C9 Marine Marine Engine X9Y00001-UP X9Y00001-UP(SEBP4 (SEBP4250 250 - 8! - "o#$%en&a#i' "o#$%en&a#i'n n
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Bienvenido: r080es10 Producto: MARINE ENGINE Modelo: C9 MARINE ENGINE X9Y Configuración: C9 Marine Engine X9Y00001-P
Operación de Sistemas C9 Marine and C9 Marine Generator Set Engines Número de medio -SENR9663-10
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Fuel System SMCS - 1250
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(1) Unit injector hydraulic pump (2) Oil flo to engine (3) Oil filter (4) !ngine oil pump (") Injectors (#) Oil cooler (7) $igh pressure oil passage (%) &uel supply passage (') &uel transfer pump (10) &uel filter (11) rimary fuel filterater separator (12) &uel tan* (13) &uel pressure regulator (14) +ac* of camshaft gear (1") ,peedtiming sensors (1#) !lectronic -ontrol .odule (!-.) (17) Oil temperature sensor (If !/uipped) (1%) +oost pressure sensor (1') !ngine coolant temperature sensor (20) Inlet air temperature sensor (21) tmospheric air pressure sensor (If !/uipped) (22) !ngine oil pressure sensor (23) &uel pressure sensor (24) hrottle position sensor
Introduction he operation of the fuel system of the $ydraulic !lectronic Unit Injector ($!UI) is completely different from any other type of fuel system s ystem that is actuated mechanically he $! UI fuel system is completely free of adjustment djustments to the components that are mechanical can not e made -hanges in performance are made y installing different softare in !-. (1#) his fuel system consists of four asic components 5 $!UI $!UI (") (") 5 !-. !-. (1# (1#))
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• Unit injector hydraulic pump (1) • Fuel transfer pump (9) Note: The components of the HEUI fuel system are not serviceale! These fuel system components must not e disassemled! "isassemly #ill dama$e the components! If the components have een disassemled% &aterpillar may not allo# a #arranty claim or &aterpillar may reduce the #arranty claim!
Component Description Hydraulic Electronic Unit Injector
Illustration '
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(,) Unit injector
The HEUI fuel system utili-es a hydraulically actuated electronically controlled unit injector (,) ! .ll fuel systems for diesel en$ines use a plun$er and arrel in order to pump fuel under hi$h pressure into the comustion chamer! This fuel is pumped into the comustion chamer in precise amounts in order to control en$ine performance! The HEUI uses en$ine oil under hi$h pressure in order to po#er the plun$er! .ll other fuel systems use a fuel injection pump camshaft loe in order to po#er the plun$er! /ecause the HEUI is much different% a technician must use different trouleshootin$ methods! The HEUI uses en$ine lurication oil that is pressuri-ed from * 0a (23 psi) to ', 0a (*, psi) in order to pump fuel from the injector! The HEUI operates in the same #ay as a hydraulic cylinder in order to multiply the force of the hi$h pressure oil! /y multiplyin$ the force of the hi$h pressure oil% the HEUI can produce injection pressures that are very hi$h! This multiplication of pressure is achieved y applyin$ the force of the hi$h pressure oil to a piston! The piston is lar$er than the plun$er y appro4imately si4 times! The piston that is po#ered y en$ine lurication oil under hi$h pressure pushes on the plun$er! This en$ine lurication oil under hi$h pressure is called the actuation pressure of the oil! The actuation pressure of the oil
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generates the injection pressure that i s delivered by the unit injector. Injection pressure is greater than actuation pressure of the oil by approximately six times. Low actuation pressure of the oil results in low injection pressure of the fuel. During conditions of low speed such as idle and start, low injection pressure is utilized. High actuation pressure of the oil results in high injection pressure of the fuel. During conditions of high speed such as pea tor!ue and acceleration, high injection pressure is utilized. "here are many other operating conditions when the injection pressure is between the minimum and the maximum. #egardless of the speed of the engine, the H$%I fuel system provides infinite control of injection pressure.
