Rockwell International Corporation

Detroit Diesel Corporation

Meritor Heavy Vehicle Systems Limited

Edward M Bacon

Thomas P Desautels

Steve M Weisman

Jon M Huber

Charles E Allen, Jr

Steven E Radue

Christopher S Keeney

Frank A Palmeri

A dithering torque control method that is useful for a semi-automated vehicle transmission facilitates accomplishing a desired condition in the transmission. The method is useful during an initial break torque function to relieve drive train torque so that a driver can move a manual shift lever from an engaged position to a transmission neutral position without using a clutch. The method is also useful for shifting a lever to move gearing components from a neutral position to a next desired gear. A dithering function is used to cyclically oscillate a current torque value about a target torque value that is associated with the desired transmission condition. An amplitude and period of the dithering function are determined based upon an overall gear ratio of the transmission. The dithering function begins at a point dependent on a torque value associated with the currently engaged gear. The dithering function continues until a known transmission condition is confirmed.

Torque dithering method for controlling a vehicle transmission

An improved switch system is incorporated into a multi-speed transmission and engine combination. The switch system provides a positive electronic signal to an electronic control unit for the engine of both when the transmission is in a neutral state and when the transmission is in a gear-engaged state. In one embodiment, a switch plunger rides within a switch housing between two extreme positions. The switch plunger is at one axial position when the transmission is in neutral, and at the other axial position when the transmission is in a gear-engaged state. At either position, an electric circuit is completed and a signal is sent to an electronic control unit. The electronic control unit is thus provided with positive position feedback for the transmission. The electronic control unit will preferably also have the ability to control the engine speed to synchronize the engine speed with a desired engine speed for the next selected gear ratio to achieve synchronization between the speeds when the shift if completed. The electronic control unit does not begin to modify the engine speed until it has received a positive signal that the transmission is in neutral.

Two-position neutral switch for multi-speed transmission

An improved engine control provides rapid decrease in the output speed of the engine when an upshift of the transmission is being actuated. The system selectively actuates a speed retardation system to decrease the engine output speed to match a desired engine output speed at the next highest gear ratio. In one embodiment, an engine control actuates engine braking to achieve this rapid speed reduction. In other embodiments, an additional load may be placed on the engine, such as the actuation of a fan. An operator is preferably provided with a shift intent switch that provides an indication to the engine control that an upshift will be actuated. The engine control waits for an indication that the transmission has been moved to neutral. Once this indication is received, the speed retardation system is actuated to rapidly reduce the engine output speed toward a desired value. Most preferably, this feature is incorporated into an engine control system adapted to synchronize the engine output speed to that desired at the next gear ratio, both when the transmission is being upshifted or downshifted. The engine control system allows an operator to achieve a transmission shift without complicated clutching of the transmission.

Engine speed retardation on transmission upshift

An engine control provides rapid decrease in the output speed of the engine when an upshift of the transmission is being actuated. The system selectively actuates a speed retardation system to decrease the engine output speed to match a desired engine output speed at the next highest gear ratio. In one embodiment, an engine control actuates engine braking to achieve this rapid speed reduction. In other embodiments, an additional load may be placed on the engine, such as the actuation of a fan. An operator is preferably provided with a shift intent switch that provides an indication to the engine control that an upshift will be actuated. The engine control waits for an indication that the transmission has been moved to neutral. Once this indication is received, the speed retardation system is actuated to rapidly reduce the engine output speed toward a desired value. Most preferably, this feature is incorporated into an engine control system adapted to synchronize the engine output speed to that desired at the next gear ratio, both when the transmission is being upshifted or downshifted. The engine control system allows an operator to achieve a transmission shift without complicated clutching of the transmission.

A vehicle drive incorporates a speed control that assists an operator in shifting the transmission without requiring the clutch, or synchronization of engine speed. An operator is provided with a single switch that allows a prediction of the next shift direction, and also a request for torque elimination to begin a gear shift. The electronic control unit modifies the engine fueling to a predicted value to achieve a zero torque load, thus allowing the operator to move the transmission to neutral. The transmission is provided with a neutral switch that provides a positive signal to the electronic control unit of when the transmission is in neutral and when it is engaged. Once the electronic control receives the neutral signal, it begins to modify the engine speed to achieve the desired synchronization speed. The operator is thus able to engage the new gear. Once the new gear is engaged, control over the engine returns to the operator.

Combined system for assisting shifting of manual transmission

An operator of a vehicle may request torque reduction on the connection between a transmission and an engine, or may use a clutch. A switch is provided to send a torque elimination request. Upon receiving the request, an engine control adjusts engine fueling to achieve a zero torque load on a transmission to allow an operator to shift the transmission to neutral without clutching. The engine control predicts the engine fueling to achieve a zero torque load, and begins adjusting fueling to approach that predicted value. The prediction of the zero torque value is based on system variables other than torque load. Since the actual zero torque fueling varies, it is difficult to measure or predict. Moreover, a torque meter for measuring actual torque is expensive and difficult to maintain. The present invention addresses this difficulty by adjusting the engine fueling above and below the predicted zero torque value. In this way, the actual engine fueling will repeatedly cross the actual zero torque value such that the operator will be able to move the transmission out of gear to a neutral position.

Method and apparatus for assisting in shifting transmission to neutral

An operator input control system for a system to assist shifting in a multi-speed transmission includes a switch that allows an operator to provide an indication of the direction of the next shift. The operator is also provided with a switch that allows a request for torque elimination to move the transmission to neutral without clutching. In one embodiment, the operator is able to provide the shift indication separately from requesting torque elimination. In a second embodiment, a single three position switch is utilized to provide both the request for torque elimination and the shift indication. The system is operable to initially eliminate or reduce the torque load between the engine and the transmission such that the operator is able to move the transmission to neutral without clutching. The system then begins to move the engine output speed to a speed that is synchronized with the value necessary at the next gear to achieve a relatively smooth speed shift.

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Northville, MI, United States of America

Edward M Bacon