Abstract: Disclosed herein is an air/fuel ratio controller for an engine, which is equipped with a function to make the air/fuel ratio leaner in a light-load operation zone or the like of a lean burn engine. The controller is intended to improve the starting performance and acceleration feeling of the engine significantly. Upon generation of an acceleration command by a driver during lean burn of the engine at a lean air/fuel ratio, an air/fuel ratio enriching device is operated to set the air/fuel ratio of an air-fuel mixture, which is to be fed to the engine, at a level richer than the lean air/fuel ratio while an actually accelerated state continues in the engine from the time point of generation of the acceleration command.

Abstract: An intake port device comprises an intake port (9) formed by a straight part (13) and a helical part (15), and a valve (17) disposed adjacent to the inlet of the intake port. In order that intake air flow having a large swirl ratio can be supplied to an engine without being encountered with a large resistance even in a light-loaded condition of the engine, the valve (17) is held in its closed position without causing any sharp decrease in the coefficient of intake air flow when closed. In a modification of the intake port device, the valve (17) holds open the lower half of the intake port 9 in its closed position, so that intake air flow having a large swirl ratio can be supplied without being encounted with a large resistance even when the load of the engine is light. In another modification of the intake port device, the free end of the valve (17) is bent and deformed in the downstream direction of intake air so that the flow of intake air may not be encountered with a large resistance.

Abstract: Disclosed herein is an ignition timing controller for a sparing engine. The controller is equipped with a variable swirl forming device for changing over the state of swirling of air, which is flowing into an intake port, in accordance with the operation zone of the engine, so that an optimal control of ignition timing is assured even at the time of malfunction of the variable swirl forming device or during a transition period such as a delay in response by the variable swirl device.

Abstract: A solid electrolyte fuel cell with various improved features has been described. The cell comprises many unit cells each having a structure in which there are laminated a gas-permeable oxygen electrode made from an electron-conducting material, a solid electrolyte consisting of a (CeO.sub.2).sub.1-x (CaO).sub.x (x=0.05 to 0.8) binary system or a third component-containing (CeO.sub.2).sub.1-x (CaO).sub.x (x=0.05 to 0.8) system and a gas-permeable fuel electrode made from an electron-conducting material on a gas-permeable support, many unit cells being connected to each other in series with interconnectors by subjecting end portions of the electrolytes to a masking treatment or the like.

Abstract: A combustion gas sensor and material therefore responsive to changes in the composition of ambient atmospheres wherein the sensing element includes SnO.sub.2 crystals having a mean d of approximately 500-3200 .ANG. and having a surface area to mass ratio S of 1-8 m.sup.2 /g a process for making same. Preferably, the standard deviation of crystal size distribution is 0.2d.

Abstract: An exhaust-gas recirculation (EGR) system has a main control device that supplies a control signal to an EGR valve actuating device that opens an EGR valve to a desired extent. Under normal conditions, a pulse actuating signal having a time-width corresponding to a difference between the actual opening of the EGR valve and the desired opening is supplied to the valve actuating device. Then, the next actuating signal is fed to the valve actuating device after a given length of quiescent time. When the desired opening changes suddenly, however, the normal operation is discontinued and an actuating signal corresponding to a new desired opening is supplied to the valve actuating device. By so doing, the EGR valve is at all times opened to the desired extent, not only under normal conditions but also when the desired amount of valve opening changes suddenly.

Abstract: An idling controller for a variable displacement engine which is capable of operating either in a partial-cylinder or an all-cylinder mode by varying the number of cylinders in operation. When the engine runs at idle, the idling controller assures optimum operation for either cylinder operating mode by varying the quantity of air intake according to the number of cylinders in operation, providing an improvement in both fuel mileage and strating performance, one or the other of which has had to be sacrified conventionally.

Abstract: A multiple cylinder engine of the type which is capable of controlling the number of operating cylinders to operate the engine in either in full or partial displacement mode, wherein the operation is switched smoothly between the full displacement and partial displacement in a simplified manner by detection of the pressure in the intake passage of the engine, putting the engine into full displacement mode by a control pressure when the engine is in cold state preferentially to the pressure in the intake passage, thereby shortening the time period of warming up to achieve smooth operation of the engine quickly.

Abstract: In a multi-cylinder internal combustion engine having a plurality of cylinders which are supplied with air via one common throttle valve and a control unit for regulating the number of operating cylinders which suspends the operation of an arbitrary number of cylinders by intercepting the air supply to said cylinders, it is noted at a point the output of the engine under Z.sub.1 -cylinder operation coincides with the output under Z.sub.2 -cylinder operation at the same degree of opening of the throttle valve at a given constant rate of engine rotation. Based on such a fact, the multi-cylinder internal combustion engine is made capable of shifting to and from Z.sub.1 -cylinder operation and Z.sub.2 -cylinder operation in the proximity of said point where these outputs coincide. This way, there will be no fluctuation in the output nor shock at the time of switching, and the control unit for this purpose can be made simple in construction.

Abstract: A combustion gas sensor and material therefore responsive to changes in the composition of ambient atmospheres wherein the sensing element includes SnO.sub.2 crystals having a means d of approximately 500-3200 .ANG. and having a surface area to mass ratio S of 1-8 m.sup.2 /g a process for making same. Preferably, the standard deviation of crystal size distribution is 0.2d.

Abstract: A process for controlling nitrogen oxides in combustion exhaust gases which comprises adding an oxygen-containing hydrocarbon and/or its precursor to exhaust gases and thereby oxidizing nitric oxide in the exhaust to nitrogen dioxide in the presence of oxygen.

Abstract: A process for removing nitrogen oxide contained in a waste gas is disclosed which includes oxidizing the nitrogen oxide to nitrogen dioxide by mixing the gas with nitric acid vapor in the presence of porous adsorbing agent such as silica gel, colloid earth, alumina, molecular sieves or the like and removing the nitrogen dioxide by absorption with an alkali aqueous solution.