ECM $&' ()*+ is located on the left side of the engine. "he $&' is a powerful computer that provides total electronic control of engine performance. "he $&' uses data from engine performance that is gathered by several sensors. "he $&' uses this data in order to mae adjustments to the fuel delivery, injection pressure and injection timing. "he $&' contains programmed performance maps (software+ in order to define horsepower, tor!ue curves and rpm. "his software is commonly called the personality module. "he $&' does not have a replaceable personality module. "he personality module is a permanent part of the $&'. "he personality module can be reprogrammed by using &aterpillar $lectronic "echnician ($"+. $&' ()*+ logs faults of engine performance. "he $&' is also capable of running several diagnostic tests automatically when the $&' and &at $" are used together.
Unit Injector Hydraulic Pump
Illustration ()+ %nit injector hydraulic pump
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%nit injector hydraulic pump ()+ (high pressure oil pump+ is located at the left front corner of the engine. "he unit injector hydraulic pump is a variable delivery piston pump. "he unit injector hydraulic pump uses a portion of the engine lubrication oil. "he unit injector hydraulic pump pressurizes the engine lubrication oil to the injection actuation pressure that is re!uired in order to power the H$%I injectors (/+ .
Pump Pressure Regulator "he pump pressure regulator is internal to the unit injector hydraulic pump. "he pump pressure regulator is a valve of high precision that controls pump outlet pressure (actuation pressure+ by changing pump outlet flow. "he performance maps of $&' ()*+ contain a desired actuation pressure for every engine operating condition. "he $&' sends a control current to the pump pressure regulator. "he control current should mae the actual actuation pressure e!ual to the desired actuation pressure. "he pump pressure regulator is an ac tuator that converts an electrical signal from the $&' to the mechanical control of plunger sleeves in order to change the pump outlet flow and the pump outlet pressure.
Fuel Transfer Pump
Illustration 2 ()+ %nit injector hydraulic pump (+ Auel transfer pump
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Fuel transfer pump (9) is mounted on the back of unit injector hydraulic pump (1). The fuel transfer pump is used in order to draw fuel from fuel tank (12). Also the fuel transfer pump is used in order to pressuri!e the fuel to "#$ k%a (&# psi). The pressuri!ed fuel is supplied to injectors (#) . The fuel transfer pump is a 'ear pump. The pump is mounted on the back of the unit injector hydraulic pump. The fuel transfer pump is drien by the hydraulic pump shaft. A relief ale in the fuel transfer pump limits the outlet pressure to &9 * &9 k%a (1$$ * 1$ psi). Fuel is drawn from the tank to the inlet port of the pump. The rotation of the 'ears causes the fuel to flow out of the pump outlet port throu'h the secondary fuel filter (1$) and to the fuel supply passa'e () that is located in the cylinder head.
Injection Actuation Pressure Sensor (IAP) The +A% ,ensor monitors injection actuation pressure. The +A% ,ensor sends a continuous olta'e si'nal back to -/ (1&). The -/ interprets the si'nal. The -/ is aware of the injection actuation pressure at all times.
