Abstract: A gas sensor, e.g. oxygen sensor of the solid electrolyte concentration cell type, having a gas-sensitive element comprising a plate-shaped substrate fixed to an end portion of the sensor body and a laminate of relatively thin layers. A hollow cylindrical protective hood is attached to the sensor body to enclose the sensitive element therein, and two or more openings are formed in the cylindrical wall of the hood to allow a gas subject to measurement to flow into the interior of the hood and flow out. To avoid direct exposure of the sensitive element, which exhibits directionality in its output characteristics with regard to the gas flow through said openings, each of said openings is located between the sensitive element and the free end of the hood such that a cross-sectional plane intersecting the openings does not intersect the sensitive element.

Abstract: The emission level of NOx of a spark-ignition internal combustion engine is lowered by recirculating a relatively large amount of exhaust gases into the combustion chambers of the engine, whereas the emission levels of CO and HC are lowered by controlling the air-fuel ratio of the air-fuel mixture supplied into the combustion chambers at a desired value utilizing feedback techniques in accordance with the composition of the exhaust gases discharged from the combustion chambers.

Abstract: In an automotive internal combustion engine equipped with an exhaust cleaning catalytic converter and a mixture control system to control the richness of the mixture toward a predetermined air-to-fuel ratio that will enable the catalytic converter to produce a maximum conversion efficiency, means are provided to disable the mixture control system and/or reduce the spark advance degrees under low-temperature operating condition of the engine.

Abstract: A method of and apparatus for controlling the air-to-fuel ratio of a combustible mixture in an internal combustion engine of the particular type using mixture control means arranged to regulate the air-to-fuel mixture within a predetermined relatively high range for the purpose of enabling an exhaust cleaning catalytic reactor to perform its maximum function, characterized in that the air-to-fuel ratio is reduced, viz., the mixture is enriched during highly loaded operational conditions of the engine by supplying additional fuel to the mixture supply system of the engine, temporarily disabling the mixture control means during such conditions or diluting the exhaust gases during high load conditions of the engine so that the control means is caused to operate in such a manner as to compensate for the reduced concentration of air in the exhaust gases.

Abstract: A closed loop mixture control system for an internal combustion engine includes a two-barrel carburetor having a primary throttle and a secondary throttle which is adapted to be automatically brought into action when the primary venturi depression reaches a predetermined value. An exhaust composition sensor is provided to control the air-fuel ratio through the primary barrel so that the conversion efficiency of a catalytic convertor is at a maximum during the time prior to the operation of the secondary throttle.

Abstract: The provision of an air-fuel ratio control is made to the secondary side of a twin-barrel carburetor as well as the primary side thereof.

Abstract: A valve closes a fuel passage or an air bleed of a low speed circuit of a carburetor to reduce the amount of air drawn from the low speed circuit into a high speed circuit by a main venturi vacuum higher than an induction passageway vaccum, for example, to zero to prevent an air-fuel mixture provided by the high speed circuit from being excessively leaned.

Abstract: An altitude compensation assembly is incorporated into a conventional carburetor for use with an electronic closed loop air-fuel ratio control system in order to obviate an undesirable enrichment of an air-fuel mixture due to a reduction of air density while a vehicle is operated at higher altitudes.

Abstract: The air-to-fuel ratio of the air-fuel mixture supplied into the combustion chambers of an internal combustion engine can be changed continuously and smoothly to control the air-to-fuel ratio at a required value utilizing a feedback technique is response to the composition of the exhaust gases although a solenoid actuated valve for regulating the fuel amount to prepare the air-fuel mixture is operated in an on and off manner.

Abstract: An internal combustion engine has at the intake system thereof an electronically controlled carburetor operable to control the air-fuel ratio of the air-fuel mixture supplied into combustion chambers of the engine in accordance with the composition of the exhaust gases exhausted from the engine, and at the exhaust system thereof a three-way catalytic converter. The internal combustion engine further has at the intake system thereof a thermostatically controlled air filter system which is designed to keep the air entering the intake system at generally constant temperature.

Abstract: Secondary air is fed into the engine exhaust gas passageway at a position upstream of an oxygen sensor to cause the electric air-fuel ratio control device and the air-fuel mixture generator to provide an air-fuel mixture having an air-fuel ratio lower than a set desired air-fuel ratio during idle and slow speed running of the engine.

