RU2794446C1 - Intelligent four-wheel drive control method and system, as well as the vehicle - Google Patents

Abstract

FIELD: vehicles.

SUBSTANCE: in the all-wheel drive intelligent control method, vehicle state information is obtained, including the speed of the front and rear wheels of the vehicle; an estimated output torque based on the vehicle state information is calculated; the vehicle friction disc temperature based on the front wheel speed, the rear wheel speed, and the estimated output torque is calculated. The calculated output torque is corrected according to the calculated friction disc temperature to obtain the actual output torque, and the friction clutch is controlled to generate the actual output torque.

EFFECT: improved reliability of the temperature measurement of the friction disc.

11 cl, 10 dwg

Description

[0001] The present application claims priority according to PRC Patent Application No. 201911053493.4 "Full Drive Intelligent Control Method and System and Vehicle" filed on October 31, 2019 by China State National Intellectual Property Administration, which is hereby incorporated by reference in its entirety. .

Technical field

[0002] The present invention relates to vehicles, and in particular to a method and system for intelligent control of a four-wheel drive and a vehicle.

State of the art

[0003] When using the vehicle's all-wheel drive system, the power of the vehicle's engine can be transferred, depending on the condition of the road and the vehicle, to any desired wheel to increase the traction of all wheels and improve the flotation, maneuverability and acceleration of the vehicle. The intelligent all-wheel drive system can automatically adjust the all-wheel drive mode to realize all-wheel drive, while providing convenience to the driver.

[0004] In a conventional intelligent four-wheel drive system, it is generally necessary to control the temperature of the friction disc in order to prevent ablative destruction or burning of the friction disc, or to prevent early failure of the four-wheel drive system. In the conventional temperature control method, the temperature of the oil at the location of the friction disc is measured and controlled using a temperature sensor, and the temperature of the friction disc is determined from it.

[0005] However, with this temperature control method, since the temperature of the controlled friction disc is determined from the oil temperature, there are problems of control inertia and insufficient reliability. Due to the lack of reliability of readings relative to the temperature of the friction disc, there is no way to correct the output torque based on the temperature of the friction disc.

The essence of the invention

[0006] In view of the foregoing, it is an object of the present invention to provide a method and system for intelligent control of an all-wheel drive and a vehicle to solve the problem of friction disc temperature control inertia, insufficient reliability of friction disc temperature measurement, and inability to correct output torque.

[0007] To achieve these goals, the following technical solutions according to the present invention are proposed.

[0008] A method for intelligent control of a four-wheel drive is proposed, including:

[0009] obtaining information about the state of the vehicle, which includes the speed of the front wheels and the speed of the rear wheels of the vehicle;

[0010] calculating an estimated output torque based on the vehicle state information;

[0011] calculating the temperature of the friction disc of the vehicle based on the speed of the front wheels, the speed of the rear wheels and the estimated output torque;

[0012] correcting the estimated output torque based on the temperature of the friction disc to obtain the actual output torque; And

[0013] controlling the friction clutch to generate the actual output torque.

[0014] In another embodiment of the present invention, the step of calculating the temperature of the vehicle friction disc based on the speed of the front wheels, the speed of the rear wheels and the estimated output torque includes:

[0015] calculating a front and rear wheel speed difference based on the front wheel speed and the rear wheel speed; And

[0016] calculating the temperature of the friction disc of the vehicle based on the difference between the speeds of rotation of the front and rear wheels and the estimated output torque.

[0017] In yet another embodiment of the present invention, the step of calculating the temperature of the vehicle friction disc based on the difference between the speeds of rotation of the front and rear wheels and the estimated output torque includes:

[0018] calculating the generation of heat in the friction disc of the vehicle based on the difference between the speeds of rotation of the front and rear wheels and the estimated output torque;

[0019] obtaining the previous value of the oil temperature at the location of the friction disc;

[0020] calculating friction disc heat dissipation based on the previous temperature value; And

[0021] calculating the temperature of the friction disc based on heat generation in the friction disc and heat dissipation by the friction disc.

[0022] In yet another embodiment of the present invention, the vehicle state information further comprises the vehicle speed and the ambient temperature, and after performing the step of calculating the friction disc temperature based on heat generation in the friction disc and heat dissipation by the friction disc, the method further includes:

[0023] calculating the current oil temperature at the location of the friction disc based on the heat dissipation of the friction disc, vehicle speed, and ambient temperature; And

[0024] transmitting an overheating protection signal to the vehicle when the friction disc temperature satisfies the first predetermined condition and/or when the current oil temperature satisfies the second predetermined condition.

[0025] In another embodiment of the present invention, the step of correcting the calculated output torque according to the temperature of the friction disc to obtain the actual output torque includes:

[0026] calculating a temperature correction factor based on the temperature of the friction disc;

[0027] deriving a temperature-compensated output torque based on the estimated output torque and the temperature correction factor;

[0028] calculating the moment of resistance based on the difference between the speeds of rotation of the front and rear wheels; And

[0029] deriving the actual output torque based on the drag torque and the temperature compensated output torque.

[0030] The advantages of the all-wheel drive intelligent control method according to the present invention compared to known technical solutions are as follows.

[0031] In the all-wheel drive intelligent control method according to the embodiments of the present invention, the estimated output torque can be calculated for the vehicle based on the received vehicle state information; then, the temperature of the friction disc of the vehicle can be calculated based on the speed of the front wheels, the speed of the rear wheels, and the estimated output torque; and the actual output torque can be obtained by correcting the estimated output torque according to the temperature of the friction disc, and the friction clutch of the vehicle is controlled to generate the actual output torque. In the all-wheel drive intelligent control method according to the embodiments of the present invention, the friction disc temperature is obtained directly from the real-time vehicle state information, and thus has a higher accuracy; in addition, the calculated output torque is corrected using the temperature of the friction disk, which improves the accuracy of the output torque control, thereby improving the vehicle's maneuverability and the vehicle's ability to get out of a tight position, and reducing the possibility of ablative failure of the friction disk.

