Knock sensor
Role
The knock sensor is a sensor of the piezo-electric type
The engine knock information, transmitted by the sensor, enables the ECU to correct the ignition advance (reduction)
Knock is a vibratory phenomenon due to an exploding combustion of the air/fuel mixture in one of the 4 cylinders
The sensor transmits voltage peaks to the injection ECU when there is knocking
After engine knocking information, the ECU reduces the ignition timing, and simultaneously enriches the air-fuel mixture
The knock sensor also detects the pre-ignition in the zone from 1800 to 4000 rpm close to full load referred to as "super knock"
If "super knock" is detected on one of the 4 cylinders, the engine ECU cuts off the injection on the cylinder concerned for 3 to 5 cycles
If the "super knock" continues, the engine ECU switches on the service warning lamp and reduces the performance of the engine
Location
(1) knock sensor
Electrical special features
Allocation of channels of connector
- Terminal 1: (+) signal
- Terminal 2: (-) signal
Engine speed sensor
Role
The role of the injection ECU in terms of the information received
- Checking the engine speed
- To determine the position of the crankshaft
- Calculation of the ignition advance
- To regulate the idle speed
It is a "HALL effect" type sensor
The engine speed sensor supplies an electrical signal each time a tooth of the target passes it (alteration of the magnetic field)
The 58 teeth are used to work out the engine speed
The 2 missing teeth are used to work out the crankshaft position (no signal)
Location
(2) target
(3) engine speed sensor
Electrical special features
Allocation of channels of connector
- Terminal 1: 5 volts supply
- Terminal 2: earth
- Terminal 3: signal
Camshaft position sensor
Role
The role of the injection ECU in terms of the information received
- To synchronise fuel injections with respect to the position of the pistons
- To recognise top dead centres
- To determine misfires
It is a "HALL effect" type sensor
The camshaft sensor provides a square signal for the injection ECU
Location
(4) camshaft position sensor
(5) Induction camshaft
Electrical special features
Allocation of channels of connector
- Terminal 1: + 5 volts supply
- Terminal 2: signal
- Terminal 3: earth
Signal emitted
- Presence of metal earth opposite the sensor: 0 Volts
- Absence of metal earth opposite the sensor: 12 Volts
Ignition coils
Role
Static ignition with one ignition coil per cylinder (pencil type)
The ignition coil supplies the plug with the high voltage
Location
(6) ignition coil
Electrical special features
Allocation of channels of connector
- "a" terminal 1: ignition control
- "b" terminal 2: 12 volts supply
- "c" terminal 3: earth
Sparking plugs
Special features
- Flat seat ignition plugs
- Tightening torque: 2,5 ± 0,1 daNm
Injection ECU
The coil command and power stages are incorporated into the ECU (there is no external ignition module)
The injection ECU supplies each primary of the coils alternately in the order of ignition (1-3-4-2)
The ignition is synchronised by the camshaft position sensor