Mazda Motor Corporation

Tomomi Watanabe

Junichi Taga

Yusuke Oda

Hirofumi Nishimura

Junsou Sasaki

Akihide Takami

Kiyotaka Mamiya

Tadataka Nakazumi

Michihiro Imada

Shigeyuki Hirashita

Naoki Mine

Mitsuo Hitomi

Hiroshi Yamada

Masahisa Yamakawa

Keiji Araki

Hiroyuki Yamashita

Hideharu Iwakuni

Toshiaki Nishimoto

Kenji Okamoto

Takafumi Nishio

Youichi Kuji

Tatsuya Fujikawa

Katsuhiko Yokooku

Tadashi Kaneko

Makoto Kyogoku

Yuya Honda

Fumihiko Saito

Tomoaki Saito

Yoshitaka Wada

Masayuki Kuroki

Itaru Okuno

Yoshiyuki Shinya

Katsumi Okazaki

Takuya Yamada

Nobuo Takeuchi

Tatsuya Tanaka

Yoshitaka Tabara

Kazunori Hirabayashi

Mikinori Ohashi

Akira Takai

Kyohei Yasuda

Yoshiteru Nakayama

Atsushi Suzuki

Korin Hata

Nobuyuki Furuichi

Terunori Kondou

Yuichiro Tanaka

Sho Shimamoto

Kazuya Rokuta

Naoki Kishikawa

Katsumi Okazaka

An engine is provided, which includes a combustion chamber defined by a crown surface of a piston, an inner wall surface of a cylinder in which the piston is slidably accommodated, and a pentroof-type ceiling surface formed in a cylinder head and formed with an intake port and an exhaust port. The crown surface includes an exhaust-side bottom part, an intake-side bottom part, an exhaust-side sloped surface rising toward a center part of the crown surface from the exhaust-side bottom part, an intake-side sloped surface rising toward the center part from the intake-side bottom part, and a flat surface provided continuously between upper ends of the exhaust-side and intake-side sloped surfaces, and extending perpendicularly to a cylinder axial direction in the center part of the crown surface. A surface area of the flat surface is larger than a surface area of the exhaust-side sloped surface.

Engine with combustion chamber

An engine system is provided, which includes an engine, a swirl control valve, and a controller. The engine includes a cylinder, a piston, and a fuel injection valve provided incliningly with respect to an axial direction of the piston and configured to directly inject fuel into the cylinder. The swirl control valve is provided inside an intake passage and generates a swirl flow inside the cylinder at least when the valve closes. When an engine load is below a given threshold, the controller controls the swirl control valve to close, and controls the fuel injection valve to inject fuel during an intake stroke. While the engine load is below the threshold, at a fixed engine speed, the controller controls to advance a fuel injection timing when the engine load is at a first load, compared with at a second load higher than the first load.

Engine system

An engine system is provided, which includes an engine, a swirl control valve, an EGR passage, an EGR gas adjusting mechanism, and a controller. The engine includes a cylinder, a piston, and a fuel injection valve. The swirl control valve is provided inside an intake passage and generates a swirl flow inside the cylinder when it closes. When an engine load is at or below a given threshold, the controller controls the swirl control valve to close. While the engine load is the threshold or below, the controller controls the EGR gas adjusting mechanism such that, at a fixed engine speed, an increase rate of an EGR gas amount with respect to an increase in the engine load is lower in a first load range than in a second load range, the first load range being on a higher load side of the second load range and including the threshold.

An intake system of an engine supplies gas at least containing fresh air to each cylinder. The system includes an EGR passage that communicates with an internal space of a downstream intake passage and introduces some EGR gas into the downstream intake passage. The EGR passage includes a projected section in a substantially polygonal or cylindrical shape that is projected to the internal space of the downstream intake passage. The projected section is formed in such a shape that a projection length Hin an outer circumferential surface on an upstream side is longer than a projection length Hin an outer circumferential surface on a downstream side.

Engine intake system

A control system of an engine is provided, which controls, by using a tumble flow, a behavior of fuel that is directly injected into a combustion chamber formed inside a cylinder of the engine. The control system includes a fuel injector for directly injecting the fuel into the combustion chamber, a tumble flow generator for generating the tumble flow within the combustion chamber, an ignition timing control module for controlling an ignition plug to ignite after a top dead center on compression stroke of the cylinder in a cold state of the engine, and a fuel injector control module for controlling the fuel injector to inject the fuel at an intake-stroke injection timing, a compression-stroke-early-half injection timing, and a compression-stroke-latter-half injection timing. The fuel injector control module controls the fuel injector to inject the fuel toward a vortex center of the tumble flow at the compression-stroke-early-half injection timing.

