Toyota Jidosha Kabushiki Kaisha

Kenichiro Kawase

Mamoru Yoshioka

Noritake Mitsutani

Hideki Miyahara

Kiyoshi Asada

Keisuke Yamashita

Yousuke Hashimoto

A diagnosis device for an engine, the diagnosis device includes an electronic control unit. The electronic control unit is configured to execute EGR diagnosis processing to diagnose whether or not the EGR device operates normally while a vehicle is being decelerated, execute air flow meter diagnosis processing to diagnose whether or not the air flow meter is normal while the vehicle is decelerated, execute the EGR diagnosis processing after starting the air flow meter diagnosis processing, and execute the EGR diagnosis processing when the air flow meter diagnosis processing has not been completed and predetermined conditions that a duration of deceleration of the vehicle being shorter than a diagnosis time that is required to execute the air flow meter diagnosis processing are fulfilled.

Diagnosis device for internal combustion engine, and diagnosis method for internal combustion engine

A malfunction diagnostic device for an exhaust gas control device is provided. The malfunction diagnostic device includes a malfunction determination unit that determines an exhaust gas control device provided in an exhaust system of an internal combustion engine malfunctions when a parameter that indicates exhaust gas purification performance of the exhaust gas control device crosses a threshold. A deterioration determination unit determines the degree of deterioration of the exhaust gas control device. A variable threshold setting unit variably sets the threshold based on the degree of deterioration of the exhaust gas control device in such a manner that the likelihood that the exhaust gas control device is determined to be malfunctioning is lower at lower degrees of deterioration of the exhaust gas control device.

Malfunction diagnostic device for exhaust gas control device

An abnormality diagnosis device for an exhaust gas recirculation device in an internal combustion engine is provided. The exhaust gas recirculation device has an exhaust gas recirculation valve that adjusts the amount of recirculation exhausts gas returned from an exhaust passage to an intake passage of the engine. The abnormality diagnosis device includes a control section that changes the exhaust gas recirculation valve to diagnose an abnormality in the exhaust gas recirculation device. When the abnormality diagnosis execution condition is met, the control section, prior to the execution of the valve closing operation, inhibits the opening degree adjustment and executes a valve opening process to increase the opening degree of the valve from the opening degree at the time to a second target opening degree greater than the first target opening degree.

Abnormality diagnosis device for exhaust gas recirculation device

An abnormality diagnosing apparatus for a glow plugprovided in an engine. The glow plugis energized by power supply from a batteryduring a glow period from starting of the engineto completion of engine starting. First, on the basis that power output edf from an alternator, which is driven to charge the battery, is within an appropriate range and that the variation &#x394;edf of the power output edf at the end of the glow period is not more than a reference value a, it is determined if there is a possibility of an abnormality in the glow plugAfter the determination, the plugis energized temporarily. Then, on the basis that the power output edf is within a modified appropriate range, which has a greater upper limit than the previous appropriate range and that the variation &#x394;edf while the plugis energized is not more than the reference value a, it is determined that the an abnormality actually occurred. Accordingly, failure of determination of the presence of an abnormality due to deterioration of the batteryis prevented when an abnormally has actually occurred.

Abnormality diagnosing apparatus for a glow plug

An evaporation fuel processing mechanism supplies fuel vapor in a fuel tank to a canister via a vapor passage and purges fuel in the canister to an air-intake passage of an internal combustion engine via a purge passage when the internal combustion engine is operated. This mechanism supplies fuel vapor in the fuel tank when refueling to the canister via a breather passage. The breather passage has a pressure sensitive valve that opens in response to a variation in pressure in the fuel tank during refueling. An air-fuel ratio variation limiting apparatus determines whether the pressure sensitive valve is open and limits a variation in the air-fuel ratio when the pressure sensitive valve is open.

Growing community of inventors

Okazaki, Japan

Kenichiro Kawase