Abstract: An apparatus and method for performing a kiss point determining algorithm which is responsive to the approach rate of the release bearing of a clutch for performing the algorithm only under reliable operating conditions. The apparatus includes an electronic controller which sets an approach rate for engaging the clutch in response to the amount of depression of the accelerator pedal of the vehicle by the operator. The amount of engine torque or other engine operating condition is measured and compared against a predetermined magnitude which is indicative of the onset of engagement of the clutch. When an increase of a predetermined magnitude is detected, the accelerator pedal position is compared against a predetermined value. If the accelerator pedal is depressed more than the predetermined value, the kiss point is re-defined as the current location of the release bearing. If the accelerator pedal is not depressed more than the predetermined value, the kiss point is not re-defined.

Abstract: An apparatus and method for controlling the rate of engagement of a clutch in response to an indication provided by the driver, such as the depression of an accelerator pedal of the vehicle. The apparatus includes an electronic controller which initially determines a start rate as the minimum duty cycle which is required to modulate an engage valve in order to cause movement of a release bearing of the clutch in the engagement direction. Following the receipt of a signal from the operator of the vehicle to initiate the engagement of the clutch, the electronic controller calculates an initial transition rate of movement of the release bearing from a disengaged position to a transition point. The transition rate is determined as a function of the start rate and a position error signal. The position error signal can be calculated as the difference between the actual position of the release bearing and the transition point.

Abstract: An electronic controller for use in a partially or fully automatic vehicle transmission. The transmission includes an automatic shifting mechanism for partially or fully automating the shifting thereof to select and engage gear ratios. The automatic shifting decisions are made by an electronic control circuit including an electronic controller which receives electrical signals representative of the rotational speeds of the input and output shafts of the transmission. An algorithm is performed by the electronic controller to identify the structure of the underlying transmission and adopt an appropriate shifting strategy based upon the rotational speeds of the input and output shafts of the transmission. Initially, the electronic controller determines if the transmission is, in fact, engaged in a gear ratio. Once it has been determined that the transmission is engaged in a gear ratio, the electronic controller determines what the specific magnitude of that gear ratio is.

Abstract: A clutch actuator includes an outer cylinder housing having a plurality of ramps formed on an inner cylindrical surface thereof. Each of the ramps has a radially inwardly facing surface which includes a forwardly facing tapered surface and a rearwardly facing tapered surface. A hollow cylindrical piston is disposed concentrically within the outer cylinder housing and has a plurality of axially extending protrusions formed thereon. Preferably, the number of such protrusions is equal to the number of the ramps formed on the outer cylinder housing, and the protrusions are circumferentially interleaved within the ramps formed on the outer cylinder housing. Each of the protrusions has a radially outwardly facing surface which includes a forwardly facing tapered surface and a circumferentially extending groove. An inner cylinder housing is disposed concentrically within the piston.

Abstract: An interlock assembly for a vehicle transmission prevents more than one of a plurality of shift rails from being simultaneously moved axially out of a central neutral position to a gear engaging position. The interlock assembly includes an interlock plate having four semi-circular cut-outs (one for each of the shift rails) and two relative large interior openings. The interlock assembly further includes a backing plate which is somewhat smaller than the interlock plate and has two relatively small interior openings. A pair of threaded fasteners extend through the small openings of the backing plate and through respective spacer bushings disposed in the large interior openings of the interlock plate into threaded engagement with the housing of the hydraulic actuator. The spacer bushings prevent the interlock plate from being frictionally engaged between the backing plate and the housing of the hydraulic actuator.

Abstract: A transmission includes a plurality of shift rails, each of which is axially movable forwardly and rearwardly from a center neutral position to respective gear engaging positions. The lower shift rails are provided for manual shifting among the lower gear ratios of the transmission. The highest shift rail is provided for selective manual or automatic shifting among the highest two gear ratios of the transmission. An idler rail is disposed adjacent to the highest shift rail. For manual shifting, the idler rail is connected to the highest shift rail, and a manually operable shift lever is used to move both the idler rail and the highest shift rail. For automatic shifting, the idler rail is disconnected from the highest shift rail, and an automatic shift member is moved into cooperation with the highest shift rail. Rotation of the automatic shift shaft causes corresponding movement of the automatic shift member.