HEUI Fuel System Low Pressure Fuel System
+llustration #
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(1) Unit injector hydraulic pump (5) Injectors (8) Fuel supply passage (9) Fuel transfer pump (10) Fuel filter (11) Primary fuel filter!ater separator (1") Fuel tan# (1$) Fuel pressure regulator
%he lo! pressure fuel system ser&es t!o functions' %he lo! pressure fuel system supplies fuel for comustion to injectors (5)' %he lo! pressure fuel system also supplies ecess fuel flo! in order to remo&e air from the system' %he lo! pressure fuel system consists of fi&e asic components* + Fuel tan# (1") + Primary fuel filter!ater separator (11) + %!o micron secondary fuel filter (10) + Fuel transfer pump (9) + Fuel pressure regulator (1$) Fuel transfer pump (9) is mounted on the ac# of unit injector hydraulic pump (1) ' Fuel is dra!n from fuel tan# (1") and flo!s through a thirteen micron primary fuel filter!ater separator (11)' %he primary fuel filter!ater separator remo&es large deris f rom the fuel' %he deris may ha&e entered the fuel tan# during fueling' %he deris may ha&e also entered the fuel tan# through the &ent for the fuel tan#' %he primary filter element also separates !ater from the fuel' %he !ater is collected in the o!l at the ottom of the primary fuel filter!ater separator' Fuel flo!s from the primary fuel filter!ater separator to the inlet side of fuel transfer pump' ,n inlet chec# &al&e in the inlet port of the fuel transfer pump opens in order to allo! the flo! of fuel into the pump' ,fter the fuel flo! has stopped- the inlet chec# &al&e closes in order to pre&ent fuel flo! out of the inlet port' Fuel flo!s from the inlet port in the pump to the outlet port' Pressuri.ed fuel flo!s from the outlet port of the pump to the t!o micron secondary fuel filter (10)' , t!o micron secondary fuel filter is standard on all /aterpillar engines' %hese fuel filters are high efficiency' %his filter remo&es &ery small arasi&e contaminants from the fuel' %he primary fuel filter!ater separator !ill not trap these small contaminants' ery small arasi&e particles in the fuel cause arasi&e deterioration of the unit injectors' %he t!o micron secondary fuel filter remo&es 98 percent of all particles that are t!o microns and those particles that are larger than t!o microns' %he use and regular maintenance of this t!o micron filter !ill pro&ide a significant impro&ement in injector life' Fuel flo!s from the t!o micron secondary filter to the fuel supply passage (8) in the cylinder head' %he fuel supply passage is a drilled hole !hich egins at the front of the cylinder head' %he fuel supply passage etends to the ac# of the cylinder head' %his passage connects !it h each unit injector ore in order to supply fuel to unit injectors' Fuel from the transfer pump flo!s through the cylinder head to all of the unit
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injectors. Excess fuel flows out of the back of the cylinder head. After the excess flows out of the back of the cylinder head, the fuel flows into fuel pressure regulator (13) . he fuel pressure regulator consists of an orifice and a check !al!e that is spring loaded. he orifice is a flow restriction that pressuri"es the supply fuel. he check !al!e that is spring loaded opens at 3# k$a (# psi) in order to allow the fuel which has flowed through the orifice to return to the fuel tank. %hen the e ngine is off and no fuel pressure is present, the check !al!e that is spring loaded closes. he check !al!e that is spring loaded closes in order to pre!ent the fuel in the cylinder head fro& draining back to the fuel tank.
Injection Actuation System Actuation Oil Flow
'llustration (1) nit injector hydraulic pu&p (3) -il filter (*) Engine oil pu&p (#) 'njectors
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(6) Oil cooler
The injection actuation system serves two functions. The injection actuation system supplies high pressure oil in order to power HEU injectors (!). "lso# the injection actuation system controls the injection pressure that is produced $y the unit injectors $y changing the actuation pressure of the oil. The injection actuation system consists of four $asic components% & Engine oil pump (') & Engine oil filter () & Unit injector hydraulic pump () & "* sensor Oil from engine oil pump (') supplies the needs of the engine lu$rication system. "lso# oil from the engine oil pump supplies the needs of unit injector hydraulic pump () for the fuel system. The capacity of the engine oil pump has $een increased in order to meet the additional flow re+uirement that is necessary. Oil that is drawn from the sump is pressuri,ed to the lu$rication system oil pressure $y the engine oil pump. Oil flows from the engine oil pump through engine oil cooler (6)# through engine oil filter ()# and then to the main oil gallery. " separate circuit from the main oil gallery directs a portion of the lu$rication oil in order to supply unit injector hydraulic pump (). " steel tu$e on the left side of the engine connects the main oil gallery with the inlet port of the unit injector hydraulic pump. The connection point is the top port of the manifold