Method for adjusting the coasting energy recovery intensity of electric vehicles suitable for novice transition period

Abstract

The present invention provides a method for adjusting the sliding energy recovery force of an electric vehicle suitable for a novice transition period. The corresponding relationship between the throttle release opening and the standard motor braking torque is stored before the electric vehicle leaves the factory; when the novice transition period mode is started, the number of over-deceleration events and the driving time are recorded during the driving process, and the total number of over-deceleration events in the time interval is counted for every Δt driving time interval, and the value of the correction factor is adjusted. The corresponding braking torque is obtained according to the throttle release opening, and then multiplied by the correction factor to obtain the actual motor braking torque, so that the motor is braked with the actual motor braking torque to generate electrical energy and store it in the battery pack. The method for adjusting the sliding energy recovery force of an electric vehicle of the present invention is simple to operate, highly versatile, low-cost, highly reliable, and user-friendly.

Description

Technical Field

[0001] The present invention relates to the field of electric vehicles, and in particular to a method for adjusting the coasting energy recovery force of an electric vehicle suitable for a novice in a transition period. Background Art

[0002] At present, electric vehicles are becoming more and more popular due to their advantages such as green environmental protection, high efficiency and comfort. Electric vehicles usually use battery pack discharge to drive the motor to travel, and the motor can brake when it reverses and charge the battery pack in turn. Like traditional fuel vehicles, electric vehicles usually also include accelerator pedals and brake pedals. However, the braking and deceleration of traditional fuel vehicles usually only rely on the brake pedal through the friction effect, consuming the vehicle's mechanical energy and converting it into basically unusable heat energy. In addition to mechanical friction braking like traditional fuel vehicles, electric vehicles can also transfer part of the inertial energy of the driving process to the drive motor through the transmission system, allowing the drive motor to operate in a generator mode, driving the motor rotor shaft to rotate, generating electrical energy through the principle of electromagnetic induction, charging the power battery, and realizing energy recycling; at the same time, the electromagnetic induction torque of the drive motor can apply reverse torque to the drive wheel through the transmission system, thereby braking the vehicle.

[0003] For electric vehicles, drivers can brake by either pressing the brake pedal or releasing the accelerator pedal: the former generally includes both mechanical friction braking and motor braking, while the latter generally only includes motor braking, so releasing the accelerator pedal can recover a greater proportion of the vehicle's inertial energy. Represented by Tesla's "single pedal" mode, electric vehicles are increasingly popular with the method of mainly relying on releasing the accelerator to brake, and braking is only used as a supplement in emergency situations. This not only gives electric vehicle drivers a more convenient driving experience, but also can well recover the vehicle's inertial energy to extend the range. According to statistics, when cars are running in urban areas, they accelerate and decelerate frequently, and the energy dissipated by braking accounts for 40-50% of the total driving energy. In some urban working conditions, it is as high as 80%, and in suburban working conditions, at least 20% of the driving energy is lost in the braking process; in electric vehicles, the conversion efficiency of this part of energy from the drive wheel to the battery pack through the electrical system can be as high as about 70%. Braking energy recovery can generally extend the driving range of electric vehicles by 15-20%, which is the key to determining the energy efficiency level of electric vehicles.

[0004] From the perspective of improving the energy efficiency of electric vehicles, the coasting energy recovery strength should be maintained as high as possible. The energy recovery strength is reflected in the relationship between the accelerator pedal opening and the motor braking torque: when the vehicle is coasting (the vehicle is moving forward and the brake pedal and the accelerator pedal are not pressed), if the sensor detects that the driver's accelerator pedal opening is at the maximum, the regenerative braking controller obtains the signal and puts the motor in its maximum braking torque state to achieve the maximum coasting energy recovery. However, there is no braking deceleration effect when the accelerator pedal is released in traditional fuel vehicles. If a novice driver who is accustomed to traditional fuel vehicles transitions from a fuel vehicle to an electric vehicle, due to the huge difference in deceleration effect between traditional fuel vehicles and electric vehicles when releasing the accelerator pedal, the novice driver may not be able to better control the opening of the accelerator pedal during the coasting process of the electric vehicle, resulting in a large deceleration of the vehicle, causing frustration and other driving discomfort. For example, when driving a traditional fuel vehicle at high speed, if the driver suddenly releases the accelerator completely (the accelerator pedal is at the maximum opening), the vehicle will not decelerate significantly immediately, but the driving force will basically disappear, and the vehicle will naturally decelerate slowly under the friction between the tires and the ground and the wind resistance. When driving a general electric vehicle at high speed, if the driver follows the driving habits of traditional fuel vehicles and suddenly releases the accelerator completely (the accelerator pedal is at the maximum opening), in addition to the friction between the tires and the ground and the wind resistance, the motor will often apply a large braking torque to the tires to recover inertial energy and produce a significant deceleration effect.

