Abstract: In an apparatus for controlling the introduction of air into an exhaust pipe of an internal combustion engine in which air is introduced from the intake side to the exhaust side to improve the efficiency of purifying exhaust gases, to prevent a decline in the purification efficiency of a catalyst in a state in which the exhaust gas temperature immediately after starting is low. A control valve 11 is provided in an air introducing pipe 9 for introducing air from the intake side to the exhaust side, and the control valve 11 is set in a shut-off state during starting or during starting and a predetermined time duration immediately after starting.

Abstract: A valve for an automotive vehicle emission system is provided which includes a valve housing with an inlet communicating the valve housing with an air pump; an outlet fluidly communicating the valve with a catalytic converter, the outlet having a check valve preventing flow from an engine exhaust conduit through the valve to the air pump; an upper diaphragm in the valve housing creating a first chamber in the housing which is fluidly exposed to the inlet; a lower diaphragm in the housing creating a second chamber between itself and the first diaphragm, the lower diaphragm forming a third chamber between itself and the housing generally opposite the first chamber; a sealing wall located within the housing separating the second chamber from the inlet, the sealing wall having a surface forming a valve seat with the lower diaphragm, dividing the inlet from the second chamber; a spring urging the lower diaphragm toward the first chamber; and a valve stem connecting the upper and lower diaphragms wherein the air pr

Abstract: In an air-fuel ratio control system for an internal combustion engine, a target air-fuel ratio is set on a side opposite to a direction of deviation of a monitored upstream side air-fuel ratio in such a manner as to counterbalance or offset the deviation of the upstream side air-fuel ratio. The deviation of the upstream side air-fuel ratio may be derived in the form of an mount of a particular component adsorbed in a catalytic converter. A learned value may be used to correct the monitored upstream side air-fuel ratio. Further, a monitored downstream side air-fuel ratio may be used to monitor the setting of the target air-fuel ratio.

Abstract: A catalytic exhaust treatment system for an outboard motor wherein a catalyst bed is supported within the exhaust pipe on a support plate that permits the catalyst bed to expand and contract relative to the surrounding exhaust pipe from which it is spaced. The exhaust gases can flow through the catalyst bed and around the catalyst bed for complete treatment.

Abstract: A need-based method of heating a catalyst in the exhaust-gas system of an internal combustion engine, in which a converting power of the catalyst is determined and the catalyst is heated as a function of the converting power. Depending on the operating conditions of the internal combustion engine, different measures are undertaken for the heating of the catalyst. If the heating measures do not lead to the desired results within a predetermined time interval, a diagnostic function is started. As part of the diagnostic function, particularly effective heating measures are applied. If while using these measures a sufficient converting power of the catalyst is not obtained within a predetermined second time interval, it is assumed that the catalyst is damaged.

Abstract: A catalytic reactor for reducing pollutants in the exhaust gas from an internal combustion engine includes a catalyst element and a heat shield exterior to the catalyst element. The heat shield and catalyst element are mounted within an exhaust pipe so that two annular insulation spaces exist between the catalyst element and the exhaust pipe. The first annular insulation space is located between the interior wall of the exhaust pipe and the exterior wall of the heat shield. The second annular insulation space is located between the interior wall of the heat shield and the catalyst element itself. A spring washer positioned between one end of the catalytic reactor and an axial retaining flange on the exhaust pipe allows the catalytic reactor to expand axially as it heats to operating temperature. A layer of ceramic material may be deposited on the exterior surface of the heat shield to further reduce heat transfer to the exhaust pipe.

Abstract: A catalyst comprising an iridium supported on at least one carrier selected from the group consisting of metal carbides and metal nitrides for eliminating nitrogen oxides in exhaust gas in the presence of oxygen in excess of the stoichiometric quantity of oxidizing components for reducing components. The catalyst is effective for eliminating NO.sub.x in exhaust gas from lean burn engines such as lean burn gasoline engines and diesel engines containing excess O.sub.2 corresponding to an A/F ratio of 17 or over.

Abstract: An oxygen sensor, whose output signal switches between two levels, is arranged in the gas flow leaving the catalytic converter. During regulation at a stabilized speed, the injection time suitable for ensuring stoichiometry of the air/fuel mixture is determined. During a predetermined time interval a time variation of symmetric deviation, whose amplitude and shape is predetermined about a base injection time chosen from the determined injection time, is imposed on the injection time. The base injection time used during successive time intervals is modified progressively and in a monotonic manner so as to center the deviation of the injection time on that of the oxygen storage capacity of the catalytic converter. Catalyst efficiency is evaluated from an oscillation of this signal.

