Continuous Variable Transmission System

• US 20080306664A1
• Filed: 06/11/2007
• Published: 12/11/2008
• Est. Priority Date: 06/11/2007
• Status: Active Grant

• Current Assignee: Cummins Incorporated
• Original Assignee: Cummins Incorporated
• Inventors: Guo, Linsong, Frazier, Tim R.
• Granted Patent: US 8,606,474 B2
• Time in Patent Office: Days
• US Class Current: 701/54
• CPC Class Codes: B60W 10/04 including control of propulsion units
• CPC Class Codes: B60W 10/101 Infinitely variable gearings
• CPC Class Codes: B60W 30/1819 Propulsion control with control means using analogue circuits, relays or mechanical links
• CPC Class Codes: F16H 61/66 specially adapted for continuously variable gearings control of exclusively fluid gearing F16H61/38
• CPC Class Codes: Y02T 10/40 Engine management systems
• CPC Class Codes: Y02T 10/84 Data processing systems or methods, management, administration

Abstract

A method and system for controlling a continuously variable transmission (CVT). In one embodiment, the method includes receiving vehicle operation data. The method also includes controlling engine and transmission operations based on the vehicle operation data, fuel efficiency data, and CVT efficiency data.

Claims

1. A method for controlling a continuously variable transmission (CVT), the method comprising:

receiving vehicle operation data; and

controlling engine and transmission operations based on the vehicle operation data, fuel efficiency data, and CVT efficiency data.

2. The method of claim 1 wherein the vehicle operation data comprises a vehicle speed and a required engine power.

3. The method of claim 1 wherein the fuel efficiency data is based on a relationship between engine speed and engine torque that achieves optimal fuel efficiency.

4. The method of claim 1 wherein the CVT efficiency data is based on a relationship between engine speed and engine torque that achieves an optimal CVT ratio.

5. The method of claim 1 further comprising:

determining an optimal engine speed based on the vehicle operation data and the fuel efficiency data;

determining a fixed-speed mode speed based on fuel efficiency data;

if the optimal engine speed is substantially equal to or greater than the fixed-speed mode speed, controlling the transmission operations in a fixed-speed mode such that engine torque is a function of vehicle operation conditions; and

if the optimal engine speed is less than the fixed-speed mode speed, controlling the transmission operations in an optimal-operation mode such that engine torque is a function of a varying engine speed.

6. The method of claim 1 further comprising:

determining an optimal engine speed based on the vehicle operation data and the fuel efficiency data;

determining an overall CVT ratio that is based on the optimal engine speed and a vehicle speed; and

selecting the highest possible gear number based on the overall CVT ratio, AMT gear ratio, and front box ratio.

7. The method of claim 1 further comprising modifying the fuel efficiency data and the CVT efficiency data based on emissions data.

8. A computer-readable medium containing program instructions for controlling a continuously variable transmission (CVT), the program instructions which when executed by a computer system cause the computer system to execute a method comprising:

receiving vehicle operation data; and

controlling engine and transmission operations based on the vehicle operation data, fuel efficiency data, and CVT efficiency data.

9. The computer-readable medium of claim 8 wherein the vehicle operation data comprise a vehicle speed and a required engine power.

10. The computer-readable medium of claim 8 wherein the fuel efficiency data is based on a relationship between engine speed and engine torque that achieves optimal fuel efficiency.

11. The computer-readable medium of claim 8 wherein the CVT efficiency data is based on a relationship between engine speed and engine torque that achieves an optimal CVT ratio.

12. The computer-readable medium of claim 8 further comprising program instructions for:

determining an optimal engine speed based on the vehicle operation data and the fuel efficiency data;

determining a fixed-speed mode speed based on fuel efficiency data;

if the optimal engine speed is substantially equal to or greater than the fixed-speed mode speed, controlling the transmission operations in a fixed-speed mode such that engine torque is a function of vehicle operation conditions; and

if the optimal engine speed is less than the fixed-speed mode speed, controlling the transmission operations in an optimal-operation mode such that engine torque is a function of a varying engine speed.

13. The computer-readable medium of claim 8 further comprising program instructions for:

determining an optimal engine speed based on the vehicle operation data and the fuel efficiency data;

determining an overall CVT ratio that is based on the optimal engine speed and a vehicle speed; and

selecting the highest possible gear number based on the overall CVT ratio, ATM gear ratio, and front box ratio.

14. The computer-readable medium of claim 8 further comprising program instructions for modifying the fuel efficiency data and the CVT efficiency data based on emissions data.

15. A continuously variable transmission (CVT) system comprising:

a CVT controller operative to receive vehicle operation data;

an electronic control module (ECM) operatively coupled to the CVT controller and operative to receive the vehicle operation data;

a CVT front box operatively coupled to the CVT controller and the ECM; and

an automated manual transmission (AMT) operatively coupled to the CVT controller and the ECM, wherein the CVT controller and the ECM are operative to control transmission operations of the CVT front box and the AMT based on the vehicle operation data, fuel efficiency data, and CVT efficiency data.

16. The system of claim 15 wherein the vehicle operation data comprise a vehicle speed and a required engine power.

17. The system of claim 15 wherein the fuel efficiency data is based on a relationship between engine speed and engine torque that achieves optimal fuel efficiency.

18. The system of claim 15 wherein the CVT efficiency data is based on a relationship between engine speed and engine torque that achieves an optimal CVT ratio.

19. The system of claim 15 wherein the ECM is operable to:

determine an optimal engine speed based on the vehicle operation data and the fuel efficiency data;

determine a fixed-speed mode speed based on fuel efficiency data;

if the optimal engine speed is substantially equal to or greater than the fixed-speed mode speed, control the transmission operations in a fixed-speed mode such that engine torque is a function of vehicle operation conditions; and

if the optimal engine speed is less than the fixed-speed mode speed, control the transmission operations in an optimal-operation mode such that engine torque is a function of a varying engine speed.

20. The system of claim 15 wherein the CVT controller is operable to:

determine an optimal engine speed based on the vehicle operation data and the fuel efficiency data;

determine an overall CVT ratio that is based on the optimal engine speed and a vehicle speed; and

select the highest possible gear number based on the overall CVT ratio, ATM gear ratio, and front box ratio.

21. A vehicle comprising:

an engine; and

a continuously variable transmission (CVT) system coupled to the engine, the CVT system comprising;

a CVT controller operative to receive vehicle operation data;

an electronic control module (ECM) operatively coupled to the CVT controller and operative to receive the vehicle operation data;

a CVT front box operatively coupled to the CVT controller and the ECM; and

an automated manual transmission (AMT) operatively coupled to the CVT controller and the ECM, wherein the CVT controller and the ECM are operative to control transmission operations of the CVT front box and the AMT based on the vehicle operation data, fuel efficiency data, and CVT efficiency data.