CN104442767A - Hydraulic braking system having energy feedback and ESP functions and control method of hydraulic braking system - Google Patents

Abstract

The invention relates to a hydraulic braking system having energy feedback and ESP functions and a control method of the hydraulic braking system. Two oil paths arranged in an X shape in a pressure regulating module in the hydraulic system are provided with identical devices and have the identical control mode, and only the first oil path is taken as an example and is characterized in that a first pedal simulator, a third normally-open valve and a first hydraulic branch are arranged on a pipeline between a first normally-closed valve and an inlet of a first oil pump, one end of the first pedal simulator is connected with one end of the first normally-closed valve, the other end of the first pedal simulator is connected with the inlet of the first oil pump through the third normally-open valve and the first hydraulic branch in sequence; a first orifice, a third one-way valve, a first oil storage tank and a third normally-closed valve are sequentially arranged on the first hydraulic branch. A fourth one-way valve is arranged on a pipeline between the first normally-closed valve and a first pressure increasing valve, and a fourth normally-open valve is arranged on a pipeline between a first normally-open valve and the first pressure increasing valve.

Description

Hydraulic braking system with energy feedback and ESP function and its control method

technical field

The invention relates to a vehicle hydraulic stability control system and method, in particular to a hydraulic braking system with energy feedback and ESP functions and a control method thereof.

Background technique

The braking energy feedback system can recover the mechanical energy of the vehicle during the deceleration process of the vehicle, which is an important technology to improve the energy economy of the electric vehicle. But at the same time, the intervention of motor feedback braking will affect the braking comfort and braking safety of the vehicle under normal and extreme braking conditions. Therefore, in response to the requirements of braking energy feedback for electric vehicles, the research and development of energy feedback hydraulic braking system on the basis of the original braking system has become a hot spot that well-known automobile companies and parts manufacturers in the world are competing to develop. The energy feedback hydraulic braking system is an important factor that determines the braking safety, braking comfort and braking energy recovery efficiency of electric vehicles, and has become a common key technology and a core competitiveness component product of electric vehicles .

At present, the hydraulic braking system with braking energy feedback function proposed abroad can be mainly divided into three categories: the first category is the feedback hydraulic braking system based on the electronic hydraulic braking system (EHB), the most representative product It is Toyota's ECB system. The second category is the feedback hydraulic braking system based on the traditional vehicle dynamics control system (ESP, Electronic Stability Program, Electronic Stability Program). The most representative products are Bosch's ESP-hev and Continental's MK100 system. The third category is the regenerative hydraulic braking system based on the new master cylinder, the most representative product is Nissan's EDiB system. All of the above systems can realize the energy recovery function, while ensuring better braking comfort and safety. However, these systems have redesigned the traditional hydraulic braking system to varying degrees, adding high-pressure accumulators, electromagnetic proportional valves and other components that require high manufacturing precision, which are difficult to manufacture and costly.

Contents of the invention

In view of the above problems, the object of the present invention is to provide a hydraulic braking system with energy feedback and ESP functions and its control that can achieve maximum braking energy recovery and vehicle stability control under the premise of ensuring good pedal feel method.

In order to achieve the above object, the present invention adopts the following technical solutions: a hydraulic braking system with energy feedback and ESP function, which includes a brake pedal, a brake master cylinder, a brake wheel cylinder, a pressure adjustment module, and a brake controller BCU, vehicle controller VCU, motor controller MCU, drive motor and ESP controller, the brake master cylinder controls the brake wheel cylinder through the X-shaped oil circuit and the pressure regulation module arranged on the oil circuit The pressure is controlled, and the pressure regulation module includes first and second normally closed valves, first and second normally open valves, first and second high pressure dampers, first and second oil pumps, pump motors, first , The second one-way valve, the first and second low-pressure accumulators, the first, second, third and fourth pressure reducing valves, the first, second, third and fourth booster valves, the first and second The second master cylinder pressure sensor, the first, second, third, and fourth wheel cylinder pressure sensors, as well as the yaw rate sensor and the lateral acceleration sensor, are characterized in that: the first normally closed valve and the first oil pump inlet The first pedal simulator, the third normally open valve and the first hydraulic branch are arranged in sequence on the pipeline between them, one end of the first pedal simulator is connected to one end of the first normally closed valve, and the other end is sequentially The third normally open valve and the first hydraulic branch are connected to the inlet of the first oil pump; a fourth check valve is arranged on the pipeline between the first normally closed valve and the first booster valve, and the One end of the fourth one-way valve is connected to the first normally closed valve, and the other end is connected to the first booster valve; the pipeline between the first normally open valve and the first booster valve is provided with a second Four normally open valves, one end of the fourth normally open valve is connected to one end of the first normally open valve, and the other end is connected to one end of the first booster valve; the second normally closed valve and the second oil pump A second pedal simulator, a fifth normally open valve and a second hydraulic branch are arranged in sequence on the pipeline between the inlets, one end of the second pedal simulator is connected to one end of the second normally closed valve, and the other end The fifth normally open valve and the second hydraulic branch are sequentially connected to the inlet of the second oil pump; a sixth check valve is arranged on the pipeline between the second normally closed valve and the fourth booster valve, One end of the sixth one-way valve is connected to the second normally closed valve, and the other end is connected to the fourth boost valve; the pipeline between the second normally open valve and the fourth boost valve A sixth normally open valve is provided, one end of the sixth normally open valve is connected to one end of the second normally open valve, and the other end is connected to one end of the fourth boost valve.

