Nissan Motor Company Limited

Yuji Kobari

Takashi Imaseki

Eiji Yagi

Yukiyoshi Hatori

Kiyotaka Ozaki

Sadahiro Takahashi

Shuuji Torii

Keiichi Miyamoto

A positive-displacement type pump system, such as a fixed-cylinder type radial piston pump system, includes a common pump housing formed with a plurality of cylinders, and a plurality of pistons slidably received in the respective cylinders and cooperating therewith to form a plurality of pump units. A first throttle valve is disposed in a first suction passage of a first group of the pump units for operating a first actuator, for adjusting the flow rate of a working fluid to be supplied to the these pump units. A second throttle valve is disposed in a second suction passage of a second group of the pump units for operating a second actuator, for adjusting the flow rate of the working fluid to be supplied to the pump units of the second group independently from those of the first group. The pump units of the first and second groups can thus be individually adjusted in terms of the respective delivery volumes.

Positive-displacement type pump system

A differential limiting force control system for controlling a slip limiting force by controlling an engagement force of a clutch assembly of a limited slip differential provided between left and right drive wheels of a vehicle includes a control unit having a basic control section for increasing the differential limiting force with increase of a vehicle speed, and an adjusting section for decreasing the differential limiting force when a steering angle is equal to or lower than a predetermined angle, or when a steering angular speed is equal to or higher than a predetermined angle.

Differential limiting force control system responsive to vehicle speed

A differential is provided with a clutch variable in engagement for producing a slip limiting force for limiting a differential action even during cornering of a vehiocle. A force for urging the clutch for engagement is reduced for thereby reducing the slip limiting force in response to increase of a driving wheel slip during cornering of the vehicle.

Slip control device for differential

A control system for controlling a differential limiting force of a limited slip differential of a vehicle includes a section for sensing a turning radius of the vehicle, a section for sensing centripetal acceleration of the vehicle, and a controller section. The controller section increases an engagement force of a differential limiting clutch of the limited slip differential in accordance with the turning radius and the centripetal acceleration.

Limited-slip differential control system

A differential limiting torque control system for a vehicle includes a differential limiting clutch provided in a differential, a sensing section including sensors such as an accelerator position sensor, and sensors for sensing speeds of left and right front wheels and left and right rear wheels, and a control unit controlling a differential limiting torque of the differential limiting clutch in accordance with an accelerator opening degree of movement, a left and right drive wheel speed difference, and a drive wheel slip which is represented, for example, by a front and rear wheel speed difference, in such a manner that the differential limiting torque is held equal to a difference obtained by subtraction whose subtrahend is a quantity proportional to the drive wheel slip, and whose minuend is a sum of a quantity proportional to the accelerator opening degree and a quantity proportional to the left and right drive wheel speed difference. The control unit may further control the differential limiting torque in accordance with a lateral acceleration in such a manner that the subtrahend is decreased with increase of the lateral acceleration.

Vehicular differential limiting torque control system

A four-wheel steer control device has an actuator for actuating a set of steerable rear wheels for controlling the positions of the rear wheels by the operation of the actuator. A slip control device for a differential has a clutch for supplying a variable slip limiting force to the differential to limit a differential action thereof variably. An integrated control system controls the four-wheel steer control device and the slip control device in such a way that the rear wheels are correctively steered in the direction opposite to that of the front wheels at the time of cornering of the vehicle and when the slip limiting force is larger than a predetermined value and a cornering outside driving wheel speed is faster than a cornering inside driving wheel speed.

Integrated four-wheel steer and differential slip control system

An integrated roll rigidity and differential slip control system for a wheeled vehicle comprises roll rigidity changing means for changing roll rigidity distribution to front and rear wheel sides, roll rigidity control means for controlling the operation of said roll rigidity changing means based on vehicle running conditions, a differential interposed between the rear wheels, clutch means for supplying a slip limiting force to the differential to limit differential action thereof, and slip control means for controlling engagement of the clutch means based on vehicle running conditions and integrated control means for controlling, in preference to the control by the roll rigidity control means, the roll rigidity distribution in such a way that a roll rigidity is larger on the front wheel side and smaller on the rear wheel side in response to a cornering condition in which a driving force is distributed more to a cornering outside driving wheel than to a cornering inside driving wheel.

Integrated roll rigidity and differential slip control system

A four wheel drive system of a vehicle has a transfer clutch capable of varying clutch torque transmitted therethrough from an engine to front wheels. The clutch torque is controlled by a driving force distribution control unit in accordance with a front and rear wheel speed difference determined from signals from front and rear wheel speed sensors. Preferably, the control unit controls a distribution ratio of a front wheel driving force to a rear wheel driving force by controlling the clutch torque of the transfer clutch in such a manner that the distribution ratio decreases as the wheel speed difference increases when the wheel speed difference is positive, that is the front wheel speed is higher than the rear wheel speed, and that the distribution ratio increases as the absolute value of the wheel speed difference increases when the wheel speed difference is negative.

Four wheel drive system having driving force distribution control

A four wheel drive motor vehicle is equipped with a change-over unit for selecting a four wheel drive mode or a two wheel drive mode, a road surface condition sensing sonar system, and an actuator for actuating the change-over unit to change the drive system to the four wheel drive mode when the road surface condition sensing system determines that the road surface is slippery. The road surface condition sensing means has ultrasonic transmitter and receiver, and a control unit such as a microcomputer for determining whether the intensity of waves reflected from the road surface is equal to or lower than a predetermined value.

Part time four wheel drive vehicle with road surface condition sensor

A vehicular power steering system has on/off control means for controlling a hydraulic fluid pump in accordance with steering effort applied on a steering wheel. On the other hand, a sensing means senses vehicle speed. Judging means is connected with the on/off control means and the vehicle speed sensing means, and produces an actuating signal when the control means produces a control signal to drive the fluid pump and at the same time the sensed vehicle speed is below a predetermined speed. A solenoid valve is connected with the judging means. The solenoid valve is arranged to open and close a bypass passage which allows an air fuel mixture to bypass a throttle valve for an intake air flow control of the engine. Thus, the supply of an air fuel mixture to the engine is increased in response to the actuating signal, and the engine idling speed is stabilized.

System for stabilizing idling of vehicular engine

A pump-drive device of a power-assisted vehicle steering system, comprising a motor operative to drive a steering pressure pump, a first sensor for detecting vehicle speed and producing an output signal representative of the detected vehicle speed, a second sensor for detecting the motor output speed and producing an output signal representative of the detected motor output speed, a current control circuit responsive to the output signals from the first and second sensors, a main current supply line connected between a power source and the motor through the current control circuit, a bypass current supply line bypassing the current control circuit between the power source and the motor, the current control circuit being operative to produce an output signal to vary the current to be passed through the main current supply line on the basis of the output signals from the first and second sensors, a detecting unit responsive to a predetermined operative condition of the steering system and operative to produce an output signal when the steering system is in the predetermined operative condition, and a line shifting switch unit to provide electrical connection selectively between the power source and the motor selectively through the main and bypass current supply lines in the absence and presence, respectively, of the output signal from the detecting unit.

Pump-drive device of power-assisted steering system

A sensor arrangement features a rolling element and cam groove arrangement which induces a displacement via which a switch may be closed to indicate that torque is being applied via a steering wheel to an upper section of a steering shaft arrangement and which provides an essentially instantaneous drive connection between the upper and a lower section of the steering shaft arrangement thus maintaining a desirable degree of torsional rigidity.

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Zushi, Japan

Yuji Kobari