CN113147425A

CN113147425A - Method for recovering multi-gear new energy vehicle in sliding process

Info

Publication number: CN113147425A
Application number: CN202110430889.7A
Authority: CN
Inventors: 李刚; 张双军; 董翔宇; 郑士卓; 马小康
Original assignee: BAIC Motor Co Ltd
Current assignee: BAIC Motor Co Ltd
Priority date: 2021-04-21
Filing date: 2021-04-21
Publication date: 2021-07-23

Abstract

The embodiment of the invention discloses a method for recovering a multi-gear new energy vehicle in a sliding process, which comprises the following steps: setting the vehicle sliding energy recovery as a multilevel recovery intensity, and constructing a basic recovery torque chart based on the multilevel recovery intensity and the vehicle running state; obtaining a basic recovery torque in the constructed basic recovery torque map based on the acquired vehicle running state; obtaining a sliding moment and a motor speed ratio based on the basic recovery torque, the obtained vehicle running road condition and the obtained mechanical control state of the vehicle; obtaining a motor target torque based on the sliding torque and the motor speed ratio; recovering recovered energy of the vehicle coasting process based on the target torque. The purpose of avoiding the interruption of the recovery torque is achieved.

Description

Method for recovering multi-gear new energy vehicle in sliding process

Technical Field

The invention belongs to the technical field of new energy vehicles, and particularly relates to a method for recovering a sliding process of a multi-gear new energy vehicle.

Background

The new energy vehicle comprises: including electric-only vehicles and hybrid vehicles. The new energy vehicle adopts the motor to generate negative torque to realize braking energy recovery, as shown in fig. 1, the recovery process comprises the following steps: coast recovery and brake recovery. The energy recovery in the sliding process means that when a driver looses an accelerator in the running process of the vehicle, the torque of a motor is converted from positive torque to negative torque, and the energy recovery is carried out; the energy recovery in the braking process means that a driver steps on a brake pedal, the torque of a motor is converted from positive torque to negative torque, and the energy recovery is carried out. The endurance mileage of more than 20 percent and the oil saving rate of more than 15 percent can be realized through energy recovery; the sliding recovery can enable a user to obtain the driving convenience and the new driving pleasure of the vehicle operated by a single pedal, meanwhile, the intervention of mechanical braking is further reduced, and the regeneration recovery rate of actual driving is obviously improved, so that most vehicles adopt 3-level or even 5-level sliding recovery adjustment.

New energy vehicles, particularly hybrid vehicles, often adopt a multi-gear design, such as 2-gear electric vehicles, hybrid vehicles adopting DCT (motor in intermediate shaft) or AMT, and the like, and during the motor shifting process, there is often a phenomenon of power interruption, so that the interruption feeling is reduced by adopting a mode (hybrid) of increasing the shifting vehicle speed or supplementing torque to the engine; however, in the coasting recovery process, the motor is required to downshift, so that the downshift vehicle speed is low, the user sensitivity is high, and the engine torque cannot be compensated.

Therefore, in the prior art, most vehicles adopt a user-adjustable mode, the recovery grade is adjusted in a gear lever, a shifting sheet or a large screen, and a user manually adjusts the recovery grade according to needs; meanwhile, the new energy vehicle with multiple gears cannot adopt large sliding torque recovery. In the prior art, a user manually adjusts the sliding recovery strength according to the road condition and the gear, the recovery strength needs to be manually increased by a driver under the working condition of downhill, and the requirement on the driver is high due to the fact that the recovery strength is manually adjusted according to the distance at a traffic light intersection, so that most users generally only use the default gear, and a good energy-saving effect is difficult to obtain. Meanwhile, if the recovery torque value is large, as shown in fig. 2, the problems of loss of deceleration sense, forward rush, jerk and the like caused by interruption of negative torque of a motor in the gear shifting process need to be avoided, so that the comprehensive improvement of high recovery rate, single-pedal driving pleasure and riding perception is difficult to achieve in the sliding recovery of the multi-gear vehicle.

Disclosure of Invention

In view of this, the embodiment of the invention provides a method for recovering a sliding process of a multi-gear new energy vehicle, which at least solves the problem of interruption of recovered torque in manual adjustment in the prior art.

