Abstract: An air management valve in the exhaust emission control system for the engine of an automotive vehicle is operative to selectively control secondary air flow to the exhaust manifold next adjacent to the exhaust ports of the engine, to the center of a dual bed catalytic converter and to the atmosphere.

Abstract: An improved by-pass valve (1) for use in the exhaust system of an internal combustion engine has control means (69) responsive to engine vacuum for exposing a chamber (27) to engine vacuum. The control means is responsive to an abrupt change in engine vacuum such as occurs during engine decelerations for spoiling the vacuum in the chamber and causing a vacuum responsive means (19) to close a first valve (15) and open a second valve (17). The control means reestablishes the vacuum in the chamber after a predetermined time interval causing the vacuum responsive means to open the first valve and close the second valve. The controlled opening and closing of the first and second valves prevents engine backfires. Means (117) overrides operation of the control means when engine temperature reaches a predetermined value whereby the vacuum responsive means maintains the first valve closed and the second valve open.

Abstract: A fluid control system for cleaning exhaust gases of an internal combustion engine by injecting additional air into the exhaust manifold of the downstream of the combustion chamber of the engine according to the engine operating conditions. This system includes a vacuum control valve which supplies vacuum on-off signals to a flow control valve device which meters injecting of additional air.

Abstract: A valve controlling the rate of air flow from a supply pump to an engine exhaust system directs the air flow to the exhaust system through an orifice in a diaphragm valve which is associated with a valve seat separating the air supply from an excess air discharge port. The pressures acting on the diaphragm displace the diaphragm from the valve seat the amount necessary for the rate of air flow through the orifice to the exhaust system to be proportional to the rate of exhaust flow through the exhaust system and for the excess air flow supplied by the pump to be discharged through the excess air port.

Abstract: An exhaust gas purifying system for an automobile engine including at least first and second engine cylinder has a shutter valve for interrupting the supply of a combustible air-fuel mixture to the first engine cylinder during a particular engine operating condition, a three-way electromagnetically operated valve for controlling the operation of the shutter valve, and a secondary air supply unit including a switching valve for selectively supplying a secondary air to a portion of an exhaust passage upstream of at least one catalyst unit disposed in the exhaust passage.

Abstract: An electric air control switching valve for use in controlling the delivery of secondary air from an engine driven air pump selectively, as a function of both engine operation and the operation of its associated emission control system, to either the exhaust manifold of an engine, preferably at a location closely adjacent to the exhaust ports of the engine, during low temperature engine operation, to the atmosphere, as at the dirty side of the air cleaner associated with the induction system of the engine, during low temperature engine deceleration, to a converter in the exhaust system for the engine downstream of the exhaust manifold during normal engine operation, or again to the atmosphere, as at the dirty side of the air cleaner, when the converter temperature exceeds a predetermined temperature.

Abstract: A control valve is mounted on an air relief line branched off from a secondary air supply line extending from an air pump to an exhaust pipe for controlling the pressure of air in the secondary air supply line. The control valve so controls the pressure of the air in the air supply line as to increase it when acceleration of an engine starts or to decrease it when deceleration of the engine starts, whereby the amount of the secondary air supplied to the exhaust pipe is controlled in response to the acceleration and deceleration of the engine.

Abstract: An internal combustion engine having an exhaust system is shown provided with an air pump which is effective for supplying air to the exhaust system to oxidize unburned hydrocarbons within the exhaust gases of the exhaust system; a valve assembly, operatively interposed between the air pump and the exhaust system, is effective, in response to parameters of engine operation, to at times cause a portion or even all of the air supplied by the air pump to be delivered to the atmosphere instead of to the exhaust system.

Abstract: This application discloses a secondary air control system in an internal combustion engine.

Abstract: A control unit having a plurality of pneumatically operated valve constructions for controlling the fluid flow from a first fluid source in relation to the condition of a second fluid source that is adapted to be inter-connected to the pneumatically operated valve constructions, the control unit having a self-contained housing structure carrying the valve constructions therein in substantially a circular array and having a centrally arranged inlet substantially concentric to the circular array and being adapted to be interconnected to the first fluid source.