Abstract: A transmission includes a plurality of shift rails, each of which is axially movable forwardly and rearwardly from a center neutral position to respective gear engaging positions. The lower shift rails are provided for manual shifting among the lower gear ratios of the transmission. The highest shift rail is provided for selective manual or automatic shifting among the highest two gear ratios of the transmission. An electronic controller is provided for controlling the automatic shifting of the transmission in response to sensed operating conditions of the vehicle. A circuit is provided for sensing the rotational position of the automatic shift shaft and for generating an electrical signal which is representative of the actual position thereof, which is also representative of the actual position of the highest shift rail, to the electronic controller. The transmission also includes a shift lever having an end which extends through an opening formed in a case.

Abstract: A transmission includes a plurality of shift rails, each of which is axially movable forwardly and rearwardly from a center neutral position to respective gear engaging positions. The lower shift rails are provided for manual shifting among the lower gear ratios of the transmission. The highest shift rail is provided for selective manual or automatic shifting among the highest two gear ratios of the transmission. An idler rail is disposed adjacent to the highest shift rail. For manual shifting, the idler rail is connected to the highest shift rail, and a manually operable shift lever is used to move both the idler rail and the highest shift rail. For automatic shifting, the idler rail is disconnected from the highest shift rail, and an automatic shift member is moved into cooperation with the highest shift rail. Rotation of the automatic shift shaft causes corresponding movement of the automatic shift member.

Abstract: An improved release mechanism for a hydraulically operated clutch. A tubular cylinder is formed between stationary inner and outer housings. A tubular piston has an inner end extending into the cylinder and has an outer end mounting a thrust bearing. Rotating clutch release levers engage the thrust bearing. One or more radial holes extend through the piston adjacent the inner end. Pins positioned in the holes extend into inner housing grooves which extend parallel to an axis of the release mechanism. The pins and grooves prevent rotation of the piston relative to the stationary housings, while allowing axial piston movement. A retainer ring is positioned in an annular groove in the exterior of the piston. The retainer ring both retains the pins in the piston holes and retains the piston in the cylinder.

Abstract: A vehicle mechanical transmission includes a conventional shift lever which enables the vehicle driver to manually select lower gear ratios, and an automatic shifting mechanism which provides automatic shifting between selected higher ratios once the driver has moved the shift lever to an "automatic" position. The transmission includes a plurality of shift rails which are individually and selectively moveable from a neutral position to two different gear positions. In accordance with the present invention, the shift lever is only coupled to mechanically shift a portion of the shift rails, typically those shift rails corresponding to the lower gear ratios. Once all the lower ratios have been selected, the driver can move the shift lever to an "automatic" position. When in this position, the shift lever actuates an electronic control, which in turn automatically controls the shifting of at least one shift rail in accordance with the status of various monitored vehicle operating parameters.

Abstract: A hill holder device for a vehicle manual transmission includes a releasable one-way clutch which is coupled to the countershaft of the transmission. In particular, the one-way clutch includes a sprag clutch having an inner race secured to the countershaft, and an outer race secured to the vehicle transmission case by means of a releasable locking mechanism. When the locking mechanism is in its locked position, the sprag clutch enables rotation of the countershaft in only one direction. Thus, if the transmission is in a forward gear and comes to a stop on an ascending grade, the hill holder will lock the vehicle drive train and prevent the vehicle from rolling back down the grade, without requiring the driver to apply the brakes. Similarly, if the vehicle is in a reverse gear and is stopped on a descending grade, the hill holder will prevent the vehicle from rolling in a forward direction down the grade.