Land Rover Common Rail System Crs Denso Manual

							Operation Section1–16
CYLINDER RECOGNITION SENSOR {TDC (G) SENSOR}
• The cylinder recognition sensor {TDC (G) sensor} uses the alternating current voltage generated by the change in the
lines of magnetic force passing through the coil to send the output voltage to the ECU. This is the same for the engine
speed sensor installed on the engine side. A disc-shaped gear, which is provided in the center of the supply pump
camshaft, has cutouts that are placed at 120? intervals, plus an extra cutout. Therefore, this gear outputs seven puls-
es for every two revolutions of the engine (for a six-cylinder engine). Through the combination of engine-side engine
speed pulses and TDC pulses, the pulse after the extra cutout pulse is recognized as the No. 1 cylinder.
Q000774E
024681012140246810 12  14 0 2 4 6 8 10  12 0 24681012140246810121402468 02468 1012
Cylinder Recognition Sensor 
(TDC (G) Sensor)
No.6 Cylinder TDC (G) Standard Pulse
No.1 Cylinder Recognition TDC (G) Pulse
No.1 Cylinder TDC (G) Pulse
No.1 Cylinder Engine Speed Standard Pulse
No.6 Cylinder Engine Speed Standard Pulse
· TDC (G) Pulse
· Engine Speed Pulse
· For a 6-Cylinder Engine (Reference) 
						

							Operation Section1–17
(4) Supply Pump Operation
Supply Pump Overall Fuel Flow
• The fuel is drawn by the feed pump from the fuel tank and sent to the pumping mechanism via the PCV. The PCV
adjusts the quantity of fuel pumped by the pumping mechanism to the necessary discharge quantity, and the fuel is
pumped to the rail via the delivery valve.
Fuel Discharge Quantity Control
• The fuel sent from the feed pump is pumped by the plunger. In order to adjust the rail pressure, the PCV controls the
discharge quantity. Actual operation is as follows.
PCV and Plunger Operation During Each Stroke
Intake Stroke (A) In the plungers descent stroke, the PCV opens and low-pressure fuel is suctioned into the
plunger chamber via the PCV.
Pre-Stroke (B) Even when the plunger enters its ascent stroke, the PCV remains open while it is not energized.
During this time, fuel drawn in through the PCV is returned through the PCV without being pres-
surized (pre-stroke).
Pumping Stroke (C) At a timing suited to the required discharge quantity, power is supplied to close the PCV, the
return passage closes, and pressure in the plunger chamber rises. Therefore, the fuel passes
through the delivery valve (reverse cut-off valve) and is pumped to the rail. Specifically, the
plunger lift portion after the PCV closes becomes the discharge quantity, and by varying the tim-
ing for the PCV closing (the end point of the plunger pre-stroke), the discharge quantity is varied
to control the rail pressure.
Intake Stroke (A) When the cam exceeds the maximum lift, the plunger enters its descent stroke and pressure in
the plunger chamber decreases. At this time, the delivery valve closes and fuel pumping stops. In
addition, the PCV opens because it is de-energized, and low-pressure fuel is suctioned into the
plunger chamber. Specifically, the system goes into state A.
Q000775E
Cam Lift
PCV Operation Close Valve
Intake Stroke Pumping Stroke 
Pre-Stroke 
Open Valve
PCV Pump Operation
PlungerReturn
When Discharge 
Quantity IncreasesWhen Discharge 
Quantity Decreases
To Rail
Pumping the Required 
Discharge Quantity
H
Discharge Quantity
h
Q=4
2d(H-h)
(A) (B) (C)(A)
Delivery Valve
From Fuel Tank
Pumping 
Mechanism
d 
						