The first hydraulic branch circuit includes a first throttle hole, a third one-way valve, a first oil storage tank and a third normally closed valve; one end of the first throttle hole is connected to the third normally open valve One end is connected, and the other end is connected with the third one-way valve; the other end of the third one-way valve is connected with one end of the first oil storage tank, and the other end of the first oil storage tank is connected with the One end of the third normally closed valve is connected, and the other end of the third normally closed valve is connected with the inlet of the first oil pump; the second hydraulic branch circuit includes a second orifice, a fifth check valve, The second oil storage tank and the fourth normally closed valve, one end of the second orifice is connected with one end of the fifth normally open valve, and the other end is connected with the fifth one-way valve; the fifth The other end of the check valve is connected to one end of the second oil storage tank, the other end of the second oil storage tank is connected to one end of the fourth normally closed valve, and the other end of the fourth normally closed valve It is connected with the inlet of the second oil pump.

A control method based on the hydraulic braking system with energy feedback and ESP function, which includes the following content: 1) the implementation process of integrated control of braking energy recovery and ESP function; according to the received yaw rate α, Lateral acceleration and the pressure of the brake master cylinder, the ESP controller judges whether the vehicle is skidding, and the vehicle controller VCU selects regenerative braking or traditional ESP control according to whether the vehicle is skidding; 2) Braking energy recovery function The implementation process of the brake controller BCU controls the pressure adjustment module, and the motor controller MCU controls the driving motor to realize the braking energy recovery function; 3) The implementation process of the ESP function; the ESP controller controls the pressure adjustment module to realize the ESP function.

In the step 1), the vehicle controller VCU selects to adopt regenerative braking or traditional ESP control according to whether the vehicle is skidding, which specifically includes: during the running of the vehicle, the yaw rate sensor detects the yaw rate of the vehicle α and transmit it to the ESP controller. The lateral acceleration sensor detects the lateral acceleration of the vehicle and transmits it to the ESP controller. Both the first and second master cylinder pressure sensors detect the pressure of the brake master cylinder and transmit it to the ESP controller; The ESP controller calculates the nominal yaw rate α _NO , the nominal center-of-mass sideslip angle β _NO and the actual center-of-mass sideslip angle β through the observation algorithm; the ESP controller compares |α-α _NO | and |β-β _NO | Compare the threshold value α _lim of the set yaw rate with the threshold value β _lim of the side slip angle of the center of mass. When |α-α _NO |<α _lim and |β-β _NO |<β _lim , the vehicle control When |α-α _NO |＞α _lim or |β-β _NO |＞β _lim , the vehicle controller VCU chooses to use traditional ESP control.

In the step 2), the brake controller BCU controls the pressure adjustment module to realize the braking energy recovery function, which specifically includes: the pressure value P and the pressure change rate of the brake master cylinder are both measured by the first and second master cylinder pressure sensors ΔP/Δt is detected, and the detected results are transmitted to the brake controller BCU; the brake controller BCU calculates the total braking torque T _total and the feedback system required by the left and right front wheels according to the pressure value P The dynamic torque command value T is sent to the vehicle controller VCU through the CAN bus; the vehicle controller VCU calculates the maximum feedback torque T ₁ that the driving motor can provide through the current motor speed and battery SOC data, and the vehicle controller VCU8 Compare the absolute value of the maximum feedback torque value T ₁ with the absolute value of the feedback braking torque command value T, take the smaller value of the two as the motor feedback torque command value T _{reg_cmd} , and set the feedback braking torque command value T Send to the motor controller MCU; the motor controller MCU controls the actual feedback torque value T _act output by the drive motor according to the received feedback braking torque command value T; when the total braking torque T act required by the left front wheel and the right front wheel When _total is less than the actual feedback torque value T _act output by the drive motor, the brake controller BCU controls the second and third pressure reducing valves through the duty ratio control method, and the wheel cylinder brake fluid of the left front wheel passes through the second pressure reducing valve. The pressure valve flows into the first low-pressure accumulator, the wheel cylinder brake fluid of the right front wheel flows into the second low-pressure accumulator through the third pressure-reducing valve, and the brake controller BCU through the second and third pressure-reducing valves Duty ratio control is performed to realize the decompression of the front wheel cylinders at different rates; when the total braking torque T _total required by the left and right front wheels is greater than the actual feedback torque value T _act output by the drive motor, the braking control The controller BCU controls the third to sixth normally open valves, and the third to fourth normally closed valves are powered on, and controls the pump motor to work; the first oil pump brakes the first oil storage tank and the first low pressure accumulator The hydraulic fluid is pumped into the left front wheel cylinder through the first high-pressure damper and the second booster valve in turn, and the pressure of the brake fluid in the first oil storage tank and the first low-pressure accumulator is used to compensate the brake fluid required by the left front wheel. The difference between the total braking torque T _total and the actual feedback torque value T _act output by the drive motor; the second oil pump passes the brake fluid in the second oil storage tank and the second low-pressure accumulator through the second high-pressure damper in sequence and the third pressure boost valve pumped into the right front wheel cylinder, the pressure of the brake fluid in the second oil storage tank and the second low-pressure accumulator is used to compensate the total braking torque T _total required by the right front wheel and the driving motor The difference of the output actual feedback torque value T _act ; the brake controller BCU controls the third normally closed valve and the pump motor through the duty cycle control method to realize the control of the pressurization rate of the left front wheel cylinder, and the brake controller The BCU controls the fourth normally closed valve and the pump motor through the duty cycle control method to realize the control of the pressurization rate of the right front wheel cylinder; as the vehicle speed decreases, the feedback torque generated by the drive motor gradually decreases, and the vehicle controller VCU Control the feedback braking torque to decrease from the current value to zero with a certain decreasing slope, and the feedback While the torque is gradually decreasing, the brake controller BCU adopts the duty cycle control method to control the third and fourth normally closed valves, pump motors, second and third boost valves, so that the first oil storage tank and the first low pressure The brake fluid in the accumulator enters the left front wheel cylinder, so that the brake fluid in the second oil storage tank and the second low-pressure accumulator enters the right front wheel cylinder to reduce the feedback torque by the same The slope increases the pressure of the front axle wheel cylinder until the brake controller BCU resets the first to sixth normally open valves, the first to fourth normally closed valves, the first to fourth boost valves, the first to fourth Pressure reducing valve and pump motor.

