CN-116624585-B - Gear shifting control method and device for auxiliary brake on of AT (automatic Transmission)

CN116624585BCN 116624585 BCN116624585 BCN 116624585BCN-116624585-B

Abstract

The application relates to a gear shifting control method and a gear shifting control device for an AT transmission when auxiliary braking is started, which are used for calculating the lowest gear which the transmission is allowed to drop under the current working condition according to the rotation speed signal of an output shaft of the transmission and the rotation speed of a rated power point of an engine, taking the lowest gear as a target gear for gear shifting control, increasing the rotation speed of the engine to the vicinity of the rated rotation speed after the gear shifting of the AT transmission, enabling the engine to be in a high rotation speed area, enhancing the braking effect of the engine, adopting a new gear shifting strategy to increase the gear shifting point of the transmission when the auxiliary braking is started, rapidly increasing the rotation speed of the engine and keeping the engine in the high rotation speed area, simultaneously accelerating the oil charge of a retarder, rapidly establishing braking torque, improving the braking effect of the auxiliary braking and effectively protecting the safety of vehicles and personnel.

Inventors

ZHAO HUIQIANG
LI MING
CHEN GANGZHI
ZHU JUN
ZHANG JIAN
GAO XIAOZHEN
LI BO
HOU LIANJUN
WANG HU
SUN WEI
WANG LE
Mu Yongyong

Assignees

西安双特智能传动有限公司

Dates

Publication Date: 20260505
Application Date: 20230615

Claims (8)

1. A shift control method when auxiliary brake of an AT transmission is turned on, comprising: Calculating the allowable lowest gear GearY of the transmission according to the rotation speed of the output shaft of the transmission and the rotation speed of the rated power point of the engine; When the auxiliary brake is started, judging whether the current gear of the transmission is larger than the allowable lowest gear GearY; if the current gear of the transmission is greater than the allowable minimum gear GearY, reducing the current gear of the transmission to the allowable minimum gear GearY; When the exhaust braking torque of the engine is larger than the first limit value and the set duration is continuous, or the braking torque of the retarder is larger than the second limit value and the set duration is continuous, adjusting the gear shifting point of the transmission to obtain a new gear shifting point; Judging whether the current gear is larger than a target gear GearX; If the current gear is greater than the target gear GearX, the current gear is reduced to the target gear GearX according to the new gear shift point; wherein, according to derailleur output shaft rotational speed, engine rated speed, calculate the minimum gear GearY that the derailleur allows, include: Step S11, setting the lowest gear GearY allowed by the transmission as the default highest gear of the transmission; Step S12, calculating the highest allowable transmission output shaft rotation speed R, r=engine rated power point rotation speed/GearY-1 gear speed ratio; Step S13, judging whether the current transmission output shaft rotating speed is smaller than the highest allowable transmission output shaft rotating speed R, if yes, executing step S14, and if not, executing step S15; step S14, updating the lowest gear GearY allowed by the transmission to GearY-1 gear, and recording as Calculating the highest allowable transmission output shaft speed at that time , =Engine rated power point speed +. -1 Gear ratio, returning to step S13; In step S15, it is determined whether the lowest gear GearY allowed by the transmission is smaller than the target gear GearX, if yes, the lowest gear GearY allowed by the transmission is equal to the target gear GearX, and if not, the lowest gear GearY allowed by the transmission is output.
2. The method of claim 1, wherein adjusting the transmission shift point comprises increasing an output shaft speed at the upshift point.
3. The method of claim 1, wherein the first limit is 0N/m, the second limit is 0N/m, and the set time period is 2s.
4. A shift control device when an auxiliary brake of an AT transmission is turned on, comprising: The lowest gear calculation module is used for calculating the allowable lowest gear GearY of the transmission according to the rotation speed of the output shaft of the transmission and the rotation speed of the rated power point of the engine; The first judging module is used for judging whether the current gear of the transmission is larger than the allowable lowest gear GearY when the auxiliary brake is started; A first downshift module configured to lower the current gear of the transmission to the allowable lowest gear GearY if the current gear of the transmission is greater than the allowable lowest gear GearY; The gear shifting point adjusting module is used for adjusting the gear shifting point of the transmission to obtain a new gear shifting point when the exhaust braking torque of the engine is larger than a first limit value and lasts for a set period of time, or the braking torque of the retarder is larger than a second limit value and lasts for a set period of time; The second judging module is used for judging whether the current gear is larger than the target gear GearX; The second downshift module is configured to, if the current gear is greater than the target gear GearX, lower the current gear to the target gear GearX according to the new shift point; the lowest gear calculation module is further used for realizing the following functions: Step S11, setting the lowest gear GearY allowed by the transmission as the default highest gear of the transmission; Step S12, calculating the highest allowable transmission output shaft rotation speed R, r=engine rated power point rotation speed/GearY-1 gear speed ratio; Step S13, judging whether the current transmission output shaft rotating speed is smaller than the highest allowable transmission output shaft rotating speed R, if yes, executing step S14, and if not, executing step S15; step S14, updating the lowest gear GearY allowed by the transmission to GearY-1 gear, and recording as Calculating the highest allowable transmission output shaft speed at that time , =Engine rated power point speed +. -1 Gear ratio, returning to step S13; In step S15, it is determined whether the lowest gear GearY allowed by the transmission is smaller than the target gear GearX, if yes, the lowest gear GearY allowed by the transmission is equal to the target gear GearX, and if not, the lowest gear GearY allowed by the transmission is output.
5. The apparatus of claim 4, wherein the shift point adjustment module is further configured to increase the rotational speed of the output shaft when the shift point is raised.
6. The apparatus of claim 4, wherein the first limit is 0N/m, the second limit is 0N/m, and the set time period is 2s.
7. A computer readable storage medium, characterized in that the computer readable storage medium stores a computer program which, when executed by a processor, implements the shift control method AT the time of AT transmission auxiliary brake on according to any one of claims 1-3.
8. A computer program product comprising computer program/instructions which, when executed by a processor, implement the shift control method AT the time of AT transmission auxiliary brake on as claimed in any one of claims 1-3.

