector, which has two kinds, hole type and shaft needle type.

Outlet port adjusting washer

The injector of the Weichai WD10G220E23 engine is the closed hole type, the opening pressure is 225+5bar, the nozzle is thin-walled heat-resistant steel

Pressure adjusting spring

sleeve, with a insulation sheath in the nozzle head, the purpose of this design is to reduce

block

Injector body Spring seat

the direct contact between the nozzle and the gas, so as to reduce the temperature of the nozzle head, and improve the working

Needlevalve part

reliability and service life of the nozzle.

Tensioning cap


Section 5 Lubrication system

、Function

1

The function of lubrication system is to delivery certain amount of lubricating oil to the surface of the parts with relative motion, realizing the liquid friction, reducing the friction resistance and mechanical wear, and cleaning and cooling the surface of the parts. Summarized as follows:

：lubricating parts surface, reducing

Lubrication

wear and engine power consumption.

：Cleaning the friction surface, removing

Wash

abrasive dust and other foreign matters. cooling

：Engine oil can take away heat

generated by friction when cycles in the Lubricating system. sealing

：Forming a film of oil between parts to

1- pressure limiting valve;2-oil strainer;3-engine oil pump;4-radiator;

improve sealing, prevent leakage of gas and oil.

5- pressure limiting valve;6-crankshaft;7-connecting rod small end;

antirust

8-camshaft;9-rocker arm shaft;10-tappet;11-injector pump

：Forming a film of oil on the surface of

parts to prevent the corrosion and rust.

12-air compressor;13-supercharger;14-main oil passage; 15- pressure limiting valve;16-engine oil filter;17-filter by-pass valve


Section 5 Lubrication system 2、、lubrication method 1、、Pressure lubrication：：Using the oil pump to continuously send certain pressure of lubricating oil to the friction surface, which is called pressure lubrication, such as crankshaft bearings, connecting rod bearings and camshaft bearings, etc.

2 、 Splash lubrication ： T he wa y of using oil droplets or oil mist flied up by engine parts to lubricate friction surface is called the splash lubrication, such as cylinder wall, piston pin, valve cam tappet surface, etc.

3、、Composition lubrication：： Lubrication of two or more than two kinds.

1- pressure limiting valve;2-oil strainer;3-engine oil pump;4-radiator;

4、、Grease lubrication：：Such as

5- pressure limiting valve;6-crankshaft;7-connecting rod small end;

lubrication in water pump.

8-camshaft;9-rocker arm shaft;10-tappet;11-injector pump 12-air compressor;13-supercharger;14-main oil passage; 15- pressure limiting valve;16-engine oil filter;17-filter by-pass valve


Section 5 Lubrication system 3、、Main parts The lubrication system is mainly composed of oil strainer, oil pump, oil filter, main oil pressure limiting valve, oil radiator and oil pan and other components.

Engine oil pump Oil pan

Engine oil cooler Engine oil filter


Section 5 Lubrication system 3、、main spare part 1、、oil strainer Oil strainer installed in the oil pan for coarse filter, as shown in the right picture.

1-oil strainer 2-gasket 3-washer 4-bolt


Section 5 Lubrication system

、main spare part 2、engine pump

3

When the gear oil pump works, the driving gear drives the driven gear to rotate in counterclockwise direction, the engine oil fully filled between the alveolar will flow from the oil inlet chamber to the oil outlet chamber along the wall of the pump housing, on the side of the oil inlet chamber, because

Drive gear

Pump body

Pump cover

of the vaccum generated by the gear disengaging and the oil continuously being brought out, the oil in the oil pan will enter the oil inlet chamber through the oil strainer under the atmospheric pressure, but on the other side of the oil outlet chamber, because of the pressure effect generated by the gear engaging and oil continuously being brought in, the oil will be pumped out at a certain pressure.

Driving gear shaft

Drive n gear

Driving spring gear

Pressure limiting valve


Section 5 Lubrication system 3.Engine filter When the engine works, metal wear debris, dust in the air and carbon particles generated by incomplete combustion of the fuel oil will go into

spring

the engine oil, and the engine itself will generate

By-pass valve

gelatinous precipitates due to thermal oxidation, if such dirty oil were directly delivered to the surface

of

the

moving

part,

mechanical

impurities in the engine will become abrasive

lever

which will accelerate the parts wear and cause the oil duct obstruction, piston ring, engine valves and other components cementation.

