Air pollution control system for internal combustion engine

Claim 1

AN AIR POLLUTION CONTROL SYSTEM FOR AN INTERNAL COMBUSTION ENGINE WHICH COMPRISES A CATALYST BED DISPOSED IN THE EXHAUST SYSTEM OF THE ENGINE AND COMPRISING ACTIVE CATALYTIC MATERIAL OF THE TYPE CAPABLE OF OXIDATION-REDUCTION CYCLING, AND AIR SUPPLY VALVE MEANS CONNECTED TO THE INTAKE SYSTEM OF THE ENGINE AND RESPONSIVE TO INTAKE MANIFOLD VACUUM SO AS TO BE OPEN DURING THE DECELERATION MODE OF ENGINE OPERATION AND CLOSED DURING THE OTHER MODES OF ENGINE OPERATION, SAID VALVE MEANS SUPPLYING AIR TO THE INTAKE SYSTEM IN EXCESS OF ENGINE COMBUSTION REQUIREMENTS SO AS TO SUPPLY OXYGEN TO THE CATALYST DURING DECELERATION, AND THE CATALYST RELEASING THE OXYGEN FOR CATALYTIC OXIDATION OF EXHAUST INGREDIENTS DURING THE OTHER MODES OF ENGINE OPERATION, SAID VALVE MEANS COMPRISING A VALVE ELEMENT MOVABLE BETWEEN A CLOSED POSITION AND AN OPEN POSITION AND MEANS NORMALLY BIASING THE ELEMENT TO ITS CLOSED POSITION, THE VALVE ELEMENT ATMOSPHERIC AND INTHAT THE PRESSURE DIFFERENTIAL BETWEEN ATMSOPHERIC AND INTAKE MANIFOLD PRESSURES EXERTS A FORCES OPPOSING SAID PRESSURE ING MEANS AND TENDING TO OPEN THE VALVE, SAID PRESSURE DIFFERENTIAL FORCES EXCEEDING THE FORCE OF THE BIASING MEANS TO OPEN THE VALVE WHEN THE INTAKE MANIFOLD VACUUM REACHES A HIGH VALUE DURING DECELERATION, BUT BEING INSUFFICIENT TO MOVE THE ELEMENT FROM ITS CLOSED POSITON DURING OTHER MODES OF ENGINE OPERATION, A PORTION OF THE VALVE ELEMENT BEING MASKED OFF FROM ATMOSPHERIC PRESSURE IN ITS CLOSED POSITION, SAID PORTION BEING EXPOSED TO ATMOSPHERIC PRESSURE WHEN THE VALVE ELEMENT MOVES OUT OF THE CLOSED POSITION TOWARD THE OPEN POSITION SO AS TO INCREASE SAID PRESSURE DIFFERENTIAL FORCE, WHEREBY ONCE THE VALVE IS OPENED AT A HIGH INTAKE MANIFOLD VACUUM DURING DECELERATION IT WILL REMAIN OPEN DURING A SUBSTANTIAL PORTION OF THE DECELERATION CYCLE DESPITE A SUBSTANTIAL REDUCTION OF THE INTAKE MANIFOLD VACUUM.