In the step 3), the ESP controller controls the pressure regulation module to realize the ESP function, which specifically includes: when the right rear wheel needs to be boosted, the brake controller BCU adopts a duty cycle control method to control the pump motor and the first Controlled by a booster valve, the pump motor passes the brake fluid in the brake master cylinder through the first normally closed valve, the third normally open valve, the first oil pump, the first high pressure damper, the fourth normally open valve and the The first booster valve pumps into the right rear wheel; when the left front wheel needs to be boosted, the brake controller BCU uses the duty ratio control method to control the pump motor and the second booster valve, and the pump motor will control The brake fluid in the active master cylinder passes through the first normally closed valve, the third normally open valve, the first oil pump, the first high pressure damper and the second booster valve and then pumps into the left front wheel.

Due to the adoption of the above technical scheme, the present invention has the following advantages: 1. Since the present invention improves the pressure regulating module in the traditional hydraulic braking system, it is sequentially arranged on the pipeline between the first normally closed valve and the inlet of the first oil pump. The first pedal simulator, the third normally open valve and the first hydraulic branch circuit, the third one-way valve is arranged on the pipeline between the first normally closed valve and the first boost valve, and the first normally open valve and the first hydraulic branch A fourth normally open valve is set on the pipeline between the booster valves; a second pedal simulator, a fifth normally open valve and a second hydraulic branch are sequentially set on the pipeline between the second normally closed valve and the inlet of the second oil pump The fifth check valve is set on the pipeline between the second normally closed valve and the fourth boost valve, and the sixth normally open valve is set on the pipeline between the second normally open valve and the fourth boost valve; The hydraulic braking of the front wheel of the present invention works in harmony with the regenerative braking of the drive motor, and in the regenerative braking process, the brake master cylinder is not mechanically connected to the front wheel brake, but is connected to the pedal simulator and the liquid storage tank, Therefore, while the drive motor completes the energy feedback, the pedal feeling of the pedals will not be affected, and the braking energy can be recovered to the maximum extent, and at the same time, ABS (Anti-lock Brake System, anti-lock braking system), TCS (Traction Control System, traction control system) and ESP and other functions, while improving the energy economy of electric drive vehicles, ensure the safety of the vehicle. 2. The present invention only needs to simply modify the ESP pressure regulator in the vehicle braking system in the prior art without redesigning, and avoids the use of high-pressure accumulators, electromagnetic proportional valves and other parts that are difficult to manufacture; The functions of energy feedback, ABS, TCS and ESP can be realized by reasonable and reliable design of the software in the controller of the hybrid or pure electric drive vehicle; the modification of the hydraulic braking system is relatively small, and the braking energy recovery efficiency is high. The pedal feels good, the invention can realize integrated control of braking energy recovery and ESP, without affecting the driver's driving habits, the braking performance meets the requirements of laws and regulations, improves the vehicle economy, and reduces the cost of hybrid vehicles and pure electric vehicle systems. Development cost, improved energy recovery efficiency during braking. Based on the above advantages, the present invention can be widely applied to electric drive vehicles.

Description of drawings

Fig. 1 is a structural schematic diagram of a hydraulic pipeline in a traditional vehicle dynamics control system;

Fig. 2 is a schematic diagram of the overall structure of the hydraulic braking system with energy feedback and ESP functions according to the present invention; wherein, - represents mechanical connection, and --- represents signal connection.

Detailed ways

The present invention will be described in detail below in conjunction with the accompanying drawings and embodiments.

As shown in Figure 1, the hydraulic pipeline in the traditional vehicle dynamics control system is mainly composed of the oil storage chamber 1, the vacuum booster 2, the brake pedal 3, the brake master cylinder 4, the brake wheel cylinder 5 and the pressure regulation module 6 and so on. The brake master cylinder 4 controls the pressure of the brake wheel cylinder 5 through the X-shaped oil circuit and the pressure regulating module 6 provided on the oil circuit. Wherein, the brake wheel cylinder 5 includes a right rear wheel cylinder 51 , a left front wheel cylinder 52 , a right front wheel cylinder 53 and a left rear wheel cylinder 54 . The brake master cylinder 4 controls the right rear wheel cylinder 51 and the left front wheel cylinder 52 respectively through the first oil circuit, and controls the right front wheel cylinder 53 and the left rear wheel cylinder 54 respectively through the second oil circuit .

Wherein, the pressure regulating module 6 includes first and second normally closed valves 601 and 602, first and second normally open valves 603 and 604, first and second high pressure dampers 605 and 606, first and second oil pumps 607 , 608, pump motor 609, first and second one-way valves 610 and 611, first and second low pressure accumulators 612 and 613, first, second, third and fourth pressure reducing valves 614 and 615, 616, 617, first, second, third, fourth pressure boost valves 618, 619, 620, 621, first, second master cylinder pressure sensors 622, 623, first, second, third, fourth Wheel cylinder pressure sensors 624, 625, 626, 627, and a yaw rate sensor (not shown in the figure) and a lateral acceleration sensor (not shown in the figure). Wherein, the first master cylinder pressure sensor 622 is arranged at the first oil outlet of the brake master cylinder 6, the second master cylinder pressure sensor 623 is arranged at the second oil outlet of the brake master cylinder 6, and the first and second 2. The third and fourth wheel cylinder pressure sensors 624, 625, 626, and 627 are sequentially arranged at the entrances of the right rear wheel cylinder 51, the left front wheel cylinder 52, the right front wheel cylinder 53, and the left rear wheel cylinder 54. place. Both the first and second oil pumps 607 and 608 are connected to a pump motor 609 .

