octane LAND ROVER DISCOVERY 2002 Workshop Manual

INTRODUCTION
01-4
HRW Heated Rear Window
HSLA High Strength Low Alloy
ht/HT High tension
IACV Idle Air Control Valve
IAT Intake Air Temperature
ICE In-Car Entertainment
i.dia. Internal diameter
IDM Intelligent Driver Module
IF Intermediate Frequency
in
3Cubic inch
ILT Inlet Throttle
IPW Injector Pulse Width
ISO International Organisation for
Standardisation
ITS Inflatable Tubular Structure
k Thousand
kg Kilogramme
kg/h Kilogrammes per hour
km Kilometre
km/h Kilometres per hour
kPa KiloPascal
KS Knock Sensor
lLitre
lb(s) Pounds
lbf Pounds force
lbf.in Pounds force inches
lbf/in
2Pounds per square inch
lbf.ft Pounds force feet
λLambda
lc Low compression
LCD Liquid Crystal Display
LED Light Emitting Diode
LEV Low Emission Vehicle
LH Left-Hand
LHD Left-Hand Drive
LSM Light Switch Module
LVS Liquid Vapour Separator
mMetre
µMicro
MAF Mass Air Flow
MAP Manifold Absolute Pressure
MET Mechanical, Electrical and Trim
MFU Multi-Function Unit
MFL Multi-Function Logic
max. Maximum
MEMS Modular Engine Management
System
MIG Metal/Inert Gas
MIL Malfunction Indicator Lamp
MPa MegaPascal
MOSFET Metal Oxide Semiconductor Field
Effect Transistor
min. Minimum
- Minus (tolerance)
' Minute (angle)
mm Millimetre
mph Miles per hour MPi Multi-Point injection
MV Motorised Valve
MY Model Year
NAS North American Specification
(-) Negative (electrical)
Nm Newton metre
No. Number
NO
2Nitrogen Dioxide
NO
xOxides of Nitrogen
NTC Negative Temperature
Coefficient
NRV Non Return Valve
OBD On Board Diagnostics
OBM On Board Monitoring
o.dia. Outside diameter
OAT Organic Acid Technology
ORM Off-road Mode
ΩOhm
PAS Power Assisted Steering
PCB Printed Circuit Board
PCV Positive Crankcase Ventilation
PDC Parking Distance Control
PDOP Position Dilation Of Precision
PI Programme Information
PPS Pulse Per Second
PS Programme Service
psi Pounds per square inch
pts. Pints
% Percentage
+ Plus (tolerance) or Positive
(electrical)
±Plus or minus (tolerance)
PTC Positive Temperature Coefficient
PTFE Polytetrafluorethylene
PVC Polyvinyl chloride
PWM Pulse Width Modulation
RDS Radio Data Service
rRadius
:Ratio
ref Reference
REG Regionalisation
RES Rover Engineering Standards
rev/min Revolutions per minute
RF Radio Frequency
RGB Red / Green / Blue
RH Right-Hand
RHD Right-Hand Drive
ROM Read Only Memory
RON Research Octane Number
ROV Roll Over Valve
ROW Rest Of World
SAE Society of Automotive Engineers
SAI Secondary Air Injection
" Second (angle)
SLABS Self Levelling and Anti-Lock
Brake System
SLS Self Levelling Suspension
SOHC Single Overhead Camshaft

