Presentation
Functions of the engine management ECU
- To control the cutting in and cutting out of the cooling fan(s) (engine cooling)
- Control of the post ventilation (for a maximum of 6 minutes)
- To control the lighting of the coolant temperature warning lamp in the control panel
- Control of the coolant temperature logometer on the instrument panel
- To carry out a diagnostic check of the operation of the cooling fan(s)
- Acquisition of the engine coolant temperature
- To manage the back-up modes
Variable speed assembly
Flow chart
Key
- Single arrow: wire connection
- Triple arrow: multiplexed connection
| designation | part number in the electrical diagrams |
|---|---|
| built-in systems interface | BSI1 |
| instrument panel | 0004 |
| engine coolant temperature sensor | 1220 |
| engine ECU | 1320 |
| fan | 1510 |
| variable speed cooling fan electronic unit | 1521 |
| link | description | transmitter/receiver | nature of signal |
|---|---|---|---|
| 1 | engine coolant temperature information | 1220 / 1320 | analogue |
| 2 | control of the variable speed cooling fan control unit (chopper) | 1320 / 1521 | analogue |
| 3 | control of the variable speed cooling fan | 1521 / 1510 | analogue |
| 4 | request for triggering of the cooling fan | BSI1 / 1320 | CAN Is |
| 5 | sending of the coolant temperature information | 1320 / BSI1 | CAN Is |
| recouple the rear controlled rod | |||
| 6 | control of lighting of the coolant temperature alert warning lamp | BSI1 / 0004 | COMFORT CAN |
| coolant temperature indicator | |||
| request to illuminate the diagnostic LED (MIL) | |||
| 7 | confirmation of lighting of coolant indicator and warning lamps | 0004 / BSI1 | COMFORT CAN |
| user requests |
Cooling fan controlled by electronic chopper
Depending on the vehicles, the DW10BTED4 engines are equipped with a cooling fan piloted by chopper
Required cooling fan speed as a function of the air conditioning circuit pressure
Key
- "A": cooling fan speed (% of maximum speed)
- "B": (OCR = opening cycle ratio), as a percentage
Stopping is commanded by the low status of the cooling fan control (Descending front)
In operation, the signal commanding the cooling fan varies in the range between 16 % and 80 %
If there is a malfunction in the engine temperature information system, the engine ECU commands the activation of the cooling fan (GMV) and requests the lighting of the diagnostic warning lamp (MIL)
NoteCheck the operation of the cooling fan; using the diagnostic equipment. the values displayed are actual, not estimated (via parameter measures as well as via actuator tests)
2-speed assembly
WarningThe fan triggering levels depend on the vehicle: refer to the relevant documentation
Flow chart
Key
- Single arrow: wire connection
- Triple arrow: multiplexed connection
| designation | part number in the electrical diagrams |
|---|---|
| built-in systems interface | BSI1 |
| instrument panel | 0004 |
| engine coolant temperature sensor | 1220 |
| engine ECU | 1320 |
| fan | 1510 |
| dual speed fan electronic control unit | 1522 |
| link | description | transmitter/receiver | nature of signal |
|---|---|---|---|
| 8 | engine coolant temperature information | 1220 / 1320 | analogue |
| 9 | installation on front RH wheelarch | 1320 / 1522 | analogue |
| 10 | cooling fan confirmation active | 1510 / 1320 | all or nothing |
| 11 | command for activation of the cooling fan | 1522 / 1510 | analogue |
| 12 | request for triggering of the cooling fan | BSI1 / 1320 | CAN Is |
| 13 | sending of the coolant temperature information | 1320 / BSI1 | CAN Is |
| recouple the rear controlled rod | |||
| 14 | control of lighting of the coolant temperature alert warning lamp | BSI1 / 0004 | COMFORT CAN |
| coolant temperature indicator | |||
| request to illuminate the diagnostic LED (MIL) | |||
| 15 | confirmation of lighting of coolant indicator and warning lamps | 0004 / BSI1 | COMFORT CAN |
| user requests |
2 speed cooling fan
