Honda Giken Kogyo Kabushiki Kaisha

Honda Giken Kabushiki Kaisha

Toshikatsu Takanohashi

Teruo Wakashiro

Hiroshi Ohno

Nobuaki Takaoka

Shinichi Kitajima

Kazutomo Sawamura

Hiroshi Kitagawa

Hiroshi Maruyama

Kotaro Miyashita

Masahiro Sakanushi

Akira Hashimoto

Yoshihiko Kobayashi

Hiroaki Muramatsu

Akira Murakami

Yuichiro Tanabe

Hiroshi Oono

Toru Tochizawa

Kenji Sugiura

Mistuo Hashizume

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.

Exhaust emission control system for internal combustion engine

An object of the invention is to reliably judge if a NO absorbent has deteriorated due to sulfur poisoning, or has heat deteriorated. At the time of executing rich spiking, a sulfur poisoning stoichiometric conversion time threshold value tm: LMT-S deterioration, for judging if a NO absorbent has been sulfur poisoned, and a heat deterioration stoichiometric conversion time threshold value tm: LMT heat deterioration, for judging if the NO absorbent has heat deteriorated to an extent that the NO absorption capacity has been lost, are set in relation to the time (stoichiometric conversion time) taken for an output signal from a second O sensor to change from lean to rich. When a measurement value of the stoichiometric conversion time is shorter than the heat deterioration stoichiometric conversion time threshold value tm: LMT heat deterioration, it is judged that the NO absorbent has completely heat deteriorated, and when this is longer than the heat deterioration stoichiometric conversion time threshold value tm: LMT heat deterioration, and shorter than the sulfur poisoning stoichiometric conversion time threshold value tm: LMT-S deterioration, it is judged that there is sulfur poisoning.

Exhaust emission control device for internal combustion engine

An exhaust emission control system for a nitrogen oxide removing device, the control system having a first oxygen concentration sensor provided upstream of the nitrogen oxide removing device, a second oxygen concentration sensor provided downstream of the nitrogen oxide removing device. A first response delay time period from the time when the output value from the first oxygen concentration sensor has changed to a value indicative of a rich air-fuel ratio to the time when the output value from the second oxygen concentration sensor becomes a value indicative of a rich air-fuel ratio is measured. A second response delay time period from the time when the output value from the first oxygen concentration sensor has changed to a value indicative of a lean air-fuel ratio, to the time when the output value from the second oxygen concentration sensor becomes a value indicative of a lean air-fuel ratio is measured. Deterioration of the nitrogen oxide removing device is determined according to the first and second response delay time periods.

In accordance with an output of an oxygen concentration sensor,, an air-fuel ratio correction coefficient KO2 is periodically set to values respectively corresponding to a leaner air-fuel ratio and a richer air-fuel ratio with respect to a theoretical air-fuel ratio (steps S,to S,). Based on an output of an oxygen concentration sensor,, a NOx amount counter nNOx is counted up, and the amount of NOx absorbed by a NOx absorbent catalyst is estimated. When the value of the NOx amount counter nNOx reaches a preset value NSAT, an air-fuel ratio of an air-fuel mixture is set to be further richer than the richer air-fuel ratio.

Air-fuel ratio controlling device for an internal combustion engine

If conditions of stopping an engine are satisfied, it is judged whether the lean operation in which the air-fuel ratio is set to be on a lean side with respect to the theoretical air-fuel ratio is currently performed or not. If the lean operation is currently performed, reduction enrichment of NOx is executed during an enrichment time TRICH, and the engine is thereafter actually stopped.

Exhaust gas purifying apparatus for an internal combustion engine

A system for purifying exhaust gas of an internal combustion engine having a NOx reduction catalyst (NOx absorber) installed in the exhaust system of the engine which absorbs NOx in the exhaust gas generated by the engine in a lean environment where a lean fuel mixture is supplied and desorbs to reduce the absorbed NOx in a rich environment where a rich mixture is supplied. In the system, the rich fuel mixture is supplied for a period immediately before cutoff. With the arrangement, the NOx reduction catalyst desorbs the absorbed NOx and is regenerated to absorb NOx sufficiently. At the same time, the NOx reduction catalyst is regenerated from sulfur poisoning, thereby preventing the NOx purification efficiency from being degraded.

Exhaust gas purification system for internal combustion engine

A torque shock alleviating device in a hybrid vehicle utilizing both an engine and an electric motor as drive sources, whereby a torque shock is not generated when the rich-spiking of the air-fuel mixture is carried out in order to restore the adsorbing ability of an NOx adsorbing device in the hybrid vehicle. When an engine is operated in a lean burn manner, NOx in an exhaust gas is adsorbed to an NOx adsorbing device provided in an exhaust passage. When the adsorbing ability of the NOx adsorbing device reaches a saturated level, a rich-spiking for temporarily enrichening the air-fuel mixture of the engine is carried out to restore the adsorbing ability of the NOx adsorbing device. When the output torque from the engine is increased by the rich-spiking, a regenerative braking force is generated in a motor, thereby moderating the increase in output torque from the engine by such regenerative braking force to alleviate the torque shock. An electric power generated by the regenerative braking is supplied for the charging of a battery.

Torque shock alleviating device in hybrid vehicle

An air-fuel ratio control system controls the air-fuel ratio of a mixture supplied to an internal combustion engine. An exhaust gas purifying-device arranged in the exhaust system of the engine accommodates a nitrogen oxide absorbent for absorbing nitrogen oxides in exhaust gases emitted from the engine. Nitrogen oxides absorbed by the nitrogen oxide absorbent is reduced by enriching the air-fuel ratio of the mixture supplied to the engine. The degree of the enriching of the air-fuel ratio is set to a larger value as a flow rate or flow velocity of the exhaust gases increases.

Air-fuel ratio control system for internal combustion engines

A combustion heater system for use in a moter vehicle has a combustion chamber housing a combustion pad which is heated by a pre-glow plug for vaporizing a fuel that is supplied from a fuel tank through a solenoid-operated valve to the combustion pad. The combustion chamber is supplied with air from a fan, and houses a spark plug for producing sparks in the combustion chamber to ignite a fuel vapor emitted from the combustion pad. The combustion heater system has a control unit which energizes the pre-glow plug to heat the combustion pad, actuates the solenoid-operated valve to supply the fuel to the combustion pad, and actuates the fan to supply air to the combustion chamber. The control unit subsequently energizes the spark plug to produce sparks upon elapse of a preset period of time hereby to ignite the fuel vapor emitted from the combustion pad for producing flames in the combustion chamber. To extinguish the flames, the control unit inactivates the solenoid-operated valve to stop supplying the fuel to the combustion pad and subsequently inactivates the fan to stop supplying air to the combustion chamber.

Combustion heater system for motor vehicles

An evaporated fuel control system in internal combustion engines includes a canister filled with an adsorbent for adsorbing an evaporated fuel in a fuel tank, a purge amount control device provided in the middle of a purge passage connecting an intake passage and the canister, and a fuel supply device. The purge flow rate from the start of purging is integrated, and the purge amount is reduced to a larger extent in response to a purge amount integration value becoming smaller. This improves the nature of an exhaust gas immediately after the start of purging and the like.

Growing community of inventors

Wako, Japan

Toshikatsu Takanohashi