The embodiment of the invention provides a method for recovering a multi-gear new energy vehicle in a sliding process, which comprises the following steps:

setting the vehicle sliding energy recovery as a multilevel recovery intensity, and constructing a basic recovery torque chart based on the multilevel recovery intensity and the vehicle running state;

obtaining a basic recovery torque in the constructed basic recovery torque map based on the acquired vehicle running state;

obtaining a sliding moment and a motor speed ratio based on the basic recovery torque, the obtained vehicle running road condition and the obtained mechanical control state of the vehicle;

obtaining a motor target torque based on the sliding torque and the motor speed ratio;

recovering recovered energy of the vehicle coasting process based on the target torque.

Optionally, the vehicle sliding energy recovery is set as a three-level recovery intensity, which is a first-level recovery intensity, a second-level recovery intensity and a third-level recovery intensity,

the primary recovery strength is set according to the dragging and decelerating of the simulated engine, and the dragging and decelerating of the simulated engine is weaker than the dragging and decelerating of the engine;

setting the three-level recovery strength according to the capacity boundary of the electric drive system and the condition which is allowed to be accepted by the adjustment and calibration of the brake system, and considering the ESP safety and the brake torque curve corresponding to the Iboost push rod;

and the secondary recovery strength is set according to the difference between the primary recovery strength and the tertiary recovery strength.

Optionally, the vehicle operation state includes a throttle state and a vehicle speed of the vehicle.

Optionally, the vehicle running road conditions include a road gradient and a vehicle sliding distance;

and the mechanical control state of the vehicle comprises a vehicle gear and vehicle braking.

Optionally, obtaining a slip torque and a motor speed ratio based on the basic recovered torque, the obtained vehicle operation road condition, and the mechanical control state of the vehicle includes:

according to the road slope, gain compensation is carried out on basic recovery torque, and the method specifically comprises the following steps:

and (4) defining grade of the ramp according to the gradient size, and setting a gain compensation coefficient according to the grade of the ramp.

Optionally, the step of defining a grade of the slope according to the magnitude of the slope, and setting a gain compensation coefficient according to the grade of the slope includes:

comparing the road gradient with the set values a1, a2, and A3;

if the gain is smaller than A1, the grade is a small slope grade, and the gain compensation coefficient is 1.1-1.2;

if the gain is greater than or equal to A1 and less than A2, the grade is a middle slope grade, and the gain compensation coefficient is 1.2-1.4;

if the grade is greater than or equal to A2 and less than A3, the gain compensation coefficient is 1.5.

and carrying out gain compensation on the basic recovery torque according to the vehicle sliding distance.

Optionally, the performing gain compensation on the basic recovered torque according to the vehicle sliding distance includes:

judging the difference of the sliding distance of the vehicle based on the position of the vehicle and the map information;

when the vehicle is judged to slide for a long time based on the sliding distance difference of the vehicle, the gain compensation coefficient is 0.7-0.8;

when the vehicle is judged to slide normally based on the sliding distance difference of the vehicle, the gain compensation coefficient is 1;

when it is determined to increase the braking based on the difference in the coasting distance of the vehicle, the gain compensation coefficient is 1.2 to 1.3.

judging the sliding gear of the vehicle, and attenuating the torque value when the vehicle is in a high gear, wherein the attenuation coefficient is 0.7-1, and the attenuation is larger when the vehicle is closer to a gear shifting area;

and when the accelerator of the vehicle is changed by more than 30% or the stroke of the brake pedal is more than 30% and the duration time is 1s, gradually carrying out RAMP transition on the torque of the low gear.

when the vehicle is braked, the sliding torque is reduced according to the stroke of a brake pedal;

and/or the presence of a gas in the gas,

when the vehicle is equipped with the self-adaptation and patrols and navigates, gain compensation is carried out on the sliding energy recovery according to the position of the front vehicle and the current speed at the moment of accelerator loosening.

According to the invention, the basic recovery torque is obtained according to the vehicle running state, and then on the basic layer of the basic recovery torque, the sliding torque and the motor speed ratio are obtained based on the vehicle running road condition and the mechanical control state of the vehicle, so that the motor target torque is obtained. The aim of avoiding the interruption of the recovery torque is achieved by automatically adjusting the target torque of the motor.

From whole car angle, comprehensive consideration ramp, road conditions information and gear, carry out the optimal computation to basic retrieval moment of torsion, give clear and definite control logic and gain algorithm under the multi-information complex condition, accord with the engineering requirement, the robustness is high, and the expansibility is strong, can be according to motorcycle type characteristic and configuration, selects whole or partial function. The energy is fully recovered, the operation of a user is reduced, the problem of drivability caused by repeated change of braking torque calculated by pure theory is avoided, and the problem of interruption of the recovered torque at the gear shifting moment is reduced.

