Mazda Motor Corporation

Hiroyuki Takebayashi

Koichi Hatamura

Kenji Okamoto

Eiji Nishimura

Mitsutoshi Abe

Toshiyuki Kikuchi

Takahisa Ishihara

Kouichi Terada

Hirohide Abe

A cold-state emission-reducing strategy wherein a diagnostic apparatus examines for possible malfunctions of a control unit during cold start. The diagnosis judges that the strategy is faulty if the cumulative amount of fuel injection is equal to or smaller than a predeterminable threshold value for a faulty judgement. Thus, the abnormality of the cold-state emission-reducing strategy is accurately and easily detected, by merely calculating the cumulative amount of an injection pulse width for the injector or the cumulative amount of fuel flow during a predeterminable cumulating time period after engine start, and comparing the calculated cumulative amount with the predeterminable judgement threshold.

Diagnostic apparatus for an engine

The present invention has an object to effectively prevent deterioration of combustion characteristics when engine temperature is low. There is provided an intake pressure controller that effects control such that, when an operating condition discriminator that identifies engine temperature identifies low engine temperature after engine start-up, control by an engine controller (feedback controller ) that performs engine control on fluctuation of intake negative pressure to decrease the intake negative pressure is suppressed until the temperature of the intake passage rises to at or above a predetermined value, and such that the intake negative pressure is made larger.

Engine control system

An air-fuel ratio control system, has an air-fuel ratio feedback control for feedback controlling an-air-fuel ratio of a mixture to be supplied into an engine based on a parameter detected from an exhaust gas discharged from the engine so as to set said air-fuel ratio to a target air-fuel ratio in an internal combustion engine. Vaporized fuel is supplied from a fuel tank to the engine. During an initial interval, the supply of vaporized fuel gradually increases. Learning an updating of a control value are accomplished in the feedback control based on a deviation of the air-fuel ratio from the target air-fuel ratio during supply of the vaporized fuel. Upon a resumption of supply of vaporized fuel, a learned value setting arrangement gradually changes the learned control value from zero (0) to a learned control value obtained during a preceding period of supply of vaporized fuel according to a gradually increasing amount of supply of vaporized fuel over a given interval.

Air-fuel ratio control system for engine

A control system for an automatic transmission includes a torque converter having input and output members through which driving power is transmitted. A lock-up clutch is provided in the torque converter for connecting the input and output members without intervention of hydraulic fluid. A multiple stage transmission gear mechanism is connected with the output member of the torque converter and has a plurality of shift gear stages. A shift control device shifts the shift gear stage in accordance with a vehicle operating condition. An engaging force control device controls an engaging force of the lock-up clutch in a manner such that a slip rate of the lock-up clutch is changed. Finally, an acceleration judging device judges a required acceleration, and the engaging force control device reduces the engaging force as the required acceleration is increasd. The control is made in a manner such that the driving power transmitted through the automatic transmission is continuously changed in accordance with the required acceleration. Both acceleration performance and fuel consumption performance can be improved.

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Aki-gun, Japan

Hiroyuki Takebayashi