The pressure regulating module 6 has the same devices and control methods in the two X-shaped oil circuits, and only the first oil circuit is used as an example for illustration.

During the supercharging process, when the ESP function is realized, the first oil outlet of the brake master cylinder 6 passes through the first normally closed valve 601, the first oil pump 607, the first high pressure damper 605 and the first supercharging valve 618 and the right The rear wheel cylinder 51 is connected with the left front wheel cylinder 52 through the first normally closed valve 601, the first oil pump 607, the first high pressure damper 605 and the second boost valve 619; , the first oil outlet of the brake master cylinder 6 is connected to the right rear wheel cylinder 51 through the first normally open valve 603 and the first boost valve 618 in sequence, and at the same time through the first normally open valve 603 and the second boost valve The valve 619 is connected to the left front wheel cylinder 52 .

During the decompression process, the right rear wheel cylinder 51 passes through the first decompression valve 614, the first low-pressure accumulator 612, the first check valve 610, the first oil pump 607, the first high-pressure damper 605 and the first constant pressure in sequence. The open valve 603 is connected with the first oil outlet of the brake master cylinder 6 . The left front wheel cylinder 52 passes through the second decompression valve 615, the first low-pressure accumulator 612, the first check valve 610, the first oil pump 607, the first high-pressure damper 605 and the first normally-open valve 603 to control Move the first oil outlet of master cylinder 6.

As shown in FIG. 2 , the difference between the hydraulic braking system with energy feedback and ESP functions of the present invention and the hydraulic braking system in the prior art lies in the modification of the pressure regulating module 6 . The devices and control methods set in the two oil circuits of the X-type layout of the modified pressure regulation module 6 are the same, which specifically include:

On the pipeline between the first normally closed valve 601 and the inlet of the first oil pump 607, the first pedal simulator 628, the third normally open valve 629 and the first hydraulic branch 630 are arranged in sequence, and one end of the first pedal simulator 628 is connected to One end of the first normally closed valve 601 is connected, and the other end thereof is connected to the inlet of the first oil pump 607 through the third normally open valve 629 and the first hydraulic branch 630 in sequence.

The first hydraulic branch 630 is provided with a first throttle hole 631 , a third one-way valve 632 , a first oil storage tank 633 and a third normally closed valve 634 . One end of the first throttle hole 631 is connected with one end of the third normally open valve 629, and the other end is connected with the third one-way valve 632; the other end of the third one-way valve 632 is connected with one end of the first oil storage tank 633 , the other end of the first oil storage tank 633 is connected to one end of the third normally closed valve 634 , and the other end of the third normally closed valve 634 is connected to the inlet of the first oil pump 607 .

A fourth one-way valve 635 is arranged on the pipeline between the first normally closed valve 601 and the first booster valve 618, one end of the fourth one-way valve 635 is connected with the first normally closed valve 601, and the other end is connected with the first Boost valve 618 is connected.

A fourth normally open valve 636 is arranged on the pipeline between the first normally open valve 603 and the first booster valve 618, one end of the fourth normally open valve 636 is connected with one end of the first normally open valve 603, and the other end is connected with the first normally open valve 603. One end of the first boost valve 618 is connected.

On the pipeline between the second normally closed valve 602 and the inlet of the second oil pump 608, a second pedal simulator 637, a fifth normally open valve 638 and a second hydraulic branch 639 are sequentially arranged, and one end of the second pedal simulator 637 is connected to One end of the second normally closed valve 602 is connected, and the other end thereof is connected to the inlet of the second oil pump 608 through the fifth normally open valve 638 and the second hydraulic branch 639 in sequence.

The second hydraulic branch 639 is provided with a second throttle hole 640 , a fifth one-way valve 641 , a second oil storage tank 642 and a fourth normally closed valve 643 . One end of the second orifice 640 is connected to one end of the fifth normally open valve 638, and the other end is connected to the fifth one-way valve 641; the other end of the fifth one-way valve 641 is connected to one end of the second oil storage tank 642 , the other end of the second oil storage tank 642 is connected to one end of the fourth normally closed valve 643 , and the other end of the fourth normally closed valve 643 is connected to the inlet of the second oil pump 608 .

A sixth one-way valve 644 is arranged on the pipeline between the second normally closed valve 602 and the fourth boost valve 621, one end of the sixth one-way valve 644 is connected with the second normally closed valve 602, and the other end is connected with the fourth The boost valve 621 is connected.

A sixth normally open valve 645 is arranged on the pipeline between the second normally open valve 604 and the fourth boost valve 621, one end of the sixth normally open valve 645 is connected with one end of the second normally open valve 604, and the other end is connected with the second normally open valve 604. One end of the fourth boost valve 621 is connected.

The brake controller BCU7 controls the first, second, third and fourth normally closed valves 601, 602, 634 and 643, and the first, second, third, fourth, fifth and sixth normally open valves 603, 604, 629, 636, 638, 645, first, second, third, fourth, fifth, sixth check valve 610, 611, 632, 635, 641, 644, first, second, third , the fourth pressure reducing valves 614, 615, 616, 617, the first, second, third, and fourth pressure increasing valves 618, 619, 620, 621, and the pump motor 609 operate. The communication between the brake controller BCU7 and the vehicle controller VCU8, and between the vehicle controller VCU8 and the motor controller MCU9 is carried out through the CAN network. The motor controller MCU9 controls the drive motor 10 . The yaw rate sensor, the lateral acceleration sensor, and the first and second master cylinder pressure sensors 622 , 623 all transmit detected signals to the ESP controller 11 .