Abstract: A two barrel carburetor is disposed in an intake system of an internal combustion engine having a catalytic converter in the exhaust system thereof. One of the barrels is a conventional carburetor barrel, while the other one of the barrels is provided with a fuel nozzle through which fuel is fed into the barrel, the amount of which being controlled by a fuel controller electronically receiving information signals from an exhaust gas composition sensor disposed in the exhaust system at a position upstream of the catalytic converter.

Abstract: The position of a fuel nozzle of a variable size venturi carburetor is adjustable with respect to the venturi orifice in dependence on climatic conditions such as an ambient temperature and/or atmospheric pressure. An additional air delivery passageway controllable by an electronic air/fuel ratio control system in dependence on an exhaust gas sensor signal is connected with the fuel nozzle.

Abstract: A multi cylinder torch ignition internal combustion engine including a main combustion chamber and an auxiliary combustion chamber for each is cylinder designed for proper air-fuel ratios of mixtures for both types of combustion chambers. In order to effectively prevent uneven distribution of air-fuel mixture in each of the engine cylinders irrespective of complicated configuration of the intake manifold of the engine, an intake valve is provided in each of the main combustion chambers and the auxiliary combustion chambers. The latter communicate with the main combustion chambers and have an ignition plug therein. An independent intake passageway is between each intake valve and the intake manifold, and a fuel injection device is disposed in each of the intake passageways. By this arrangement, a proper air-fuel mixture ratio can be individually maintained in the main combustion chamber and the auxiliary combustion chamber.

Abstract: An intake manifold of a multi-cylinder internal combustion engine is constructed so as to feed a rich air-fuel mixture into certain cylinders, and a lean mixture into the others.

Abstract: Herein disclosed is an apparatus by which an exhaust gas sensor is placed in flow communication with the exhaust gases issued from an engine. The apparatus is so constructed and arranged such that a volume of air is maintained about a body portion of the exhaust gas sensor in heat conductive relation with the exhaust gases. The apparatus may be provided with a heater around a probe portion of the exhaust gas sensor which projects into the exhaust conduit. The heater is selectively energized to heat the probe portion when the temperature of the exhaust gases is low.

Abstract: One-half of combustion chambers is fed with a lean air-fuel mixture the ratio of which is above the ratio at which maximum quantities of NO.sub.x are formed and the other half with a rich mixture the ratio of which is below the ratio at which maximum quantities of NO.sub.x are formed, the rich mixture ratio depending on vehicle speed. Above a predetermined load all chambers are fed with a richer-than-stoichiometric mixture and air may be added to the exhaust.

Abstract: A first cylinder of an engine is fed with a relatively rich air-fuel mixture during engine low load operation and with a relatively lean air-fuel mixture during medium and high load operations while a second cylinder of the engine is fed with only a relatively lean air-fuel mixture.

Abstract: A multi cylinder torch ignition internal combustion engine including a main combustion chamber and an auxiliary combustion chamber for each is cylinder designed for proper air-fuel ratios of mixtures for both types of combustion chambers. In order to effectively prevent uneven distribution of air-fuel mixture in each of the engine cylinders irrespective of complicated configuration of the intake manifold of the engine, an intake valve is provided in each of the main combustion chambers and the auxiliary combustion chambers. The latter communicate with the main combustion chambers and have an ignition plug therein. An independent intake passageway is between each intake valve and the intake manifold, and a fuel injection device is disposed in each of the intake passageways. By this arrangement, a proper air-fuel mixture ratio can be individually maintained in the main combustion chamber and the auxiliary combustion chamber.

Abstract: The actual air-fuel ratio of a combustible mixture supplied to an engine is sensed and is compared with a set desired air-fuel ratio which corresponds to a desired ratio of the amount of engine exhaust gases recirculated into the intake system upstream of the carburetor to that of intake air drawn into the engine. An exhaust gas recirculation control valve is operated in dependence on the difference between the actual and desired air-fuel ratios to change the flow of exhaust gases to control the actual ratio of the amount of exhaust gases recirculated into the intake system to that of engine intake air to the desired ratio.