Direct Petrol Injection System with Bosch Motronic MED 7 - Volkspage

Activated charcoal canister system
This is necessary in order to meet the statutory
requirements relating to hydrocarbon emissions
(HC). It prevents fuel vapour from escaping the
fuel tank to the surrounding atmosphere. Fuel
vapour is stored in the activated charcoal
canister and burned off at periodic intervals.
In homogeneous lean charge mode and in homogeneous charge mode,
the ignitable mixture is evenly distributed inside the combustion chamber. So the combustion process
takes place in the whole of the combustion chamber. The fuel discharged from the activated charcoal
canister system is also burned.
In stratified charge mode,
the ignitable mixture is present only in the area of the spark plugs. However, a portion of the fuel from
the activated charcoal canister system is located in the non-ignitable outer region. This can lead to
incomplete combustion and an increase in HC emissions in the exhaust gas. For this reason, stratified
charge mode is only allowed if a low activated charcoal canister load is calculated.
The engine control unit calculates how much fuel
may be fed from the activated charcoal canister
system.
Then the solenoid valve is activated, the injection
quantity is adapted and the throttle valve is
adjusted.
N30 -33
N80
J220
G70/G42 G28 G39
As a result, the engine control unit requires the
following information:
J338
- the engine load from the
hot-film air mass meter (G70)
- the engine speed from the
engine speed sender (G28)
- the intake air temperature from the intake air
temperature sender (G42), and
- the load state of the activated charcoal canister
from the lambda probe (G39)
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