Toyota Jidosha Kabushiki Kaisha

Nippondenso Co., Ltd.

Hidetoshi Amano

Toshiaki Mizuno

Shinichi Abe

Mitsuharu Taura

Shin Adachi

A misfire detecting apparatus for an internal combustion engine has a start determinator, a rotation counter, a misfire detector, a misfire calculator, a setting means, an abnormality determinator, and a warning means. The start determinator determines a starting condition of the internal combustion engine. The rotation counter counts a total number of rotations of the internal combustion engine. The misfire detector detects a misfire of the internal combustion engine. The misfire calculator calculates a rate of misfire using data from the misfire detector, and the rate of misfire is the number of misfires per a predetermined total number of rotations. The setting means sets a basic rate of misfire in response to the start condition of the internal combustion engine. The abnormality determinator determines an abnormal condition of the internal combustion engine when the rate of misfire calculated by the misfire calculator is greater than the basic rate of misfire set by the setting means. The warning means warns of an abnormality of the internal combustion engine when the abnormality determinator determines an abnormal condition of the internal combustion engine. The detection whether the internal combustion engine is abnormal or not can be accurate by this misfire detecting apparatus.

Misfire detecting apparatus for an internal combustion engine and a method for detecting misfires

In a diagnostic apparatus for an internal combustion engine, an electronic control unit recognizes occurrence of a misfire in the engine based on fluctuations of the rotational speed of a crankshaft detected by a rotation speed sensor. Based on the detected incidences of misfire, the electronic control unit performs diagnostics. The electronic control unit turns on a warning light when, after the first diagnosis of the presence of an abnormality, a second diagnosis of the presence of an abnormality is made without the return of the engine to the normal state being recognized after a restart of the engine.

Internal combustion engine diagnostic apparatus

A rotational fluctuation amount between consecutively ignited cylinders is sequentially calculated. When the rotational fluctuation amount exceeds a first predetermined value and an emergence interval of the rotational fluctuation assumes a predetermined value, or when the rotational fluctuation amount exceeds a second predetermined value larger than the first predetermined value, the rotational fluctuation is judged to result from misfire. A cylinder subjected to the rotational fluctuation is then specified. By comparing rotational fluctuation amounts in the specified cylinder, and the two cylinders firing immediately after the specified cylinder, a determination is made as to whether it is only the specified cylinder which has misfired, the specified cylinder and the cylinder immediately following the specified cylinder have consecutively misfired, or the specified cylinder and a cylinder other than the immediately following cylinder have intermittently misfired.

Misfire detecting device of multicylinder internal combustion engine

A device for accurately detecting misfiring repetitively occurring in the opposing cylinders every 360.degree. CA. An angular velocity detecting means detects the angular velocity of rotation of the crankshaft for each cylinder at the time of combustion. A first rotational change calculation means calculates a first amount of change in the rotation by finding a deviation of angular velocity between the two cylinders of consecutive combustion strokes. A second rotational change calculation means calculates a second amount of change in the rotation by finding a deviation of angular velocity between the two cylinders 360.degree. CA before the moment at which the first rotational change calculation means has detected the angular velocity to calculate the first amount of change in the rotation. An adder means adds up the first amount of change in the rotation calculated by the first rotational change calculation means and the second amount of change in the rotation calculated by the second rotational change calculation means. A misfiring detecting means detects misfiring that occurs every 360.degree. CA by comparing the amount of change in the rotation added up by said adder means with a predetermined discrimination value.

Device for detecting misfiring in a multi-cylinder internal combustion

The basic fuel injection time duration or the basic injector opening time is computed on the basis of an intake pressure and an engine speed. A start temperature correction value is selected on the basis of the engine temperature at the time of or immediately after the start up of the engine and attenuated in accordance with the time elapsed after the start up of the engine, such that, the lower the engine temperature is at the time of start up, the greater the start temperature correction value is. The rate of fuel injection rate is controlled by correcting the basic fuel injection time on the basis of the start temperature correction value and a condition of the engine.

Method and apparatus for controlling fuel injection rate in internal

The amount of engine acceleration is detected as the amount of change in the absolute pressure in the intake passage, and an asynchronous fuel injection is conducted regardless of the crank position as the amount of acceleration exceeds a predetermined reference value. In ordinary state of engine operation, the synchronous fuel injection is conducted in synchronism with the crank rotation such that the air-fuel ratio of the mixture coincides with the stoichiometric one, upon sensing the air-fuel ratio from the content of oxygen remaining in the exhaust gas. The mixture is made richer or leaner than the stoichiometric one in accordance with the state of operation of the engine. The judging level for the judgement as to whether the asynchronous fuel injection is necessary or not is increased or decreased in accordance with the air-fuel ratio so that the asynchronous fuel injection is conducted taking into account also the air-fuel ratio.

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Okazaki, Japan

Hidetoshi Amano