Automatic gearbox gear shifting method

Abstract

The invention relates to an automatic gearbox gear shifting method which comprises the steps that a gearbox controller obtains engine parameters from a whole vehicle control unit through a CAN bus, obtains a gearbox state from a gearbox sensor and reads calibration parameters from gearbox control software, and the optimal target gear of a vehicle is obtained through calculation; the calibration difficulty of the automatic gearbox can be reduced, the workload in the calibration process is reduced, and the calibration quality of the gearbox is improved; power required by the vehicle is calculated in real time, gears meeting the power requirement of the vehicle are screened out, and the power requirement of the vehicle is met; and the gear with the lowest oil consumption is selected from all the proper gears, so that the economical efficiency of the vehicle is improved.

Description

Technical Field

[0001] The present application relates to the field of gearbox shifting, and in particular, to a method for shifting an automatic gearbox. Background Art

[0002] Currently, the target gear of the automatic transmission is selected based on the engine speed. When the engine speed reaches the set shift speed, the automatic transmission enters the shift state, calculates the engine speed after the shift, and selects the target gear based on it. In addition, external conditions such as vehicle weight, ramp, altitude, etc. will also affect the vehicle's shifting. The automatic transmission will compensate for the set shift speed according to the changes in external conditions to ensure that the vehicle has sufficient power after the shift. During the automatic transmission calibration process, the automatic transmission shift speed needs to be calibrated according to the engine characteristics, and compensation calibration is also required for external conditions such as different vehicle weights, ramps, altitudes, etc.

[0003] Nowadays, with the popularity of automatic transmission models, users have higher requirements for automatic transmission shifting strategies. The shifting of automatic transmissions is required to meet the vehicle's power requirements in complex mountainous areas and other road conditions, and also meet the vehicle's fuel economy requirements in good road conditions to save fuel consumption. The OEM also adjusts the engine's characteristics according to the actual vehicle driving conditions through the vehicle control unit (VCU) to achieve the purpose of saving fuel consumption. The adjustment of the engine's characteristics will affect the shifting of the automatic transmission, which is likely to cause insufficient power after shifting. Summary of the invention

[0004] In order to overcome at least one deficiency in the prior art, the present application provides an automatic transmission shifting method.

[0005] In a first aspect, a method for shifting a gear of an automatic transmission is provided, comprising:

[0006] Obtain the current gear of the vehicle, the engine speed at the current gear, and the transmission speed ratio parameters at each gear, and calculate the engine speed corresponding to each gear after the gear shift;

[0007] Obtain the engine torque characteristics, and obtain the maximum engine torque corresponding to each gear through interpolation calculation; determine the engine torque corresponding to each gear after the gear shift according to the relationship between the maximum engine torque corresponding to each gear and the engine torque at the current gear;

[0008] Obtain the vehicle acceleration at the current gear, and calculate the vehicle's current resistance based on the vehicle acceleration at the current gear, the engine torque at the current gear, the tire radius, the powertrain efficiency at the current gear, the vehicle weight, and the wheel angular acceleration; calculate the vehicle acceleration corresponding to each gear after the gear shift based on the vehicle's current resistance, the overall powertrain efficiency, the engine torque corresponding to each gear, and the powertrain speed ratio parameters at each gear;

[0009] Obtaining the expected acceleration range under each throttle opening, determining the gear corresponding to the vehicle acceleration within the acceleration range among the vehicle accelerations corresponding to each gear, to form a first gear set;

[0010] Obtaining the expected engine speed range at each throttle opening, determining the gears in the first gear set that are within the engine speed range, and forming a second gear set;

[0011] Obtaining the engine universal characteristics, and determining the fuel consumption corresponding to each gear in the second gear set according to the engine speed corresponding to each gear, the engine torque corresponding to each gear, and the engine universal characteristics;

[0012] The fuel consumption corresponding to each gear in the second gear set is sorted according to the fuel consumption, and the gear corresponding to the lowest fuel consumption is selected as the target gear for shifting.