on the engine side cover. Oil flows into the inlet port of the unit injector hydraulic pump and the oil fills the pump reservoir. The pump reservoir provides oil to the unit injector hydraulic pump during start-up. "lso# the pump reservoir provides oil to the unit injector hydraulic pump until the engine oil pump can increase pressure. The pump reservoir also provides maeup oil to the high pressure oil passage (/) in the cylinder head. 0hen the engine is off and the engine cools down# the oil shrins. " chec valve in the pump allows oil to $e drawn from the pump reservoir in order to eep the high pressure oil passage full. Oil from the pump reservoir is pressuri,ed in unit injector hydraulic pump () and the oil is pushed out of the outlet port of the pump under high pressure. Oil then flows from the outlet port of the unit injector hydraulic pump to the high pressure oil passage in the cylinder head. The high pressure oil passage connects with each unit injector $ore in order to supply high pressure actuation oil to unit injectors (!). "ctuation oil that is under high pressure flows from the unit injector hydraulic pump through the cylinder head to all of the injectors. Oil is contained in the high pressure oil passage until the oil is used $y the unit injectors. Oil that has $een e1hausted $y the unit injectors is e1pelled under the valve covers. This oil returns to the crancase through oil drain holes in the cylinder head. Actuation Oil Pressure Control
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llustration / (4!) "rmature (46) *ressure regulator solenoid (4/) *oppet valve (4<) *ressure relief valve (43) "ctuator piston (9) *ump outlet port () :liding sleeve (4) :pill port () =rive gear (') Eccentric drive plate (!) dler (6) *lunger (/) 5hec valve
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The unit injector hydraulic pump is a variable delivery piston pump. The pump is designed in order to generate adequate flow under the conditions that are the most demanding. The unit injector hydraulic pump is driven by the gear train on the front of the engine. A drive gear (33) on the front of the pump turns the pump drive shaft. An eccentric drive plate (34) on the pump drive shaft causes the pump plungers (3) to move in and out within the pump barrel. As the plungers move out of the barrel! oil is drawn into the inside of the plunger through inlet ports in the eccentric drive plate. "il is forced out of the plunger when the plunger is pushed bac# into the barrel. This oil flow can flow through a spill port (3$) in the plunger or through an outlet chec# valve (3%) into the pump outlet port (3&) . 'ach plunger contains a spill port which is covered by a sliding sleeve (3) during part of the plunger stro#e. hanging the position of the sleeve changes the effective pumping stro#e of the plunger and increases or decreases pump outlet flow. The pressure of the injection actuation system is controlled by matching pump outlet flow to the flow demand for the injection actuation system. The position of the plunger sleeves is changed in order to control the pump outlet flow. *oving the sleeves to the left covers the plunger spill port for a longer distance. This increases effective pumping stro#e and pump outlet flow. *oving the sleeves to the right covers the plunger spill port for a shorter distance which reduces the effective pumping stro#e. This also reduces the pump outlet flow. All of the plunger sleeves are connected to an idler (3+). The idler is connected to an actuator piston ($,). *oving the actuator piston right or left causes the idler and sleeves to move the same distance to the right or to the left. Three forces act on the actuator piston. These forces determine the piston position. - pring force - /ump outlet pressure - ontrol pressure A combination of spring force and control pressure oppose pump outlet pressure. This combination determines the position of the actuator piston. /ump outlet pressure acts on the left side of the actuator piston. This moves the actuator piston to the right and decreases pump flow. ontrol outlet pressure acts on the right side of the actuator piston. This moves the actuator piston to the left and increases pump flow. pring force also acts on the actuator piston. This moves the actuator piston to the left and increases pump outlet flow. ontrol pressure is determined by the amount of current from the '* to the solenoid for the pump pressure regulator ($). A small amount of pump outlet flow goes through a small passage in the actuator piston. This small amount goes out of an orifice and into the control pressure cavity. The pressure in this cavity is limited by a small poppet valve. The opening of the poppet valve allows a portion of the oil in the cavity to flow to drain. A force holds the poppet valve closed. This force on the poppet valve is created by a magnetic field that acts on an armature ($+). The strength of the magnetic field determines the required pressure in order to overcome the force of the magnetic field. This pressure opens the poppet valve. An increase of current to the solenoid causes an increase to the following items0
