CN112776666B - Energy recovery method of extended range electric vehicle based on sliding state - Google Patents

Abstract

The invention discloses an extended range electric vehicle energy recovery method based on a sliding state, which selects the charging time of a battery and intervenes the charging speed of the battery through a sliding duty ratio Q, wherein the sliding duty ratio Q is the share of the time of the vehicle in the sliding state per minute; the controller monitors the action of the accelerator pedal in real time, when the accelerator pedal is in an initial position, the automobile is taken as an automobile sliding state, and when the accelerator pedal is not in the initial position, the automobile is taken as a driving state, and the automobile is driven by the motor to run. According to the extended-range electric automobile energy recovery method based on the sliding state, when the controller executes the energy recovery action, the kinetic energy of the automobile is immediately recovered, the wheel anti-dragging motor is enabled to generate power, corresponding braking force is generated on the wheel, and after a driver does not need to step on a brake pedal, the kinetic energy of the automobile is recovered, the wheel anti-dragging motor is enabled to generate power, and corresponding braking force is generated on the wheel.

Description

Energy recovery method of extended-range electric vehicle based on coasting state

technical field

The invention belongs to an energy recovery method for an extended-range electric vehicle based on a gliding state.

Background technique

Most of the braking energy recovery or engine start-up charging in the prior art only considers factors such as battery SOC value and charging efficiency, but does not consider the driving conditions of the car. Toggles between drive mode and coast mode; however, the car coast mode is used less frequently when the car is driving on clear, flat surfaces. The frequent coasting process of the car is just the best opportunity for energy recovery or battery replenishment. When coasting, the driver needs to properly control the speed of the vehicle to slow down the car, and use a stronger energy recovery gear to generate stronger braking force, so that Control the speed of the vehicle and regenerate energy. When the taxiing frequency of the car is low, the speed fluctuation of the car is smaller. At this time, the driver pays more attention to the driving smoothness during the taxiing process, so the energy recovery intensity should be weaker, so as to prevent the drastic change of the vehicle speed and affect the driving smoothness.

SUMMARY OF THE INVENTION

In order to solve the defect in the prior art that the braking energy recovery or engine start-up charging does not consider the driving conditions of the vehicle, the present invention provides an energy recovery method for an extended-range electric vehicle based on a coasting state.

In the present invention, the coasting duty ratio Q is used as the judgment standard of the coasting frequency, which is defined as the percentage of the time that the vehicle is in the coasting state per minute. The controller monitors the action of the accelerator pedal in real time. When the accelerator pedal is in the initial position, it is identified as the vehicle coasting state, and the coasting state includes the process of the driver stepping on the brake pedal to brake. When the accelerator pedal is not in the initial position as the driving state, the car is driven by the motor to drive. The controller uses minutes as the basic metering time period to calculate the duty cycle of its coasting in real time. When the car is coasting, the controller can put the car into an energy recovery state, that is, drive the generator through the wheels to charge the battery and generate braking force.

In the present invention, in addition to the SOC index, a new reference index-battery power change rate R is added, which is defined as the change value (percentage) of the battery SOC per minute. When the battery power increases, R is a positive value, and the battery power When falling, R is negative. Through this indicator, the charging and discharging speed of the battery can be accurately monitored under the temperature of different seasons, and the charging and discharging speed of the battery can be monitored under different driving conditions or loads of the vehicle, so as to know the charging and discharging status of the battery in time, and select in advance. The charging timing of the battery and the charging speed of the battery are intervened instead of waiting for the SOC in the battery to be too low.

The intensity of energy recovery is 1st, 2nd and 3rd in order from low to high. Among them, the recovery intensity of the 1st gear is 25% of the maximum energy recovery intensity of the vehicle, and the recovery intensity of the 2nd gear is 25% of the maximum energy recovery intensity of the vehicle. 50%, the recovery intensity of 3rd gear is the maximum energy recovery intensity of the car.

After the engine is started, the matching generator is driven with the set power to generate electricity to supplement the car battery.

