Abstract: A control system of a vehicular continuously variable transmission having a manual transmission mode comprises speed ratio changing when a manual transmission mode is chosen and a speed range is manually selected for changing a speed ratio of the selected speed range in the up-shift direction as the engine speed becomes high on the side of low speed ranges and in the down-shift direction as the vehicle speed becomes high on the side of high speed ranges. Further, in the manual transmission mode, when the engine speed reaches a lower limit value without making a down-shift, the speed ratio is controlled so as to hold the engine speed at the lower limit value. Thus constituted continuously variable transmission provides a vehicle with miscellaneous advantages such as an easy handling, smooth acceleration/deceleration performance, extended maximum speed and the like when the manual transmission mode is selected.

Abstract: When a speed ratio is selected manually by an operator of a vehicle, an upshift command is generated if the engine speed exceeds a predetermined maximum value. Further manual upshifts and downshifts are inhibited for a predetermined time period. The time period is a function of at least one of the current engaged gear ratio, engine throttle position, and the amount of time it takes to upshift the transmission.

Abstract: A control system and method for a semi-automatic mechanical transmission system (10) is provided for allowing operator request for direct shifts into a preselected default start ratio (GR.sub.DS) or into a dynamic best gear ratio (GR.sub.DB) under certain predefined conditions. The dynamic best gear ratio, under at least certain vehicle operating conditions, is the higher of a test best gear ratio (GR.sub.TB =ES.sub.TARGET /OS), determined as a function of vehicle speed (OS) and a target engine speed (ES.sub.TARGET), or the default start ratio.

Abstract: A degraded mode of operation (FIG. 7) for a partially automated mechanical transmission system (92) having a splitter-type mechanical transmission (10) with a splitter section (14) automatically shifted in only certain ratios (ninth/tenth). Upon sensing certain system faults when in this automatic splitter shifting mode, the splitter section is retained, as is, until main section neutral can be confirmed, at which time the splitter section is returned to manual control for all transmission ratios.

Abstract: A control method/system for controlling engagement of reverse ratios in automated vehicular transmission systems (10) having a controller (38) issuing command output signals to non-manually controlled actuators (30, 34) is provided. The controller includes logic rules for (i) sensing predetermined reverse ratio enabling conditions, including remaining in neutral for at least a predetermined period of time (N.sub.T >REF.sub.2) prior to selecting reverse, and (ii) issuing commands to cause a reverse ratio to be engaged only upon sensing such conditions, to minimize accidental engagement of reverse ratios without requiring mechanical interlocks.

Abstract: A control and control method for a semi-automatic mechanical transmission system (10) is provided for sensing operator request for a direct downshift into an optimum pull-away ratio and for automatically determining and engaging the optimum pull-away ratio. The optimum pull-away ratio (GR.sub.PULL-AWAY) is adaptively selected as a function of throttle position (THL>REF.sub.THL).

Abstract: A partially automated mechanical transmission system (92) having a mechanical transmission (10) with a lower group (first-eighth) of manually shifted ratios and an upper group (ninth-tenth) of ratios with automatic shifting between ratios in the upper group and requiring manual shifting between groups. Control logic is provided to sense a driver intention to shift into the automated upper group of ratios and to initiate automatic engine synchronizing for engagement of one of said ratios in said upper group.

Abstract: A partially automated mechanical transmission system (92) includes a splitter-type compound transmission (10) and controls for automating splitter shifting upon manual selection of the highest main section ratio position (ninth/tenth). Logic is provided to provide an optimized response to manual shifting into main section neutral from the highest main section ratio position.

Abstract: A control system and method for controlling start-from-stop operation in an automated mechanical transmission system, including a multiple-speed change-gear transmission (10) having a lowest grouping of ratios (first-fourth) suitable for start-from-stop operation, is provided. Upon a request or requirement for a shift into a default start ratio, the system controller (106) will cause initiation of a shift into the highest gear ratio (fourth) of the lowest group of ratios.