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• The strength of the magnetic field • The force on the armature and poppet valve • The control pressure which opens the poppet valve A reduction of current to the solenoid causes a reduction to the following items: • The strength of the magnetic field • The force on the armature and poppet valve • The control pressure which opens the poppet valve An increase of current to the solenoid causes an increase in control pressure. A decrease of current to the solenoid causes a decrease in control pressure. An increase of current to the solenoid causes an increase in pump outlet pressure. A decrease of current to the solenoid causes a decrease in pump outlet pressure. The ECM monitors actuation pressure. The ECM constantly changes current to the pump pressure regulator in order to control actuation pressure. Three c omponents work together in a closed loop circuit in order to control actuation pressure. • ECM • IA sensor • ump pressure regulator The closed loop circuit works in the following manner: • The ECM determines a desired actuation pressure !y gathering information from sensor inputs and software maps. • The ECM monitors actual actuation pressure through a constant signal voltage from the IA sensor. • The ECM constantly changes control current to the pump pressure regulator. This changes the pump outlet pressure. There are two types of actuation pressure: • "esired actuation pressure • Actual actuation pressure "esired actuation pressure is the in#ection actuation pressure that is re$uired !y the system for optimum engine performance. The desired actuation pressure is esta!lished !y the performance maps in the ECM. The ECM selects the desired actuation pressure. The selection is !ased on the signal inputs from many sensors. The ECM is getting signal inputs from some of the following sensors: throttle position sensor% !oost pressure sensor% speed&timing sensors and coolant temperature sensor. The desired actuation pressure is constantly changing. The change is !ased on various signal inputs. The changing engine speed and engine load a lso cause the desired actuation pressure t o change. The desired actuation pressure is only constant under steady state conditions 'steady engine speed and load(. Actual actuation pressure is the actual system pressure of the actuation oil that is powering the in#ectors. The ECM and the pump pressure regulator are constantly changing the amount of pump outlet flow. This constant changing makes the actual actuation pressure e$ual to the desired actuation pressure.
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Pump Pressure Regulator Valve Operation The pump pressure regulator valve has the following three stages: • Valve operation (engine off) • Valve operation (cranking the engine) • Valve operation (running engine) Valve Operation (ENGINE OFF)
Illustration 8 (") #ctuator piston ($8) #ctuator spring ($1) %li&ing sleeve
'hen the engine is off there is no pump outlet pressure from the pump an& there is no current to the pressure regulator solenoi& from the *+, The actuator spring ($8) pushes the actuator piston (")
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completely to the left. The idler which is not shown and sliding sleeves (31) are moved to the left also. At this point, the pump is in the position of maximum output. Valve Operation (ENGINE CRANKING)
Illustration
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($%) &ressure regulator solenoid (3) 'rain ($") &oppet valve ($) Actuator piston (3) Actuator spring
'uring engine startup, approximately % *&a ("! psi) of in+ection actuation pressure is reuired in order to activate the unit in+ector. This low in+ection actuation pressure generates a low fuel in+ection pressure of a-out 3# *&a (#!!! psi). This low fuel in+ection pressure aids cold starting. In order to start the engine uicly, the in+ection actuation pressure must rise uicly. /ecause the unit in+ector hydraulic pump is -eing turned at engine craning speed, pump flow is very low. The 0* sends a
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strong current to the pressure regulator solenoid (26) in order to keep the poppet valve (27) closed. With the poppet valve in the closed position, all of the flow to drain (39) is blocked. he control pressure is e!ual to the pu"p outlet pressure. he h#draulic forces that act on each side of the actuator piston (29) are e!ual. he actuator spring (3$) holds the actuator to the left. he pu"p produces "a%i"u" flow until the 6 &'a ($7 psi) desired pressure is reached. ow, the *+& reduces the current to the pressure regulator solenoid in order to reduce control pressure. he reduced control pressure allows the actuator piston to "ove to the right. his reduces pu"p outlet flow in order to "aintain the 6 &'a ($7 psi) desired pressure. Note: f the engine is alread# war", the pressure that is re!uired to start the engine "a# be higher than 6 &'a ($7 psi). he values for the desired actuation pressures are s tored in the perfor"ance "aps of the *+&. he values for desired actuation pressures var# with engine te"perature.
