Gearshift controlling system for vehicle automatic transmission

• US 5,681,240 A
• Filed: 02/29/1996
• Issued: 10/28/1997
• Est. Priority Date: 03/02/1995
• Status: Expired due to Term

• Current Assignee: Honda Giken Kogyo Kabushiki Kaisha (Honda Motor Company)
• Original Assignee: Honda Giken Kogyo Kabushiki Kaisha (Honda Motor Company)
• Inventors: Sunada, Satoru, Tanizawa, Shoichi
• Primary Examiner(s): Wright, Dirk
• Application Number:
  US08/610,137
• Time in Patent Office: 607 Days
• Field of Search: 477/125, 477/906
• US Class Current: 477/125
• CPC Class Codes: F16H 2061/122 Avoiding failures by using redundant parts
• CPC Class Codes: F16H 2061/1284 the failing part is a sensor
• CPC Class Codes: F16H 59/24 dependent on the throttle opening
• CPC Class Codes: F16H 61/0213 characterised by the method for generating shift signals
• CPC Class Codes: F16H 61/12 Detecting malfunction or potential malfunction, e.g. fail safe in control of hydrostatic gearing F16H61/4192; Circumventing or fixing failures
• CPC Class Codes: F16H 61/682 with interruption of drive
• CPC Class Codes: Y10S 477/906 Means detecting or ameliorating the effects of malfunction or potential malfunction

Abstract

A gearshift controlling system for controlling a vehicle automatic transmission. In the system, a first alternative throttle opening degree is predetermined in case of failure of a throttle position sensor, and a second alternative throttle opening is similarly determined such that a gear ratio can be determined based on the detected vehicle speed and the second alternative engine load in a gear ratio decreasing or increasing direction. Either of the first alternative throttle opening degree or the second alternative throttle opening is selected and the gear ratio to be shifted to is determined in accordance with the predetermined gearshift schedule based on the detected vehicle speed and the selected alternative engine load, to output the gearshift command, thereby preventing unexpected gearshift to occur.

Claims

1. An improved gearshift controlling system for a vehicle automatic transmission, comprising:

a vehicle speed detecting means for detecting a vehicle speed;

an engine load detecting means for detecting an engine load; and

gearshift command output means for determining a gear ratio to be shifted to in accordance with a predetermined gearshift schedule based on the detected vehicle speed and the engine load, to output a gearshift command,

the improvement comprising;

gear ratio detecting means for detecting a current gear ratio;

alternative engine load determining means for determining an alternative engine load in case of failure of said engine load detecting means in response to at least the detected current gear ratio such that said gearshift command output means determines a same gear ratio as is currently selected based on the detected vehicle speed and the alternative engine load; and

said gearshift command output means determines the gear ratio to be shifted to in accordance with the predetermined gearshift schedule based on the detected vehicle speed and the alternative engine load, to output the gearshift command.

2. An improved gearshift controlling system according to claim 1, wherein said engine load detecting means detects the engine load through a throttle opening degree of the engine.

3. An improved gearshift controlling system for a vehicle automatic transmission, comprising:

a vehicle speed detecting means for detecting a vehicle speed;

an engine load detecting means for detecting an engine load; and

gearshift command output means for determining a gear ratio to be shifted to in accordance with a predetermined gearshift schedule based on the detected vehicle speed and the engine load, to output a gearshift command,

the improvement comprising;

first alternative determining means for determining a first alternative engine load in case of failure of said engine load detecting means;

second alternative determining means for determining a second alternative engine load, which is equal to or less than a predetermined value, in a direction other than that in which the gear ratio is decreased in case of failure of said engine load detecting means;

comparing means for comparing the first alternative engine load with the second alternative engine load to select a smaller of the first alternative engine load and the second alternative engine load; and

said gearshift command output means determines the gear ratio to be shifted to in accordance with the predetermined gearshift schedule based on the detected vehicle speed and the selected alternative engine load, to output the gearshift command.

4. An improved gearshift controlling system according to claim 3, wherein said second alternative determining means determines the second alternative engine load to a value as large as possible to an extent that said gearshift command output means determines a gear ratio in a direction other than that in which the gear ratio is decreased.

5. An improved gearshift controlling system according to claim 3, wherein the second alternative engine load is a variable value determined with respect to the vehicle speed and the gear ratio.

6. An improved gearshift controlling system according to claim 3, wherein said engine load detecting means detects the engine load through a throttle opening degree of the engine.

7. An improved gearshift controlling system for a vehicle automatic transmission, comprising;

a vehicle speed detecting means for detecting a vehicle speed;

an engine load detecting means for detecting an engine load; and

gearshift command output means for determining a gear ratio to be shifted to in accordance with a predetermined gearshift scheduled based on the detected vehicle speed and the engine load, to output a gearshift command,

the improved comprising;

first alternative determining means for determining a first alternative engine load in case of failure of said engine load means;

second alternative determining means for determining a second alternative engine load, which is equal to or greater than a predetermined value, in a direction other than that in which the gear ratio is increased in case of failure of said engine load detecting means;

comparing means for comparing the first alternative engine load with the second alternative engine load to select a larger of the first alternative engine load and the second alternative engine load; and

said gearshift command output means determines the gear ratio to be shifted to in accordance with the predetermined gearshift schedule based on the detected vehicle speed and the selected alternative engine load to output the gearshift command.

8. An improved gearshift controlling system according to claim 7, wherein said second alternative determining means determines the second alternative engine load to a value as small as possible to an extent that said gearshift command output means determines a gear ratio in a direction other than that in which the gear ratio is increased.

9. An improved gearshift controlling system according to claim 7, wherein the second alternative engine load is a variable value determined with respect to the vehicle speed and the gear ratio.

10. An improved gearshift controlling system according to claim 7, wherein said engine load detecting means detects the engine load through a throttle opening degree of the engine.