An automatic transmission shifting method

Abstract

This application relates to an automatic transmission shifting method. The transmission controller obtains engine parameters from the vehicle control unit via the CAN bus, acquires transmission status from transmission sensors, and reads calibration parameters from the transmission control software to calculate the optimal target gear for the vehicle. This application can reduce the calibration difficulty of automatic transmissions, reduce the workload of the calibration process, and improve the calibration quality of transmissions. It can calculate the power required by the vehicle in real time and select the gear that meets the power requirements of the vehicle to satisfy the power requirements of the vehicle. It can also select the gear with the lowest fuel consumption from all suitable gears to improve vehicle economy.

Description

Technical Field

[0001] This application relates to the field of gearbox shifting, and more specifically, to a method for shifting gears in an automatic gearbox. Background Technology

[0002] Currently, automatic transmissions select their target gear based on engine speed. Once the engine speed reaches the set shift point, the automatic transmission enters shift mode, calculates the engine speed after the shift, and selects the target gear accordingly. Furthermore, external conditions such as vehicle weight, slope, and altitude also affect gear shifting. The automatic transmission compensates for changes in external conditions by adjusting the set shift points to ensure sufficient power after shifting. During automatic transmission calibration, the shift points need to be calibrated based on engine characteristics, and compensation calibration is also required for different vehicle weights, slopes, altitudes, and other external conditions.

[0003] With the increasing prevalence of automatic transmission vehicles, users have higher demands for their shifting strategies. They require automatic transmissions to provide both the power needed for challenging road conditions, such as mountainous terrain, and fuel efficiency for smoother driving on good roads, thus saving fuel. OEMs also use the Vehicle Control Unit (VCU) to adjust engine characteristics based on actual driving conditions to achieve fuel savings. However, these engine adjustments affect the automatic transmission's shifting, potentially leading to insufficient power after shifting. Summary of the Invention

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

[0005] Firstly, an automatic transmission shifting method is provided, comprising:

[0006] Obtain the vehicle's current gear, engine speed in the current gear, and transmission ratio parameters for each gear, and calculate the engine speed corresponding to each gear after shifting.

[0007] The engine torque characteristics are obtained, and the maximum engine torque corresponding to each gear is calculated by interpolation. Based on the relationship between the maximum engine torque corresponding to each gear and the engine torque in the current gear, the engine torque corresponding to each gear after shifting is determined.

[0008] Obtain the vehicle acceleration in the current gear. Calculate the current vehicle resistance based on the current vehicle acceleration, engine torque, tire radius, transmission efficiency, vehicle weight, and wheel angular acceleration. Calculate the vehicle acceleration corresponding to each gear after shifting based on the current vehicle resistance, overall transmission efficiency, engine torque corresponding to each gear, and transmission ratio parameters for each gear.

[0009] Obtain the desired acceleration range at each throttle opening, determine the gear corresponding to the vehicle acceleration within the acceleration range for each gear, and form the first gear set;

[0010] Obtain the desired engine speed range at each throttle opening, determine the gears in the first gear set that are within the engine speed range, and form the second gear set;

[0011] Obtain the universal characteristics of the engine, and determine the fuel consumption of each gear in the second gear set based on the engine speed, engine torque, and universal characteristics of each gear.

[0012] The fuel consumption of each gear in the second gear set is sorted according to its value from highest to lowest, and the gear with the lowest fuel consumption is selected as the target gear for shifting.

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

[0014]

[0015] Where N is the engine speed corresponding to each gear, N Act i represents the engine speed in the current gear. Act i represents the transmission ratio parameter for the current gear. T These are the transmission ratio parameters for each gear.

[0016] In one embodiment, determining the engine torque corresponding to each gear after shifting, based on the relationship between the maximum engine torque corresponding to each gear and the engine torque in the current gear, 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 maxkT represents the maximum engine torque corresponding to gear k. Eng T represents the engine torque in the current gear. k This represents the engine torque corresponding to gear k.

[0020] In one embodiment, the current vehicle resistance is calculated based on the vehicle acceleration in the current gear, the engine torque in the current gear, the tire radius, the transmission efficiency in 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, and T Eng i represents the engine torque in the current gear. Act Here are the transmission ratio parameters for the current gear, R is the tire radius, and η is the torque coefficient. Act The efficiency of the transmission system in the current gear, m is the vehicle weight, and a Act J is the vehicle acceleration in the current gear, J is the transmission inertia referred to the wheels, and α is the wheel angular acceleration.

