Mazda Motor Corporation

Mazada Motor Corporation

Michihiro Imada

Kiyotaka Mamiya

Masayuki Tetsuno

Hirofumi Nishimura

Junichi Taga

Takeo Yamauchi

Masayuki Kuroki

Tomomi Watanabe

Masahiko Shigetsu

Kouhei Iwai

Yasuyoshi Hori

Hideshi Terao

Takanobu Morimasa

An exhaust-gas cleaning device for an engine comprises an HC-adsorbing catalytic converter disposed in an exhaust passage, the HC-adsorbing catalytic converter including an HC-adsorbing material which adsorbs HC contained in exhaust gas at low temperatures and releases adsorbed HC as the temperature increases, an oxygen storage material which occludes oxygen when the concentration of oxygen in the exhaust gas is high and releases occluded oxygen as the oxygen concentration drops, and a three-way catalys metal layer which oxidizes HC released from the HC-adsorbing material, and an oxygen concentration controller which controls the oxygen concentration in the exhaust gas on the upstream side of the HC-adsorbing catalytic converter in such a manner that oxygen is released from the oxygen storage material when the engine is in an operating condition in which HC is released from the HC-adsorbing material.

Exhaust-gas cleaning device for engine

Upon refreshing a catalyst (,) in steps SA,to SA,the air-fuel ratio of each combustion chamber (,) of an engine (,) is dither-controlled to periodically vary to the rich and lean sides of a target value (A/F&equals;15 to 16) in steps SA,and SA,In step SA,an injector (,) divisionally injects fuel in two injections within the period from the intake stroke to the compression stroke of each cylinder, thus accomplishing weakly stratified combustion. In step SA,the opening of an EGR valve (,) is controlled to recirculate a large amount of exhaust gas to an intake path (,) so as to achieve around 40% EGR ratio.

Control apparatus for spark ignition type direct injection engine

A control device for controlling a direct injection engine provided with an injector for injecting fuel directly into a combustion chamber in a cylinder thereof and a throttle valve is switchable between a stratified charge combustion mode and a uniform charge combustion mode. The control device predicts switching to the uniform charge combustion mode based on a change in the target load Piobj during engine acceleration in the stratified charge combustion mode, and corrects the target load Piobj so that the opening of the throttle valve approaches the opening suited for the uniform charge combustion mode prior to the switching to the uniform charge combustion mode when such combustion mode switching has been predicted. This control device prevents torque shock due to the combustion mode switching during engine acceleration without causing a deterioration in fuel economy or in vehicle acceleration performance.

Control device for direct injection engine and an injection engine provided with a controller

A fuel injection control system for a direct injection-spark ignition engine determines an injection pulse width corresponding to a given quantity of fuel with which an injector is kept open, controls the injector to spray a given quantity of fuel in a compression stroke while the engine operates in a zone of lower engine loads specified for lean stratified charge combustion so that the fuel is stratified around an ignition plug to cause lean stratified charge combustion so as thereby to provide an air-fuel ratio greater than a stoichiometric air-fuel ratio, executes fuel injection feedback control to control a quantity of fuel injection based on an air-fuel ratio detected by an oxygen sensor, causes the injector to spray a given quantity of fuel through a plurality of intake stroke split injection in a specified engine operating zone in which the fuel injection feedback control is performed to maintain at least a stoichiometric air-fuel ratio while the engine operates with lower loads, learns a fuel injection quantity characteristic of the injector with respect to injection pulse width for each intake stroke split injection based on a value controlled by the fuel injection feedback control during execution of the intake stroke split injection to determine a leaning correction value, and makes the learning correction value reflect on the control of the quantity of fuel in a minute injection zone specified within the specified engine operating zone for the lean stratified charge combustion.

Fuel injection control system for direct injection-spark ignition engine

An engine control system for an engine equipped with a swirl control valve which is operative in operation modes different in fuel injection form according to engine operating conditions judges based on a change in an engine operating condition whether a mode shift to one operation mode to another is demanded and controls the swirl control valve so as to attain a target opening for the one engine operation mode while keeping a specific mode shift waiting until the swirl valve opening reaches a limit value permissible in one engine operation mode into which the specific mode shift is made when the swirl control valve is judged to be out of the limit value.