Adopt the hydraulic braking system with energy feedback and ESP function of the present invention to carry out hydraulic braking, which specifically includes the following contents:

1) Implementation process of integrated control of braking energy recovery and ESP functions

Usually, when there is no body skidding trend and the brake controller BCU7 detects the braking energy feedback switch signal, that is, when the braking energy recovery is allowed, the drive motor 10 is used for braking as much as possible to achieve the maximum feedback of braking energy the goal of. When the body tends to skid, the regenerative braking is quickly withdrawn, and the traditional ESP works to ensure the safety of the vehicle.

During the running of the vehicle, the yaw rate sensor detects the yaw rate α of the vehicle and transmits it to the ESP controller 11, and the lateral acceleration sensor detects the lateral acceleration of the vehicle and transmits it to the ESP controller 11. Both the master cylinder pressure sensors 622 and 623 detect the pressure of the brake master cylinder 4 and transmit it to the ESP controller 11 .

The ESP controller 11 calculates the nominal yaw rate α _NO , the nominal center-of-mass sideslip angle β _NO and the actual center-of-mass sideslip angle β through the observation algorithm.

The ESP controller 11 compares |α-α _NO | and |β-β _NO | with the preset threshold value α _lim of the yaw rate and the threshold value β _lim of the side slip angle of the center of mass, respectively. When |α-α _NO |<α _lim and |β-β _NO |<β _lim , the vehicle does not slip, and the vehicle controller VCU8 enables the energy recovery function through the braking energy feedback switch signal. At this time, it can be used Regenerative braking to improve the energy economy of the vehicle; when |α-α _NO |＞α _lim or |β-β _NO |＞β _lim , the vehicle slips, and the vehicle controller VCU8 feeds back the switching signal through the braking energy Stop the energy recovery function, and immediately exit the braking energy recovery function at this time, and restore the traditional ESP control.

2) Implementation process of braking energy recovery function

Taking the centralized front wheel drive of an electric drive vehicle as an example, when the driver depresses the brake pedal 1 to perform braking, the brake controller BCU7 detects whether the vehicle controller VCU8 sends a braking energy feedback switch signal. When the brake controller BCU7 detects the braking energy feedback switch signal, that is, when the braking energy recovery is allowed, the first and second normally open valves 603 and 604 and the first and second normally closed valves 601 and 602 are powered on to control The first oil outlet of the master cylinder 4 communicates with the first pedal simulator 628 through the first normally closed valve 601, and the first pedal simulator 628 communicates with the first hydraulic branch 630 through the third normally open valve 629; At the same time, the first oil outlet of the brake master cylinder 6 is connected to the right rear wheel cylinder through the first normally closed valve 601 , the fourth one-way valve 635 and the first boost valve 618 in sequence. The second oil outlet of the brake master cylinder 6 communicates with the second pedal simulator 637 through the second normally closed valve 602 , and the second pedal simulator 637 communicates with the second hydraulic branch circuit 639 through the fifth normally open valve 638 At the same time, the second oil outlet of the brake master cylinder 6 is connected to the left rear wheel cylinder through the second normally closed valve 602, the sixth one-way valve 644 and the fourth boost valve 621 in sequence. Otherwise, when the brake controller BCU7 does not detect the braking energy feedback switch signal, that is, when the braking energy recovery is not allowed, the first and second normally open valves 603 and 604 and the first and second normally closed valves 601 and 602 Power off, the first oil outlet of the brake master cylinder 6 is connected to the left front wheel cylinder through the first normally open valve 603 and the second booster valve 619 in sequence, and at the same time through the first normally open valve 603 and the fourth normally open valve The open valve 636 and the first boost valve 618 are connected to the right rear wheel cylinder; the second oil outlet of the brake master cylinder 6 is connected to the right front wheel cylinder through the second normally open valve 604 and the third boost valve 620 in sequence. connected, and at the same time connected to the left rear wheel cylinder through the second normally open valve 604, the sixth normally open valve 645 and the fourth boost valve 621 in sequence.

Both the first and second master cylinder pressure sensors 622, 623 detect the pressure value P and the pressure change rate ΔP/Δt of the brake master cylinder 6, and transmit the detected results to the brake controller BCU7, the brake control The controller BCU7 calculates the total braking torque T _total and the feedback braking torque command value T required by the left front wheel cylinder 52 and the right front wheel cylinder 53 according to the pressure value P, and sends them to the vehicle controller through the CAN bus VCU8. The vehicle controller VCU8 calculates the maximum feedback torque T ₁ that the drive motor 10 can provide by calculating the current motor speed, battery SOC and other data, and the vehicle controller VCU8 compares the absolute value of the maximum feedback torque value T ₁ with the feedback braking torque command The absolute value of the value T is compared, and the smaller value of the two is taken as the motor feedback torque command value T _{reg_cmd} , and the feedback braking torque command value T is sent to the motor controller MCU9, and the motor controller MCU9 according to the received feedback system The power torque command value T controls the actual feedback torque value T _act output by the driving motor 10 .

When the total braking torque T _total required by the left front wheel cylinder 52 and the right front wheel cylinder 53 is smaller than the actual feedback torque value T _act output by the driving motor 10 , the hydraulic braking force to the front wheel cylinder needs to be reduced. The brake controller BCU7 controls the second and third decompression valves 615 and 616 through the duty cycle control method, and the brake fluid of the left front wheel cylinder 52 flows into the first low-pressure accumulator 612 through the second decompression valve 615 , the brake fluid of the right front wheel cylinder 53 flows into the second low-pressure accumulator 613 through the third decompression valve 616 . The brake controller BCU7 realizes the decompression of the front wheel cylinders at different rates by controlling the duty ratio of the second and third decompression valves 615 and 616 . The larger the duty cycle, the faster the decompression rate.

