Flow chart
| BB00 | battery |
|---|---|
| BPGA | electrical supplies management and protection control unit |
| BSI1 | built-in systems interface |
| CA00 | ignition switch |
| PSF1 | engine fusebox |
| 0004 | instrument panel |
| 1158 | pre-postheating control unit |
| 1160 | pre-heater plugs |
| 1220 | engine coolant temperature sensor |
| 1320 | engine ECU |
| 4120 | engine oil level sensor (Oil temperature) |
| connection number | signal | transmitter/receiver | nature of signal |
|---|---|---|---|
| 1 | information: pre-post heating unit control fault | 1158 / 1320 | filament |
| 2 | engine coolant temperature information | 1220 / 1320 | filament |
| 3 | engine oil temperature information | 4120 / 1320 | filament |
| 4 | request for display of the preheating warning lamp | 1320 / BSI1 | CAN Is |
| 5 | request for display of the preheating warning lamp | PSF1 / BSI1 | Body CAN |
| 6 | request for display of the preheating warning lamp | 1320 / 0004 | CAN INFO DIV |
| 7 | control of the pre-postheating unit | 1320 / 1158 | filament |
| 8 | activation of the pre-postheating plugs | 1158 / 1160 | filament |
Pre-heating
Role
The preheater plugs enable the temperature to rise rapidly in the combustion chambers prior to the engine being started, when starting from cold or when the outside temperature is low
Role of preheating
- To facilitate starting from cold (the air is heated up to enable the injected diesel fuel to combust more easily)
- To reduce smoke emissions (the heated air reduces the incidence of unburnt gases)
NoteThe change from preheating to postheating occurs without interruption during the starting phase
Function
The engine ECU controls the pre-postheating control unit by means of an open cycle ratio
The electrical supply of the preheater plugs is via the pre-postheating control unit, as a function of the commands from the engine ECU
Phases of electrical supply of the preheater plugs
- Rapid heating
- Stabilised heating
The maximum activation time for rapid heating is no more than 2 seconds
The rapid heating phase enables the temperature of the preheater plugs to rise as rapidly as possible, to aid combustion
During the rapid heating phase, the pre-postheating control unit is controlled by an open cycle ratio of 99%
The stabilised heating phase comes in after the rapid heating phase, to maintain the temperature of the preheater plugs, while waiting for the engine to start
During the stabilised phase, the pre-postheating control unit is controlled by an open cycle ratio of around 60%
If a pre-post heating control unit failure occurs, the engine management ECU memorises a fault
The preheating times are determined by the engine ECU as a function of the following parameters
- Coolant temperature (measurement done by the engine coolant temperature sensor)
- Atmospheric pressure (measurement done by the atmospheric pressure sensor internal to the engine ECU)
Activation condition(s)
The pre-heating time varies as a function of the following values (duration of supply in seconds)
| engine coolant temperature | atmospheric pressure: 750 Mbar | atmospheric pressure: 799,8 Mbar | atmospheric pressure: 849,6 Mbar | atmospheric pressure: 900,4 Mbar |
|---|---|---|---|---|
| -40 °C | 7,9 seconds | 7,9 seconds | 7,9 seconds | 7,9 seconds |
| -30 °C | 7,9 seconds | 7,9 seconds | 7,9 seconds | 7,9 seconds |
| -25 °C | 7,9 seconds | 7,9 seconds | 7,9 seconds | 7,9 seconds |
| -18 °C | 7,9 seconds | 7,9 seconds | 7,9 seconds | 7,9 seconds |
| -10 °C | 7,9 seconds | 7,9 seconds | 7,9 seconds | 7,9 seconds |
| -5 °C | 7,9 seconds | 7,9 seconds | 7,9 seconds | 7,9 seconds |
| 0 °C | 7,9 seconds | 7,9 seconds | 7,9 seconds | 7,9 seconds |
| 4 °C | 7,9 seconds | 7,9 seconds | 7,9 seconds | 7,9 seconds |
| 5 °C | 7,9 seconds | 7,9 seconds | 7,9 seconds | 7,9 seconds |
