C. Preglow System With Glow Plug Resistance Control (Mod 115.1)

Operation of Preglow System

C. Preglow system with glow plug resistance control engine 615, 616 in model 115.1

Operation

The mechanical-electrical preglow start and stop switch is a pull-push switch with four switch positions. stop position, drive position, preglow position and start position. In addition, the preglow start and stop switch is provided with a lock so that the key can be pulled off only in stop position.




Stop position
In stop position the knob of the pull-push switch is completely pushed in and the adjusting lever on injection pump is moved into full forward position by means of the Bowden wire. In this position of the adjusting lever the control rod is in "stop position, the pistons of the elements are at zero delivery, the engine receives no more fuel and will stop. In this position, the terminals 19, 50 and 17 are de-energized. The key on steering lock can be pulled off.




Drive position
In drive position, the Bowden wire with the oblong eye in relation to adjusting lever is located in such a manner that the eye is not resting against bolt of adjusting lever so that the adjusting lever is not actuated. When pulled out of stop position, the knob engages in the next following detent for the drive position. Terminals 19, 50 and 17 are de-energized. The key on steering lock cannot be pulled out.




Preglow position
After pulling knob out of drive position into preglow position, a small resistance will be felt. In this position, the switch must be held in place until the preglowing is completed.




In this position, terminal 19 is energized, glow plugs (1-4) will begin to glow via glow plug resistance control (5). Terminals 50 and 17 are de-energized.




Start position
When preglowing is completed, the knob is pulled completely up to stop after overcoming the minor resistance and is held in place until the engine fires.

In start position, the bolt of the adjusting lever rests against eye and is pullig the adjusting lever completely to the rear.

This will push the control rod beyond the full load stop and the injection pump will inject the starting fuel.

In starting position, terminals 50 and 17 are energized. The starter begins to function via terminal 50.

The glow plugs remain energized also in starting position via terminal 17.

To prevent the voltage drop on glow plugs from becoming too high during starting, the glow plug resistance control is bypassed.

When the knob of the pull-push switch is released, the switch will automatically return into driving position under the influence of springs.