Purge Control Valve Actuation Function

Purge Control Valve Actuation Function




Shown on engine 119 in model 129, 140
75 Fuel tank
77 Activated charcoal canister
B2/5 Hot film mass air flow sensor
B11/4 Coolant temperature sensor
B17 Intake air temperature sensor
L5 Crankshaft position sensor
M16/1 Electronic accelerator (EA)/ cruise control (CC)/ idle speed control (ISC) actuator
N3/10 ME-SFI control unit
N16/1 Base module
Y58/1 Purge control valve

For controlling the purge quantity the purge control valve is actuated at the ground side by the ME-SFI control unit by means of a pulse width-modulated signal. The purge quantity is determined by constantly opening and closing the purge control valve for on and off periods of various lengths.

The frequency of the pulse width modulation signal is selected from a speed-dependent characteristic in such a way, that all cylinders are uniformly supplied with fuel vapors.

The purge control valve is actuated when the engine is at operating temperature, but not in the deceleration mode.

The following information is processed in the ME-SFI control unit:
- Engine speed
- Air mass (boost pressure in supercharged engines)
- Coolant temperature
- Intake air temperature (charge air temperature in supercharged engines)