-nce the unit inectors begin to operate, the *+& controls the current t o the pressure regulator. he *+& and the pressure regulator solenoid will "aintain the actuation pressure at 6 &'a ($7 psi) until the engine starts. he *+& "onitors the actual actuation pressure through the /' 0ensor that is located in the high pressure oil "anifold. he *+& establishes desired actuation pressure b# "onitoring several electrical input signals and the *+& sends a predeter"ined current to the pressure regulator solenoid. he *+& also co"pares the desired actuation pressure to t he actual actuation pressure in the high pressure oil passage. he *+& adusts the current levels to the pressure regulator solenoid in order to "ake the actual actuation pressure e!ual to the desired actuation pressure. Valve Operation (ENGINE RUNNING)
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Illustration 10
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(26) Pressure regulator solenoid
Once the engine starts, the EC controls the current to the !u"! !ressure regulator (26) in order to "aintain the desired actuation !ressure# $he I%P &ensor "onitors the actual actuation !ressure in the high !ressure oil !assage in the c'linder head# $he EC co"!ares the actual actuation !ressure to the desired actuation !ressure 67 ti"es !er second# $he EC adusts the current leels to the !u"! !ressure regulator *hen the actual actuation !ressure and the desired actuation !ressure do not "atch# $hese adust"ents "a+e the actual inection actuation !ressure eual to the desired inection actuation !ressure# Oil Flow (ENGINE RUNNING)
% s"all a"ount o- !u"! outlet -lo* -lo*s through the actuator !iston and into the control !ressure cait'# Control !ressure increases and the increased !ressure unseats the !o!!et ale# $he o!en !o!!et ale allo*s -lo* to the drain# $he EC changes control !ressure .' increasing or reducing the current to the !ressure regulator solenoid and resultant -orce on the !o!!et# $he -ollo*ing ite"s create a closed loo! s'ste"# / EC / I%P / Pressure egulator $his closed loo! s'ste" !roides in-initel' aria.le control o- !u"! outlet !ressure# $his !u"! outlet !ressure has a range -ro" 6 Pa (70 !si) to 25 Pa (626 !si)#
HEUI Injector (Components) $he 3EI inector seres -our -unctions# $he 3EI inector !ressuries su!!l' -uel -ro" 450 +Pa (65 !si) to 175 Pa (25400 !si)# $he 3EI inector -unctions as an ato"ier .' !u"!ing high !ressure -uel through ori-ice holes in the unit inector ti!# $he 3EI inector deliers the correct a"ount o- ato"ied -uel into the co".ustion cha".er and the 3EI inector dis!erses the ato"ied -uel eenl' throughout the co".ustion cha".er#
C9 arine Engine 9800001P(&E:P4250 ) ;ocu"entaci
Illustration 11 (40) &olenoid (41) %r"ature s!ring (42) %r"ature (4) &eated !in (44) &!ool s!ring (45) &!ool ale (46) Chec+ .all -or intensi-ier !iston
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(47) Intensifier piston (48) Return spring (49) Plunger (50) Barrel (51) Nozzle case (52) Inlet fill cec! (5") #top (54) Nozzle spring (55) $ec! piston (5%) #lee&e (57) Re&erse flo' cec! &al&e (58) Nozzle cec! (59) Nozzle tip
e *+I in,ector consists of tree -a,or parts. / +pper en or actuator () / 3ile or pu-ping unit (B) / o'er en or nozzle asse-l6 ($) e upper en () consists of te follo'ing ite-s. / #olenoi (40) / r-ature (42) / r-ature spring (41) / #pool &al&e (45) / #pool spring (44) / #eate pin (4") / $ec! all for intensifier piston (4%) e -ile of te in,ector (B) contains te follo'ing ite-s. / Intensifier piston (47) / Return spring (48) / Plunger (49) / Barrel (50)
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The lower end of the injector (C) consists of the following items: • Nozzle case (51) • Stop (53) • nlet fill chec! (5") • Slee#e (5$) • %e#erse flow chec! #al#e (5&) • Nozzle spring (5') • Chec! piston (55) • Nozzle chec! (5) • Nozzle tip (5) These components wor! together in order to prod*ce different rates for f*el injection+ The rates for f*el injection are electronicall, controlled -, performance software in the .C/+
