Manual downshift control method for automatic transmission

• US 8,771,144 B2
• Filed: 07/21/2008
• Issued: 07/08/2014
• Est. Priority Date: 07/21/2008
• Status: Expired due to Fees

• Current Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Original Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Inventors: Dickinson, Mike, Dorn, Aaron
• Primary Examiner(s): KNIGHT, DEREK DOUGLAS
• Application Number:
  US12/176,455
• Publication Number:
  US 20100016120A1
• Time in Patent Office: 2,178 Days
• Field of Search: 477/107, 477/109
• 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 a vehicle frame, an engine and an automatic transmission that is mounted to the vehicle frame and operatively connected to the engine;

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

(c) triggering an increase in the engine power due to the first hydraulic fluid pressure reaching a first predetermined level;

(d) determining a second hydraulic fluid pressure; and

,

(e) triggering a reduction in the engine power substantially fully due to the second hydraulic fluid pressure reaching 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 6 wherein:

the expiration of the first delay triggers a “

timer expired”

signal; and

the increase in the engine power in step (c) occurs only if the “

timer expired”

signal has also been triggered.

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 greater than a predetermined value.

9. The method of claim 8 wherein the effective gear ratio is determined by comparing a first gear ratio with a second gear ratio;

wherein the first gear ratio is determined during step (b) at the time of and due to the first hydraulic pressure reaching a first predetermined level; and

wherein the second gear ratio is determined during step (d) at the time of and due to the second hydraulic fluid pressure reaching a second predetermined level.

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 substantially equal to or less than a predetermined value.

11. 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.

12. 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.

13. 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 triggered by the off-going clutch becoming substantially released; and

, (2) reduces engine power triggered by the on-coming clutch becoming substantially engaged.

14. The vehicle of claim 13 wherein the automatic transmission comprises:

a timer device for causing a first delay, wherein the control system initiates the first delay due to the pressure switch device indicating the disengaging of the off-going clutch, and wherein the throttle control device increases engine power due to the expiration of the first delay.

15. The vehicle of claim 13 wherein the automatic transmission comprises:

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

16. The vehicle of claim 15, 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.

17. The vehicle of claim 16, 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.