Figure 2-77a. EURO-2 gasoline vapor recovery system:
1 - adsorber hose and fuel tank valve;
2 - fuel tank valve;
3 - gas tank valve hose, steam line;
4 - throttle pipe with receiver;
5 - adsorber and throttle hose;
6 - adsorber;
7 - clamp;
8 - bolt;
9 - adsorber mounting bracket;
10 - nut;
11 - steam line and gravity valve hose;
12 - gravity valve;
13 - steam pipe;
14 - fuel tank.
The gasoline vapor recovery system (PVRS) consists of a carbon adsorber 6 (figure 2-77a) with electromagnetic purge valve, valve 2 of the fuel tank, gravity valve 12, steam pipe 13 and hoses 1, 3, 5 and 11.
Gasoline vapors pass through gravity valve 12 and fuel tank valve 2. The gravity valve prevents fuel from leaking out of the tank when the vehicle rolls over, and the fuel tank valve prevents excessive pressure build-up or drop in the fuel tank.
After passing the valves, gasoline vapors enter the adsorber 6, where they are absorbed by activated carbon. The second nipple of the adsorber is connected by hose 5 to the throttle pipe, and the third to the atmosphere. When the engine is off, the electromagnetic valve is closed, in this case, gasoline vapors do not enter the throttle pipe. After starting the engine, the injection system controller begins to send control pulses to the valve. The valve opens and the sorbent is purged: gasoline vapors are discharged through hose 5 and the throttle pipe into the receiver.
Figure 2-77b. EURO-3 gasoline vapor recovery system:
1 - throttle pipe and purge valve hose of the adsorber;
2 - electromagnetic valve for purging the adsorber;
3 - purge valve and adsorber hose;
4 - adsorber;
5 - steam pipe hose;
6 - throttle pipe with receiver;
7 - bolt;
8 - adsorber mounting bracket;
9 - nut;
10 - steam line and adapter hose;
11 - adapter;
12 - adapter and gravity valve hose;
13 - Fuel tank cap with safety valve;
14 - gravity valve;
15 - steam pipe;
16 - fuel tank.