Pre/post-heating

The recirculation is the "all or nothing" type (the solenoid valve is open or closed).

The injection control unit authorizes the opening of the solenoid valve to control the recirculation (when conditions decree)

The recirculation valve is subject to the vacuum coming from the vacuum pump and authorizes the recirculation of theh exhaust gases to the intake system.

Conditions that allow exhaust gas recirculation:

• engine speed above 780 rpm
• engine coolant temperature above 20°C

Conditions that prevent exhaust gas recirculation:

• engine at full speed
• engine speed above 3400 rpm
• altitude above 1500 m

EGR throttle:

• in conjunction with the recirculation valve, according to its position the throttle allows the improvement of the exhaust gas recirculation
• the throttle control is gradual and is managed by a map (injection control unit).

PRE/POST-HEATING

The pre and post-heating times are determined by the control unit depending on the temperature of the engine coolant.

Pre-heating operation

The pre-heating time varies according to the temperature of the engine coolant.

Heating of heater plugs during operation of starter motor

The heater plugs and the warning light start working when the engine is switched on.

Once the engine coolant temperature reaches 80°C, the warning light no longer stays on.

NOTE After the warning light has gone out, if the starter motor is not started, the heater plugs remain supplied for a maximum of 15 seconds.

Post-heating operation

Post-heating makes it possible to prolong the operation of the heater plugs during starting (3 minutes maximum).

Post-heating makes it possible to reduce pollutant emissions during the first few minutes after starting.