Abstract: A system for converting at least one exhaust-gas component of an exhaust-gas stream of an internal combustion engine is disclosed. The system contains a first device that has a catalytic action and a second device that is positioned downstream of the first device in a direction of flow of the exhaust-gas stream. The second device has at least one electrically heatable first honeycomb body and a second honeycomb body that has at least one coating which at least partly absorbs hydrocarbons, and a third electrically heatable honeycomb body. Three honeycomb bodies are disposed behind each other in the direction of flow of the exhaust-gas stream.

Abstract: A secondary air supply system includes a passage, which supplies the exhaust system of an internal engine with secondary air, an air pump, which supplies secondary air to the exhaust system through the passage, and a valve, which opens and closes the passage. The exhaust system includes an air-fuel ratio sensor for providing information on which abnormality tests are based. In a testing procedure, the air-fuel ratio is monitored under various conditions of the air pump and the value to determine whether the valve has failed to open or close and whether the pump has failed to start or stop.

Abstract: A secondary air introducing path 23 is formed in a cylinder head 1 along an exhaust port 5. Secondary air is fed by an air pump with pressure, and an outlet 23a of the secondary air introducing path 23 is formed so that a blowing direction of the outlet 23a is directed to an exhaust valve 7 side. There is provided a water jacket 22 between the secondary air introducing port 23 and an upper portion of the cylinder head 1.

Abstract: To provide an apparatus for feeding secondary air to exhaust gas in an engine. The apparatus includes a cylinder head having an exhaust port for discharging exhaust gas from a combustion chamber and a secondary air feed passage for feeding secondary air to exhaust gas flowing through the exhaust port. The apparatus is capable of making a length of the secondary air feed passage as short as possible while preventing the permeation of exhaust gas into the secondary air feed passage. This avoids the enlargement of the entire engine, when disposing a reed valve in the engine, since the reed valve is mounted to the cylinder block. A secondary air passage includes a first passage portion extending in a straight line with one end opened toward the inner surface of an exhaust port, toward the downstream side of exhaust gas in the flowing direction.

Abstract: To provide an exhaust secondary air system intended to shorten the length of secondary air feed pipes connected to an exhaust secondary air valve thereby making compact the exhaust secondary air system including the secondary air feed pipes, and also to cool the exhaust secondary air valve and the secondary air feed pipes with running wind. A saddle-type vehicle includes a main frame extending rearwardly from a head pipe; a down frame extending downwardly from the head pipe; an engine disposed under the main frame and behind the down frame; and an exhaust secondary air valve, connected to a secondary air feed pipe, for feeding secondary air to an exhaust passage of the engine via the secondary air feed pipe; wherein the exhaust secondary air-valve is mounted on the down frame.

Abstract: A secondary air supply passage joins a reed valve chamber provided on a cylinder head cover and an exhaust gas port. The secondary air supply passage includes three aligned passages formed in a cylinder head, a cam holder and a cylinder head cover. The secondary air supply passage is formed perpendicular to a cylinder head gasket. One end of the secondary air supply passage opens to a secondary exhaust gas air induction part, formed integrally with a core of the exhaust port, during casting of the cylinder head.

Abstract: An injection valve of a reducing agent metering device is enclosed in a double-walled valve holding element that is connected directly to the exhaust-gas line. It is thereby possible to blow pressurized air into an air gap between an outer wall and an inner wall of the valve holding element and, as a result, to cool at least those parts of the injection valve that are in close vicinity to the exhaust gas.

Abstract: A secondary air injection system for reducing the hydrocarbon emissions of an internal combustion engine that is provided with an air pump supplying air to the exhaust manifold of the engine through a check valve assembly and an elastomeric hose characterized in that a baffle in the shape of a helix is located internally within the hose so as to cause the exhaust pressure waves from the engine and passing beyond the check valve assembly to impinge upon the solid compound surface of the baffle and be divided and diffused as they progress along spiraling paths so as to prevent objectionable noises being generated in the hose by the pressure waves.

