Vaporised fuel recovery system for IC engine e.g. for motor vehicle

摘要

A fuel vapour recovery system for an IC engine collects fuel vapour from the fuel tank and stores it in a canister (8) for subsequent flushing into the inlet manifold. A diagnostic line (5) between the venting line (7) and a point upstream of the throttle valve in the inlet manifold, or to atmosphere, is closed by a control valve (17), the venting line is linked to the inlet manifold by a venting valve (4). By switching the valves and monitoring the pressure in the venting line leaks are easily detected. The pressure monitor (11) is on the venting line or between the fuel tank and the filter. No return valves link the fuel tank and the filter. The leak diagnostic control closes and opens the valves in a set sequence and monitors the changes in pressure with respect to time to determined if there is a leak.