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The power supply system of diesel engines

Overview

In operation of the diesel engine in its cylinders is sucked outside air, which is compressed to a high pressure. The temperature of the air as a result of adiabatic heating is raised to the level of 700-900 ?� C, flash point greater than diesel fuel. Fuel is injected into the cylinder with some advancing and ignites. Thus, the need for a spark plug is eliminated.

To reduce the content in the exhaust gases of toxic components of diesel models are equipped with special oxidation catalytic converter. Simultaneously recirculation system (EGR), by mixing metered to the suction air into the engine of a small amount of exhaust gas, and - as a consequence - reducing the concentration of oxygen in the fuel mixture, provides a significant reduction in the content of the products of combustion nitrogen oxides _(NO X). Due to the operation of the EGR system is a reduction of the ignition delay and lowering the combustion temperature, which ultimately leads to reduced formation of _NO X. An indispensable condition for organizations EGR dosing accuracy is mixing as otherwise increasing content in the exhaust gas particulate carbon (soot). The amount of intake air into the engine is determined by a special measuring instrument issued by that information allows the electronic control module to monitor the process of recycling.

Fuel injection is made directly into the combustion chambers of cylinders (CDI).

The functioning of the engine controls the electronic system, the structure and principle of operation is similar to the engine management system, used on petrol models. The basis of the generated control module commands go to the data coming from the whole set of information sensors to continuously monitor the operating parameters of the engine and the transmission line.

Information about the position of the crankshaft and the engine speed is supplied to the control unit from the crankshaft position sensor (CKP). Inductive sensor head is located in front of the flywheel and constantly scans specific reference mark on the surface of the latter. With the passage of the mark past the sensor of the measuring head sensor generates a signal pulse output from the control module. Label uniformly applied to the surface of the flywheel, except for a single pass, corresponding to position 90 ?� before TDC of the piston of the first cylinder. At the time of passage of the point of the flywheel signal pulse is issued to the control module, which allows the latter to determine the time of TDC. Along the length of the pause / pulse ratio module receives information on engine speed.

Information on the quantity and temperature of the air entering the engine comes from the absolute pressure sensor in the intake manifold (MAP) and Intake Air Temperature (IAT). The MAP sensor is connected to a vacuum hose from the intake manifold and measure the depth of the depression inside the latter. To control the intake air temperature sensor uses two IAT, one of which is installed in front of the turbocharger, and the other - behind the intercooler (intercooler). Removable sensor readings are used by the control module in the calculation of the precise amount of fuel to be injected into the combustion chamber of the engine.

Traditional coolant temperature sensor is replaced by the temperature sensor head unit supplying the control module information, used when quality adjustment of air-fuel mixture and the calculation of the moments of injection. In addition, the recorded sensor data is used to manage the operation of preheating a cold engine.

The gauge-switch of stoplights / brake pedal position informs the control unit about the current position of the foot brake. Upon receipt of the signals from these sensors control system instantly translates the engine to idle and maintains it up to the time of receipt of the signal from the accelerator pedal position sensor.

Fuel is organized according to the scheme of direct injection. The piston head includes vortex chamber, providing twisting injected into the combustion chambers of cylinders of fuel. In order to optimize the combustion process of nozzles opening is made in two steps (for each of the nozzles positioned inside two springs). Upon opening nozzle valve working small portion of the fuel strikes the internal components of the latter, providing for lubrication, and then returned to the fuel tank.

Monitoring is also carried out pre-heating the engine control module, which is a cold engine provides a certain offset injection timing. Furthermore, the control unit controls the process of operation of the glow plug. Glow plugs are screwed into each cylinder is activated before the engine start, and remain in the hot state during the time of cranking the starter, and a while after engine start. Use of glow plugs can largely facilitate engine starting in cold weather. On activation of the driver warning special candles mounted in the instrument cluster indicator lamp (see chap. Controls and operation receptions) - as soon as the light goes out, you are ready to start the engine. In very cold weather, candles continue to operate for a while after starting, maintaining the stability of the engine speed and providing a reduction of toxic components in the combustion products.

The design of modern diesel engines has high efficiency of startup, resulting in the need to use glow plugs occurs only at temperatures below - 10 ?� C.

Inflate the preliminary fuel pump fuel passes through the fuel filter, where it made removal of impurities moisture and other contaminants, try to relate faithfully to perform maintenance procedures, timely replacement of the filter element.