Abstract: A compound valve device comprises a body member, a first valve member being located in the body member and controlling the fluid communication between a first input port and a first output port, and a second valve member being located in the body member and controlling the fluid communication between a second input port and a second output port. The two valve members operate in sequence, without a significant difference in time in response to one signal pressure.

Abstract: An apparatus for controlling the amount of secondary air fed into an internal combustion engine includes means for controlling the response speed of a secondary air flow control means in accordance with the amount of exhaust gas emitted from the engine. Thus, the equivalent air-fuel ratio can be correctly controlled, without delay, in response to changes in the operating condition of the engine.

Abstract: An engine exhaust gas purification system has a secondary air system for supplying secondary air into the engine exhaust system. The secondary air system has an air metering valve and a switching valve. The air metering valve is operative to meter the secondary air supply in accordance with signals emitted by an air-fuel ratio sensor disposed in the exhaust system to detect the oxygen content of engine exhaust gases. The switching valve is disposed in the secondary air supply line downstream of the air metering valve to interrupt the supply of the secondary air into the exhaust system during a high load engine operation for thereby preventing the exhaust system and, particularly, the catalyst device therein from being overheated. The force to close the switching valve is strong enough to keep the valve closed against the counter-flow of engine exhaust gases from engine exhaust system back into the secondary air system.

Abstract: An engine exhaust gas purification system includes an EGR line for the recirculation of exhaust gases from an engine exhaust system back into an intake system thereof. An EGR valve is provided in the EGR line to control the rate of EGR. The EGR valve is actuated by an actuator which is operated by pressurized air supplied by a diaphragm pump driven by the engine in proportion to the engine speed. The pressure of the pressurized air is substantially proportional to the engine speed, whereby the EGR rate is controlled so as to be substantially proportional to the engine speed.

Abstract: In an exhaust gas cleaning system wherein secondary air is supplied into the exhaust passage to re-burn the unburnt harmful component in the exhaust gases, a secondary air controlling apparatus for an internal combustion engine is provided. At deceleration of the vehicle, secondary air is interrupted from being fed into the exhaust passage, and is introduced into the intake passage to prevent after-burning in the exhaust cleaning system. When the ignition key is switched off, secondary air is fed into the intake passage to prevent the unburnt gas from flowing out into the exhaust passage. This effect is attained by using a valve operated in response to the negative pressure in the intake pipe to protect the exhaust gases cleaning system and to clean the exhaust gases.

Abstract: A by-pass valve (1) for use in the exhaust system of an internal combustion engine has an improvement comprising control means (69) responsive to engine vacuum for exposing a chamber (27) to engine vacuum, the control means being responsive to an abrupt change in engine vacuum such as occurs during engine decelerations for spoiling the vacuum in the chamber and causing a vacuum responsive means (19) to close a first valve (15) and open a second valve (17). The control means reestablishes the vacuum in the chamber after a predetermined time interval and causes the vacuum responsive means to open the first valve and close the second valve, the controlled closing and opening of the first and second valves preventing engine backfires. The control means includes second means (117) responsive to engine vacuum for spoiling the vacuum in the chamber so long as engine vacuum exceeds a predetermined level whereby the first valve is kept closed and the second valve is kept open by the first vacuum responsive means.

Abstract: A by-pass valve (1) for use in the exhaust system of an internal combustion engine has an improvement comprising control means (69) responsive to engine vacuum for exposing a chamber (27) to engine vacuum, the control means being responsive to an abrupt change in engine vacuum such as occurs during engine decelerations for spoiling the vacuum in the chamber and causing a vacuum responsive means (19) to close a first valve (15) and open a second valve (17). The control means reestablishes the vacuum in the chamber after a predetermined time interval and causes the vacuum responsive means to open the first valve and close the second valve, the controlled opening and closing of the first and second valves preventing engine backfires.

