Vehicle transmission torque control method and system and engineering vehicle

Abstract

The invention relates to a vehicle transmission torque control method and system and an engineering vehicle, and the control method comprises the steps: confirming the speed ratio of a gearbox, confirming the gear of the gearbox, limiting the torque of an engine, delaying the judgment time by setting the gear, and if the time of the gearbox at the gear does not exceed the judgment time, starting the engine; if yes, the gear determined according to the speed ratio range and the gear determined at the last moment are smaller and serve as the current gear of the gearbox; the control system comprises a gearbox speed ratio calculation module, a gearbox gear confirmation module, a gear protection module and an engine torque limiting module. The engineering vehicle is provided with the control system. According to the method, gear judgment and engine output torque limiting are carried out on the engineering vehicle provided with the manual box, and the gear judgment method is simple, accurate in gear judgment, low in cost and high in safety.

Description

Technical Field

[0001] The present invention belongs to the technical field of vehicle transmission control, and particularly relates to a vehicle transmission torque control method, system and engineering vehicle. Background Art

[0002] The vehicle transmission system has functions such as starting, shifting, torque conversion, and differential of the vehicle, providing sufficient traction and speed change for the moving vehicle, thereby ensuring the safety of the moving vehicle and achieving stable operation and riding. The vehicle transmission system consists of a clutch, a torque converter, a gearbox, a transfer case, a drive shaft, a drive axle, etc. The power output by the engine is transmitted to the drive wheels through the torque conversion and speed change of the clutch, torque converter, gearbox, and transfer case, and then through the drive shaft, main reducer, differential, and half shaft. The transmission system of an engineering vehicle can be divided into a transmission system with a transfer case and a transmission system without a transfer case.

[0003] In the transmission system, the combined output torque of the engine and the gearbox is different in different gears, and different components in the transmission system have different bearing capacities for the input torque. The combined output torque of the engine and the gearbox may be greater than the maximum allowable input torque of transmission system parts such as the drive shaft, transfer case, or axle, resulting in part damage and even safety accidents. Therefore, it is necessary to limit the combined output torque of the engine and the gearbox. Since the origin of power output is the engine, it is required to limit the torque of the engine according to the input torque of different components in different gearbox gears. In some vehicles, in order to achieve fuel saving or protect the engine, it is also necessary to limit the engine output torque in different gearbox gears.

[0004] The gearbox can be divided into an automatic gearbox and a manual gearbox: the automatic gearbox can automatically shift gears according to the vehicle speed and engine speed; the engine can identify the gear of the automatic gearbox through the system message and limit the output torque of different gears according to the set values. The manual gearbox is a mechanical device that realizes gear shifting by the driver operating the shift lever. There is no interaction between the manual gearbox and the vehicle, and the gearbox gear cannot be automatically recognized, so it is impossible to limit the torque of the engine in different gears, which easily causes damage to the transmission system parts and even safety accidents. In the prior art, by adding a space attitude acquisition device or calculating the gear to judge the manual gearbox gear, on the one hand, it increases the sensor device, resulting in an increase in cost; on the other hand, the error in calculating and judging the manual gearbox gear is relatively large, and the engine output torque cannot be matched and limited, leading to easy damage to the transmission system parts. Especially for engineering vehicles with high loads, they need to be frequently repaired. If problems occur during operation, accidents are likely to occur, and the safety risk is relatively high.

[0005] Patent application CN115182995A discloses a method and system for judging the gear position of a manual transmission motor vehicle. First, determine the gear ratio intervals of all gear positions for forward and reverse gears; determine the gear ratio interval in which the instantaneous gear ratio is located; after determining the gear ratio interval in which the instantaneous gear ratio is located, judge the duration of the gear position. If the duration of the gear position is greater than the set time, the number of gear positions corresponding to the gear ratio interval is the current gear position of the transmission; if the duration of the gear position is less than or equal to the set time, determine that the current gear position of the transmission is the gear position determined at the previous moment. This technical solution, without increasing additional equipment costs, determines the gear ratio intervals by calculating the gear ratios of all gear positions of the transmission, and determines the manual transmission gear position based on the duration of the instantaneous gear ratio in the corresponding speed ratio interval, realizing the judgment and identification of the gear position of the manual transmission. However, in actual situations such as rapid downshifting, frequent gear shifting, short-term incorrect gear shifting, and misoperation of gear shifting, that is, when the duration of the instantaneous gear ratio in the corresponding speed ratio interval is short, if it is still determined to maintain the gear position at the previous moment, the engine output torque will still be output in the state of the previous gear position, and there will still be problems of mismatch or excessive difference between the output torque and the actual gear position, thus causing damage to the transmission system parts and still posing a safety hazard.

