The glow plug preheating system is designed to achieve the required ignition temperature of the fuel mixture in the cylinder at the time of a cold start. In addition, with an economical supply of fuel to the cylinders, it is required to increase the reliability of the ignition of the injected fuel. For this, glow plugs are used, which, due to the combustion of fuel, remain in a heated state.
The combustion chamber is preheated by glow plugs fed from the output stage of the preheating system. The duration of preheating depends on the temperature of the coolant. When the key is turned to position 2, the CDI control unit (N3/9) issues a command to activate the preheat output stage (A1e13) and turning on the preheating warning light (Ale 13), located on the instrument cluster. The duration of preheating is calculated by the engine control unit.
Preheat indicator light (A1e13) goes out at the end of the preheating phase
The information received by the CDI ECU is described in the description of the fuel start mode (see above).
The CDI control unit activates the output stage (N14/2), which supplies power to the glow plugs (R9/1-R9/4).
VN 9.005 Dependence of the preheating time on the coolant temperature t. Heating time, s T Coolant temperature in degrees Celsius.