Land Rover Common Rail System Crs Denso Manual

							Operation Section1–6
1.7 Common Rail System Configuration
zThe common rail control system can be broadly divided into the following four areas: sensors, engine ECU, EDU, and
actuators.
Sensors
zDetect the condition of the engine and the pump.
Engine ECU
zReceives signals from the sensors, calculates the proper injection quantity and injection timing for optimal engine oper-
ation, and sends the appropriate signals to the actuators.
EDU
zEnables the injectors to be actuated at high speeds. There are also types with charge circuits within the ECU that serve
the same role as the EDU. In this case, there is no EDU.
Actuators
zOperate to provide optimal injection quantity and injection timing in accordance with the signals received from the en-
gine ECU.
Engine Speed Sensor / 
TDC (G) Sensor
Accelerator Position Sensor
Other Sensors 
and SwitchesEngine ECUEDUSupply Pump 
(SCV: Suction Control Valve)
Injector
Other Actuators
DiagnosisQ000754E 
						

							Operation Section1–7
2.  COMMON RAIL SYSTEM OUTLINE
2.1 Layout of Main Components
zCommon rail systems are mainly made up of the supply pump, rail, and injectors. There are the following types accord-
ing to the supply pump used.
(1) HP0 Type
• This system is the first common rail system that DENSO commercialized. It uses an HP0 type supply pump and is
mounted in large trucks and large buses.
Exterior View of Main System Components
Configuration of Main System Components (Example of HP0)
Q000755E
InjectorSupply Pump (HP0 Type)
Rail
Q000756E
Supply PumpPCV (Pump Control Valve)
Cylinder 
Recognition Sensor 
(TDC (G) Sensor)
Rail Pressure Sensor Rail Engine ECU
Injector Accelerator 
Position Sensor
Crankshaft Position Sensor (Engine Speed Sensor)Fuel Temperature 
Sensor
Coolant Temperature 
Sensor 
						

							Operation Section1–8
(2) HP2 Type
• This system uses a type of HP2 supply pump that has been made lighter and more compact, and is the common rail
system for passenger cars and RVs instead of the ECD-V3.
Exterior View of Main System Components
Mounting Diagram of Main System Components
Q000757E
InjectorSupply Pump (HP2 Type)
Rail
Engine ECU
EDU (Electronic Driving Unit) EGR Valve
E-VRV
Intake Air Temperature 
SensorIntake Air  Pressure  Sensor
Injector
Crankshaft Position Sensor 
(Engine Speed Sensor)
Rail
Supply PumpCylinder Recognition Sensor
(TDC (G) Sensor)Rail Pressure Sensor Accelerator Position Sensor
Coolant Temperature 
Sensor
Q000758E 
						

							Operation Section1–9
Overall System Flow (Fuel)
Q000926E
Supply Pump
Plunger Feed PumpDelivery Valve
SCV 
(Suction 
Control 
Va lve)
Inner Cam Regulating Valve
Check Valve
Rail
Rail Pressure Sensor
Pressure 
Limiter
InjectorTWV Engine 
ECUEDU
Various Sensors
Fuel Filter
Fuel Tank
: Flow of Injection Fuel
: Flow of Leak Fuel 
						

							Operation Section1–10
(3) HP3 Type, HP4 Type
HP3 Type
• This system uses an HP3 type supply pump that is compact, lightweight and provides higher pressure.  It is mostly
mounted in passenger cars and small trucks.
HP4 Type
• This system is basically the same as the HP3 type, however it uses the HP4 type supply pump, which has an in-
creased pumping quantity to handle larger engines. This system is mostly mounted in medium-size trucks. 
Exterior View of Main System Components
Mounting Diagram for Main System Components
Q000759E
HP3HP4
InjectorSupply Pump 
Rail
Q000760E
Supply Pump
SCV 
(Suction Control 
Valve)Fuel Temperature 
Sensor Fuel Temperature 
Sensor
InjectorEngine ECU
EDUDLC3 Connector
R/B EGR Valve
E-VRV for EGR
EGR Shut-Off VSVThrottle Body
Crankshaft Position Sensor
 (Engine Speed Sensor)
Cylinder Recognition Sensor
 (TDC (G) Sensor)Accelerator Position Sensor Intake Air 
Pressure 
Sensor
Airflow Meter 
(with Intake Air 
Temperature Sensor)
Coolant Temperature Sensor
HP3 HP4
(Suction Control 
Valve) SCV 
Pressure Discharge Valve
Rail Pressure Sensor 
						

							Operation Section1–11
Overall System Flow (Fuel)
Q000927E
Supply Pump 
(HP3 or HP4)
Plunger
Feed PumpDelivery 
Va l v e
SCV 
(Suction 
Control Valve)
Rail
Rail Pressure SensorPressure Discharge Valve
Pressure Limiter
Injector ECUEDU
Various 
Sensors
Fuel Filter
Fuel Tank
: Flow of Injection Fuel
: Flow of Leak Fuel 
						

