Abstract: 2-Azetidione derivatives represented by the following formula ##STR1## wherein X is a hydrogen atom, a halogen atom, a lower alkyl group, a lower alkoxy group, a hydroxyl group or a cyano group, l is 1 or 2, R.sup.1 is a lower alkyl group, a cycloalkyl group, a 1-naphthylmethyl group, an optionally substituted phenethyl group, an optionally substituted phenyl group, an optionally substituted benzyl group or a bis(alkoxycarbonyl)ethyl group, and R.sup.2 is a lower alkyl group, a lower alkoxy group, an amino group, an adamantyl group, a lower alkoxycarbonylmethyl group or an optionally substituted phenyl group, are disclosed. These compounds are useful as blood platelet aggregation inhibiting agents.

Abstract: A pump apparatus comprises a pump housing, an impeller having a plurality of radial grooves rotatably disposed within the pump housing, first and second fluid passages each defined by the impeller and the pump housing at both sides of the impeller, a motor having an output shaft for driving the impeller, a first radial clearance between the impeller and the output shaft of the motor, and a second radial clearance between an outer peripheral surface of the impeller and the pump housing, which is smaller than the first clearance.

Abstract: A method for controlling the air-fuel ratio in an internal combustion engine in which the correction of the air-fuel ratio is carried out on the basis of the determination as to whether the base air-fuel ratio is the value in the richer or the leaner side of the air-fuel ratio corresponding to the best specific fuel consumption. A different number of operation points for detecting the signals of the parameters of the engine running state are selected for the automatic constant speed control state and for the non-automatic speed control state.

Abstract: A method for controlling the air-fuel ratio in an internal combustion engine in which the correction of a base air-fuel ratio is carried out on the basis of the determination as to whether the base air-fuel ratio is on the richer or the leaner side of the air-fuel ratio corresponding to optimum specific fuel consumption, the determination being carried out by comparing four driving state indicating signals at different air-fuel ratios with each other, the correction being directed to bringing the base air-fuel ratio closer to the air-fuel ratio corresponding to the optimum specific fuel consumption.

Abstract: A system for controlling the air-fuel ratio in which the amount of fuel injected into the engine is controlled in accordance with the flow rate of air passing through an air intake pipe including a throttle valve for introducing the air into the engine and the engine operating conditions. A bypass of the air intake pipe is opened or closed to change the air-fuel ratio of the mixture to slightly richer and leaner sides of a basic air-fuel ratio, and the change of the engine output conditions based on the change of the air-fuel ratio is used to correct the air-fuel ratio in an optimum direction. On the basis of a parameter indicating the engine operating conditions such as the detection value of the intake pipe pressure, a control is made to introduce the air which passed through the bypass to one of the upstream or downstream portion of the throttle valve.

Abstract: A gas flow measuring apparatus is provided with an air flow sensor mounted in a suction duct upstream from a throttle valve and exposed to the air flow through the suction duct. The air flow sensor includes a ceramic flat plate mounted in the suction duct so that the main surfaces of the ceramic flat plate are parallel with the air flow. First and second temperature-dependent resistor coatings are formed on the main surfaces of the ceramic flat plate so that the first resistor coating and the second resistor coating are respectively formed on the downstream and upstream end portions of the ceramic flat plate by printing or evaporating a platinum. An electric heater coating is formed between the first and second resistor coatings but spaced therefrom to affect only the first resistor coating, and the heater coating is also formed by printing or evaporating a platinum.

Abstract: The timing of spark ignition is set in normal operating conditions at a programed spark advance angle corresponding to the MBT (minimum spark advance for best torque). When knocking of the engine is detected by a vibration sensor, the ignition timing is delayed by a predetermined amount, e.g., 2.DELTA..theta., for each engine cycle that knocking is detected in synchronism with the rotation of the engine. When knocking is not detected, the ignition timing is advanced by another predetermined amount, for each engine cycle that knocking is not detected. e.g., .DELTA..theta.. In this method for controlling the spark timing, the amount of retardation, 2.DELTA..theta., is selected to be larger than the other amount of advance, .DELTA..theta..

Abstract: A spark-ignition timing of the internal combustion engine is normally set at an MBT (minimum spark advance for best torque). However, when a knocking of the engine is detected by a vibration sensor fixed to the engine, the ignition timing is retarded with respect to the MBT by an angle corresponding to either a non-knocking limit retard angle or a maximum retard angle determined by engine operating conditions whichever is smaller.

Abstract: A method of detecting knocking intensity of an internal combustion engine uses a detector for detecting vibration propagated within the engine and a first calculation circuit for obtaining an average value of vibration sensed by the vibration detector within a predetermined crank angle before the top dead center, and in which knocking is identified when the ratio between the above average value and the maximum value of vibration after the top dead center exceeds a predetermined value.

Abstract: A method of controlling the timing of spark ignition for an internal combustion engine by monitoring the magnitude of vibration of the engine caused when the engine is knocking. A vibration sensor is mounted on the engine to detect the magnitude of the engine vibration, and the average value of the magnitude of vibration of the engine prior to the engine piston arriving at the top dead center position is compared with the instantaneous value of the magnitude of vibration of the engine caused after the arrival of the piston at the top dead center position. Consequently, when the instantaneous value of the vibration is greater than the average value of the vibration, the spark timing is retarded to prevent the occurrence of knocking in the engine. To accurately detect knocking in the engine, the average value of the vibration is obtained by dividing the integrated value of the monitored vibration by the monitoring time.

Abstract: A method for controlling the ignition timing for the internal combustion engine is disclosed. When it is decided that the engine load is large on the basis of the engine number of revolutions per minute and intake pressure. If the engine is in the knocking condition, a step lead angle is added to the present lead angle value in the range between a set lead angle and a minimum lead angle. If the engine is not in the knocking condition, on the other hand, a step lead angle is subtracted from the present lead angle value in the above-mentioned range. By contrast, when it is decided that the engine load is small on the basis of the engine r.p.m. and intake pressure. The lead angle control of the present lead angle value is stopped so that the present lead angle is set at the above-mentioned set lead angle or the minimum lead angle value.

Abstract: This specification discloses an exhaust gas cleaning device which is intended for removing harmful substances from exhaust gases of internal combustion engine, especially for removing carbon particles or the like.The device has a body accomodating a filter element adapted to catch the particles in the exhaust gases. The device is attached to the engine as if it were an exhaust manifold so that the clogging particles are conveniently burned by hot gases, whereby the filter element is conveniently recovered.

Abstract: This specification discloses an exhaust gas cleaning device which is intended for removing harmful substances from exhaust gases of internal combustion engine, especially for removing carbon particles or the like.The device has a body accomodating a filter element adapted to catch the particles in the exhaust gases. The device is attached to the engine as if it were an exhaust manifold so that the clogging particles are conveniently burned by hot gases, whereby the filter element is conveniently recovered.