Abstract: A diaphragm operated valve bleeds air to the induction passage of a turbocharged engine when the pressure increase across the turbocharger compressor exceeds the particularly high value occurring as the engine throttle is moved from a wide open position; the additional air leans the air-fuel mixture delivered to the engine and thereby prevents a brief pulse of engine power which might otherwise occur, minimizes emission of exhaust gas hydrocarbons and carbon monoxide, and avoids exhaust system backfire noise.

Abstract: A secondary air supply control apparatus for an internal combustion engine comprises an air pump for producing the secondary air flow, a secondary air supply passage leading to an exhaust system of the engine, a bypass passage leading to the atmosphere, and a valve element connected to a diaphragm. The diaphragm constitutes one wall of a pressure chamber which is supplied with a negative intake pressure prevailing in an intake system of the engine, so as to move the valve element to a position at which the secondary air flow is directed to the secondary air supply passage when the negative intake pressure is higher than a predetermined level.

Abstract: An improved by-pass valve (1) for use in an automobile exhaust system (ES) comprises an air inlet (7) connected to an air pump (AP), first and second air outlets (15,23) respectively connected to first and second portions (P1,P2) of a catalytic converter (CC) and a third outlet (33) through which air is dumped to atmosphere. Air is directed from the inlet to the first outlet when engine temperature is less than a predetermined value and from the inlet to the second outlet when engine temperature reaches the predetermined value. A first and normally closed valve (81) is intermediate the air inlet and the first and second outlets and a second and normally open valve (83) is intermediate the air inlet and the third outlet. The first valve is opened and the second valve closed when engine vacuum exceeds a predetermined level so air flows to either the first or second outlet. The second valve is reopened whenever the outlet to which air is directed is blocked so air is dumped to atmosphere.

Abstract: An engine system of the invention comprises an internal combustion engine; a carburetor; an exhaust gas recirculation system; an exhaust gas treatment device; and a source of secondary air, in which there is provided a fluid network which interconnects the source of secondary air, the engine exhaust system at a position upstream of the exhaust gas treatment device and the exhaust gas recirculation system at a position upstream of an exhaust gas recirculation valve and there is also provided an air injection control valve fluidly disposed in the fluid network intermediate the source of secondary air and the exhaust gas recirculation system. The air injection control valve is adapted to selectively permit and prevent the admission of air to the exhaust gas recirculation system.

Abstract: An exhaust gas control actuator wherein the feed of secondary air fed to an exhaust piping is controlled by an oxygen concentration detector disposed in the stream of exhaust gas of an internal combustion engine and an air-fuel ratio of the exhaust gas entering a catalyst disposed downstream of the exhaust piping is maintained within a given range. The actuator comprises a flow control valve and a flow control device for controlling the flow control valve. The flow control valve is provided with a flow-in port communicated with an air pump and the valve body, a flow-out port communicated with an exhaust manifold and a bypass port communicated with an air cleaner.

Abstract: A control unit having a plurality of pneumatically operated valve constructions for controlling the fluid flow from a first fluid source in relation to the condition of a second fluid source that is adapted to be interconnected to the pneumatically operated valve constructions, the control unit having a self-contained housing structure carrying the valve constructions therein in substantially a circular array and having a centrally arranged inlet substantially concentric to the circular array and being adapted to be interconnected to the first fluid source.

Abstract: An exhaust gas purifying apparatus for internal combustion engine of the type having an intake conduit for supplying air-fuel mixture to the engine, an exhaust conduit for conducting exhaust gas discharged from the engine to a catalyst for purifying the exhaust gas, secondary air supply pump driven by the engine for supplying secondary air to the exhaust conduit and detector for detecting oxygen content of the exhaust gas. The negative pressure in the intake conduit is compared with the differential pressure produced across a restriction disposed in the secondary air supply conduit thereby to control the quantity of the secondary air supply so as to be proportional to the quantity of the intake in dependence on the result of the comparison. The output signal of the oxygen detector is utilized for modifying the above control.

