Honda Giken Kogyo Kabushiki Kaisha

Honda Motor Co., Ltd.

Honda Giken Kogyo K.k.

Tsuyoshi Takizawa

Toshihiko Sato

Yoichi Iwata

Takayoshi Nakayama

Yasunari Seki

Hiroshi Ito

Shigetaka Kuroda

Hiroshi Maruyama

Kazutomo Sawamura

Naoki Iida

Shunji Akamatsu

Makoto Kobayashi

Masatoshi Suzuki

Kenichi Maeda

Takuya Aoki

Masataka Chikamatsu

Masayoshi Yamanaka

Yoshihisa Hara

Mamoru Uraki

Shukoh Terata

Yoshiharu Abe

Tetsuya Kaneko

Hajime Uto

Takahiro Kitamura

Yuki Takano

Ryosuke Ibata

Katuhiro Kumagai

A diagnosis apparatus of a fuel supply system includes an operation state detector, an air-fuel ratio sensor, a fuel injection amount calculator, a threshold value table, an abnormality information acquiring device, and an abnormality determining device. In the threshold value table, operation ranges of an internal combustion engine are provided based on an engine speed and a throttle opening. In the threshold value table, a lean side threshold value and a rich side threshold value of an air-fuel ratio correction factor to determine abnormality of the fuel supply system are set beforehand for each of the operation ranges. The abnormality information acquiring device is configured to determine whether the air-fuel ratio correction factor has exceeded the lean side threshold value or the rich side threshold value extracted from the threshold value table according to an operation state so as to acquire abnormality information.

Diagnosis device for fuel supply system

A charge-injected internal combustion engine exhibits improved starting performance with charge-injection timing control. A charge-injected internal combustion engine has an air-fuel injection valve for directly injecting a compressed air-fuel mixture into a combustion chamber. The engine is also provided with an air pump, driven by the crankshaft for discharging compressed air, and a timing controller for setting injection timing of the air-fuel injection valve. When initial startup of the engine is detected, the controller sets the injection timing to the intake stroke. When the engine reaches a predetermined engine speed, or when the pressure of the injection air reaches a threshold pressure where injection of the air-fuel mixture is possible on the compression stroke, the timing controller switches the injection timing from the intake stroke to the compression stroke.

Charge-injected internal combustion engine, and method of operating same

An air-fuel ratio control system for an internal combustion engine controls the air-fuel ratio of a mixture supplied to the engine in response to an output from a first air-fuel ratio sensor arranged in an exhaust passage at a location upstream of a catalyst for purifying exhaust gases emitted from the engine. A control parameter for use in controlling an operation of the engine is changed when deterioration of the catalyst caused by sulfur poisoning is detected to desulfurize the catalyst.

Air-fuel ratio control system for internal combustion engines

A combustion state-detecting system for an internal combustion engine is provided, which detects misfires occurring in the engine. A crank angle sensor generates a crank angle signal with a predetermined period shorter than a firing period of the engine whenever the crankshaft rotates through a predetermined angle. An ECU detects the rotational speed of the engine, based on the crank angle signal whenever the crank angle signal is generated to generate a rotational speed signal, and filters the rotational speed signal to extract a specific frequency component therefrom. A rate of variation in the extracted specific frequency component is calculated every first predetermined time period, and an average value of the rate of variation is calculated every second predetermined time period longer than the first predetermined time period. Further, the difference between the average value and the rate of variation is calculated, and absolute values of the difference is cumulated over the second predetermined time period to obtain a difference cumulative value. Then, the difference cumulative value is compared with a predetermined value, and it is determined that the engine is in a continuous degraded combustion state when the difference cumulative value has continued to exceed the predetermined value, and that the engine is in a sporadic degraded combustion state when the difference cumulative value once exceeds the predetermined value once and then becomes smaller than the predetermined value, before it again exceeds the predetermined value.

Combustion state-detecting system for internal combustion engines

A misfire-detecting system for an internal combustion engine has an ECU which detects a value of a parameter representative of a misfiring state of the engine, and also detects the deterioration degree of a catalytic converter arranged in the engine exhaust system. The ECU sets a misfire-determining reference value, based on the detected deterioration degree of the catalytic converter, compares between the detected value of the above parameter and the misfire-determining reference value, and determines whether the engine is in a misfiring state, based on the result of the comparison.

