Honda Giken Kogyo Kabushiki Kaisha

Akira Hashimoto

Sachito Fujimoto

Hideo Moriwaki

Kotaro Miyashita

Satoshi Kiso

Yoshiaki Matsuzono

Kazumune Sasaki

Hiroyuki Sugiura

Takashi Isobe

Manabu Niki

Yoshitaka Hibino

Yuzuru Koike

Toshikazu Oketani

Toshikatsu Takanohashi

Shigeto Kashiwabara

Akira Murakami

Yuichiro Tanabe

Kentaro Yokoo

Masaaki Tomii

Mistuo Hashizume

An exhaust emission control system for an internal combustion engine, having a nitrogen oxide removing device provided in an exhaust system of said engine for absorbing nitrogen oxide contained in exhaust gases in an exhaust lean condition. An amount of change per unit time in the sulfur oxide amount absorbed in the nitrogen oxide removing device is estimated according to the air-fuel ratio of an air-fuel mixture supplied to said engine and the operating condition of said engine. The estimated amount of change is accumulated to thereby estimate the sulfur oxide amount absorbed in the nitrogen oxide removing device. The sulfur oxide is removed from the nitrogen oxide removing device when the estimated sulfur oxide amount has reached a set value.

Exhaust emission control system for internal combustion engine

An exhaust emission control system for an internal combustion engine having nitrogen oxides removing device provided in an exhaust system of the engine for removing nitrogen oxides in exhaust gases and an oxygen concentration sensor provided downstream of the nitrogen oxides removing device for detecting the concentration of oxygen in the exhaust gases. Deterioration of the nitrogen oxides removing device is determined on the basis of an output of the oxygen concentration sensor after the air-fuel ratio has been changed from the lean region to a rich region with respect to the stoichiometric ratio. Abnormality of the oxygen concentration sensor is determined on the basis of an output of the oxygen concentration sensor during a period in which the air-fuel ratio is kept in the rich region with respect to the stoichiometric ratio immediately after execution of the deterioration determination of the nitrogen oxides removing device.

An exhaust emission control system for an internal combustion engine, having a nitrogen oxide removing device provided in an exhaust system of the internal combustion engine for absorbing nitrogen oxides contained in exhaust gases in an exhaust lean condition. The exhaust emission control system includes first and second oxygen concentration sensors respectively provided upstream and downstream of the nitrogen oxide removing device for detecting an oxygen concentration in the exhaust gases. The air-fuel ratio of an air-fuel mixture to be supplied to the engine is changed from a lean region to a rich region with respect to a stoichiometric ratio. An amount of reducing components flowing into the nitrogen oxide removing device from the time when an output value from the first oxygen concentration sensor has changed to a value indicative of a rich air-fuel ratio after enrichment of the air-fuel ratio is calculated. Deterioration of the nitrogen oxide removing device is determined according to the calculated amount of reducing components and an output value from the second oxygen concentration sensor.

An exhaust emission control system for an internal combustion engine, having a catalyst provided in an exhaust system of the engine for purifying exhaust gases, and a NOx removing device provided downstream of the catalyst for absorbing NOx contained in the exhaust gases in an exhaust lean condition, is disclosed. A first oxygen concentration sensor is provided between the catalyst and the NOx removing device, and a second oxygen concentration sensor is provided downstream of the NOx removing device. A first time period, which is an elapsed time period from the time the output from the first oxygen concentration sensor has reached a first reference value after switching the air-fuel ratio from the lean region to the rich region, is measured. A second time period, which is an elapsed time period from the time the output from the first oxygen concentration sensor has reached a second reference value corresponding to a richer air-fuel ratio with respect to the first reference value, is measured. It is determined according to the first and second time periods and the output from the second oxygen concentration sensor that the NOx removing devices is normal or deteriorated.

A method and device for diagnosing a vehicle, in which a forced activation signal Sx is supplied to a diagnostic target part through an ECU. A current state of the detected diagnostic target part is compared with a state predicted when the forced activation signal Sx is given to diagnose the diagnostic target part. The forced activation signal Sx when the diagnostic target part is judged to be good, or after a predetermined time has elapsed since issue of the signal Sx was initiated.

Method and device for diagnosis for vehicle

A system for detecting malfunction of a radiator, more precisely a thermostat (shut-off valve) in the engine cooling system. In the system, an estimated coolant temperature CTW is calculated from the temperature condition and operating condition at engine starting. When the estimated coolant temperature CTW has reached a judge malfunction value CTWJUD but the detected coolant temperature TW has not reached a judge normal value TWJUD, the thermostat,is discriminated to have malfunctioned, thereby enabling to detect malfunction of the radiator with high accuracy and high response.

System for detecting malfunction of internal combustion engine radiator

In an exhaust secondary air supply system including an electric air pump and a flow rate control valve disposed in an air supply passage connected to an exhaust passage of an engine, the electric air pump is first driven after the start of the engine, and the flow rate control valve is then opened after a lapse of a predetermined time. At a time after starting the driving of the electric air pump, the abnormality of the electric air pump is detected by comparing a deviation between the current before and after driving of the electric air pump with a predetermined reference value. After opening of the flow rate control valve, the abnormality of the flow rate control valve is detected by comparing the deviation between the current before and after the opening of the flow rate control valve with a predetermined reference value.

Abnormality detecting device for exhaust secondary air supplying system

An evaporative fuel-processing system for an internal combustion engine includes a canister for adsorbing evaporative fuel generated in the fuel tank, a charging passage connecting between the canister and the fuel tank, a purging passage connecting between the canister and the intake system of the engine, an open-to-atmosphere passage for communicating the canister with atmosphere, a charge control valve for selectively opening and closing the charging passage, a purge control valve for selectively opening and closing the purging passage, and a vent shut valve for selectively opening and closing the open-to-atmosphere valve, and a pressure sensor inserted in the charging passage at a location on one side of the charge control valve closer to the fuel tank, for detecting internal pressure within the charging passage. When predetermined conditions are satisfied, the purge control valve is closed and the charge control valve and the vent shut valve are opened. It is determined that the vent shut valve is abnormal when the internal pressure detected by the pressure sensor is below a predetermined negative pressure value while the purge control valve, the charge control valve, and the vent shut valve are in the above respective states.

Evaporative fuel-processing system for internal combustion engines

An evaporative fuel-processing system for an internal combustion engine has an evaporative emission control system. An ECU carries out negative pressurization of the interior of the evaporative emission control system, by opening a purge control valve and closing a vent shut valve, and determines presence/absence of leakage from the evaporative emission control system, based on a rate of decrease in negative pressure within the system, by closing a purge control valve. Before the negative pressurization, the interior of the evaporative emission control system is opened to the atmosphere, and during the open-to-atmosphere, a pressure state within the fuel tank is estimated based on a rate of change in an output from a pressure sensor which senses pressure within the evaporative emission control system. The ECU determines whether the evaporative emission control system is normal, based on the estimated pressure state.

An evaporative fuel-processing system for an internal combustion engine has an evaporative emission control system and a pressure sensor. An ECU carries out negative pressurization of the interior of the evaporative emission control system, by opening a purge control valve and closing a vent shut valve. The purge control valve is closed over a predetermined time period after the interior of the evaporative emission control system is brought into the predetermined negatively pressurized state, and a rate of decrease in negative pressure within the evaporative emission control system is detected. Then, it is determined whether or not there is leakage from the evaporative emission control system, based on the detected rate of decrease in the negative pressure, and at least one detected pressure value at at least one predetermined time point within the predetermined time period over which the purge control valve is closed.

Growing community of inventors

Wako, Japan

Akira Hashimoto