A mountain road cruise control method for new energy vehicles

Abstract

The present invention provides a method for mountain cruise control for new energy vehicles, comprising: entering mountain cruise control mode when conditions for enabling mountain cruise control are met; controlling vehicle speed based on slope conditions, including outputting torque before releasing the accelerator in uphill conditions, and obtaining the target vehicle speed at different torques based on vehicle speed and slope differences; obtaining the target vehicle speed under regenerative torque or hydraulic braking force according to battery charge in downhill conditions; and immediately exiting the mode when conditions for exiting mountain cruise control are met. The present invention facilitates rapid and convenient entry and exit of MCC mode. The control method adaptively adjusts and controls driving torque and energy recovery torque, enabling the vehicle to maintain a suitable stable speed both uphill and downhill, thus reducing energy consumption and emissions. Users do not need to control the accelerator or brakes most of the time, resulting in a safe and comfortable driving experience and reduced driver fatigue.

Description

Technical Field

[0001] The present invention relates to the field of cruise control for new energy vehicles, and more specifically, to a mountain road cruise control method for new energy vehicles in mountain road scenarios. Background Art

[0002] The vehicle's Adaptive Cruise Control (ACC) allows the driver to set a fixed speed in good road conditions such as highways. When there is no target speed ahead, the vehicle maintains the set speed. When there is a vehicle blocking the way ahead, the vehicle can actively brake to reduce speed and follow the vehicle in front through auxiliary sensors such as radar or cameras. This can relieve driver fatigue and save energy.

[0003] However, on complex mountain roads with numerous uphill and downhill slopes and curves, the speed range is very variable, making it difficult to set a suitable fixed target speed. On curves, the target vehicle will quickly accelerate to the set target speed, forcing the driver to use more braking to reduce the speed to the appropriate cornering speed. Driving on mountain roads is prone to sudden acceleration and deceleration, which greatly exceeds the expected battery consumption of electric vehicles. Frequent braking frequently causes the adaptive cruise control function to be frequently deactivated, and reactivation requires manual resetting via the paddle shifter. Therefore, adaptive cruise control is almost useless on mountain roads.

[0004] On the other hand, new energy vehicles can save energy when driving downhill on mountain roads through recuperation. However, most electric vehicles currently have only two recuperation settings: strong and weak. These settings have significantly different energy recovery values ​​and are often not well suited to downhill driving. In strong coasting recuperation, when driving downhill at varying gradients, the vehicle's speed drops rapidly after releasing the accelerator, forcing the driver to actively step on the accelerator to increase the necessary speed. In weak recuperation, the vehicle's speed increases rapidly on even slightly steeper slopes, requiring the driver to apply the brakes to control speed, which increases the thermal load on the hydraulic friction brakes. This results in uneconomical energy consumption during extended downhill driving, fatigue, and poor driving comfort. Summary of the Invention

[0005] It is to be understood that both the foregoing general description and the following detailed description of the present disclosure are exemplary and explanatory and are intended to provide further explanation of the disclosure.

[0006] To address the pain points of current adaptive cruise control functions and energy recovery, the present invention proposes a mountain cruise control (MCC) system and method. When going uphill, the driver can release the accelerator pedal at any time, and the power system will adaptively and dynamically adjust the torque to maintain the driver's desired speed. When going downhill, the driver can release the brake pedal at any time, and in most cases the ESC energy recovery system will adaptively and dynamically adjust the feedback torque to maintain the driver's desired speed.

[0007] In order to solve the above technical problems, the present invention provides a mountain road cruise control method for a new energy vehicle, characterized in that the control method includes:

[0008] Step 1: Enter the mountain cruise control mode when the conditions for turning on the mountain cruise control are met;

[0009] Step 2: Controlling the vehicle speed based on the slope, including outputting the torque before releasing the accelerator in an uphill condition, and obtaining the target vehicle speed at different torques based on the vehicle speed difference and the slope difference; and obtaining the target vehicle speed in a downhill condition by selecting the regenerative torque or hydraulic braking force based on the battery charge;

[0010] Step 3: When the mountain cruise control exit conditions appear, exit the mode immediately.