Operation of HEUI Fuel Injector The 0. injector operates with a split injection c,cle+ The split injection c,cle has fi#e phases of injection: • 2reinjection • 2ilot injection • njection dela, • /ain injection • 4ill
Pre-Injection
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ll*stration 1" ('1) @rmat*re spring ('") @rmat*re ('3) Seated pin ('') Spool spring ('5) Spool #al#e ('&) ntensifier piston (') 2l*nger
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(55) Check piston (58) Nozzle check
The injector is in the phase of pre-injection when the engine is running and the injector is between firing cycles !lunger ("#) and the intensifier piston ("$) are at the top of the piston bore The ca%ity below the plunger is full of fuel &n the upper end' the arature (") and the seated pin ("*) are held down by the arature spring ("+) ,igh pressure actuation oil flows into the injector The oil then flows around the seated pin to the top of the check piston (55) This pro%ides a positi%e downward force on the nozzle check (58) at all ties when fuel is not being injected The spool %al%e ("5) is held in the top of the bore for the spool %al%e by the spool spring ("") &n this position' the spool %al%e blocks actuation oil fro reaching the intensifier piston ctuation pressure is felt on both the top and botto of the spool' so hydraulic forces on the spool are balanced The spool %al%e is held in the up position or the closed position by the force of the spool spring
Pilot Injection
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Illustration 13 (40) Solenoid (42) Armature (43) Seated pin (45) Spool valve (46) Ce!" #all $or intensi$ier piston (47) Intensi$ier piston (49) %lunger
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(54) Nozzle spring (55) Check piston (58) Nozzle check (59) Nozzle tip (60) Drain
Pilot injection occurs when the C! sen"s a control current to the solenoi" (40)# $he current creates a %agnetic &iel" which li&ts the ar%ature (4') an" the seate" pin (4)# $he seate" pin has a lower seat an" an upper seat# hen the seate" pin is li&te" *+ the ar%ature, the upper seat closes o&& the &low o& actuation pressure to the check# $he lower seat opens# $his allows the actuation oil on top o& check piston (55) to &low to "rain (60)# -ctuation oil that is trappe" *elow spool (45) will also &low to "rain (60)# $he actuation oil "rains through a .ent hole in the si"e o& the injector# $he "rop in pressure un"er the spool causes a h+"raulic "i&&erence that acts on the spool# $he spool %o.es into the open position when h+"raulic pressure acts on the top o& the spool# $his h+"raulic pressure &orces the spool "ownwar"# $he "ownwar" %o.e%ent o& the spool is stoppe" when the spool an" the pin &orce the check *all (46) &or the intensi&ier pi ston onto the *all seat in the close" position# $his pre.ents a n+ actuation pressure &ro% escaping &ro% the ca.it+ &or the intensi&ier piston (4/)# $his "rop in the actuation pressure also re%o.es the "ownwar" &orce on the check pis ton# -ctuation oil now &lows past the open spool an" to the top o& the intensi&ier piston# $he "ownwar" %o.e%ent o& the piston an" plunger (49) pressurizes the &uel in the plunger ca.it+ to the nozzle tip (59)# Pilot injection *egins when the injection pressure increases in or"er to o.erco%e the &orce o& the nozzle spring (54) which li&ts the nozzle check (58) # Pilot injection will continue i& the &ollowing con"itions eist1 2 $he solenoi" is energize"# 2 $he spool re%ains open# 2 $here is no actuation pressure on top o& the check piston#
Injection Delay
C9 !arine ngine 900007P(:P4'50 7 8) 7 Docu%entaci;n
@llustration 4 (40) olenoi" (4) -r%ature spring (4') -r%ature (4) eate" pin (44) pool spring (45) pool .al.e (4/) @ntensi&ier piston
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P3gina '4 "e '9
C9 1arine 2ngine 39!!!!*"P(627P4&5! " +8) " ocu%entacin
P0gina &5 de &9
(49) Plunger (55) Check piston (58) Nozzle check