Abstract: An exhaust manifold device is provided to allow air to enter an exhaust manifold during normal operation of an engine to prevent exhaust gases being sucked into the cylinders via exhaust valves. Air can be supplied via valves (18 and 21) to the exhaust manifold as required and is supplied to the valve (21) at pressures, above atmospheric pressure, that increase with engine speed.

Abstract: During the warm-up phase of a catalytic converter, the fuel-oxygen ratio in the exhaust gas upstream of the catalytic converter is regulated in dependence on the temperature of the catalytic converter. The amount of fuel is measured on the basis of an injection time into the internal combustion engine. The injection time is calculated from a basic injection time weighted with a weighting factor. The weighting factor depends on the secondary air mass which is delivered to the exhaust gas duct and on a predetermined set value for the fuel-oxygen ratio of the exhaust gas (.DELTA.value) upstream of the catalytic converter. The secondary air mass is regulated in dependence on an engine air intake.

Abstract: An improved anti-coking air injection reaction system in which individual air passages in the engine cylinder head are provided with electrical resistance heating elements that are periodically activated to develop radiant energy that bums off coke deposits formed on the passage side-walls. The heating elements are conveniently implemented with conventional glow plugs. A controller monitors engine operating parameters to identify conditions likely to result in the formation of coke deposits, and schedules activation of the heating elements in relation to the frequency of the identified conditions or the cumulative time of engine operation. The heating elements may be activated sequentially or in banks to reduce electrical loading, and the activation is preferably scheduled during non-critical operating conditions defined by specified ranges of coolant temperature and engine speed and/or load.

Abstract: An engine control system comprising: a mass air flow sensor in an air intake path for a vehicle engine and providing a first input signal indicative of mass air flow through the mass air flow sensor; an air pump unit having an inlet coupled between the mass air flow sensor and the vehicle engine and an outlet coupled in a path of exhaust from the vehicle engine, wherein the air pump unit is responsive to a first control command; a mass air flow estimator responsive to a set of measured engine parameters for providing a second input signal indicative of mass air flow into the intake manifold; and a control unit including a first control command generator responsive to the first and second input signals to provide the first control command responsive to a difference between the first and second input signals, wherein the difference between the first and second input signals represents an estimate of the instantaneous secondary air flow.

Abstract: In an air supply arrangement for an internal combustion engine, particularly for motor vehicles having devices for cooling the engine and for supplying exhaust gas secondary air to the exhaust system of the engine, a single air pump driven by an electric motor is provided for supplying air to the engine cooling system and to the exhaust system and devices for switching the air flow supplied by the air pump to either the engine cooling system or the engine exhaust system are provided. A control unit is also provided which controls the electric motor depending on the amount and pressure of the air needed for the cooling system and the engine exhaust system.

Abstract: An exhaust apparatus for an engine is provided, which is capable of efficiently sucking in secondary air for a catalyst by utilizing an ejector (entraining) effect caused by the exhaust gases and which has a simple and inexpensive structure. Exhaust gases from the engine are introduced into a main muffler body, are expanded and muffled by passage through a plurality of silencer chambers, and are also passed through a catalyst and scrubbed thereby in a state in which they are mixed with secondary air introduced from the exterior. A secondary air introduction pipe for introducing secondary air is provided in a first-stage silencer chamber. A mixing pipe is provided into which are introduced the secondary air introduced from the secondary air introduction pipe and the exhaust gases from the first-stage silencer chamber.

Abstract: An exhaust gas management apparatus including: a first substrate coated with an oxidizing catalyst, wherein the first substrate includes an axial opening and a body portion radially exterior of the axial opening, wherein the axial opening comprises at least part of a bypass passage; an air source located downstream in an exhaust flow path of the axial opening; an air pump unit responsive to a control signal forcing air through the air source wherein, during an activation of the pump unit, the bypass passage is valved shut; and a second substrate coated with an oxidizing catalyst located in the path of exhaust downstream of the first substrate.

