Mazda Motor Corporation

Kazutoyo Watanabe

Masahisa Yamakawa

Junsou Sasaki

Kazuhiro Nagatsu

Noriyuki Ota

Kouhei Iwai

Shuji Oba

Naoya Watanabe

Hiroyuki Kurita

Keiji Araki

Takashi Youso

Yoshihisa Nou

Naohiro Yamaguchi

Tatsuya Takahata

Tatsuya Koga

Shinji Watanabe

Nobuhiko Yokoyama

Takaaki Nagano

Yukio Haizaki

Yasunori Matoba

Katsuya Murakami

Motoo Hayakawa

Junichi Seguchi

In response to a switching demand from an all-cylinder operation to a reduced-cylinder operation, the amount of air to be taken into each of cylindersA toD is made larger than the amount of air during the all-cylinder operation in a normal state. Preparatory control of changing the ignition timing of ignition device to a timing on the retard side with respect to the ignition timing during the all-cylinder operation in the normal state is executed. After termination of the preparatory control, the reduced-cylinder operation is started. During execution of the preparatory control, the valve closing timing of an exhaust valveis changed to a timing on the advance side with respect to the valve closing timing thereof during the all-cylinder operation in the normal state so as to reduce the amount of internal EGR gas in at least a part of an operating range C.

Engine control apparatus

A variable cylinder engine is provided. The engine includes an engine body having a plurality of cylinders, a cooling mechanism for cooling the engine body by using a coolant, and a controller for controlling a temperature of the coolant and changing the number of active cylinders according to an operating state of the engine. The controller reduces the number of active cylinders in a reduced-cylinder operating range set within a partial engine load range, and expands the reduced-cylinder operating range to a higher engine load side as the coolant temperature becomes lower.

Variable cylinder engine

A variable cylinder engine is provided. The engine includes an engine body having a plurality of cylinders, a cooling mechanism for cooling the engine body, and a controller for controlling the cooling mechanism and changing a number of active cylinders according to an operating state of the engine. The controller reduces the number of active cylinders in a reduced-cylinder operating range set within a partial engine load range, and in a first reduced-cylinder range set within a high load part of the reduced-cylinder operating range, the controller improves a cooling performance of the cooling mechanism compared with that in a second reduced-cylinder range set within a low load part of the reduced-cylinder operating range.

A control device of a spark-ignition gasoline engine is provided. The control device includes a controller for operating the engine body by controlling at least a fuel injection valve, an ignition plug, and a fuel pressure variable mechanism. Depending on the engine load range, the controller sets the combustion mode to a compression-ignition mode or a spark-ignition mode. In each mode, the controller also controls the fuel pressure, and the timing of fuel injection and ignition. The controller may also performs external EGR control in each mode.

Control device of spark-ignition gasoline engine

The disclosure provides a control device of a spark-ignition gasoline engine. When an operating state of an engine body is within a low engine speed range, a controller operates a fuel pressure variable mechanism so that a fuel pressure is higher within a high engine load range compared to a low engine load range, the controller operates, within the high engine load range, a fuel injection mechanism to perform at least a fuel injection into the cylinder by a cylinder internal injection valve at a timing during a retard period from a late stage of a compression stroke to an early stage of an expansion stroke, and the controller operates, within the high engine load range, an ignition plug to ignite at a timing during the retard period and after the fuel injection.

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Higashihiroshima, Japan

Kazutoyo Watanabe