[0011] Preferably, the present invention further provides a method for mountain road cruise control of a new energy vehicle, characterized in that, under uphill conditions, step 2 further comprises:

[0012] Step 2 a1, taking the output torque at the moment of releasing the accelerator as the initial value;

[0013] Step 2 b1: collect the current vehicle speed and longitudinal acceleration in real time to obtain the speed difference and slope difference between the target vehicle speed and the initial slope:

[0014] When the current vehicle speed is lower than the target vehicle speed, the output torque is increased; when the current vehicle speed is higher than the target vehicle speed, the output torque is reduced;

[0015] When the slope difference is a positive value, the output torque is increased, and when the slope difference is a negative value, the output torque is reduced;

[0016] Step 2 c1, further determining when the current vehicle speed is close to the target vehicle speed:

[0017] ΔV / V0<±5%

[0018] If the condition is met, the output torque of the previous cycle is maintained and the process returns to step 2 b1;

[0019] If the condition is not met, the power system model calculates the output torque according to the speed difference and the gradient difference, and then returns to step 2 b1.

[0020] Preferably, the present invention further provides a mountain road cruise control method for a new energy vehicle, characterized in that, under downhill conditions, the step 2 further comprises:

[0021] Step 2 a2: When the battery is not fully charged, output feedback torque according to the current longitudinal acceleration;

[0022] Step 2 b2: collecting the current vehicle speed and longitudinal acceleration in real time to obtain the speed difference and slope difference between the target vehicle speed and the initial slope. When the slope difference is negative, the feedback torque is increased; when the slope difference is positive, the feedback torque is reduced.

[0023] Step 2 c2, when the current vehicle speed is close to the target vehicle speed, further determine:

[0024] ΔV / V0<±5%

[0025] If the condition is met, the feedback torque of the previous cycle is maintained and the process returns to step 2 b2;

[0026] If the condition is not met, the feedback torque is calculated according to the speed difference and the slope difference, and then the process returns to step 2 b2.

[0027] Preferably, the present invention further provides a mountain road cruise control method for a new energy vehicle, characterized in that, under downhill conditions, the step 2 further comprises:

[0028] Step 2 a3: When the battery is fully charged, output the hydraulic braking force according to the current longitudinal acceleration;

[0029] Step 2 b3: collecting the current vehicle speed and longitudinal acceleration in real time to obtain a real-time speed difference and a real-time slope difference. When the real-time slope difference is negative, the hydraulic braking force is increased; when the real-time slope difference is positive, the hydraulic braking force is reduced.

[0030] Step 2 c3, further determining when the current vehicle speed is close to the target vehicle speed:

[0031] ΔV / V0<±5%

[0032] If the condition is met, the hydraulic braking force of the previous cycle is maintained and the process goes to step 2 b3;

[0033] If the condition is not met, the hydraulic braking force is calculated based on the real-time speed difference and the real-time slope difference, and then the process goes to step 2 b3.

[0034] Preferably, the present invention further provides a method for mountain road cruise control of a new energy vehicle, characterized in that the conditions for starting mountain road cruise control in step 1 include simultaneously satisfying:

[0035] Press the function trigger button, the current vehicle speed is within the trigger speed range and the gear is D.

[0036] Preferably, the present invention further provides a mountain road cruise control method for a new energy vehicle, characterized in that the method further comprises the following steps between step 1 and step 2:

[0037] The throttle-brake switching time interval is greater than or equal to 0.5 seconds as a condition for entering the mountain cruise control. If the condition is not met, the manual driving state is maintained. If the condition is met, a prompt is given to enter the mountain cruise control mode.

[0038] Preferably, the present invention further provides a method for mountain road cruise control for a new energy vehicle, wherein the activation conditions of step 1 include:

[0039] The current vehicle speed meets the trigger speed range of 10kph to 80kph.

[0040] Preferably, the present invention further provides a mountain road cruise control method for a new energy vehicle, characterized in that, in step 3, the exit conditions of the mountain road cruise control mode include:

[0041] Any of the following situations occurs: applying the accelerator, braking, external braking request, ESP intervention, ESP controller failure or long pressing the mountain cruise control mode button.

[0042] Compared with the existing technology, the present invention enters and exits the MCC mode conveniently and quickly, without the need for manual setting of the lever, and the control method adaptively adjusts the driving torque and energy recovery torque to enable the vehicle to maintain a suitable stable speed when going uphill and downhill, which can greatly save battery power consumption and achieve energy conservation and emission reduction; since the user does not need to control the throttle or brake most of the time, the driving experience is safe and comfortable, and driving fatigue is reduced; in addition, it also has certain practicality in fuel vehicles. There is no energy recovery in traditional fuel vehicles, and the function can be realized by simply changing the downhill energy recovery torque control model to a simple hydraulic brake control model. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. Reference will now be made in detail to preferred embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numerals will be used throughout the drawings to represent the same or similar parts. In addition, although the terms used in this disclosure are selected from commonly known and commonly used terms, some of the terms mentioned in this disclosure may be selected by the applicant at his or her discretion, and their detailed meanings are explained in the relevant parts of the description herein. In addition, it is required that the present disclosure be understood not only by the actual terms used, but also by the meaning implied by each term.