[0006] Therefore, there is an urgent need for a vehicle transmission torque control method, system and engineering vehicle with a simple manual transmission gear position judgment method, accurate gear position judgment, precise engine torque control, low cost and high safety. Summary of the Invention

[0007] The object of the present invention is to overcome the above deficiencies and provide a vehicle transmission torque control method, system and engineering vehicle with a simple manual transmission gear position judgment method, accurate gear position judgment, precise engine torque control, low cost and high safety.

[0008] The object of the present invention is achieved as follows:

[0009] A vehicle transmission torque control method includes the following steps:

[0010] Step S100, confirm the transmission gear ratio

[0011] S101, after the vehicle is ignited and powered on, read the signal of the transmission neutral gear sensor to confirm whether the transmission is in neutral;

[0012] S102, when it is confirmed that the transmission is not in neutral, judge whether the transmission gear position is in the forward gear or the reverse gear through the reverse gear switch signal;

[0013] S103, according to the calculation formula: transmission gear ratio = engine output speed ÷ transmission output speed, calculate the transmission gear ratio;

[0014] Step S200, confirm the transmission gear position

[0015] S201. Calculate the upper and lower limit values of the gear ratios of different gears of the gearbox to obtain the gear ratio ranges corresponding to different gears.

[0016] S202. Set the gear delay judgment time T.

[0017] S203. Determine the gear of the gearbox: If the time of the gearbox in the gear exceeds T, and the current gear ratio calculated by S103 falls within the gear ratio range of the corresponding gear obtained through S201, then determine the current gear of the gearbox; if the time of the gearbox in the gear does not exceed T, also take the smaller one of the gear determined by the gear ratio range and the gear determined at the previous moment as the current gear of the gearbox.

[0018] Step S300. Limit the engine torque

[0019] Limit the engine output torque according to the result of the current gear of the gearbox determined in step S200.

[0020] Furthermore, the output speed of the gearbox in step S103 is obtained by a speed sensor installed on the output shaft of the gearbox.

[0021] Furthermore, the upper and lower limit values of the gear ratios of each gear of the gearbox in step S201 are determined by the following formula:

[0022] , , where is the upper limit value of the selected gear ratio; is the lower limit value of the selected gear ratio; is the gear ratio value of the previous gear; is the gear ratio value of the selected gear; is the gear ratio value of the next gear.

[0023] Furthermore, each gear of the gearbox in step S201 includes the first forward gear and the first reverse gear. The upper limit value of the gear ratios of the first forward gear and the first reverse gear takes twice the gear ratio of this gear, and the lower limit value takes the average value of the gear ratios of the first gear and the second gear, that is , .

[0024] Furthermore, each gear of the gearbox in step S201 includes the highest forward gear and the highest reverse gear. The upper limit value of the gear ratios of the highest forward gear and the highest reverse gear takes the average value of the sum of the gear ratios with the previous gear, and the lower limit value takes 0, that is , ).

[0025] Further, in step S300, the output torque of the engine is restricted by a torque limit curve: at the same engine speed, the torque of the torque limit curve is compared with the engine's external characteristic torque, and the minimum torque value of the two is determined as the maximum output torque of the engine at that speed; the engine identifies the current gear of the transmission and restricts the torque of the engine at that speed not to exceed the maximum output torque at the corresponding speed.

[0026] Further, in step S300, the output torque of the engine is restricted by a percentage of the engine reference torque: the torque limit values of the engine in different gears are calculated in advance to obtain the percentage of the limit value to the reference torque; the vehicle control unit identifies the current gear of the transmission, sends a message, and controls the engine to output torque according to the percentage of the reference torque to ensure the restriction effect of the engine's output torque.

