Engine preheating valve (VW Golf 2)

After starting the engine, during its warm-up, the engine requires a richer mixture to compensate for the lack of fuel condensing on the cold walls of the drive manifold and cylinders. More fuel is also required to compensate for the loss of power caused by increased friction and higher oil density in a cold engine. During engine warm-up, the mixture is enriched by the engine warm-up valve 20. This is a pressure regulator that reduces the pressure acting on the fuel distributor control piston during starting. This reduced pressure causes the air flow meter plate to rise in position. This opens up a longer cut that measures the fuel, and the mixture is enriched.

The valve is controlled by a bimetallic strap, which is heated by an electric heater. When the engine is cold, the bimetallic strap (nose) presses on the feed valve spring to reduce the pressure on the diaphragm and increase the cross-section of the flow. This increase in cross-section results in a decrease in the pressure acting on the control piston.

Figure 3.51. K-Jetronic injection system diagram
1 - differential measuring valve; 2 - air flow meter; 3 - fuel distributor; 4 - mixture composition adjustment bolt; 5 - fuel tank; 6 - fuel pump; 7 - pressure accumulator; 8 - fuel filter; 9 - pressure regulator; 11 - nozzle; 12 - idle speed adjusting bolt; 13 - battery; 14 - ignition switch; 15 - fuel pump shut-off switch; 16 - ignition distributor; 17 - cold start valve; 18 - Thermal time switch; 19 - additional air valve; 20 - engine heating valve.

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The text has been checked: Semenova Anna