Cold start device diagram
1 - device for controlling the preheating device; 2 - high pressure fuel pump (injection pump); 3 - engine; 4 - glow plugs; 5 - lever for normal and accelerated x. X.; 6 - full load microswitch (idling circuit is off); 7 - solenoid valve of the device for starting a cold engine; 8 - thermal switch of the device for starting a cold engine; 9 - thermoelement in the coolant circulation system.
The following connections are listed below: «+APC» - switched plus; «TEM» - to the preheat control lamp; «+dem» - to the starter; «+bat» - from the rechargeable battery; «-bat» - to the mass.
The drawing of the diesel engine compartment shows the layout of the wiring to the most important elements of the preheater. Who does not know the individual elements.
Heat
When starting a cold engine, the injected fuel must be ignited in the diesel swirl chamber by glow plugs. To do this, a glow plug is screwed into the swirl chamber of each cylinder, which additionally heats up and ignites the intake air and injected fuel that have already been heated by compression for a few seconds.
Functions of the preheater
By turning the key to the second position in the ignition switch, you switch on the preheating. This gives the preheater control unit (located in the engine compartment on the left side of the front wall) command «start warming up the engine».
How long the heating should last is determined by the control unit itself.
The control unit receives information about the temperature via a temperature sensor, which registers the ambient temperature and then determines the duration of the pre-heating and post-heating phases. Then the heating goes on independently in 3 stages.
1. When enabled «ignition» glow plugs are heated to over 1000°C. The preheating time is limited by the control unit depending on the outside temperature. At an outside temperature of -30°C, the preheating time lasts about 20 seconds, while when the engine is warmed up to operating temperature (80°C) it equals zero.
2. When starting the engine, the temperature of the glow plugs drops, which is caused by a high current consumption of the starter.
3. After the engine has started, the glow plugs remain on in the post-heating phase for about 10 seconds.
4. If the engine coolant temperature was above 60°C when the engine was started, the thermal switch in the coolant circulation system turns off the electrical circuit and the subsequent warm-up is not carried out with the engine running.
5. At the end of the subsequent heating of the glow plug, at the command of the control device, alternately (respectively, 2 to 2 glow plugs) and, depending on the outside temperature, receive 50% of the electric power to improve the quality of the cold engine.
Note. Recommendation: if the starter cranks the engine for too long when starting, the starting process must be repeated, since the automation has already interrupted the glow plugs. In this case, the preheater control must activate the glow plugs again.
If you forget to preheat the engine, the starter will crank the engine for as long as necessary for preheating until the mixture is ready to ignite. The fuel accumulated before the start of the engine is then removed as unburned blue smoke.