							Operation Section1–18
3.2 HP2 Type
(1) Construction and Characteristics
• The supply pump is primarily composed of the two pumping mechanism (inner cam, roller, two plungers) systems,
the SCV (Suction Control Valve), the fuel temperature sensor, and the feed pump (vane type), and is actuated with
half the engine rotation.
• The pumping mechanism consists of an inner cam and a plunger, and forms a tandem configuration in which two sys-
tems are arranged axially. This makes the supply pump compact and reduces the peak torque.
• The quantity of fuel discharged to the rail is controlled by the fuel suction quantity using SCV (Suction Control Valve)
control. In order to control the discharge quantity with the suction quantity, excess pumping operations are eliminated,
reducing the actuation load and suppressing the rise in fuel temperature.
Regulating Valve
PlungerFeed Pump
Inner Cam Roller Fuel Temperature Sensor
Delivery Valve
SCV 
(Suction Control 
Valve)
Check ValveOverflow
Fuel Suction (From Fuel Tank)
Q000818E 
						

							Operation Section1–19
(2) Supply Pump Actuating Torque
• Because the pumping mechanism is a tandem configuration, its peak actuating torque is one-half that of a single
pump with the same discharge capacity.
Pumping
Pumping
Pumping SuctionPumping
Feed
Feed Plunger 2 Plunger 1
Torque (Oil Pumping Rate) Torque (Oil Pumping Rate)
 Composition
Single TypeTandem Type
Torque Pattern 
Solid Line    : Plunger 1
Broken Line: Plunger 2
Q000819E 
						

							Operation Section1–20
(3) Exploded View
Pump Body
Feed PumpCamshaft
Inner Cam
Roller
Shoe
Delivery Valve
SCV (Suction Control Valve)
Check Valve Fuel Temperature Sensor Regulating Valve
Q000820E 
						

							Operation Section1–21
(4) Component Part Functions
Feed Pump
• The feed pump is a four-vaned type that draws fuel from the fuel tank and discharges it to the pumping mechanism.
The rotation of the drive shaft causes the feed pump rotor to rotate and the vane to move by sliding along the inner
surface of the casing (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. To keep the vane pressed against the inner circumference, a
spring is provided inside each vane, in order to minimize fuel leakage within the pump.
Regulating Valve
• The purpose of the regulating valve is to control the feed pressure (fuel pumping pressure) sending fuel to the pump-
ing mechanism. As the rotational movement of the pump increases and the feed pressure exceeds the pressure set
at the regulating valve, the valve opens by overcoming the spring force, allowing the fuel to return to the suction side.
Component PartsFunctions
Feed Pump Draws fuel from the fuel tank and feeds it to the pumping mechanism.
Regulating Valve Regulates internal fuel pressure in the supply pump.
SCV (Suction Control Valve) Controls  the  quantity  of  fuel that is fed to the plunger in order to control fuel
pressure in the rail.
Pumping 
MechanismInner Cam Actuates the plunger.
Roller Actuates the plunger.
Plunger Moves reciprocally to draw and compress fuel.
Delivery Valve Maintains high pressure by separating the pressurized area (rail) from the
pumping mechanism.
Fuel Temperature Sensor Detects the fuel temperature.
Check Valve Prevents the pressurized fuel in the pumping mechanism from flowing back
into the suction side.
Q000821E
Rotor Eccentric Ring
Spring
Vane
Front Cover
Rear Cover
Regulating Valve
Open Valve Pressure Characteristic
Open Valve 
Pressure High
Open Valve 
Pressure Low
Speed
Feed Pressure
 (Pumping Pressure)
Regulating Valve
Feed Pump
 (Discharge Side)Suction Inlet
Filter
Feed Pump 
(Suction Side)Regulating Valve Body
Spring
Piston
Bushing
Q000822E 
						

