초록 ▼

A two stage exhaust gas recirculation (EGR) valve delivers a wide range of EGR flow while operating with reduced valve actuating forces allowing use of a reduced cost actuator such as a solenoid with smaller sized coil and armature. An attached valve body mounts concentric dual pintle valves includi

A two stage exhaust gas recirculation (EGR) valve delivers a wide range of EGR flow while operating with reduced valve actuating forces allowing use of a reduced cost actuator such as a solenoid with smaller sized coil and armature. An attached valve body mounts concentric dual pintle valves including a larger first valve, which engages a valve seat in the valve body to control exhaust gas flow between inlet and outlet openings and a smaller second valve positioned inside the first valve and engaging a second valve seat in the head of the first valve. The second valve controls a low flow passage inside the first valve. The solenoid armature engages only the smaller second valve during a first stage of its stroke so that the smaller valve is opened first and flow control is maintained in a low flow range. Exhaust and intake differential pressures acting on the second valve are overcome by a smaller armature force because of the smaller area of the second valve. In a second stage of its stroke, the armature also engages the first valve, forcing it off its seat and providing a greater amount of exhaust flow. Opening of the larger first valve requires less force than a single pintle valve because the flow from the open smaller valve reduces the pressure differential in the valve body and thus reduces the force opposing opening of the larger valve.

대표청구항 ▼

1. An EGR valve for controlling exhaust gas recirculation flow in an engine, said valve comprising;a housing enclosing an actuator reciprocable in the housing on an axis; a valve body connected with the housing and defining a valve chamber including axially spaced inlet and outlet openings and a fir

1. An EGR valve for controlling exhaust gas recirculation flow in an engine, said valve comprising;a housing enclosing an actuator reciprocable in the housing on an axis; a valve body connected with the housing and defining a valve chamber including axially spaced inlet and outlet openings and a first valve seat between the openings; first and second pintle valves mounted in the valve body and reciprocable on said axis; said first valve engagable with the first valve seat in the first valve closed position, the first valve including a second valve seat connecting through an internal low flow passage with a connecting opening to the valve chamber; said second valve extending concentrically within the first valve and engagable with the second valve seat in a second valve closed position; and first and second biasing means respectively biasing the first and second valves toward their valve closed positions; said actuator being controllably movable over a total stroke including consecutive first and second stages, the actuator being operative to controllably open the second valve in the first stage of the stroke to allow EGR flow between the valve body inlet and outlet openings only through the low flow passage in the first valve and to controllably open the first valve in the second stage of the stroke to allow flow between the valve body inlet and outlet openings through the valve chamber of the valve body.