[0027] A vehicle transmission torque control system, characterized in that: the vehicle transmission torque control system uses any of the vehicle transmission torque control methods for transmission torque control, and includes a transmission ratio calculation module, a transmission gear confirmation module, a gear protection module, and an engine torque limit module;

[0028] The transmission ratio calculation module: obtains the engine output speed and the transmission output speed, and calculates the ratio of the two to obtain the current transmission ratio;

[0029] The transmission gear confirmation module: pre-calculates and stores the upper and lower limit values of the transmission ratio of each gear; according to the current transmission ratio obtained by the transmission ratio calculation module, compares it with the upper and lower limit values of the transmission ratio of each gear to determine the current gear of the transmission;

[0030] The gear protection module: sets a gear delay judgment time. If the time in the gear exceeds the judgment time, the gear determined by the transmission gear confirmation module is the current gear of the transmission; if the time in the gear does not exceed the judgment time, take the smaller of the gear determined by the transmission gear confirmation module and the gear determined at the previous moment as the current gear of the transmission;

[0031] The engine torque limit module: restricts the output torque of the engine according to the current gear of the transmission determined by the gear protection module.

[0032] Further, the engine torque limit module restricts and controls the output torque of the engine according to the engine output torque limit curve or the engine reference torque percentage.

[0033] An engineering vehicle is equipped with any of the vehicle transmission torque control systems to control the output torque of the engine.

[0034] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0035] The vehicle transmission torque control method of the present invention calculates the speed ratio through the rotational speed of the output shaft of the gearbox and the output rotational speed of the engine, determines the current speed ratio according to the pre-set speed ratio ranges for different gears, does not require adding an additional system, has strong versatility and low cost; sets a gear shift delay judgment time. If the time of the gearbox in a gear does not exceed the judgment time, determine the smaller of the gear determined by passing through the speed ratio range and the gear determined at the previous moment as the current gear of the gearbox, ensuring that the engine output matches the low torque of the low gear, protecting the transmission system parts, reducing the maintenance cost of the parts, increasing the service life, improving the operation safety, and also reducing fuel consumption through torque limitation to improve the economy of the vehicle;

[0036] The vehicle transmission torque control system of the present invention uses the vehicle transmission torque control method to judge and identify the current gear of the gearbox, and correspondingly limits the engine output torque according to the identified gear, and correspondingly sets the respective operation modules to complete the identification and judgment of the current gear of the gearbox and limit the engine output torque;

[0037] The engineering vehicle of the present invention is equipped with the vehicle transmission torque control system to control the engine output torque, protect the transmission system parts, and has high operation safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 is a working flow chart of a vehicle transmission torque control method of the present invention.

[0039] Figure 2 is a structural schematic diagram of a vehicle transmission torque control system of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0040] Example 1:

[0041] See Figure 1 , a vehicle transmission torque control method involved in the present invention includes the following steps:

[0042] Step S100, confirm the gearbox speed ratio

[0043] S101, after the vehicle is ignited and powered on, first read the signal of the gearbox neutral sensor to confirm whether the gearbox is in neutral; if the gearbox is in neutral, maintain the current state;

[0044] S102, when it is confirmed that the gearbox is not in neutral, judge whether the gear of the gearbox is in the forward gear or the reverse gear through the reverse gear switch signal;

[0045] S103. Calculate the transmission ratio according to the calculation formula: transmission ratio = engine output speed ÷ transmission output speed. If the transmission is in the forward gear, calculate the current gear ratio of the forward gear according to this formula; if the transmission is in the reverse gear, calculate the current gear ratio of the reverse gear accordingly.

[0046] The transmission output speed is obtained by calculating through a speed sensor installed on the transmission output shaft at the rear end of the transmission. Since the output signal of the sensor is a pulsed signal, the calculation formula for the output shaft speed is:

[0047] Speed (rpm) = (number of pulses ÷ counting time) × 60 ÷ (number of pulses per revolution)

[0048] Among them, the number of pulses is the number of pulses emitted by the sensor within a period of time, the counting time is the time used to measure the number of pulses, and the number of pulses per revolution is the number of pulses emitted when the output shaft rotates one circle.

