Mercedes C-Class

W203 since 2000 of release

Repair and operation of the car

+ Mercedes-Benz cars of class C (W-203)
+ Operation manual
+ Routine maintenance
+ Engine
+ Cooling system and heating
+ Power supply system and release
- Engine electric equipment
   + System of ignition and engine management
   - System of preheat of the diesel engine
      Check of candles of an incandescence
      Removal and installation of candles of an incandescence
   + Diagnostics of systems of electronic control and diagnostic equipment
   + Systems of a charge and start
+ Manual transmission
+ Automatic transmission
+ Coupling and power shafts
+ Brake system
+ Suspension bracket and steering
+ Body
+ Onboard electric equipment

System of preheat of the diesel engine

General information

On the cold diesel engine, at compression of air in cylinders, temperature, necessary for fuel spontaneous ignition, is not reached. For this reason preheat is required.

For this purpose in each combustion chamber the glow plug is established. The glow plug consists of the case with a heating core, vpressovanny in it. The heating core in turn consists of a heating spiral and an adjusting spiral. After giving of tension the heating spiral in a core heats up within several seconds to temperature + 850 °C. At the same time the current passing on a candle reaches 30A. At increase in heating spiral resistance increases that limits current to 15 - 25 And. When the control lamp of preheat on the dashboard dies away, the engine can be started.

The preheat time necessary for start of the engine makes no more than 10 pages. Time is regulated by the relay of preheat and the control unit of the engine which via the sensor of temperature of cooling liquid obtains information on the current temperature of the engine. The control unit of the engine on the basis of the obtained information makes the decision on duration of inclusion of candles of an incandescence and necessary current of heating.

On the diesel engine with direct injection preheat is required only at a temperature below 0 °C.