Land Rover Lesson 2 Auto Trans Coolingine Rover Manual

							Component Locations
High-pressure (HP) fuel rail (2 of)1
HP pipe - Fuel rail to injector (6 of)2
Injectors (6 of)3
Low Pressure (LP) pipe - Fuel return4
HP pipe - High Pressure Pump (HPP) to fuel
diverter rail
5
LP pipe - Injector leak-back6
Connector to injector (part of 6)7
HPP8
HPP pulley9
HP diverter rail10
Rear Engine Accessory Drive (READ) belt
tensioner
11
LH exhaust camshaft pulley12
GENERAL
The TdV6 is equipped with a High-Pressure (HP)
common rail fuel injection system. With this fuel
injection process, a High-Pressure Pump (HPP) delivers
a uniform level of pressure to the shared fuel lines (the
common rails), which serve all six fuel injectors.
Pressure is controllable, to the optimum level for smooth
operation, up to 1650 bar.
The common rail system supports a pre-injection (pilot)
phase, which reduces combustion noise and mechanical
load.
Fuel injection pressure is generated independently of
engine speed and fuel injection events.
The fuel injection timing and volume are calculated by
the Engine Control Module (ECM), which then
energizes the appropriate piezo actuated injector.
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							The common rail fuel injection system has the following
features:
•High fuel injection pressures of up to 1650 bar for
greater atomisation of fuel (increasing performance
and lowering emissions)
•Variable injection to optimise combustion in all
engine operating conditions
•Low tolerances and high precision throughout the
life of the system
The fuel system is divided into 2 sub systems:
•Low-Pressure (LP) system
•HP system.
The LP system features the following components:
•In-tank fuel pump
•Fuel pressure regulator (integral to the fuel delivery
module)
•Fuel filter
•Return pipes and fuel cooler
•Injector return pipes
•Fuel coolers (engine and vehicle)
The LP system pressure is regulated to 0.5 bar.
The HP system features the following components:
•HPP
•Common rails and diverter rail
•HP fuel pipes
•Injectors.
LP SYSTEM
In-tank Fuel Pump
The electric fuel pump is located inside the fuel tank.
Fuel is pumped from the tank via the in-tank fuel pump,
to the HPP via the fuel filter.
Fuel Filter
The fuel filter is located in the engine compartment on
the left hand side, packaged to be protected against
damage. Incorporated in the fuel filter housing is a
bimetallic temperature valve, which will start to close
at 30°C (86°F) and will fully close at 50°C (122°F).
This allows pre-heated diesel fuel to circulate inside the
fuel filter to prevent waxing in cold operating
conditions.
Fuel Cooler
Two fuel coolers are fitted to the vehicle. One is located
in the vee of the engine block, and has a coolant system
connection to aid heat transfer. The second cooler is
located in the fuel return line and is a fuel to air cooler.
(G421108) Technical Training148
Lesson 2 – PowertrainFuel Charging and Controls 
						