[0044] The above and other objects, features and advantages of the present invention will become apparent to those skilled in the art from the detailed description of the present invention with reference to the accompanying drawings below.

[0045] Figure 1 Shown is a flow chart of the MCC mode implementation of the present invention;

[0046] Figure 2 This is the uphill or downhill speed control flow chart in MCC mode;

[0047] Figure 3 is a graph showing the relationship between energy recovery value and vehicle deceleration in the present invention;

[0048] Figure 4 It is a curve diagram showing the relationship between the ESC hydraulic brake pressure and the vehicle deceleration in the present invention. DETAILED DESCRIPTION

[0049] To more clearly illustrate the technical solutions of the embodiments of this application, the following is a brief introduction to the drawings required for describing the embodiments. Obviously, the drawings described below are merely examples or embodiments of this application. Those skilled in the art can apply this application to other similar scenarios based on these drawings without inventive effort. Unless otherwise apparent from the context or otherwise noted, the same reference numerals in the figures represent the same structure or operation.

[0050] As used in this application and the claims, unless the context clearly indicates otherwise, the words "a," "an," "an," and / or "the" are not intended to refer to the singular but may include the plural. Generally speaking, the terms "comprises" and "include" only indicate the inclusion of the steps and elements specifically identified, and these steps and elements do not constitute an exclusive list. A method or apparatus may also include other steps or elements.

[0051] Unless otherwise specifically stated, the relative arrangement of the parts and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present application. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the drawings are not drawn according to actual proportional relationships. The techniques, methods and equipment known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the techniques, methods and equipment should be considered as part of the authorization specification. In all examples shown and discussed here, any specific values ​​should be interpreted as being merely exemplary and not as limitations. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that similar numbers and letters represent similar items in the following figures, and therefore, once an item is defined in one figure, it does not need to be further discussed in subsequent figures.

[0052] In the description of this application, it should be understood that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "horizontal, vertical, vertical, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of this application; the directional words "inside and outside" refer to the inside and outside relative to the outline of each component itself.

[0053] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used herein to describe the spatial positional relationship of a device or feature to other devices or features as shown in the figures. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figures. For example, if the device in the drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0054] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is solely for the purpose of distinguishing the corresponding components. Unless otherwise stated, these terms have no special meaning and therefore should not be construed as limiting the scope of protection of this application. Furthermore, while the terms used in this application are selected from commonly known and commonly used terms, some terms mentioned in this specification may have been selected by the applicant at his or her discretion, and their detailed meanings are explained in the relevant sections of this description. Furthermore, this application should be understood not only by the actual terms used, but also by the meaning implied by each term.

[0055] Flowcharts are used in this application to illustrate the operations performed by systems according to embodiments of the present application. It should be understood that the preceding or following operations are not necessarily performed in exact order. Instead, the various steps may be processed in reverse order or simultaneously. Furthermore, other operations may be added to these processes, or one or more operations may be removed from these processes.

[0056] The Mountain Cruise Control (MCC) system and method proposed in the present invention allows the driver to release the accelerator pedal at any time when going uphill, and the power system adaptively and dynamically adjusts the torque to maintain the driver's desired speed. When going downhill, the driver can also release the brake pedal at any time, and in most cases the ESC energy recovery system adaptively and dynamically adjusts the feedback torque to maintain the driver's desired speed.

[0057] See Figure 1 The MCC mode flow chart of the present invention is shown.

[0058] Step 1: The vehicle-mounted conditions for starting the MCC mode of the present invention include the following three:

[0059] Condition 1: Is the function trigger button pressed?

[0060] The system of the present invention is equipped with a function trigger button on the driving console. When entering a mountain road, the driver can press the function button and the MCC mode will be in a waiting state. If you want to exit the MCC mode, you can long press the function button.

[0061] Condition 2: Does the current vehicle speed meet the trigger speed?

[0062] The MCC mode can set the speed range for function triggering. Due to the characteristics of the motor, energy recovery will gradually exit below 10kph, resulting in the inability to perform energy recovery braking. In order to ensure safe driving on mountain roads, in the preferred embodiment, the present invention sets the speed range for function triggering to 10kph to 80kph, which can meet most mountain road conditions and enable new energy vehicles to achieve economical, energy-saving and safe driving on mountain roads.