The control process of the present invention comprises the following steps:

S1. The controller for energy distribution is started;

S2, the controller judges the sliding state of the car;

S3. (1) If the car is in a coasting state and the coasting duty ratio Q<20%, it is determined that the car is in a coasting state with a low coasting frequency; using the battery module that monitors the battery voltage and current, the controller determines the value of the battery SOC ;

1) If 30%≤SOC<50%, it indicates that the remaining power in the battery is relatively sufficient, then enter the first gear with the lowest energy recovery intensity. At this time, the braking force generated by the energy recovery is the weakest, and the controller detects and judges the change of battery power. The rate R is the rate of change of battery power. If R>0, it means that the energy generated by the first level of energy recovery is enough to supply power to the battery, and the first level of energy recovery is maintained to continue to recover the kinetic energy of the car; if R≤0, it means that the energy generated by the first level of energy recovery If there is not enough power to recharge the battery, the energy recovery is adjusted to 2nd gear in order to generate stronger braking force and recover more energy.

2) If SOC<30%, it means that the remaining power in the battery is insufficient, then enter the second stage of energy recovery, the controller detects and judges the battery power change rate R, if R>0, it means that the power generated in the second stage of energy recovery is enough to replenish the battery. If R ≤ 0, it means that the power generated by the 2nd gear of energy recovery alone is not enough to recharge the battery, then the engine starts and drives the generator at the same time. Recharge the battery.

3) If the SOC is greater than or equal to 50%, it indicates that the remaining power in the battery is sufficient, and the controller does not act.

(2) If the car is in a coasting state, and the coasting duty ratio Q≥20%, it is determined that the car is in a high coasting frequency state; using the battery module that monitors the battery voltage and current, the controller determines the value of the battery SOC;

1) If 30%≤SOC<50%, it means that the remaining power in the battery is relatively sufficient, then enter the second stage of energy recovery, the controller detects and judges the battery power change rate R, if R>0, it means that the second stage of energy recovery generates electricity If it is enough to recharge the battery, keep the 2nd gear of energy recovery, so as to continue to recover the kinetic energy of the car and recharge the battery; if R≤0, it means that the power generated by the 2nd gear of energy recovery is not enough to recharge the battery, then the energy recovery is adjusted to 3 gears in order to generate stronger braking power and recover more energy.

2) If SOC<30%, it means that the remaining power in the battery is insufficient, then enter the third gear of energy recovery, the controller detects and judges the rate of change of battery power R, if R>0, it means that the third gear of energy recovery produces enough power to replenish the battery. If R ≤ 0, it means that the power generated only by the 3rd gear of energy recovery is not enough to recharge the battery, then the engine starts and drives the generator at the same time. Recharge the battery.

3) If the SOC is greater than or equal to 50%, it indicates that the remaining power in the battery is sufficient, and the controller does not act.

S4. After the last execution action in the above S3 starts, the state is maintained for a certain period of time, so as to reserve enough working time for the above execution action. Preferably, the holding time is 10 minutes.

The hardware in the present invention at least includes: a controller, a battery module capable of monitoring the performance of the battery, a motor capable of driving the wheels and generating electricity from the back drag of the wheels, a generator and an engine. The controller connects with the battery module, motor, generator and engine and controls their operation.

Beneficial effect: The method for recovering the energy of the extended-range electric vehicle based on the coasting state of the present invention, when the controller executes the energy recovery action, immediately recovers the kinetic energy of the vehicle, makes the wheel anti-drag motor generate electricity, and generates corresponding braking on the wheels. It does not need to wait for the driver to step on the brake pedal before recovering the kinetic energy of the car, making the wheel anti-drag motor generate electricity, and generating corresponding braking force on the wheels.

Description of drawings

The accompanying drawings are used to provide a further understanding of the present invention, and constitute a part of the specification, and are used to explain the present invention together with the embodiments of the present invention, and do not constitute a limitation to the present invention. In the attached image:

FIG. 1 is a flow chart of the present invention.

Detailed ways

The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, but not to limit the present invention.