Filter insert

Therefore, oil filter is designed in the lubricating system to filter the engine oil and extend the service life of the machine.

pressing spring

The oil flow direction shown by the arrows in the right picture, there is a bypass valve on the upper cover, when the filter insert is blocked, the bypass valve will be openned by the pressure of

Paper filter

the engine oil, the lubricating oil will flow directly into the main oil channel without passing through the valve insert, thus guarantees the engine oil supply could not be interrupted.


Section 5 Lubrication system 4.Enging cooler The engine oil cooler placed in the engine oil

Oil outlet port

cooling channel, using the coolant temperature to control the temperature of the lubricating oil, the lubricating oil could be cooled by the coolant

Water inlet port

insert

Water inlet port

when the its temperature is high, when the engine starts, heat will be absorbed from the coolant to

cover

quickly raise the temperature of lubricating oil.

insert

The Weichai WD10G220E23 uses the plate-fin radiator, which is installed in the coolant channel

Water outlet port

on the right side of the engine, with good cooling

by-pass valve Oil outlet port

capacity, and ensure the engine oil works in a suitable temperature range.

Engine cooler

The engine oil cooler has a safety valve, with an opening pressure of 0.6Mpa to ensure the engine is lubricated as usual, the pressure can prevent the safety valve openned and the engine oil flow directly into the main channel without by passing

Oil outlet port Oil inlet port

through the oil cooler when the engine oil cooler blocked.


Section 5 Lubrication system 5.Crankshaft case ventilation When the engine works, part of the combustible gas mixture and the exhaust gas leaks into he crankcase through the

Air filter

piston rings, which will be condensed into droplets to dilute the lubricating oil. Meanwhile, high temperature of the exhaust gas and the acidic substances or water vapor in the exhaust gas will erode parts, and make the oil performance deterioration. In addition, since the mixture gas and the exhaust gas enters the crankcase, the pressure in the

Air inlet pipe

crankcase will be inceased, temperature will be raised, and engine oil will easily leak outward from the oil seals, gaskets,

Natural ventilation

etc.


Section 5 Lubrication system 5.Crankshaft case ventilation T h e c r a n k c a s e o f t h e We i c h a i WD10G220E23 engine uses natural ventilation, the crankcase is connected to the air through oil and gas separator. The function of the oil and gas separator is to ensure crankcase pressure and environmental pressure balanced, and separate the high temperature oil in the crankcase, the separated liquid engine oil will flow back to the oil pan, which will reduce oil consumption.


Section 5 Lubrication system 3.Engine oil filter The Weichai WD10G220E23 engine oil filter is a rotary type paper filter, good filtering effect, strong filtering pass-ability, and an opening pressure of 250 ± 17.5kPa bypass valve to prevent the pressure limiting valve openned when the filter blocked. The engine oil filter should be changed according to the using condition and maintenance requirements, can not be washed and reused. 1-assembly seat 2-washer 3、4-bolt 5-engine oil filter


Section 6 Cooling system Cooling water line 1、、Cooling system function The function of the cooling system is to timely distribute heat absorbed by the heated parts to ensure the engine

Radiator cap Radiator

Water temperature indication

working in the most suitable temperature Water temperature sensor

conditions. Shutter

According to the cooling mode, It can be divided into two types, the air-cooled, water-cooled. The Weichai WD10G220E23 engine

Water pump

Divide water pipe

Fan

using the forced closed pressure circulating water cooling. It consists of the radiator, water

Drain plug

pump,fan, cooling water jacket and a thermostat device.


Section 6 Cooling system 3、、main spare part of cooling system 1、、radiator Radiator is also called water tank, which is composed of upper water chamber, radiator core and the lower water chamber, etc. Its main function is to increase the heat dissipation area, accelerate the water cooling. The coolant temperature can be reduced by 10-15 ℃ after passing through the radiator, a fan installed behind the radiator to take away the heat released from the radiator by coordination with the radiator.