| 10 °C | 7,9 seconds | 7,9 seconds | 5,2 seconds | 3,6 seconds |
| 20 °C | 7,9 seconds | 5,2 seconds | 3,6 seconds | 1,9 seconds |
| 30 °C | 5,2 seconds | 3,6 seconds | 1,9 seconds | 1,1 seconds |
| 40 °C | 3,6 seconds | 1,9 seconds | 1,1 seconds | 0,5 seconds |
| 50 °C | 1,9 seconds | 1,1 seconds | 0,5 seconds | 0 seconds |
| 55 °C | 1,1 seconds | 0,5 seconds | 0 seconds | 0 seconds |
| 60 °C | 0,5 seconds | 0 seconds | 0 seconds | 0 seconds |
| engine coolant temperature | atmospheric pressure: 950,2 Mbar | atmospheric pressure: 1000 Mbar | atmospheric pressure: 1049,8 Mbar | atmospheric pressure: 1199,2 Mbar |
|---|---|---|---|---|
| -40 °C | 7,9 | 7,9 | 7,9 seconds | 7,9 seconds |
| -30 °C | 7,9 | 7,9 | 7,9 seconds | 7,9 seconds |
| -25 °C | 7,9 | 7,9 | 7,9 seconds | 7,9 seconds |
| -18 °C | 7,9 | 7,9 | 7,9 seconds | 7,9 seconds |
| -10 °C | 7,9 | 7,9 | 7,9 seconds | 7,9 seconds |
| -5 °C | 7,9 seconds | 7,9 seconds | 7,9 seconds | 7,9 seconds |
| 0 °C | 7,9 seconds | 7,9 seconds | 7,9 seconds | 7,9 seconds |
| 4 °C | 7,9 seconds | 7,9 seconds | 7,9 seconds | 7,9 seconds |
| 5 °C | 5,2 seconds | 3,6 seconds | 2,2 seconds | 1,1 seconds |
| 10 °C | 1,9 seconds | 1,1 seconds | 0,5 seconds | 0 seconds |
| 20 °C | 1,1 seconds | 0,5 seconds | 0 seconds | 0 seconds |
| 30 °C | 0,5 seconds | 0 seconds | 0 seconds | 0 seconds |
| 40 °C | 0 seconds | 0 seconds | 0 seconds | 0 seconds |
| 50 °C | 0 seconds | 0 seconds | 0 seconds | 0 seconds |
| 55 °C | 0 seconds | 0 seconds | 0 seconds | 0 seconds |
| 60 °C | 0 seconds | 0 seconds | 0 seconds | 0 seconds |
NotePreheating can be ordered a second time if the engine does not start by the end of the first timing
Conditions of deactivation
During starting, the preheating phase ends as soon as one of the following conditions is met
- Coolant temperature above 60°C
- Continuous time of activation of the plugs greater than 180 seconds (10 seconds are required in order to be able to activate the plugs again)
- Battery voltage less than 6,5 volts
- Battery voltage greater than 16 volts
Post heating
Role
Within the first few seconds of the engine starting, the temperature in the combustion chambers does not permit a combustion of sufficient quality, this causing the engine to be unstable at idle and to emit excessive pollution
Role of postheating
- To prolong the operation of the preheater plugs after the cold starting phase
- To guarantee the correct quality of combustion after starting
- Reducing the emissions of pollutants in the first few minutes after starting
- To stabilise the engine at idle
- To compensate wear of the cat converter
- To reduce blue smoke emissions
- To aid regeneration of the particle filter
Function
The engine ECU controls the pre-postheating control unit by means of an open cycle ratio
The unit supplies the pre-heater plugs with power in accordance with the orders of the engine management ECU
If a pre-post heating control unit failure occurs, the engine management ECU memorises a fault
The postheating times are determined by the engine ECU as a function of the following elements
- The temperature of the coolant fluid (measured by the engine coolant temperature sensor)
- The atmospheric pressure sensor (measured by the atmospheric pressure sensor internal to the engine ECU)
NoteThe postheating timing can vary as a function of the inlet air temperature
Activation conditions
Reference values for postheating time (duration of supply in seconds)
| engine coolant temperature | atmospheric pressure: 799,8 Mbar | atmospheric pressure: 849,6 Mbar | atmospheric pressure: 900,4 Mbar | atmospheric pressure: 950,2 Mbar |
|---|---|---|---|---|
| -50 °C | 200 seconds | 200 seconds | 200 seconds | 200 seconds |
| -30 °C | 200 seconds | 200 seconds | 200 seconds | 200 seconds |
| -20 °C | 200 seconds | 200 seconds | 200 seconds | 200 seconds |