Abstract: An exhaust gas purifying system of the type utilizing a three-way catalyst containing an oxygen storage material includes an electronic control unit for controlling the amount of secondary air supplied to the exhaust system of an internal combustion engine. The electronic control unit receives a signal from an exhaust air-fuel ratio sensor indicative of an air-fuel ratio of the exhaust gases and provides a pulse signal to an electromagnetic valve disposed in the passage of the secondary air leading to the upstream of the three-way catalyst. The amount of secondary air supplied to the exhaust system is controlled such that the resultant exhaust gases having an exhaust air-fuel ratio greater than the stoichiometric ratio and those having an exhaust air-fuel ratio smaller than the stoichiometric ratio are alternately supplied to the three-way catalyst thereby to achieve the average exhaust air-fuel ratio to fall within the optimum purifying conditions of the three-way catalyst.

Abstract: An exhuast gas purifying apparatus for use in an automobile multi-cylinder engine of the type which has exhaust ports communicating with engine cylinders and through which exhaust gases are emitted subsequent to combustion of an air-fuel mixture. The exhaust gas purifying apparatus comprising a reducing catalyst unit and a three-way catalyst unit which are disposed in a main exhaust manifold which is connected at one end to a first group of the exhaust ports and at the other end to the atmosphere, and an auxiliary exhaust manifold connected at one end to a second group of the exhaust ports and at the other end to a portion of the main exhaust manifold at a location downstream of the reducing catalyst unit and upstream from the three-way catalyst unit. A pressure operated valve is disposed in a secondary air supply passage for introducing a secondary air into the auxiliary exhaust manifold by the utilization of the pulsating flow of the exhaust gases through the auxiliary exhaust manifold.

Abstract: A secondary air supply system for the exhaust system of an internal combustion engine having a catalytic converter with a three-way catalyst. The system has an air control valve which selectively supplies a part of compressed air to the exhaust system while relieving the rest of the air to the atmosphere. The air control valve has a first valve element which controls a passage between an inlet port and an outlet port and a second valve element which controls a passage between the inlet port and a relief port, the first valve element being controlled by a first diaphragm means in an ON/OFF manner by changing-over of supply of different actuating fluid pressures depending upon monitoring of residual oxygen in exhaust gases, while the second diaphragm element is operated by a second diaphragm means which responds to the duty ratio of changing-over of the different actuating fluid pressures so as to compensate for the change of mean flow of secondary air.

Abstract: An apparatus for controlling the amount of secondary air injection including a secondary air injection system which allows the injection of secondary air into an exhaust system for the purpose of causing the combustion of unburned components of the exhaust gas from an internal combustion engine, an air to fuel ratio sensor which determines either the concentration of the oxygen or the concentration of the carbon monoxide in the exhaust gas, a means which senses a sudden acceleration of the internl combustion engine, a control means which sends out an activating signal in response to the output of the air to fuel ratio sensor and the means for detecting a sudden acceleration of the internal combustion engine and a valve means which controls the amount of secondary air injected by the secondary air injection system in response to the activating signal from the control means whereby the valve means causes the amount of secondary air injected into the secondary air injection system to increase when the air to fue

Abstract: An internal combustion engine has a secondary air supply system and a fuel injection system including a two-fluid injection nozzle operative to inject air and fuel both under pressure into engine intake system. The secondary air supply system includes an air pump and a secondary air supply line extending between the pump and the engine exhaust system. The two-fluid injection nozzle is pneumatically connected to an air distributor provided on the secondary air supply line whereby pressurized air from the air pump is also supplied to the two-fluid injection nozzle and injected thereby together with the fuel to facilitate atomization of the injected fuel as well as to supercharge the engine.