[0005] Therefore, considering that a large number of drivers have switched from driving traditional fuel vehicles to driving electric vehicles, it is urgent to set up an adjustment method for the coasting energy recovery intensity of electric vehicles for the transition period of novices, to strike a balance between the energy efficiency level of electric vehicles and driving comfort, and to allow novices to gradually adapt to the coasting braking method of electric vehicles. Summary of the invention

[0006] In order to solve the above technical problems, the present invention provides a method for adjusting the coasting energy recovery force of an electric vehicle suitable for a novice transition period, which is simple to operate, highly versatile, low cost, highly reliable, and user-friendly. The method is:

[0007] The electric vehicle stores the correspondence between the accelerator pedal release opening K and the standard motor braking torque M before leaving the factory; when the electric vehicle starts the novice transition mode, the standard motor braking torque M corresponding to the accelerator pedal release opening K is found during driving, and then multiplied by the correction factor f to obtain the actual motor braking torque M′, so that the motor is braked with the actual motor braking torque M′ to generate electrical energy and store it in the battery pack, where the correction factor f is between 0 and 1.

[0008] The above-mentioned method for adjusting the coasting energy recovery strength of an electric vehicle applicable to the novice transition period, the value of the correction factor f is determined as follows: the instantaneous correction factor f when the electric vehicle starts the novice transition period mode is taken as the initial value of the correction factor f0; the number of excessive deceleration events and the driving time are recorded during the driving process, wherein the excessive deceleration event refers to the event in which the vehicle deceleration exceeds the critical deceleration value a0 when only the accelerator pedal is released without pressing the brake pedal; every driving time interval of Δt, the total number of excessive deceleration events N in the time interval is counted and the value of the correction factor f is adjusted:

[0009] (1) If the total number of times N is greater than the critical number of times N0, the value of f-Δf is calculated. If f-Δf>0, the correction factor f is reduced by Δf based on its original value; otherwise, the correction factor f is set to 0;

[0010] (2) If the total number N is equal to the critical number N0, the correction factor f is left unchanged based on its original value;

[0011] (3) If the total number of times N is less than the critical number of times N0, calculate the value of f+Δf. If f+Δf<1, increase the correction factor f by Δf based on its original value; otherwise, set the correction factor f to 1.

[0012] Where Δf is the correction factor change value.

[0013] Furthermore, the initial value f0 of the correction factor is between 0.2 and 0.8.

[0014] Furthermore, the correction factor variation value Δf is between 0.001 and 0.1.

[0015] Furthermore, the critical deceleration value a0 is set at 0.5 m / s 2 Up to 3m / s 2 between.

[0016] Furthermore, the driving time interval Δt is between 0.5 hours and 100 hours, and the critical number of times N0 is between 1 and 500.

[0017] The above-mentioned method for adjusting the coasting energy recovery intensity of an electric vehicle during the novice transition period also includes: if the value of the correction factor f is 1 after C consecutive driving time intervals, the electric vehicle is exited from the novice transition period mode, where C is between 2 and 10.

[0018] Specifically, the deceleration of the vehicle during driving can be measured by an additionally installed acceleration sensor. When the electric vehicle exits the novice transition mode, the acceleration sensor is no longer needed.

[0019] The principles and beneficial effects of the present invention are introduced below.

