Nissan Motor Company Limited

Keiju Abo

Sigeaki Yamamuro

Hiroyuki Hirano

Haruyoshi Kumura

Yoshikazu Tanaka

Yoshiro Morimoto

Masaki Nakano

Hideaki Takahara

Shojiro Kuroda

Osamu Sato

Hideaki Suzuki

Masahiro Yamamoto

Toshikazu Oshidari

An engine and a motor are connected to the drive wheels of a vehicle via an automatic transmission. The drive wheels are driven using one of or both of the motor and the engine depending on the running state. The automatic transmission varies the drive ratio by the discharge pressure of the oil pressure pump. The oil pressure pump is driven by a second motor. When the automatic transmission is varying the drive ratio, the discharge of the oil pressure pump is increased by increasing the rotational speed of the second motor and thus the required oil for varying the drive ratio is maintained.

Oil pressure supply device for vehicle drive system

An electronic transmission control system for an automotive vehicle with a belt-type continuously variable automatic transmission comprises a transmission ratio control device including a first motor-driven oil pump supplying working pressure directly to a secondary pulley actuation chamber, and a second motor-driven oil pump supplying working pressure directly to a primary pulley actuation chamber and enabling working oil to come and go between the primary and secondary pulley actuation chambers therethrough. A first control section is provided for controlling the first motor-driven oil pump so that the actual secondary pulley pressure is adjusted to a target working pressure needed to hold a belt capacity of a drive belt, which belt capacity is defined as a capacity required for exerting a grip of the drive belt on primary and secondary pulleys. Also provided is a second control section which controls the second motor-driven oil pump by limiting a speed-change flow rate (or a speed-change velocity), so that the actual primary pulley pressure is prevented from reducing to below a lowest working pressure capable of holding the belt capacity.

Electronic transmission control system for automotive vehicle with continuously variable automatic transmission

An electronic transmission control system for an automotive vehicle with a belt-type continuously variable automatic transmission comprises a transmission ratio control device including a first motor-driven oil pump supplying working pressure directly to a secondary pulley actuation chamber, and a second motor-driven oil pump supplying working pressure directly to a primary pulley actuation chamber and enabling working oil to come and go between the primary and secondary pulley actuation chambers therethrough. A first control section is provided for controlling the first motor-driven oil pump with feed-forward compensation for the working pressure supplied to the secondary pulley actuation chamber, based on changes in a flow rate of the working oil coming and going between the primary and secondary pulley actuation chambers, so that the secondary pulley pressure is regulated as a belt capacity holding pressure needed to hold a belt capacity of the drive belt in a first motor-driven pump side. Also provided is a second control section controlling the second motor-driven oil pump, so that the primary pulley pressure is regulated as a belt capacity holding pressure needed to hold a belt capacity of the drive belt in a second motor-driven pump side and so that a required value of a speed-change flow rate of the working oil coming and going between the primary and secondary pulley actuation chambers is obtained.

An antilock brake system which decreases a braking pressure to prevent drive wheels from locking is applied to a hybrid vehicle wherein an engine and a motor are connected to the drive wheels via a continuously variable transmission. The rotation torque of a motor is applied to the drive wheels when the braking pressure is reduced due to antilock control so that the engine braking force which acts during braking does not interfere with antilock control.

Vehicle drive system controller and control method

A motor/generator and drive wheel are connected to an engine, and the drive wheel is driven by the engine and motor/generator according to running conditions. A sensor which detects a slip of the drive wheel and a sensor which detects a depression of an accelerator pedal are provided, and the motor/generator is operated as a generator when the accelerator pedal is depressed and the drive wheel has slipped. Further, a spin of the drive wheel is prevented by increasing the rotation resistance of the motor/generator according to the frictional coefficient of the road surface.

Vehicle drive device and vehicle drive device control method

An engine and generator/motor are connected to the input shaft of a continuously variable transmission, and the output shaft of the continuously variable transmission is connected to drive wheels. A target value of a coasting torque acting on the output shaft during coasting is set according to a vehicle speed. A real coasting torque is estimated from the output torque of the engine and frictional torque of the continuously variable transmission. By making the generator/motor function as a generator or a motor, fluctuation of the engine braking force due to a variation of drive ratio during coasting is suppressed so that the real coasting torque coincides with the target value.