[0063] Condition three: Does the gear meet the D gear?

[0064] In MCC mode, the gear position judgment signal can be set as the triggering premise.

[0065] In a preferred embodiment, D gear is set as the triggering prerequisite for the MCC mode, and the downhill energy recovery model is used to adaptively and dynamically output the appropriate energy recovery value, which overcomes the shortcomings of the current new energy vehicles with two different energy recovery gears. At the same time, the original B gear strong coasting energy recovery mode is retained, and it also avoids unnecessary triggering of the MCC mode when the vehicle is in other gears.

[0066] For example, once the MCC mode is in the waiting state with the function button turned on and the vehicle is in D gear and the speed is between 10kph and 80kph, the MCC working state can be entered as long as the driver releases the brake or accelerator for more than 0.5 seconds.

[0067] Step 2: To avoid frequent switching between the accelerator and brake, a time interval is set. In a preferred embodiment, a time interval of 0.5 seconds is used as the basis for determining whether to enter the vehicle.

[0068] Step 3: If the conditions are not met, the system will not enter the MCC mode and will remain in manual driving mode.

[0069] Step 4: When the above conditions are met, the vehicle turns on the MCC mode, and the MCC mode working indicator light can be set on the instrument to remind the driver that the MCC is in working mode.

[0070] Step 5: In MCC mode, the vehicle speed is controlled according to the uphill or downhill conditions to maintain the target speed;

[0071] Step 6: When the MCC exit condition occurs, exit the function immediately.

[0072] Exit conditions include: applying the accelerator or brake, or external braking request, or ESP intervention, or ESP controller failure, or long pressing the MCC mode button to exit the MCC mode.

[0073] The above conditions are in an OR relationship. Once one condition is met, the exit of the MCC is triggered.

[0074] In the above Figure 1 In the main process given, the specific control process step 5 is involved, and then Figure 2 Give further detailed implementation instructions:

[0075] Step 21, MCC mode triggering, that is, the system enters the MCC mode working mode;

[0076] Step 22: The ESC controller collects the current vehicle speed V0 and longitudinal acceleration signal ax0;

[0077] Specifically, the ESC controller has a wheel speed sensor that can collect wheel speed sensor signals in real time. The ESC controller will calculate the vehicle speed in real time and use the vehicle speed VO when MCC intervenes 0.5 seconds after releasing the accelerator or braking as the target vehicle speed.

[0078] The longitudinal acceleration sensor is built into the ESC controller and can output the value in real time. The longitudinal acceleration when MCC intervenes 0.5 seconds after releasing the accelerator or brake is recorded as ax0.

[0079] In steady state, with neither the brake nor the accelerator pressed, the longitudinal acceleration value roughly corresponds to the slope value. For example, a longitudinal acceleration of 0.1g is equivalent to the vehicle's longitudinal acceleration value on a 10% slope, and a longitudinal acceleration of 0.2g is equivalent to the vehicle's longitudinal acceleration value on a 20% slope. In steady state, with neither the brake nor the accelerator pressed, a positive longitudinal acceleration value indicates an uphill slope, while a negative longitudinal acceleration value indicates a downhill slope.

[0080] Step 23: The system obtains the longitudinal acceleration from the longitudinal acceleration sensor built into the ESC controller and can output the value in real time to determine whether the vehicle is going uphill or downhill.

[0081] Specifically, if the longitudinal acceleration satisfies:

[0082] ax≥0 (1)

[0083] If it is determined to be an uphill driving condition, go to step 24;

[0084] If the longitudinal acceleration does not satisfy formula (1), but is:

[0085] ax<0 (2)

[0086] It is determined to be a downhill condition, and the process goes to step 25;

[0087] Step 241, similar to the principle of cruise control, starts the engine output torque with the torque EM0 at the moment of releasing the accelerator as the initial value.

[0088] Step 242 , the ESC controller collects the vehicle speed V1 and the longitudinal acceleration signal ax1 at that moment in real time;

[0089] Step 243: Calculate the vehicle speed difference and slope difference in real time:

[0090] ΔV=V1-V0 (3)

[0091] Δax=ax1-ax0 (4)

[0092] Where V1 is the current vehicle speed, V0 is the target vehicle speed, ΔV is the speed difference, and Δax is the slope difference;

[0093] For formula (3), when the vehicle speed difference ΔV is negative, that is, the vehicle speed V1 is lower than the target vehicle speed V0, the output torque EM1 is increased;

[0094] When the vehicle speed difference ΔV is positive, that is, the vehicle speed V1 is higher than the target vehicle speed V0, the output torque EM1 is reduced;

[0095] Similarly, an increase or decrease in the slope value will eventually be reflected in a change in vehicle speed.

