Schematic diagram
| reference | designation | electrical diagram correspondence |
|---|---|---|
| "A" | electrical connection | - |
| (1) | engine speed sensor | 1313 |
| (2) | cylinder reference sensor | 1115 |
| (3) | knock sensor | 1120 |
| (4) | ignition coils | 1131, 1132, 1133, 1134 |
| (5) | spark plugs | - |
| (6) | engine ECU | 1320 |
Principle of the ignition
The ignition is the operation that consists of causing and maintaining the combustion of the air-petrol mixture sucked in by the pistons into the cylinders of the engine
The air-petrol mixture is ignited by the spark produced by the spark plugs
The air-petrol mixture ignites in concentric layers and so the ignition must be advanced to take account of the duration of combustion
Principle of ignition advance
By causing the ignition before the piston reaches top dead centre (TDC), the force exercised on the piston is at the maximum as soon as it goes past it
The interval in degrees before the instant at which the spark jumps and top dead centre (TDC) measures the ignition advance
The calculation of the ignition advance depends on the following parameters
- Engine speed
- Knock information
- Positioning of the inlet camshaft
- Richness of the air-petrol mixture
Engine ECU
The power and control stages of the coils are incorporated in the engine management ECU (there is no external ignition module)
The engine management 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