Caterpillar Inc.

Lorne W Tweed

Charles W Birchenough

William M McClure

William James Tate

Noel J Rytter

Hans P Dietz

Rolland D Scholl

Kenneth P Liesener

Kevin Dwight King

Dwight S Holloway

Brian T Rolli

Timothy A Cross

Michael B Brennemann

The present invention provides a sensing system and method for providing information relating to a drivetrain during shifting operations. The drivetrain includes an engine, a torque converter and a transmission. The system includes sensors for detecting the output speed of the engine, the output speed of the torque converter, and the output speed of the transmission. The system detects the starting condition of a shifting operation, responsively determines a set of performance parameters, and produces a set of performance parameter signals.

Method and system for diagnosing a drivetrain during shifting operations

A control system is provided for a vehicle regulating engine speed during shifts so as to reduce driveline torque and shift shock. The control system includes separate microprocessor based engine and transmission controllers which communicate via a data link. When a shift is initiated, the transmission controller delays a first period of time CTSDELAY sufficient for the transmission to disengage the old gear ratio and then produces a CTSSPEED signal. The transmission controller continues to produce the CTSSPEED signal for a second period of time CTSDUR which corresponds to the time required for the transmission to engage the new gear ratio. The engine controller receives the desired engine speed signal and regulates engine speed into correspondence with the desired speed. During upshifts, the CTSSPEED signal is set to a speed which is a predetermined amount above the synchronization speed of the new gear for an upshift. Conversely, during downshifts, the CTSSPEED is set to a speed which is a predetermined amount below the synchronization speed in the new gear. The control system preferably includes a unit [means] for sensing a lockup time period corresponding to the time required for the transmission to lock up in the new gear ratio. The control system is capable of modifying the second time period CTSDUR as a function of the sensed lockup time period.

Integrated engine and transmission control system

The present invention provides a control which automatically elevates engine speed to a preselected value when the vehicle coasting in neutral above a preselected speed. In order to accomplish this objective, the engine controller is adapted to receive an actual gear ratio signal and a vehicle speed signal, If the vehicle is in neutral and engine speed is above a preselected threshold, the controller sets the desired engine speed to a preselected value which has been empirically determined to ensure sufficient transmission cooling and lubrication, Controlling to this speed also reduces transmission wear when the transmission is reengaged at high ground speeds.

Elevated low idle for coasting in neutral

A control system is provided for a vehicle regulating engine speed during shifts so as to reduce driveline torque and shift shock. The control system includes separate microprocessor based engine and transmission controllers which communicate via a data link. When a shift is initiated, the transmission controller delays a period of time sufficient for the transmission to disengage the old gear ratio and then produces a CTSSPEED signal. The transmission controller continues to produce the CTSSPEED signal for a second period of time which corresponds to the time required for the transmission to engage the new gear ratio. The engine controller receives the desired engine speed signal and regulates engine speed into correspondence with the desired speed. During upshifts, the CTSSPEED signal is set to a speed which is a predetermined amount above the synchronization speed of the new gear for an upshift. Conversely, during downshifts, the CTSSPEED is set to a speed which is a predetermined amount below the synchronization speed in the new gear.

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Peoria, IL, United States of America

Lorne W Tweed