Rockwell International Corporation

Detroit Diesel Corporation

Meritor Heavy Vehicle Systems Limited

Steve M Weisman

Thomas P Desautels

Edward M Bacon

Jon M Huber

Jeffery Scott Hawkins

Charles E Allen, Jr

Steven E Radue

Frank A Palmeri

Charles Chapin Blake

Ronald William Mikulik

Various control strategies and techniques for controlling a variable speed fan in an internal combustion engine are provided. The various control techniques improve fuel economy by operating the fan at a speed sufficient to cool the engine, while avoiding unnecessarily higher speeds that result in poor fuel economy. Further, the fan may be completely disabled at cold start up to avoid over cooling, particularly in an engine using a charge air cooling system.

Method of controlling a variable speed fan

A method of controlling an internal combustion engine having a variable speed fan driven by a torque multiplying fan driver includes controlling the variable speed fan with closed loop control based on fan speed.

Closed loop fan control using fan speed feedback

A method of controlling an internal combustion engine having a variable speed fan includes controlling the variable speed fan with closed loop control based on fan motor hydraulic pressure. A reference fan pressure is based on an applied fan request signal. The actual fan motor pressure is monitored, and an error signal is determined by comparing the reference fan pressure to the actual fan pressure. The fan is driven based on the error signal.

Closed loop fan control using fan motor pressure feedback

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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Farmington Hills, MI, United States of America

Steve M Weisman