Depending on the vehicles, DW10BTED4 engines are equipped with a 2-speed cooling fan
Calculating the fan unit speed
The engine ECU fixes the required speed for the cooling fan as a functionof the following parameters
- The engine coolant temperature measured by the sensor (1220)
- The cooling requirement associated with the air conditioning (managed internally to the mapping)
Checking the fan unit speed
The fan unit is fitted with 2 functioning speeds. the engine ECU commands the activation of the slow and the fast speed via the cooling fan electrical control unit (1522). the BSI commands the medium speed, as a function of the information delivered by the engine ECU via the CAN IS network (fixing on the suspension support)
Description
| event | action |
|---|---|
| "a" | cooling fan unit speeds triggering thresholds |
| "b" | fan unit speeds untriggering limits |
| "C" | high speed (102°C) |
| "D" | temperature in degrees Celsius |
| "E" | slow speed (97°C) |
Cooling system
(16) header tank
(17) heater matrix
(18) coolant outlet housing
(19) engine cooling radiator
(20) water inlet housing
Engine coolant temperature sensor (1220)
The engine coolant temperature sensor informs the ECU about the engine coolant temperature
The coolant temperature sensor is installed on the coolant outlet housing
(18) coolant outlet housing
(21) engine coolant temperature sensor
| temperature | resistance value |
|---|---|
| -30 °C | 88500 ohms |
| -20 °C | 48535 ohms |
| -10 °C | 27665 ohms |
| 0 °C | 16325 ohms |
| 10 °C | 9950 ohms |
| 20 °C | 6245 ohms |
| 40 °C | 2663,5 ohms |
| 60 °C | 1244 ohms |
| 80 °C | 629 ohms |
| 90 °C | 458,9 ohms |
| 100 °C | 340 ohms |
| 110 °C | 255,6 ohms |
| 120 °C | 194,7 ohms |
Post ventilation
When the engine stops, the ECU will operate the post-cooling if the coolant temperature exceeds a certain threshold (*) (105°C)
(*) depending on vehicle
Post-cooling occurs at slow speed and lasts for a maximum of 6 minutes after the engine has stopped
Function
Fan regulation internal control (FRIC)
The FRIC strategy allows the engine cooling fan (GMV) to be kept operating both while the engine is running and also after it has stopped
The FRIC system takes into account the temperature of the coolant fluid as well as the ventilation needs of the following functions
- The air conditioning
- The automatic gearbox requirements for cooling of the oil/coolant exchanger
The FRIC system also controls the cooling fan (GMV) for the particle filter (FAP)
The FRIC system informs, either wire to wire or by multiplexed line, the other engine management functions on
- The coolant temperature information for different systems
- The coolant temperature alert for the warning lamp on the dashboard
- The request for cutting off the air conditioning compressor
- Speed setpoint data applied to the fan unit (GMV)
- The supply that is necessary to the electronic circuits of the cooling fan (GMV) during the operating phase
- The retaining of an emergency operating mode in the event of a failure of one of the elements of the cooling system seen by the engine management ECU (CMM)
Functions assured by the engine ECU
FRIC operating laws
- Estimation of the punctured torque (idling management) or compensation
- Augmentation of the (reference) idling speed required for the electrical balance and/or the performance of the air conditioning compressor
- Protection of the air conditioning compressor
- Command of the cooling fan (GMV) at a speed at least equal to the needs of FRIC
- Sending of the information relating to the cooling fan (GMV) on the CAN IS network
- Engine protection (over-heating)
Back-up mode
Role of the engine ECU if there is a failure of the coolant temperature sensor
- To control operation of the fan at high speed
- To control the lighting of the coolant temperature alert warning lamp on the instrument panel (depending on the version)
- Prohibiting of control of the air conditioning compressor (AC/OUT)