Diesel engine preheating device (Mondeo 3)

According to practical experience, diesel engines have a hard time starting only at the first stage of a cold start. Direct injection engines, such as those in the Mondeo, start up even in winter quite "politely" at our latitudes, but they work hard in severe frost, and their first signs of life may not appear entirely without a preheating device.

For this purpose, powerful glow plugs heat the compressed air in the cylinders during the cold engine start-up period, thereby accelerating the ignition process. The glow plugs are located on the side of the cylinder head and, like the preheating indicator lamp on the instrument panel, are monitored by the engine control unit (ECM). To determine the warm-up duration, the ECM receives a temperature signal from the cylinder head temperature sensor (CHT) during the warm-up period. The lower the temperature, the more intense the initial warm-up period: the maximum warm-up duration is 8 seconds, assuming that average temperatures of -20°C prevail. At an engine temperature above 80°C, the warm-up device is completely switched off.

As soon as the cold engine starts moving, a period of additional heating of the glow plugs begins. This improves the idle running characteristics and minimizes hydrocarbon emissions after a cold start. The maximum duration of this period is 30 seconds at -20°C or even lower outside temperatures. At engine temperatures above 50°C, this period does not occur, as well as at engine speeds above 2500 rpm - this extends the service life of the glow plugs.



Each cylinder is heated by a separate spark plug: the Mondeo glow plugs have a very compact design – they operate without their own temperature regulation. This is not a disadvantage, since the sucked-in fresh air does not allow the plugs to burn out – the maximum temperature here is limited to about 1050°C.

Any failures or irregularities in the system's operation are "collected" by the electronic memory - its contents can only be read or erased in a contract workshop.

PRACTICAL ADVICE

Preheating device defective Defects in the turbodiesel preheater probably only become noticeable in freezing temperatures (-15°C). Only in this situation is the diesel unit reluctant to do its job without outside help. With due attention, possible defects can be detected at an early stage: when starting cold, pay attention to the exhaust gas. If unpleasant blue smoke plumes leave the exhaust pipe, you should read the information from the storage device at your service station - blue smoke signals "cold" combustion. Small clouds, of course, should not bother you.

The original article is available on the website fordbook.ru