[0096] For formula (4), under uphill conditions, if the slope difference Δax is a positive value, it means that the slope becomes steeper and the output torque EM1 needs to be increased. If the slope difference Δax is a negative value, it means that the slope becomes gentler and the output torque EM1 needs to be reduced.

[0097] In step 244, through feedback control, the vehicle speed V1 will get closer and closer to the target vehicle speed V0 value, depending on whether:

[0098] ΔV / V0<±5% (5)

[0099] Output torque respectively;

[0100] Step 245: If formula (5) is satisfied, maintain the torque output EM1 of the previous cycle and return to step 242;

[0101] In step 246 , if formula (5) is not satisfied, the power system model calculates the output torque ( EM1 ) based on the speed difference and the slope difference and then returns to step 242 ;

[0102] The above steps 241 to 246 are combined into step 24, which aims to continuously and adaptively adjust the torque to achieve the uphill cruise control function.

[0103] Step 25: When step 23 determines that the vehicle is in a downhill operating condition through ax<0, first determine whether the battery is fully charged.

[0104] Step 261 : If the battery is not fully charged, then use downhill energy regenerative braking to control the downhill speed. Specifically, the ESC controller outputs a regenerative torque RBM0 based on the longitudinal acceleration ax0 .

[0105] Step 262 , the ESC controller collects the vehicle speed V1 and the longitudinal acceleration signal ax1 in real time;

[0106] Step 263, the speed difference and slope difference are calculated in real time as follows:

[0107] ΔV=V1-V0 (6)

[0108] Δax=ax1-ax0 (7)

[0109] Where V1 is the current vehicle speed, V0 is the target vehicle speed, ΔV is the speed difference, and Δax is the slope difference;

[0110] Step 264, based on whether:

[0111] ΔV / V0<±5% (8)

[0112] Output energy feedback torque respectively;

[0113] Step 265: If formula (8) is satisfied, maintain the feedback torque RBM1 of the previous cycle and return to step 262;

[0114] In step 266, if formula (8) is not satisfied, the ESC controller calculates the feedback torque RBM1 according to the speed difference and the slope difference, and returns to step 262;

[0115] The above steps 261 to 266 are combined into step 26, which aims to continuously and adaptively adjust the size of energy recovery to achieve the downhill energy recovery cruise control function.

[0116] Step 271: When it is determined in step 25 that the battery is fully charged, the ESC controller outputs a hydraulic braking force BP0 according to ax0;

[0117] Step 272 , the ESC controller collects the vehicle speed V1 and the longitudinal acceleration signal ax1 in real time;

[0118] Step 273, the speed difference and slope difference are calculated in real time as follows:

[0119] ΔV=V1-V0 (9)

[0120] Δax=ax1-ax0 (10)

[0121] Where V1 is the current vehicle speed, V0 is the target vehicle speed, ΔV is the speed difference, and Δax is the slope difference;

[0122] Step 274, based on whether:

[0123] ΔV / V0<±5% (11)

[0124] Output hydraulic braking force respectively;

[0125] Step 275: When formula (11) is satisfied, the hydraulic braking force BP1 of the previous cycle is maintained and the process proceeds to step 272;

[0126] In step 276 , when formula (11) is not satisfied, the ESC controller calculates the hydraulic braking force BP1 based on the speed difference and the slope difference, and proceeds to step 272 .

[0127] The above steps 271 to 276 are combined into step 27, which aims to continuously and adaptively adjust the magnitude of the hydraulic braking force to achieve the downhill cruise control function.

[0128] On a level road, the ESC controller sends out an energy recovery value corresponding to the vehicle deceleration value. Figure 3 As shown, it is basically a linear relationship.

[0129] Below, we use a certain car model as an example to illustrate step 26:

[0130] For example, when the vehicle is on a 10% downhill slope, the vehicle has a downward component force of approximately 0.1g. In order to maintain the target vehicle speed while moving downward, the initial value of the energy regenerative torque RBM0 can be found in the comparison chart of "energy recovery value and vehicle deceleration" to be 600Nm, corresponding to step 261.