Abstract: Disclosed is a secondary air supplying device of an internal combustion engine having an exhaust passage provided with a catalyzer for purifying exhaust gas. The device includes a first air injection port provided in the exhaust passage at the upstream side of an exhaust manifold and a second air injection port provided in the exhaust passage at the upstream side of the catalyzer. Under the engine warming operating condition only when the engine speed is abruptly accelerated, or during a predetermined time interval after the engine is warmed, is secondary air injected into the exhaust passage from the second air injection port. When the engine is in the other operating conditions, secondary air is injected into the exhaust passage from the first air injection port.

Abstract: A method of operating a three-way catalyst which contains an oxygen storage material and which is mounted on the exhaust system of an internal combustion engine is disclosed. In order to operate the three-way catalyst effectively, the air-fuel ratio of the mixture supplied to the engine is set to be richer than the stoichiometric ratio, and secondary air is intermittently supplied by an air pump into the exhaust system upstream of the three-way catalyst, thereby to alternately vary the air-fuel ratio of the exhaust gases supplied to the three-way catalyst to become rich and lean with respect to the stoichiometric ratio.

Abstract: A secondary air supply system for the exhaust system of an internal combustion engine having a catalytic converter with a three-way catalyst, having an air control valve which selectively supplies a part of compressed air to the exhaust system while relieving the rest of the air to the atmosphere, wherein the air control valve has a valve element balanced by oppositely acting springs to a neutral position where it supplies a predetermined amount of secondary air necessary to provide stoichiometric exhaust gases at a standard flow of exhaust gases and is shifted to opposite sides of the neutral position in accordance with oscillation of feedback control of the air/fuel ratio of exhaust gases, the neutral position being shifted in accordance with changes of the flow of exhaust gases from the standard flow by diaphragm means against the balancing spring force in order to make the neutral position follow the flow of exhaust gases.

Abstract: A system for purifying exhaust gases of engines by first passing the exhaust gases through a 3-way catalyst in a reducing condition, and secondly through an auxiliary catalyst which accelerates at least the oxidizing reaction in an oxidizing condition, wherein the reducing and oxidizing conditions of the exhaust gases are controlled by a programmed supply of secondary air to the exhaust gases at the upstream sides of the two catalysts, the program for the supply of secondary air being predetermined depending upon operational conditions of the engine, such as the rotational speed and the intake manifold vaccum of the engine.

Abstract: In a device for purifying the exhaust gases discharged from an internal combustion engine of the type having a secondary air supply pipe for charging the secondary air from an air source such as an air pump into an exhaust pipe upstream of an exhaust gas reactor or the like, a three-way valve is inserted in the supply pipe in such a manner that the three-way valve may be displaced between a first position at which the air source and the exhaust pipe are communicated with each other and a second position at which the communication between them is interrupted and the secondary air is relieved or returned to the air source bypassing the exhaust pipe; an air-fuel ratio sensor is inserted into the exhaust pipe downstream of the opening of the secondary air supply pipe into the exhaust pipe; and means for controlling the three-way valve is provided so that when the air-fuel ratio detected by the sensor is lower than a reference or optimum ratio at which the best performance of the reactor is expected the three-way

Abstract: In a system for delivering secondary air from an air pump selectively, as a function of engine operation, to either the exhaust manifold at a location closely adjacent to the exhaust ports of the engine, or either to a converter in the exhaust system downstream of the exhaust manifold or to the atmosphere, as preselected, an integral air switching diverter valve assembly having an inlet connected to the air pump, a primary outlet for discharge of air to the exhaust manifold and a secondary outlet, for delivery of air either to the converter or to the atmosphere, as preselected, a valve being mounted in the assembly for movement between a first position to which it is normally biased to allow secondary air flow and through the secondary outlet while blocking secondary air flow through the first outlet to the exhaust manifold and a second position to allow secondary air flow to the exhaust manifold while blocking air flow out through the second outlet, the assembly including a differential pressure operated swi

Abstract: An air switching valve for controlling supply of secondary air to an exhaust system of an engine closes an air release port thereof to increase an amount of secondary air to be supplied at least at an initial stage of an engine acceleration operation. The air switching valve closes a secondary air supply line to stop the supply of the secondary when the engine acceleration operation continues for more than a predetermined time period, thus to prevent an exhaust gas purifier disposed in the exhaust system from over-heat.

