Range Rover. Manual — part 26

BMW DIESEL

5

DESCRIPTION AND OPERATION

Fuel injectors

Fuel is delivered to each cylinder through fuel injector
nozzles. An injector is screwed into a pre-combustion
chamber (swirl chamber) at each cylinder position.

The precombustion chambers are also fitted with glow
plugs. Each injector comprises a nozzle holder and
contains a spring-loaded needle valve; the nozzle
holder of cylinder No 4 incorporates a sender which
senses the time of fuel ejection by recognising needle
movement. This information is utilised by the DDE
system -

See ENGINE MANAGEMENT, Description.

1. Fuel injector
2. Glow plug
3. Pre-combustion chamber
4. Piston crown, V-patterned groove

Air intake

Fresh air is drawn in through an air cleaner assembly
secured to the left hand inner wing of the vehicle. The
air cleaner assembly comprises a housing which
contains a paper filter element. The rectangular,
two-part housing is constructed from moulded plastic
and incorporates an air inlet and an air outlet.

The air cleaner delivers filtered air to the turbocharger.

Forced aspiration system

Forced aspiration is by an exhaust driven
turbocharger. Compressed air, from the turbocharger,
passes through an intercooler to the charge air
collector mounted on the cylinder head.

Turbocharger

The turbocharger consists of a compressor housing
and a turbine housing bolted to the exhaust manifold.
The compressor housing has an ambient air inlet and
a compressed air outlet. The turbine housing has an
exhaust gas inlet and an exhaust gas outlet. Both
compressor and turbine housings are bolted to a
central bearing housing. The bearing housing contains
two pressure lubricated bearings which provide
support for the rotor shaft. An exhaust-gas driven
turbine mounted at one end of the rotor shaft, drives a
centrifugal compressor mounted at the other.

To regulate charge air pressure, a by-pass plate is
installed on the exhaust side of the turbocharger. The
by-pass plate is connected to a pneumatic pressure
actuator.

1. Charge air outlet
2. Pressurised oil from engine
3. Turbine housing
4. Turbine
5. Exhaust gas outlet
6. Exhaust gas inlet
7. Bearing housing
8. Rotor shaft
9. Compressor housing

10. Compressor
11. Air intake

12

ENGINE

NEW RANGE ROVER

6

DESCRIPTION AND OPERATION

Intercooler

To lower the temperature of the charge air, and
therefore increase its density, an intercooler is fitted
between the turbocharger and the charge air collector.

Charge air collector

The charge air collector is bolted to the cylinder head
and consists of a manifold having a single inlet and six
individual outlets, one to each cylinder. Intake charge
air pressure and charge air temperature sensors
mounted on the collector are linked to the control unit
of the DDE system. The air temperature sensor has a
black connector and is fitted at the front of the air
collector. The pressure sensor is a small, black plastic
sensor mounted on the fuel filter bracket. It is
connected to the air collector through a tube.

Operation

When the engine is running, exhaust gas impinges on
the turbine vanes of the turbocharger causing the
turbine to rotate. The rotor shaft transmits drive from
the turbine to the inlet centrifugal compressor. Air is
drawn into the compressor from the air cleaner and
compressed air is discharged to the charge air
collector via the intercooler.

Charge air pressure is regulated by operation of the
by-pass plate.

1. By-pass plate actuator
2. Charge air pressure sensor
3. Intake air (charge air) temperature sensor
4. DDE system control unit

BMW DIESEL

7

DESCRIPTION AND OPERATION

Lubrication system

The lubrication system comprises the sump, pump, oil
filter and oil ducts.

Sump

This is a one-piece, rigid, aluminium, die-cast unit
bolted to underside of the crankcase. An oil deflector
plate is attached to the crankcase reinforcing shell
above the sump. The sump incorporates a drain plug
and a dip-stick guide pipe.

Oil pump

An internal gear-type pump is mounted on the front
end of the crankshaft. It is directly driven by the
crankshaft. The pump consists of a body which
houses a driven rotor and a stator. Pump pressure is
regulated by a piston operated pressure relief valve
housed within the body of the pump.

1. Camshaft bearing
2. Camshaft bearings
3. Oil duct

4. Main oil duct
5. Big end bearing
6. Main crankshaft bearing

12

ENGINE

NEW RANGE ROVER

8

DESCRIPTION AND OPERATION

1. Camshaft timing chain drive
2. Upper tension rail
3. Chain adjuster
4. Injection timing
5. Lower tension rail
6. Oil return

Oil filter

The oil filter is vertically-mounted below the charge air
collector. It consists of a filter element contained
within a housing which is screwed to a filter head. A
filter by-pass valve is installed in the housing, while
the filter head holds a thermostat. The thermostat
promotes quick warm up of the engine by preventing
oil circulating through the oil cooler when the oil
temperature is low. The thermostat operates at 80

°

C.

Oil ducts

Oil circulates around the engine, and is delivered to
the turbocharger bearings, through ducts and oilways.
A longitudinal main oil duct allows oil to be delivered
to the crankshaft bearings. Vertical ducts from the
main duct allow oil to the piston cooling jets and to the
camshaft bearings.

Operation

Refer to the lubrication system circuit diagrams for
lubrication system operating details.

Auxiliary driven assemblies

The auxiliary driven assemblies consist of the
following:

Water pump
Power steering pump
Alternator

The water pump, alternator and power steering pump
are driven from the crankshaft by means of a
decoupled pulley and a 5-rib, automatically tensioned,
V-belt.