Flow chart
Channel J1 of the 48-way connector (CMI): input: diagnostic signal of the pre-postheating unit
Channel A2 of the 48-way connector (CME): control of the pre-postheating unit
| designation | components |
|---|---|
| 1320 | engine ECU |
| BSI1 | built-in systems interface |
| 1158 | pre-post heating control unit |
| 1160 | pre-heater plugs |
| 0004 | instrument panel |
| no. of link | signal | nature of signal |
|---|---|---|
| 1 | request for lighting of pre-heater warning lamp | CAN Is |
| 2 | lighting of pre-heater warning lamp | COMFORT CAN |
Pre-heater plugs (1160)
Role
The pre-post heating glow plugs allow a rapid temperature rise in the combustion chambers during the starting phase
Description
Composition of the pre-heat glow plugs
- A heating resistor
- A metallic protective cover
Pre-post heating control unit (1158)
Role
The unit supplies the pre-heater plugs with power in accordance with the orders of the engine management ECU
Description
The pre-postheating times are determined by the engine ECU
If a pre-post heating control unit failure occurs, the engine management ECU memorises a fault
Electrical special features
| terminal | function |
|---|---|
| N°1 | supply of pre-heater plug, cylinder N°3 |
| N°2 | supply of pre-heater plug, cylinder N°1 |
| N°3 | diagnosis |
| N°4 | battery supply |
| N°5 | internal earth (taken directly on the unit) |
| N°6 | supply of pre-heater plug, cylinder N°4 |
| N°7 | supply of pre-heater plug, cylinder N°2 |
| N°8 | control |
Location
(3) electrical harness
(4) pre-heater plug
(5) pre-post heat box
Pre-heating and postheating
The times for pre-heating and post-heating are determined by the engine ECU as a function of the temperature of the engine coolant fluid at idling speed and at altitude
The duration of activation of the plugs for the pre-heating before starting depends on the coolant temperature and the atmospheric pressure
The pre-heating during starting phase takes place if the engine coolant temperature is below 25 °C. this phase begins when the engine speed has exceeded 70 rpm for more than 100 ms
Pre-heating operating time in relation to the engine coolant temperature
Key
- Time (ms)
- Engine coolant temperature (°C)
Pre-heating operating time in relation to the atmospheric pressure and the engine coolant temperature
Pre-heating time (ms)
| engine coolant temperature (°C) | atmospheric pressure: 697 to 725 hPa | atmospheric pressure: 750 to 775 hPa | atmospheric pressure: 800 to 825 hPa | atmospheric pressure: 850 to 875 hPa | atmospheric pressure: 900 to 925 hPa | atmospheric pressure: 950 to 1000 hPa |
|---|---|---|---|---|---|---|
| -30 | 18000 | 18000 | 18000 | 18000 | 18000 | 18000 |
| -25 | ||||||
| -20 | 15000 | 15000 | 14500 | 14500 | 12000 | 10000 |
| -15 | ||||||
| -10 | 9500 | 9000 | 8250 | 7500 | 7000 | 5000 |
| -5 | ||||||
| 0 | 3000 | 3000 | 3000 | 3000 | 3000 | 3000 |
| 5 | 2000 | 1500 | 1500 | 1500 | 1500 | 1500 |
| 10 | 1000 | 1000 | 750 | 500 | 0 | 0 |
| 20 | 500 | 500 | 500 | 0 | ||
| 30 | 0 | 0 | 0 | |||
| 40 | ||||||
| 50 | ||||||
| 60 | ||||||
| 70 | ||||||
| 80 |
Pre-heating deactivation conditions
The pre-heating during starting phase ends when the following conditions are met
- Coolant temperature above 25°C
- Plug activation time longer than 60 seconds
- Battery voltage less than 6,5 volts
The starting phase has ended, engine speed above a threshold which depends on the coolant temperature and the atmospheric pressure
| engine coolant temperature (°C) | atmospheric pressure: 700 hPa | atmospheric pressure: 850 hPa | atmospheric pressure: 900 hPa | atmospheric pressure: 950 hPa |