EMISSION CONTROL - V8
17-2-10 DESCRIPTION AND OPERATION
A spiral oil separator is located in the stub pipe to the ventilation hose on the right hand cylinder head rocker cover,
where oil is separated and returned to the cylinder head. The rubber ventilation hose from the right hand rocker cover
is routed to a port on the right hand side of the inlet manifold plenum chamber where the returned gases mix with the
fresh inlet air passing through the throttle butterfly valve. The stub pipe on the left hand rocker cover does not contain
an oil separator, and the ventilation hose is routed to the throttle body housing at the air inlet side of the butterfly valve.
The ventilation hoses are attached to the stub pipe by metal band clamps.
Exhaust emission control system
The fuel injection system provides accurately metered quantities of fuel to the combustion chambers to ensure the
most efficient air to fuel ratio under all operating conditions. A further improvement to combustion is made by
measuring the oxygen content of the exhaust gases to enable the quantity of fuel injected to be varied in accordance
with the prevailing engine operation and ambient conditions; any unsatisfactory composition of the exhaust gas is
then corrected by adjustments made to the fuelling by the ECM.
The main components of the exhaust emission system are two catalytic converters which are an integral part of the
front exhaust pipe assembly. The catalytic converters are included in the system to reduce the emission to
atmosphere of carbon monoxide (CO), oxides of nitrogen (NO
x) and hydrocarbons (HC). The active constituents of
the catalytic converters are platinum (Pt), palladium (PD) and rhodium (Rh). Catalytic converters for NAS low
emission vehicles (LEVs) from 2000MY have active constituents of palladium and rhodium only. The correct
functioning of the converters is dependent upon close control of the oxygen concentration in the exhaust gas entering
the catalyst.
The two catalytic converters are shaped differently to allow sufficient clearance between the body and transmission,
but they remain functionally identical since they have the same volume and use the same active constituents.
The basic control loop comprises the engine (controlled system), the heated oxygen sensors (measuring elements),
the engine management ECM (control) and the injectors and ignition (actuators). Other factors also influence the
calculations of the ECM, such as air flow, air intake temperature and throttle position. Additionally, special driving
conditions are compensated for, such as starting, acceleration, deceleration, overrun and full load.
The reliability of the ignition system is critical for efficient catalytic converter operation, since misfiring will lead to
irreparable damage of the catalytic converter due to the overheating that occurs when unburned combustion gases
are burnt inside it.
CAUTION: If the engine is misfiring, it should be shut down immediately and the cause rectified. Failure to do
so will result in irreparable damage to the catalytic converter.
CAUTION: Ensure the exhaust system is free from leaks. Exhaust gas leaks upstream of the catalytic
converter could cause internal damage to the catalytic converter.
CAUTION: Serious damage to the engine may occur if a lower octane number fuel than recommended is used.
Serious damage to the catalytic converter and oxygen sensors will occur if leaded fuel is used.
Air : fuel ratio
The theoretical ideal air:fuel ratio to ensure complete combustion and minimise emissions in a spark-ignition engine
is 14.7:1 and is referred to as the stoichiometric ratio.
The excess air factor is denoted by the Lambda symbol
λ, and is used to indicate how far the air:fuel mixture ratio
deviates from the theoretical optimum during any particular operating condition.
lWhen
λ = 1, the air to fuel ratio corresponds to the theoretical optimum of 14.7:1 and is the desired condition for
minimising emissions.
lWhen
λ > 1, (i.e. λ = 1.05 to λ = 1.3) there is excess air available (lean mixture) and lower fuel consumption can
be attained at the cost of reduced performance. For mixtures above
λ = 1.3, the mixture ceases to be ignitable.
lWhen
λ < 1, (i.e. λ = 0.85 to λ = 0.95) there is an air deficiency (rich mixture) and maximum output is available,
but fuel economy is impaired.
The engine management system used with V8 engines operates in a narrower control range about the stoichiometric
ideal between
λ = 0.97 to 1.03 using closed-loop control techniques. When the engine is warmed up and operating
under normal conditions, it is essential to maintain
λ close to the ideal (λ = 1) to ensure the effective treatment of
exhaust gases by the three-way catalytic converters installed in the downpipes from each exhaust manifold.

EMISSION CONTROL - V8
17-2-12 DESCRIPTION AND OPERATION
The catalytic converter's housings are fabricated from stainless steel and are fully welded at all joints. Each catalytic
converter contains two elements comprising of an extruded ceramic substrate which is formed into a honeycomb of
small cells with a density of 62 cells / cm
2. The ceramic element is coated with a special surface treatment called
'washcoat' which increases the surface area of the catalyst element by approximately 7000 times. A coating is applied
to the washcoat which contains the precious elements Platinum, Palladium and Rhodium in the following relative
concentrations: 1 Pt : 21.6 PD : 1 Rh
Catalytic converters for NAS low emission vehicles (LEVs) from 2000MY have active constituents of
palladium and rhodium only. The active constituents are 14PD: 1Rh and the palladium coating is used to
oxidise the carbon monoxide and hydrocarbons in the exhaust gas.
The metallic coating of platinum and palladium oxidize the carbon monoxide and hydrocarbons and convert them into
water (H
2O) and carbon dioxide (CO2). The coating of rhodium removes the oxygen from nitrogen oxide (NOx) and
converts it into nitrogen (N
2).
CAUTION: Catalytic converters contain ceramic material, which is very fragile. Avoid heavy impacts on the
converter casing.
Downstream of the catalytic converters, the exhaust front pipes merge into a single pipe terminating at a flange joint
which connects to the exhaust intermediate pipe.
WARNING: To prevent personal injury from a hot exhaust system, do not attempt to disconnect any
components until the exhaust system has cooled down.
CAUTION: Serious damage to the catalytic converter will occur if leaded fuel is used. The fuel tank filler neck
is designed to accommodate only unleaded fuel pump nozzles.
CAUTION: Serious damage to the engine may occur if a lower octane number fuel than recommended is used.
Serious damage to the catalytic converter will occur if leaded fuel is used.
Heated oxygen sensor
1Connection cable
2Disc spring
3Ceramic support tube
4Protective sleeve
5Clamp connection for heating element
6Heating element
7Contact element8Sensor housing
9Active sensor ceramic
10Protective tube
11Post-catalytic converter sensor (NAS spec.
only)
12Pre-catalytic converter sensor