Honda Giken Kogyo Kabushiki Kaisha

Masataka Chikamatsu

Takuji Ishioka

Masaki Kanehiro

Shigetaka Kuroda

Shigeru Maruyama

Takashi Hisaki

Kenichi Maeda

Shigeki Baba

Shukoh Terata

Yuichi Shimasaki

Kazutomo Sawamura

Hiroshi Maruyama

Kazuhito Kakimoto

Masayoshi Yamanaka

Hideaki Arai

Yuuichi Shimasaki

Yasunari Seki

Toshihiko Sato

Hisashi Igarashi

Makoto Kobayashi

Takeshi Suzuki

Takuya Aoki

Eitetsu Akiyama

Takayoshi Nakayama

Yoichi Iwata

Tsuyoshi Takizawa

Hajime Uto

Shoichi Nemoto

Katuhiro Kumagai

An abnormality-detecting device for an exhaust gas component concentration sensor arranged in the exhaust system of an internal combustion engine detects abnormality of the exhaust gas component concentration sensor, based on an amount of change in an output from the exhaust gas component concentration sensor exhibited when a predetermined voltage is applied thereto. The abnormality-detecting device defers determination of abnormality of the exhaust gas component concentration sensor until the engine reaches a predetermined operating condition after the engine is started.

Abnormality-detecting device for exhaust gas component concentration

An evaporative fuel-processing system for an internal combustion engine, comprises an evaporative emission control system in which a first control valve is arranged across an evaporative fuel-guiding passage extending between a fuel tank and a canister, a second control valve across a purging passage extending between the canister and the intake system of the engine, and a third control valve at an air inlet port of the canister, respectively. An external diagnostic device is humanly operatable for diagnosing operating conditions of the engine and the vehicle. An ECU is responsive to an output from an external diagnostic device which diagnoses operating conditions of the engine, for determining whether there is an abnormality in the evaporative emission control system, based upon an output from the tank internal pressure sensor, which is obtained when the evaporative emission control system has been brought into the predetermined negatively pressurized state, when the engine is in a predetermined operating condition.

Abnormality diagnostic system for evaporative fuel-processing system of

An evaporative fuel-processing system for an internal combustion engine, incorporates an evaporative emission control system in which a first control valve is arranged across an evaporative fuel-guiding passage extending between a fuel tank and a canister, a second control valve across a purging passage extending between the canister and the intake system of the engine, and a third control valve at an air inlet port of the canister, respectively. An ECU generates operation command signals to the first to third control valves for closing or opening the same to bring the evaporative emission control system into a predetermined negatively pressurized state. The ECU is responsive to an output from a parameter sensor which detects at least one of vehicle speed, temperature within the fuel tank, and an amount of fuel within the fuel tank, for determining whether there is an abnormality in the evaporative emission control system, based upon an output from a tank internal pressure sensor. The output is obtained when the evaporative emission control system has been brought into the predetermined negatively pressurized state, when the value of at least one parameter detected by the parameter sensor falls within a predetermined range.

Evaporative fuel-processing system for internal combustion engines for

An evaporative fuel-processing system includes a first control valve arranged in a charging passage connecting between a fuel tank and a canister for adsorbing evaporative fuel generated from the fuel tank, a second control valve arranged in a purging passage connecting between the canister and an intake passage of the engine, a third control valve arranged in an air inlet port of the canister, and a system internal pressure sensor for detecting pressure within the system. The system is checked for a leak by monitoring a value of the pressure detected by the sensor after the system is negatively pressurized by closing the third control valve and opening the second control valve. The sensor is provided at a location upstream of the first control valve, and the first control valve is closed to detect a value of the pressure or a change thereof. Abnormality determination is carried out based on the detected value of the pressure. Alternatively, all of the above valves are closed in the negatively-pressurized state of the system to detect a first amount of change in the pressure, and then the first control valve alone is opened to detect a second amount of change in the pressure. Abnormality determination can be carried out based on the first and second amounts of change in the pressure, or by comparing a value of the pressure detected when the first and second valves are closed after negative pressurization with a value of the pressure detected after the first control valve is opened.

Evaporative fuel-processing system for internal combustion engines

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.

Misfire-detecting system for internal combustion engines

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.