When the total braking torque T _total required by the left front wheel cylinder 52 and the right front wheel cylinder 53 is greater than the actual feedback torque value T _act output by the drive motor 10, the feedback braking torque of the drive motor cannot fully meet the needs of the left front wheel wheel. The brake pressure of cylinder 52 and right front wheel cylinder 53 needs to supplement the pressure of front axle wheel cylinder with hydraulic pressure this moment. The brake controller BCU7 controls the third to sixth normally open valves 629 , 636 , 638 , 645 and the third to fourth normally closed valves 634 , 643 to be powered on, and controls the pump motor 609 to work. The first oil pump 607 pumps the brake fluid in the first oil storage tank 633 and the first low-pressure accumulator 612 into the left front wheel cylinder 52 through the first high-pressure damper 605 and the second pressure-increasing valve 619 in sequence. The pressure of the brake fluid in an oil storage tank 633 and the first low-pressure accumulator 612 is used to compensate the difference between the total braking torque T _total required by the left front wheel cylinder 52 and the actual feedback torque value T _act output by the drive motor 10 difference. The second oil pump 2 pumps the brake fluid in the second oil storage tank 642 and the second low-pressure accumulator 613 into the right front wheel cylinder 53 through the second high-pressure damper 606 and the third boost valve 620 in sequence. The pressure of the brake fluid in the second oil storage tank 642 and the second low-pressure accumulator 613 is used to compensate the total braking torque T _total required by the right front wheel cylinder 53 and the actual feedback torque value T _act output by the drive motor 10 difference.

The brake controller BCU7 controls the third normally closed valve 634 and the pump motor 609 through the duty ratio control method to realize the control of the pressurization rate of the left front wheel cylinder 52, and the brake controller BCU7 controls the first The four normally closed valves 643 and the pump motor 609 realize the control of the pressurization rate of the right front wheel cylinder 53, and the larger the duty cycle, the faster the pressurization rate.

As the vehicle speed decreases, the feedback torque generated by the driving motor 10 gradually decreases (this is determined by the characteristics of the motor itself), and the vehicle controller VCU8 controls the feedback braking torque to decrease from the current value to zero with a certain decreasing slope. While the feedback torque is gradually decreasing, the brake controller BCU7 adopts the duty ratio control method to control the third normally closed valve 634, the fourth normally closed valve 643, the pump motor 609, the second boost valve 619, the third boost valve 620, make the brake fluid in the first oil storage tank 633 and the first low-pressure accumulator 612 enter the left front wheel cylinder 52, and make the brake fluid in the second oil storage tank 642 and the second low-pressure accumulator 613 Liquid enters the right front wheel cylinder 53, increases the pressure of the front axle wheel cylinder with the same slope as the feedback torque decreases (here refers to the absolute value of the slope), until the brake controller BCU7 resets the first to the second Six normally open valves 603, 604, 629, 636, 638, 645, first to fourth normally closed valves 601, 602, 634, 643, first to fourth booster valves 618, 619, 620, 621, first To the fourth relief valve 614, 615, 616, 617 and pump motor 609.

During the entire braking process, the brake controller BCU7 coordinates and controls the feedback braking force and the hydraulic braking force to ensure that the total braking force is always consistent with the driver's desired braking force.

3) Implementation process of ESP function

When |α-α _NO |>α _lim or |β-β _NO |>β _lim , in order to ensure the body attitude and driving safety, the ESP controller 11 needs to intervene in the torque and braking force of the driving motor 10; the ESP control The driving motor torque command value T _{motor_ESP} issued by the controller 11 is transmitted to the vehicle controller VCU8 through the CAN network, and the hydraulic braking torque command value T _{hyd_ESP} issued by the ESP controller 11 is transmitted to the brake controller BCU7 through the CAN network.

Taking the active pressurization of the right rear wheel cylinder 51 and the left front wheel cylinder 52 as an example, the control process of the hydraulic pressure during the ESP process will be described below.

When it is necessary to pressurize the right rear wheel cylinder 51, the brake controller BCU7 controls the pump motor 609 and the first boost valve 618 by using a duty ratio control method, and the pump motor 609 will brake the pressure in the master cylinder 6. The brake fluid is pumped into the right rear through the first normally closed valve 601, the third normally open valve 629, the first oil pump 607, the first high pressure damper 605, the fourth normally open valve 636 and the first booster valve 618 in sequence. round 5.

When the left front wheel cylinder 52 needs to be pressurized, the brake controller BCU7 controls the pump motor 609 and the second booster valve 619 by using the duty ratio control method, and the brake fluid in the brake master cylinder 6 The oil is pumped into the left front wheel 6 through the first normally closed valve 601 , the third normally open valve 629 , the first oil pump 607 , the first high pressure damper 605 and the second boost valve 619 in sequence. Among them, the brake controller BCU7 adopts the method of duty ratio control to adjust the pump oil pressure by controlling the pump motor 609, and the brake controller BCU7 adopts the method of duty ratio control to adjust the pressure of the right rear wheel cylinder by controlling the first booster valve 618. 51 boosting rate, the brake controller BCU7 adjusts the boosting rate of the left front wheel cylinder 52 by controlling the second boosting valve 619 by using a duty ratio control method.