Abstract: An internal combustion engine has a cylinder assembly including a cylinder block and a cylinder head mounted thereon, the cylinder assembly having an exhaust passage defined in the cylinder block and a water jacket defined therein around the exhaust passage. A water jacket cover is mounted on an outer surface of the cylinder block in covering relation to the water jacket, and has an opening defined therein. The cylinder block has an air inlet passage defined therein across the water jacket and communicating with the opening and the exhaust passage. A valve cover is mounted on an outer surface of the water jacket cover. The water jacket cover and the valve cover jointly define a valve chamber therebetween. A valve is disposed in the valve chamber for selectively introducing air from the valve chamber through the opening and the air inlet passage into the exhaust passage to assist in burning harmful unburned components contained in an exhaust gas flowing through the exhaust passage.

Abstract: In order to prevent a catalyst for an internal combustion engine from experiencing decreased efficiency by deterioration after long time use of the catalyst, the decreased efficiency of the catalyst is determined, and the internal engine is controlled based on results of the determination so as to maintain high efficiency of the catalyst. The catalyst is installed in an exhaust pipe of the engine. Sensors for detecting conditions of exhaust gas both at a upstream side and a downstream side of the catalyst are provided, respectively. As for the sensor, for example, an oxygen sensor whose output varies stepwise at .lambda.=1, or a sensor whose output varies in proportion to air-fuel ratio can be used. Detected values of the sensors are taken into a control unit, catalyst efficiency and deteriorating degree of the catalyst are estimated by comparison of the detected values, and the engine is controlled so that the catalyst efficiency is maximized.

Abstract: A motorcycle having a secondary air supply for delivering air to the exhaust ports of the engine for assisting in exhaust treatment of the exhaust gases. Air is supplied through reed-type check valves which are positioned in a concealed portion of the motorcycle body for silencing noise. The conduit which connects the check valves to the exhaust ports extends vertically downwardly substantially throughout its length so that condensed liquids in the conduit will pass back to the exhaust port rather than accumulate in the conduit.

Abstract: An apparatus for producing a fresh air stream, has a blower connectable at a pressure side with an exhaust gas conduit of an internal combustion engine of a motor vehicle, a fresh air supply element communicatable with the exhaust gas conduit, a check valve provided between the blower and an opening of the fresh air supply element into the exhaust gas conduit, a cut-off arranged in the fresh air supply element between the check valve and its opening into the exhaust gas conduit and having a closing member loaded with a spring force toward a closing position, an actuating member for the closing member, and a bypass branching from the fresh air supply element so that a pressure which builds when the blower operates and is supplied through the bypass to the actuating member for the closing member acts opposite to the spring force.

Abstract: An exhaust apparatus for a combustion engine having a combustion chamber and an exhaust pipe for conveying exhaust gas in an exhaust stream from the combustion chamber wherein the exhaust apparatus includes a fan member disposed within the exhaust pipe and driven by the exhaust stream so as to create an area of low pressure between the fan member and the combustion chamber whereby extraction of exhaust gas from the combustion chamber is facilitated.

Abstract: An exhaust control system having a plurality of exhaust manifolds is configured and arranged such that combustion of exhaust gases flowing therethrough is unhibited to the extent that the concentration of major pollutants (CO, HC, NO.sub.x) exiting from the tail pipe and into the environment is substantially reduced. The exhaust system utilizes pairs of primary pipes defining an upstream portion of an exhaust manifold which are coupled to exhaust ports whose respective valves provide fluid flow communication to only one of the primary pipes at any moment in time. A secondary pipe defining an downstream portion of the exhaust manifold is coupled to the outlet of the primary pipes through a connector. One-way valves permit atmospheric air surrounding the exhaust manifold to be drawn into each primary pipe proximate its inlet, and into the secondary pipe proximate the connector.

Abstract: Exhaust-gas aftertreatment equipment for an internal combustion engine has a secondary air pump, the delivery pipeline of which discharges into the exhaust system of the internal combustion engine and in which a check valve is disposed. In order to avoid hot exhaust gases flowing back in the event of a defect in the check valve, a heat sensor, which switches the secondary air pump on when a particular temperature is exceeded, is disposed in the air-delivery pipeline. The air, so delivered, mixes with the hot exhaust gases and this mixture is introduced into the exhaust gas system during the negative pressure phases of the exhaust system.

