MANUAL DOWNSHIFT CONTROL METHOD FOR AUTOMATIC TRANSMISSION

• US 20100016120A1
• Filed: 07/21/2008
• Published: 01/21/2010
• Est. Priority Date: 07/21/2008
• Status: Active Grant

• Current Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Original Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Inventors: Dorn, Aaron, Dickinson, Mike
• Granted Patent: US 8,771,144 B2
• Time in Patent Office: Days
• US Class Current: 477/107
• CPC Class Codes: F16H 2061/0496 for low engine torque, e.g. during coasting, sailing or engine braking
• CPC Class Codes: F16H 61/061 using electric control means
• CPC Class Codes: F16H 63/502 for smoothing gear shifts

Abstract

A control system and a method for controlling an automatic transmission that determines the disengagement of an off-going clutch and the engagement of an on-coming clutch by monitoring the corresponding hydraulic clutch pressures, and/or the calculated gear ratios with or without the assistance of off-pressure timer controls, or both.

Claims

1. A method comprising the steps of:

(a) providing a vehicle having an engine and an automatic transmission;

(b) determining a first hydraulic fluid pressure during an off-coming clutch phase;

(c) increasing the engine power when the first hydraulic fluid pressure reaches a first predetermined level;

(d) determining a second hydraulic fluid pressure; and

,

(e) reducing the engine power substantially fully when the second hydraulic fluid pressure reaches a second predetermined level.

2. The method of claim 1, wherein step (a) further comprises the step of:

transmitting a first input to a control unit, wherein the first input indicates the initiation of a manual downshift.

3. The method of claim 1, wherein step (a) further comprises the step of:

transmitting at least a first input to a control unit, wherein the first input indicates the initiation of a manual downshift at a low accelerator pedal opening.

4. The method of claim 1, wherein step (b) further comprises the step of:

determining that a first hydraulic line pressure switch has changed from an on state to an off state.

5. The method of claim 1, wherein step (d) further comprises the step of:

determining that a second hydraulic line pressure switch has changed from an off state to an on state.

6. The method of claim 1, wherein step (b) further comprises the steps of:

initiating a first delay; and

,

determining the expiration of the first delay.

7. The method of claim 1, wherein step (d) further comprises the step of:

determining an effective gear ratio, wherein the effective gear ratio is substantially equal to or greater than a predetermined value.

8. The method of claim 1, wherein step (d) further comprises the step of:

determining an effective gear ratio, wherein the effective gear ratio is substantially equal to or less than a predetermined value.

9. The method of claim 1, wherein step (d) further comprises the step of:

determining an effective gear ratio, wherein the effective gear ratio is greater than a predetermined value.

10. The method of claim 1, wherein step (d) further comprises the step of:

determining an effective gear ratio, wherein the effective gear ratio is less than a predetermined value.

11. A method comprising the steps of:

(a) releasing an off-coming clutch;

(b) ensuring the release of the off-coming clutch by comparing a first hydraulic pressure with a predetermined hydraulic pressure;

(c) autonomously controlling a throttle opening;

(d) determining the engagement of an on-coming clutch by comparing a second hydraulic pressure with a second predetermined hydraulic pressure; and

,

(e) terminating the autonomous control of the throttle opening substantially simultaneously with the engagement of the on-coming clutch.

12. The method of claim 11, wherein step (c) further comprises the step of:

autonomously controlling the throttle opening by increasing the throttle opening until an engine rotations per minute meets a first engine rotations per minute predetermined value.

13. The method of claim 11, wherein step (b) further comprises the step of:

utilizing a first hydraulic line pressure switch to ensure the release of the off-coming clutch.

14. The method of claim 13, wherein the step of utilizing a first hydraulic line pressure switch to ensure the release of the off-coming clutch, further comprises the step of:

utilizing a timer and a first delay to ensure the release of the off-coming clutch.

15. The method of claim 11, wherein step (d) further comprises the step of:

determining the engagement of the on-coming clutch by comparing a first gear ratio with a first predetermined gear ratio.

16. A vehicle comprising:

a vehicle frame;

an engine;

an automatic transmission, wherein the automatic transmission is mounted to the vehicle frame and operatively connected to the engine;

a control system for use in controlling the engine power when a pressure switch device;

(1) determines that an off-going clutch is substantially released within the automatic transmission; and

, (2) determines when an on-coming clutch is substantially fully engaged within the automatic transmission; and

a throttle control device that;

(1) increases engine power after the off-going clutch is substantially released; and

, (2) reduces engine power at substantially the same time the on-coming clutch is substantially engaged.

17. The vehicle of claim 16 wherein the automatic transmission comprises:

a timer device for causing a first delay, wherein the control system initiates the first delay when the pressure switch device indicates the disengaging of the off-going clutch and the throttle control device reduces engine power at the expiration of the first delay.

18. The vehicle of claim 16 wherein the automatic transmission comprises:

a gear ratio device for determining when the on-coming clutch is substantially fully engaged.

19. The vehicle of claim 18, wherein the gear ratio device determines when the on-coming clutch is substantially fully engaged by comparing a first gear ratio to a second gear ratio.

20. The vehicle of claim 19, wherein the first gear ratio is determined when a first hydraulic line pressure switch changes from a first on state to a first off state and the second gear ratio is determined when a second hydraulic line pressure switch changes from a second off state to a second on state.