Injection delay begins hen the control current to the solenoid (4!) stops and the solenoid is de"energized# $he ar%ature (4&) is held in the up position by a %agnetic 'ield# hen the %agnetic 'ield is de"energized the ar%ature spring (4*) pushes the ar%ature and the seated pin (4+) donard# $he seated pin closes the loer seat and the seated pin opens the upper seat# $his allos the actuation pressure to 'lo to the top o' the check piston (55)# $he hydraulic 'orce on the check piston ,uickly o-erco%es the injection pressure and the nozzle check (58) closes# Injection stops at this point# .ctuation pressure increases under the spool -al-e (45) that creates the balance o' hydraulic 'orce on the top and botto% o' the spool# $he eak spool spring (44) no acts on the spool# $his closes the spool -ery sloly# .s the spool re%ains open actuation pressure continues to 'lo past the spool to intensi'ier piston (4/) and to plunger (49)# $he injection pressure in the nozzle and in the plunger ca-ity increases -ery ,uickly hen the nozzle check is held in the closed position#
Main Injection
9 *arine +ngine ,9-00001./(S+4250 . 38) . o"umenta"in
Illustration 15 (40) Solenoid (42) Armature (43) Seated pin (45) Spool valve (46) !e"# $all %or intensi%ier piston (55) !e"# piston (58) &o''le "!e"#
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, Marine ngine /,00001-2(34!%0 - #&) - Docmentaci5n
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(60) Drain
Main injection begins when the solenoid (40) is re-energized. The magnetic field is ins tantly created and the force of the magnetic field lifts the armatre (4!) and the seated "in (4#). The ""er seat closes off the flow of actation "ressre and the ""er seat o"ens the chec$ "iston (%%) and the bottom of the s"ool (4%) to the drain (60). The hydralic force that holds the nozzle chec$ (%&) closed 'ic$ly dissi"ates and the injection "ressre o"ens the nozzle chec$. This is the start of main injection. difference in hydralic forces on the s"ool is also created. This difference forces the s"ool downward. The chec$ ball (46) for the intensifier "iston is held in the closed "osition when the s"ool is in this "osition. Main injection contines if the solenoid remains energized. Fill
, Marine ngine /,00001-2(34!%0 - #&) - Docmentaci5n
;llstration 16 (40) 3olenoid (41) rmatre s"ring (4!) rmatre (4#) 3eated "in (44) 3"ool s"ring (4%) 3"ool
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C9 3arine ngine 96""""-P(P4+5" ,8) #ocu*entaci:n
P2gina +9 'e +9
(47) Intensifier Piston (48) Return spring (49) Plunger (55) Check piston (57) Reverse flow check valve (58) Nole check (!") #rain
$he fill c%cle &egins when the solenoi' (4") is 'eenergie' $he ar*ature (4+) an' the seate' pin (4,) are force' 'own &% the ar*ature spring (4-) $he seate' pin closes the lower seat an' the seate' pin opens the upper seat .ctuation pressure is restore' to the top of the check piston (55) $his closes the nole check (58) an' in/ection en's .ctuation pressure is also felt un'er the valve spool (45) $his restores the h%'raulic &alance on the spool $he valve spring (44) slowl% closes the spool $his stops the flow of actuation oil to the intensifier piston (47) .s the spool raises0 the check &all (4!) for the intensifier piston is no longer hel' close' 1il in the cavit% for the intensifier piston lifts the check off the seat an' flows to the 'rain (!") through a vent hole in the si'e of the in/ector Return spring (48) pushes up plunger (49) an' the intensifier piston $his pushes all of the oil out of the cavit% for the intensifier piston $he check valve (57) for the fuel inlet is taken off of the valve seat as the plunger lifts up $his allows suppl% fuel to flow into the plunger cavit% $he fill c%cle is co*plete when the plunger an' the piston are at the top of the &ore an' the plunger cavit% is full of fuel Copyright 1993 - 2015 Caterpillar Inc. Todos los derechos reservados. Red privada para licenciados del SIS.
Thu ar 5 0!"#0"5$ %ST 2015 r0!0es10