Abstract: An engine exhaust apparatus comprises a sound suppressing section for lowering the exhaust noise level as an exhaust gas discharged from the exhaust port passes through it. The exhaust apparatus is provided with an ejector section for introducing secondary air into the exhaust gas delivered from the sound suppressing section and mixing the gases, and a post-treatment section for purifying the gas mixture delivered from the ejector section. The exhaust gas discharged from an exhaust manifold gets into the ejector section through the sound suppressing section, and is then purified in the post-treatment section. Therefore, the ejector effect cannot be reduced by the sound suppressing section which is subject to high flow resistance. Thus, the exhaust noise level can be lowered with the ejector effect of the introduction of the secondary air improved considerably, and low cost and simple construction can be enjoyed.

Abstract: An exhaust-gas recombustion system for recombusting exhaust gases coming out of exhaust ports of an internal combustion engine equipped with a catalytic converter, comprises a plurality of branch pipes of an exhaust manifold connected to the exhaust ports, a plurality of secondary air injection tubes each connected to either one of the branch pipes for recombusting the exhaust gases coming out of the exhaust ports by secondary air injection. An air-injection nozzle of the secondary air injection tube is directed towards the exhaust port communicating with the connected branch pipe along the axial line of the exhaust port. Additionally, the air-injection nozzle is arranged close to a curved wall of the connected branch pipe to effectively sweep away resultant exhaust gases left in the exhaust port and consequently to assure a rapid activation of the catalytic converter during a cold start of the engine.

Abstract: An exhaust system for an internal combustion engine includes a conduit in fluid communication with a combustion chamber for transferring exhaust gases from the combustion chamber. The exhaust system also includes a port disposed along the conduit for admitting supplemental air into the conduit so that the supplemental air combines with the exhaust gases and flows immediately in a direction downstream from the combustion chamber to draw the exhaust gases from the combustion chamber and to increase combustion of the exhaust gases.

Abstract: A combination valve assembly, particularly for a secondary air blower in internal combustion engines with controlled three-way catalyzer, the combination valve assembly comprises a valve housing having a valve inlet and a valve outlet, a pneumatically actuated valve arranged in the valve housing and having a valve member for locking and releasing a flow path between the valve inlet and the valve outlet, a return valve arranged in the housing downstream of the by-pass valve as considered in a flow direction and having a closing member formed as a leaf spring, a valve plate provided with openings and a stroke catcher limiting an opening stroke arranged so that the leaf spring located between the valve plate and the stroke catcher, a valve closing spring loading the valve member of the valve in a valve closing direction while a differential pressure between a valve inlet pressure and a surrounding pressure loads the valve member of the valve in a valve opening direction.

Abstract: An evaporative emission control system for an internal combustion engine having an exhaust passage, an exhaust secondary air supply system connected to the exhaust passage for supplying secondary air thereto, has an ECU which detects an amount of evaporative fuel generated in a fuel tank, e.g., from an output from a tank internal pressure sensor which detects pressure within the fuel tank. An evaporative fuel passage connects between the fuel tank and the secondary air supply means. A control valve is arranged across the evaporative fuel passage for controlling an amount of the evaporative fuel flowing the evaporative fuel passage. The ECU is responsive to an output from the tank internal pressure sensor for causing the control valve to open when the amount of the evaporative fuel exceeds a predetermined value.

Abstract: An air injection device for attachment to the exhaust manifold of an internal combustion engine is described. A one-way or check valve permits air to be drawn into the air injector to the exhaust manifold when the pressure inside is less than atmospheric to allow more complete burn of unconsumed fuel. On the pressure stroke, the valve closes and prevents untreated exhaust gases from exiting the injector. The valve is designed with mechanisms, such as small protrusions, on the valve and/or on the seat or circumferences that the valve contacts to reduce or prevent sticking of the valve. In one embodiment, the valve may be spherical, and in another embodiment, the air injector may be provided with a mechanism to manually adjust the air flow through the injector.