[0013] In one embodiment, the engine speed corresponding to each gear position after the gear shift is calculated using the following formula:

[0014]

[0015] Among them, N is the engine speed corresponding to each gear, N Act is the engine speed at the current gear, i Act is the transmission ratio parameter in the current gear, i T It is the transmission ratio parameter under each gear.

[0016] In one embodiment, according to the magnitude relationship between the maximum engine torque corresponding to each gear and the engine torque at the current gear, determining the engine torque corresponding to each gear after the gear shift includes:

[0017] If T maxk ≤T Eng , then T k =T maxk ;

[0018] If T maxk >T Ebg , then T k =T Ebg ;

[0019] Among them, T maxkis the maximum engine torque corresponding to gear k, T Eng is the engine torque at the current gear, T k is the engine torque corresponding to gear k.

[0020] In one embodiment, the current vehicle resistance is calculated according to the vehicle acceleration at the current gear, the engine torque at the current gear, the tire radius, the powertrain efficiency at the current gear, the vehicle weight and the wheel angular acceleration, using the following formula:

[0021]

[0022] Where f is the current resistance of the vehicle, T Eng is the engine torque at the current gear, i Act is the transmission ratio parameter under the current gear, R is the tire radius, η Act is the transmission efficiency at the current gear, m is the vehicle weight, a Act is the vehicle acceleration in the current gear, J is the transmission system moment of inertia converted to the wheels, and α is the wheel angular acceleration.

[0023] In one embodiment, the vehicle acceleration corresponding to each gear after the gear shift is calculated based on the current vehicle resistance, the overall efficiency of the transmission system, the engine torque corresponding to each gear, and the transmission system speed ratio parameters under each gear, using the following formula:

[0024]

[0025] Where a is the vehicle acceleration corresponding to each gear, T is the engine torque corresponding to each gear, and T T is the transpose of T, i T is the transmission ratio parameter under each gear, R is the tire radius, η T is the transmission ratio parameter under each gear, f is the current resistance of the vehicle, m is the vehicle weight, and J is the transmission rotational inertia converted to the wheels.

[0026] In a second aspect, a transmission controller is provided to implement the above-mentioned automatic transmission shifting method.

[0027] In a third aspect, an automatic transmission shifting system is provided, including a transmission controller, a vehicle control unit, and a transmission sensor;

[0028] The vehicle control unit sends the engine speed at the current gear, the engine torque at the current gear, and the engine torque characteristics to the transmission controller;

[0029] The gearbox sensor sends the current gear position of the vehicle and the vehicle acceleration in the current gear position to the gearbox controller;

[0030] The transmission controller is used to implement the above-mentioned automatic transmission shifting method.

[0031] Compared with the prior art, the present application has the following beneficial effects: in the automatic transmission shifting method of the present application, the transmission controller obtains engine parameters from the vehicle control unit through the CAN bus, obtains the transmission status from the transmission sensor, and reads calibration parameters from the transmission control software to calculate the optimal target gear of the vehicle; the present application can reduce the calibration difficulty of the automatic transmission, reduce the workload of the calibration process, and improve the calibration quality of the transmission; calculate the power required by the vehicle in real time, and screen out the gear that meets the power requirements of the vehicle to meet the power requirements of the vehicle; select the gear with the lowest fuel consumption from all suitable gears to improve the economy of the vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The present application may be better understood by referring to the following description given in conjunction with the accompanying drawings, which together with the following detailed description are included in this specification and form a part of this specification. In the drawings:

[0033] Figure 1 A flowchart of an automatic transmission shifting method is shown;

[0034] Figure 2 Shown is a structural block diagram of an automatic transmission shifting system. DETAILED DESCRIPTION

[0035] The exemplary embodiments of the present application will be described below in conjunction with the accompanying drawings. For the sake of clarity and conciseness, not all features of the actual embodiments are described in the specification. However, it should be understood that many implementation-specific decisions can be made in the process of developing any such actual embodiments in order to achieve the specific goals of the developer, and these decisions may vary from embodiment to embodiment.