Control system for an engine

An engine control system for a direct injection-spark ignition type of engine determines a target load based on an engine speed and an accelerator pedal travel, determines target air-to-fuel ratio based on an amount of intake air and the target engine load, and determines an amount of fuel injection based on the target air-to-fuel ratio, so as thereby to control engine output torque balancing the target engine load even during a transitional operating state.

An air intake control system for an engine equipped with an exhaust gas recirculation feature controls an exhaust gas recirculation valve according to an amount of air charge dictated by an amount of intake air detected by an air flow sensor to deliver a target amount of air charge and control an amount of air charge meeting an estimated amount of air charge estimated under the condition that the control of exhaust gas recirculation valve according to an amount of air charge is interrupted.

Air intake control system for engine equipped with exhaust gas

A fuel control unit and a fuel injection control method for a multi-cylinder engine adjust the pulse width of asynchronous injection so as to set the air-fuel ratio of a fuel-air mixture in a first cylinder to 17 or more but under 21 if it is determined according to an engine speed (Ne) that an engine is in an idling mode and if it is determined according to the opening of a throttle valve that a condition for starting the acceleration of the engine has been satisfied. The foregoing first cylinder is the cylinder in which compression pressure increases first following the determination described above.

Fuel control unit and fuel injection control method for multi-cylinder

An engine control system for controlling operation of an engine of a type injecting fuel directly into a combustion chamber in different injection modes according to engine operating conditions has a map of engine control values with respect to specified engine operating conditions at intersection points of a grid pattern in which engine control values at extreme intersection points adjacent to a boundary between adjacent injection modes is discontinual. The engine control system calculates an engine control value for an engine operating condition by interpolation with the aid of engine control values at the intersection points and determines an engine control value for an engine operating condition at a point closer to the boundary than the extreme intersection point of one injection mode based on engine control values at intersection points of the one injection mode only.

Control system for controlling a fuel direct injection type of engine

An engine control system for an automobile engine of, for example, the type which injects fuel directly into an combustion chamber (16) and executes a fuel-cut control under a specified engine operating condition establishes a stratified charge combustion mode and a homogeneous charge combustion mode selectively according to engine operating conditions following termination of the fuel-cut control and shuts off nearly completely an engine throttle valve (28) during execution of the fuel-cut control and opens the engine throttle valve (28) so as to variably control an amount of intake air passing through an intake passage (24) into the combustion chamber (16) before the stratified charge combustion mode is established following termination of the fuel-cut control.

Engine control system

An engine combustion condition judging method for detecting a crank angle speed of a multiple cylinder engine, for judging a combustion condition of each of cylinders of the engine based on the detection of the crank angle speed, wherein the improvement includes the steps of setting a predetermined crank angle range selectively determined within a range between a crank angle at which a combustion substantially terminate in a given cylinder and another crank angle at which a combustion substantially start in the next cylinder for detecting a crank angle speed property, and judging the combustion condition based on said crank angle speed property within the predetermined crank angle range. The combustion condition can be obtained reliably so that an appropriate A/F control can be accomplished irrespective of the engine operating condition.

Engine control method

An engine control system in which an air fuel ratio (A/F) is controlled to a lean value closer to a stable combustion limit than a theoretical air fuel ratio under a predetermined operating range, comprising base air fuel ratio control element for setting a target air fuel ratio close to the stable combustion limit and for setting a base air fuel ratio control gain so as to accomplish the target air fuel, a combustion condition judging element for judging a combustion condition of each of cylinders of the engine, air fuel ratio compensating element for compensating the air fuel control gain based on the combustion condition judging element and ignition timing control means for setting an ignition timing in accordance with the target air fuel ratio in the predetermined operating range and for compensating the ignition timing taking account of the compensation of the air fuel ratio by the air fuel ratio compensating element. An accurate and reliable A/F control along with the ignition timing control can be accomplished to improve the fuel consumption efficiency and emission performance.

During an air-fuel ratio feedback control based on an oxygen concentration in exhaust gases which converges an air-fuel ratio toward a target ratio suitable for a satisfactory purifying efficiency of a catalyst, the air-fuel ratio is coercively deflected so as to make a fuel mixture richer and leaner alternatively. An extent of deflection of the air-fuel ratio is set larger before the catalyst has not yet been activated sufficiently.

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Hiroshima, Japan

Michihiro Imada