Nissan Motor Company Limited

Kenji Oota

Hiroshi Iwano

Kensuke Osamura

Hiroyuki Itoyama

Takeshi Ishino

An intake-air control system for an engine enabling an intake-air quantity and a compression ratio to be variably controlled, includes sensors detecting engine operating conditions and the compression ratio, and a control unit electronically connected to the sensors for feedback-controlling the intake-air quantity based on the compression ratio as well as the engine operating conditions, while feedback-controlling the compression ratio based on the engine operating conditions. The control unit executes phase-matching between an intake-air quantity change occurring based on intake-air quantity control and a compression ratio change occurring based on compression ratio control, considering a relatively slower response in the compression ratio change than a response in the intake-air quantity change.

Intake-air control system for engine

In air-fuel ratio control apparatus and method for an internal combustion engine having an EGR valve interposed in an EGR passage between an intake manifold and an exhaust manifold, a target EGR quantity is calculated, a determination is made which of air-fuel ratio feedback controls through an EGR control and through an intake-air quantity is to be executed according to the target EGR quantity, and one of the air-fuel ratio feedback controls is selectively made according to a result of a determination of which of the air-fuel feedback controls is to be executed. During an execution of a rich spike control, the feedback control through the intake-air quantity control is unconditionally executed.

Air-fuel ratio control apparatus and method for internal combustion engine

A basic target excess air factor tLAMBDA0 and a target fresh air intake amount tQac are set base upon the operation condition of an engine ( ). A target excess air factor tLAMBDA is calculated by multiplying the ratio of a real fresh air intake amount rQac as detected by a sensor ( ) and the target fresh air intake amount tQac by the basic target excess air factor tLAMBDA0. A fuel injector ( ) is controlled so that the amount of fuel injected thereby converges to a target fuel injection amount tQf which corresponds to the target excess air factor tLAMBDA. It is possible to prevent variation of the output torque of the engine ( ) accompanying a rich spike by this control, even if the basic target excess air factor tLAMBDA0 varies abruptly, since the fuel injection amount varies in correspondence to the variation of the real fresh air intake amount rQac.

Excess air factor control device for internal combustion engine

A method for controlling an engine comprises establishing a torque correction coefficient (KA) to compensate for reducing effect of available engine torque in operating range of different excess air ratios (&lgr;) that are lower than a predetermined value (unity&equals;1). An initial base desired in-cylinder air mass (tQacb) is determined based on a requested engine torque (tTe). A desired excess air ratio (t&lgr;) is determined. The initial base desired in-cylinder air mass (tQacb) is adjusted with at least the desired excess air ratio (t&lgr;) and the correction coefficient (KA) to generate a desired in-cylinder air mass (tQac). A desired injected fuel mass (tQf) is controlled based on the desired in-cylinder air mass (tQac) to deliver the requested engine torque (tTe) with the desired excess air ratio (t&lgr;) held accomplished.

Method and system for controlling an engine with enhanced torque control

An air-fuel ratio control system for an internal combustion engine is comprised of an engine condition detecting unit and a control unit. The control unit is arranged to calculate a target engine torque on the basis of an engine operating condition, to calculate a target EGR ratio, a target excess air ratio and a target intake air quantity on the basis of the engine operating condition and the target engine torque, to calculate a target equivalence ratio on the basis of the target EGR ratio and the target excess air ratio, to calculate a target injection quantity on the basis of the engine operating condition and the target equivalence ratio, and to control an air-fuel ratio by bringing a real intake air quantity to the target intake air quantity and by bringing a real fuel injection quantity to the target fuel injection quantity.

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Kanagawa, Japan

Kenji Oota