US 6,547,698 B2Granted

Control system for automatic vehicle transmissions

AssigneeHonda Giken Kogyo Kabushiki Kaisha

InventorsYasushi Inagawa, Satoshi Kato, Masahide Saito, Masamitsu Fukuchi, Yoshikazu Nemoto, Yoshiharu Saito

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Abstract

A system for controlling an automatic transmission of a vehicle, wherein if the change of the destined gear GB (i.e., the target gear SH) is required when the jumping shift, i.e., two-gear downshifting is in progress, the input/output rotational speed ratio GRATIO (indicative of degree of shift progress) is compared with the predetermined input/output rotational speed ratio #GRCN312 or #GRCN423, and based on the result of comparison, how the shift to establish or effect the required destined gear GB, i.e., the shift mode QATNUM is determined, thereby enabling to improve or enhance the response to the change of the destined gear GB during two-gear downshifting. It can also prevent the clutch from being degraded in such a shifting.

Claims10

Dependent claims

A system for controlling an automatic transmission of a vehicle having an input shaft connected to an internal combustion engine mounted on the vehicle and an output shaft connected to driven wheels of the vehicle, the transmission transmitting input torque, through any of frictional engaging elements, generated by the engine and inputted by the input shaft to the driven wheels by the output shaft, comprising;

destined gear retrieving means for retrieving a destined gear to be engaged to in accordance with predetermined shift scheduling map based on detected operating conditions of the vehicle and the engine in response to a shift command;
shift mode determining means for determining a shift mode based on the destined gear and a current gear currently engaged, such that the destined gear is established;
hydraulic pressure command value determining means for determining hydraulic pressure command value to be supplied to any of the frictional engaging elements based on the determined shift mode;
degree of shift progress detecting means for detecting a degree of shift progress in shifting from the current gear to the destined gear;
destined gear change possibility determining means for determining, if the shifting from the current gear to the destined gear is downshifting, whether change of the destined gear is possible when the downshifting is in progress, by comparing the degree of shift progress with a predetermined first threshold value;
destined gear change permission determining means for determining a permission of the change of the destined gear when the change of the destined gear is determined to be possible;
and
destined gear determining means for determining the destined gear based on the permission of the change of the destined gear;
wherein:
the shift mode determining means includes:
second threshold value comparing means for comparing the degree of shift progress with a predetermined second threshold value, when the downshifting is two-gear downshifting;
and determines the shift mode such that the destined gear is established in an upshifting direction.

9 more elements

A method of controlling an automatic transmission of a vehicle having an input shaft connected to an internal combustion engine mounted on the vehicle and an output shaft connected to driven wheels of the vehicle, the transmission transmitting input torque, through any of frictional engaging elements, generated by the engine and inputted by the input shaft to the driven wheels by the output shaft, comprising the steps of;

(a) retrieving a destined gear to be engaged to in accordance with predetermined shift scheduling map based on detected operating conditions of the vehicle and the engine in response to a shift command;
(b) determining a shift mode based on the destined gear and a current gear currently engaged, such that the destined gear is established;
(c) determining hydraulic pressure command value to be supplied to any of the frictional engaging elements based on the determined shift mode;
(d) detecting a degree of shift progress in shifting from the current gear to the destined gear;
(e) determining, if the shifting from the current gear to the destined gear is downshifting, whether change of the destined gear is possible when the downshifting is in progress, by comparing the degree of shift progress with a predetermined first threshold value;
(f) determining a permission of the change of the destined gear when the change of the destined gear is determined to be possible;
and
(g) determining the destined gear based on the permission of the change of the destined gear;
wherein:
the step (b) includes:
(h) comparing the degree of shift progress with a predetermined second threshold value, when the downshifting is two-gear downshifting;
and determines the shift mode such that the destined gear is established in an upshifting direction.

9 more elements

Dependencies are inferred from the claim text.

Facts

Application: 09/983,158Filed 23 Oct 2001
Priority: JP 2000-32414524 Oct 2000
Published: US 2002/0046617 A125 Apr 2002
Granted: 15 Apr 2003
Term ends: Not estimatedThe source records don’t support an estimate.

Classification8 codes

F16H 61/0437
Smoothing ratio shift: by using electrical signals
F16H 61/16
Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid…
F16H 2061/0444
Smoothing ratio shift: during fast shifting over two gearsteps, e.g. jumping from fourth to second gear
F16H 2306/24
Shifting: interruption of shift, e.g. if new shift is initiated during ongoing previous shift