Abstract: An air injection valve and air discharge manifold for supplying atmospheric air to the exhaust stream of an automotive engine includes an air injection valve for controlling the flow of air, with the valve including a tubular entry section and a unitary tubular exit section. The air discharge manifold includes a socket section for receiving the air injection valve and a conduit section for conducting air to the exhaust stream of the engine. The valve and air discharge manifold are connected by means of male and female rolled threads formed in the valve body and the connector portion of the air discharge manifold.

Abstract: A secondary air supply system for a supercharged engine includes a control valve which controls a diaphragm-operated valve. The control valve with solenoid is electrically controlled according to various engine operating conditions. The diaphragm-operated valve tightly closes the secondary air supply passage to prevent exhaust gas from flowing into the intake passage through the secondary air supply passage under a high engine load and high engine speed condition. The diaphragm-operated valve opens the secondary air supply passage to allow air to be supplied into the exhaust gas under a low engine load and low engine speed condition.

Abstract: An air injection pipe assembly adapted for delivering atmospheric air to the exhaust manifold of vehicle engine comprises a manifold air tube having an inlet and a plurality of spaced outlets. An air inlet valve having an outlet pipe is snugly projected into the manifold air tube and crimped thereto. A plurality of irregularly shaped air injection tubes at their one ends project into the manifold air tube outlets respectively and are brazed thereto and a flair fitting is secured upon the other end of each of the air injection tubes adapted for projection into spaced openings of a vehicle exhaust manifold for securing thereto. The method of making an air injection tube comprises the steps of forming a manifold air tube into U-shape and assembling the outlet of an air valve into one end of the air tube and annularly crimping one end of the manifold tube around the outlet of the air valve.

Abstract: There is disclosed an assembly for mounting on an exhaust manifold of an internal combustion engine to induct air into the exhaust manifold during the low pressure portion of the exhaust pulses of the engine. The assembly includes a stem section adapted to be connected to the exhaust manifold which includes a stem passage. A hollow cylindrical member is connected to the stem section to form a valve chamber which houses an improved valve arrangement. The valve arrangement includes a coiled spring which extends into the valve chamber, a valve seat, and a valve member disc disposed between the coiled spring and the valve seat. The disc is supported by the coiled spring which urges the disc against the valve seat for closing the valve in the absence of manifold pressure. During the negative pressure portions of the exhaust pulse waves, the disc is displaced away from the valve seat for opening the valve and inducting air into the manifold.

Abstract: An improved exhaust gas cleaning system for a multi-cylinder internal combustion engine having an exhaust system with exhaust ports opening into a plurality of combustion chambers. A secondary air supplying system is in communication with the exhaust system for supplying secondary air to the exhaust system. A plurality of reed valve devices are interposed in the secondary air supplying system and are operated to open and close in response to pulsations of exhaust gas developed in the exhaust system during engine operation for controlling supply of secondary air to the respective exhaust ports independently of each other.

Abstract: A secondary air supply system for an engine exhaust system in which the secondary air is drawn to the engine exhaust passage under the suction pressure produced in the exhaust passage. The secondary air supply system includes a non-return valve connected with the engine exhaust passage and an expansion chamber connected with the non-return valve through an elongated connecting passage. The expansion chamber is formed in a casing and the non-return valve is located in a valve chamber formed in the casing and separated from the expansion chamber by a partition wall. The connecting passage is formed by a pipe extending in the expansion chamber from the partition wall.

Abstract: An air valve for an internal combustion engine, said air valve comprising a valve body (10,19), a passage (27) in said body, valve means adapted to normally close said passage (27) to prevent egress therethrough of spent combustion products from said engine and to open on creation of a pressure drop within the engine to permit air to flow through the passage (27) into the engine. The valve means comprises a flexible valve element (18) engageable with a valve seat (26) associated with said passage (27), and means (17,22) for tensioning said flexible valve element (18) to assist effective operation of the valve element (18).