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

[0024]

[0025] Where 'a' represents the vehicle acceleration corresponding to each gear, and 'T' represents the engine torque corresponding to each gear. T Let i be the transpose of T. T Here are the transmission ratio parameters for each gear, R is the tire radius, and η is the transmission ratio parameter for each gear. T Here are the transmission ratio parameters for each gear, f is the current resistance of the vehicle, m is the vehicle weight, and J is the transmission inertia referred to the wheels.

[0026] Secondly, a transmission controller is provided for implementing the above-mentioned automatic transmission shifting method.

[0027] Thirdly, an automatic transmission shifting system is provided, including a transmission controller, a vehicle control unit, and transmission sensors;

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

[0029] The transmission sensor sends the vehicle's current gear and the vehicle's acceleration in the current gear to the transmission controller;

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

[0031] Compared with the prior art, this application has the following beneficial effects: The automatic transmission shifting method of this application obtains engine parameters from the vehicle control unit via the CAN bus, obtains the transmission status from the transmission sensors, and reads calibration parameters from the transmission control software to calculate the optimal target gear for the vehicle; this 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; it can calculate the power required by the vehicle in real time and select the gear that meets the power requirements of the vehicle to meet the power requirements of the vehicle; and it can select the gear with the lowest fuel consumption among all suitable gears to improve the vehicle's economy. Attached Figure Description

[0032] This application can be better understood by referring to the description given below in conjunction with the accompanying drawings, which, together with the detailed description below, are incorporated in and form part of this specification. In the drawings:

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

[0034] Figure 2 A structural block diagram of an automatic transmission shifting system is shown. Detailed Implementation

[0035] Exemplary embodiments of the present application will be described below with reference to the accompanying drawings. For clarity and brevity, not all features of the actual embodiments are described in the specification. However, it should be understood that many embodiment-specific decisions can be made in the development of any such actual embodiment to achieve the developer’s specific objectives, and these decisions may vary as the embodiments differ.

[0036] It should also be noted that, in order to avoid obscuring this application with unnecessary details, only the device structure closely related to the solution according to this application is shown in the accompanying drawings, while other details that are not closely related to this application are omitted.

[0037] It should be understood that this application is not limited to the described embodiments by virtue of the following description with reference to the accompanying drawings. In this document, embodiments may be combined with each other, features may be substituted or borrowed between different embodiments, and one or more features may be omitted in one embodiment, where feasible.

[0038] This application provides an automatic transmission shifting method. Figure 1 A flowchart of an automatic transmission shifting method is shown; see [link / reference]. Figure 1 The methods include:

[0039] Step S1: Obtain the vehicle's current gear, the engine speed in the current gear, and the transmission ratio parameters in each gear, and calculate the engine speed corresponding to each gear after shifting.

[0040] Here, the Transmission Control Unit (TCU) obtains the vehicle's current gear from the transmission sensors and reads the transmission ratio parameters i for each gear from the transmission control software. T =[i1,i2,i3,i4,i5,i6,…],i T Each element in the table represents the transmission ratio parameter for a given gear; the engine speed N for the current gear is obtained from the engine controller via the CAN bus. Act Calculate the engine speed corresponding to each gear after shifting using the following formula:

[0041]

[0042] Where N represents the engine speed corresponding to each gear, and is in matrix form, N Act i represents the engine speed in the current gear. Act i represents the transmission ratio parameter for the current gear. T These are the transmission ratio parameters for each gear, presented in matrix form.

[0043] Step S2: Obtain the engine torque characteristics and calculate the maximum engine torque T corresponding to each gear through interpolation. max =[T max1 ,T max2 ,T max3 ,T max4 ,T max5 ,T max6 ,…],T max Each element in the table represents the maximum engine torque corresponding to a gear; based on the maximum engine torque corresponding to each gear and the engine torque T in the current gear... Eng The magnitude relationship between the gears 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 maxkT represents the maximum engine torque corresponding to gear k. Eng T represents the engine torque in the current gear. k This represents the engine torque corresponding to gear k.