[0036] It is also necessary to explain here that, in order to avoid obscuring the present application due to unnecessary details, only the device structure closely related to the scheme according to the present application is shown in the drawings, while other details that are not closely related to the present application are omitted.

[0037] It should be understood that the present application is not limited to the described implementation forms due to the following description with reference to the accompanying drawings. In this article, where feasible, the embodiments can be combined with each other, features between different embodiments can be replaced or borrowed, and one or more features can be omitted in one embodiment.

[0038] The present application provides an automatic transmission shifting method. Figure 1 A flowchart of an automatic transmission shifting method is shown in FIG. Figure 1 , methods include:

[0039] Step S1, obtaining the current gear of the vehicle, the engine speed at the current gear, and the transmission system speed ratio parameters at each gear, and calculating the engine speed corresponding to each gear after the gear shift.

[0040] Here, the transmission control unit (TCU) obtains the current gear position of the vehicle from the transmission sensor and reads the transmission ratio parameters i under each gear position from the transmission control software. T =[i1,i2,i3,i4,i5,i6,…],i T Each element in represents the transmission ratio parameter in a gear; the engine speed N in the current gear is obtained from the engine controller through the CAN bus Act . Calculate the engine speed corresponding to each gear after shifting, using the following formula:

[0041]

[0042] Among them, N is the engine speed corresponding to each gear, in matrix form, N Act is the engine speed at the current gear, i Act is the transmission ratio parameter in the current gear, i T is the transmission system speed ratio parameter under each gear, in matrix form.

[0043] Step S2, obtaining the engine torque characteristics, and obtaining the maximum engine torque T corresponding to each gear position by interpolation calculation max =[T max1 ,T max2 ,T max3 ,T max4 ,T max5 ,T max6 ,…],T max Each element in represents the maximum engine torque corresponding to a gear; according to the maximum engine torque corresponding to each gear and the engine torque T under the current gear Eng The size relationship between them determines the engine torque corresponding to each gear after shifting.

[0044] Specifically, if T maxk ≤T Eng , then T k =T maxk ;

[0045] If T maxk >T Eng , then T k =T Eng ;

[0046] Among them, T maxkis the maximum engine torque corresponding to gear k, T Eng is the engine torque at the current gear, T k is the engine torque corresponding to gear k.

[0047] Step S3, obtaining the vehicle acceleration a in the current gear Act , according to the vehicle acceleration a in the current gear Act , Engine torque T at current gear Eng , tire radius R, transmission efficiency η at the current gear Act , vehicle weight m and wheel angular acceleration α, calculate the vehicle's current resistance f; according to the vehicle's current resistance f, the overall efficiency of the transmission system η T , the engine torque T corresponding to each gear, the transmission ratio parameter i under each gear T , calculate the vehicle acceleration a corresponding to each gear after shifting.

[0048] Here, the vehicle acceleration a in the current gear is obtained through the gearbox sensor Act The tire radius R and the overall efficiency of the transmission system η are read from the transmission control software. T =[η1,η2,η3,η4,η5,η6,…], and the vehicle weight m and wheel angular acceleration α are obtained through vehicle dynamics calculation.

[0049] Specifically, the current resistance of the vehicle is calculated using the following formula:

[0050]

[0051] Where f is the current resistance of the vehicle, T Eng is the engine torque at the current gear, i Act is the transmission ratio parameter under the current gear, R is the tire radius, η Act is the transmission efficiency at the current gear, m is the vehicle weight, a Act is the vehicle acceleration at the current gear, J is the transmission system moment of inertia converted to the wheels, and α is the wheel angular acceleration. Here, according to the tire radius R, the transmission system speed ratio parameter i at each gear T , the overall efficiency of the transmission system can be converted into J.

[0052] The following formula is used to calculate the vehicle acceleration corresponding to each gear position after shifting:

[0053]

[0054] Among them, a is the vehicle acceleration corresponding to each gear, in matrix form, T is the engine torque corresponding to each gear, in matrix form, T T is the transpose of T, i Tis the transmission ratio parameter under each gear, in matrix form, R is the tire radius, η T is the transmission ratio parameter under each gear, f is the current resistance of the vehicle, m is the vehicle weight, and J is the transmission rotational inertia converted to the wheels.