[0049] Step S200. Confirm the transmission gear

[0050] S201. Calculate the upper and lower limit values of the transmission ratio for different gears to obtain the speed ratio range corresponding to different gears.

[0051] The upper and lower limit values of the transmission ratio for each gear of the transmission are determined by the following formula:

[0052] ,

[0053] Among them, is the upper limit value of the selected gear ratio; is the lower limit value of the selected gear ratio; is the speed ratio value of the previous gear; is the speed ratio value of the selected gear; is the speed ratio value of the next gear;

[0054] At the same time, each gear of the transmission also includes the first forward gear and the first reverse gear, the highest forward gear and the highest reverse gear; the upper limit value of the speed ratio of the first forward gear and the first reverse gear takes twice the speed ratio of this gear, and the lower limit value takes the average value of the speed ratios of the first gear and the second gear, that is , ; the upper limit value of the speed ratio of the highest forward gear and the highest reverse gear takes the average value of the sum of the speed ratios with the previous gear, and the lower limit value takes 0, that is , ;

[0055] S202. Set the gear delay judgment time T.

[0056] S203. Determine the transmission gear: If the time the transmission is in gear exceeds T, the current gear ratio calculated by S103 falls within the gear ratio range of the corresponding gear obtained through S201 to determine the current transmission gear; if the time the transmission is in gear does not exceed T, the gear determined by the gear ratio range and the gear determined at the previous moment are compared, and the smaller one is taken as the current transmission gear;

[0057] Under different gears of the transmission, the torque limit of the drive system is different. When the transmission is in a lower gear, the gear ratio is larger, and at this time, the limit on the engine output torque is greater. To more accurately identify the gear and better protect the torque of the drive system, the following regulations are made: Set the gear shift delay judgment time T. If the time in gear exceeds the judgment time, the gear determined by the above gear ratio range is the current transmission gear; if the time the transmission is in gear does not exceed the judgment time, determine the gear determined by the gear ratio range and the gear determined at the previous moment, and take the smaller one as the current transmission gear;

[0058] When encountering actual working conditions such as rapid downshifting, frequent shifting, short-term wrong gear shifting, and misoperation of gear shifting, that is, the duration of the instantaneous gear ratio in the gear ratio interval is short and does not exceed the judgment time, then determine the current gear and the gear at the previous moment, and take the smaller one as the current gear. In this way, the engine output torque will be limited according to the lower gear of the two gears, so as to ensure that the engine output torque is in the low torque state corresponding to the low gear, thereby protecting the drive train parts and ensuring the safety of the engineering vehicle operation.

[0059] Step S300. Limit the engine torque

[0060] According to the result of the current transmission gear determined in step S200, limit the engine output torque. In this embodiment, the output torque of the generator can be limited by a torque limit curve or a percentage of the engine reference torque. Specifically:

[0061] Limit the engine output torque through a torque limit curve: At the same engine speed, compare the torque of the torque limit curve with the engine external characteristic torque, and the minimum torque value of the two is determined as the maximum engine output torque at that speed; the engine identifies the current transmission gear and limits the torque of the engine at that speed not to exceed the maximum output torque at the corresponding speed;

[0062] Limit the engine output torque through a percentage of the engine reference torque: Calculate in advance the torque limit values of the engine under different gears, and obtain the percentage of this limit value to the reference torque; the vehicle controller identifies the current gear of the transmission, sends a message, and controls the engine to output torque according to the percentage of the reference torque to ensure the limit effect of the engine output torque.

[0063] In addition, the method for identifying and judging the current gear of the transmission involved in this embodiment can be applied not only to controlling the output torque of the power transmission system, but also to functions such as reducing fuel consumption, controlling vehicle speed, and limiting the turning radius.

