Abstract: A vehicle fuel supply device including a saddle-shaped fuel tank comprised of a main chamber and an auxiliary chamber. A reservoir is disposed within the main chamber. A main pump is provided within the reservoir. A sub-pump is detachably provided within the reservoir. The fuel in the reservoir is drawn up by an operation of the main pump to supply fuel to an engine. A portion of the drawn-up fuel is utilized to generate a negative pressure, the negative pressure is utilized to transfer the fuel in the auxiliary chamber to the reservoir, and the negative pressure is utilized to introduce the fuel in the main chamber into the reservoir.

Abstract: A vehicle fuel supply device including a saddle-shaped fuel tank comprised of a main chamber and an auxiliary chamber. A reservoir is disposed within the main chamber. A main pump is provided within the reservoir. A sub-pump is detachably provided within the reservoir. The fuel in the reservoir is drawn up by an operation of the main pump to supply fuel to an engine. A portion of the drawn-up fuel is utilized to generate a negative pressure, the negative pressure is utilized to transfer the fuel in the auxiliary chamber to the reservoir, and the negative pressure is utilized to introduce the fuel in the main chamber into the reservoir.

Abstract: A high probability of detecting an erroneous misfire occurs when combustion becomes unstable during jolt control. Therefore, during jolt control the reliability of the misfire detection system is degraded. As a result, the misfire detection system is inactivated during jolt control by discontinuing the misfire detection, or by deliberately deeming no misfire has occurred if jolt control has occurred. Alternatively, the misfire detection sensitivity is masked during jolt control.

Abstract: A misfire-detecting system for an internal combustion engine compares detected sparking voltage with a first predetermined comparative level and a second predetermined comparative level lower than the first predetermined comparative level. Whether a misfire has occurred in the engine is determined based upon a logical relationship between results of the comparisons. As a result, a misfire can be detected accurately even when dielectric breakdown of the mixture occurs while a misfire has occurred.

Abstract: A misfire detecting system for an internal combustion engine, including an intake pipe internal pressure detecting device for detecting an internal pressure of an intake pipe of the internal combustion engine, and a misfire detection inhibiting device for inhibiting the detection of misfire when the internal pressure of the intake pipe detected by the intake pipe internal pressure detecting device is lower than an intake pipe internal pressure in a no-load condition.

Abstract: A misfire-detecting system for an internal combustion engine in which a value of sparking voltage is detected, which is generated across a spare plug when high voltage is generated by an ignition device in response to generation of an ignition command signal. When a time period over which the detected value of sparking voltage exceeds a predetermined reference voltage value exceeds a predetermined time period value, the system determines that a misfire has occurred in the engine. A recharging command signal is generated for applying high voltage to the spark plug, after generation of the ignition command signal. As a result, a misfire can be accurately detected.

Abstract: A misfire-detecting system detects a misfire occurring in an internal combustion engine. A value of sparking voltage for discharging a spark plug of the engine is detected. A differentiating circuit differentiates the detected value of the sparking voltage. A misfire-determining circuit compares the differential value of the sparking voltage with a predetermined value, and determines, based upon a result of the comparison, whether a misfire has occurred in the engine.

Abstract: A misfire-detecting system for an internal combustion engine carries out self-diagnosis of the system. In the system, sparking voltage generated across a spark plug of a cylinder of the engine is detected, and the detected sparking voltage is compared with a first predetermined reference voltage value, and a time period is measured over which the detected sparking voltage exceeds the first predetermined reference voltage value. It is determined that a misfire occurred in the engine when the measured time period exceeds a predetermined time period value. It is determined whether the engine is in self-sustaining operation. When it is determined that the engine is in self-sustaining operation, it is determined whether the misfire-detecting system is abnormal. It is determined that the misfire-detecting system is abnormal when the detected sparking voltage is lower than a second reference voltage value.

Abstract: A catalyst deterioration-determining system determines deterioration of a catalyst arranged in the exhaust passage of an internal combustion engine. An ECU is responsive to an output from an O.sub.2 sensor arranged upstream of the catalyst or outputs from O.sub.2 sensors arranged upstream and downstream of the catalyst for controlling the air-fuel ratio of a mixture supplied to the engine by means of an air-fuel ratio correction value (first air-fuel ratio control). When the engine is in a predetermined operating condition, the system effects changeover from the first air-fuel ratio control to a second air-fuel ratio control which is responsive to the output from the downstream O.sub.2 sensor for controlling the air-fuel ratio of the mixture by means of the air-fuel ratio correction value.

Abstract: A misfire-detecting system for an internal combustion engine detects values of operating parameters of the engine, determines ignition timing of the engine, based upon detected values of operating parameters of the engine to generate an ignition command signal indicative of the determined ignition timing, generates high voltage for causing generation of sparking voltage across a spark plug for discharging the spark plug, according to the ignition command signal, detects a value of the sparking voltage generated across the spark plug when the high voltage is generated, compares the detected value of the sparking voltage with a predetermined reference value, and determines whether or not a misfire has occurred in the engine, based upon results of the comparison. It is determined that the system is abnormal, when it is determined that no misfire has occurred while fuel supply to the engine is being interrupted.

Abstract: A control system for an internal combustion engine determines ignition timing of the engine and generates an ignition command signal to generate high voltage for discharging a spark plug provided for each cylinder of the engine. The control system detects sparking voltage generated across the spark plug when the high voltage is generated. The control system measures a duration over which the sparking voltage across the spark plug exceeds a predetermined reference value, after generation of the ignition command signal. According to a first aspect of the invention, the control system detects combustion roughness based on the duration measured. According to a second aspect of the invention, the control means detects an air-fuel ratio of an air-fuel mixture supplied to the engine, based on the duration measured.

Abstract: A misfire-detecting system detects a misfire occurring in an internal combustion engine. A value of sparking voltage for discharging a spark plug of the engine is detected. The detected value of the sparking voltage is compared with a first predetermined value. A degree to which the detected value of the sparking voltage exceeds the first predetermined value is measured. The measured degree is compared with a second predetermined value. It is determined based upon results of the latter comparison whether or not a misfire occurred in the engine. According to a first aspect of the invention, the second predetermined reference value is set based upon detected values of operating parameters of the engine. According to a second aspect of the invention, the determination of occurrence of a misfire is inhibited when the engine is in a predetermined operating condition.