Glow plugs are miniature heating elements housed in a metal casing.
At one end of the glow plug there is a probe of the working element, at the other an electrical contact. Each of the swirl chambers/mouth of the cylinder is equipped with an individual glow plug. The working element of the plug is located coaxially with the jet of injected fuel. When power is supplied to the plug, the injected fuel is heated, reaching the optimum combustion temperature before entering the cylinder.
The pre-glow period duration is determined by the system control unit, which monitors engine temperature from the CTS readings and adjusts the glow plug power supply timing according to specific conditions.
The control lamp built into the instrument panel informs the driver about the system operation. When the mixture temperature required for successful engine starting is reached, the lamp switches off, but power continues to be supplied to the spark plugs for some time. If no attempt to start occurs within the specified period, the spark plugs are switched off to prevent the battery from being discharged and the working heating elements from burning out. On some models, if the control unit detects a malfunction of the preheating system, the control lamp continues to light even when the engine is running.
Strictly speaking, the pre-heating system is activated by turning the ignition key to position II. However, Felicia models are additionally equipped with a pre-heating system, which is activated when the driver's door is opened and then closed. Naturally, the system is activated once for each engine start. If no attempt is made to start the engine within a certain time after opening and closing the driver's door, the system will not be reactivated when the door is opened.
Glow plugs continue to operate for up to 3 minutes after the engine is started, which improves the efficiency of mixture ignition, reduces noise levels, stabilizes idle speed and reduces exhaust gas toxicity.