Additional features and advantages of the invention will be set forth in the detailed description which follows.

Drawings

The above and other objects, features and advantages of the present invention will become more apparent by describing in more detail exemplary embodiments thereof with reference to the attached drawings, in which like reference numerals generally represent like parts throughout.

FIG. 1 illustrates a schematic diagram of regenerative braking energy recovery in the prior art;

FIG. 2 is a schematic diagram showing various levels of coast recovery torque in the prior art;

FIG. 3 is a schematic diagram illustrating a multi-gear energy-new vehicle coasting process recovery method according to an embodiment of the invention;

FIG. 4 shows a schematic of a base recovery torque graph of one embodiment of the present invention;

FIG. 5 illustrates a schematic of the different gear coast recovery damping of an embodiment of the present invention;

FIG. 6 illustrates a different brake travel coast recovery decay map for an embodiment of the present invention;

wherein, 1-a drive shaft; 2-a gearbox; 3, an engine; 4-a motor; 5-battery pack.

Detailed Description

Preferred embodiments of the present invention will be described in more detail below. While the following describes preferred embodiments of the present invention, it should be understood that the present invention may be embodied in various forms and should not be limited by the embodiments set forth herein.

iBooster is a vehicle braking technology.

A method for recovering a multi-gear new energy vehicle in a sliding process comprises the following steps:

the simulated engine drag deceleration is slightly weaker than the engine drag deceleration.

The gradient of the road can be obtained from historical data or data stored in a cloud.

comparing the road gradient with the set values a1, a2, and A3;

namely, when the vehicle reaches the intersection and the throttle baffle is loosened, the sliding distance can be obtained according to the vehicle speed and the map information.

and/or the presence of a gas in the gas,

In a particular application scenario,

and determining the required deceleration of the vehicle according to the vehicle speed by the aid of the sliding energy recovery, and setting the magnitude of the negative torque at the wheel end. And the calculation is carried out and the energy recovery limit value which can be born by an electric drive system (a battery, a motor and the like) is referred, so that the efficient and comfortable sliding energy recovery driving feeling is ensured. Setting 2-3 recovery intensities for the sliding energy recovery aiming at the actual situation of vehicle type development and positioning so as to support a driver to select the favorite driving habit; the following is an example of the basic recovery of the three-stage recovery: the first-level setting simulates the dragging and decelerating of an engine and is slightly weaker than the dragging and decelerating of the engine; the three-level comprehensive design (considering the ESP safety and a braking torque curve corresponding to an Iboost push rod) is generally designed to be about 0.1g of braking deceleration according to conditions such as the capability boundary of an electric drive system, the allowable conditions of the adjustment and the calibration of a braking system, and the like, and is properly calibrated and optimized according to the actual driving perception; the second level of coast recovery will be set by the difference between the first level and the third level.

As shown in fig. 3 and 4, after the basic torque calculation is completed, optimization and correction are performed based on the basic torque MAP in consideration of the hill, the difference in the parking distance, the shift correction, and the braking force correction.

According to the method, gain compensation is carried out on the basic value of the sliding energy recovery under the working condition of downhill, and more energy can be recovered when a driver does not tread on the brake. According to the gradient signal, the downhill working condition is divided into a small slope, a medium slope and a large slope.

When the vehicle is in a continuously running state, that is, the vehicle speed is greater than a certain value and the running time is sufficient, the vehicle makes a hill-run determination. When the gradient is less than a certain value A1, the condition is considered as a small-gradient condition, when the gradient is between A1 and A2, the condition is considered as a medium-gradient condition, and when the gradient is between A2 and A3, the condition is considered as a large-gradient condition. And (3) calculating three compensation coefficients k1 according to the ramp condition respectively, and gaining basic recovery torque, wherein specific values need real vehicle calibration.

TABLE 1 slope correction factor

Slope of slope	Ramp grade confirmation	Recommending a range of gain coefficients
			＜A1	Small slope working condition	1.1-1.2
A1-A2	Medium slope working condition	1.2-1.4
			A2-A3	Heavy slope working condition	1.5

For a vehicle with an ACC (adaptive cruise control), gain compensation is carried out on the sliding energy recovery according to the positions of the vehicle before entering a traffic light intersection and the vehicle in front of the traffic light intersection, so that more energy can be recovered when a driver does not step on the brake, and the probability of the user on the brake is reduced. According to the situation of the front vehicle position, the downhill working condition is divided into prolonged sliding, normal sliding and increased braking.

