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EP-4735858-A1 - SYSTEM AND METHOD FOR EVALUATING CONTINUOUSLY VARIABLE TRANSMISSION

EP4735858A1EP 4735858 A1EP4735858 A1EP 4735858A1EP-4735858-A1

Abstract

A system and method of evaluating a continuously variable transmission (CVT) on a vehicle (22) includes positioning a vehicle (22) having a CVT (26) on a test stand (24), where the test stand (24) comprises rollers (58, 60) for receiving wheel assemblies (36, 38) of the vehicle (22), and with the vehicle (22) further including a drivetrain (40) and an electronic system (28) comprising a transmission controller (50a). The vehicle (22) is operated on the test stand (24) whereby wheel assemblies (36, 38) of the vehicle (22) are rotated via the drivetrain (40) of the vehicle (22). A computer (54) acquires data from the electronic system (28) of the vehicle (22) while the vehicle (22) is being operated on the test stand (24) with the data used to determine whether the CVT (26) is operating acceptably based on the acquired data.

Inventors

  • LAWRENCE, JON D.
  • POTTS, Landon W.

Assignees

  • BPG Sales and Technology Investments, LLC

Dates

Publication Date
20260506
Application Date
20240701

Claims (20)

  1. 1. A method of evaluating a continuously variable transmission (CVT) on a vehicle comprising: positioning a vehicle having a CVT on a test stand, wherein the test stand comprises rollers for receiving wheel assemblies of the vehicle, and wherein the vehicle further includes a drivetrain, and an electronic system comprising a transmission controller; operating the vehicle on the test stand whereby wheel assemblies of the vehicle are rotated via the drivetrain of the vehicle; acquiring with a computer data from the electronic system of the vehicle during said operating the vehicle on the test stand; and determining whether the CVT is operating acceptably based on the acquired data.
  2. 2. The method of claim 1 , wherein the acquired data comprises data from a transmission controller of the vehicle.
  3. 3. The method of claim 1, wherein the acquired data comprises a target pulley gear ratio of the CVT and an actual pulley gear ratio of the CVT.
  4. 4. The method of any of claims 1 to 3, wherein the acquired data comprises the rotational speed of either a primary pulley of the CVT and/or a secondary pulley of the CVT.
  5. 5. The method of any of claims 1 to 3, wherein said determining comprises analyzing the acquired data by comparing a target pulley gear ratio of the CVT relative to an actual pulley gear ratio of the CVT.
  6. 6. The method of claim 5, wherein said determining comprises comparing the acquired data to a predetermined acceptable criteria.
  7. 7. The method of any of claims 1 to 3, wherein said determining comprises evaluating the acquired data via an evaluation program residing on the computer.
  8. 8. The method of any of claims 1 to 3, wherein said operating the vehicle on the test stand comprises operating the vehicle by a person while the vehicle is on the test stand.
  9. 9. The method of claim 8, wherein said operating comprises accelerating the vehicle from a first speed to a second speed, and wherein the second speed is higher than the first speed.
  10. 10. The method of claim 9, wherein accelerating the vehicle to the second speed comprises accelerating the vehicle to a highway speed.
  11. 11. The method of any of claims 1 to 3, wherein said determining comprises analyzing a portion of the acquired data.
  12. 12. The method of any of claims 1 to 3, wherein said determining whether the CVT is operating acceptably comprises determining whether the CVT is slipping, and wherein said determining whether the CVT is slipping comprises determining whether a pulley of the CVT is slipping relative to a belt of the CVT.
  13. 13. The method of claim 12, wherein said determining whether the CVT is slipping comprises determining whether the primary pulley of the CVT is slipping relative to the belt and/or the secondary pulley is slipping relative to the belt.
  14. 14. A method of evaluating a continuously variable transmission (CVT) on a vehicle comprising: positioning a vehicle having a CVT on a test stand, wherein the test stand comprises rollers for receiving wheel assemblies of the vehicle, and wherein the vehicle further includes a drivetrain, and an electronic system comprising a transmission controller; operating the vehicle on the test stand whereby wheel assemblies of the vehicle are rotated via the drivetrain of the vehicle; acquiring with a computer data from the electronic system of the vehicle during said operating the vehicle on the test stand, wherein the acquired data comprises a target pulley gear ratio of the CVT and an actual pulley gear ratio of the CVT ; and determining whether the CVT is operating acceptably based on the acquired data, and wherein said determining comprises analyzing the acquired data by comparing the target pulley gear ratio of the CVT relative to the actual pulley gear ratio of the CVT.
  15. 15. The method of claim 14, wherein the acquired data comprises data from a transmission controller of the vehicle.
  16. 16. The method of claim 14, wherein the acquired data further comprises the rotational speed of either a primary pulley of the CVT and/or a secondary pulley of the CVT.
  17. 17. The method of any of claims 14 to 16, wherein said analyzing the acquired data comprises comparing the acquired data to a predetermined acceptable criteria.
  18. 18. A system for evaluating a continuously variable transmission (CVT) on a vehicle comprising: a test stand having rollers for receiving wheel assemblies of a vehicle equipped with a CVT, wherein the test stand is configured to enable a drivetrain of the vehicle to drive wheels of the vehicle while disposed on the test stand; a computer configured to be operably connected to an electronic system of the vehicle, where the electronic system comprises a transmission controller; wherein the computer is configured to receive data from the electronic system during operation of the vehicle on the test stand, and wherein the system is further configured to determine whether the CVT is operating acceptably based on the acquired data.
  19. 19. The system of claim 18, wherein the acquired data comprises a target pulley gear ratio of the CVT and an actual pulley gear ratio of the CVT, and wherein the system is configured to determine whether the CVT is operating acceptably by comparing the target pulley gear ratio of the CVT relative to the actual pulley gear ratio of the CVT.
  20. 20. The system of either of claims 18 or 19, wherein the acquired data comprises the rotational speed of either a primary pulley of the CVT and/or a secondary pulley of the CVT.