Example

As shown in Fig. 1, an energy recovery method for extended-range electric vehicles based on coasting state, the control process includes the following steps:

S1. The controller for energy distribution is started;

S2, the controller judges the sliding state of the car;

S3. (1) If the car is in a coasting state and the coasting duty ratio Q<20%, it is determined that the car is in a coasting state with a low coasting frequency, and the control logic at this time is mainly based on driving smoothness to avoid energy recovery. The impact of large braking force on ride comfort; the controller judges the value of the battery SOC by using the battery module that monitors the battery voltage and current;

1) If 30%≤SOC<50%, it indicates that the remaining power in the battery is relatively sufficient, then enter the first gear with the lowest energy recovery intensity. At this time, the braking force generated by the energy recovery is the weakest, and the controller detects and judges the change of battery power. The rate R is the rate of change of battery power. If R>0, it means that the energy generated by the first level of energy recovery is enough to supply power to the battery, and the first level of energy recovery is maintained to continue to recover the kinetic energy of the car; if R≤0, it means that the energy generated by the first level of energy recovery If there is not enough power to recharge the battery, the energy recovery is adjusted to 2nd gear in order to generate stronger braking force and recover more energy.

2) If SOC<30%, it means that the remaining power in the battery is insufficient, then enter the second stage of energy recovery, the controller detects and judges the battery power change rate R, if R>0, it means that the power generated in the second stage of energy recovery is enough to replenish the battery. If R ≤ 0, it means that the power generated by the 2nd gear of energy recovery alone is not enough to recharge the battery, then the engine starts and drives the generator at the same time. Recharge the battery.

3) If the SOC is greater than or equal to 50%, it indicates that the remaining power in the battery is sufficient, and the controller does not act.

(2) If the car is in a coasting state and the coasting duty ratio Q≥20%, it is determined that the car is in a high coasting frequency state; the control logic at this time is mainly energy recovery, making full use of the coasting state of the car to recover kinetic energy, Avoid low battery power and affect the driving mileage of the car, and it is consistent with the driver's desire to control or limit the speed of the vehicle at this time, using the battery module that monitors the battery voltage and current, the controller determines the value of the battery SOC;

1) If 30%≤SOC<50%, it means that the remaining power in the battery is relatively sufficient, then enter the second stage of energy recovery, the controller detects and judges the battery power change rate R, if R>0, it means that the second stage of energy recovery generates electricity If it is enough to recharge the battery, keep the 2nd gear of energy recovery, so as to continue to recover the kinetic energy of the car and recharge the battery; if R≤0, it means that the power generated by the 2nd gear of energy recovery is not enough to recharge the battery, then the energy recovery is adjusted to 3 gears in order to generate stronger braking power and recover more energy.

2) If SOC<30%, it means that the remaining power in the battery is insufficient, then enter the third gear of energy recovery, the controller detects and judges the rate of change of battery power R, if R>0, it means that the third gear of energy recovery produces enough power to replenish the battery. If R ≤ 0, it means that the power generated only by the 3rd gear of energy recovery is not enough to recharge the battery, then the engine starts and drives the generator at the same time. Recharge the battery.

3) If the SOC is greater than or equal to 50%, it indicates that the remaining power in the battery is sufficient, and the controller does not act.

S4. After the last execution action in the above S3 starts, the state is maintained for a certain period of time, so as to reserve enough working time for the above execution action. Preferably, the holding time is 10 minutes.

In the energy recovery of the present invention, when the controller executes the energy recovery action, the vehicle kinetic energy can be recovered immediately, the wheel anti-drag motor can be generated, and the corresponding braking force can be generated on the wheels.

Finally, it should be noted that the above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, for those skilled in the art, the The technical solutions described in the foregoing embodiments may be modified, or some technical features thereof may be equivalently replaced. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims (5)