[0131] In steps 262 to 263, the ESC controller collects the vehicle speed and longitudinal acceleration values ​​in real time, and calculates the vehicle speed difference in real time according to formula (6). When ΔV is a negative value, that is, the vehicle speed V1 is lower than the target speed V0, the feedback torque is reduced to RBM1. When ΔV is a positive value, that is, the vehicle speed V1 is higher than the target speed V0, the feedback torque is increased to RBM1.

[0132] Similarly, an increase or decrease in the slope value will ultimately be reflected in a change in vehicle speed. The slope difference Δax is calculated according to formula (7). Since ax1 and ax0 are negative when going downhill, a negative Δax indicates a steeper slope and requires an increase in feedback torque (RBM1). A positive Δax indicates a gentler slope and requires a decrease in feedback torque (RBM1). Through continuous feedback control, the vehicle speed V1 will increasingly approach the target speed V0.

[0133] Enter step 264 and refer to formula (8) for judgment. If the formula is satisfied, then according to step 265, the feedback torque output RBM1 of the previous cycle is maintained; if the judgment is not satisfied, then according to step 266, the ESC system model calculates the feedback torque RBM1 based on the speed difference and the slope difference.

[0134] Figure 4 The relationship between the hydraulic braking force of the ESC controller and the vehicle deceleration on a level road is shown, which is basically a linear relationship. Step 27 is also explained using a certain vehicle model as an example.

[0135] When the vehicle is traveling on a 10% downhill slope, the vehicle has a downward component force of about 0.1g. In order to maintain the target vehicle speed, the vehicle travels downward. According to step 271, the initial value BP0 of the ESC hydraulic braking force can be found as 9 bar by looking up the "ESC hydraulic braking pressure vehicle deceleration" comparison relationship chart.

[0136] According to steps 272 to 273, the ESC controller collects the vehicle speed and longitudinal acceleration values ​​in real time, and calculates the vehicle speed difference ΔV in real time according to formula (9). When ΔV is a negative value, that is, the vehicle speed V1 is lower than the target vehicle speed V0, the hydraulic braking force is reduced to BP1. When ΔV is a positive value, that is, the vehicle speed V1 is higher than the target vehicle speed V0, the hydraulic braking force is increased to BP1. Similarly, the increase or decrease in the slope value will eventually be reflected in the change in vehicle speed; the slope difference Δax is calculated according to formula (10). Since ax1 and ax0 are negative values ​​when going downhill, Δax is a negative value, indicating that the slope becomes steeper and the hydraulic braking force needs to be increased to BP1. Δax is a positive value, indicating that the slope becomes gentler and the hydraulic braking force needs to be reduced to BP1. Through continuous feedback control, the vehicle speed V1 will get closer and closer to the target vehicle speed V0 value,

[0137] In step 274, it is determined whether formula (11) is satisfied. If so, the hydraulic braking force BP1 of the previous cycle is maintained according to step 275. If not, the ESC controller calculates the hydraulic braking force BP1 according to the speed difference and the slope difference according to step 276.

[0138] In summary, the MCC control of the present invention achieves stable target vehicle speed control. It is necessary to adjust the driving torque or energy recovery value or hydraulic braking force in real time at different slopes based on the vehicle conditions, including vehicle weight, motor characteristics, transmission ratio, and driving energy loss, and compare it with the target vehicle speed to achieve feedback control. Figure 2 The values ​​of the control variables EM1, RBM1, and BP1 in the control system need to be matched with appropriate values ​​according to the actual vehicle conditions to achieve fast convergence of feedback control.

[0139] Under complex mountain road conditions, the slope changes at any time, there are many sharp turns, and the vehicle speed fluctuates and needs to be constantly adjusted. Unlike the adaptive cruise control function of ACC, the MCC of the present invention has the following advantages:

[0140] First, the target vehicle speed can be dynamically adjusted at any time by releasing the accelerator or braking for 0.5 seconds and entering the MCC operating condition, which can adapt to complex mountain road conditions at any time; unlike the ACC function, a fixed target vehicle speed needs to be set in advance.

