17.2. General information

For simplification of start of the cold engine on diesel engines the system of prestarting heating which consists of candles of an incandescence, the control unit of glow plugs, a control lamp on a combination of devices, the sensor of temperature of cooling liquid and electric wires is installed.

Glow plugs represent a tiny heater, on the one hand which the heating element is located, and on the other hand - contacts. In each combustion chamber about one glow plug is established. Before start of the engine on glow plugs tension moves, and candles quickly get warm, increasing temperature in the combustion chamber. A working part of a glow plug is located at the basis of a fuel nozzle. As a result injecting my fuel passes about a glow plug and heats up therefore fuel combustion process improves. Besides, small particles of fuel, passing about a glow plug, light up that improves fuel ignition process.

Duration of time of giving of tension to glow plugs is regulated by the control unit. On early models the control unit controls air temperature in a motor compartment. On later models the control unit controls temperature of cooling liquid on the basis of information from the sensor which is built in in a head of the block of cylinders. On the basis of information obtained from temperature sensors, the control unit regulates time of giving of tension to spark plugs.

Fire of a control lamp on a combination of devices demonstrates work of spark plugs. Within several seconds of a candle are heated to high temperature, and the control bulb dies away that serves as a signal for start of the engine. If the attempt to start the engine after switching off of a control lamp does not become, the timer will disconnect tension from incandescence candles to avoid a discharge of the accumulator and an overheat of candles of an incandescence. If on later models the control bulb burns after start of the engine, so in system of prestarting heating there is a malfunction.

It should be noted that on later models of a glow plug are disconnected not right after start of the engine, and after a while, allowing the engine to come to a normal operating mode. Period of operation of candles of an incandescence after start of the engine depends on temperature of cooling liquid.

Failure even of one glow plug leads to the complicated start of the engine with interruptions in work and strong vibration.

Obgoraniye and failure of a glow plug often are a consequence of malfunction of fuel nozzles. If there is a burned candle, then simple replacement insufficiently. It is necessary to make the check of nozzles including definition of a form of a torch of dispersion, pressure of operation and tightness. It is important that nozzles had an accurate cut-off of fuel.