Abstract: An operating position select device has a select lever unit, a mode shift unit to shift operation modes of the automatic transmission, a mechanically connecting means connecting them, and an assist actuator controlled be a control unit to assist a select lever. The control unit includes an improper-halt judging part for judging an improper halt of the lever based on an operating position, a basic target reaction-force setting part for setting a basic target reaction-force based on the operating position, a target reaction-force compensating part for computing a reaction-force compensation-amount based on the improper-halt state and the operating position, a target reaction-force computing part for computing a target reaction-force based on the basic target reaction-force and reaction-force compensation-amount, and an assist force computing part for computing an assist force based on the target reaction-force and operating force.

Abstract: An operating position select device includes a select lever unit having a select lever, an operating position sensor detecting an operating position of the lever, a mode shift unit of an automatic transmission, a shift position sensor detecting a shift position of the mode shift unit. A mechanically connecting means connects the lever and the mode shift unit. A control unit controls an assist actuator arranged between the lever and the mode shift unit for assisting the lever. The connecting means has a torque transmittable adjuster at its intermediate part, and it has play for changing its length and an elastic member disposed into the play so as to transmit force through the torque transmittable adjuster.

Abstract: An operating position select device has a select lever unit, a mode shift unit to shift operation modes of the automatic transmission, a mechanically connecting means connecting them, and an assist actuator to assist a select lever. A control unit that controls the actuator is electrically connected to an operating position sensor detecting an operating position of the select lever and an operating velocity detector detecting operating velocity of the lever. The control unit includes a target reaction-force characteristic setting part, a feedback control part determining feedback assist force by multiplying gain by a variation between target reaction force obtained based on the target operating reaction-force characteristic and the operating force obtained based on the operating force signal, and a gain changing part that changes gain used for determining the feedback assist force based on the operating speed signal.

Abstract: An operating position select device has a select lever unit, a mode shift unit to shift operation modes of the automatic transmission, a mechanically connecting means connecting them, and an assist actuator to apply assist force to a select lever of the select lever unit. A control unit for controlling the actuator is electrically connected to an operating state sensor detecting an operating state of the select lever. The control unit executes assist control to control the assist actuator based on the operating state signal of the operating state sensor, and maintains the assist control for a predetermined period after the ignition switch is turned to OFF.

Abstract: 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.

Abstract: A control unit (41) controls an opening of an exhaust recirculation valve (6) according to a running condition of a diesel engine (1). The control unit (41) calculates an equivalence ratio of the gas mixture supplied to the engine (1) and a target intake fresh air amount taking account of the air amount in the exhaust gas recirculated by the exhaust gas circulation valve (6), based on the opening of the valve (6) and a target excess air factor of the engine (1) set according to the running condition. By controlling a turbocharger (50) according to the target intake fresh air amount, and by controlling the fuel supply mechanism according to a fuel injection amount calculated from the equivalence ratio, the excess air factor of the engine (1) and an exhaust gas recirculation rate of the exhaust gas recirculation valve (6) are respectively controlled to optimum values.

Abstract: 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.

Abstract: 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 (30). 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 (16) and the target fresh air intake amount tQac by the basic target excess air factor tLAMBDA0. A fuel injector (9) 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 (30) 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.

Abstract: 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=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.

Abstract: 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.

Abstract: A control unit (41) controls an opening of an exhaust recirculation valve (6) according to a running condition of a diesel engine (1). The control unit (41) calculates an equivalence ratio of the gas mixture supplied to the engine (1) and a target intake fresh air amount taking account of the air amount in the exhaust gas recirculated by the exhaust gas circulation valve (6), based on the opening of the valve (6) and a target excess air factor of the engine (1) set according to the running condition. By controlling a turbocharger (50) according to the target intake fresh air amount, and by controlling the fuel supply mechanism according to a fuel injection amount calculated from the equivalence ratio, the excess air factor of the engine (1) and an exhaust gas recirculation rate of the exhaust gas recirculation valve (6) are respectively controlled to optimum values.

Abstract: 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=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.

Abstract: 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.

Abstract: 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 (30). 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 (16) and the target fresh air intake amount tQac by the basic target excess air factor tLAMBDA0. A fuel injector (9) 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 (30) 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.

Abstract: 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.

Abstract: A fuel injection control system is arranged to decide the execution of a pilot fuel injection based on evaluation functions indicative of degree of a pilot fuel injection demand, to decide an engine operating condition, to calculate a fuel injection quantity for each cylinder when the engine operating condition is in the predetermined low-load operating region, to calculate a pilot fuel injection quantity for each cylinder by multiplying a predetermined ratio to the fuel injection quantity in the predetermined low-load operating region and when the pilot fuel injection is executed, and to calculate a main fuel injection quantity by subtracting the pilot fuel injection quantity from the fuel injection quantity. Therefore, this arrangement enables accurate decision as to the execution of the pilot fuel injection and proper control of pilot and main fuel injection quantities.