Filter cleaning system for internal combustion engine

Claim 1

A filter cleaning system for an internal combustion engine having an intake manifold and means increasing the pressure of air at the intake manifold during high operation of the engine and for reducing the pressure at the intake manifold during idling operation of the engine said filter cleaning system comprising, a housing having a filter element therein and means direCting air flow through said filter element in a first normal direction, means for periodically directing a blast of air through said filter element in a second direction reverse to the first normal direction of air flow through said filter element to thereby dislodge accumulated dirt from said filter element, said last mentioned means comprising a storage member and valve means connecting said storage member to the intake manifold of said engine to deliver pressurized air through said valve means to said storage member, said valve means including a valve element being spring biased to a closed position whereby the pressure of the air delivered from said intake manifold is not sufficient to open said valve element during idling operation of said engine, a normally closed diaphragm member disposed intermediate said storage member and a port of the housing containing said filter element normally closing said port, means for moving said diaphragm to open said port upon said engine assuming idling operation, said means comprises said diaphragm being subjected to substantially equal forces on each side thereof during high operation of said engine and means for relieving pressure on one side of said diaphragm during idling operation of said engine.