Abstract: The exhaust gas purification device includes an exhaust manifold, a purification cylinder connected with the exhaust manifold through a first honey-comb shaped catalyst, and a second honey-comb shaped catalyst positioned at the rear portion of the purification cylinder. Each catalyst is supported by steel wool rings including coarse and dense portions of steel wool. The purification device further includes a secondary air supplying arrangement.

Abstract: Control of secondary air flow to a reactor during normal operating condition of an engine is provided by relieving a predetermined portion of the secondary air discharged from an air pump to a point intermediate the reactor and a muffler installed downstream of the reactor. When the engine is operating under heavy load and/or at high speeds, all of the secondary air from the air pump is supplied to the reactor, while when the engine is operating at full load all of the secondary air from the air pump is relieved to the ambient atmosphere.

Abstract: The secondary air supply system of an internal combustion engine is provided with two reed valves through which atmospheric air is induced to the exhaust system of the engine. The two reed valves are selectively maintained operable under low and high engine speed operating conditions, respectively.

Abstract: Disclosed is an apparatus for controlling the amount of secondary air fed into an internal combustion engine. The apparatus includes an independent means for rapidly applying an absolute pressure signal to a secondary air flow control means, so that secondary air is rapidly supplied into the engine when the secondary air flow control means is being reset in its initial position, and then, next, a rich signal is applied. Thus, the equivalent air-fuel ratio can be correctly controlled, without delay, in response to changes in the operating condition of the engine.

Abstract: A forced air control valve for an air injection system in an internal combustion engine is shifted during cold engine operation to divert air flow to the exhaust manifold upstream of a catalytic converter bed to supply air to the exhaust gases for further combustion prior to entry in the catalytic converter. A diaphragm operated main valve is responsive to a vacuum from the intake manifold for diverting air to the exhaust manifold and a temperature activated vacuum switch shuts off the vacuum when the engine warms up. Upon deceleration during cold engine operation the control valve is shifted to divert air away from the exhaust manifold.

Abstract: A diaphragm operated valve includes a valve body having inlet, outlet and bypass ports in it. A diaphragm assembly includes a flexible diaphragm and a valve stem. The valve stem has a main valve member attached to it which is movable with the diaphragm assembly. The diaphragm is flexibly responsive to negative pressure which regulates main valve member operation. The valve includes a fail safe feature which shuts the main valve passage upon loss of negative pressure. The diaphragm assembly and main valve function to regulate air output from the valve. A second pressure relief valve member is carried by, but operates independently of the valve stem. Means for limiting air output of the main valve during high air input conditions is carried on the pressure relief side of the valve and operates whenever the pressure relief valve is activated so as to aid in the closure of the main valve passage.

Abstract: A forced air control valve for an air injection system in an internal combustion engine has a diaphragm operated main valve member responsive to the vacuum from intake manifold to divert air from the exhaust system to atmosphere. A separate shifting or diverter valve for the exhaust system is temperature responsive and when the main valve member is open permits the supply of air to the exhaust manifold upstream of a catalytic converter only during cold engine operation. During warm engine operation when the main valve member is open, the separate shifting valve diverts the air to the catalytic converter. Upon deceleration during cold engine operation the separate diverter valve is shifted to divert air from the exhaust manifold to the catalytic converter. A temperature sensitive overheat switch is operable upon overheating of the catalyst to vent the forced air to atmosphere.

Abstract: A system for controlling secondary air supply from an engine-driven air pump through a supply line into the engine exhaust manifold has a control valve with air inlet and outlet ports and a slidable, spring-biased valve seat member defining main and auxiliary air release openings. A first valve member is movable by a valve actuator to control the communication between the air inlet and outlet ports and the main air release opening. A second valve member is resiliently urged by a second spring against the valve seat member to control the communication between the auxiliary air release apertures in the valve seat member and the air release port. The valve actuator has first and second air pressure chambers connected to the secondary air supply line upstream of the secondary air control valve. The first control chamber is connected to the engine intake system.

