3.3.18. Injection device

PRINCIPLE OF OPERATION OF THE DIESEL ENGINE

In the diesel engine clean air is sucked in in cylinders and there is exposed to very high extent of compression. At the expense of it temperature in cylinders increases higher than temperature of ignition of diesel fuel. Diesel fuel ignites in itself, thus spark plugs are not required here.

On the cold engine of temperature of ignition of fuel only due to compression it is impossible to reach. In this case it is made having warmed up (prechannel) of the engine. For this purpose in each vortex camera of the engine there is a glow plug warming the combustion chamber.

Fuel is sucked in by directly distributive pump of injection from the fuel tank. The pump of injection creates the necessary high pressure (about 130 bars) which is distributed on cylinders in compliance and with the necessary sequence of ignition. At the same time the regulator of the pump of injection doses supply of fuel depending on extent of involvement of the accelerator pedal. At a given time diesel fuel is injected through nozzles in a forkamer of the corresponding cylinder. Depending on a form forkamer, or the vortex camera the soaked-up air as a result of compression gets whirl that promotes optimum mixing of air and the injected fuel.

Before hit in the pump fuel passes through the fuel filter. There it is cleared of pollution and water. Therefore it is especially important to merge water from the filter or to replace it according to regulations of service.

The pump of injection does not demand service. All mobile details of the pump are greased with diesel fuel. The pump is given from a bent shaft through a gear belt from which also the camshaft is given.

Working according to the scheme of spontaneous ignition, the diesel engine cannot be switched off by removal of tension of ignition and has for this purpose the magnetic valve. At switching off of the lock of ignition food from the magnetic valve is removed and it locks the channel of supply of fuel. Thanks to it it is guaranteed that supply of fuel is interrupted before blocking of a steering wheel at taking out of the ignition key. At start of the engine tension moves via the ignition lock switch on the magnetic valve and it opens the channel of supply of fuel.

PREHEAT DEVICE

On the cold engine of temperature of ignition of fuel only due to compression it is impossible to reach therefore the engine needs to be warmed. For this purpose in each combustion chamber the rod candle of a preincandescence is screwed. The glow plug consists generally of the case and the heating core pressed in it. As soon as tension is applied, the incandescence spiral in a heating core within several seconds is warmed up to the temperature of 850 °C thanks to what the warming up period before start-up lasts seldom more, than 10 seconds. After blackout on the control panel of a control lamp of preheat the engine can be started. Duration of a warming up is regulated by the electronic control unit which is in salon near a glove box on the right. The control unit of preheat of the engine obtains information on engine temperature from the sensor of temperature of cooling liquid. On the basis of the obtained information the control unit determines duration and size of current of a prenakal.

Check of system of preliminary heat

If there are difficulties at start of the engine, at first it is necessary to check an engine compression. If pressure of a compression is not enough, the engine is not started at low temperatures. If a compression as it should be, check work of all candles of an incandescence.

Check conditions

The rechargeable battery is charged completely, tension of the battery has to make at least 12B. The engine cold (air temperature) or temperature of the engine is below +60 °C. At more high temperature of the engine disconnect the plug from the sensor of temperature of cooling liquid.

Check of giving of current

This check can be made without removal of candles of an incandescence.

PERFORMANCE ORDER

1. Connect the voltmeter between a glow plug and weight. 2. Insert a key into the lock of ignition and include preheat. In 3 sec. tension of the battery (12B) has to appear, otherwise check contacts of the switch of the lock. 3. Then muffle ignition, and include preheat. The measuring device for 20 sec. has to show battery tension (12B or above). Time depends on temperature of a glow plug, tension of the battery, temperature of cooling liquid and on position of the switch of an ignition / starter between VKL and VYKL. 4. Switch-off the plug S on a starter that the starter could not work. 5. For a short time turn the ignition key on "Start-up" and stop in situation "VKL Ignition". The voltmeter for 20 sec. has to show battery tension (12B or above). 6. Connect the plug S to a starter. 7. Start the engine and leave to idle. The voltmeter in 5 min. has to show battery tension (12B or above), presumably temperature of cooling liquid is below 60 °C. 8. If there is no giving of current, give the monitor of system of preliminary heat for check to a workshop.

Check of the relay of management of preheat

PERFORMANCE ORDER

1. Remove the relay. 2. Check the relay coil an ohmmeter for breakdown (0 Ohms). 3. Connect an ohmmeter to a relay exit. Connection has to be present. 4. Apply battery tension to contacts of the coil. The relay has to switch and resistance at the exit has to make 0 Ohms. 5. Otherwise replace the relay.

Check of candles of an incandescence

PERFORMANCE ORDER

1. Check the current carrying tire for formation of a rust, if necessary clear or replace. 2. Check a spark plug for external noticeable damages. 3. Disconnect the monitor plug heating. Connect an ohmmeter between the plug 5 of the plug and weight. Has to be: 0 Ohms, differently replace a wire. 4. Unscrew a cable of connection and the current carrying tire of a glow plug. 5. Check an ohmmeter resistance between the plug of a glow plug and the block of the engine (weight). There have to be 0 Ohms. If the break is found, replace a candle. 6. Thus check all candles. Prevention True resistance of a glow plug is not enough and it is difficult to measure it usual measuring by devices. The required value: 0,650 Ohms. Before measurement the candle should be cleared of oil. 7. Turn out a faulty glow plug and replace. 8. Screw a cable of connection and the current carrying tire, previously having established spring and lining washers on a candle. 9. If it is disconnected, connect the plug of the sensor of temperature of cooling liquid. Prevention If malfunction is not found, however the engine is started badly, it is necessary to examine candles at the moment of heat. For this purpose remove nozzles and examine candles through openings. Glow plugs with the burned tips 10. The burned tips of candles are generally a consequence of faulty nozzles. 11. If similar candles (shooter) are found, it is only enough to replace of them. 12. It is necessary to carry out an inspection of nozzles on pressure of injection and tightness (it is carried out in a workshop).

Check of the sensor of temperature of cooling liquid

PERFORMANCE ORDER

1. Remove temperature sensor. 2. Connect an ohmmeter to contacts of the sensor, and then for check or to cool cooling аэрозолью, or to heat in a water bath.

The required values

Temperature	Resistance
– 15 °C	11,5 kOhm
0 °C	5,6 kOhm
+ 10 °C	3,7 kOhm
+ 40 °C	1,2 kOhm

Check of contacts of the switch of the lock of ignition

PERFORMANCE ORDER

1. Remove the lower facing of a steering column. 2. Disunite the ignition lock socket. 3. Connect an ohmmeter to the plug (1) and check resistance (2 – the plug to the switch of ignition and starter). Connection has to be absent. 4. Insert a key into the ignition lock. Resistance has to make up to 0 Ohms, otherwise replace the ignition lock switch. 5. Establish the lower facing of a steering column.