[0141] Second, entering and exiting MCC mode is quick and easy, without the need for manual lever settings;

[0142] Third, adaptively adjusting and controlling the driving torque and energy recovery torque allows the vehicle to maintain a suitable and stable speed when going uphill and downhill, which can significantly save battery power consumption and achieve energy conservation and emission reduction;

[0143] Fourth, most of the time, there is no need to control the accelerator or brake, making the driving experience safe and comfortable, reducing driver fatigue;

[0144] Fifth, it reduces the thermal load of hydraulic friction brakes on long downhill slopes, reduces the risk of thermal decay, and improves driving safety;

[0145] Sixth, no additional sensors or hardware devices are required, only software development is required, saving development costs;

[0146] Seventh, the MCC mode has strong scalability. The present invention is also practical for traditional fuel vehicles. There is no energy recovery in traditional fuel vehicles. The function can be realized by simply changing the downhill energy recovery torque control model to a simple hydraulic braking control model.

[0147] The basic concepts have been described above. It will be apparent to those skilled in the art that the above disclosures are merely illustrative and do not constitute limitations on this application. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements, and amendments to this application. Such modifications, improvements, and amendments are suggested in this application and remain within the spirit and scope of the exemplary embodiments of this application.

[0148] At the same time, this application uses specific terms to describe the embodiments of this application. For example, "one embodiment," "an embodiment," and / or "some embodiments" refer to a certain feature, structure, or characteristic related to at least one embodiment of this application. Therefore, it should be emphasized and noted that "one embodiment," "an embodiment," or "an alternative embodiment" mentioned twice or multiple times in different locations in this specification does not necessarily refer to the same embodiment. In addition, certain features, structures, or characteristics in one or more embodiments of this application may be appropriately combined.

[0149] Some aspects of the present application can be performed entirely by hardware, entirely by software (including firmware, resident software, microcode, etc.), or by a combination of hardware and software. The above hardware or software can be referred to as "data blocks", "modules", "engines", "units", "components" or "systems". The processor can be one or more application-specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DAPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), processors, controllers, microcontrollers, microprocessors or combinations thereof. In addition, various aspects of the present application may be expressed as computer products located in one or more computer-readable media, which include computer-readable program code. For example, computer-readable media may include, but are not limited to, magnetic storage devices (e.g., hard disks, floppy disks, tapes...), optical disks (e.g., compact disks CDs, digital versatile disks DVDs...), smart cards, and flash memory devices (e.g., cards, sticks, key drives...).

[0150] A computer-readable medium may include a propagated data signal embodying computer program code, for example, in baseband or as part of a carrier wave. The propagated signal may be in a variety of forms, including electromagnetic, optical, etc., or a suitable combination thereof. A computer-readable medium may be any computer-readable medium other than a computer-readable storage medium that can be connected to an instruction execution system, apparatus, or device to communicate, propagate, or transmit the program for use. The program code on the computer-readable medium may be transmitted via any suitable medium, including radio, cable, fiber optic cable, radio frequency signal, or similar medium, or any combination of the above.

[0151] The basic concepts have been described above. It will be apparent to those skilled in the art that the above disclosures are merely illustrative and do not constitute limitations on this application. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements, and amendments to this application. Such modifications, improvements, and amendments are suggested in this application and remain within the spirit and scope of the exemplary embodiments of this application.

[0152] At the same time, this application uses specific terms to describe the embodiments of this application. For example, "one embodiment," "an embodiment," and / or "some embodiments" refer to a certain feature, structure, or characteristic related to at least one embodiment of this application. Therefore, it should be emphasized and noted that "one embodiment," "an embodiment," or "an alternative embodiment" mentioned twice or multiple times in different locations in this specification does not necessarily refer to the same embodiment. In addition, certain features, structures, or characteristics in one or more embodiments of this application may be appropriately combined.

[0153] Similarly, it should be noted that, in order to simplify the presentation of this application and thus facilitate understanding of one or more embodiments of the invention, the foregoing descriptions of the embodiments of this application sometimes combine multiple features into a single embodiment, figure, or description thereof. However, this disclosure method does not mean that the subject matter of this application requires more features than those recited in the claims. In fact, an embodiment may have fewer features than all of the features of a single embodiment disclosed above.

[0154] In some embodiments, numbers are used to describe the quantity of components and attributes. It should be understood that such numbers used in the description of the embodiments are modified by the modifiers "about", "approximately" or "substantially" in some examples. Unless otherwise stated, "about", "approximately" or "substantially" indicate that the numbers are allowed to vary by ±20%. Accordingly, in some embodiments, the numerical parameters used in the description and claims are approximate values, which may change according to the required features of individual embodiments. In some embodiments, the numerical parameters should take into account the specified significant digits and adopt the general method of retaining digits. Although the numerical domains and parameters used to confirm the breadth of their range in some embodiments of the present application are approximate values, in specific embodiments, the settings of such numerical values ​​are as accurate as possible within the feasible range.