[0020] In order to allow novices who are used to driving traditional fuel vehicles to make a good transition to electric vehicles with a coasting energy recovery function, the present invention corrects the correspondence between the accelerator pedal release opening K and the standard motor braking torque M stored before the electric vehicle leaves the factory, and multiplies the standard motor braking torque M by the correction factor f to obtain the actual motor braking torque M', so that the motor brakes with the actual motor braking torque M' to generate electricity and store it in the battery pack. Therefore, the closer the correction factor f is to 1, the greater the coasting energy recovery; conversely, the closer the correction factor f is to 0, the smaller the coasting energy recovery, and the driving experience of releasing the accelerator pedal during the coasting process is approximately close to that of a traditional fuel vehicle.

[0021] When the novice transition mode is just started, the correction factor f is set to the initial value f0 of the correction factor, and then the novice driver is judged whether he can well handle the operation of releasing the accelerator pedal of the electric vehicle according to the actual driving situation: if the driver can well handle the operation, the correction factor f is gradually increased to guide the novice driver to improve the control level of the above operation until the driver completely transitions to the standard coasting energy recovery strength designed by the manufacturer; otherwise, the correction factor f is gradually reduced. The judgment indicator of whether the driver can handle the above operation is the number of over-deceleration events within a fixed time interval: if the number is large, it means that the driver is not familiar with the above operation, cannot control the pedal opening during the process of releasing the accelerator pedal well, and is still inclined to the driving habits of traditional fuel vehicles, and is prone to releasing the accelerator with a large and urgent opening, resulting in excessive deceleration of the vehicle; otherwise, it means that the driver has well learned the operation under the current value of the current correction factor f.

[0022] According to the above principles, it is not difficult to find that the present invention has the following beneficial effects:

[0023] 1. The implementation of the present invention mainly relies on data communication and analysis. On the basis of the existing electric vehicle hardware facilities, it can be realized by only adding an acceleration sensor and related data communication and analysis equipment. The relevant functions can be completed with slight changes on the existing basis, so the operation is simple and the versatility is high.

[0024] 2. When the electric vehicle exits the novice transition mode, the acceleration sensor and related data communication and analysis equipment are no longer needed. These devices can be recycled and reused, so the cost is low.

[0025] 3. The present invention gradually increases or decreases the correction factor f according to the number of over-deceleration events within a fixed time interval, which can well take into account the driving habits of novice drivers and gradually guide them to adapt to the accelerator pedal release operation of electric vehicles. The whole process is automatic and adjusted regularly according to driving conditions, so it is highly reliable and user-friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 Flowchart of an embodiment of the present invention.

[0027] Figure 2 Schematic diagram of the coasting energy recovery system of an electric vehicle in an embodiment of the present invention, in which 1 is the accelerator pedal, 2 is the opening sensor, 3 is the regenerative braking controller, 4 is the motor, 5 is the power converter, 6 is the battery pack, and 7 is the on-board computer. DETAILED DESCRIPTION

[0028] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0029] like Figure 1 and Figure 2 As shown in FIG. 1 , a method for adjusting the coasting energy recovery intensity of an electric vehicle suitable for a novice in the transition period is as follows:

[0030] Before the electric vehicle leaves the factory, the corresponding relationship between the accelerator pedal 1's throttle release opening K and the standard motor braking torque M is stored; when the electric vehicle starts the novice transition mode, the standard motor braking torque M corresponding to the accelerator pedal 1 is found during the driving process according to the accelerator release opening K, and then multiplied by the correction factor f to obtain the actual motor braking torque M′, so that the motor 4 brakes with the actual motor braking torque M′ to generate electrical energy and store it in the battery pack 6, where the correction factor f is between 0 and 1.

[0031] The above-mentioned method for adjusting the coasting energy recovery strength of an electric vehicle applicable to the novice transition period, the value of the correction factor f is determined as follows: the instantaneous correction factor f when the electric vehicle starts the novice transition period mode is taken as the initial value of the correction factor f0; the number of excessive deceleration events and the driving time are recorded during the driving process, wherein the excessive deceleration event refers to an event in which the vehicle deceleration exceeds the critical deceleration value a0 when only the accelerator pedal 1 is released without pressing the brake pedal; at every driving time interval of Δt, the total number of excessive deceleration events N in the time interval is counted and the value of the correction factor f is adjusted:

[0032] (1) If the total number of times N is greater than the critical number of times N0, the value of f-Δf is calculated. If f-Δf>0, the correction factor f is reduced by Δf based on its original value; otherwise, the correction factor f is set to 0;

[0033] (2) If the total number N is equal to the critical number N0, the correction factor f is left unchanged based on its original value;

[0034] (3) If the total number of times N is less than the critical number of times N0, calculate the value of f+Δf. If f+Δf<1, increase the correction factor f by Δf based on its original value; otherwise, set the correction factor f to 1.