Section 6 Cooling system 2

、Water pump

The coolant is pumped into the right side water chamber of the engine by the water pump, first cool the oil cooler, then entering the water channel inside the engine to cool the cylinder,

Pump shaft

next entering the cylinder head water chamber through the string holes on the cylinder block and

Pump impeller

cylinder head to cool the gas valve, injector and cylinder head, finally flow back to the water outlet pipe which end connect with the

Water outlet pipe

thermostat.

Water inlet pipe


Section 6 Cooling system

Thermostat in the small circulation

Thermostat in the large circulation

3.Thermostat The engine thermostat contains a thermal element( wax which could expand when heated and contract when cooled ) which can be moved up and down according to the different remperature. When the coolant temperature is low, the wax will contract, which will close the mouth of the channel leading to the radiator, and open the channel leading to the water

to radiator

to radiator Thermostat

Spring

Thermostat

Spring

valve

valve

Plunger

Plunger

Open the entrance to radiator

pump(small circulation). When the coolant temperature rises to a certain extent, the was will expand, which will open the mouth of the channel leading to the radiator, and close the channel leading to the water pump(large circulation).

From engine

Hot sensing body

From engine

Hot sensing body

Open the entrance to pump To pump

Cooling water in low temperature

Cooling water in high temperature To pump


Section 6 Cooling system 3.Thermostat Thermostat of the Weichai WD10G220E23 engine, as shown in the right picture.

Valve seat

Small spring

Valve Vice valve Support


Large spring


Shell

Section 6 Cooling system 4.Cooling water circulation The cooling water cycle is divided into small circulation and circulation which are two kinds of circulation state of the coolant circulation. When the temperature is below 71

℃, the

cooling ability will be weak, which will lead the coolant temperature rise rapidly, so as to ensure all parts of the engine rapidly hot or avoid the engine to be too cold, at this time, the circuit is short, and the flow is small, which is called samll circulation, the flow path: thermostat - pumps - water - oil radiator thermostat. When the temperature is higher than 82

℃, the

cooling ability will be strong, which will lead the coolant temperature decrease so as not to get too high, at this time, the cooling circuit is long, and flow is large, so called large circulation.The path: thermostat - water pump-engine oil radiatorwater sleeve-thermostate. When the temperature is between 71-82

℃, the

Large spring

cycle enter mixed circulation, namely, the small circulation and large circulation are carried on at the same time.


Section 7 Air intake and exhaust system 1

、Function

1

2

3

4

5

6

The intake and exhaust system draws air into

Valve seat

the cylinder, mix and burn it with the fuel oil, and then discharg the exhaust gas to the outside. The fresh air enters the turbocharger inlet after passing through the air cleaner, the pressure and air density will be incr eased,

and the

temperature will rised. The fresh air enters the turbocharger inlet after passing through the air cleaner, the pressure will be increased, and the air density and temperature will be increased accordingly. The cooled air will be burned in the cylinder after passing through the valve, changed into exhaust gas and discharged outside the cylinder through the compression stroke. The exhaust air will enter the turbocharger through the exhaust pipe, and will be discharged outside from the outlet of the turbocharger after pushing the

1-air filter

2-intercooler

3-piston

4-turbocharger

turbine rotate at high speed. Exhaust gas from the turbocharger will be discharged into the atmosphere after passing

5-air line connecting pipe

6-silencer

through the silencer and carbon removal.


Section 7 Air intake and exhaust system 3

、Spare part

1.Air filter Function

：The cleaned air will enter the

combustion chamber after filtered from dust and impurities to reduce the wear between the piston and cylinder liner, the piston group and valve group. Principle

：After entering the air cleaner, the air

will rotate between the air cleaner housing and air filter insert under the action of the shroud, larger particles and dust in the air will be thrown to the air cleaner housing due to the centrifugal force, and will fall along the housing into the bottom cover and dust collecting bag, the centrifuged and purified air will pass through the paper filter and the felt security filter to filter out fine dust, and at last enter the turbocharger inlet pipe through the central channel of the safety filter. If the filter is dirty, when the engine works, the degree of the vacuum will be increased, and the indicator of the filter will turn red to warn that the air cleaner needs to be cleaned or replaced.


Section 7 Air intake and exhaust system 3、、Spare part 2.Turbocharger ①Principle ：Using the engine exhaust pressure waves to drive the turbine,

Engine Air outlet line Turbocharger

bring the compressor impeller on the other side to blow air.