According to the high-precision map information, when the vehicle is about to enter the intersection, namely the vehicle speed is greater than a certain value, the running time is enough, and the vehicle performs the sliding distance difference judgment.

△D＝D1-D2＝D1-V²/a；

V is the tip-out corresponding vehicle speed a is the acceleration calculated for the current base creep torque, and D1, D2, and D3 are distance values.

When the distance difference Δ D is less than a predetermined value D1, it is considered to be a prolonged coasting, when the distance difference is between D1 and D2, it is considered to be a normal coasting, and when the distance difference is between D2 and D3, it is considered to increase braking. And (3) calculating three compensation coefficients k2 according to the distance condition respectively, and gaining basic recovery torque, wherein specific values need real vehicle calibration.

TABLE 2 parking Difference correction factor

For a vehicle with an ACC (adaptive cruise control), gain compensation can be performed on the sliding energy recovery according to the position of a front vehicle and the current vehicle speed at the moment that a driver releases an accelerator, so that more energy can be recovered when the driver does not tread on the brake, and the probability that the user treads on the brake is reduced.

And correcting the basic value of the sliding torque according to different gears. The problem of power interruption of multiple gears during gear shifting is considered. The torque value is thus damped in the high gear, with a damping factor of 0.7-1, the value being damped the greater the closer it is to the shifting region, as shown in fig. 5.

In order to avoid the problem of inconsistent coasting recovery perception caused by single-driving gear shifting, a single-driving behavior locking strategy is provided, and after the low gear is replaced, the condition that the accelerator change is more than 30% or the brake pedal stroke is more than 30% and the duration is 1s is met, the RAMP transition is gradually carried out on the torque of the low gear.

When braking is stepped on, according to the stroke of a driver for stepping on a brake pedal, the sliding torque is reduced, the sliding torque is smaller in the gear shifting process of a motor shaft, and the condition that deceleration is lost due to torque clearing of the motor during gear shifting is reduced, as shown in fig. 6. The optimal motor recovery effect is ensured to be achieved in the braking process, and meanwhile, the braking feeling of a driver is ensured.

Having described embodiments of the present invention, the foregoing description is intended to be exemplary, not exhaustive, and not limited to the embodiments disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A method for recovering a multi-gear new energy vehicle in a sliding process is characterized by comprising the following steps:

2. The method for recycling a coasting procedure of a multi-gear new energy vehicle according to claim 1, wherein the vehicle coasting energy recycling is set to three levels of recycling strength, i.e., a primary recycling strength, a secondary recycling strength and a tertiary recycling strength,

3. The method for recovering the coasting process of the multi-gear new energy vehicle according to claim 1, wherein the vehicle running states comprise a throttle state and a vehicle speed of the vehicle.

4. The method for recycling the coasting process of the multi-gear new energy vehicle according to claim 1, wherein the vehicle runs according to road conditions including a road gradient and a vehicle coasting distance;

5. The method for recovering the coasting process of the multi-gear new energy vehicle according to claim 4, wherein the obtaining of the slip torque and the motor speed ratio based on the basic recovered torque, the obtained vehicle running road condition and the vehicle mechanical control state comprises:

6. The method for recovering the coasting process of the multi-gear new energy vehicle according to claim 5, wherein the step of defining the grade according to the gradient size and the step of setting the gain compensation coefficient according to the grade comprises the following steps:

comparing the road gradient with the set values a1, a2, and A3;

7. The method for recovering the coasting process of the multi-gear new energy vehicle according to claim 4, wherein the obtaining of the slip torque and the motor speed ratio based on the basic recovered torque, the obtained vehicle running road condition and the vehicle mechanical control state comprises:

8. The method for recovering the coasting process of the multi-gear new energy vehicle according to claim 7, wherein the gain compensation of the basic recovered torque according to the vehicle coasting distance comprises:

9. The method for recovering the coasting process of the multi-gear new energy vehicle according to claim 4, wherein the obtaining of the slip torque and the motor speed ratio based on the basic recovered torque, the obtained vehicle running road condition and the vehicle mechanical control state comprises:

10. The method for recovering the coasting process of the multi-gear new energy vehicle according to claim 4, wherein the obtaining of the slip torque and the motor speed ratio based on the basic recovered torque, the obtained vehicle running road condition and the vehicle mechanical control state comprises:

and/or the presence of a gas in the gas,