1. The extended-range electric vehicle energy recovery method based on the coasting state is characterized in that the charging time of a battery is selected and the charging speed of the battery is intervened through a coasting duty ratio Q, wherein the coasting duty ratio Q is the percentage of the time of the vehicle in the coasting state per minute; the controller monitors the action of the accelerator pedal in real time, when the state that the accelerator pedal is at the initial position is identified as the automobile sliding state, and when the state that the accelerator pedal is not at the initial position is taken as the driving state, the automobile is driven by the motor to run; accurately monitoring the charging and discharging speed of the battery by adopting the change value of the SOC of the battery per minute, namely the change rate R of the electric quantity of the battery, selecting the charging time of the battery in advance and intervening the charging speed of the battery; when the electric quantity of the battery is increased, R is a positive value, and when the electric quantity of the battery is decreased, R is a negative value; in addition, the extended range electric vehicle energy recovery method based on the sliding state comprises the following specific steps:

s1, starting a controller for energy distribution;

s2, judging the automobile sliding state by the controller;

s3: s31, if the automobile is in a sliding state and the sliding duty ratio Q is less than 20%, judging that the automobile is in a sliding state with low sliding frequency, and judging the value of the SOC of the battery by using a battery module for monitoring the voltage and the current of the battery through a controller;

s311, if the SOC is more than or equal to 30% and less than 50%, entering an energy recovery intensity 1 gear, detecting and judging the electric quantity change rate R of the battery by the controller, and if R is more than 0, keeping the energy recovery 1 gear so as to continuously recover the kinetic energy of the automobile; if R is less than or equal to 0, the energy recovery is adjusted to 2 grades;

s312, if the SOC is less than 30%, entering an energy recovery 2 gear, detecting and judging the change rate R of the electric quantity of the battery by the controller, and if the R is greater than 0, keeping the energy recovery 2 gear; if R is less than or equal to 0, the engine is started and drives the generator to supplement power to the battery;

s313, if the SOC is more than or equal to 50 percent, indicating that the residual electric quantity in the battery is sufficient, the controller does not act;

s32, if the automobile is in a sliding state and the sliding duty ratio Q is more than or equal to 20%, judging that the automobile is in a high sliding frequency state; the controller judges the value of the SOC of the battery by utilizing a battery module for monitoring the voltage and the current of the battery;

s321, if the SOC is more than or equal to 30% and less than 50%, entering an energy recovery 2-gear, detecting the electric quantity change rate R of the battery by using a controller, and if R is more than 0, keeping the energy recovery 2-gear so as to continuously recover the kinetic energy of the automobile and supplement the electricity to the battery; if R is less than or equal to 0, adjusting the energy recovery to 3 grades;

s322, if the SOC is less than 30%, entering an energy recovery 3-gear, detecting and judging the change rate R of the battery electric quantity by the controller, and if the R is greater than 0, keeping the energy recovery 3-gear; if R is less than or equal to 0, the electric quantity generated by the energy recovery gear 3 is not enough to supplement the electricity to the battery, and the engine is started and drives the generator to supplement the electricity to the battery;

s323, if the SOC is more than or equal to 50 percent, the residual electric quantity in the battery is sufficient, the controller does not act;

after the last execution action in S4, S311, S312, S321, or S322 is started, the execution state of the execution action is maintained for a certain time to reserve enough working time for the execution action, and then the process returns to S2 to loop again.

2. The energy recovery method for the extended-range electric vehicle based on the coasting condition of claim 1, wherein the controller calculates the coasting duty cycle in real time with minutes as a basic metering time period; when the automobile is in a sliding state, the controller enables the automobile to enter an energy recovery state, and the wheels drive the generator to charge the battery and generate braking force.

3. The energy recovery method for the extended range electric vehicle based on the coasting condition of claim 1, wherein the energy recovery intensity is sequentially from low to high in the 1 st gear, the 2 nd gear and the 3 rd gear, wherein the recovery intensity of the 1 st gear is 25% of the maximum energy recovery intensity of the vehicle, the recovery intensity of the 2 nd gear is 50% of the maximum energy recovery intensity of the vehicle, and the recovery intensity of the 3 rd gear is the maximum energy recovery intensity of the vehicle; after the engine is started, the matched generator is driven by the set power to generate electricity, and electricity is supplemented for the automobile battery.

4. The energy recovery method of claim 1, wherein the coasting state includes braking when the driver steps on the brake pedal.

5. The energy recovery method of claim 1, wherein the step of maintaining the execution state of the execution operation for 10 minutes in S4 is further included.

Images