[0047] Step S3, obtain the vehicle acceleration a in the current gear. Act Based on the vehicle acceleration a in the current gear Act Engine torque T in the current gear Eng Tire radius R, transmission efficiency η in the current gear Act Given the vehicle weight m and wheel angular acceleration α, calculate the vehicle's current resistance f; based on the vehicle's current resistance f and the overall efficiency η of the transmission system... T Engine torque T for each gear, and transmission ratio i for each gear. T Calculate the vehicle acceleration 'a' corresponding to each gear after shifting gears.

[0048] Here, the vehicle acceleration 'a' in the current gear is obtained through the transmission sensor. Act The tire radius R and overall transmission efficiency 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 calculations.

[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, and T Eng i represents the engine torque in the current gear. Act Here are the transmission ratio parameters for the current gear, R is the tire radius, and η is the torque coefficient. Act The efficiency of the transmission system in the current gear, m is the vehicle weight, and a Act Let J be the vehicle acceleration in the current gear, J be the transmission system moment of inertia referred to the wheels, and α be the wheel angular acceleration. Here, based on the tire radius R and the transmission system speed ratio parameter i in each gear... T The overall efficiency of the transmission system can be calculated in J.

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

[0053]

[0054] Where 'a' represents the vehicle acceleration corresponding to each gear, in matrix form, and 'T' represents the engine torque corresponding to each gear, in matrix form. T Let i be the transpose of T. TThe transmission ratio parameters for each gear are in matrix form, where R is the tire radius and η is the torque coefficient. T Here are the transmission ratio parameters for each gear, f is the current resistance of the vehicle, m is the vehicle weight, and J is the transmission inertia referred to the wheels.

[0055] Step S4: Obtain the desired acceleration range at each throttle opening, determine the gear corresponding to the vehicle acceleration within the acceleration range for each gear, and form the first gear set.

[0056] Here, the transmission controller reads the expected acceleration range [amin, amax] for each throttle opening from the transmission control software, where amin represents the lower limit of the acceleration range and amax represents the upper limit of the acceleration range. It then checks whether the vehicle acceleration corresponding to each gear is within [amin, amax] to obtain the gears that meet the expected acceleration, thus forming the first gear set.

[0057] Step S5: Obtain the desired engine speed range at each throttle opening, determine the gears in the first gear set that are within the engine speed range, and form the second gear set.

[0058] Here, the transmission controller reads the expected engine speed range [Nmin, Nmax] for each throttle opening from the transmission control software, where Nmin represents the lower limit of the acceleration range and Nmax represents the upper limit of the acceleration range. It then checks whether each gear in the first gear set is within [Nmin, Nmax] to obtain the gears that meet the expected engine speed, thus forming the second gear set.

[0059] Step S6: Obtain the universal characteristics of the engine. Based on the engine speed, engine torque, and universal characteristics of each gear, determine the fuel consumption of each gear in the second gear set.

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

[0061] Step S7: Sort the fuel consumption of each gear in the second gear set according to the fuel consumption level, and select the gear with the lowest fuel consumption as the target gear for shifting.

[0062] This application also provides a transmission controller for implementing the automatic transmission shifting method of the foregoing embodiments.

[0063] This application also provides an automatic transmission shifting system. Figure 2 A block diagram of the automatic transmission shifting system is shown. See [link / reference] Figure 2 The system includes a transmission controller, a vehicle control unit (VCU), and transmission sensors.

[0064] The vehicle control unit sends the engine speed, engine torque, and engine torque characteristics of the current gear to the transmission controller via the CAN bus; here, the engine controller sends the status information such as the engine speed, engine torque, and engine torque characteristics of the current gear to the vehicle control unit.

[0065] The transmission sensor sends the vehicle's current gear and the vehicle's acceleration in the current gear to the transmission controller. Here, the transmission sensor includes a gear position sensor and an acceleration sensor. The gear position sensor is used to obtain the vehicle's current gear and send it to the transmission controller, and the acceleration sensor is used to obtain the vehicle's acceleration in the current gear and send it to the transmission controller.

[0066] The transmission controller is used to implement the automatic transmission shifting method described in the above embodiments.