The brake energy feedback solution proposed by the present invention can obtain the same brake pedal feeling as that of a traditional car, because:

(1) The modified ESP pressure regulator 6, the brake oil circuit of the left front wheel cylinder 52 and the right front wheel cylinder 53 have completed the mechanical decoupling with the brake pedal 1 when the braking energy is fed back, and the added No. 1. The second pedal simulators 628 and 637 and the first and second fluid storage tanks 633 and 642 can make the brake fluid of the master cylinder 6 flow into the first and second pedal simulations when the brake pedal 1 is depressed In the device 628,637, the feeling of stepping on the brake pedal 1 is the same as that of a traditional car;

(2) During the braking energy feedback process, when it is necessary to pressurize the front axle wheel cylinder, the third and fifth normally open valves 629 and 638 are powered on, and the brake controller BCU7 uses the duty ratio control method to 3. The fourth normally closed valves 634 and 643 are controlled. The ESP pump motor 609 pumps the brake fluid in the first oil storage tank 633 and the first low-pressure accumulator 612 into the 6-wheel cylinder of the left front wheel. The ESP pump The motor 609 pumps the brake fluid in the second oil storage tank 642 and the second low-pressure accumulator 613 into the right front wheel 7 wheel cylinder, so that the pressure of the brake master cylinder 6 is not affected, ensuring a good pedal feeling.

Therefore, during the braking energy recovery process, the modified hydraulic braking system can make the driver not feel the discomfort of the brake pedal caused by the hydraulic braking force adjustment during the energy feedback process.

The above-mentioned embodiments are only used to illustrate the present invention, wherein the structure, connection mode and method steps of each component can be changed to some extent, and any equivalent transformation and improvement carried out on the basis of the technical solution of the present invention should not be used. excluded from the protection scope of the present invention.

Claims (6)

1. one kind has the hydraulic brake system of energy feedback and ESP function, it comprises brake pedal, master brake cylinder, brake wheel cylinder, pressure adjusting module, brake controller BCU, entire car controller VCU, electric machine controller MCU, drive motor and ESP controller, the pressure of described pressure adjusting module to described brake wheel cylinder that the oil circuit that described master brake cylinder is arranged by X-type and oil circuit are arranged controls, described pressure adjusting module comprises first, second normal close valve, first, second normally open valve, first, second high-tension damper, first, second oil pump, pump motor, first, second check valve, first, second low pressure accumulator, first, second, 3rd, 4th reducing valve, first, second, 3rd, 4th pressure charging valve, first, second master cylinder pressure sensor, first, second, 3rd, fourth round cylinder pressure transducer, and yaw-rate sensor and lateral acceleration sensor, it is characterized in that:

Pipeline between described first normal close valve and the first oil pump inlet sets gradually the first pedal simulator, the 3rd normally open valve and the first hydraulic branch, one end of described first pedal simulator is connected with one end of described first normal close valve, and its other end is connected with described first oil pump inlet with the first hydraulic branch by described 3rd normally open valve successively; Pipeline between described first normal close valve and the first pressure charging valve is arranged the 4th check valve, one end of described 4th check valve is connected with described first normal close valve, and its other end is connected with described first pressure charging valve; Pipeline between described first normally open valve and the first pressure charging valve is arranged the 4th normally open valve, one end of described 4th normally open valve is connected with one end of the first normally open valve, and its other end is connected with one end of described first pressure charging valve;

Pipeline between described second normal close valve and the second oil pump inlet sets gradually the second pedal simulator, 5 constant virtues valve opening and the second hydraulic branch, one end of described second pedal simulator is connected with one end of described second normal close valve, and its other end is connected with the entrance of the second hydraulic branch with described second oil pump by described 5 constant virtues valve opening successively; Pipeline between described second normal close valve and the 4th pressure charging valve is arranged the 6th check valve, one end of described 6th check valve is connected with described second normal close valve, and its other end is connected with described 4th pressure charging valve; Pipeline between described second normally open valve and the 4th pressure charging valve is arranged the 6th normally open valve, one end of described 6th normally open valve is connected with one end of described second normally open valve, and its other end is connected with one end of described 4th pressure charging valve.

2. there is the hydraulic brake system of energy feedback and ESP function as claimed in claim 1, it is characterized in that: described first hydraulic branch comprises first segment discharge orifice, the 3rd check valve, the first petrol storage tank and the 3rd normal close valve; One end of described first segment discharge orifice is connected with one end of described 3rd normally open valve, and its other end is connected with described 3rd check valve; The other end of described 3rd check valve is connected with one end of described first petrol storage tank, and the other end of described first petrol storage tank is connected with one end of described 3rd normal close valve, and the other end of described 3rd normal close valve is connected with the entrance of described first oil pump; Described second hydraulic branch comprises second section discharge orifice, the 5th check valve, the second petrol storage tank and the 4th normal close valve, and one end of described second section discharge orifice is connected with one end of described 5 constant virtues valve opening, and its other end is connected with described 5th check valve; The other end of described 5th check valve is connected with one end of described second petrol storage tank, and the other end of described second petrol storage tank is connected with one end of described 4th normal close valve, and the other end of described 4th normal close valve is connected with the entrance of described second oil pump.

3., based on a control method as described in any one of claim 1 or 2 with the hydraulic brake system of energy feedback and ESP function, it comprises following content:

1) implementation process that controls of Brake energy recovery and ESP function integration;

According to the pressure of the yaw velocity α, lateral acceleration and the master brake cylinder that receive, ESP controller judges whether vehicle breaks away, and whether entire car controller VCU occurs to break away according to vehicle is selected to adopt regenerative braking or adopt traditional E SP to control;

2) implementation process of braking energy recovering function;

Brake controller BCU control presssure adjustment module, electric machine controller MCU control drive motor and realize braking energy recovering function;

3) implementation process of ESP function;

ESP controller control presssure adjustment module realizes ESP function.

