Caterpillar Inc.

Bradley John Will

Randall Todd Anderson

Timothy A Lorentz

Matthew Michael Tinker

Mathew D Guldan

Chintan Govindbhai Kothari

Corwin Eugene Storer

Douglas James Carlton

Sudarshan Maiyur

Eric John Schultz

Paul D Cashatt

Chintankumar G Kothari

Lucas Micah Newlon

Timothy Alan Lorentz

A control system for monitoring a torque converter in a machine is disclosed. The control system includes a first speed sensor associated with a driving shaft of the torque converter. The first sensor is configured to measure an input speed of the torque converter. The control system further includes a second speed sensor associated with an output shaft of the torque converter. The second sensor is configured to measure an output speed of the torque converter. The control system further includes a processing module adapted to calculate a speed ratio based on the signals received from the first speed sensor and the second speed sensor. The control system further includes an output module adapted to provide indication for a seized condition of a one way clutch in the torque converter based on the speed ratio.

One way clutch operation monitoring in torque converter

A transmission system is disclosed for use with a machine. The transmission system may have a first clutch configured to transfer power in a first direction, a second clutch configured to transfer power in a second direction, a brake, and an interface device configured to generate a first signal indicative of a desire to shift power transfer directions. The transmission system may also have a controller configured to cause disengagement of the first clutch in response to the first signal, to cause the brake to apply a retarding torque to a traction device, and to determine an amount of the retarding torque being applied to the traction device. The controller may also be configured to selectively transfer the retarding torque to the second clutch when a capacity of the second clutch to provide retarding torque is about equal to the amount of the retarding torque being applied by the brake.

Transmission system implementing automated directional shift braking

A transmission system is disclosed for use with a machine. The transmission system may have a first clutch to transfer power in a first direction, a second clutch to transfer power in a second direction, a brake, a sensor to generate a first signal indicative of speed, and an input device to generate a second signal indicative of a desire to shift directions. The transmission system may also have a controller to cause disengagement of the first directional clutch in response to the second signal, and to cause the brake to apply retarding torque. The controller may also be configured to determine an error value based on the second signal and a target transmission system speed, to selectively increase retarding torque when the error value increases, and to selectively transfer retarding torque to the second directional clutch when a value of the second signal is less than a threshold value.

A brake system and method includes a test mode for determining a capacity of the brake system provided on a machine having a hydrostatic drive. A hydrostatic drive target differential pressure range is determined to simulate a test torque. A machine ground speed limit, hydrostatic drive actual differential pressure, and actual ground speed of the machine are determined. An output pressure of the hydrostatic pump is modulated to drive the hydrostatic drive actual differential pressure toward the hydrostatic drive target differential pressure range. A first test fault condition is determined when the actual ground speed exceeds the machine ground speed limit. A second test fault condition is determined when the hydrostatic drive actual differential pressure is outside the hydrostatic drive target differential pressure range.

Brake system having a brake capacity test mode for a machine having a hydrostatic drivetrain

A method for controlling a gear ratio rate of change in a machine having a continuously variable transmission includes moving an operator input device to a changed position, receiving electronic data indicative of the changed position, and determining a non-limited desired gear ratio based on the changed position. A maximum gear ratio rate of change corresponding to the non-limited desired gear ratio and an actual gear ratio of the continuously variable transmission is selected from an electronically stored gear ratio rate map. A current desired gear ratio is determined based on a previous desired gear ratio and the maximum gear ratio rate of change. A commanded gear ratio of the continuously variable transmission is changed to the current desired gear ratio using electronic signals.

Method of controlling gear ratio rate of change in continuously variable transmission

A method is provided for controlling a gear ratio change in a hydrostatic drive machine. The hydrostatic drive machine includes a variable displacement pump and at least one variable displacement motor fluidly connected with the variable displacement pump. The method includes a step of determining a gear ratio rate of change corresponding to a change from a current gear ratio to a new gear ratio. Start and stop overlap gear ratios corresponding to the gear ratio rate are determined and define an overlap range. The current gear ratio is changed to the new gear ratio using electronic signals at least in part by simultaneously changing displacements of the variable displacement pump and the at least one variable displacement motor at gear ratios within the overlap range, and sequentially changing displacements of the variable displacement pump and the at least one variable displacement motor at gear ratios outside the overlap range.

Method of effecting simultaneous displacement changes in hydrostatic drive machine

A system for controlling a transmission including a fluid pump and a fluid motor operably coupled to one another in a fluid circuit is disclosed. The system includes a controller configured to receive signals indicative of operator inputs, and determine a variable pressure limit in the fluid circuit based on the signals indicative of operator inputs. The controller is further configured to control displacement of at least one of the fluid pump and the fluid motor based on the variable pressure limit, such that a pressure level in the fluid circuit is maintained below the variable pressure limit.

System and method for controlling transmission based on variable pressure limit

A method is provided for controlling a gear ratio rate of change in a machine having a continuously variable transmission. The method includes moving an operator input device to a changed position, receiving electronic data indicative of the changed position, and determining a non-limited desired gear ratio based at least in part on the changed position. A maximum gear ratio rate of change corresponding to the changed position is selected from an electronically stored gear ratio rate map. A current desired gear ratio is determined based at least in part on the non-limited desired gear ratio and the maximum gear ratio rate of change. The method also includes changing a commanded gear ratio of the continuously variable transmission to the current desired gear ratio using electronic signals.

A method for indirectly detecting a movement of a machine and a failure of a speed sensor is disclosed. The method may include receiving an operator input signal, and determining a first factor based on the operator input signal. The method may also include measuring a machine operation parameter, and determining a second factor based on the machine operation parameter. The method may further include identifying a movement of the machine if the first factor is out of a first threshold range and the second factor is out of a second threshold range for at least a first threshold length of time. The method may also include determining a speed sensor failure if the movement of the machine is identified and no speed is detected by the speed sensor for at least a second threshold length of time.

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Peoria, IL, United States of America

Bradley John Will