GF47.30-P-3013GS Evaporative Emission Control System Function

GF47.30-P-3013GS Evaporative Emission Control System Function
- MODEL 170.449 with ENGINE 111.983
- with CODE (925) low emission EURO3





Shown on model 203
12 Cover the intake ports
55/1 Fuel filter with integrated diaphragm pressure regulator
75 Fuel tank
77 Activated charcoal canister
M3 Fuel pump (FP)
N3/10 ME-SFI [ME] control module
Y58/1 Purge control valve

The evaporative emission control system prevents fuel vapors escaping to atmosphere. The fuel vapors are temporarily stored in the activated charcoal canister (77) for this purpose.

When the engine is running, the fuel vapors stored in the activated charcoal canister are drawn off through the purge control valve (Y58/1) and combusted in the engine.

Purging of the activated charcoal canister takes place at:
- Coolant temperature greater than 70°C
- Greater than 2 minutes after engine start
- Engine not in deceleration mode

To control the purge quantity, the purge control valve (Y58/1) is operated by the ME-SFI control module (N3/10). The purge quantity is determined by constantly opening and closing the purge control valve for on and off periods of varying length.

The idle speed control prevents any changes in engine speed during purging. Depending on the amount of fuel vapors in the activated charcoal canister, the fuel-air mixture is made richer or leaner.

Air admission to fuel tank
Air is admitted through the activated charcoal canister. This is done by drawing air through the activated charcoal (77) out of the air admission line (a) and fuel vapors out of the activated charcoal canister into the fuel tank (75).

Air release from fuel tank
The air is released through the activated charcoal canister. This is achieved by the fuel vapors flowing to the activated charcoal canister where they are stored, or if the purge system is activated, they are extracted into the intake manifold (12).

Vent valve (model 170, 210)
On models fitted with a vent valve, air is released from the fuel tank as from a pressure of 30 - 50 mbar and air is admitted as from a vacuum of 1 - 16 mbar. This additionally prevents overfilling of the fuel tank.

(United States of America)
During refueling, the fuel vapors at the filler neck are recovered and passed to the activated charcoal canister (ORVR = Onboard Refueling Vapor Recovery). Large activated charcoal canister.

Engine 111 with supercharger
A check valve in the purge line prevents the charge pressure to the activated charcoal canister building up.