BMW 5 series E39

Since 1996-2001 of release

Repair and car operation

The power supply system of the diesel engine

Principle of work of the diesel engine

At work of the diesel engine in its cylinders pure air which is compressed to a high pressure is soaked up. Thus air temperature rises approximately to + 600С, exceeding temperature of ignition of diesel fuel. Fuel is injected into the cylinder with some advancing and ignites. Thus, spark plugs for fuel ignition are not used.

At the cold engine the temperature of compression of air appears insufficient for fuel ignition. The preliminary heating of the engine in this case is required. For this purpose in each cylinder of the engine the electric candle накаливания is established. For improvement of start-up of the cold engine the beginning of giving of fuel is displaced aside earlier injection. After achievement by the engine of working temperature the injection beginning automatically is displaced in the opposite direction. Management of the injection beginning is carried out by block DDE (DDE - system of digital diesel electronics) also, as well as management of quantity of injected fuel and management of pressure of air of pressurisation.

Fuel is sucked in топливоподкачивающим by the pump and moves to the fuel pump of a high pressure (ТНВД) the engine. In ТНВД fuel is compressed to pressure nearby 160 bar and injected in an order similar to an order of ignition in the petrol engine. The quantity of injected fuel is defined by block DDE according to influence on a gas pedal. Position of a pedal of gas is defined by a potentiometer. Fuel injection in cylinders occurs through atomizers. Thanks to presence of the prechamber or the vortical chamber soaked up air receives certain movement that provides its good hashing with injected fuel.

Before fuel receipt in ТНВД it passes the fuel filter where separates from pollution and water. It is necessary to clear and replace the filter periodically.

ТНВД does not demand leaving. Mobile details of the pump are greased with diesel fuel. Drive ТНВД is carried out from a cranked shaft through a chain.

For an engine stop there is an electromagnetic valve at ТНВД. At signal giving on the valve fuel giving to ТНВД stops and the engine stops.

Block DDE reveals available malfunctions in work of the engine and registers them. By means of the special device the malfunctions found out by the block can be считаны from memory and further are eliminated.