| -10 °C | 200 seconds | 200 seconds | 200 seconds | 200 seconds |
| 0 °C | 200 seconds | 200 seconds | 200 seconds | 200 seconds |
| 10 °C | 200 seconds | 200 seconds | 200 seconds | 200 seconds |
| 20 °C | 200 seconds | 200 seconds | 200 seconds | 200 seconds |
| 30 °C | 200 seconds | 200 seconds | 200 seconds | 200 seconds |
| 40 °C | 200 seconds | 200 seconds | 200 seconds | 200 seconds |
| 60 °C | 200 seconds | 200 seconds | 200 seconds | 200 seconds |
| 60,25 °C | 0 seconds | 0 seconds | 0 seconds | 0 seconds |
| 90 °C | 0 seconds | 0 seconds | 0 seconds | 0 seconds |
| 100 °C | 0 seconds | 0 seconds | 0 seconds | 0 seconds |
| 110 °C | 0 seconds | 0 seconds | 0 seconds | 0 seconds |
| 120 °C | 0 seconds | 0 seconds | 0 seconds | 0 seconds |
| 130 °C | 0 seconds | 0 seconds | 0 seconds | 0 seconds |
| engine coolant temperature | atmospheric pressure: 1000 Mbar | atmospheric pressure: 1049,8 Mbar | atmospheric pressure: 1150,4 Mbar | atmospheric pressure: 1199,6 Mbar |
|---|---|---|---|---|
| -50 °C | 200 seconds | 200 seconds | 200 seconds | 200 seconds |
| -30 °C | 200 seconds | 200 seconds | 200 seconds | 200 seconds |
| -20 °C | 200 seconds | 200 seconds | 200 seconds | 200 seconds |
| -10 °C | 200 seconds | 200 seconds | 200 seconds | 200 seconds |
| 0 °C | 200 seconds | 200 seconds | 200 seconds | 200 seconds |
| 10 °C | 200 seconds | 200 seconds | 200 seconds | 200 seconds |
| 20 °C | 200 seconds | 200 seconds | 200 seconds | 200 seconds |
| 30 °C | 200 seconds | 200 seconds | 200 seconds | 200 seconds |
| 40 °C | 200 seconds | 200 seconds | 200 seconds | 200 seconds |
| 60 °C | 200 seconds | 200 seconds | 200 seconds | 200 seconds |
| 60,25 °C | 0 seconds | 0 seconds | 0 seconds | 0 seconds |
| 90 °C | 0 seconds | 0 seconds | 0 seconds | 0 seconds |
| 100 °C | 0 seconds | 0 seconds | 0 seconds | 0 seconds |
| 110 °C | 0 seconds | 0 seconds | 0 seconds | 0 seconds |
| 120 °C | 0 seconds | 0 seconds | 0 seconds | 0 seconds |
| 130 °C | 0 seconds | 0 seconds | 0 seconds | 0 seconds |
Conditions of deactivation
The postheating phase ends if one of the following conditions is met
- Coolant temperature above 60°C
- Battery voltage less than 6,5 volts
- Battery voltage greater than 16 volts
The glow plugs are only activated when the engine is operating in medium load conditions, in order to prevent the engine overheating
Activation of the postheating for compensation of wear of the cat converter
Damage to the cat converter is compensated by the activation of the postheating, provided the following conditions are met
- Outside air temperature between 13°C and 30°C
- Atmospheric pressure less than 950 mbar
- Distance travelled by the vehicle between 0 km and 160000 km
Provided the activation conditions are met, the timing of the activation of the preheater plugs is calculated as a function of a special calibration taking account of a cat converter ageing factor
Activation of the postheating for reduction of blue smoke at altitude
In order to limit the emission of blue smoke, notably at altitude (atmospheric pressure less than 900 mbar), the preheater plugs are activated according to a mapping that takes into account the following parameters
- Inlet air temperature
- Engine coolant temperature
- Engine torque
Activation of the postheating for aid in regeneration of the particle filter
During regeneration, the preheater plugs can be activated by the BSI1 through the engine ECU
The objective is to load the engine, so as to increase its temperature to give it the engine temperature conditions that are ideal for regenerating the particle filter
The glow plugs are only activated when the engine is operating in medium load conditions, in order to prevent the engine overheating
The maximum operating time for the preheater plugs is 180 seconds, even if the request from the BSI1 is continuous