Meritor Heavy Vehicle Systems Limited

Rockwell International Corporation

Zf Meritor, LLC

Detroit Diesel Corporation

Other

Rockwell Heavy Vehicle Systems, Inc.

Jon M Huber

Charles E Allen, Jr

Thomas P Desautels

Steven E Radue

Frank A Palmeri

Edward M Bacon

Steve M Weisman

Bryant K McLaughlin

Fabian J Dechant

Christopher S Keeney

Robert Anthony Sayman

James Henry Devore

Andreas B&ouml;hm

Gerhard Bockmann

Gerhard B&ouml;ckmann

Andreas Bohm

Sean Carey

James De Vore

A semi-automated vehicle transmission includes a method of returning torque control to the driver of the vehicle. The transition from an initial current torque value to a desired torque value is accomplished in two stages. A first rate of change is utilized during a preselected time period or until the current torque value corresponds to the desired torque value. In the event that the desired torque value is not achieved during the preselected period of time, then a second rate of change is implemented. The second rate of change preferably is very aggressive relative to the first rate of change. The rate of change of the current torque value is accomplished within a window of available torque limits that progressively change with time.

Two stage torque control method for a vehicle transmission

A shift by wire vehicle transmission system includes control methods that are especially useful for controlling the transmission under start-from-stop conditions. Since the master clutch must be manually operated under such conditions, the invention includes a method of determining whether the clutch is open or closed. The rotational speed of the engine output shaft is compared to the rotational speed of the transmission input shaft and if the difference between those speeds is greater than a preselected value, the clutch is determined to be open. Another use of the disclosed method is to provide an indication to the driver whether a desired gear has been engaged. A visual or audible signal indicates to the driver that the desired gear is not yet engaged. Once engagement is confirmed, the signal is turned off and the driver knows that the desired shift has been accomplished.

Method and system for determining clutch status in a vehicle

A shift by wire vehicle transmission includes control methods for engaging gears after the vehicle has been at rest or coasting. When the vehicle is started from a stop or rest, a default starting gear is automatically selected. The driver can override the default gear and choose to start driving the vehicle in one gear above or below the default starting gear by manipulating a shift lever. Similarly, the driver can override the default starting gear to begin driving the vehicle in reverse. When the vehicle has been coasting, the transmission control unit chooses the next gear based upon a signal that is provided when the driver manipulates the shift lever. Depending on the indicated desire of the driver, the system controller automatically selects a gear depending upon vehicle speed and torque conditions.

Control methods for a shift by a wire vehicle transmission

A method of engaging and disengaging transmission gears in a vehicle is provided. A controller processes an initial torque representing an engine torque and an estimated zero torque representing an estimate of a transmission output shaft torque. The controller also sets a high and low band torque about the estimated zero torque. Once the above torques have been determined, the controller compares the initial torque to the high band torque. If the initial torque is below the high band torque, the controller increases the engine torque to the high band torque. If the initial torque is greater than the high band torque, then no preliminary adjustments to the engine torque need be made. At least one shift valve is energized when the engine torque is equal to or greater than the high band torque. The engine torque is decayed by the controller to the low band torque to facilitate engaging and disengaging transmission gears.

Shift synchronization using decaying torque

A vehicle transmission assembly includes a main gear box and an auxiliary or range gear box. An electrical actuation device for effecting changes in the range gear box preferably includes a solenoid actuator associated with each of the range gear members. A switch, which is preferably provided on the shift lever handle, allows the driver of the vehicle to indicate a desire to make a change in the range gear box. The solenoid actuators are responsive to the electrical switch to effect the range shift. The electrical components replace pneumatic components and associated fittings and airlines used with some prior systems. A further feature of this invention is to include a synchronizer protection circuit that disables the solenoid actuators unless prescribed transmission conditions are met.

Electrical transmission range shift system

Control methods for a shift by wire vehicle transmission

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

A system for automatically effecting a range shift between high and low ranges in a multi-speed transmission includes a control that monitors the output speed of both the engine and the transmission. The ratio of the two speeds is compared to available ratios in a look-up table such that the control is constantly determining the engaged gear. In one embodiment, a driver provides an intention of the next gear to be selected to the control. Should the intended gear shift require a range shift from the engaged gear, the control actuates the range shift once the transmission has been moved to neutral. In a second embodiment, no driver intention is provided to the controller. Instead, the control compares the engine output speed to threshold values. If the threshold values predict a gear shift that would require a range shift to be effected from the currently engaged gear, then the range shift will be effected once the transmission has been moved to neutral.

Automatic range shift for multi-speed 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 operator input control system assists shifting between gears in a multi-speed transmission without clutching. A single switch allows an operator to provide an indication of the next gear that is to be selected, and further allows the operator the option of requesting torque elimination when moving the transmission to neutral. In one embodiment, the switch includes a rotatable switch body that is held in either an upshift or downshift intent position. The operator is able to move the switch a slight additional rotational amount beyond the intent position to request torque elimination. Once the operator releases the switch, it returns to the upshift or downshift indicated position. The inventive switch reduces the complexity of operator input in an overall system for assisting an operator in shifting transmission speeds without clutching.

Four position switch for shift assist system

A shift by wire transmission system enables a driver to manually select a next desired gear and the system completes the shift automatically without requiring the driver to operate the clutch. The system includes an electronic transmission control unit that communicates with an electronic engine control unit to control engine speed during a shift in order to synchronize the speed of an engine shaft and the transmission shaft. The driver manually chooses a gear shift by moving a shift lever to thereby produce electrical signals indicative of the desired change in gears. Multiple or skip shifting is possible along with a method of automatically choosing a default gear in the event that the vehicle transmission is placed in neutral while the vehicle is in motion.

Shift by wire transmission system

A system for automatically effecting a range shift between high and low ranges in a multi-speed transmission includes a control that monitors the output speed of both the engine and the transmission. The ratio of the two speeds is compared to available ratios in a look-up table such that the control is constantly determining the engaged gear. In one embodiment, a driver provides an intention of the next gear to be selected to the control. Should the intended gear shift require a range shift from thee engaged gear, the control actuates the range shift once the transmission has been moved to neutral. In a second embodiment, no driver intention is provided to the controller. Instead, the control compares the engine output speed to threshold values. If the threshold values predict a gear shift that would require a range shift to be effected from the currently engaged gear, then the range shift will be effected once the transmission has been moved to neutral.

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.

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Laurinburg, NC, United States of America

Jon M Huber