摘要:
A continuously variable transmission (CVT) for use in a vehicle is controlled such that an actual engine speed Ne is equalized to a desired engine speed No. When a driver's request for a rapid speed change of the vehicle is addressed, a desired engine speed Ns for steady state or the desired engine speed No before the request is detected is defined as a first value Nc1. While the request continues the desired engine speed Ns for steady state which is determined by current values of vehicle running parameters is defined as a second value Nc2. The product B.multidot.(Nc2-Nc1) of a constant B and Nc2 minus Nc1 is calculated and defined as a desired engine speed during the request.
摘要:
A diagnostic apparatus for a continuously variable transmission the speed ratio and/or the rate of variation in the speed ratio of which are controlled by a shift-regulating device controlled by command signals from a control system. The diagnostic apparatus, which checks if the speed ratio is normally controlled, comprises: a detecting device for detecting an actual speed ratio and/or an actual rate of variation in the speed ratio; a memory storing data for determining normal ranges of the speed ratio and/or normal ranges of the rate of variation in the speed ratio, the normal ranges corresponding to shifting conditions of the transmission which are established by the shift-regulating device according to the command signals; and a judging device for selecting one of the normal ranges of the speed ratio, and/or one of the normal ranges of the rate of variation in the speed ratio, based on the command signals, the judging device checking whether the detected actual speed ratio and/or the detected actual rate of variation in the speed ratio fall within the selected normal ranges.
摘要:
A hydraulic pressure control device for an automatic transmission for a vehicle, including a spool type hydraulic pressure control valve for selectively prevent setting up of the reverse stage when a manual shift valve is set to the reverse range while the vehicle is traveling forward, wherein the spool element of the hydraulic pressure control valve is positively shifted to a position for not preventing the setting up of the reverse stage by a hydraulic pressure available when the manual shift valve is set to the forward range.
摘要:
For an automatic transmission for a vehicle such as an automobile having a first friction engaging means such as a clutch which is switched over between engagement and disengagement between two adjacent speed stages such as the third speed stage and the fourth speed stage and a second friction engaging mechanism such as a brake which is engaged at two spaced apart jumping apart speed stages such as the fourth speed stage under D range and the second speed stage under S range, a hydraulic control device switches over such two friction engaging means by a first shift valve for three speed stages such as the fourth, third and second speed stages with a help of second shift valve for switching over the second speed stage and the third speed stage. A drain port of the first shift valve is supplied with a hydraulic pressure from an S port of a manual shift valve through the second shift valve.
摘要:
A hydraulic control system for a continuously variable transmission having a cylinder for changing the effective diameter of a pulley to control a speed ratio of the transmission. The control system comprises a spool valve assembly communicating with the cylinder to control the supply and discharge flows of a fluid to and from the cylinder. The valve assembly comprises a shift-speed control valve unit for controlling a rate of variation in the speed ratio of the transmission. The shift-speed control valve unit has only two discharge ports associated with the fluid discharge from the cylinder. The shift-speed control valve unit may take the form of a spool valve having a spool axially movable to open and close the ports to permit and restrict the fluid flows through supply and discharge conduits communicating with the ports and the cylinder. The spool may only partially open the corresponding port to permit the fluid flow therethrough for supplying or discharging the fluid. The valve assembly may comprise a shift-direction switching valve unit for changing the direction in which the speed ratio is varied. The switching valve unit has only two discharge ports associated with the fluid discharge from the cylinder.
摘要:
A method for controlling a continuously variable transmission installed in a vehicle. The method controls the continuously variable transmission such that the desired engine speed or the desired transmitting speed ratio of the transmission may be determined to be a function of a throttle opening or a pressure within an intake pipe and a vehicle speed.
摘要:
An apparatus for controlling an continuously variable transmission (CVT) used for a power transmission system of a vehicle. The CVT is controlled such that an actual engine speed becomes a desired engine speed. The desired engine speed is set as a function of running parameter such as intake throttle position. When the CVT is controlled in the same way as at the steady state of the vehicle at the acceleration of the vehicle, the acceleration performance is degraded. Thus, according to the present invention, the speed ratio of the CVT is reduced when the acceleration of the vehicle is small, in spite of the requisition of the vehicle acceleration. As a result, satisfactory drivability is attained.
摘要:
A hydraulic control device for generating a hydraulic pressure for a back pressure chamber of an accumulator in a speed stage shifting device of an automatic transmission for a vehicle such as an automobile is adapted to generate a hydraulic pressure to be supplied to the back pressure chamber of the accumulator by modulating the so-called line hydraulic pressure according to a balance between the modulated pressure itself and the line hydraulic pressure or more desirably an engine power simulation pressure modulated from the line hydraulic pressure to be lower than the line hydraulic pressure in low engine output operation under an influence of a signal hydraulic pressure controlled by an electromagnetic valve, wherein the signal hydraulic pressure decreases to substantially zero when the electromagnetic valve fails, and the accumulator control valve has a spool element having a first pressure receiving area exposed to the modulated hydraulic pressure to generate a positive feedback effect of decreasing the modulated hydraulic pressure along with increase thereof and a second pressure receiving area so that the accumulator control valve variably operates even when the signal pressure has decreased to zero exposed to the line hydraulic pressure or the engine power simulation pressure to generate an effect of increasing the modulated pressure, the first pressure receiving area having an effective pressure responsive sectional area substantially equal in the magnitude and opposite in the orientation to that of the second pressure receiving area.
摘要:
A hydraulic control device having a reverse inhibition system and applicable to an automatic transmission for a vehicle of a type including a friction engaging means for a reverse stage having a reverse exclusive hydraulic pressure chamber adapted to be supplied with a hydraulic pressure only for setting up the reverse stage, the reverse inhibition system having a reverse inhibition valve biased to a reverse inhibition position by a control hydraulic pressure for interrupting supply of hydraulic pressure to the reverse exclusive hydraulic pressure chamber and to a reverse allowance position by a hold hydraulic pressure for allowing the supply of hydraulic pressure to the reverse exclusive hydraulic pressure chamber, wherein the hydraulic pressure supplied to the reverse exclusive hydraulic pressure chamber is used for the hold hydraulic pressure.
摘要:
A hydraulic control apparatus for controlling a frictional coupling device of an automatic transmission for a motor vehicle includes a shift valve for effecting an engaging action of the coupling device from a first position to a second position, and an accumulator for reducing a change in a hydraulic pressure applied to the coupling device. The control apparatus is adapted to control a control value to regulate a back pressure of the accumulator, based on a parameter associated with an output of an engine, and according to a predetermined relationship between the control value and the parameter, so as to reduce a shifting shock of the transmission. The control apparatus includes a detector for detecting an engaging time of the engaging action of the coupling device. The control apparatus further includes a compensating device for updating the relationship between the control value and the parameter, depending upon the detected engaging time, with respect to a specific value of the parameter at which the engaging action takes place. The compensating device maintains the updated relationship for use for a subsequent engaging action of the coupling device from the first position to the second position.