Description

SYSTEM AND METHOD FOR EVALUATING CONTINUOUSLY VARIABLE TRANSMISSION CROSS REFERENCE TO RELATED APPLICATION [0001] The present application claims priority of U.S. provisional application Ser. No. 63/524,487 filed June 30, 2024, which is hereby incorporated herein by reference in its entirety BACKGROUND AND FIELD OF THE INVENTION [0002] The present invention is directed to a system and method for evaluating continuously variable transmissions, in particular evaluating a continuously variable transmission of a vehicle on a test stand. [0003] Continuously variable transmissions (CVTs) are known and are a form of automatic transmission for a vehicle, such as a passenger vehicle, where the CVT can change through a continuous range of gear ratios as opposed to a conventional automatic transmission that has a number of gears that each set a particular gear ratio. CVTs enable a vehicle engine to operate at or within a particular range of optimal RPMs (revolutions per minute) with the vehicle moving at different velocities. For example, this may include operating the engine at or within a particular range of optimal RPMs at which the engine is generating a desirable power or torque level, or fuel consumption level. SUMMARY OF THE INVENTION [0004] The present invention provides a system and method for rapidly evaluating the operational performance of a CVT in a vehicle, and is particularly useful for evaluating such a transmission in a used vehicle. [0005] According to an aspect of the present invention, a method of evaluating a continuously variable transmission (CVT) on a vehicle comprises positioning a vehicle having a CVT on a test stand, where the test stand comprises rollers for receiving wheel assemblies of the vehicle, and the vehicle includes a drivetrain, and an electronic system comprising a transmission controller. The method further includes operating the vehicle on the test stand such that wheel assemblies of the vehicle are rotated via the drivetrain of the vehicle, acquiring data with a computer from the electronic system of the vehicle during the step of operating the vehicle on the test stand, and determining whether the CVT is operating acceptably based on the acquired data. [0006] In particular aspects of the method, the acquired data comprises data from the transmission controller, such as a target pulley gear ratio of the CVT and an actual pulley gear ratio of the CVT. The acquired data may additionally or alternatively comprise the rotational speed of a pulley of the CVT, such as either a primary pulley of the CVT and/or a secondary pulley of the CVT, such as a target speed and/or an actual speed of a pulley of the CVT, such as either a primary pulley of the CVT and/or a secondary pulley of the CVT. The step of determining whether the CVT is operating acceptably can involve analyzing the acquired data, such as for example, comparing a target pulley gear ratio of the CVT relative to an actual pulley gear ratio of the CVT and/or comparing a target speed of one or both of the primary or the secondary pulleys of the CVT to an actual speed of the respective pulley or pulleys, and/or may comprise comparing the acquired data to a predetermined acceptable criteria. [0007] In accordance with a still further aspect, the step of determining whether the CVT is operating acceptably may comprise evaluating the acquired data via an evaluation program, such as an evaluation program residing on the computer. This includes comparing the acquired data to a predetermined acceptable criteria using the evaluation program. [0008] The step of operating the vehicle on the test stand may comprise operating the vehicle by a person while the vehicle is on the test stand, and/or may further or additionally comprise accelerating the vehicle. The step of accelerating the vehicle may involve accelerating the vehicle from a first speed to a second speed, for example, where the second speed is higher than the first speed, such as from zero or a slow speed to a highway speed, such as in the range of 55 mph to 80 mph, or in the range of 60 mph to 80 mph. The step of accelerating the vehicle may be performed at a rate whereby the CVT does not simulate a conventional multi-speed automatic transmission. That is, the acceleration is performed at a rate whereby the CVT does not simulate gear changes. The step of determining whether the CVT is operating acceptably may include analyzing at least a portion of the acquired data. [0009] Still further, determining whether the CVT is operating acceptably may comprise determining whether the CVT is slipping, including such as determining whether a pulley of the CVT is slipping relative to a belt of the CVT. The step of determining whether the CVT is slipping may further comprise determining whether the primary pulley of the CVT is slipping relative to the belt and/or the secondary pulley is slipping relative to the belt. [0010] According to another aspect of the present invention, a system