Continuously variable transmission control
AssigneeHyster-Yale Group, Inc.
InventorsConor Bradley, Robert Kee
Life of this patent
Estimating the term…
Abstract
A control system for a vehicle uses one or more inputs of a velocity request, a brake request, a speed request, travel direction indication, engine speed, and vehicle speed to determine a control strategy for a continuously variable transmission. A target engine speed is selected based upon the inputs, and the engine and continuously variable transmission ratio are controlled to achieve the target engine speed while controlling the vehicle according to the inputs. In some embodiments, the control strategy further selects the target engine speed according to accessory system demands, such as a hoist or lift system.
Claims19
A method for controlling a vehicle equipped with an engine coupled to a continuously variable transmission (CVT) with a controllable drive ratio, comprising:
- via a processor on the vehicle, monitoring a current engine speed;
- via the processor on the vehicle, monitoring a transmission output speed;
- via the processor on the vehicle and based upon a commanded vehicle speed being greater than a current vehicle speed, executing an acceleration process comprising:
- determining an acceleration engine speed based on the commanded vehicle speed;
- determining a target engine speed that is greater than the acceleration engine speed;
- commanding the engine to operate at the target engine speed;
- iteratively determining, each time a predetermined amount of time elapses, whether the transmission output speed has changed compared to the transmission output speed at the end of the previous iteration, and, in response to the transmission output speed having changed, determining a new acceleration drive ratio for the CVT, wherein the new acceleration drive ratio facilitates the engine operating at the acceleration engine speed;
- and
- iteratively changing the CVT to the new acceleration drive ratio.
A non-transitory computer readable medium (CRM) comprising instructions that, when executed by a processor of a vehicle systems manager, cause the vehicle systems manager to:
- monitor a current engine speed;
- monitor a transmission output speed;
- based upon a commanded vehicle speed being greater than a current vehicle speed, execute an acceleration program causing the processor of the vehicle system manager to:
- determine an acceleration engine speed based on the commanded vehicle speed;
- determine a target engine speed that is greater than the acceleration engine speed;
- command the engine to operate at the target engine speed;
- iteratively determine, for each time a predetermined amount of time elapses, whether the transmission output speed has changed compared to the transmission output speed at the end of the previous iteration, and, in response to the transmission output speed having changed, determine a new acceleration drive ratio for the CVT, wherein the new acceleration drive ratio is decreased compared to the previous acceleration drive ratio to facilitate the engine operating at the acceleration engine speed if the current engine speed is less than the acceleration engine speed, or wherein the new acceleration drive ratio is increased compared to the previous acceleration drive ratio to facilitate the engine operating at the acceleration engine speed if the current engine speed is greater than the acceleration engine speed;
- and
- iteratively change the CVT to the new acceleration drive ratio.
A system for controlling a vehicle powered by an engine coupled to a continuously variable transmission (CVT), 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 receive a commanded vehicle speed;
- wherein the processor is configured to either receive or determine a current 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 accelerate the vehicle, based upon the commanded vehicle speed being greater than the current vehicle speed, by:
- determining an acceleration engine speed and a target engine speed that is greater than the acceleration engine speed;
- causing the electronic engine speed control actuator to command the engine to operate at the target engine speed;
- determine a target drive ratio for the CVT based on the engine speed and the transmission output shaft speed to cause the engine to operate at the selected engine speed;
- causing the electronic transmission ratio control actuator to operate the CVT at the target drive ratio;
- and
- at a predetermined time interval, repeatedly redetermining the target drive ratio in response to the transmission output shaft speed changing, and causing the electronic transmission ratio control actuator to operate the CVT at the redetermined target drive ratio to cause the engine to operate at the selected engine speed.
Dependencies are inferred from the claim text.