common rail fuel injection system
DESCRIPTION
COMMON RAIL FUEL INJECTION SYSTEM. ;JL";L\U V[g0 VMJZ CM,L\U VMO VM8MDMAF., s 0Lh, f] ,[XG G\AZ : 15. Demand On Modern Diesel Engine Development. Low fuel consumption Low pollutant emissions Quiet running engines Improved engine performance. - PowerPoint PPT PresentationTRANSCRIPT
COMMON RAIL FUEL INJECTION COMMON RAIL FUEL INJECTION SYSTEMSYSTEM
;JL";L\U V[g0 VMJZ CM,L\U VMO VM8MDMAF., s 0Lh,
f],[XG G\AZ : 15
Demand On Modern Diesel Engine Demand On Modern Diesel Engine Development Development
Low fuel consumptionLow fuel consumption
Low pollutant emissionsLow pollutant emissions
Quiet running enginesQuiet running engines
Improved engine performanceImproved engine performance
Common rail fuel injection system and its Common rail fuel injection system and its functionfunction
Provide the diesel engine with fuelProvide the diesel engine with fuel Generate the high pressure needed for fuel Generate the high pressure needed for fuel
injection and distribute the fuel to the injection and distribute the fuel to the individual cylindersindividual cylinders Inject precisely correct amount of fuel at Inject precisely correct amount of fuel at exactly the right moment in time.exactly the right moment in time. In contrast to other injection system Common In contrast to other injection system Common rail fuel injection system is an accumulator rail fuel injection system is an accumulator
injection system.injection system.
How does a CR system function?How does a CR system function?
Sub functions of a CRFI system
Low pressure c ircuit H igh pressure c ircuit ECU w ith sensors
COM M ON RAIL FUEL INJECTION SYSTEM
Low –pressure circuit comprises of:Low –pressure circuit comprises of:Fuel tank ,Pre-supply pump, Fuel filter, And the Fuel tank ,Pre-supply pump, Fuel filter, And the
respective connection lines.respective connection lines.
The Common Rail Sub functionsThe Common Rail Sub functions
Low –pressure circuitLow –pressure circuitThe low –pressure circuit is responsible for The low –pressure circuit is responsible for
transporting the fuel to the high –pressure circuittransporting the fuel to the high –pressure circuit
High –pressure circuit comprises:High –pressure circuit comprises:High – pressure pump with pressure – control valve High – pressure pump with pressure – control valve The high – pressure accumulator (Rail )with the rail –pressure The high – pressure accumulator (Rail )with the rail –pressure sensorsensorInjectors, and Injectors, and The respective high – pressure connection lines.The respective high – pressure connection lines.
The Common Rail Sub functionsThe Common Rail Sub functions
The high – pressure circuitThe high – pressure circuit
It is the responsibility of the highIt is the responsibility of the highpressure circuit to generate a constantpressure circuit to generate a constantunvarying high pressure in the highunvarying high pressure in the highpressure accumulator (the rail) and topressure accumulator (the rail) and toinject the fuel through the injectors intoinject the fuel through the injectors intothe engine’s combustion chambers.the engine’s combustion chambers.
ECU and sensorsECU and sensorsThe common rail ECU evaluates the signals from the The common rail ECU evaluates the signals from the
following sensors.following sensors. Crankshaft – speed sensor, Camshaft sensor,Crankshaft – speed sensor, Camshaft sensor, Accelerator-pedal travel sensorAccelerator-pedal travel sensor
The Common Rail Sub functionsThe Common Rail Sub functions
The common rail ECU evaluates the signals from the The common rail ECU evaluates the signals from the following sensors:following sensors:
Boost – pressure sensor, Air temperature sensor,Boost – pressure sensor, Air temperature sensor, Air – mass meter, and Rail pressure sensor.Air – mass meter, and Rail pressure sensor.
The Common Rail Sub functionsThe Common Rail Sub functions
The Common Rail Sub functionsThe Common Rail Sub functionsECU and sensorsECU and sensorsThe sensor are responsible for measuring important The sensor are responsible for measuring important
physical quantities. The ECU calculates injected fuel physical quantities. The ECU calculates injected fuel quantity, start of injection, duration of injection, and quantity, start of injection, duration of injection, and rate of discharge curve, as well supervises the correct rate of discharge curve, as well supervises the correct functioning of the injection system as a whole.functioning of the injection system as a whole.
PRE SUPPLY PUMPPRE SUPPLY PUMPTransports fuel from the fuel tank to the high pressure Transports fuel from the fuel tank to the high pressure pump.pump.An electric fuel pump is used for this purpose in the An electric fuel pump is used for this purpose in the CRFIS.CRFIS.When the electric fuel pump is switched off, the supply When the electric fuel pump is switched off, the supply of fuel is interrupted and the engine stops.of fuel is interrupted and the engine stops.
COMMON RAIL FUEL INJECTION SYSTEMCOMMON RAIL FUEL INJECTION SYSTEM
DESIGNDESIGN
PRE SUPPLY PUMPPRE SUPPLY PUMP
The electric fuel pump comprises of:The electric fuel pump comprises of:1.Electric Motor1.Electric Motor2.Roller-Cell Pump2.Roller-Cell Pump3.Non Return Valve3.Non Return Valve
The roller cell is The roller cell is driven by an electric driven by an electric motor.motor.Its rotor is mounted Its rotor is mounted eccentrically and eccentrically and provided with slots provided with slots in which movable in which movable rollers are free to rollers are free to travel.travel.
