Mercedes S-class W202

1993-2000 of release

Repair and car operation



Mercedes W202
+ 1.2. The general data
+ 2. Maintenance service
+ 3. Engines
+ 4. Greasing system
+ 5. Cooling system
+ 6. Heating, ventilation
+ 7. Ignition system
- 8. Fuel system
   + 8.1.1. Introduction
   - 8.2. System of injection of petrol engines
      8.2.1.1. A principle of work PMS
      8.2.1.2. A principle of work HFM
      8.2.2. Self-diagnosing of a condition of system of ignition and fuel injection
      8.2.3. Air flowmeter
      8.2.4. A temperature-sensitive element of a cooling liquid
      8.2.5. The gauge of soaked up air
      8.2.6. System of vacuum pipelines
      8.2.7. The fuel distributor with клапанными atomizers
      8.2.8. Klapannye atomizers
      8.2.9. The oxygen gauge (ljambda-probe)
      8.2.10. Diagnostics of malfunctions of system of injection of gasoline
      8.2.11. That it is necessary to know to the owner of the car with инжекторным the engine
      8.2.12. The Turbo-doctor
   + 8.3. System of injection and a food of diesel engines
   + 8.4. System of release of the fulfilled gases
+ 9. Transmission
+ 10. A running gear
+ 11. A steering
+ 12. Brake system
+ 13. A body
+ 14. An electric equipment
+ 14.2. Electroschemes







8.2.1.2. A principle of work HFM
THE GENERAL DATA

Considerable difference in comparison with a PMS-control system of the engine is application of a flowmeter of air with a film heater (HFM) instead of the gauge of pressure of air.

Air flowmeter (В2/5) promotes even more exact dispensing of fuel. A principle of functioning of measurement of the expense of air: the plate of the gauge heated up by means of an electricity (70/1) is cooled by let in air proceeding by.

To maintain a constant temperature of a plate of the gauge, the heating current changes according to density and temperature of let in air. On the basis of fluctuations of a current of heating the actuation device defines weight of let in air and according to it regulates quantity of injected fuel. (70/4 - a protective lattice.)

Klapannye atomizers cope by turns according to an operating procedure of cylinders, thanks to it it is possible to co-ordinate dispensing of fuel with corresponding power setting even more precisely. The professional term of process: consecutive injection.

The system of antidetonation regulation serves for definition and an establishment of the optimum moment of ignition of fuel, even at it more poor quality. In case of malfunction of system of ignition fuel giving to corresponding cylinder stops.

By means of an electrohydraulic executive office there is a displacement of an inlet camshaft in relation to an actuation device asterisk. By means of displacement in a direction of late ignition the smooth course of the engine in an idling mode improves, or at high frequencies of rotation raises capacity. In the bottom and average range of valves filling of cylinders and by that a twisting moment improves.

The 6-cylinder engine: the resonant switching inlet gas pipeline which depending on frequency of rotation of a shaft of the engine changes air route to cylinders is applied to improvement of character of a twisting moment at low frequencies of rotation. For this purpose the air collector behind throttle заслонки is divided into two half by shutter, пневматически put in action: one air stream moves accordingly on 3 cylinders. Extent of an inlet path at low frequencies of rotation thanks to resonant effect provides good filling of the cylinder and, hence, a high twisting moment. At high frequencies of rotation the shutter opens that in a condition completely to use potential of capacity of the engine.