[0032] Yet another object of the present invention is to provide a four-wheel drive intelligent control system for solving the problem of friction disc temperature control inertia, insufficient reliability of friction disc temperature measurement, and failure to correct output torque.

[0033] To achieve these goals, the following technical solution according to the present invention is proposed.

[0034] A four-wheel drive intelligent control system is provided, comprising a receiving module, a torque calculation module, a temperature calculation module, and a torque control module.

[0035] The receiving module is connected to the torque calculation module and the temperature calculation module, and the torque calculation module is connected to the temperature calculation module and the torque control module.

[0036] The receiving module is configured to obtain vehicle state information, wherein the vehicle state information includes front wheel speed and rear wheel speed.

[0037] The torque calculation module is configured to calculate the estimated output torque based on the vehicle state information.

[0038] The temperature calculation module is configured to calculate the temperature of the vehicle friction disc based on the front wheel speed, the rear wheel speed, and the calculated output torque.

[0039] The torque calculation module is further configured to correct the estimated output torque based on the temperature of the friction disc to obtain the actual output torque.

[0040] The torque control module is configured to control the friction clutch to generate the actual torque output.

[0041] In yet another embodiment of the present invention, the temperature calculation module is configured to:

[0042] calculating a front and rear wheel speed difference based on the front wheel speed and the rear wheel speed, and calculating a heat generation in the vehicle friction disc based on the front and rear wheel speed difference and the calculated output torque; And

[0043] obtaining the historical value of the oil temperature at the position of the friction disk, calculating the heat dissipation of the friction disk based on the previous temperature value, and calculating the temperature of the friction disk based on the generation of heat in the friction disk and the heat dissipation of the friction disk.

[0044] In yet another embodiment of the present invention, the vehicle state information further comprises a vehicle speed and an ambient temperature, and the system further comprises an overheat protection module.

[0045] The overheat protection module is associated with the temperature calculation module.

[0046] The temperature calculation module is further configured to calculate, based on the friction disc heat dissipation, the vehicle speed and the ambient temperature, the current oil temperature at the location of the friction disc.

[0047] The overheat protection module is configured to send an overheat protection signal to the vehicle when the friction disc temperature satisfies the first predetermined condition and/or when the current oil temperature satisfies the second predetermined condition.

[0048] In yet another embodiment of the present invention, the torque calculation module is further configured to:

[0049] calculating a temperature correction factor based on the temperature of the friction disc; obtaining a temperature-compensated output torque based on the calculated output torque and the temperature correction factor; calculating a drag torque based on a speed difference between the front and rear wheels; and obtaining an actual output torque based on the drag torque and a temperature-compensated output torque.

[0050] The advantages of the intelligent four-wheel drive control system over conventional solutions are the same as the advantages of the intelligent four-wheel drive control method, and therefore are not repeated here.

[0051] Yet another object of the present invention is to provide a vehicle for solving the problems of friction disc temperature control inertia, insufficient reliability of the obtained friction disc temperatures, and inability to correct the output torque.

[0052] To achieve this goal, the following technical solution was applied.

[0053] Proposed is a vehicle containing the above all-wheel drive intelligent control system.

[0054] The advantages of such a vehicle over conventional technical solutions are the same as those of an intelligent four-wheel drive control system, and therefore are not repeated here.

[0055] The technical solutions according to the present invention are briefly described above. For a better understanding of the technical means and practical use of the present invention, as well as for a better understanding of the above and other objects, features and advantages of the present invention, specific embodiments of the present invention are disclosed below.

Brief description of the drawings

[0056] In order to more clearly illustrate embodiments of the present invention or prior art, the following are the accompanying drawings necessary to describe embodiments of the present invention. Obviously, the drawings, which form part of the present description, are intended to give a better understanding of the present invention. These exemplary embodiments of the present invention and the description are intended to explain the present invention, and do not limit its scope. On the drawings:

[0057] in FIG. 1 is a flowchart of a four-wheel drive intelligent control method according to an embodiment of the present invention;

[0058] in FIG. 2 is a flowchart of a four-wheel drive intelligent control method according to another embodiment of the present invention;

[0059] in FIG. 3 is a block diagram of a four-wheel drive intelligent control system according to an embodiment of the present invention;

[0060] in FIG. 4 schematically shows the control process of the four-wheel drive intelligent control system according to an embodiment of the present invention;

[0061] FIG. 5 is a schematic diagram showing a calculation model for calculating a friction disc temperature included in a temperature calculation module according to an embodiment of the present invention;

[0062] in FIG. 6 is a schematic diagram showing a calculation model in a torque calculation module according to another embodiment of the present invention;

[0063] in FIG. 7 is a schematic diagram showing a calculation model for calculating the current oil temperature included in a temperature calculation module according to another embodiment of the present invention;

[0064] in FIG. 8 is a schematic diagram showing a computational model in an overtemperature protection module according to another embodiment of the present invention;

[0065] in FIG. 9 schematically shows a computing device configured to perform the method according to the present invention; And

[0066] in FIG. 10 schematically shows a storage device for storing or transferring program code for implementing a method according to an embodiment of the present invention.

[0067] The following symbols are used in the drawings:

[0068] 301: Receiving module

3011: Vehicle status information

302: Torque calculation module

3021: Output torque calculation

3022: Modulus

3023: Temperature compensated output torque

3024: Actual output torque

303: Temperature calculation module

3031: Speed difference between front and rear wheels

3032: Heat generation in the friction disc

3033: Friction disc heat dissipation

3034: Friction disc temperature

3035: Heat absorbed by oil

3036: Heat dissipated by oil

3037: Current oil temperature

304: Torque control module

305: Thermal protection module.