Description

Gear shifting control method and device for auxiliary brake on of AT (automatic Transmission) Technical Field The application relates to the field of transmission control, in particular to a gear shift control method and device for auxiliary braking on an AT transmission. Background When a cargo or passenger carrying vehicle is in a long downhill working condition, the brake system is easy to heat fade due to long-time working of the brake requirement, and potential safety hazards exist, so that the vehicle is provided with a plurality of auxiliary brake systems, such as engine exhaust brake and a hydraulic retarder, which play a role in auxiliary brake deceleration and can release the brake pressure of the brake system to a certain extent, but the auxiliary brake systems have the following defects that 1, the engine exhaust brake is directly related to the engine rotating speed, the brake torque is weak in a low rotating speed area of the engine, the brake effect is poor, and 2, the hydraulic retarder is in hydraulic transmission, so that the establishment of the brake torque is lagged when the hydraulic retarder works, and the front-stage brake effect is weak. Disclosure of Invention In order to overcome AT least one of the defects in the prior art, the application provides a gear shift control method and a gear shift control device for an AT transmission when auxiliary braking is started. In a first aspect, a shift control method for an AT transmission auxiliary brake on is provided, including: Calculating the allowable lowest gear GearY of the transmission according to the rotation speed of the output shaft of the transmission and the rotation speed of the rated power point of the engine; when the auxiliary brake is started, judging whether the current gear of the transmission is larger than the allowable lowest gear GearY; if the current gear of the transmission is greater than the allowable minimum gear GearY, the current gear of the transmission is reduced to the allowable minimum gear GearY; When the exhaust braking torque of the engine is larger than the first limit value and the set duration is continuous, or the braking torque of the retarder is larger than the second limit value and the set duration is continuous, adjusting the gear shifting point of the transmission to obtain a new gear shifting point; Judging whether the current gear is larger than a target gear GearX; If the current gear is greater than the target gear GearX, the current gear is reduced to the target gear GearX according to the new shift point. In one embodiment, calculating the minimum allowable transmission gear GearY from the transmission output shaft speed, the engine rated speed, includes: Step S11, setting the lowest gear GearY allowed by the transmission as the default highest gear of the transmission; Step S12, calculating the highest allowable transmission output shaft rotation speed R, r=engine rated power point rotation speed/GearY-1 gear speed ratio; Step S13, judging whether the current transmission output shaft rotating speed is smaller than the highest allowable transmission output shaft rotating speed R, if yes, executing step S14, and if not, executing step S15; Step S14, updating the lowest allowable gear GearY of the transmission to GearY-1 gear, recording as GearY ′, calculating the highest allowable transmission output shaft rotating speed R, R=engine rated power point rotating speed/GearY ′ -1 gear speed ratio at the moment, and returning to the step S13; In step S15, it is determined whether the lowest gear GearY allowed by the transmission is smaller than the target gear GearX, if yes, the lowest gear GearY allowed by the transmission is equal to the target gear GearX, and if not, the lowest gear GearY allowed by the transmission is output. In one embodiment, adjusting the transmission shift point includes increasing the output shaft speed at the upshift point. In one embodiment, the first limit is 0N/m, the second limit is 0N/m, and the set duration is 2s. In a second aspect, there is provided a shift control device when an AT transmission auxiliary brake is on, comprising: The lowest gear calculation module is used for calculating the allowable lowest gear GearY of the transmission according to the rotation speed of the output shaft of the transmission and the rotation speed of the rated power point of the engine; The first judging module is used for judging whether the current gear of the transmission is larger than the allowable lowest gear GearY when the auxiliary brake is started; A first downshift module configured to lower the current gear of the transmission to a lowest allowable gear GearY if the current gear of the transmission is greater than the lowest allowable gear GearY; The gear shifting point adjusting module is used for adjusting the gear shifting point of the transmission to obtain a new gear shifting point when the exhaust braking torque of the engine is larger than a first limit v