[0064] Embodiment 2:

[0065] See Figure 2 , a vehicle transmission torque control system according to the present invention includes a transmission ratio calculation module, a transmission gear confirmation module, a gear protection module, and an engine torque limitation module; the vehicle transmission torque control system uses the vehicle transmission torque control method of Embodiment 1 to judge and identify the current gear of the transmission, and correspondingly limit the engine output torque according to the identified gear. The working processes of specific modules are as follows:

[0066] The transmission ratio calculation module: obtains the engine output speed and the transmission output speed, and calculates the ratio of the two to obtain the current transmission ratio;

[0067] In this embodiment, the transmission output speed is obtained by calculating through a speed sensor installed on the transmission output shaft at the rear end of the transmission; since the output signal of the sensor is a pulsed signal, the output shaft speed calculation formula is:

[0068] Speed (rpm) = (number of pulses ÷ counting time) × 60 ÷ (number of pulses per revolution)

[0069] Among them, the number of pulses refers to the number of pulses emitted by the sensor within a period of time, the counting time is the time used to measure the number of pulses, and the number of pulses per revolution refers to the number of pulses emitted by the output shaft per revolution;

[0070] The transmission gear confirmation module: pre-calculates and stores the upper and lower limits of the transmission ratio of each gear. The calculation unit in this module automatically calculates and stores the upper and lower limits of the transmission ratio of each gear according to the transmission parameters, or directly inputs the calculated upper and lower limits of the transmission ratio of each gear into this module as the basis for judging the current gear ratio; compares the current transmission ratio obtained by the transmission ratio calculation module with the upper and lower limits of the transmission ratio of each gear stored in this module. If the current gear ratio falls within the upper and lower limits of the transmission ratio of a certain gear, it is judged that the current gear of the transmission is the transmission gear corresponding to the upper and lower limit range, thereby determining the current gear of the transmission;

[0071] The gear protection module: sets a gear delay judgment time. If the time in a gear exceeds the judgment time, the gear determined by the transmission gear confirmation module is the current gear of the transmission; if the time in a gear does not exceed the judgment time, the smaller of the gear determined by the transmission gear confirmation module and the gear determined at the previous moment is used as the current gear of the transmission;

[0072] When encountering actual working conditions such as rapid downshifting, frequent shifting, short-term wrong gear shifting, and misoperation of gear shifting, that is, the duration of the instantaneous gear ratio in the current gear ratio range is short and does not exceed the judgment time, the current gear and the gear at the previous moment are determined, and the smaller of the two is taken as the current gear. In this way, the engine output torque is limited according to the lower gear of the two gears, so as to ensure that the engine output torque is in the low torque state corresponding to the lower gear, thereby protecting the transmission parts and ensuring the safety of the engineering vehicle operation;

[0073] The engine torque limitation module: limits the output torque of the engine according to the current gear of the gearbox determined by the gear protection module; in this embodiment, the output torque of the engine can be limited and controlled in the manner of the engine output torque limitation curve or the engine reference torque percentage; due to the accuracy of gear recognition and judgment and the selection of the lower gear under special working conditions, it is ensured that the engine output torque does not exceed the safe transmission torque of the current gear of the gearbox, preventing damage to the transmission parts and improving the operation safety of the engineering vehicle.

[0074] Embodiment 3:

[0075] An engineering vehicle involved in the present invention is equipped with the vehicle transmission torque control system of Embodiment 2, which controls the engine output torque, protects the transmission parts, reduces the part maintenance cost, improves the service life, improves the operation safety, and can also reduce the fuel consumption through torque limitation and improve the economy of the vehicle.

[0076] The present invention has a wide application range. In the fields of engineering vehicles, construction machinery, and even passenger vehicles, for the power transmission system equipped with a manual transmission, the torque limitation of the power transmission system can be realized through the present invention; through the recognition of the gearbox gears, it is not limited to the torque limitation of the power transmission system, but can also be extended to many fields such as limiting the vehicle speed, limiting the turning radius, controlling the fuel consumption, and analyzing the driving behavior (such as low gear with high speed, high gear with low speed).

[0077] In addition: It should be noted that the above specific implementation manners are only an optimized solution of this patent, and any modifications or improvements made by those skilled in the art according to the above concepts are within the protection scope of this patent.