Detailed description

[0069] For a clearer understanding of the objectives, technical solutions and advantages of the present invention, the following technical solutions of the embodiments of the present invention are described in detail with reference to the accompanying drawings. Obviously, the embodiments of the present invention described below are only a part and not all of the embodiments of the present invention. Any other embodiments of the present invention, formulated by experts on the basis of the options discussed in this document, without the application of creative efforts, should be considered as being within the scope of the present invention.

[0070] It should be noted that the embodiments of the present invention and their features can be combined with each other, as long as they do not conflict with each other.

[0071] Below, the present invention is described in detail with reference to the accompanying drawings and embodiments of the present invention.

[0072] Embodiment 1 of the present invention

[0073] FIG. 1 shows a flowchart of a four-wheel drive intelligent control method according to one embodiment of the present invention.

[0074] The all-wheel drive intelligent control method proposed in this embodiment of the present invention is applicable to a vehicle. The method may include steps 101-105.

[0075] In step 101, vehicle state information is obtained, wherein the vehicle state information includes a front wheel speed and a rear wheel speed of the vehicle.

[0076] The all-wheel drive intelligent control method proposed in these embodiments of the present invention is mainly applicable to a vehicle's intelligent all-wheel drive control system. The four-wheel drive intelligent control system contains an electronic control unit and an electronic torque control manager. The electronic torque manager contains a group of friction clutches. The electronic torque control manager can control in real time the torque transmitted from the friction clutch in response to the electronic control signal sent from the electronic control unit. The electronic control unit contains a plurality of modules to automatically control the four-wheel drive system based on various road conditions and vehicle status information, so as not only to ensure proper flotation, maneuverability, acceleration of the vehicle, but also to eliminate phenomena such as braking skid and vibration. , striking a balance between driver experience and all-wheel drive performance.

[0077] More specifically, in another embodiment of the present invention, the vehicle state information comprises real-time vehicle state information and basic vehicle information. Real-time status information may include: vehicle speed, wheel speed, steering angle, gear shift position, engine torque, ambient temperature, stop time, and the like. Basic information may include: transmission ratios, rolling radius, wheelbase, steering ratio, etc.

[0078] In step 102, an estimated output torque is calculated based on the vehicle state information.

[0079] In yet another embodiment of the present invention, based on step 101, calculate the estimated output torque of the friction clutch based on the obtained information about the state of the vehicle, such as wheel speed, engine torque, shift position in the gearbox, and steering wheel angle.

[0080] Further, an embodiment of the present invention includes step 103.

[0081] In step 103, the vehicle friction disc temperature is calculated based on the front wheel speed, the rear wheel speed, and the estimated output torque.

[0082] In another embodiment of the present invention, the speed of the front wheels and the speed of the rear wheels mainly determine the difference in the speeds of rotation of the front and rear wheels of the vehicle, and this difference in the speeds of rotation of the front and rear wheels determines the downforce and the displacement of the friction disc in the friction muff. The generation of heat in the friction disc is mainly caused by friction. When the speed difference between the front and rear wheels is 0, the temperature of the friction disc is mainly due to the generation of heat that occurs when the friction disc stirs the oil. By combining the calculated output torque with the speed of rotation of the front and rear wheels, the temperature of the friction disc can be calculated more reliably and accurately.

[0083] In step 104, the actual output torque is obtained by correcting the estimated output torque based on the temperature of the friction disc.

[0084] In practical application, the coefficient of friction of the friction disc is affected by the temperature of the friction disc, with different temperatures corresponding to different coefficients of friction. The coefficient of friction affects the accuracy of determining the output torque. In yet another embodiment of the present invention, the calculated output torque is corrected according to the temperature of the friction disc. The actual output torque can be adjusted according to the temperature of the friction disk, so as to avoid excessive output torque when the temperature of the friction disk is high, resulting in improved control accuracy of the actual output torque, reduced the possibility of ablative failure of the friction disk, and improved vehicle maneuverability and vehicle capability. means to get out of difficult situations.

[0085] At step 105, the friction clutch of the vehicle is controlled to generate the actual output torque.

[0086] In this embodiment of the present invention, based on step 104, the torque control module in the electronic control unit obtains, based on the calculated actual output torque, the current required to operate the friction clutch; and controls, using this current, the operation of the friction clutch to provide the actual output torque. Thus, the likelihood of ablative failure of the friction disc is reduced while meeting the actual needs of the vehicle.

[0087] As a result, the all-wheel drive intelligent control method according to this embodiment of the present invention has at least the following advantages.

[0088] When using the all-wheel drive intelligent control method described in this embodiment of the present invention, the estimated output torque of the vehicle can be calculated based on the acquired vehicle state information; then, the temperature of the friction disc of the vehicle can be calculated based on the speed of the front wheels, the speed of the rear wheels, and the estimated output torque; and the actual output torque is obtained by correcting the estimated output torque based on the temperature of the friction disc, and the vehicle friction clutch is controlled to provide the actual output torque. In this four-wheel drive intelligent control method disclosed in the embodiments of the present invention, the temperature of the friction disc is obtained directly in real time based on the state information of the vehicle, and thus has a higher accuracy; in addition, the calculated output torque is corrected according to the temperature of the friction disc, which improves the accuracy of the output torque control, thus improving the vehicle's maneuverability and the vehicle's ability to get out of difficult situations, and the possibility of ablative failure of the friction disc is reduced.