PRE SUPPLY PUMPPRE SUPPLY PUMP
The rollers are forced The rollers are forced against the base plate against the base plate by rotation and by fuel by rotation and by fuel pressure .pressure . The fuel is The fuel is transported to the transported to the outlet openings on the outlet openings on the pump’s pressure side.pump’s pressure side.
PRE SUPPLY PUMPPRE SUPPLY PUMP
Gear type fuel pumpGear type fuel pump The drive gear The drive gear
wheel is driven by wheel is driven by the engine .the engine .
Delivery quantity is Delivery quantity is directly proportional directly proportional to engine speed .to engine speed .
Shut off is by means Shut off is by means of an of an electromagnet..electromagnet..
PRE SUPPLY PUMPPRE SUPPLY PUMPvariantsvariants
High- pressure pumpHigh- pressure pump The pump plunger moves downwards The pump plunger moves downwards The inlet valve opens The inlet valve opens The fuel is drawn in to the pumping element The fuel is drawn in to the pumping element
chamber(suction stroke)chamber(suction stroke)
At BDC, the inlet valve closes At BDC, the inlet valve closes The fuel in the chamber can be compressed by The fuel in the chamber can be compressed by
the upward moving plunger.the upward moving plunger.
High- pressure pumpHigh- pressure pump
An electromagnet is An electromagnet is used for pumping used for pumping element switch-off.element switch-off.
High- pressure pumpHigh- pressure pump
High- pressure accumulator (Rail)High- pressure accumulator (Rail)Store fuelStore fuelPrevent pressure fluctuationsPrevent pressure fluctuations
Rail is a forged-steel tube.Rail is a forged-steel tube.ID is approx.. 10mmID is approx.. 10mmLength is between 280 and 600mmLength is between 280 and 600mm
The volume must be “ as small as possible, The volume must be “ as small as possible, as large as necessary”as large as necessary”
High- pressure accumulator (Rail)High- pressure accumulator (Rail)
Pressure-control valve (DRV)Pressure-control valve (DRV)
Responsible for Responsible for maintaining the maintaining the pressure in the pressure in the rail at a rail at a constant level.constant level.
Rail-pressure sensor (RDS)Rail-pressure sensor (RDS)
Measures the Measures the pressure in the railpressure in the railinputs the information inputs the information to the ECUto the ECU
RDS should RDS should provide provide extremely extremely precise precise measured measured values.values.RDS is mounted RDS is mounted directly on the directly on the rail.rail.
InjectorInjectorInjects exactly the correct amount of fuel in Injects exactly the correct amount of fuel in to the combustion chamber at precisely to the combustion chamber at precisely the right moment in timethe right moment in time
The injector is equipped with:The injector is equipped with:2/2 electromagnetic servo valve2/2 electromagnetic servo valveNozzleNozzleValve control chamberValve control chamberReturn lineReturn line
InjectorInjector
The essential forces for correct functioning are:The essential forces for correct functioning are: Nozzle-spring forceNozzle-spring force Valve spring forceValve spring force Electromagnet forceElectromagnet force Force due to the pressure in the valve-control Force due to the pressure in the valve-control
chamber chamber Force due to the pressure in the nozzle needleForce due to the pressure in the nozzle needle
InjectorInjector
ECU with sensorsECU with sensors
Common Rail is an EDC controlled injection Common Rail is an EDC controlled injection systemsystemThe ECU controls & monitors the complete The ECU controls & monitors the complete injection processinjection processThe sensors delivers all the measured values The sensors delivers all the measured values which are required in the processwhich are required in the process
SummaryComponents of CRFIS are:Components of CRFIS are: Pre-supply pumpPre-supply pump High-pressure pumpHigh-pressure pump High-pressure High-pressure
accumulator(rail)accumulator(rail)Pressure-control Pressure-control valvevalveRail-pressure sensorRail-pressure sensorInjectorsInjectorsECU with sensorsECU with sensors
COMMON RAIL FUEL INJECTION COMMON RAIL FUEL INJECTION SYSTEMSYSTEM
COMMON RAIL FUEL INJECTION SYSTEMCOMMON RAIL FUEL INJECTION SYSTEM SUMMARSUMMAR1.The basic functional groups of the common rail are : low 1.The basic functional groups of the common rail are : low
– pressure circuit , high – pressure circuit ECU and – pressure circuit , high – pressure circuit ECU and sensors.sensors.
2.In the low – pressure circuit, the fuel is cleaned by a filter 2.In the low – pressure circuit, the fuel is cleaned by a filter and then transported to the high – pressure circuitand then transported to the high – pressure circuit
COMMON RAIL FUEL INJECTION SYSTEMCOMMON RAIL FUEL INJECTION SYSTEM
SUMMARYSUMMARY3.In the high – pressure circuit , the maximum 3.In the high – pressure circuit , the maximum
pressure of 1,350 bar is generated in the high – pressure of 1,350 bar is generated in the high – pressure accumulator (Rail).pressure accumulator (Rail).
The pressure is maintained at a constant The pressure is maintained at a constant level , and the fuel is taken from the rail every level , and the fuel is taken from the rail every time an injection takes place.time an injection takes place.
4.The ECU controls and monitors the complete 4.The ECU controls and monitors the complete injection system. Using the signals from the injection system. Using the signals from the sensors, the ECU calculates all the values for sensors, the ECU calculates all the values for the injection process and triggers the the injection process and triggers the components in high-pressure circuit (pressure – components in high-pressure circuit (pressure – control valve, injectors). control valve, injectors).