[0035] Where Δf is the correction factor change value.

[0036] Furthermore, the initial value f0 of the correction factor is between 0.2 and 0.8.

[0037] Furthermore, the correction factor variation value Δf is between 0.001 and 0.1.

[0038] Furthermore, the critical deceleration value a0 is set at 0.5 m / s 2 Up to 3m / s 2 between.

[0039] Furthermore, the driving time interval Δt is between 0.5 hours and 100 hours, and the critical number of times N0 is between 1 and 500.

[0040] The above-mentioned method for adjusting the coasting energy recovery intensity of an electric vehicle during the novice transition period also includes: if the value of the correction factor f is 1 after C consecutive driving time intervals, the electric vehicle is exited from the novice transition period mode, where C is between 2 and 10.

[0041] Specifically, the deceleration of the vehicle during driving can be measured by an additionally installed acceleration sensor. When the electric vehicle exits the novice transition mode, the acceleration sensor is no longer needed.

[0042] Preferably, the electric vehicle driver's operation log is recorded by the on-board computer 7, and the deceleration during the driving process can be measured and recorded by the accelerometer in the smart phone carried by the driver. By comparing the driver's operating actions recorded by the on-board computer 7 and the deceleration values ​​recorded by the smart phone on the same time axis, the over-deceleration event can be easily determined: if the vehicle's deceleration exceeds the critical deceleration value a0 at a certain moment, and the driver does not step on the brake pedal but releases the accelerator pedal 1 at that moment, it is determined that an over-deceleration event has occurred.

[0043] Specifically, the driver inputs instructions to the on-board computer 7 to enable the electric vehicle to start the novice transition mode, and the value of the correction factor f is set and adjusted by the on-board computer 7 through data analysis.

[0044] Example

[0045] Please refer to Figure 1 and Figure 2. In a certain pure electric vehicle, the accelerator pedal 1's throttle release opening is measured in real time by an opening sensor 2 arranged near the accelerator pedal 1 and the opening result is transmitted to a regenerative braking controller 3 electrically connected thereto. The regenerative braking controller 3 is also electrically connected to a driving computer 7 and a motor 4. The regenerative braking controller 3 stores the relationship between the throttle release opening K and the standard motor torque M and the value of the correction factor f in a table. The driving computer 7 records all driving behaviors of the vehicle and can periodically send instructions to the regenerative braking controller 3 to modify the value of the correction factor f. The motor 4 is electrically connected to the battery pack 6 via a power converter 5. The power converter 5 is used for AC / DC and voltage conversion of current between the motor 4 and the battery pack 6.

[0046] In this embodiment, the values ​​of the initial value f0 of the correction factor, the change value Δf of the correction factor, the critical deceleration value a0, the driving time interval Δt, the critical number of times N0 and the number of times C are 0.3, 0.05 and 1 m / s respectively. 2 , 1 hour, 10 and 3.

[0047] One day, a driver with many years of experience in driving traditional fuel vehicles transformed into a "novice" driver of the electric vehicle. The driver input a command to the driving computer 7 to start the novice transition mode, and then the correction factor f was set to 0.3. After the driver drove for 1 hour, because the vehicle only had 5 excessive deceleration events within 1 hour, which was less than the critical number N0, the driving computer 7 increased the correction factor f by 0.05 and sent the new correction factor f value of 0.35 to the regenerative braking controller 3. Similarly, under the premise of ensuring that the value of the correction factor f is between 0 and 1, for every 1 hour of driving, if the vehicle deceleration transition events in this time period are greater than 10, the correction factor is reduced by 0.05 based on its original value; if it is equal to 10, the correction factor f is kept unchanged based on its original value; if it is less than 10, the correction factor f is increased by 0.05 based on its original value.