[0089] Embodiment 2 of the present invention

[0090] FIG. 2 shows a flowchart of a four-wheel drive intelligent control method according to another embodiment of the present invention.

[0091] The all-wheel drive intelligent control method disclosed in this embodiment of the present invention is applicable to a vehicle. The method may include steps 201-214.

[0092] In step 201, vehicle state information is obtained, wherein the vehicle state information includes a front wheel speed and a rear wheel speed of the vehicle.

[0093] To understand step 201, reference can be made to step 101 of Embodiment 1 of the present invention.

[0094] In step 202, an estimated output torque is calculated based on the vehicle state information.

[0095] To understand step 202, you can refer to step 102 of option 1 implementation of the present invention.

[0096] In step 203, a difference between the front and rear wheel speeds is calculated based on the front wheel speed and the rear wheel speed.

[0097] The difference between the speeds of rotation of the front and rear wheels is the difference between the average value of the speed of the front wheels and the average value of the speed of the rear wheels. The speed difference between the front and rear wheels is not only the main factor in the heat generation of the friction disc, but also the main parameter in calculating the moment of resistance. The resistive torque is a fraction of the actual output torque. In this embodiment of the present invention, the difference between the speeds of rotation of the front and rear wheels and the moment of resistance are introduced in order to improve the accuracy in calculating the temperature of the friction disc and improve the accuracy of calculating the actual output torque.

[0098] In step 204, based on the difference between the speeds of rotation of the front and rear wheels and the estimated output torque, heat generation in the friction disc is calculated.

[0099] In this embodiment of the present invention, the speed difference between the front and rear wheels and the calculated output torque are mainly used to calculate the work done by the sliding friction in the friction disc. The work done by the sliding friction is the main source of temperature increase in the friction disc, and the heat generation in the friction disc can be calculated from the work done by the sliding friction.

[0100] In step 205, the previous temperature of the oil in which the friction disc is located is obtained.

[0101] In this embodiment of the present invention, after the heat generation in the friction disc is calculated in step 204, the heat dissipation of the friction disc is calculated. In practice, the heat of the friction disc is dissipated by the oil in which the friction disc is located.

[0102] In step 206, the heat dissipation of the friction disc is calculated based on the previous temperature.

[0103] In this embodiment of the present invention, the real-time oil temperature is obtained based on the friction disc heat dissipation, and the friction disc heat dissipation is calculated using the previous oil temperature.

[0104] In step 207, the friction disc temperature is calculated based on heat generation in the friction disc and heat dissipation by the friction disc.

[0105] In this embodiment of the present invention, the friction disc temperature variation can be calculated by subtracting the friction disc heat dissipation from the friction disc heat generation, and then the variation can be integrated to obtain the friction disc temperature.

[0106] This friction disc temperature calculation method according to this embodiment of the present invention takes into account the influence of the difference between the speeds of rotation of the front and rear wheels on the friction disc temperature, and it improves the calculation accuracy of the friction disc temperature, which leads to a reduction in cost, an improvement in performance in real life. time and simplification compared to the indirect calculation of the temperature of the friction disc by means of a temperature sensor.

[0107] In step 208, the current temperature of the oil in which the friction disc is placed is calculated based on heat dissipation by the friction disc, vehicle speed, and ambient temperature.

[0108] In this embodiment of the present invention, the current temperature of the oil in which the friction disc is placed can be accurately calculated based on the heat dissipation of the friction disc in combination with the vehicle speed and the ambient temperature. The dissipation of heat by the friction disc is the main source of heat for the oil. In addition, vehicle speed and ambient temperature have a certain effect on the heat dissipation of the oil. By using the method for calculating the current oil temperature according to this embodiment of the present invention, the calculation becomes simpler and cheaper while ensuring the accuracy of calculating the current oil temperature.

[0109] In step 209, an overheat protection signal is transmitted to the vehicle when the friction disc temperature satisfies the first predetermined condition and/or when the current oil temperature satisfies the second predetermined condition.

[0110] In this embodiment of the present invention, overheating protection can be applied to the vehicle if the friction disc temperature becomes excessively high or the current oil temperature becomes excessively high, that is, when the friction disc temperature satisfies the first predetermined condition and/or when the current the oil temperature satisfies the second predetermined condition. Thus, the driver is reminded to slow down the vehicle when the friction disc temperature becomes excessively high or the current oil temperature becomes excessively high in order to reduce the possibility of friction disc ablative failure.

[0111] For example, the first predetermined condition may be that the temperature of the friction disc is greater than 190°C, and the second predetermined condition may be that the current oil temperature is greater than 130°C. If the friction disc temperature satisfies the first predetermined condition or the current oil temperature satisfies the second predetermined condition, an overheat protection signal can be sent to the vehicle, reminding the driver that the AWD system has overheated and the vehicle should be slowed down. The transmission of the overtemperature protection signal is terminated when the friction disc temperature does not meet the first set condition and the current oil temperature does not meet the second set condition.

[0112] In practical use, the overheat protection signal may be part of the textual information displayed on the instrument screen in the vehicle, or may be an overheat alarm.

[0113] In this embodiment of the present invention, in accordance with the temperature of the friction disc calculated in step 207, the method further includes step 210.

[0114] In step 210, a temperature correction factor is calculated according to the temperature of the friction disc.

[0115] In practical use, there is a correspondence between the coefficient of friction of the friction disc and the temperature of the friction disc. Calculating the temperature correction factor according to the temperature of the friction disc can improve the calculation accuracy of the output torque. The temperature correction factor can be calibrated based on the actual condition of the vehicle to improve the accuracy of the temperature correction factor.

[0116] In step 211, a temperature-compensated output torque is obtained based on the calculated output torque and the temperature correction factor.