In order to improve steering performance and braking performance specifically on a low .mu. road surface during operation of engine braking, there are provided, in a shift control system of a continuously variable transmission, a sensor for determining a wheel deceleration, and a shift controller for changing a shift pattern adequately. When an engine brake range such as a 2 range or an L range is selected, and the wheel deceleration becomes greater than a predetermined deceleration level, the shift controller changes an upshift limit of the engine brake range, to a smaller transmission ratio. By reducing the transmission ratio in this way, the shift control system can reduce an engine braking force applied to the drive wheels and an inertia torque of the transmission against the driving force applied to the drive wheels by the road surface, so that the wheel speed can readily increase to achieve a desirable degree of wheel slip.

System for controlling a continuously variable transmission in response

A hybrid continuously variable transmission includes a clutch which effects a shift from a power train through a gearing mechanism to another power train through a continuously variable transmission mechanism. A duty soleonid is provided to control the supply of hydraulic fluid to and discharge thereof from the above-mentioned clutch under the control of a control unit.

Hybrid continuously variable transmission with electronically controlled

A control system for a transmission is disclosed. The control system includes a high clutch and a low clutch. When the high clutch is engaged, the torque transmission path through a V-belt type continuously variable transmission mechanism is established, while when the low clutch is engaged, the torque transmission path through a gearing mechanism is established. The same hydraulic fluid pressure as prevailing in a driver pulley cylinder chamber is admitted to the high clutch directly or via a suitable selector valve (a neutral valve).

Control system for transmission

A power transmission belt adapted for use in a pulley transmission, comprises a plurality of chains which are arranged in parallel with their pins of each chain positioned out of alignment with the pins of the adjacent chain, and a plurality of load blocks surrounding said plurality of chains. The load blocks functions to provide positive interference among vibrations of the chains so that the amplitude of vibration of the whole assembly is reduced.

Power transmission belt

After the throttle opening degree has exceeded a predetermined value, a target value in engine speed that varies in correspondance with the throttle opening degree is modified to vary in a second pattern whereby the continuously variable transmission is shifted to a predetermined reduction ratio and then kept operating at the predetermined reduction ratio so as to allow the engine speed to increase with the variation in vehicle speed, thus providing an increased acceleration feel.

Method of controlling continuously variable transmission

The invention provides an apparatus wherein a parameter indicative of the actual position of a shift actuator is reset periodically when the transmission shift to the largest reduction ratio by such operation is prevented when the vehicle speed is greater than a predetermined vehicle speed value, such as 10 km/h.

Apparatus for controlling reduction ratio in continuously variable

A control device for an automatic transmission comprises an electromagnetic valve that is subject to pulse duty factor control and generates an adjustment pressure variable in a first pattern after a rod of a shift operation mechanism has moved into an overstroke range beyond a maximum reduction ratio position. The adjustment pressure is variable in a second pattern when the rod fails to move into the overstroke range. An adjustment pressure change-over valve is formed integral with the rod and applies the adjustment pressure to a servo actuating pressure regulator valve (i.e., a throttle valve) when the motor vehicle is at a standstill and the engine idles so as to effect a creep torque control. When the motor vehicle starts moving at a speed above a certain vehicle speed, the adjustment pressure change-over valve applies the adjustment pressure to a lock-up control valve, thereby to effect a lock-up control.

Creep torque and lock-up control for automatic transmission

A transmission belt is disclosed wherein a plurality of push elements are arranged on a carrier such that a difference in radial distance of guide surface between the adjacent two push elements is not greater than a predetermined value in order to keep the push elements into contact with an inner surface of the carrier.

Transmission belt provided with push elements

In a line pressure control device for a hydraulic control system of an automatic transmission, a vacuum diaphram unit is constructed to apply upon a valve spool of a throttle valve or a regulator valve such a force that reduces with increasing intake manifold vacuum when the intake manifold vacuum is lower than a first predetermined value and such a force that increases with increasing intake manifold vacuum when the intake manifold vacuum is higher than a second predetermined value.

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Yokosuka, Japan

Keiju Abo