[0048] After a period of driving, the value of the correction factor f continues to increase until it is 1 for three consecutive judgments. At this time, it means that the driver is able to release the accelerator pedal 1 during the coasting process. Therefore, the on-board computer 7 automatically ends the novice transition mode, and the regenerative braking controller 3 controls the braking torque of the motor 4 according to the relationship between the accelerator opening K and the standard motor braking torque M stored in a table before leaving the factory, without correcting the braking torque.

[0049] In the embodiment of the present invention, the adjustment of the coasting energy recovery force mainly relies on data communication and analysis. On the basis of the existing electric vehicle hardware facilities, it can be realized by only adding an acceleration sensor and related data communication and analysis equipment. The relevant functions can be completed with slight modifications on the existing basis, so the operation is simple and the versatility is high; when the electric vehicle exits the novice transition mode, the acceleration sensor and related data communication and analysis equipment are no longer needed. These devices can be recycled and reused, so the cost is low; in this embodiment, the correction factor f is gradually increased or decreased according to the number of excessive deceleration events within a fixed time interval, which can well take into account the driving habits of novice drivers and gradually guide novices to adapt to the accelerator pedal release 1 operation of the electric vehicle. The whole process is automatic and adjusted regularly according to the driving conditions, so it is highly reliable and user-friendly.

Claims

1. A method for adjusting the coasting energy recovery strength of an electric vehicle suitable for a novice transition period, characterized in that: The corresponding relationship between the accelerator pedal release opening K and the standard motor braking torque M is stored before the electric vehicle leaves the factory; when the electric vehicle starts the novice transition mode, the standard motor braking torque M corresponding to the accelerator pedal release opening K is checked during the driving process, and then multiplied by the correction factor f to obtain the actual motor braking torque M′, so that the motor is braked with the actual motor braking torque M′ to generate electrical energy and store it in the battery pack, wherein the correction factor f is between 0 and 1; The value of the correction factor f is determined as follows: the instantaneous correction factor f in the transition period mode of the novice when the electric vehicle is started is taken as the initial value of the correction factor f0; the number of excessive deceleration events and the driving time are recorded during the driving process, wherein the excessive deceleration event refers to the event that the vehicle deceleration exceeds the critical deceleration value a0 when the accelerator pedal is only released without pressing the brake pedal; every driving time interval of Δt, the total number of excessive deceleration events N in the time interval is counted and the value of the correction factor f is adjusted: (1) If the total number of times N is greater than the critical number of times N0, the value of f-Δf is calculated. If f-Δf>0, the correction factor f is reduced by Δf based on its original value; otherwise, the correction factor f is set to 0; (2) If the total number N is equal to the critical number N0, the correction factor f is left unchanged based on its original value; (3) If the total number of times N is less than the critical number of times N0, the value of f+Δf is calculated. If f+Δf<1, the correction factor f is increased by Δf based on its original value. Otherwise, let the correction factor f be 1; Where Δf is the correction factor change value.

2. The method for adjusting the coasting energy recovery strength of an electric vehicle suitable for a novice transition period as claimed in claim 1 is characterized in that: The initial value f0 of the correction factor is between 0.2 and 0.

8.

3. The method for adjusting the coasting energy recovery strength of an electric vehicle suitable for a novice transition period as claimed in claim 1 is characterized in that: The correction factor variation value Δf is between 0.001 and 0.

1.

4. The method for adjusting the coasting energy recovery strength of an electric vehicle suitable for a novice transition period as claimed in claim 1 is characterized in that: The critical deceleration value a0 is 0.5m / s 2 Up to 3m / s 2 between.

5. The method for adjusting the coasting energy recovery strength of an electric vehicle suitable for a novice transition period as claimed in claim 1 is characterized in that: The driving time interval Δt is between 0.5 hours and 100 hours, and the critical number N0 is between 1 and 500.

6. The method for adjusting the coasting energy recovery strength of an electric vehicle suitable for a novice transition period as claimed in claim 1 is characterized in that: If the correction factor f takes the value of 1 after C consecutive driving time intervals, where C is between 2 and 10, the electric vehicle will exit the novice transition mode.

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