②Function: Supply additional air to the

Air inlet port

engine, so that it can burn more fuel, and generate more power.

Air outlet line


Section 7 Air intake and exhaust system 3、、Spare part 2.Turbocharger ③Structure：： The turbocharger is mainly composed two parts , the compressor and t h e turbine. The compressor in mainly includes single stage centrifugal compressor, diffuser and the compressor casing. The turbine section: including turbine shell, single-stage radial turbine.


Section 7 Air intake and exhaust system 3、、Spare part

Air outlet

2.Turbocharger

outlet connection Rear cover

Air compressor casing, impeller casing and the middle connection are the main fasteners, the impeller casing and the middle connection connected with each other by bolts and cover plate, the

Air compressor casing

compressor casing and the middle connector connected with each other by the rear plate of the

, bolts and cover

Inlet connection

plate. Air compressor casing could be installed in different directions around the axle.

Air inlet Air compressor impeller


Section 7 Air intake and exhaust system 3、、Spare part 2.Turbocharger

Double flowing way

Heat shield

Turbocharger rotor bearing is the inner supporting type, with floating bearing

Air outlet

locating in the middle connector between the two impeller, axle force of the rotor depends on the end surface of the thrust bearing to support.

Thrust bearing and seat Floating bearing

Exhaust flange

Turbine and shaft Connection flange

Air inlet RELIABILITY IN ACTION 86

Section 7 Air intake and exhaust system 3、、Spare part 2.Turbocharger Turbine shaft and turbine are welded together as a whole part, impeller is installed on the turbine shaft with clearance coordinate, and be compressed by nut. Rotor working rotation speed is from tens of thousand to more than two hundred rotation per minute. Purpose of the moving balance •

lengthen the bearing life.

•

reduce vibration

•

reduce noise

•

reduce power lose

•

reduce rotor load

转子Rotor


Section 7 Air intake and exhaust system 3、、Spare part 2.Turbocharger ④ Lubrication of the turbocharger

Oil inlet

The turbocharger adopts pressure lubricaiton, the lubricating oil flows into the oil inlet through the main oil channel on the fuselage, enter the lubrication system, and then return back to the oil pan through the oil outlet. Function of the lubrication system. • Cool heat generated from the turbocharger working. • Supply lubricating oil to the bearing system. • Provide film support for the rotor moving balance.

Oil outlet


Section 7 Air intake and exhaust system 3、、Spare part 3.Intercooler Function: Cool the heated air from the turbocharger, increase the air density, improve engine gas charging efficiency. Generally speaking, the temperature of the air will be increased more than 1 0 0 ℃ a ft er p as s i n g t h rou gh t h e turbocharger, the air will expand after being heated, which is not good for the air inlet, but the temperature could be reduced by passing through the charge air cooler. • Classification: air-air charge air cooler, water-air charge air cooler. Notice: LG956L engine doesn't have a charge air cooler.


Section 7 Air intake and exhaust system 3、、Spare part 4.Silencer Change the flow direction of the exhaust air to consume the energy of the exhaust air by ways of , and balance air flow pressure fluctuation to get the needed attenuation character, so as to reduce the noise.


Section 8. Common malfunction 1. Engine does not start

91

Serial number 1

Cause of malfunction

Repairing method

Starter motor speed is too low

Check the starting system, cranking speed shall not be less than 110 r/min.

2

Air in fuel supply system

1. Check fuel pipe connector for loose. Release bleed screw on the fuel filter, and use hand pump to pump fuel, until the overflow of fuel without air bubbles. 2.Release high pressure fuel pipe connection on injector, and use hand pump to pump fuel, until the overflow of fuel without air bubbles.

3

Fuel line blocked

Check fuel supply lines for unobstructed.

4

Fuel filter blocked

Replace the spin-on filter element of fuel filter assembly.

5

The delivery pump can not feed Check the fuel inlet lines for leaks and fuel delivery pump for fuel or feed intermittently malfunction.

6

Fuel injection less, no injection or injection pressure low

1. Check the injector spray condition; 2. whether the injection pump plunger and the outlet valve is worn or stuck, whether the plunger spring and outlet valve spring is broken.

7

Starting system circuit wiring error or poor contact

Check the wiring is correct and reliable.

