Electronic pre-heating device

ELECTRONIC PRE-HEATING DEVICE

The electronic pre-heating device comprises:

• a control unit in the engine compartment;
• 4 rapid type heater plugs located in the ante-chambers in the engine cylinder head;
• a heater plug warning light in the dashboard.

The aim of the above mentioned device is to ensure the following functions:

1. To supply a high pre-heating current from the battery to the heater plugs for a variable time depending on the temperature in the engine compartment, before starting.
   The engine compartment temperature is measured by an NTC sensor inside the heater plugs control unit.
   Pre-heating serves the purpose of bringing the temperature in the ante-chambers to values which facilitate the self-ignition of the fuel, thereby making starting easier.
2. To keep the heater plugs warning light on for a variable period, depending on the temperature in the engine compartment from 1,2 ÷ 4,5 secs at 50°C, up to a maximum of 20 ÷ 27 secs at -20°C. When the warning light goes out it means it is possible to start up the engine.
3. To ensure that for a given period of around 20 secs the heter plugs still remain supplied if starting has not taken place in that time.
4. If, however, the engine has been started, the pre-heating control unit should ensure the continuation of the supply to the heater plugs for a so-called post-heating period lasting around 15 - 20 secs from starting , in order to reduce excessive smoke when the engine is first running.
5. If the engine has not been started, the control unit should, after the given time has elapsed, cut off the current supply from the battery to the heater plugs.
6. Lastly, if one of the heater plugs or current cables is put accidentally to earth, the pre-heating control unit should immediately de-activate the current supply from the system.

Location of pre-heating device in engine compartment

Pre-heating control unit with cover removed