[0117] In practice, the temperature-compensated output torque can be obtained by multiplying the calculated output torque by the temperature correction factor. Compared with the calculated output torque, the temperature-compensated output torque takes into account the influence of the friction disc temperature on the actual output torque to improve the accuracy of the calculation of the actual output torque and prevent excessive or inadequate output torque in the vehicle.

[0118] In step 212, a moment of resistance is calculated based on the difference between the speeds of rotation of the front and rear wheels.

[0119] In practical use, the actual output torque also takes into account the moment of resistance due to the difference in speed between the front and rear wheels. Taking into account the moment of resistance can further improve the accuracy of calculating the actual output torque and improve the accuracy of vehicle control.

[0120] In step 213, the actual output torque is obtained based on the drag torque and the temperature compensated output torque.

[0121] Based on the above steps, the actual output torque can be obtained with high accuracy as the sum of the drag torque and the temperature-compensated output torque, which improves the control accuracy of the vehicle output torque.

[0122] At step 214, the friction clutch of the vehicle is controlled to generate the actual output torque.

[0123] Thus, the all-wheel drive intelligent control method according to this embodiment of the present invention provides at least the following advantages.

[0124] In the all-wheel drive intelligent control method described in this embodiment, the friction disc temperature and drag moment can be calculated based on the difference between the speeds of rotation of the front and rear wheels; the temperature-compensated output torque is obtained based on the temperature of the friction disc; the actual output torque is obtained based on the drag torque and the temperature compensated output torque. Thus, the actual output torque is obtained by correcting the estimated output torque according to the temperature of the friction disc, and then combined with the resistance torque, and therefore, the control accuracy of the actual output torque is improved, the vehicle's maneuverability and the vehicle's ability to get out of difficult situations are improved. In addition, due to the transmission of the overheating protection signal to the vehicle, the possibility of ablative failure of the friction disc is reduced, and the service life of the friction clutch is increased.

[0125] It should be noted that for clarity of description, embodiments of the method according to the invention are described as a sequence of operations. However, it will be apparent to those skilled in the art that the invention is not limited to the sequence of steps described and, according to the invention, some of the steps may be performed in a different sequence or performed simultaneously. Moreover, those skilled in the art will appreciate that the embodiments of the invention described herein are the preferred embodiments, and all of the steps described are not required for the embodiments of the present invention.

[0126] Embodiment 3 of the present invention

[0127] FIG. 3 is a block diagram of a four-wheel drive intelligent control system according to one embodiment of the present invention. As shown in FIG. 3, the all-wheel drive intelligent control system is mainly for a vehicle, and includes a receiving unit 301, a torque calculation unit 302, a temperature calculation unit 303, and a torque control unit 304. The receiving module 301 is connected to the torque calculation module 302 and the temperature calculation module 303 . The torque calculation module 302 is connected to the temperature calculation module 303 and the torque control module 304 .

[0128] In FIG. 4 schematically shows the control process of the four-wheel drive intelligent control system according to an embodiment of the present invention. As shown in FIG. 4, the receiving module 301 is configured to receive vehicle state information 3011, wherein the vehicle state information 3011 includes front wheel speed and rear wheel speed. In practical application, the vehicle state information 3011 further includes vehicle speed, steering angle, transmission switch position, engine torque, ambient temperature, stop time, transmission ratios, rotation radius, wheelbase, steering angle ratio and so on.

[0129] The torque calculation module 302 is configured to calculate the estimated output torque 3021 based on the vehicle state information ZON. For example, torque calculation module 302 may be configured to calculate estimated output torque 3021 based on wheel speed, engine torque, transmission signal, vehicle steering angle signal, and the like.

[0130] The temperature calculation module 303 is configured to calculate the vehicle friction disc temperature 3034 based on the front wheel speed, the rear wheel speed, and the calculated output torque 3021.

[0131] For example, the temperature calculation module 303 is configured to calculate the front and rear wheel speed difference 3031 based on the front wheel speed and the rear wheel speed, and calculate the heat generation 3032 in the vehicle friction disc based on the front and rear wheel speed difference 3031 and calculated output torque 3021. In practice, heat generation 3032 in the friction disc is associated not only with the estimated output torque 3021, but also heat generation in the friction disc due to the difference 3031 in the speeds of rotation of the front and rear wheels. In this embodiment of the present invention, the difference 3031 between the speeds of rotation of the front and rear wheels is taken into account in the calculation of heat generation 3032 in the friction disc in order to improve the accuracy of the calculation of the temperature 3034 of the friction disc.

[0132] In this embodiment of the present invention, friction disc heat dissipation 3033 is calculated based on heat generation 3032 in the friction disc. For example, the temperature calculation module 303 is further configured to obtain the previous temperature of the oil in which the friction disk is immersed, calculate the friction disk heat dissipation 3033 based on the previous temperature, and calculate the friction disk temperature 3034 based on the friction disk heat generation 3032 and the friction disk heat dissipation 3033 .

[0133] In FIG. 5 schematically shows a calculation model for calculating the temperature of a friction disc, comprising a temperature calculation module according to an embodiment of the invention. As shown in FIG. 5, the front and rear wheel speed difference 3031 and the calculated output torque 3021 are taken into account. For example, the correction factor is chosen using one-dimensional table interpolation (1-D lookup table function) of the Matlab package. The correction factor is multiplied by the calculated output torque 3021 to obtain the friction disc input torque that actually acts on the friction disc. The input torque of the friction disc is multiplied by the difference 3031 between the speeds of rotation of the front and rear wheels to obtain the work done by sliding friction, which is the main source of heat generation 3032 in the friction disc. The friction disc heat dissipation 3033 is then subtracted from the work done by the sliding friction to obtain the friction disc temperature variation 3034 . Friction disc temperature 3034 can be obtained by integrating this variation.

