Fuel supply system for fuel-injected IC engine e.g. of urban vehicles

摘要

The IC engine has a fuel-feed (19) to the fuel injectors and a return fuel-feed (36) back to the fuel tank. The return fuel feed has a first pressure control valve (39) to maintain the normal working pressure of the injectors, and a parallel lower pressure control valve (38) which is opened when the fuel tank venting filter is purged into the inlet manifold. The lower return feed pressure lowers the fuel pressure at the injectors and reduces the fuel injection to compensate for the added fuel vapour in the inlet air. The return valve is mounted close to the inlet manifold before the manifold branches. The lower pressure valve is in line with a shut-off valve (41) electrically operated by a solenoid (42) which is controlled by a signal from an engine-management system. Alternately a variable pressure control valve can be fitted with the pressure set by the purging control.