Mitsubishi Jidosha Kogyo Kabushiki Kaisha

Satoshi Nagashima

Kenji Saito

Hidetsugu Kanao

Yoichiro Ando

Katsunori Ueda

Hidetugu Kanao

There is provided an exhaust emission control apparatus for an internal combustion engine, which comprises a cylinder suspend operation control section that provides control to suspend combustion of suspended cylinders selected from among a plurality of cylinders according to an operating state of the internal combustion engine, a first exhaust passage connected to the suspended cylinders, a second exhaust passage connected to operating cylinders other than the suspended cylinders, a second exhaust purifying catalyst disposed in the second exhaust passage, and a first exhaust purifying catalyst disposed in the first exhaust passage and having a higher capability to purify exhaust gas than the second exhaust purifying catalyst. It is therefore possible to prevent deterioration of exhaust gas even in the case where cylinders are partially suspended.

Exhaust emission control apparatus for internal combustion engine

A failure diagnostic apparatus for an air-fuel ratio detecting device has an exhaust emission purifying device provided in an exhaust passage; an air-fuel ratio detecting unit for detecting the air-fuel ratio of an exhaust gas from the purifying device; a first determination unit for determining that the air-fuel ratio is estimated to be rich for longer than a first predetermined period of time; a second determination unit for determining that the air-fuel ratio is estimated to be lean for longer than a second predetermined period of time; and a failure diagnosis device for determining that the air-fuel ratio detecting device has failed if a variation in the air-fuel ratio, calculated based on the detected air-fuel ratios until both the first and second determination units make the determinations, is equal to or less than a predetermined value.

Failure diagnostic apparatus and method for air-fuel ratio detecting device

There is provided a failure diagnostic system for an atmospheric pressure detecting device, which is capable of rationally determining whether that device has failed or not and is capable of improving the diagnostic accuracy. The failure diagnostic system is comprised of an atmospheric pressure sensor for detecting an atmospheric pressure of the air taken into an engine; a condition determination section for determining that conditions required for determining that the atmospheric pressure sensor has failed are satisfied if the number of operations, in each of which the engine continuously operates for a predetermined period of time, has exceeded a predetermined number; and a failure diagnosis section for determining that the atmospheric pressure sensor has failed if a variation in the atmospheric pressure over a period of time equivalent to that predetermined number is equal to or less than a predetermined value and the required conditions have been satisfied.

Failure diagnostic system for atmospheric pressure detecting device

A failure diagnostic system reduces the internal pressure of a fuel tank to a predetermined negative pressure, seals off the fuel tank from the air, and then determines whether an evaporated fuel processing system has failed or not by monitoring an increase in pressure in the fuel tank. In determination, the failure diagnostic system compares a detected pressure in the fuel tank with a reference value that is increased by a predetermined rate. The failure diagnostic system stops update of the detected pressure if the detected pressure becomes higher than the reference value, and resumes update of the detected pressure if the detected pressure becomes lower than the reference value. It is therefore possible to accurately determine whether the evaporated fuel processing system has failed or not even if the pressure in the fuel tank is rapidly increased.

Failure diagnostic system of evaporated fuel processing system

There is provided a failure diagnostic system of an evaporated fuel processing system, which comprises a first failure diagnostic device that shuts off an evaporated fuel purge passage connecting a fuel tank and an engine intake passage from the air and determines whether there is any leakage from a large hole by monitoring the degree of increase in pressure in the fuel tank in which engine intake negative pressure is introduced; and a second failure diagnostic device that reduces a pressure the fuel tank to a predetermined negative pressure and seals off the fuel tank from the air to carry out failure diagnosis as to whether there is any leakage from a small hole by monitoring the degree of increase in pressure in the fuel tank. An operating range of the second failure diagnostic device is set to substantially include an operating range of the first failure diagnostic device and to be extended from the operating range of the first failure diagnostic device to include a lower intake negative pressure range.

Growing community of inventors

Okazaki, Japan

Satoshi Nagashima