Abstract: A secondary air supply pipe line is opened in the exhaust pipe of an internal combustion engine on the upstream side of an exhaust gas reactor which is mounted in the exhaust pipe, and an air-fuel ratio sensor for detecting the air-fuel ratio of exhaust gases is mounted in the exhaust pipe on the downstream side of the portion where the secondary air supply pipe line is open. An air flow control valve for on-off controlling the flow of air in the secondary air supply pipe line is operated in accordance with the output signal of the air-fuel ratio sensor.

Abstract: An air control valve for use in the exhaust emission control system of an internal combustion engine as used for example, in a vehicle, the air control valve, which is adapted to perform three functions, includes a divert timing switching diaphragm assembly which provides the standard diverter valve function during engine warmup and also controls port air injection during all mid-power conditions, a second diaphragm valve assembly that is operative to provide for secondary air by-pass during high engine load or power operating conditions and, a third diaphragm valve assembly adapted to provide secondary air by-pass during low engine load or vehicle cruise conditions.

Abstract: Disclosed is an air-fuel ratio controlling device of an internal combustion engine having on its exhaust system a three way catalytic converter. The O.sub.2 sensor is disposed in the exhaust system for providing a rich or a lean signal indicating that the total air-fuel ratio is on the rich side or on the lean side of the stoichiometric air-fuel ratio, respectively. A supplementary fuel feed control device having a nozzle flapper mechanism therein is provided for controlling the amount of the supplementary fuel fed into the intake system. This amount of the supplementary fuel is rapidly increased when the total air-fuel ratio is changed from the lean side to the rich side of the stoichiometric air-fuel ratio while the amount of the supplementary fuel is slowly reduced when the total air-fuel ratio is changed from the rich side to the lean side of the stoichiometric air-fuel ratio.

Abstract: Disclosed is a secondary air feed control device in an internal combustion engine having in its exhaust system a three way catalytic converter and an oxygen concentration detector. This detector provides a signal indicating that the total air-fuel ratio is smaller than the stoichiometric air-fuel ratio. The secondary air feed control device comprises a valve port through which the secondary air passes, and an air valve co-operating with the valve port. The air valve is actuated by a pair of diaphragm apparatus. One of the diaphragm apparatus is selectively connected to either the intake manifold or the atmosphere via a restricted opening in response to said signal. The other diaphragm apparatus is selectively connected to either a vacuum source of a constant level or the atmosphere via a restricted opening in response to said signal. The opening speed of the air valve is reduced and the closing speed of the air valve is increased in accordance with the reduction in the level of the load of the engine.

Abstract: Disclosed is an internal combustion engine provided with an exhaust gas recirculation system for recirculating exhaust gas from at least one but not all of the combustion chambers into an intake manifold. This internal combustion engine is also provided with an air injection system for introducing an appropriate amount of secondary air necessary for maintaining an effective exhaust gas recirculation operation. Means are provided for introducing an excessive amount of secondary air into the exhaust system at positions located near the combustion chambers including the chamber from which exhaust gas is recirculated, when the engine is operating under a warming-up condition. Accordingly, a catalytic converter located downstream of the exhaust manifold is rapidly activated just after the starting of the cold engine for oxidizing CO and HC components in the exhaust manifold.

Abstract: Disclosed are an exhaust gas cleaning apparatus of an internal combustion engine, which is provided with a three-way catalytic converter, and an air injection system responsive to the air-fuel ratio of the exhaust gas in the exhaust pipe for increasing or decreasing the amount of secondary air directed to the exhaust pipe so that the air-fuel ratio in the converter is maintained near the stoichiometric value. Means are provided for obtaining a high rate of increase in the introduction of secondary air when the acceleration pump is operated for introducing an amount of excess fuel into the engine during acceleration of the engine. Thus, the air fuel ratio occurring during this condition can be effectively controlled near the stoichiometric value.