|---|---|---|---|---|
| -30 | 1350 | 1300 | 1275 | 1250 |
| -18 | 1250 | 1200 | 1175 | 1150 |
| -10 | 1120 | 1070 | 1045 | 1020 |
| 0 | 1050 | 1000 | 975 | 950 |
| 5 | 990 | 940 | 915 | 890 |
| 20 | 960 | 910 | 885 | 860 |
| 90 | 930 | 880 | 855 | 830 |
Postheating operation
The postheating serves to prolong the operation of the pre-heating plugs after the cold starting phase
The post-heating enables the emission of pollutants in the first few minutes after starting to be reduced
The postheating reduces the emission of blue smoke
Parameters which could interrupt post-heating
- Flow injected
- Flow of fuel
- Engine coolant temperature
- Air temperature
Postheating for reduction of the CO/HC
| engine coolant temperature (°C) | post-heating duration (s) |
|---|---|
| -30 | 180 |
| -20 | 180 |
| 0 | 180 |
| 10 | 180 |
| 18 | 180 |
| 30 | 180 |
| 40 | 1.5 |
| 50 | 0 |
| injection quantity (mg/stroke) | engine speed 0 rpm | engine speed 1250 rpm | engine speed 1350 rpm | engine speed 2500 rpm | engine speed 2750 rpm | engine speed 3500 rpm | engine speed 3750 rpm |
|---|---|---|---|---|---|---|---|
| 100 | cut-off | - | - | - | - | - | - |
| 100 | - | cut-off | - | - | - | - | - |
| 30 | - | - | cut-off | - | - | - | - |
| 30 | - | - | - | cut-off | - | - | - |
| 10 | - | - | - | - | cut-off | - | - |
| 10 | - | - | - | - | - | cut-off | - |
| 0 | - | - | - | - | - | - | cut-off |
Postheating permitting the reduction of blue smoke
Calibration of activation at altitude in relation to the engine speed and the flow of fuel (>1000m)
| flow of fuel (mg/stroke) | engine speed 0 rpm | engine speed 700 rpm | engine speed 1500 rpm | engine speed 2000 rpm | engine speed 2500 rpm | engine speed 3500 rpm | engine speed 4000 rpm | engine speed 4500 rpm |
|---|---|---|---|---|---|---|---|---|
| 0 | 0 | 1 | 1 | 1 | 1 | 1 | 0 | 0 |
| 1 | 0 | 1 | 1 | 1 | 1 | 1 | 0 | 0 |
| 4 | 0 | 1 | 1 | 1 | 1 | 1 | 0 | 0 |
| 6 | 0 | 1 | 1 | 1 | 1 | 1 | 0 | 0 |
| 8 | 0 | 1 | 1 | 1 | 1 | 1 | 0 | 0 |
| 10 | 0 | 1 | 1 | 1 | 1 | 1 | 0 | 0 |
| 12 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| 50 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
Calibration of activation at altitude in relation to the coolant and air temperature (>1000m)
Post-heating duration (s)
| coolant temperature (°C) | air temperature: -20 °C | air temperature: -10 °C | air temperature: 0 °C | air temperature: 10 °C | air temperature: 20 °C | air temperature: 40 °C | air temperature: 60 °C |
|---|---|---|---|---|---|---|---|
| -20 | 1 | 1 | 1 | 1 | 1 | 1 | 0 |
| -10 | 1 | 1 | 1 | 1 | 1 | 1 | 0 |
| 0 | 1 | 1 | 1 | 1 | 1 | 1 | 0 |
| 20 | 1 | 1 | 1 | 1 | 1 | 1 | 0 |
| 70 | 1 | 1 | 1 | 1 | 1 | 1 | 0 |
| 90 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
Operation of the postheating during the regeneration phase
During the regeneration, the plugs may be activated by the BSI via the engine management ECU
The objective is to load the engine to increase the engine temperature and make it possible to obtain the ideal engine temperature conditions for regeneration of the particle filter
The plugs are only activated when the engine is operating under medium load conditions, to prevent overheating of the engine
The maximum timed operation of the plugs is 50 seconds, even if the request from the BSI is continuous. The activation of the pre-heater plugs is reactivated after a delay of 1 second
The activation of the plugs is stopped when
- Engine speed is higher than 2500 rpm
- The system flow is higher than 25 mg/stroke