							Operation Section1–22
SCV: Suction Control Valve 
• A solenoid type valve has been adopted. The ECU controls the duration of the current applied to the SCV in order to
control the quantity of fuel drawn into the pumping mechanism. Because only the quantity of fuel required to achieve
the target rail pressure is drawn in, the actuating load of the supply pump decreases, thus improving fuel economy.
SCV ON
- When current is applied to the coil, it pulls the needle valve upward, allowing fuel to be drawn into the pumping
mechanism of the supply pump.
SCV OFF
- When current is no longer applied to the coil, the needle valve closes and stops the suction of fuel.
Needle Valve
Spring
StopperCoil
Q000823E
To Pump Pumping Mechanism
From Feed Pump
Q000824E
From Feed PumpQ000825E 
						

							Operation Section1–23
Pumping Mechanism (Plunger, Inner Cam, Roller)
• The pumping mechanism is made up of the plunger, inner cam, and roller, and it draws in the fuel discharged by the
feed pump and pumps it to the rail. Because the drive shaft and the inner cam have an integral construction, the ro-
tation of the drive shaft directly becomes the rotation of the inner cam.
• Two plunger systems are arranged in series (tandem type) inside the inner cam. Plunger 1 is situated horizontally,
and plunger 2 is situated vertically. Plunger 1 and plunger 2 have their suction and compression strokes reversed
(when one is on the intake, the other is discharging), and each plunger discharges twice for each one rotation, so for
one rotation of the supply pump, they discharge a total of four times to the rail.
Delivery Valve
• The delivery valve, which contains two valve balls, delivers the pressurized fuel from plungers 1 and 2 to the rail in
alternating strokes. When the pressure in the plunger exceeds the pressure in the rail, the valve opens to discharge
fuel.
Inner Cam 
(Cam Lift: 3.4mm)Roller
Roller Diameter:    9
Roller Length: 21mm
Material: Reinforced Ceramic
Plunger 1 
(Horizontal)Plunger 2 
(Vertical)
· Plunger 1: Medium + Medium
· Plunger 2: Short + Long
Plunger Length Combination
Cam 90  Rotation
Plunger 1: Start of Pumping
Plunger 2: Start of Suction Plunger 1: Start of Suction
Plunger 2: Start of PumpingPlunger 1
Plunger 2
Q000826E
From Plunger 1
From Plunger 2
Pin
GasketGuide
Valve BallStopper HolderTo Rail
· When Plunger 1 Pumping · When Plunger 2 Pumping
Q000827E 
						

							Operation Section1–24
Fuel Temperature Sensor
• The fuel temperature sensor is installed on the fuel intake side and utilizes the characteristics of a thermistor in which
the electric resistance changes with the temperature in order to detect the fuel temperature.
Check Valve
• The check valve, which is located between the SCV (Suction Control Valve) and the pumping mechanism, prevents
the pressurized fuel in the pumping mechanism from flowing back into the SCV.
Check Valve Open
- During fuel suction (SCV ON), the feed pressure opens the valve, allowing fuel to be drawn into the pumping mech-
anism.
Check Valve Closed
- During fuel pumping (SCV OFF), the pressurized fuel in the pumping mechanism closes the valve, preventing fuel
from flowing back into the SCV.
Resistance - Temperature 
Characteristic
Temperature Resistance Value
Thermistor
Q000828E
Pump Housing Spring Valve
Stopper PlugTo SCV To Pumping Mechanism
Q000829E
From SCV To Pumping MechanismQ000830E
From Pumping Mechanism
Q000831E 
						

							Operation Section1–25
(5) Supply Pump Operation
Supply Pump Overall Fuel Flow
• Fuel is suctioned by the feed pump from the fuel tank and sent to the SCV. At this time, the regulating valve adjusts
the fuel pressure to below a certain level. Fuel sent to the feed pump has the required discharge quantity adjusted by
the SCV and enters the pumping mechanism through the check valve. The fuel pumped by the pumping mechanism
is pumped through the delivery valve to the rail.
From Fuel Tank
Feed Pump
PlungerCam
Head
SCV2 Check Valve 1
Check Valve 2SCV1 To Rail Delivery Valve
To Tank Overflow Orifice 
Regulating Valve
Q000832E