[0134] After the friction disc temperature 3034 is determined, according to this embodiment of the present invention, the torque calculation module 302 is further configured to correct the estimated output torque 3021 according to the friction disc temperature 3034 to obtain the actual output torque 3024.

[0135] For example, the torque calculation module 302 is further configured to: calculate a temperature correction factor according to the friction disc temperature 3034; obtaining a temperature-compensated output torque 3023 based on the calculated output torque 3021 and the temperature correction factor; calculating the moment of resistance 3022 based on the difference 3031 between the speeds of rotation of the front and rear wheels; and deriving the actual output torque 3024 based on the drag torque 3022 and the temperature compensated output torque 3023.

[0136] For practical use, in FIG. 6 schematically shows a computational model in a torque calculation module according to another embodiment of the present invention. As shown in FIG. 6, the torque calculation module 302 has two parts: correcting the estimated output torque 3021 according to the friction disc temperature 3034; and calculating the moment of resistance 3022 according to the difference 3031 between the speeds of rotation of the front and rear wheels. Friction disc temperature 3034 and difference 3031 between front and rear wheel speeds are input to torque calculation module 302 . The temperature correction coefficient is obtained by functional calculation from the friction disc temperature 3034 . For example, the temperature correction factor is chosen using one-dimensional table interpolation (1-D lookup table function) of the Matlab package. The temperature correction factor can be calibrated based on the actual condition of the vehicle to improve the accuracy of the temperature correction factor. The temperature compensated output torque 3023 can be obtained by multiplying the calculated output torque 3021 by a temperature correction factor. The sum of the temperature compensated output torque 3023 and the drag torque 3022 is taken as the actual output torque 3024.

[0137] In practical application, the front-rear wheel speed difference 3031 needed for the torque calculation module 302 may be obtained by recalling the front-rear wheel speed difference 3031 calculated in the temperature calculation module 303, or may be calculated based on speeds of rotation of the front wheels and rear wheels, which is not a limitation.

[0138] In this embodiment of the present invention, a Proportion-Integral-Differential (PID) feedback is set between the actual output torque 3024 and the calculated output torque 3021 to adjust the input signal magnitude, improve the accuracy of the output torque in intelligent all-wheel drive control system, improve the vehicle's maneuverability, the vehicle's ability to get out of difficult situations and reduce the intensity of noise and vibration (NVH, Noise-Vibration-Harshness).

[0139] In this embodiment of the present invention, the torque control module 304 304 is configured to control the friction clutch to generate the actual output torque 3024 and meet the actual needs of the vehicle. In this example, the torque control module 304 may be configured to: obtain, based on the calculated output torque 3024, the current required for the friction clutch; and control the friction clutch using this current to generate the actual output torque 3024. Thus, the likelihood of ablative failure of the friction disc is reduced while meeting the actual needs of the vehicle.

[0140] In this embodiment of the present invention, based on the obtained temperature 3034 of the friction disc, the temperature calculation module 303 is further configured to calculate the current temperature 3037 of the oil in which the friction disc is immersed, based on heat dissipation by the friction disc 3033, vehicle speed, and ambient temperature. .

[0141] In another example, the heat dissipation of the friction disc 3033 is used to calculate the heat absorbed by the oil 3035; and the vehicle speed and ambient temperature are used to calculate the heat dissipation 3036 of the oil. The current oil temperature 3037 is obtained by subtracting the heat dissipation 3036 of the oil from the heat absorbed by the oil 3035.

[0142] In FIG. 7 schematically shows a calculation model for calculating the current oil temperature included in the temperature calculation module according to another embodiment of the present invention. As shown in FIG. 7, the input signal to the temperature calculation module 303 comprises oil absorbed heat 3035 and vehicle state information 3011. The vehicle state information 3011 includes vehicle speed and ambient temperature. The correspondence between the vehicle speed, the ambient temperature and the oil heat dissipation 3036 is stored in advance in the temperature calculation module 303 . For example, the oil heat dissipation 3036 corresponding to the current vehicle speed and ambient temperature can be obtained by 2-D lookup table function of the Matlab package; then calculate the difference between the heat absorbed by the oil 3035 and the heat dissipated 3036 by the oil, this difference is divided by the specific heat of the oil to obtain the oil temperature variation; and the current oil temperature 3037 is obtained by integrating the oil temperature variation.

[0143] In this embodiment of the present invention, the all-wheel drive intelligent control system further comprises an overheat protection module 305 . The overheat protection module 305 is connected to the temperature calculation module 303 . The overheat protection module 305 is configured to send an overheat protection signal to the vehicle when the friction disc temperature 3034 satisfies the first predetermined condition and/or when the current oil temperature 3037 satisfies the second predetermined condition.

[0144] The specific description of the first predetermined condition and the second predetermined condition is detailed in the second embodiment of the present invention and is omitted here.

[0145] In FIG. 8 is a schematic representation of a computational model in an overtemperature protection module according to another embodiment of the present invention. As shown in FIG. 8, the input to the overheat protection module 305 contains the friction disc temperature 3034 and the current oil temperature 3037. Friction disc temperature 3034 is compared to the first predetermined condition, and current oil temperature 3037 is compared to the second predetermined condition. An overheat protection signal is transmitted to the vehicle when the friction disc temperature 3034 satisfies the first predetermined condition and/or when the current oil temperature 3037 satisfies the second predetermined condition. The vehicle enters the overheat protection mode and sends an overheat signal to the vehicle. The device in the vehicle receives and displays the overheating protection signal, or the warning light in the vehicle gives out the overheating protection warning to remind the driver to slow down the vehicle. The four-wheel drive intelligent control system automatically disables the overheating protection mode if the friction disc temperature 3034 does not meet the first predetermined condition and the current oil temperature 3037 does not meet the second predetermined condition.

