Engine air pump pressure/manifold vacuum controlled exhaust gas recirculating control system

Claim 2

An exhaust gas recirculating system, comprising, in combination, an internal combustion engine having an air pump driven by the engine, the air pump producing a supply of air increasing in pressure in proportion to engine speed, and an engine manifold vacuum sensing port, the system comprising, a duct connecting the exhaust gases to the engine intake manifold, a speed and load responsive spring closed valve movable by the differential force between engine manifold vacuum and air pump pressure operatively acting on the valve to open the duct, a servo means for moving the valve, the servo having a flexible diaphragm dividing the servo into a pressure chamber and an ambient air pressure chamber, means connecting the diaphragm to the valve, spring means biasing the diaphragm to a valve closed position, the pressure chamber having a first opening connected to the air pump and a second opening connected to the manifold vacuum port, and flow restricting means in the first and second openings.

Claim 3

A system as in claim 1, the manifold vacuum opening restrictor being of a smaller flow area than the air pump opening restrictor.

Claim 4

An exhaust gas recirculating system, comprising, in combination, an internal combustion engine having an air pump driven by the engine, the air pump producing a supply of air increasing in pressure in proportion to engine speed, the engine having intake and exhaust manifolding and a carburetor with an induction passage connected to the intake manifold and having a manifold vacuum sensing port therein, a duct connecting portions of the intake and exhaust manifolding for recirculating exhauSt gases back into the engine, a valve movable between alternate positions to open and close the duct, and a load and speed sensitive servo connected to the valve for moving the same, the servo having a plunger connected to the valve, and differential force means acting on the plunger to open the duct as a function of the differential in pressure between air pump pressure and manifold vacuum conjointly operatively acting on the plunger in one direction opposed by ambient pressure operatively acting on the plunger in the opposite direction.

Claim 5

An exhaust gas recirculating system, comprising, in combination, an internal combustion engine having an air pump driven by the engine, the air pump producing a supply of air increasing in pressure in proportion to engine speed, the engine having intake and exhaust manifolding and a carburetor with an induction passage connected to the intake manifold and having a manifold vacuum sensing port therein, a duct connecting portions of the intake and exhaust manifolding for recirculating exhauSt gases back into the engine, a valve movable between alternate positions to open and close the duct, and a load and speed sensitive servo connected to the valve for moving the same, the servo having a plunger connected to the valve, and differential force means acting on the plunger to open the duct as a function of the differential in pressure between air pump pressure and manifold vacuum conjointly operatively acting on the plunger in one direction opposed by ambient pressure operatively acting on the plunger in the opposite direction.

Claim 6

A system as in claim 3, including an annular flexible diaphragm member connected to the plunger and separating the ambient pressure force from the differential manifold vacuum and air pressure force.

Claim 7

A system as in claim 4, the diaphragm member defining an ambient air pressure chamber on one side and a differential air pressure and manifold vacuum force chamber on the other side, a pair of conduit means connecting air pump pressure and manifold vacuum separately to the second chamber, and an orifice in each of the conduit means, one of the orifices having a different flow area than the other.