Claims

1. A vehicle transmission torque control method, characterized in that: It includes the following steps: Step S100, confirm the transmission ratio S101, after the vehicle is ignited and powered on, read the signal of the transmission neutral gear sensor to confirm whether the transmission is in neutral; S102, when it is confirmed that the transmission is not in neutral, judge whether the transmission gear is in the forward gear or the reverse gear through the reverse gear switch signal; S103, according to the calculation formula: transmission ratio = engine output speed ÷ transmission output speed, calculate the transmission ratio; Step S200, confirm the transmission gear S201, calculate the upper and lower limits of the transmission ratio of different gears, and obtain the speed ratio range corresponding to different gears; S202, set the gear delay judgment time T; S203, judge the transmission gear: if the time of the transmission in the gear exceeds T, the current gear ratio calculated by S103 falls within the speed ratio range of the corresponding gear obtained by S201 to determine the current transmission gear; If the time of the transmission in the gear does not exceed T, the gear determined by the speed ratio range and the gear determined at the previous moment are compared, and the smaller one is used as the current transmission gear; Step S300, limit the engine torque According to the result of the current transmission gear determined in step S200, limit the engine output torque.

2. The vehicle transmission torque control method according to claim 1, characterized in that: The transmission output speed in step S103 is obtained by a speed sensor installed on the transmission output shaft.

3. The vehicle transmission torque control method according to claim 1, wherein: The upper and lower limits of the transmission ratio of each gear in step S201 are determined by the following formula: , , where, is the upper limit value of the selected gear ratio; is the lower limit value of the selected gear ratio; is the gear ratio value of the previous gear; is the gear ratio value of the selected gear; is the gear ratio value of the next gear.

4. The vehicle transmission torque control method according to claim 1, characterized in that: In the step S201, each gear of the gearbox includes the first forward gear and the first reverse gear. The upper limit value of the gear ratio of the first forward gear and the first reverse gear is taken as twice the gear ratio of this gear, and the lower limit value is taken as the average value of the sum of the gear ratios of the first gear and the second gear, that is , .

5. The vehicle transmission torque control method according to claim 1, characterized in that: In step S201, each gear of the transmission includes the highest forward gear and the highest reverse gear. The upper limit value of the speed ratio of the highest forward gear and the highest reverse gear is taken as the average value of the sum of the speed ratios of the previous gear, and the lower limit value is taken as 0, that is , .

6. The vehicle transmission torque control method according to claim 1, characterized in that: In step S300, the output torque of the engine is limited by a torque limit curve: at the same engine speed, compare the torque of the torque limit curve with the engine external characteristic torque, and the minimum torque value of the two is determined as the maximum output torque of the engine at this speed; The engine identifies the current transmission gear and limits the torque of the engine at this speed not to exceed the maximum output torque at the corresponding speed.

7. The vehicle transmission torque control method according to claim 1, wherein: In step S300, the output torque of the engine is limited by the percentage of the engine reference torque: calculate in advance the torque limit values of the engine in different gears, and obtain the percentage of this limit value to the reference torque; The vehicle controller identifies the current gear of the transmission, sends a message, and controls the engine to output torque according to the percentage of the reference torque to ensure the limiting effect of the engine output torque.

8. A vehicle transmission torque control system, characterized in that: The vehicle transmission torque control system uses any one of the vehicle transmission torque control methods in claims 1 to 7 for transmission torque control, and includes a transmission ratio calculation module, a transmission gear confirmation module, a gear protection module, and an engine torque limit module; The transmission ratio calculation module: obtains the engine output speed and the transmission output speed, and calculates the ratio of the two to obtain the current transmission ratio; The transmission gear confirmation module: pre-calculates and stores the upper and lower limits of the transmission ratio of each gear of the transmission; compares the current transmission ratio obtained by the transmission ratio calculation module with the upper and lower limits of the transmission ratio of each gear to judge the current transmission gear; The gear protection module: sets a gear delay judgment time. If the time in a gear exceeds the judgment time, the gear determined by the transmission gear confirmation module is the current gear of the transmission; if the time in a gear does not exceed the judgment time, the smaller of the gear determined by the transmission gear confirmation module and the gear determined at the previous moment is taken as the current gear of the transmission. The engine torque limit module: limits the output torque of the engine according to the current gear of the transmission determined by the gear protection module.

9. The vehicle transmission torque control system according to claim 8, wherein: The engine torque limit module controls the limitation of the engine output torque based on the engine output torque limit curve or the engine reference torque percentage.

10. An engineering vehicle, characterized in that: Install the vehicle transmission torque control system according to any one of claims 8 to 9 to control the engine output torque.

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