[0146] By providing the overheating protection module according to this embodiment of the present invention, the automatic overload protection capability of the intelligent four-wheel drive control system is improved, which increases the service life of the friction clutch.

[0147] In practical application, the receiving module 301, the torque calculation module 302, the temperature calculation module 303, the torque control module 304, and the overheating protection module 305 are combined in an intelligent four-wheel drive control system electronic unit, and several modules work in parallel to improve calculation speed and reduce the time spent on the calculation.

[0148] Thus, the intelligent four-wheel drive control system according to the embodiment of the present invention has at least the following advantages.

[0149] In the all-wheel drive intelligent control system described in this embodiment of the present invention, the estimated output torque of the vehicle can be calculated based on the state information of the vehicle; then calculating the difference between the speeds of rotation of the front and rear wheels based on the speed of the front wheels and the speed of the rear wheels; the temperature of the friction disc of the vehicle can be calculated based on the difference between the speeds of rotation of the front and rear wheels and the estimated output torque; the actual output torque is obtained by adjusting the estimated output torque according to the temperature of the friction disc, and the friction clutch of the vehicle is controlled to generate the actual output torque. In the all-wheel drive intelligent control system proposed in the embodiments of the present invention, the friction disc temperature is obtained directly from the real-time vehicle state information, and this provides higher accuracy; in addition, the estimated output torque is corrected according to the temperature of the friction disc, which improves the control accuracy of the output torque, thereby improving the vehicle's maneuverability and the vehicle's ability to get out of difficult situations, and also reduces the possibility of ablative failure of the friction disc.

[0150] Embodiments of the device according to the present invention, which are similar to the embodiments of the method according to the present invention, are described briefly, and for their understanding, reference may be made to the description of the embodiments of the method according to the present invention.

[0151] In addition, the present invention relates to a vehicle. This vehicle includes a four-wheel drive intelligent control system according to embodiments of the present invention. The specific structure and general principles of the intelligent four-wheel drive control system are described in detail in the above embodiments of the present invention and are omitted here.

[0152] In the vehicle according to the present embodiment of the present invention, comprising an intelligent all-wheel drive control system, the friction disc temperature can be obtained directly based on real-time vehicle state information, and the estimated output torque can be corrected in accordance with the friction disc temperature to improve the accuracy of output torque control, and in turn improve the vehicle's maneuverability and vehicle's ability to get out of difficult situations, as well as reduce the possibility of friction disc ablative failure.

[0153] Preferred embodiments of the present invention are described above, but the present invention is not limited thereto. Any changes, equivalent replacements, improvements made within the principles of the present invention are within the scope of the present invention.

[0154] The embodiments of the apparatus described above are merely illustrative. A unit described as a discrete component may or may not be physically separated. Components shown as blocks may or may not be physical blocks, i.e. the components may be located in the same location or may be distributed among multiple network blocks. All or part of the blocks may be selected based on the actual implementation needs of the technical solutions according to the embodiments of the present invention. Those skilled in the art will readily understand and practice the present invention without additional creative effort.

[0155] Various embodiments of the components of the present invention may be implemented as hardware or software modules running on one or more processors, or as a combination of both. It will be appreciated by those skilled in the art that a microprocessor or a digital signal processor (DSP) may be practiced to implement some or all of the functions of some or all of the components of a computing device according to embodiments of the present invention. Alternatively, the present invention may be implemented as a device or program (such as a computer program and a computer program product) for performing some or all of the methods described above. Such a program for implementing the present invention may be stored on a computer-readable medium, or may be in the form of one or more signals. Such signals may be downloaded from Internet sites, implemented on carrier signals, or in any other form.

[0156] For example, in FIG. 9 shows a computing device configured to perform the method of the present invention. Conventionally, a computing device includes a processor 1010 and a computer program product or computer-readable medium in the form of a memory 1020. The memory 1020 may be electronic memory such as flash memory, electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM) , hard disk, read-only memory (ROM). Memory 1020 has a location 1030 for storing program code 1031 for performing any of the steps of the above method. For example, the program code storage location 1030 may contain various program codes 1031 for performing various steps in the methods described above. The program code may be read from or written to one or more computer program products. A computer program product includes a hard disk, compact disc (CD), memory card, floppy disk, or other media for storing program code. The computer program product is typically a mobile storage unit or a fixed storage unit, as shown in FIG. 10. The storage unit may have storage segments, storage spaces, and the like organized in the same manner as memory 1020 in the computing device of FIG. 9. The program code may, for example, be compressed into an acceptable form. Typically, the storage device contains a computer readable code 1031' that can be read by a processor such as, for example, processor 1010. This code, when executed by the computing device, causes the computing device to perform the steps of the method described above.

[0157] As used herein, the terms “an embodiment of the present invention,” “embodiments of the present invention,” or “one or more embodiments of the present invention” indicate that a particular feature, structure, or characteristic described in connection with some embodiment of the present invention , is included in at least one embodiment of the present invention. In addition, it should be noted that the expression "in an embodiment of the present invention" does not necessarily refer to the same embodiment of the present invention.

[0158] Numerous specific details are set forth herein. However, it is clear that embodiments of the present invention may be practiced without these specific details. In some cases, known methods, structures, and technical solutions are not described in detail so as not to overload the description.

[0159] In the claims, any parenthesized references should not be construed as limitations. The word "comprising" does not exclude the presence of elements or steps not listed in a claim. A single number for an element does not preclude the presence of more than one such element. The present invention may be implemented by hardware, including several different elements, and by a suitably programmed computer. In a claim that lists multiple features, some of those features may be implemented within the same hardware. The use of the words "first", "second", "third", etc. does not denote a strict sequence, and these words can be interpreted as names.