Misfire-detecting system for internal combustion engines

An air-fuel ratio control system for an internal combustion engine having a catalytic converter arranged in the exhaust system, and an air-fuel ratio sensor arranged upstream of the catalytic converter calculates an air-fuel ratio correction amount by means of proportional control and integral control based on an output from the air-fuel ratio sensor, and controls an air-fuel ratio of a mixture supplied to the engine, based on the air-fuel ratio correction amount. A control frequency at which the air-fuel ratio control is carried out is increased when deterioration of the catalytic converter is detected.

An abnormality-detecting device is provided for an internal combustion engine having first and second oxygen sensors arranged in the exhaust system at locations upstream and downstream of a catalytic converter. An ECU detects the degree of deterioration of the catalytic converter, based on an output from the second oxygen sensor, and sets a reference value for determining an abnormality in the engine, based on the detected degree of deterioration of the catalytic converter. The ECU compares between the set reference value and a value based on an output from the first oxygen sensor, and determines the abnormality in the engine, based on the result of the comparison. Upon detection of the abnormality, an LED is actuated to issue an alarm.

Abnormality-detecting device for internal combustion engines

The air-furl ratio of an air-fuel mixture supplied to an internal combustion engine is controlled in response to an output from at least one oxygen sensor arranged in an exhaust passage for detecting concentration of oxygen present in exhaust gases. The deterioration of the at least one oxygen sensor is detected based on the output therefrom. When the engine is detected to be in a predetermined abnormal operating state, it is not permitted to monitor the output from the oxygen sensor for detecting deterioration thereof.

Oxygen sensor deterioration-detecting device for internal combustion

An air-fuel ratio control system for an internal combustion engine having a catalytic converter arranged in the exhaust system, and first and second air-fuel ratio sensors arranged upstream and downstream of the catalytic converter respectively has an ECU which calculates an air-fuel ratio correction amount, based at least on an output from the first air-fuel ratio sensor, and detects deterioration of the catalytic converter, based on an output from the second air-fuel ratio sensor when the engine is in a predetermined operating condition. The ECU inhibits detection of deterioration of the catalytic converter when the air-fuel ratio correction amount falls outside a predetermined range.

Air-fuel ratio control system for internal combustion engines, having

A catalyst deterioration-detecting system is provided for an internal combustion engine having an oxygen concentration sensor arranged in an exhaust system downstream of a catalyst provided therein. An electronic control unit (ECU) controls the air-fuel ratio of a mixture supplied to the engine in response to an output from the oxygen concentration sensor. The ECU detects a value of an inversion period with which the output from the oxygen concentration sensor is inverted with respect to a predetermined reference value. Operating parameter sensors detect a value of at least one operating parameter of the engine related to a flow rate of the exhaust gases in the exhaust system. The ECU determines whether the catalyst is deteriorated, based on the detected value of the inversion period and the detected value of the at least one operating parameter. The ECU corrects the value of the inversion period in dependence on the detected value of the at least one operating parameter.

Catalyst deterioration-detecting system for internal combustion engines

An air-fuel ratio control system for an internal combustion engine calculates an air-fuel ratio feedback control parameter by proportional-integral control using a proportional factor and an integral factor, based an output signal from a second air-fuel ratio sensor arranged in an exhaust passage at a location upstream of a catalytic converter. An air-fuel ratio correction amount is calculated based on the air-fuel ratio feedback control parameter and an output signal from a first air-fuel ratio sensor arranged in the exhaust passage at a location upstream of the catalytic converter. An inversion period of the output signal from the second air-fuel ratio sensor is measured, and the proportional factor is changed according to the inversion period measured.

An air-fuel ratio sensor deterioration-detecting device for an internal combustion engine having a catalytic converter arranged in the exhaust system, and first and second air-fuel ratio sensors arranged upstream and downstream of the catalytic converter respectively has an ECU which calculates an air-fuel ratio correction amount, based on outputs from the first air-fuel ratio sensors, and detects deterioration of the first air-fuel ratio sensor, based on the output from the first air-fuel ratio sensor. The ECU inhibits detection of deterioration of the first air-fuel ratio sensor when the air-fuel ratio correction amount falls outside a predetermined range.

Air-fuel ratio sensor deterioration-detecting device for internal

An evaporative fuel-processing system for an internal combustion engine, in which a first control valve is arranged across an evaporative fuel-guiding passage extending from a fuel tank to a canister, a second control valve across a purging passage extending from the canister to 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. The ECU is responsive to an output from a tank internal pressure sensor which detects pressure within the fuel tank and the operation command signals, for detecting an abnormality in operation of a predetermined one of the first to third control valves.

Evaporative fuel-processing system for internal combustion engines

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.

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Wako, Japan

Tsuyoshi Takizawa