[0055] Step S4, obtaining the expected acceleration range under each throttle opening, determining the gear corresponding to the vehicle acceleration within the acceleration range among the vehicle accelerations corresponding to each gear, and forming a first gear set.

[0056] Here, the transmission controller reads the expected acceleration range [amin, amax] at each throttle opening that is calibrated and written from the transmission control software, where a min represents the lower limit of the acceleration range and a max represents the upper limit of the acceleration range. It determines one by one whether the vehicle acceleration corresponding to each gear is within [amin, amax], and obtains the gear that meets the expected acceleration, forming the first gear set.

[0057] Step S5, obtaining the expected engine speed range at each throttle opening, determining the gears in the first gear set that are within the engine speed range, and forming a second gear set.

[0058] Here, the transmission controller reads the expected engine speed range [Nmin, Nmax] at each throttle opening that is calibrated and written from the transmission control software, where N min represents the lower limit of the acceleration range and N max represents the upper limit of the acceleration range. It determines one by one whether each gear in the first gear set is within [Nmin, Nmax], and obtains the gear that meets the expected engine speed to form the second gear set.

[0059] Step S6, obtaining the engine universal characteristics, and determining the fuel consumption corresponding to each gear in the second gear set according to the engine speed corresponding to each gear, the engine torque corresponding to each gear, and the engine universal characteristics.

[0060] Here, the engine universal characteristics reflect the fuel consumption of the engine at different speeds and torques. According to the engine speed corresponding to each gear and the engine torque corresponding to each gear, the fuel consumption corresponding to each gear in the second gear set can be obtained in the engine universal characteristics.

[0061] Step S7, sorting the fuel consumption corresponding to each gear in the second gear set according to the fuel consumption, and selecting the gear corresponding to the lowest fuel consumption as the target gear for shifting.

[0062] The embodiment of the present application also provides a transmission controller for implementing the automatic transmission shifting method of the aforementioned embodiment.

[0063] The present application also provides an automatic transmission shifting system. Figure 2 The structural block diagram of the automatic transmission shifting system is shown in FIG. Figure 2 ,The system includes a transmission controller, a vehicle control unit VCU, and a transmission sensor;

[0064] The vehicle control unit sends the engine speed in the current gear, the engine torque in the current gear, and the engine torque characteristics to the transmission controller through the CAN bus; here, the engine controller sends the engine speed in the current gear, the engine torque in the current gear, the engine torque characteristics and other status information to the vehicle control unit.

[0065] The gearbox sensor sends the current gear of the vehicle and the vehicle acceleration in the current gear to the gearbox controller; here, the gearbox sensor includes a gear sensor and an acceleration sensor, the gear sensor is used to obtain the current gear of the vehicle and send it to the gearbox controller, and the acceleration sensor is used to obtain the vehicle acceleration in the current gear and send it to the gearbox controller.

[0066] The transmission controller is used to implement the automatic transmission shifting method of the above embodiment.

[0067] In summary, this application has the following technical effects:

[0068] The transmission controller of the present application obtains engine parameters from the vehicle control unit through the CAN bus, obtains the transmission status from the transmission sensor, reads calibration parameters from the transmission control software, and calculates the optimal target gear of the vehicle; the present application can reduce the calibration difficulty of the automatic transmission, reduce the workload of the calibration process, and improve the calibration quality of the transmission; calculate the power required by the vehicle in real time, and screen out the gear that meets the power requirements of the vehicle to meet the power requirements of the vehicle; select the gear with the lowest fuel consumption from all suitable gears to improve the economy of the vehicle.

