Exhaust gas purifying apparatus

Claim 2

In an exhaust gas purifying apparatus for an externally ignited internal combustion engine operating on fuel continuously injected into its suction tube as primary fuel quantities, said engine having an exhaust conduit, said apparatus being of the known type that has (a) a catalyst situated in said exhaust conduit, (b) a thermal reactor situated in said exhaust conduit upstream of said catalyst and (c) a secondary air pump connected with said thermal reactor for supplying thhe latter with secondary air, the improvements comprising A. An oxygen sonde disposed in said exhaust conduit and emitting signals as a function of the oxygen concentration of the exhaust gases, B. means for supplying said thermal reactor with secondary fuel quantities, C. means coupled to said oxygen sonde for varying said secondary fuel quantities in response to said signals during the warm-up run of said engine when the temperature of said catalyst is above its reaction temperature and D. means for varying said primary fuel quantities in response to said signals during normal operational temperatures of said engine.

Claim 3

An improvement as defined in claim 1, including A. a first movable fuel metering member for varying said primary fuel quantities, B. a first pressurized liquid circuit connected to said first movable fuel metering member for affecting the position thereof as a function of the pressure in said first pressurized liquid circuit, C. a second movable fuel metering member foR varying said secondary fuel quantities, D. a second pressurized liquid circuit connected to said second movable fuel metering member for affecting the position thereof as a function of the pressure in said second pressurized liquid circuit, E. a pressure regulating solenoid valve receiving said signals for operating as a function of said oxygen concentration and for varying the liquid pressure in both said pressurized liquid circuits, F. switching means disposed in said pressurized liquid circuits, said switching means adapted to assume a first position for establishing communication between said first pressurized liquid circuit and said solenoid valve and a second position for establishing communication between said second pressurized liquid circuit and said solenoid valve and G. means coupled to said switching means for moving the latter from said second position into said first position in response to the normal operating temperatures of said engine.

Claim 4

An improvement as defined in claim 2, wherein said switching means is formed of a slider adapted to hydraulically separate said first and second pressurized liquid circuits from one another.

Claim 5

An improvement as defined in claim 2, wherein said pressure regulating solenoid valve is formed as a flat seat valve having a diaphragm as its movable valve member.