[0160] Finally, it should be noted that the above embodiments of the invention are only intended to describe the technical solutions within the scope of the invention, and should not be interpreted as limiting it. Although the present description has been described in detail with reference to the embodiments, those skilled in the art will appreciate that modifications can be made to the technical solutions set forth in the above embodiments, or equivalent substitutions can be made to certain technical features in the embodiments of the invention. Such modifications or substitutions do not mean that the nature of the technical solution deviates from the scope of the technical solutions described in the embodiments of the invention.

Claims (43)

1. A method for intelligent control of all-wheel drive, including: obtaining information about the state of the vehicle, which includes the speed of the front wheels of the vehicle and the speed of the rear wheels of the vehicle; calculating an estimated output torque based on the vehicle state information; calculating the vehicle friction disc temperature based on the front wheel speed, the rear wheel speed, and the estimated output torque; correcting the calculated output torque according to the calculated friction disc temperature to obtain the actual output torque; And friction clutch control to generate actual output torque. 2. The method of claim 1, wherein the step of calculating the vehicle friction disc temperature based on front wheel speed, rear wheel speed, and estimated output torque comprises: calculating a speed difference between the front and rear wheels based on the speed of the front wheels and the speed of the rear wheels; And calculating the temperature of the friction disc of the vehicle based on the difference between the speeds of rotation of the front and rear wheels and the estimated output torque. 3. The method of claim 2, wherein the step of calculating the vehicle friction disc temperature based on the difference between front and rear wheel speeds and the estimated output torque comprises: calculating heat generation in the friction disc of the vehicle based on the difference between the speeds of rotation of the front and rear wheels and the estimated output torque; obtaining the previous value of the oil temperature at the location of the friction disc; calculating the heat dissipation of the friction disc based on the previous temperature value; And calculation of friction disc temperature based on heat generation in the friction disc and heat dissipation by the friction disc. 4. The method of claim 3, wherein the vehicle state information further comprises a vehicle speed and an ambient temperature, and after performing the step of calculating the friction disc temperature based on heat generation in the friction disc and heat dissipation by the friction disc, the method further comprises: calculating a current oil temperature at a location of the friction disc based on heat dissipation by the friction disc, vehicle speed, and ambient temperature; And transmitting an overheat protection signal to the vehicle when the friction disc temperature satisfies the first predetermined condition and/or when the current oil temperature satisfies the second predetermined condition. 5. The method of claim. 2, in which the step of correcting the calculated output torque in accordance with the temperature of the friction disk to obtain the actual output torque includes: calculating a temperature correction factor based on the temperature of the friction disc; obtaining a temperature-compensated output torque based on the calculated output torque and the temperature correction factor; calculation of the moment of resistance based on the difference between the speeds of rotation of the front and rear wheels; And obtaining the actual output torque based on the drag torque and the temperature-compensated output torque. 6. A four-wheel drive intelligent control system, comprising a receiving module, a torque calculation module, a temperature calculation module, and a torque control module, in which the receiving module is connected to the torque calculation module and the temperature calculation module, and the torque calculation module is connected to the temperature calculation module and the torque control module; the receiving module is configured to obtain vehicle state information, wherein the vehicle state information includes a front wheel speed and a rear wheel speed of the vehicle; the torque calculation module is configured to calculate the estimated output torque based on the vehicle state information; the temperature calculation module is configured to calculate the temperature of the friction disc of the vehicle based on the speed of the front wheels, the speed of the rear wheels and the estimated output torque; the torque calculation module is further configured to correct the calculated output torque according to the temperature of the friction disc to obtain the actual output torque, and the torque control module is configured to control the friction clutch to generate the actual torque output. 7. The system of claim 6, wherein the temperature calculation module is configured to calculate a vehicle friction disc temperature based on front wheel speed, rear wheel speed, and estimated output torque, wherein the temperature calculation module is further configured to: calculating a front and rear wheel speed difference based on the front wheel speed and the rear wheel speed, and calculating a heat generation in the vehicle friction disc based on the front and rear wheel speed difference and the estimated output torque; And obtaining a historical value of the oil temperature at the location of the friction disk, calculating the heat dissipation of the friction disk based on the previous temperature value, and calculating the temperature of the friction disk based on the generation of heat in the friction disk and the heat dissipation of the friction disk. 8. The system of claim 7, wherein the vehicle state information further comprises vehicle speed and ambient temperature, and the system further comprises an overheat protection module, wherein the overheating protection module is connected to the temperature calculation module; the temperature calculation module is further configured to calculate the current oil temperature at the location of the friction disc based on the heat dissipation of the friction disc, the vehicle speed, and the ambient temperature; And the overheat protection module is configured to send an overheat protection signal to the vehicle when the friction disc temperature satisfies the first predetermined condition and/or when the current oil temperature satisfies the second predetermined condition. 9. The system of claim 7, wherein the torque calculation module is further configured to correct the estimated output torque according to friction disc temperature to obtain the actual torque output, wherein the torque calculation module is further configured to: calculating a temperature correction factor according to the temperature of the friction disc; obtaining a temperature-compensated output torque based on the calculated output torque and the temperature correction factor; calculating the moment of resistance based on the difference between the speeds of rotation of the front and rear wheels; And obtaining the actual output torque based on the drag torque and the temperature compensated output torque. 10. A vehicle containing an intelligent all-wheel drive control system according to any one of paragraphs. 6-9. 11. A computer-readable medium storing a computer program containing a computer-readable code, the execution of which in a computer device causes this computer device to carry out the four-wheel drive intelligent control method according to any one of paragraphs. 1-5.

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