Abstract: An air-fuel ratio control system for an internal combustion engine includes two air-fuel ratio sensors, one upstream of a catalytic converter and the other downstream of the catalytic converter. When an output of the downstream air-fuel ratio sensor has been inverted between rich and lean, a target air-fuel ratio is corrected by a skip amount in a direction opposite to that of the inversion. On the other hand, at no inversion, the target air-fuel ratio is corrected by an integral amount in a direction opposite to deviation of the output of the downstream air-fuel ratio sensor. A fuel injection amount is derived based on a differential between the target air-fuel ratio and an output of the upstream air-fuel ratio sensor. An engine operating condition, the output of the downstream air-fuel ratio sensor or a deterioration degree of the catalytic converter may be used to change the skip amount and the integral amount.

Abstract: An NO.sub.x absorber (18) is arranged in an exhaust passage of an internal combustion engine. The NO.sub.x absorber (18) absorbs the NO.sub.x when the air-fuel ratio of the exhaust gas flowing into the NO.sub.x absorber (18) is lean while releases the absorbed NO.sub.x when the air-fuel ratio of the exhaust gas flowing into the NO.sub.x absorber (18) becomes the stoichiometric air-fuel ratio or rich. An air-fuel ratio sensor (22) is arranged in the exhaust passage downstream of the NO.sub.x absorber (18). When the air-fuel ratio detected by the air-fuel ratio sensor (22) is switched from lean to rich after the air-fuel ratio of the exhaust gas flowing into NO.sub.x absorber (18) is switched from lean to rich, it is decided that the releasing action of NO.sub.x from the NO.sub.x absorber (18) is completed.

Abstract: The invention relates to a diesel internal combustion engine with an exhaust treatment device for the reduction of nitrogen oxides and with a fuel injection system comprising a high-pressure pump and at least one solenoid valve-controlled injection nozzle. The injection nozzle is actuated by an electronic control unit and is intended both for the primary injection, provided for the combustion, and for the additional injection, influencing the effectiveness of the exhaust treatment device. The fuel injection nozzle provided for the primary injection also provides for the secondary injection. The secondary injection takes place as a supplementary injection at the earliest in the region of the end phase of the combustion after the ignition top dead center.

Abstract: The air-fuel ratio control device according to the present invention controls the air-fuel ratio of the engine in accordance with the output of the air-fuel ratio sensor disposed on the exhaust gas passage upstream of the three-way reducing and oxidizing catalyst. Further, to compensate for the change in the output characteristics of the upstream air-fuel ratio sensor, the output of the upstream air-fuel ratio sensor is corrected in accordance with the output of another air-fuel ratio sensor disposed on the exhaust gas passage downstream of the catalyst. Since the response of the downstream air-fuel ratio sensor is delayed due to the O.sub.2 storage capacity of the catalyst, the air-fuel ratio control device in the present invention predicts the future value, by a specified time, of the output of the downstream air-fuel ratio sensor based on the history of the change in the output of the upstream air-fuel ratio sensor and the present output of the downstream air-fuel ratio sensor.

Abstract: An NO.sub.x absorbent (19) which absorbs NO.sub.x when an air-fuel ratio of an inflowing exhaust gas is lean, while releases the absorbed NO.sub.x when lowering an oxygen concentration in the inflowing exhaust gas, is arranged in an exhaust passage of an internal combustion engine. An SO.sub.x absorbent (18) which absorbs SO.sub.x when the air-fuel ratio of the inflowing exhaust gas is lean, while releases the absorbed SO.sub.x when the air-fuel ratio of the inflowing exhaust gas is made rich is arranged in the exhaust passage on the upstream side of the NO.sub.x absorbent (19). When the lean air-fuel mixture is burned, the SO.sub.x is absorbed into the SO.sub.x absorbent (18) and, at the same time, the NO.sub.x is absorbed into the NO.sub.x absorbent (19), and when the air-fuel ratio of the air-fuel mixture is switched from lean to rich, SO.sub.x is released from the SO.sub.x absorbent (18), and NO.sub.x is released from the SO.sub.x absorbent (19 ).

