Glow plugs are needed because diesel engines produce the heat needed to ignite the air-fuel mixture by compressing air in the cylinder and combustion chamber. In cold weather, and when the cylinder block, engine oil, and cooling fluid are cold, the heat generated during the first revolutions of the crankshaft is absorbed by the surrounding components, preventing the air-fuel mixture from igniting. The glow plugs are turned on before the engine crankshaft is turned by the starter, warming up the combustion chamber, and remain on for some more time to ensure the ignition of the first charges of the air-fuel mixture. Once the engine is started, there is no need for glow plugs, although in some engines the glow plugs remain on for 5-10 seconds after starting to ensure smooth and efficient operation, and sometimes also to control emissions, since the completeness of combustion of the air-fuel mixture on a cold engine is significantly getting worse. During this period, the power supplied to the glow plugs is greatly reduced in order to prevent the glow ignition phenomenon.
The glow plugs are controlled by the preheating system control unit. Temperature and energy consumption are controlled by the engine management system, providing a wide range of heating according to the required mode. Power is supplied individually to each glow plug. This ensures optimal glow plug warm-up time, minimizing engine start waiting time and maximizing plug life. If a malfunction occurs in the preheating system, the corresponding malfunction code will be transmitted to the driver information center.
A normally functioning system works as follows:
- Switch on the ignition with the engine off and at room temperature.
- The glow plugs turn on and heat up continuously for two seconds and then in pulses for another two seconds.
- The preheating system indicator lamp illuminates for one second when the engine is cold started.
- The preheating system indicator lamp should not light when starting a warm engine.
- If the engine is cranked by the starter during or after the above, the glow plugs should turn on and off after the ignition is returned from cranking, whether the engine is running or not. Starting the engine does not cancel the glow plug cycle.
Glow plug initialization time varies depending on system voltage and temperature. Lowering the temperature makes the glow time of the candle longer.
The engine control unit ensures the operation of the glow plugs after a cold start of the engine. This post-muscle function is initiated after the ignition switch is returned to the «Run» (engine operation) out of position «Start» (crankshaft rotation by starter). This feature helps eliminate white smoke from the exhaust and/or unstable idling.
Visitor comments