Control system of engine

In a flexible-fuel engine capable of using fuel containing alcohol as fuel to be combusted in a cylinder, the geometric compression ratio is set to 12 or more, the engine is started by using fuel containing alcohol, an intake valve closing timing at an engine start time is set to an advance angle side than a first reference timing being a timing corresponding to a most retarded angle position out of intake valve closing timings capable of starting the engine in combusting fuel of alcohol 100% in the cylinder at a first intake temperature, and is set to a timing on a retarded angle side than a second reference timing being a timing corresponding to a most advanced angle position out of intake valve closing timings capable of avoiding pre-ignition in combusting fuel of gasoline 100% at an engine start time at a second intake temperature.

Flexible-fuel engine

A controller (an engine controller) feeds a fuel into a cylinderthrough a fuel feeder (including a fuel injection valveand a fuel feeding system) when the cylinderis in an intake stroke and a compression stroke and if an engine body (an engine) is both in a cold running phase and under a heavy load. The engine body at or below a predetermined temperature is in the cold running phase. The load applied to the engine body is heavy when the engine body is under at least a predetermined load. The controller also lowers the upper limit of the charging efficiency of the engine body as the vaporization rate of the fuel fed into the cylinder decreases.

Control device for spark-ignition engine

When a catalytic converter in an exhaust passage is in an un-activated state, an intake air amount is increased, as compared to when the converter is in an activated state under the same engine operation condition, and an ignition timing is retarded beyond a TDC of a compression stroke. The ignition timing is set such that a retard amount thereof from the TDC becomes larger as an external load causing a rotational resistance of an engine becomes lower. A valve opening start timing of an exhaust valve is set such that, when the external load is lower than a given reference load, the valve starts opening, before an in-cylinder pressure reaches a peak, according to combustion of an air-fuel mixture ignited at the above ignition timing, in a subsequent expansion stroke, wherein the in-cylinder pressure is based on an assumption that the valve is maintained in a valve-closed state.

Catalyst advanced warmup control device for spark ignition engine

Disclosed is a direct-injection spark-ignition engine designed to promote catalyst activation during cold engine operation. A fuel injection timing for a fuel injection period in an compression stroke (second fuel injection period F2) is set to allow a first fuel spray Ga injected from a first spray holeto enter a cavityin a piston crown surface, and allow a second fuel spray Gb to impinge against a region of the piston crown surfacelocated closer to an injector than the cavity, so as to cause the second fuel spray Gb having a lowered penetration force due to the impingement to be pulled toward the cavityby a negative pressure generated in the cavityas a result of passing of the first fuel spray Ga therethrough. The direct-injection spark-ignition engine can maximally hold an injected fuel spray around a spark plug to reliably stabilize a combustion state in a combustion mode for promoting catalyst activation during cold engine operation, while enhancing combustion efficiency in a homogenous combustion mode during normal engine operation.

Direct-injection spark-ignition engine

A method of operating an internal combustion engine having a combustion chamber with a piston and a spark plug, comprising during a first mode, bringing the temperature of the combustion chamber to auto-ignition temperature by adjusting engine operating conditions and producing auto-ignition in said combustion chamber without requiring spark from said spark plug; and during a second mode, bringing the temperature of the combustion chamber close to auto-ignition temperature by adjusting engine operating conditions, forming a small cloud of stratified air-fuel mixture near said spark plug, igniting said fuel cloud by a spark form said spark plug, and then causing cylinder pressure to rise, thereby producing auto-ignition at other sites in said combustion chamber wherein said first mode is implemented in a first operating range and said second mode is implemented only in a second operating range where engine speed and load are lower than said first operating range.

Method of operating an internal combustion engine

An engine control system causes a NOx trapping substance to release absorbed NOx by increasing an amount of fuel and spraying the fuel through primary fuel injection which is made at a primary fuel injection timing near a dead top center of a compression stroke and post-fuel injection which is made at a post-fuel injection timing between an expansion stroke and an exhaust stoke after said primary fuel injection with a retardation which is large at the beginning of implementation of the post-fuel injection and, thereafter changed small.

System for controlling engine

An exhaust gas purifying system includes an exhaust gas purifying catalyst having a nitrogen oxide absorbing material which is installed in an exhaust line of an engine and performs split fuel injection to inject fuel directly into each combustion chamber partly during a suction stroke and partly during a compression stroke to provide and supply an increased amount of carbon monoxide to the nitrogen oxide absorbing material so as thereby to desorb sulfur oxides from the nitrogen oxide absorbing material.

Exhaust gas purifying system for engine

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 air-fuel control system for an internal combustion engine is equipped with an exhaust system having a catalytic converter, a linear O.sub.2 sensor and a .lambda.O.sub.2 sensor for feedback controlling an air-fuel ratio on the basis of output representative of oxygen content from at least the linear O.sub.2 sensor. The system delivers a target air-fuel ratio of a fuel mixture. A determinant output, based on which the air-fuel ratio is feedback controlled, is shifted from output from the linear O.sub.2 sensor to output from the .lambda.O.sub.2 sensor before the linear O.sub.2 sensor is effectively active.

Air-fuel ratio control system for engines

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.

Engine control system

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Hiroshima, Japan

Tomomi Watanabe