Abstract: Admission of secondary air is effected to remove a portion of exhaust gases staying in components of a secondary air supply system, particularly, a one-way valve with a pair of lead valves. The scavenging with the secondary air is carried out when the fuel supply to the engine is suspended under a predetermined deceleration condition. When the predetermined deceleration condition is satisfied, a secondary air shut off valve is opened even when a coolant temperature of the engine is so high that the secondary air is not required by a catalyst in the exhaust system.

Abstract: A device for introducing air into the exhaust system of a V-type motorcycle engine. The device includes an air manifold advantageously positioned within the V of the engine with passages extending to each exhaust passage adjacent each exhaust port. A control valve run by vacuum admits air to the manifold while reed valves control the passageways to each exhaust passage. The portion of the passage extending through the cylinder head in one embodiment includes a simple bore in tangential intersection with the exhaust passages. A pipe is positioned within the bore which has nozzles therethrough for proper introduction of air to the exhaust.

Abstract: A secondary air supply device for introducing, by utilizing the exhaust gas pulsations, a flow of secondary air into the exhaust gas to after-burn the unburned combustibles comprises a secondary air supply conduit including an inlet section having a reduced flow area and an exit section having an enlarged flow area. This enables an increase of the frequency of resonance of the secondary air supply conduit without reducing the length thereof, so that the amplitude of the pressure pulsation in the secondary air supply conduit is extended to cause the pressure pulsation to occur at least in part in the negative pressure range at a high engine speed, thereby assuring the supply of secondary air even during the high speed operating condition of the engine.

Abstract: A device for controlling the supply of secondary air in an internal combustion engine, having a secondary air control valve and a reed valve provided in the secondary air supply path and having a control circuit for receiving the output signal of an O.sub.2 sensor and producing a control signal for air-bleeding control valves of a carburetor for the engine. The secondary air control valve is controlled in accordance with the opening degree of a throttle valve of the carburetor.

Abstract: An exhaust gas purification apparatus in an internal combustion engine comprising a control device for biasing the air-fuel ratio of the exhaust gas toward the rich side or the lean side from the theoretical perfect air-fuel ratio in accordance with an operating condition of the engine. The control device can include a control valve controlled to open and close according to the output signal of an exhaust gas sensor interposed in a secondary air introducing passage connected to the exhaust passage of the engine upstream of the catalyzer. The control device can also include a device for causing a delay in opening or a delay in closing of the control valve in accordance with the operating condition of the engine.

Abstract: An internal combustion engine having a supercharger utilizes a secondary air supply control system for purifying exhaust gas. A secondary air supply passage with a reservoir chamber is provided in the middle of an intake passage communicating with an exhaust gas passage. A check valve prevents the back flow of exhaust gas in the middle of the secondary air supply passage. The secondary air passage in another embodiment has the intake passage downstream of a compressor or reservoir chamber in communication with the exhaust passage. A suitable amount of air is supplied into the exhaust passage from the intake passage or reservoir, at high pressure via the secondary air passage and check valve.

Abstract: The engine (11) of a stern drive (10) is provided with a vacuum relief valve (28) to relieve any vacuum which may occur in the exhaust manifold (16), thus preventing water from entering the engine through the exhaust system. The relief valve (28) is connected to allow one-way flow from the intake manifold (15) to the exhaust system, thus providing an essentially closed system.

Abstract: An improved internal combustion engine for use with motorcycles including an intake system, an exhaust system, a starting aid such as a choke valve in the intake system for expediting the engine starting, and an exhaust gas cleaning device adapted to supply secondary air to the exhaust system for cleaning the exhaust gas flowing therethrough. The exhaust gas cleaning device comprises a secondary-air supply passage communicated with the exhaust system, a secondary-air control valve gear disposed in the intermediate part of the secondary-air supply passage and adapted to regulate the flow rate of the secondary air flowing through the supply passage, and a controller connected to the valve gear and adapted to close the same on detecting the operation of the starting aid and a vehicle speed below a set value.