Abstract: An air-fuel ratio control system for an internal combustion engine detects a central value of an output from a first exhaust gas component concentration sensor arranged in an exhaust passage at a location upstream of a catalytic converter and having an output characteristic which is substantially proportional to the concentration of a component in the exhaust gases. The central value is corrected based on the output from the first exhaust gas component concentration sensor, when an output from a second exhaust gas concentration sensor arranged downstream of the catalytic converter falls within a predetermined range. The output from the first exhaust gas component concentration sensor is corrected based on the corrected central value. An air-fuel ratio of a mixture supplied to the engine is corrected based on the corrected output value from the first exhaust gas component concentration sensor.

Abstract: An NO.sub.x absorbent (18) is disposed in an exhaust passage of an internal combustion engine and the exhaust gas is constantly made to circulate through the NO.sub.x absorbent (18) during the operation of the engine. The NO.sub.x absorbent (18) absorbs the NO.sub.x when the air-fuel ratio of the exhaust gas flowing into the NO.sub.x absorbent (18) is lean and releases the absorbed NO.sub.x when the air-fuel ratio of the exhaust gas flowing into the NO.sub.x absorbent (18) becomes the stoichiometric air-fuel ratio or rich. In the majority of the engine operation region, the lean air-fuel mixture is burned in the combustion chamber (3), and the NO.sub.x generated at this time is absorbed into the NO.sub.x absorbent (18). The air-fuel ratio of the exhaust gas flowing into the NO.sub.x absorbent (18) is periodically made the stoichiometric air-fuel ratio or rich, and the NO.sub.x absorbed in the NO.sub.x absorbent (18) is released, and simultaneously reduced.

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: An NO.sub.x absorbent (19) is disposed in an exhaust passage of an internal combustion engine and an NO.sub.x oxidizing agent (18) is disposed in the exhaust passage upstream of the NO.sub.x absorbent (19). The NO.sub.x absorbent (19) absorbs the NO.sub.x when the air-fuel ratio of the exhaust gas flowing into the NO.sub.x absorbent (19) is lean and releases the absorbed NO.sub.x when the air-fuel ratio of the exhaust gas flowing into the NO.sub.x absorbent (19) becomes the stoichiometric air-fuel ratio or rich. When the lean air-fuel mixture is burned, if the temperature of the NO.sub.x absorbent (19) is low, the NO.sub.x oxidized by the NO.sub.x oxidizing agent (18) is absorbed by the NO.sub.x absorbent (19), while if the temperature of the NO.sub.x absorbent (19) is high, the NO.sub.x is oxidized by the NO.sub.x absorbent (19) and absorbed in the NO.sub.x absorbent (19).

Abstract: An exhaust gas-purifying system for an internal combustion engine is provided with hydrocarbon-adsorbing catalyzer for adsorbing unburnt gas components present in exhaust gases. At least one exhaust gas-purifying catalyzer is arranged in the exhaust passage at a location downstream of the hydrocarbon-adsorbing catalyzer. A bypass passage bypasses the hydrocarbon-purifying catalyzer. A changeover valve is arranged in the exhaust passage at a branchpoint between the bypass passage and the exhaust passage, for selecting a first flow path in which exhaust gases are guided to the unburnt gas component-adsorbing catalyzer, or a second flow path in which exhaust gases are guided through the bypass passage. First and second exhaust gas concentration sensors are arranged in the exhaust passage at locations upstream and downstream of the hydrocarbon-purifying catalyzer.

Abstract: A method of feedback control for an electronic fuel injection system in an internal combustion engine includes the steps of calculating a front O.sub.2 sensor switching voltage threshold based on a signal from a front O.sub.2 sensor upstream of a catalyst in an exhaust system for the engine and from a rear O.sub.2 sensor downstream of the catalyst, comparing a voltage output of the front O.sub.2 sensor to the calculated front O.sub.2 sensor switching voltage threshold to determine if a fuel/air ratio of the engine is rich or lean, and decreasing or increasing an amount of fuel to the engine by fuel injectors of the electronic fuel injection system if the fuel/air ratio is determined rich or lean, respectively.

Abstract: A catalytic converter comprises two catalytic matrices 10, 12, 14 mounted in a common housing and spaced from one another by an afterburner chamber 16. An igniter 22 is arranged in the afterburner chamber 16 near the first matrix 12 and a flame guard 18 is arranged upstream of and in close proximity to the igniter 22. The flame guard 18 comprises at least one elongate narrow strip spanning the combustion chamber which acts to spread the base of the flame across the width of the chamber 16 so as to enable the flame to spread in a shorter distance across the exhaust gases before reaching the second matrix 14.