Audi A4, S4
Since 2000 of release
Repair and car operation
Audi A4, S4
+ Controls and receptions of safe operation
+ Current leaving and service
+ The engine
+ Systems of cooling, heating and the air conditioner
- Power supply systems, release and decrease in toxicity of the fulfilled gases
+ Power supply systems of petrol and diesel engines
+ System of injection of fuel of the petrol engine
- System of injection of fuel of the diesel engine
The general information
Operation in the winter
Checks of system of injection of fuel
+ Systems of release and decrease in toxicity of the fulfilled gases. turbocharger
+ Systems of an electric equipment of the engine
+ Manual box of a gear change
+ Automatic transmission
+ Coupling, power shafts and differential
+ Brake system
+ Suspension bracket and steering
+ Onboard electric equipment
System of injection of fuel of the diesel engine
The general information
The fuel system of the diesel engine copes an electronic control system of the engine. It has following advantages:
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 to 700°С, 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.
Air in the engine is sucked in or arrives from турбокомпрессора and passes through the air filter. turbocharger compresses air which then arrives in интеркулер where it is cooled after heating as a result of compression in турбокомпрессоре. Cooling promotes the best filling of cylinders with forced air that in turn raises a twisting moment and capacity of the engine.
For reduction of a share of harmful substances in the fulfilled gases diesel engines have diesel oxidising каталитический the converter. Simultaneously the system recycling provides essential decrease in the fulfilled gases of the maintenance of oxides of nitrogen. It is reached thanks to giving of the fulfilled gases to air soaked up by the engine that provides decrease in concentration of oxygen in air arriving in cylinders of the engine. It leads to a delay of ignition and to lower temperature of combustion that as a result reduces formation NOx. Process recycling the fulfilled gases should be dosed out precisely however, the soot maintenance otherwise increases in the fulfilled gases. For this purpose the quantity of sucked in air is defined by a measuring instrument that allows the electronic block to operate process recycling.
Fuel injection is carried out directly in the combustion chamber.
In the bottoms of pistons there are the vortical chambers providing a turbulence of combustion arriving in chambers of fuel.
Management of warming up of the cold engine is carried out by the engine management block. At the cold engine the injection moment is displaced by the management block. The engine management block, in turn, operates work of candles накаливания. Candles накаливания are established in each cylinder and join before engine start, work during time проворачивания the engine as a starter and some time after engine start. Candles considerably facilitate start of the cold engine. After ignition inclusion on a control panel the lamp (address to the Head Controls and receptions of safe operation), signalling about inclusion of candles накаливания lights up. As soon as the lamp will go out, you can start the engine. If air temperature very low, candles continue to work still some time after engine start. It reaches stable work of the engine and decrease in harmful impurity in the fulfilled gases.
Owing to high starting qualities of the engine with direct injection in a cold condition preliminary heat is required only at temperature more low-10°S.
Fuel passes through the fuel filter. In the filter fuel separates from water and pollution. Therefore it is important to delete water from fuel and to make timely replacement of a filtering element.
The engine of 2.5 l with direct injectionArrangement of elements of system of injection in a compartment of the diesel engine of 2.5 l
Fuel is soaked up distributive ТНВД from a fuel tank.
ТНВД creates pressure nearby 900 атм. Also injects fuel through multijet atomizers in two steps, according to ignition order. At first preliminary injection of small volume of fuel that creates necessary conditions for the subsequent injection of the basic volume of fuel is made. Such process provides softer and less noisy combustion of fuel just as it occurs at вихрекамерном injection.
ТНВД does not demand service. All mobile parts of the pump are greased with diesel fuel. Drive ТНВД is carried out from a cranked shaft of the engine by a gear belt.
The engine of 1.9 l with direct injection
Arrangement of elements of system of injection in a compartment of the diesel engine of 1.9 l
Here injection occurs by means of system "pump-atomizer" (an illustration more low). Unlike the previous system of injection where fuel is compressed by one ТНВД for all atomizers, system "pump-atomizer" has for each cylinder own ТНВД.
Thus, ТНВД, the operating valve and an atomizer are united in one block.
The block the pump-atomizer
Giving of diesel fuel is carried out by the electric fuel pump located in a tank, and also the mechanical fuel pump submitting fuel to the block the pump-atomizer. Mechanical fuel насосвместе with the vacuum pump it is fixed on a head of cylinders and it is set in motion directly from a camshaft. Four fuel pumps of the block the pump-atomizer are set in motion by the additional cam, located on distributive to a shaft, through the roller lever. The volume of injected fuel is regulated by the block of management of the engine through electromagnetic valves.
Owing to a compression high pressure in the block the pump-atomizer fuel strongly heats up that negatively affects work of the gauge of a stock of fuel in a tank. For fuel cooling in the returnable pipeline there is a special refrigerator.
Before fuel hit in the fuel pump it passes through the fuel filter. There from fuel separate water and pollution. It is necessary to pay attention to importance of service of the fuel filter.