Abstract: An improvement in an exhaust gas purification apparatus wherein a detector senses the operation of a device for injecting additional intake air into the intake passage and triggers a timing unit. The timing unit produces a signal for a predetermined amount of time which holds open a control valve for introducing secondary air into the exhaust passage ahead of the catalytic converter. This structure enables the reduction of harmful components of the exhaust gas produced during a gear-change operation of the engine without greatly overheating the catalytic converter.

Abstract: Herein disclosed is a secondary air supply control device for use with an apparatus for purifying an exhaust gas of an internal combustion engine. In the exhaust gas purifying apparatus, a secondary air supply system is made to communicate with the exhaust system of the internal combustion engine so that secondary air may be supplied during the running operation of the internal combustion engine to said exhaust system thereby to oxidize and clear the unburned noxious content of said exhaust system. The secondary air supply control device comprises a vacuum-operated secondary air control valve which is disposed midway of said secondary air supply system for controlling the flow rate of the secondary air to be supplied to said exhaust system; and means for controlling said vacuum-operated secondary air control valve during the deceleration and the choking operation at the start of said engine so that the supply of the secondary air to said exhaust system is interrupted.

Abstract: A secondary air introducing device for an engine including a cylinder, an associated piston, and a secondary air introducing hole formed in a side wall of the cylinder in such a manner that said hole is located near the bottom dead center of the piston and is opened and closed by the piston. The secondary air introducing hole is made to communicates through inlet passages with the atmosphere, so that the external air is introduced into the cylinder through the secondary air introducing hole by a negative pressure which is produced in the cylinder at the end of a suction stroke of said engine, and a control valve means opened and closed according to variations in load of the engine is provided in the inlet passages, thus controlling an amount of air introduced therein.

Abstract: A system for supplying secondary air for an emission control system of an internal combustion engine having a catalytic converter. The system comprises a secondary air conduit communicated with an exhaust port of the engine, a reed valve provided in the secondary air conduit for preventing the counterflow. The inlet of the reed valve is communicated with the atmosphere for inducting secondary air into the exhaust passage. A valve is provided for opening the inlet of the reed valve, and a valve actuator for actuating the valve. An engine temperature sensor is provided for producing an output signal when the temperature of the engine is below than a predetermined temperature. An electric circuit is operated in response to the output signal of the engine temperature sensor.

Abstract: An exhaust gas cleaning device for internal combustion engines, comprising an exhaust system having an exhaust port, a secondary air supply system having an upstream secondary air supply passage communicating with the atmosphere and a downstream secondary air supply passage communicating with the exhaust port for supplying the exhaust system with secondary air, and a reed valve device disposed in the secondary air supply system and adapted to open and close in response to the pulsations of the exhaust gas pressure in the exhaust system. The reed valve device includes a valve housing constituted by a housing structure formed on the cylinder head cover of the engine and a cover member secured to the housing structure, the cover member having a plurality of projections projecting inwardly from the inner surface thereof. The reed valve device also includes a reed valve member clampingly held between the upper surface of the housing structure and the projections of the cover member.

Abstract: An exhaust gas cleaning system for an internal combustion engine having an exhaust system leading to an exhaust port of an engine body. The exhaust gas cleaning system comprises a TWC catalyst disposed in the exhaust system for simultaneously cleaning HC, CO and NO.sub.X in exhaust gas flowing through the exhaust system. A secondary-air supply passage is connected to the exhaust system on the upstream side of the TWC catalyst and coupled to the atmosphere.

Abstract: An exhaust gas cleaning system for an internal combustion engine is provided which has an exhaust system including a TWC catalyst. The exhaust gas cleaning system comprises a secondary air supply passage coupled to the exhaust system on the upstream side of the ternary catalyst for supplying secondary air to the exhaust system. A secondary air control valve is positioned in the secondary air supply passage for regulating the flow of secondary air therethrough. The secondary air control valve comprises a unitary valve casing, a valve passage in the valve casing coupled to the secondary air supply passage, and first and second control valves for separately opening and closing the valve passages. The first control valve is closed when the engine is decelerating and the second control valve is closed when the engine is accelerating or operating at high speed, thereby maintaining the TWC catalyst as a reducing atmosphere.