							HP SYSTEM
HPP
The HPP is a three-piston (120 degree apart) radial
plunger pump with a HP displacement of 0.8 cc. As
mentioned, it has the ability to produce a maximum
pressure of 1650 bar. The housing is cast from iron, the
flange is cast from aluminium.
The pump is driven from the camshaft via a toothed
belt. It does not need to be timed to the engine during
belt replacement in service.
The required supply pressure to the HPP is -0.3 bar to
+0.5 bar gauge. The return pressure is -0.3 bar to +0.8
bar gauge.
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							The pump is sized to deliver sufficient fuel to the HP
rails for all engine-operating conditions.
The HPP consists of the following components:
•Internal Transfer Pump (ITP)
•Volume Control Valve (VCV)
•HP pumping elements (3 of)
•Pressure Control Valve (PCV)
The ITP is a 5 vane pump. This conveys fuel to the
VCV.
The VCV is a variable position solenoid valve
electronically controlled by the ECM. The VCV is
located between the ITP and the HP pumping elements.
The VCV determines the amount of fuel that is delivered
to the HP pumping elements. When there is no signal
to the VCV the valve is closed, therefore no fuel
delivery.
The 3 HP pumping elements are connected together in
a fuel ring circuit within the pump. There is a single HP
outlet connection for the HP pipe to the HP diverter rail.
The PCV is a variable position solenoid valve
electronically controlled by the ECM. The PCV is
located between the HP pumping elements and the HP
outlet connection. The PCV regulates the amount of
fuel pressure in the fuel rails and is controlled by the
ECM. When there is no signal to the PCV the valve is
open, therefore no rail pressure can be generated.
High Pressure Fuel Flow
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							LP fuel supplyA
Fuel supply to the HP pumping elementsB
HP outlet connection to the HP diverter railC
LP fuel return (spill)D
LP side of ITP1
ITP pressure relief valve2
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							Screen filter3
VCV4
ITP5
Edge filter (to protect PCV)6
PCV7
N/A8
Eccentric on HPP drive shaft9
Pumping element inlet valve10
Pumping element outlet valve11
HP ring line12
HPP elements (3 of)13
Lubricating valve14
The fuel induced by the ITP (5) is conveyed to the VCV
(4) and the lubricating valve (14).
When the VCV is closed, the ITP pressure relief valve
(2), lying parallel to the transfer pump, opens and
conveys the fuel back to the LP side (1) of the transfer
pump.
The fuel passes through the lubricating valve (14) into
the interior of the HPP and from there to the fuel return
(D). The fuel is used to lubricate the pump.
The VCV (4) determines the quantity of fuel (B) that is
supplied to the pumping elements (13).
The fuel from the HP outlets (11) of the three pumping
elements comes together in a ring line (12) and is
conveyed through the HP outlet of the HPP ©) to the
rails.
The PCV (7) regulates the fuel pressure in the fuel rails.
Reducing rail pressure via the PCV results in fuel from
the rail returning to the LP fuel return (D).
Pump pressure (bar)APump speed (rpm)B
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							The HPP can supply up to 1600 bar fuel pressure
continuously with short excursions to 1650 bar. Pump
speed is 5/6 engine speed. However it is calibrated to
deliver fuel pressure dependant upon engine speed and
load and is always under full control.
When the HPP is rotated, pressure is created when the
VCV is open and the PCV is closed. The VCV and PCV
are variable position to allow variable fuel delivery and
pressure control.
When the ECM actuates the piezo actuators, the rail
pressure drop is off-set by additional fuel being
delivered to the HP rails by the PCV.
Pressure Reduction After Engine Has Stopped
The fuel pressure in the system is reduced within a few
seconds after the engine has stopped as the PCV no
longer has the holding current it requires, and therefore
opens. No residual pressure remains in the system and
the fuel is returned to the fuel return line (D) through
the open PCV. The system is pressureless.
Function of High A Pressure Element
Fuel Induction
During the downward motion of the piston (3), a vacuum
in the pump cylinder is generated, which opens the inlet
valve (1) against the force exerted by the valve spring.
The fuel (A), which is flowing past the VCV, is sucked
in. At the same time the outlet valve (2) is closed due
to the pressure difference between the pump cylinder
and the HP fuel in the ring line.
Fuel Charging and ControlsLesson 2 – Powertrain
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							Fuel DeliveryThe eccentric on the HPP driveshaft (5) presses the
piston (3) upwards. The inlet valve (1) is then closed
through the force exerted by the valve spring and the
pressure being built up in the pump cylinder. The outlet
valve (2) opens when the pressure in the pump cylinder
is greater than the fuel pressure in the ring line (B).
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							Volume Control Valve (VCV)
Piston1
Sleeve2
Compression spring3
Coil4
Armature5
VCV6
The VCV is fixed directly to the HPP.
The VCV regulates the fuel supply (and hence the
quantity of fuel) from the transfer pump to the HPP
elements, depending on the fuel pressure in the rail.
This makes it possible to match the delivery of the HPP
to the requirements of the engine from the low-pressure
side. The quantity of fuel flowing back to the main fuel
supply line is kept to a minimum.
In addition, this adjustment reduces the power
consumption of the HPP, improving the efficiency of
the engine.
NOTE: The fuel volume control valve default is closed
without electrical supply. An open circuit connector
will prevent the engine from running.
NOTE: The VCV cannot be replaced as a separate
component in service.
Fuel Charging and ControlsLesson 2 – Powertrain
155Technical Training (G421108) 
						

							VCV not actuatedA
VCV actuatedB
Fuel supply from the transfer pump1
Piston2
Fuel supply to the HPP3
Coil energised4
Quantity of fuel5
Control current6
VCV at constant engine speed7
VCV Not Actuated (A)
When there is no power supplied, the piston (2) closes
the opening between the two connections (1) and (3)
through the force of the compression spring. The fuel
supply to the HPP is interrupted.
VCV Actuated (B)
The ECM energizes the coil (4) of the valve, according
to the engines requirements. The armature force is
proportional to the control current and counteracts the
compression spring through the moving piston (2).
As a result, the opening between the two connections
(1) and (3) and hence the quantity of fuel (5) supplied
through the connector (3) to the HPP is also proportional
to the control current (6). This means that the greater
the opening cross-section, the greater the quantity of
fuel supplied.
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Lesson 2 – PowertrainFuel Charging and Controls