Continuously variable transmission control

A non-transitory computer readable medium comprising instructions that, when executed by a processor of a vehicle systems manager, cause the vehicle systems manager to:

• receive a first signal from an operator of the lift truck to move the lift truck at a vehicle speed while not lifting a load using the lift mechanism;
• in response to the first signal, control the engine to operate at a first revolution rate and control the continuously variable transmission to operate at a first input-to-output ratio, so as to cause the lift truck to move at the vehicle speed while not lifting a load using the lift mechanism;
• receive a second signal from the operator to operate the lift mechanism to lift a load while the lift truck is moving at the vehicle speed;
• in response to the second signal, control the engine to operate at a second revolution rate and control the continuously variable transmission to operate at a second input-to-output ratio, wherein the second revolution rate is greater than the first revolution rate and the second input-to-output ratio is less than the first input-to-output ratio, so as to generate additional power from the engine while maintaining approximately the same vehicle speed;
• and
• use the additional power from the engine to power the lift mechanism while the lift truck moves at approximately the same vehicle speed.

A system for controlling an engine and a continuously variable transmission in a lift truck comprising one or more wheels powered by the engine via the continuously variable transmission and a lift mechanism powered by the engine for vertically lifting a load carried by the lift truck, the system comprising:

• a processor operatively coupled to an engine speed source, operatively coupled to a transmission output shaft speed source, operatively coupled to an electronic engine speed control actuator, and operatively coupled to an electronic transmission ratio control actuator;
• wherein the processor is configured to either receive or determine a vehicle speed;
• wherein the processor is configured to either receive an engine speed from the engine speed source or to determine the engine speed based on the engine speed source;
• wherein the processor is configured to either receive a transmission output shaft speed from the transmission output shaft speed source or to determine the transmission output shaft speed based on the transmission output shaft speed source;
• wherein the processor is programmed to generate additional power from the engine while maintaining approximately a constant vehicle speed by:
• receiving a first signal from an operator of the lift truck to move the lift truck at a vehicle speed while not lifting a load using the lift mechanism;
• in response to the first signal, causing the electronic engine speed control actuator to command the engine to operate at a first revolution rate and
• in response to the first signal, causing the electronic transmission ratio control actuator to operate the continuously variable transmission at a first input-to-output ratio, so as to cause the lift truck to move at the vehicle speed while not lifting a load using the lift mechanism;
• receiving a second signal from the operator to operate the lift mechanism to lift a load while the lift truck is moving at the vehicle speed;
• in response to the second signal, causing the electronic engine speed control actuator to command the engine to operate at a second revolution rate;
• in response to the second signal, causing the electronic transmission ratio control actuator to operate the continuously variable transmission at a second input-to-output ratio, wherein the second revolution rate is greater than the first revolution rate and the second input-to-output ratio is less than the first input-to-output ratio, so as to generate additional power from the engine while maintaining approximately the same vehicle speed;
• using the additional power from the engine to power the lift mechanism while the lift truck moves at approximately the same vehicle speed.