Fuel evaporation control system - RA4700FLH0200X(47-0200)

WARNING: This page does not describe the selected car, but rather 42 other vehicles, including the 1999 Mercedes-Benz S600, 1999 Mercedes-Benz S500, 1999 Mercedes-Benz S420, 1999 Mercedes-Benz S320, and 1999 Mercedes-Benz CL600. However, it is still accessible from the selected car via links, so may be relevant.

A. Function diagram

a) Engine 104

Fig 1: Fuel Evaporation Control System Function Diagram (Engine 104)

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

b) Engine 119

Fig 2: Fuel Evaporation Control System Function Diagram (Engine 119)

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

c) Engine 120

Fig 3: Fuel Evaporation Control System Function Diagram (Engine 120)

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

d) Vehicles with through-loading facility

Fig 4: Fuel Evaporation Control System Function Diagram (Vehicles With Through-Loading Facility)

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

B. Function

Regeneration takes place provided the following conditions exist:

coolant temperature <70°C
<2 minutes after starting engine
engine not in deceleration mode.

A fuel evaporation control system is installed so that fuel vapors pass to atmosphere. The fuel vapors stored in the activated charcoal filter are drawn off at coolant temperatures >70°C through the regeneration switchover valve (Y58/1, engine 120 Y58/2 and Y58/3) and combusted in the engine (not in deceleration mode).

Y58/3 Right regeneration switchover valve

Arrow Regeneration switchover valve coupling

Fig 5: Identifying Right Regeneration Switchover Valve And Regeneration Switchover Valve Coupling

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.

To control the quantity regenerated, the regeneration switchover valve is actuated (pulsed) with a frequency of 7 1/2 Hz by the LH control unit (N3/1, engine 120 N3/2 and N3/3). The regeneration quantity is determined by the constant opening and closing of the switchover valve in on and off times of various length.

The cross section in the switchover valve is altered as a function of the intake manifold vacuum by the diaphragm-guided valve needle.

Testing fuel evaporation control system, see Diagnosis Manual Engine, Volume 2 LH Gasoline Injection System.

Regeneration switchover valve (Y58/1, engine 120 Y58/2 and Y58/3), de-energized closed.

Valve plate opened.

Fig 6: Function Of Regeneration Switchover Valve

Courtesy of MERCEDES-BENZ OF NORTH AMERICA.