[0069] The above are only various implementations of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A method for shifting a gearbox, characterized in that: include: Obtain the current gear of the vehicle, the engine speed at the current gear, and the transmission speed ratio parameters at each gear, and calculate the engine speed corresponding to each gear after the gear shift; Acquire the engine torque characteristics, and obtain the maximum engine torque corresponding to each gear position by interpolation calculation; determine the engine torque corresponding to each gear position after the gear shift according to the magnitude relationship between the maximum engine torque corresponding to each gear position and the engine torque at the current gear position; Obtaining the vehicle acceleration at the current gear, and calculating the vehicle current resistance according to the vehicle acceleration at the current gear, the engine torque at the current gear, the tire radius, the powertrain efficiency at the current gear, the vehicle weight, and the wheel angular acceleration; calculating the vehicle acceleration corresponding to each gear after the gear shift according to the vehicle current resistance, the overall powertrain efficiency, the engine torque corresponding to each gear, and the powertrain speed ratio parameters at each gear; Acquire the expected acceleration range under each throttle opening, determine the gear corresponding to the vehicle acceleration within the acceleration range among the vehicle accelerations corresponding to the gears, and form a first gear set; Obtaining the expected engine speed range at each throttle opening, determining the gears in the first gear set that are within the engine speed range, and forming a second gear set; Acquire the universal characteristics of the engine, and determine the fuel consumption corresponding to each gear in the second gear set according to the engine speed corresponding to each gear, the engine torque corresponding to each gear, and the universal characteristics of the engine; The fuel consumption corresponding to each gear in the second gear set is sorted according to the fuel consumption, and the gear corresponding to the lowest fuel consumption is selected as the target gear for shifting.

2. The method according to claim 1, characterized in that in, To calculate the engine speed corresponding to each gear after shifting, use the following formula: Among them, N is the engine speed corresponding to each gear, N Act is the engine speed at the current gear, i Act is the transmission ratio parameter in the current gear, i T It is the transmission ratio parameter under each gear.

3. The method according to claim 1, characterized in that in, Determining the engine torque corresponding to each gear position after the gear shift according to the magnitude relationship between the maximum engine torque corresponding to each gear position and the engine torque at the current gear position includes: If T maxk ≤T Eng , then T k =T maxk ; If T maxk >T Eng , then T k =T Eng ; Among them, T maxk is the maximum engine torque corresponding to gear k, T Wng is the engine torque at the current gear, T k is the engine torque corresponding to gear k.

4. The method according to claim 1, characterized in that in, The current resistance of the vehicle is calculated according to the vehicle acceleration at the current gear, the engine torque at the current gear, the tire radius, the powertrain efficiency at the current gear, the vehicle weight and the wheel angular acceleration, using the following formula: Where f is the current resistance of the vehicle, T Eng is the engine torque at the current gear, i Act is the transmission ratio parameter under the current gear, R is the tire radius, η Act is the transmission efficiency at the current gear, m is the vehicle weight, a Act is the vehicle acceleration in the current gear, J is the transmission system moment of inertia converted to the wheels, and α is the wheel angular acceleration.

5. The method according to claim 1, characterized in that in, According to the current resistance of the vehicle, the overall efficiency of the transmission system, the engine torque corresponding to each gear, and the transmission system speed ratio parameters under each gear, the vehicle acceleration corresponding to each gear after the gear shift is calculated using the following formula: Where a is the vehicle acceleration corresponding to each gear, T is the engine torque corresponding to each gear, and T T is the transpose of T, i T is the transmission ratio parameter under each gear, R is the tire radius, η T is the transmission ratio parameter under each gear, f is the current resistance of the vehicle, m is the vehicle weight, and J is the transmission rotational inertia converted to the wheels.

6. A gearbox controller, characterized in that: Used to implement the automatic transmission shifting method described in any one of claims 1-5.

7. An automatic transmission shifting system, characterized in that: Including transmission controller, vehicle control unit, transmission sensor; The vehicle control unit sends the engine speed at the current gear, the engine torque at the current gear, and the engine torque characteristics to the gearbox controller; The gearbox sensor sends the current gear position of the vehicle and the vehicle acceleration in the current gear position to the gearbox controller; The transmission controller is used to implement the automatic transmission shifting method according to any one of claims 1 to 5.

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