4. there is the control method of the hydraulic brake system of energy feedback and ESP function as claimed in claim 3, it is characterized in that: described step 1) in, whether entire car controller VCU occurs to break away according to vehicle is selected to adopt regenerative braking or adopt traditional E SP to control, and it specifically comprises:

In vehicle travel process, yaw-rate sensor detects the yaw velocity α of car load and transfers to ESP controller, lateral acceleration sensor detects the lateral acceleration of car load and transfers to ESP controller, and first, second master cylinder pressure sensor all detects the pressure of master brake cylinder and transfers to ESP controller;

ESP controller calculates nominal yaw velocity α by observation algorithm _nO, nominal side slip angle β _nOand actual side slip angle β;

ESP controller is incited somebody to action | α-α _nO| with | β-β _nO| respectively with the threshold value α of yaw velocity preset _limwith the threshold value of side slip angle _limcompare, when | α-α _nO| < α _limand | β-β _nO| < β _limtime, entire car controller VCU selects to adopt regenerative braking; When | α-α _nO| > α _limor | β-β _nO| > β _limtime, entire car controller VCU selects to adopt traditional E SP to control.

5. there is the control method of the hydraulic brake system of energy feedback and ESP function as claimed in claim 3, it is characterized in that: described step 2) in, brake controller BCU control presssure adjustment module realizes braking energy recovering function, and it specifically comprises:

First and second master cylinder pressure sensors all detect the pressure value P of master brake cylinder and pressure change rate Δ P/ Δ t, and the result detected is transferred to brake controller BCU; Brake controller BCU calculates the total braking force square T needed for the near front wheel and off front wheel according to pressure value P _totalwith regenerative braking torque command value T, and send to entire car controller VCU by CAN; Entire car controller VCU calculates by current motor rotating speed, battery SOC data the maximum Return moment T that drive motor can provide ₁, entire car controller VCU8 is by maximum Return moment value T ₁absolute value and the absolute value of regenerative braking torque command value T compare, get both smaller values as motor feedback torque command value T _{reg_cmd}, regenerative braking torque command value T is sent to electric machine controller MCU; Electric machine controller MCU controls the actual Return moment value T of drive motor output according to the regenerative braking torque command value T received _act;

As the total braking force square T needed for the near front wheel and off front wheel _totalbe less than the actual Return moment value T that drive motor exports _acttime, brake controller BCU is controlled second, third reducing valve by Duty ratio control method, the wheel cylinder braking liquid of the near front wheel flows in the first low pressure accumulator by the second reducing valve, the wheel cylinder braking liquid of off front wheel flows in the second low pressure accumulator by the 3rd reducing valve, and brake controller BCU is by carrying out the decompression of Duty ratio control realization to front-wheel wheel cylinder different rates to second, third reducing valve;

As the total braking force square T needed for the near front wheel and off front wheel _totalbe greater than the actual Return moment value T that drive motor exports _acttime, brake controller BCU controls the 3rd to the 6th normally open valve, and the 3rd to the 4th normal close valve powers on, and control pump machine operation; First oil pump is by the braking liquid in the first petrol storage tank and the first low pressure accumulator, pump into the near front wheel wheel cylinder by the first high-tension damper and the second pressure charging valve successively, in the first petrol storage tank and the first low pressure accumulator, the pressure of braking liquid is used for compensating the total braking force square T needed for the near front wheel _totalthe actual Return moment value T exported with drive motor _actdifference; Second oil pump is by the braking liquid in the second petrol storage tank and the second low pressure accumulator, pump into off front wheel wheel cylinder by the second high-tension damper and the 3rd pressure charging valve successively, in the second petrol storage tank and the second low pressure accumulator, the pressure of braking liquid is used for compensating the total braking force square T needed for off front wheel _totalthe actual Return moment value T exported with drive motor _actdifference;

Brake controller BCU controls the 3rd normal close valve and pump motor by Duty ratio control method, realize the control to the near front wheel wheel cylinder rate of pressurization, brake controller BCU controls the 4th normal close valve and pump motor by Duty ratio control method, realizes the control to off front wheel wheel cylinder rate of pressurization;

Along with the speed of a motor vehicle reduces, the Return moment that drive motor produces diminishes gradually, entire car controller VCU controls regenerative braking moment and is reduced to zero with certain reduction slope from currency, while Return moment reduces gradually, brake controller BCU adopts Duty ratio control method to control the 3rd, 4th normal close valve, pump motor, second, 3rd pressure charging valve, the braking liquid in the first petrol storage tank and the first low pressure accumulator is made to enter in the near front wheel wheel cylinder, the braking liquid in the second petrol storage tank and the second low pressure accumulator is made to enter in off front wheel wheel cylinder, to reduce with Return moment the pressure that identical slope increases front axle wheel cylinder, until stop, brake controller BCU resets the first to the 6th normally open valve, first to fourth normal close valve, first to fourth pressure charging valve, first to fourth reducing valve and pump motor.

6. there is the control method of the hydraulic brake system of energy feedback and ESP function as claimed in claim 3, it is characterized in that: described step 3) in, ESP controller control presssure adjustment module realizes ESP function, and it specifically comprises:

When needs carry out supercharging to off hind wheel, brake controller BCU adopts the method for Duty ratio control to control pump motor and the first pressure charging valve, and the braking liquid in master brake cylinder is pumped into off hind wheel by pump motor successively after the first normal close valve, the 3rd normally open valve, the first oil pump, the first high-tension damper, the 4th normally open valve and the first pressure charging valve;

When needs carry out supercharging to the near front wheel, brake controller BCU adopts the method for Duty ratio control to control pump motor and the second pressure charging valve, and the braking liquid in master brake cylinder is pumped into the near front wheel by pump motor successively after the first normal close valve, the 3rd normally open valve, the first oil pump, the first high-tension damper and the second pressure charging valve.