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Land Rover Defender 1999 2002my Workshop Supplement Body Repair 3rd Edition Rover Manual
Land Rover Defender 1999 2002my Workshop Supplement Body Repair 3rd Edition Rover Manual
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EMISSION CONTROL 1 DESCRIPTION AND OPERATION This page is intentionally left blank
17EMISSION CONTROL 2 DESCRIPTION AND OPERATION EGR SYSTEM COMPONENTS - TYPE 1
EMISSION CONTROL 3 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)
17EMISSION CONTROL 4 DESCRIPTION AND OPERATION EGR SYSTEM COMPONENTS - TYPE 2
EMISSION CONTROL 5 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
17EMISSION CONTROL 6 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.
EMISSION CONTROL 7 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.
17EMISSION CONTROL 8 DESCRIPTION AND OPERATION EXHAUST GAS RECIRCULATION The exhaust gas recirculation (EGR) valve permits a controlled amount of exhaust gas to combine with the fresh air entering the engine. The exhaust gas reduces the combustion temperature by delaying the fuel burning rate, which assists in reducing the quantity of oxides of nitrogen. On EU3 models, an EGR cooler is employed to further reduce the combustion temperature. By passing the exhaust gas through a bundle of pipes flooded by coolant, the density of the exhaust gas going into the engine is increased. This process further reduces the amount of NO 2in the exhaust. Recirculation of too much exhaust gas can result in higher emissions of soot, HC and CO due to insufficient air. The recirculated exhaust gas must be limited so that there is sufficient oxygen available for combustion of the injected fuel in the combustion chamber. To do this the ECM is used to control the precise quantity of exhaust gas to be recirculated in accordance with the prevailing operating conditions. Influencing factors include: The mass of air flow detected by the MAF sensor. The ambient air temperature detected by the AAP sensor. This is used to initiate adjustments to reduce the amount of smoke produced at high altitudes. The mass of air flow detected by the MAF sensor. The ambient air temperature detected by the AAP sensor. This is used to initiate adjustments to reduce the amount of smoke produced at high altitudes. Other factors which are taken into consideration by the engine management system for determining the optimum operating condition include: Manifold inlet air temperature Coolant temperature Engine speed Fuel delivered The main components of the EGR system are as follows.
EMISSION CONTROL 9 DESCRIPTION AND OPERATION EGR MODULATOR 1.Port to vacuum source (white band) 2.Port to EGR valve (blue band)3.Port to atmosphere via in-line filter (green band) 4.Harness connector The EGR modulator is located on a plate fixed to the inner RH front wing. The modulator is attached to the plate by two studs, each with two nuts which secure the assembly to a rubber mounting, which helps reduce noise. The modulator must be mounted vertically with the two vacuum ports uppermost. Modulator operation is controlled by a signal from the ECM which determines the required amount of EGR needed in response to inputs relating to air flow, engine operation, and ambient conditions. The modulator has a two pin connector at its base to connect it to the ECM via the engine harness. The modulator features three ports: The top port is identified by a white band and connects to a T-piece in the vacuum line via a small bore light brown plastic hose. The two other ports on the T-piece connect to the vacuum line hoses of black vinyl tubing between the vacuum pump and the brake servo assembly attached to the bulkhead. The vacuum pump end of the tubing terminates in a rubber elbow, which gives a vacuum tight seal on the suction port of the vacuum pump. The brake servo end of the tubing terminates with a non-return valve in a plastic housing which plugs into the front face of the brake servo housing. The middle port is identified by a blue band, and connects to the suction port on the EGR valve through a small bore blue plastic hose. The lower port is identified by a green band and connects to atmosphere through an in-line filter via a small bore green plastic hose. The blue and brown vacuum hoses are protected by corrugated plastic sheaths. The ends of the hoses are fitted with rubber boots to ensure vacuum tight seals at the component ports.