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

[0068] The transmission controller of this application obtains engine parameters from the vehicle control unit via the CAN bus, acquires transmission status from transmission sensors, reads calibration parameters from the transmission control software, and calculates the optimal target gear for the vehicle. This application can reduce the calibration difficulty of automatic transmissions, reduce the workload of the calibration process, and improve the calibration quality of transmissions; it can calculate the power required by the vehicle in real time and select the gear that meets the power requirements of the vehicle to satisfy the vehicle's power needs; and it can select the gear with the lowest fuel consumption from all suitable gears to improve vehicle economy.

[0069] The above descriptions are merely various embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. An automatic transmission shifting method, characterized in that, include: Obtain the vehicle's current gear, engine speed in the current gear, and transmission ratio parameters for each gear, and calculate the engine speed corresponding to each gear after shifting. The engine torque characteristics are obtained, and the maximum engine torque corresponding to each gear is calculated by interpolation. Based on the relationship between the maximum engine torque corresponding to each gear and the engine torque in the current gear, the engine torque corresponding to each gear after shifting is determined. Obtain the vehicle acceleration in the current gear, and calculate the current vehicle resistance based on the vehicle acceleration in the current gear, the engine torque in the current gear, the tire radius, the transmission efficiency in the current gear, the vehicle weight, and the wheel angular acceleration; calculate the vehicle acceleration corresponding to each gear after shifting based on the current vehicle resistance, the overall transmission efficiency, the engine torque corresponding to each gear, and the transmission ratio parameters of each gear. Obtain the desired acceleration range at each throttle opening, determine the gear corresponding to the vehicle acceleration within the acceleration range for each gear, and form a first gear set; Obtain the desired engine speed range at each throttle opening, determine the gears in the first gear set that are within the engine speed range, and form a second gear set; Obtain the universal characteristics of the engine, and determine the fuel consumption corresponding to each gear in the second gear set based on the engine speed corresponding to each gear, the engine torque corresponding to each gear, and the universal characteristics of the engine. The fuel consumption of each gear in the second gear set is sorted according to its value from highest to lowest, and the gear with the lowest fuel consumption is selected as the target gear for shifting.

2. The method as described in claim 1, characterized in that, in, The engine speed corresponding to each gear after shifting is calculated using the following formula: in, These are the engine speeds corresponding to each gear. This refers to the engine speed in the current gear. The transmission ratio parameter for the current gear. These are the transmission ratio parameters for each gear.

3. The method as described in claim 1, characterized in that, in, Based on the relationship between the maximum engine torque corresponding to each gear and the engine torque in the current gear, the engine torque corresponding to each gear after shifting is determined, including: like ,but ; like ,but ; in, For gear The corresponding maximum engine torque, This refers to the engine torque in the current gear. For gear The corresponding engine torque.

4. The method as described in claim 1, characterized in that, in, The current vehicle resistance is calculated based on the vehicle acceleration in the current gear, the engine torque in the current gear, the tire radius, the transmission efficiency in the current gear, the vehicle weight, and the wheel angular acceleration, using the following formula: in, The current resistance of the vehicle, This refers to the engine torque in the current gear. The transmission ratio parameter for the current gear. For the tire radius, The efficiency of the transmission system in the current gear. For vehicle weight, The acceleration of the vehicle in the current gear. To calculate the moment of inertia of the transmission system converted to the wheels, This refers to the wheel's angular acceleration.

5. The method as described in claim 1, characterized in that, in, Based on the vehicle's current resistance, overall transmission efficiency, engine torque corresponding to each gear, and transmission ratio parameters for each gear, the vehicle acceleration corresponding to each gear after shifting is calculated using the following formula: in, The vehicle acceleration corresponding to each gear. This refers to the engine torque corresponding to each gear. for transpose, These are the transmission ratio parameters for each gear. For the tire radius, These are the transmission ratio parameters for each gear. The current resistance of the vehicle, For vehicle weight, This is the moment of inertia of the transmission system converted to the wheels.

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

7. An automatic transmission shifting system, characterized in that, This includes the transmission controller, vehicle control unit, and transmission sensors; The vehicle control unit sends the engine speed, engine torque, and engine torque characteristics of the current gear to the transmission controller. The transmission sensor sends the vehicle's current gear and the vehicle's acceleration in the current gear to the transmission controller; The transmission controller is used to implement the automatic transmission shifting method according to any one of claims 1-5.

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