1999 LAND ROVER DEFENDER Workshop Manual

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EMISSION CONTROL
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DESCRIPTION AND OPERATION This page is intentionally left blank
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17EMISSION CONTROL
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DESCRIPTION AND OPERATION EGR SYSTEM COMPONENTS - TYPE 1
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EMISSION CONTROL
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DESCRIPTION AND OPERATION 1.EGR Solenoid
2.Vacuum hose (light brown)
3.T-piece
4.Vacuum hose to brake servo
5.Non-return valve
6.Brake servo
7.Inlet manifold
8.Exhaust manifold
9.EGR pipe
10.Vacuum pump/alternator assembly
11.Air intake hose from intercooler
12.EGR valve assembly
13.Vacuum hose to vacuum pump
14.Vacuum hose to EGR valve suction port (blue)
15.To atmosphere
16.In-line filter
17.Vent hose - EGR solenoid to in-line filter (green)
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17EMISSION CONTROL
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DESCRIPTION AND OPERATION EGR SYSTEM COMPONENTS - TYPE 2
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EMISSION CONTROL
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DESCRIPTION AND OPERATION
CAUTION: Inset A shows the Pre-EU3 condition for the EGR pipe. Inset B shows the Pre-EU3
condition filter and venting.
1.ILT valve modulator
2.ILT modulator vacuum hose (brown)
3.EGR valve modulator
4.EGR modulator vacuum hose (brown)
5.Vent hose - EGR modulator to in-line filter (green)
6.Vacuum hose to ILT valve suction port (blue)
7.Vacuum hose to EGR valve suction port (blue)
8.’T’-piece (4-way)
9.Vacuum hose to brake servo
10.Non-return valve
11.Brake servo
12.Inlet manifold
13.Exhaust manifold
14.ILT valve
15.EGR cooler - EU-3 models
16.Vacuum pump/alternator assembly
17.Air intake hose from intercooler
18.EGR valve (incorporating ILT valve) assembly
19.Vacuum hose to vacuum pump
20.Vent hose - ILT valve modulator to in-line filter (green)
21.3-way connector
22.Vent hose to air cleaner
23.ILT modulator harness connector (green)
24.EGR modulator harness connector (black)
25.To atmosphere - Pre-EU3 models
26.In-line filter - Pre-EU3 models
27.EGR pipe - Pre-EU3 models
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17EMISSION CONTROL
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DESCRIPTION AND OPERATION EMISSION CONTROL SYSTEMS
Engine design has evolved in order to minimise the emission of harmful by-products. Emission control systems
fitted to Land Rover vehicles are designed to maintain the emission levels within the legal limits pertaining for the
specified market.
Despite the utilisation of specialised emission control equipment, it is still necessary to ensure that the engine is
correctly maintained and is in good mechanical order, so that it operates at its optimum condition.
In addition to emissions improvements through engine design and the application of electronic engine
management systems, special emission control systems are used to limit the pollutant levels developed under
certain conditions. Two main types of additional emission control system are utilised with the Td5 engine to reduce
levels of harmful emissions released into the atmosphere. These are as follows:
Crankcase emission control - Also known as blow-by gas emissions from the engine crankcase.
Exhaust gas recirculation - To reduce NO
2emissions.
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EMISSION CONTROL
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DESCRIPTION AND OPERATION CRANKCASE EMISSION CONTROL
All internal combustion engines generate oil vapour and smoke in the crankcase as a result of high crankcase
temperatures and piston ring and valve stem blow-by. A closed crankcase ventilation system is used to vent
crankcase gases back to the air induction system and so reduce the emission of hydrocarbons.
Gases from the crankcase are drawn into the inlet manifold to be burnt in the combustion chambers with the fresh
air/fuel mixture. The system provides effective emission control under all engine operating conditions.
Crankcase gases are drawn through the breather port in the top of the camshaft cover and routed through the
breather hose and breather valve on the flexible air intake duct to be drawn into the turbocharger intake for
delivery to the air inlet manifold via the intercooler.
An oil separator plate is included in the camshaft cover which removes the heavy particles of oil before the
crankcase gas leaves via the camshaft cover port. The rocker cover features circular chambers which promote
swirl in the oil mist emanating from the cylinder head and camshaft carrier. As the mist passes through the series
of chambers between the rocker cover and oil separator plate, oil particles are thrown against the separator walls
where they condense and fall back into the cylinder head via two air inlet holes located at each end of the rocker
cover.
The breather valve is a pressure depression limiting valve which progressively closes as engine speed increases,
thereby limiting the depression in the crankcase. The valve is of moulded plastic construction and has a port on
the underside which plugs into a port in the flexible air duct. A port on the side of the breather valve connects to
the camshaft cover port by means of a breather hose which is constructed from a heavy duty braided rubber hose
which is held in place by hose clips. A corrugated plastic sleeve is used to give further protection to the breather
hose. The breather valve is orientation sensitive, and’TOP’is marked on the upper surface to ensure it is
mounted correctly.
It is important that the system is air tight. Hose connections to ports should be checked and the condition of the
breather hose should be periodically inspected to ensure it is in good condition.
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