Control system for an automatic transmission having shift points based on part throttle positions which are used when engine speed is lowered below an adjustable minimum engine speed setting
AssigneeCaterpillar Inc.
InventorsJavad Hosseini, Randall M. Mitchell, Douglas A. Carlson, David L. Dickrell
Life of this patent
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Abstract
A control system and method is provided for changing the shiftpoints of a transmission for part throttle shifting. A input section delivers a actual gear signal, a engine speed signal and a torque converter output speed signal A controller receives the input signals and varies the transmission shiftpoints relative to the received signals. The controller also delivers signals to the transmission to upshift, downshift or that no shift is necessary.
Claims16
A control system adapted to be used on a machine having an engine and a transmission with a torque converter disposed therebetween, the transmission having predefined shiftpoints at a normal operating speed of the engine, the control system, comprising:
- a first input signal operative to sense the actual transmission gear;
- a second input signal operative to sense the speed of the engine;
- a third input signal operative to sense the output of the torque converter;
- a fourth input signal operative to sense a minimum engine speed setting;
- and
- a controller receiving the input signals and adjusting the shiftpoints within the transmission in response to lowering the speed of the engine to a predetermined minimum engine speed, said predetermined minimum engine speed being the minimum engine speed setting sensed by said fourth input signal.
A method of operating a control system associated with a machine having an engine and a transmission having a torque converter, the control system includes a controller for controlling shifting of the transmission, the method comprising the steps of:
- sensing an actual gear signal;
- sensing an engine speed signal;
- sensing a torque converter output speed signal;
- sensing a minimum engine speed setting signal;
- comparing the sensed signals and determining whether the transmission is to be upshifted, downshifted or unchanged;
- and
- sending a signal to the transmission to perform the determined action.
A control system adapted to be used on a machine having an engine and a transmission with a torque converter disposed therebetween, the transmission having predefined shiftpoints at a normal operating speed of the engine, the control system comprising:
- an actual gear input signal;
- a second input signal operative to sense the engine speed;
- a third input signal operative to sense the torque converter output speed;
- a fourth input signal adjustable for changing an minimum engine speed setting for changing the transmission shiftpoints;
- and
- a controller for receiving the input signals and adjusting the shiftpoints within the transmission in response to lowering the speed of the engine to a predetermined minimum engine speed corresponding to said minimum engine speed setting.
A controls system adapted to be used on a machine having an engine and a transmission with a torque converter disposed therebetween, the transmission having predefined shiftpoints at a normal operating speed of the engine, the control system, comprising:
- a first input signal operative to sense the actual transmission gear;
- a second input signal operative to sense the speed of the engine;
- a third input signal operative to sense the output speed of the torque converter;
- a fourth input signal operative to sense a minimum engine speed setting, the fourth input signal being adjustable by an operator for controlling the shiftpoints of the transmission;
- and
- a controller receiving the input signals and adjusting the shiftpoints within the transmission in response to lowering the speed of the engine to a predetermined minimum engine speed, said predetermined minimum engine speed being the minimum engine speed setting sensed by said fourth input signal.
Dependencies are inferred from the claim text.