[0155] Although the present application has been described with reference to the current specific embodiments, ordinary technicians in this technical field should recognize that the above embodiments are only used to illustrate the present application, and various equivalent changes or substitutions can be made without departing from the spirit of the present application. Therefore, as long as the changes and modifications to the above embodiments are within the scope of the essential spirit of the present application, they will fall within the scope of the claims of the present application.

Claims

1. A mountain road cruise control method for a new energy vehicle, characterized in that: The control method includes: Step 1: Enter the mountain cruise control mode when the mountain cruise control activation conditions are met; Step 2: Controlling the vehicle speed based on the slope, including outputting the torque before releasing the accelerator in an uphill condition, and obtaining the target vehicle speed at different torques based on the vehicle speed difference and the slope difference; and obtaining the target vehicle speed in a downhill condition by selecting the regenerative torque or hydraulic braking force based on the battery charge; Step 3: When a mountain road cruise control exit condition occurs, immediately exit the mountain road cruise control mode; Wherein, under the uphill working condition, the step 2 further includes: Step 2 a1, taking the output torque at the moment of releasing the accelerator as the initial value; Step 2 b1: collect the current vehicle speed and longitudinal acceleration in real time to obtain the speed difference and slope difference between the target vehicle speed and the initial slope: When the current vehicle speed is lower than the target vehicle speed, the output torque is increased; when the current vehicle speed is higher than the target vehicle speed, the output torque is reduced; When the slope difference is a positive value, the output torque is increased, and when the slope difference is a negative value, the output torque is reduced; Step 2 c1, further determining when the current vehicle speed is close to the target vehicle speed: ΔV / V0<±5% If the condition is met, the output torque of the previous cycle is maintained and the process returns to step 2 b1; If the condition is not met, the power system model calculates the output torque according to the vehicle speed difference and the slope difference, and then returns to step 2 b1; In downhill conditions, the second step further includes: Step 2 a2: When the battery is not fully charged, output feedback torque according to the current longitudinal acceleration; Step 2 b2: collecting the current vehicle speed and longitudinal acceleration in real time to obtain the speed difference and slope difference between the target vehicle speed and the initial slope. When the slope difference is negative, the feedback torque is increased; when the slope difference is positive, the feedback torque is reduced. Step 2 c2, when the current vehicle speed is close to the target vehicle speed, further determine: ΔV / V0<±5% If the condition is met, the feedback torque of the previous cycle is maintained and the process returns to step 2 b2; If the condition is not met, the feedback torque is calculated according to the vehicle speed difference and the slope difference, and the process returns to step 2 b2; In downhill conditions, the second step further includes: Step 2 a3: When the battery is fully charged, output the hydraulic braking force according to the current longitudinal acceleration; Step 2 b3: collecting the current vehicle speed and longitudinal acceleration in real time to obtain a real-time vehicle speed difference and a real-time slope difference. When the real-time slope difference is negative, the hydraulic braking force is increased; when the real-time slope difference is positive, the hydraulic braking force is reduced. Step 2 c3, further determining when the current vehicle speed is close to the target vehicle speed: ΔV / V0<±5% If the condition is met, the hydraulic braking force of the previous cycle is maintained and the process goes to step 2 b3; If the condition is not met, the hydraulic braking force is calculated based on the real-time vehicle speed difference and the real-time slope difference, and then the process goes to step 2 b3.

2. The mountain road cruise control method for a new energy vehicle according to claim 1, characterized in that: The conditions for enabling mountain cruise control in step 1 include simultaneously meeting the following: Press the function trigger button, the current vehicle speed is within the trigger speed range and the gear is D.

3. The mountain road cruise control method for a new energy vehicle according to claim 2, characterized in that: The steps 1 and 2 further include: The throttle-brake switching time interval is greater than or equal to 0.5 seconds as a condition for entering the mountain cruise control. If the condition is not met, the manual driving state is maintained. If the condition is met, a prompt is given to enter the mountain cruise control mode.

4. The mountain road cruise control method for a new energy vehicle according to claim 3, characterized in that: The start conditions of step 1 include: The current vehicle speed meets the trigger speed range of 10kph to 80kph.

5. The mountain road cruise control method for a new energy vehicle according to claim 3, characterized in that: In step 3, the exit conditions of the mountain road cruise control mode include: Any of the following situations occurs: applying the accelerator, braking, external braking request, ESP intervention, ESP controller failure or long pressing the mountain cruise control mode button.

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