8

The battery power insufficient

Charge the battery.

9

Starter motor carbon brushes and commutator contact poor

Repair or replace the electric brush; clean the commutator surface by abrasive paper and blow it clean.

10

Low compression pressure low due to piston ring excessive wear or valve leaks

Check valve clearance, valve spring, valve guides and sealing of valve seat, it is necessary to grinding valve seats if the sealing is poor.

11

Fuel shut-off solenoid connector may be loose or dirty, Tighten, clean or replace. corroded

12

Fuel injection timing is not assembled correctly

Check and adjust.

Section 8. Common malfunction 2. Engine lacks of power

Serial number

Repairing method

1

Air intake blocked

Check the air filter and air intake, clean or replace the air filter element.

2

Exhaust back pressure is too high

Check valve timing, adjust if necessary; clean exhaust pipes.

3

Fuel lines leaking or blocked

Check sealing conditions of fuel lines and fittings,check fuel filter for blocked, replace spinon filter element, check injection pump sealing.

4

Fuel injection pump plunger excessive wear

Check and replace the plunger and barrel assembly.

5

Fuel injector poor atomization

Check fuel injection pressure,clean up the carbon deposit, adjust and repair.

6

Fuel injection advance angle is Check and adjust. smaller or larger than normal

7

The air phase is error

8

Cylinder head gasket air leaks

9

Valve sealing poor Piston rings is worn excessively

10

92


Check and adjust valve timing and valve clearance. Tighten the cylinder head bolts in sequence in accordance with specified torque or replace cylinder head gasket. Grind or replace to regrind. Replace piston rings.

Section 8. Common malfunction 3. Exhaust black smoke

Serial number

93


Repairing method

1

Air intake blocked

Check the air filter and air intake pipes and clean-up.

2

Poor fuel quality

Use fuel up to specification

3

Fuel injector poor atomization Check, repair, or replace.

4

Valve clearance is excessive

Adjust valve clearance in accordance with the standard

Section 8. Common malfunction 4. Exhaust white smoke, blue smoke

Serial number 1 2 3 4

94

Cause of malfunction Poor fuel quality, with excessive water in fuel Compression pressure is low, incomplete combustion Air supply or fuel feed timing is not correct Compression pressure is low, incomplete combustion

Repairing method Replace fuel up to specification. Check piston ring and cylinder head gasket and replace it. The specialized staff to check and adjust. Check piston ring and cylinder head gasket and replace it.

Section 8. Common malfunction 5. Oil pressure is too low

Serial number 1 2 3 4 5 6

95

Cause of malfunction Oil thin, or use improper oil The oil pump rotor is worn or assembly clearance is too large Oil filter pressure regulator valve failure The pump inlet pipe cracks The pump inlet pipe mounting bolts loose Shaft bearing clearance is too large

Repairing method Select appropriate oil according to specification Replace the pump Repair Repair, replace tighten to specified torque Check and replace

Section 8. Common malfunction 6. Oil pressure is too high

Serial number

96


Repairing method

1

Temperature is too low, the oil viscosity is large

Choose specified type of oil, it is required to run at slow speed after start, check wheel the oil temperature is normal

2

Pressure relief valve blocked

Check, clean

Section 8. Common malfunction 7. Excessive oil consumption

Serial number 1 2 3 4

97

Cause of malfunction External oil line leaks Diesel engine is overload The type of oil is improperly The piston is stuck or excessively worn

5

Cylinder bore is worn excessively

6

Valve guide is worn, valve stem sealing failure

Repairing method Check and repair Reduce the load Use as required Check, repair, and replace if necessary Cylinder boring for increased piston or installing the repair-using cylinder liner Check and replace

Section 8. Common malfunction 8. High coolant temperature

Serial number 1 2 3 4 5 6

98

Cause of malfunction Insufficient cooling water, the water flow is too small Whether the belt is too loose Water pump leakage Thermostat is failure or damaged Water temperature sensor is damaged, the water temperature sensor failure The cylinder head gasket is blow-out

Repairing method Check whether the cooling water is sufficient and add if necessary Adjust Repair in time Check and replace Check whether the actual temperature is identical to the gauge indicating value; if not, replace the temperature sensor or the temperature gauge Check and replace

THE END


01 Engine System LG956L

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