							Operation Section1–12
3. SUPPLY PUMP DESCRIPTION
3.1 HP0 Type
(1) Construction and Characteristics
• The HP0 supply pump is mainly made up of a pumping system as in conventional in-line pumps (two cylinders), the
PCV (Pump Control Valve) for controlling the fuel discharge quantity, the cylinder recognition sensor {TDC (G) sen-
sor}, and the feed pump.
• It supports the number of engine cylinders by changing the number of peaks on the cam. The supply pump rotates at
half the speed of the engine. The relationship between the number of engine cylinders and the supply pump pumping
is as shown in the table below.
• By increasing the number of cam peaks to handle the number of engine cylinders, a compact, two-cylinder pump unit
is achieved. Furthermore, because this pump has the same number of pumping strokes as injections, it maintains a
smooth and stable rail pressure.
Number of Engine CylindersSpeed Ratio 
(Pump: Engine)Supply PumpNumber of Pumping Rotations for 1 
Cycle of the Engine (2 Rotations)Number of 
CylindersCam Peaks
4 Cylinders
1 : 2 224
6 Cylinders 3 6
8 Cylinders 4 8
Feed Pump Delivery Valve
Cam x 2PCV (Pump Control Valve)
TappetElement
Cylinder Recognition Sensor
 (TDC (G) Sensor)
Pulsar for TDC (G) SensorOverflow Valve
Q000768E 
						

							Operation Section1–13
(2) Exploded View
Q000769E
PCV 
(Pump Control Valve)
Delivery Valve
Element
Cylinder Recognition Sensor
(TDC (G) Sensor)
Roller Cam
CamshaftTappet
Feed Pump Priming Pump  
						

							Operation Section1–14
(3) Supply Pump Component Part Functions
Feed Pump
• The feed pump, which is integrated in the supply pump, draws fuel from the fuel tank and feeds it to the pump chamber
via the fuel filter. There are two types of feed pumps, the trochoid type and the vane type.
Trochoid Type
- The camshaft actuates the outer/inner rotors of the feed pump, causing them to start rotating. In accordance with
the space produced by the movement of the outer/inner rotors, the feed pump draws fuel into the suction port and
pumps fuel out the discharge port.
Va ne  Ty p e
- The camshaft actuates the feed pump rotor and the vanes slide along the inner circumference of the eccentric ring.
Along with the rotation of the rotor, the pump draws fuel from the fuel tank, and discharges it to the SCV and the
pumping mechanism.
Component PartsFunctions
Feed Pump Draws fuel from the fuel tank and feeds it to the pumping mechanism.
Overflow Valve Regulates the pressure of the fuel in the supply pump.
PCV (Pump Control Valve) Controls the quantity of fuel delivered to the rail.
Pumping 
MechanismCam Actuates the tappet.
Tappet Transmits reciprocating motion to the plunger.
Plunger Moves reciprocally to draw and compress fuel.
Delivery Valve Stops the reverse flow of fuel pumped to the rail.
Cylinder Recognition Sensor {TDC (G)
Sensor}Identifies the engine cylinders.
To Pump Chamber
From Fuel TankOuter Rotor
Inner Rotor Suction PortDischarge Port
Q000770E
Suction PortDischarge Port
Rotor
Eccentric Ring
Va n e
Q000771E 
						

							Operation Section1–15
PCV: Pump Control Valve
• The PCV (Pump Control Valve) regulates the fuel discharge quantity from the supply pump in order to regulate the
rail pressure. The fuel quantity discharged from the supply pump to the rail is determined by the timing with which the
current is applied to the PCV.
Actuation Circuit
- The diagram below shows the actuation circuit of the PCV. The ignition switch turns the PCV relay ON and OFF to
apply current to the PCV. The ECU handles ON/OFF control of the PCV. Based on the signals from each sensor,
it determines the target discharge quantity required to provide optimum rail pressure and controls the ON/OFF tim-
ing for the PCV to achieve this target discharge quantity.
Pumping Mechanism
• The camshaft is actuated by the engine and the cam actuates the plunger via the tappet to pump the fuel sent by the
feed pump. The PCV controls the discharge quantity. The fuel is pumped from the feed pump to the cylinder, and then
to the delivery valve.
PCV
Ignition Switch
+B PCV Relay
PCV1
PCV2From PCV relay
To Rail
Q000772E
Q000773E
Camshaft
Feed PumpPCV (Pump Control Valve)
Pulsar for TDC (G) SensorDelivery Valve
Cam (3 Lobes:  6-Cylinders) Plunger
To Rail