W203 since 2000 of release
Repair and car operation
+ Mercedes-Benz Cars of a class C (W-203)
+ Operation manual
+ Routine maintenance
+ cooling and heating Systems
- Power supply system and release
+ Power supply system of the petrol and diesel engine
+ System of injection of fuel of the petrol engine
- System of injection of fuel of the diesel engine. Turbokompressor
Removal and installation of nozzles
Air removal from a contour of low pressure of fuel
Checks of system of injection of fuel
+ Systems of release and decrease in toxicity of the fulfilled gases. Turbokompressor
+ engine Electric equipment
+ Manual transmission
+ Automatic transmission
+ Coupling and power shafts
+ Brake system
+ Suspension bracket and steering
+ Onboard electric equipment
System of injection of fuel of the diesel engine. Turbokompressor
System of production of the fulfilled gases - general informationElements of system of injection of fuel of the diesel engine
Function chart of management of fuel injection from the general toplivoraspredelitelny highway of Common Rail (on an engine 611 example)
Arrangement of elements of a control system of Common Rail injection
Arrangement of elements of a control system of Common Rail injection
TNVD, toplivopodkachivayushchy pump, fuel filter and cooler of fuel (1 of 2)
TNVD, toplivopodkachivayushchy pump, fuel filter and cooler of fuel (2 of 2)
Vacuum lines. Engine 611.692
The fuel system of the diesel engine copes an electronic control system of the engine. It has the following advantages:
· Self-diagnostics of a control system by the engine allows to make fast troubleshooting.
· Exact dispensing of amount of injected fuel provides reduction of the content of harmful substances in the fulfilled gases and low fuel consumption.
· Regulation of turns of idling and restriction of turns is made automatically.
At operation of the diesel engine in its cylinders clean 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 ignition of fuel are not used.
Fuel moves the toplivopodkachivayushchy pump under the pressure of 3.5 atm. to the fuel pump of a high pressure (TNVD). In TNVD already on low turns constant pressure of compression over 1300 atm is created.
From TNVD there is the general fuel distributive highway (Common Rail) to separate cylinders. The general highway serves as the accumulator of pressure and distributes fuel with constant pressure on nozzles. The amount of injected fuel is dosed out with necessary accuracy the control unit the engine by means of electromagnetic nozzles. If the control unit microprocessor the engine closes, for example, electromagnetic valves, injection of fuel stops. Differently creation of pressure and injection of fuel occur independently from each other. Advantage of it is that injection can optimum occur, depending on requirement and composition of the fulfilled gases, but irrespective of number of turns of the engine.
For optimization of combustion of fuel multijet nozzles open in two steps. At first preliminary injection of a small amount of fuel that creates favorable conditions for conditions of ignition of the main amount of injected fuel is made. As a result it leads to soft and silent combustion of a fuel mix. When opening nozzle the small part of fuel gets on internal components of a nozzle, greasing them, and comes back to a fuel tank.
Before intake of fuel in the toplivopodkachivayushchy pump and TNVD it passes cleaning in the fuel filter from pollution and water. Therefore is important to make regular replacement of the filter within carrying out maintenance.
Toplivopodkachivayushchy the pump and TNVD do not demand service. All mobile parts of pumps are greased with diesel fuel.
Air in the engine is sucked in or arrives from a turbokompressor and passes through the air filter. Turbokompressor compresses air which then arrives in an interkuler where it is cooled after heating as a result of compression in a turbokompressor. Cooling promotes the best filling of cylinders with forced air that in turn raises a torque and engine capacity.
For reduction of a share of harmful substances in the fulfilled gases diesel engines have the diesel oxidizing catalytic converter. At the same time the system of a retsirkulyatsiya provides essential decrease in the fulfilled gases the content of oxides of nitrogen. It is reached thanks to supply of the fulfilled gases to air soaked up by the engine that provides decrease in concentration of oxygen in the 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 of NOx. Process of a retsirkulyatsiya of the fulfilled gases should be dosed out precisely however, the maintenance of a soot otherwise increases in the fulfilled gases. For this purpose the amount of sucked-in air is defined by a measuring instrument that allows the electronic device to operate retsirkulyatsiya process.
Injection of fuel is carried out directly in the combustion chamber.
The engine copes the electronic system similar to a control system of petrol engines. The system operates operation of the engine, analyzing information arriving from a large number of sensors.
Information on position of the crankshaft and speed of rotation of the engine arrives in the control unit from the sensor of position of the crankshaft. The inductive head of the sensor is located opposite to a flywheel and constantly scans the special labels put on its surface. When passing label by a sensor head it sends an impulse to the control unit. Labels are evenly put on a flywheel surface, but one label is passed. It should settle down in 90 ° to VMT of the first cylinder. At the moment of passing by a flywheel of this point the sensor does not send an impulse to the control unit. The block distinguishes this pause and precisely defines VMT moment. Duration of this pause is used for determination of speed of rotation of the engine.
Information on quantity and temperature of air arriving in the engine arrives from the sensor of absolute pressure in the inlet pipeline and air temperature sensors. The sensor of absolute pressure is connected to the pipeline a vacuum hose and measures pressure in it. Two sensors of air temperature are established. One is established before a turbokompressor, and another — after an interkuler. The temperature and pressure of air are used for calculation of exact amount of fuel which is necessary to fall to nozzles.
The sensor of temperature of cooling liquid takes temperature and sends received information to the control unit. Analyzing this information, the control unit corrects structure and the moment of injection of a fuel mix, and also operates system of warming up of the cold engine.
The switch of stoplights and the sensor of a pedal of a brake informs the control unit on the current provision of a pedal of a brake. When receiving signals from these sensors the control system instantly transfers the engine to idling until will receive a signal from the sensor of provision of a pedal of an accelerator.
The cable of an accelerator is absent. Instead of it on the sensor of provision of a pedal of an accelerator is established. The sensor constantly informs the control unit on the provision of a pedal which, in turn, precisely counts injection parameters. Single turns also are regulated by the control unit and cannot be adjusted manually. Analyzing information arriving from various sensors, the control unit counts size of turns of idling, correcting them depending on load of the engine and its temperature.
The system of injection of fuel is system of direct injection. 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 control unit the engine. At the cold engine the moment of injection is displaced by the control unit. The control unit the engine, in turn, operates work of candles of an incandescence. Glow plugs are established in each cylinder and join before engine start, I work during an engine provorachivaniye with 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 Head the Operation manual), signaling about inclusion of candles of an incandescence 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 operation 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 below - 10°С.
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.
Operation in the winter
At decrease in temperature of external air fluidity of diesel fuel owing to paraffin loss decreases. Diesel fuel on the fluidity becomes similar to honey and can hammer the filter. For this reason the additives increasing fluidity of fuel and providing possibility of start of the engine at temperature of external air to in the winter can be entered into diesel fuel – 22°С.
To exclude a zabivaniye of the fuel filter at low external temperature, fuel goes to the heat exchanger.