Toyota Jidosha Kabushiki Kaisha

Yuichi Kohara

Shuichi Hanai

Noriyuki Iden

Akihiro Katayama

Tokiji Ito

Kazuyuki Noda

Masashi Hakariya

Yoshihisa Oda

Isao Nakajima

Shin Adachi

Kiyotaka Kushihama

Hitoshi Tanaka

Shota Kitano

Katsumi Adachi

Takahiro Uchida

Tokiji Itoh

An apparatus for detecting imbalance abnormality in an air-fuel ratio between cylinders in a multi-cylinder internal combustion engine according to the present invention increases a fuel injection quantity to a predetermined target cylinder to detect imbalance abnormality in an air-fuel ratio between cylinders at least based upon a rotation variation of the target cylinder after increasing the fuel injection quantity. The increase in the fuel injection quantity is carried out in the middle of performing the post-fuel-cut rich control. Since timing of the post-fuel cut rich control is used to increase the fuel injection quantity, the exhaust emission deterioration due to abnormality detection execution can be prevented as much as possible.

Apparatus for detecting imbalance abnormality in air-fuel ratio between cylinders in multi-cylinder internal combustion engine

An abnormality detection apparatus for a multi-cylinder internal combustion engine changes a fuel injection quantity of a predetermined target cylinder to detect an abnormality of an internal combustion engine based on values of rotational variations relating to the target cylinder detected before and after the change of the fuel injection quantity. The abnormality detection apparatus corrects the values of the rotational variations relating to the target cylinder detected before and after the change of the fuel injection quantity based on at least one of the number of revolutions of the engine and an engine load at a corresponding detection time.

Abnormality detection apparatus and abnormality detection method for multi-cylinder internal combustion engine

To provide an apparatus for evaluating the deterioration condition of a catalyst of an internal combustion engine that can improve the accuracy of an evaluation of the deterioration condition of a catalyst and can suppress a worsening of emissions. The apparatus forcedly sets the air/fuel ratio upstream of a catalyst provided in an exhaust system of an internal combustion engine at a rich condition or a lean condition on the basis of a detected value of a sub Osensor downstream of the catalyst in the internal combustion engine and evaluates the deterioration condition of the catalyst. The air/fuel ratio control is reversed so that the air/fuel ratio upstream of the catalyst becomes a lean condition or a rich condition when 'egasum' has reached a predetermined value Ga, 'egasum' being an integrated value of an admitted air volume (an integration count of the amount of exhaust gas passing through the catalyst) in the period after the sub Osensor outputs a detected value, which shows a rich condition or a lean condition, until the reversing of the output of the sub Osensor.

Apparatus for evaluating deterioration condition of catalyst of internal combustion engine

A failure test apparatus for a fuel-vapor purging system for adsorbing fuel vapor in a fuel tank into a canister and for purging fuel to an intake system of an internal combustion engine as needed. The purging system has at least one valve. A first test unit provides a differential pressure between the inside and the outside of the fuel-vapor purging system, measures the internal pressure with the fuel-vapor purging system in an airtight condition, and determines whether a leak exists in the fuel-vapor purging system from the behavior of the internal pressure. The test by the first test unit involves a differential-pressure forming process of creating a differential pressure between the inside and the outside of the fuel-vapor purging system, a sealing process of making the fuel-vapor purging system airtight when the differential pressure exists, and a differential-pressure releasing process for releasing the differential pressure. In association with one or more of the processes, a second test unit measures the internal pressure of the fuel-vapor purging system to detect a failure in any valve actuated in one of the processes based on the behavior of the internal pressure.

Failure test apparatus for fuel-vapor purging system

An improved diagnosis apparatus for detecting leakage of a fuel vapor purge system that purges fuel vapor from a fuel tank to an intake passage of an engine. The apparatus includes a pressure sensor and a purge valve. The pressure sensor detects the pressure in the purge system. The purge valve connects the purge system with the intake passage for lowering the purge system pressure to a predetermined pressure level. After the purge system pressure is lowered to the predetermined level, the purge system is sealed. The apparatus measures the rate of pressure change immediately after the purge system is sealed. The apparatus subsequently measures the rate of pressure change when the purge system pressure reaches a second reference pressure value and computes the ratio of the rates. The apparatus diagnoses whether there is a leak in the purge system based on the ratio and the rate of pressure change at the second reference pressure value.

Diagnosis apparatus for fuel vapor purge system

A test apparatus for a fuel vapor purge system that performs frequent tests. The testing apparatus detects leakage of fuel vapor from a system passage by sealing the system passage and monitoring changes in the pressure. After the test, the apparatus applies atmospheric pressure to the system passage. Therefore, the pressure in the system passage is quickly restored to atmospheric pressure.

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Toyota, Japan

Yuichi Kohara