Schematic diagram
Key
- "A" air inlet
- "B" fuel vapours
- "C" fuel
- "D" electrical links
| reference | designation | electrical diagram correspondence |
|---|---|---|
| (1) | engine ECU | 1320 |
| (2) | motorised throttle | 1262 |
| (3) | purge canister solenoid valve | 1215 |
| (4) | fuel tank | - |
| (5) | fuel vapour absorber | - |
| (6) | canister | - |
Phases of operation
When the engine is switched off, the canister discharge electrovalve is closed: the canister absorbs the fuel vapours coming from the tank
When the engine is running, the engine management ECU estimates the load in the canister by progressively opening the canister discharge electrovalve in order to measure the change in the richness of the air/fuel mixture admitted into the engine
As the engine management ECU knows the output of the canister discharge electrovalve, it uses this to deduce the load in the canister
The engine management ECU reduces the injector flow and controls the canister discharge electrovalve to obtain the overall quantity of fuel to be injected into the engine
The control of the canister discharge electrovalve corresponds to a percentage discharging of the canister which varies in accordance with the engine speed and the engine load
The engine control ECU, controls the motorised throttle unit to obtain a vacuum in the inlet manifold
When the canister discharge electrovalve is open, the vacuum in the inlet manifold allows the vapours stored in the canister to be drawn in