Fuel supply misfire-detecting system for internal combustion engines

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. Alternatively or in combination, it is determined that the misfire-detecting system is abnormal when the detected sparking voltage has continued to be higher than a third predetermined reference voltage value over a predetermined time period.

A misfire-detecting system for an internal combustion engine detects a value of the sparking voltage generated by the igniting device after generation of the ignition command signal, determines the duration of a discharge of a spark plug, based upon the detected sparking voltage, and determines whether or not a misfire has occurred in the engine, based upon the determined duration of the discharge. For example, the misfire-detecting system measures the duration of the discharge from the time of generation of the ignition command signal, based upon the detected sparking voltage, compares the measured duration of the discharge with a predetermined time period. When the measured duration is shorter than the predetermined time period, it is determined that a misfire has occurred in the engine.

Misfire-detecting system for an internal combustion engine which detects

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. After the changeover has been effected, a time period is measured which elapses from the time the second air-fuel ratio control causes a change in the air-fuel ratio correction value from a richer side to a leaner side or vice versa with respect to a stoichiometric air-fuel ratio to the time the output from the downstream O.sub.2 sensor is inverted from the richer side to the leaner side or vice versa with respect to the stoichiometric air-fuel ratio. It is determined that the catalyst is deteriorated, when the measured time period is shorter than the predetermined time period.

System for determining deterioration of catalysts of internal combustion

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.

Disclosed is an evaporative fuel purging apparatus used for an internal combustion engine. A canister having an absorbing agent for absorbing an evaporative fuel generated in a fuel tank of the internal combustion engine is provided. A drain control valve is provided on a drain port for opening the canister to the atmospheric air, and which is adapted to open and close the drain port. A purge control valve is provided on a purge passage communicating the canister to a part of an intake system, and which is adapted to purge the evaporative fuel absorbed into the canister through opening and closing the purge passage. A diagnostic device diagnoses the presence or absence of leakage in a purge system which is sealed up by closing the drain control valve and the purge control valve after pressure-reduction treatment. In the above apparatus, the drain control valve is opened after termination of the diagnosis by the diagnostic device, to open the canister to the atmospheric air through the drain port, and after an elapse of a specified time, the purge is started by opening the purge control valve. With this construction, it is possible to prevent the rapid change in the air-fuel ratio in re-starting the purge after termination of the diagnosis for the purge system, and hence to improve the stabilization of the emission and the drivability.

Evaporative fuel control unit for internal combustion engine

An evaporative fuel processing system adapted to be capable of detecting abnormality of an evaporative emission control system for storing, in a canister, evaporative fuel generated from a fuel tank for holding fuel to be supplied to an internal combustion engine, and purging evaporative fuel into the intake system of the engine. A first control valve is arranged across a passage extending between the fuel tank and the canister. A second control valve is arranged across a passage extending between the canister and the intake system of the engine. A third control valve is provided for an air inlet port of the canister communicatable with the atmosphere. Through operating these control valves to open and close them, the evaporative emission control system is negatively pressurized, and abnormality of this system is detected based on the pressure detected in this negatively pressurized state thereof. Timing for carrying out abnormality determination is determined depending on conditions of the fuel tank. Before starting the whole process for abnormality diagnosis of the system, evaporative fuel stored in the canister is allowed to be purged for a predetermined time period. When the temperature of fuel in the fuel tank exceeds a predetermined value, the abnormality determination is inhibited.

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.

Control system for internal combustion engines

A tank internal pressure-detecting device for an internal combustion engine having an evaporative emission control system for controlling purging of evaporative fuel generated in a fuel tank thereof into an intake system thereof. An ECU interrupts purging of evaporative fuel by the evaporative emission control system for a predetermined period of time after the engine is started. The ECU causes control valves of the evaporative emission control system to open the interior of the fuel tank to the atmosphere, and stores a value of pressure within the fuel tank detected by a tank internal pressure sensor as a reference value while the purging is being interrupted and at the same time the interior of the fuel tank is opened to the atmosphere. The ECU corrects an output value of the tank internal pressure sensor, based upon the reference value stored.

Tank internal pressure-detecting device for internal combustion engines

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.

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Wako, Japan

Masataka Chikamatsu