Unisia Jecs Corporation

Nissan Motor Company Limited

Takamasa Ueda

Yuki Nakajima

Kenichi Machida

Hirokazu Shimizu

Hiraku Ohba

Hatsuo Nagaishi

Hajime Hosoya

Hiroshi Iwano

Junichi Furuya

Hiraku Ooba

In a direct-injection gasoline engine which is so constituted as to execute a twice-injection mode for injecting the fuel in the intake stroke and in the compression stroke, respectively, at the time of change-over between the stratified mode and the homogeneous mode, the fuel injection amount is set to be constant in either the intake stroke or the compression stroke in the twice-injection mode, and an amount obtained by subtracting the above constant amount from the required injection amount is injected in the other stroke. Setting the fuel amount to be constant at one injection timing makes it easy to comply with the operation for controlling the fuel injection in the twice-injection mode.

Apparatus for controlling fuel injection for a direct-injection gasoline

A fuel injection control system for a cylinder direct injection spark-ignition internal combustion engine judges a homogeneous charge combustion condition which requires homogeneous charge combustion and a stratified charge combustion condition which requires stratified charge combustion, in accordance with an engine operating condition. Fuel is supplied on an intake stroke so as to form a rich equivalent ratio in the homogeneous charge combustion, and fuel is supplied on a compression stroke so as to form a lean equivalent ratio in the stratified charge combustion, with the rich equivalent ratio being richer in fuel than the lean equivalent ratio. The system then gradually changes over an equivalent ratio within a range between the rich and lean equivalent ratios when engine operation is changed over between the homogeneous charge combustion condition and the stratified charge combustion condition. The system then injects first and second quantities of fuel into a cylinder of the engine respectively on intake and compression strokes in each cycle of the cylinder at least at a predetermined time during a time period in which the equivalent ratio is gradually changed over.

Fuel injection control system for internal combustion engine

The present invention aims at preventing such a situation that anyone of the divided injection amounts becomes less than a minimum compensation amount for a fuel injection valve, in case of conducting a two-step injection (weakly stratified combustion) in which a part of fuel is injected during intake stroke and the remaining fuel is injected during compression stroke. To this end, at the time of instructing to conduct the two-step injection, a whole injection amount TI is divided into: an injection amount TIH for homogeneous combustion to be injected during intake stroke, and an injection amount TIS for stratified combustion to be injected during compression stroke, based on a division ratio corresponding to a target air-fuel ratio. Further, each of the injection amounts TIH and TIS after division is compared with a minimum compensation amount MIN for the fuel injection valve. Based on the result of the comparison, the injection amount, which has a smaller division ratio, is set to be zero, and the injection amount, which has a larger division ratio, is set to be the whole injection amount TI, when either one of the injection amounts TIH and TIS is judged to be less than the minimum compensation amount MIN. Alternatively, the injection amount, which has the smaller division ratio, is set to be the minimum compensation amount MIN, and the injection amount, which has the larger division ratio, is set to be the remainder obtained by subtracting the minimum compensation amount MIN from the whole injection amount TI.

Control apparatus for direct injection spark ignition type internal

In the control method and apparatus of a direct injection gasoline engine, as for the uniform charge combustion mode performing only the intake stroke injection and the stratified charge combustion mode performing only the compression stroke injection, the injection timing is determined by referring to the injection timing map set for each mode. On the other hand, in the double injection mode performing the intake stroke injection and the compression stroke injection, the injection timing map for the intake stroke injection and the injection timing map for the compression stroke injection are both equipped, and the injection timing in the intake stroke injection is determined by the fuel quantity being injected by the intake stroke, and the injection timing in the compression stroke injection is determined by the fuel quantity being injected by the compression stroke.

Control method and control apparatus of direct injection gasoline engine

Growing community of inventors

Yokohama, Japan

Takamasa Ueda