Kinetic energy recovery control system of electric automobile

Abstract

The utility model provides an electric automobile kinetic energy recovery control system, and belongs to the technical field of electric automobile kinetic energy recovery control. The technical problem to be solved is to provide the improvement of the hardware structure of the kinetic energy recovery control system of the electric vehicle. According to the technical scheme adopted for solving the technical problem, the automobile brake detection control system comprises a brake detection control device arranged on an automobile chassis, and further comprises a first pressure monitoring unit and a second pressure monitoring unit which are arranged in an automobile brake pedal, the extending end of the automobile brake pedal is connected with an automobile brake master cylinder piston through a brake pedal arm; the central controller is connected with the signal output ends of the first pressure monitoring unit and the second pressure monitoring unit through wires. The central controller is further connected with a brake lamp, an accelerator pedal reset device and a vehicle control unit through wires. The device is applied to kinetic energy recovery and brake control of the electric automobile.

Description

Technical Field

[0001] The utility model provides an electric vehicle kinetic energy recovery control system, belonging to the technical field of electric vehicle kinetic energy recovery control. Background Art

[0002] The braking energy recovery technology of electric vehicles refers to the control of the drive motor to operate as a generator while ensuring braking efficiency when excess energy is released during vehicle deceleration, braking or coasting. Through an energy conversion device connected to the drive shaft, a portion of the vehicle's mechanical energy (kinetic energy or potential energy) is converted into other forms of energy (electrical energy) and stored in the energy storage device for subsequent acceleration. When in use, the energy can be released quickly to achieve the purpose of recovering and utilizing braking energy and increasing the cruising range of electric vehicles.

[0003] The current kinetic energy recovery method is mainly to adjust the control ratio of kinetic energy recovery operation and mechanical brake operation by measuring the corresponding relationship of the displacement of the master brake cylinder piston or the displacement of the brake pedal, generally by measuring the rotation angle of the brake pedal or the displacement of the master brake cylinder piston. However, the disadvantage of this method is that it is necessary to change the proportional relationship between the brake pedal stroke and the braking force provided by the mechanical brake, that is, the intervention time of the mechanical brake. This is because there are many factors that affect kinetic energy recovery, such as the battery's ability to withstand maximum charging, and the ABS anti-lock braking system will intervene when the tire slip rate exceeds the set value. These parameters are dynamic and will affect the kinetic energy recovery strategy in real time, so it is difficult to maximize kinetic energy recovery, and it is difficult to achieve linear coordination when kinetic energy recovery and mechanical brake operation are coordinated, resulting in inconsistent linearity between the brake pedal stroke and the braking force output of the entire system; therefore, it is necessary to find a method that allows the driver to easily control the kinetic energy recovery intensity without increasing the brake stroke and changing the mechanical brake braking curve, so as to provide braking force according to the driver's needs and maximize kinetic energy recovery.

[0004] Specifically, when the kinetic energy recovery system is working, it will first adjust the strength of kinetic energy recovery according to the pressure applied by the driver to the master brake cylinder. The pressure sensor can be installed between the brake pedal and the master brake cylinder or between the brake pedal and the brake pedal arm or on the brake pedal arm to measure the deformation of the pedal arm, etc. It is used to measure the force applied by the driver to the mechanical brake system to adjust the kinetic energy recovery intensity. When the kinetic energy recovery force is at its maximum and still cannot meet the braking demand, the mechanical brake will be activated only after the braking force is increased. When the slip rate is too large, the anti-lock braking system will first reduce the strength of the mechanical brake and maximize the kinetic energy recovery. Another important point is that compared with the traditional method of measuring the displacement of the master brake cylinder, if the brake assist system fails, even if the brake pedal is pressed with great force, a sufficiently large master cylinder displacement effect cannot be generated, and the maximum kinetic energy recovery cannot be obtained, because the strength of the kinetic energy recovery is controlled by the displacement of the master cylinder, thereby increasing the safety hazard.

[0005] In addition, the kinetic energy recovery system currently used has the following defects:

[0006] (1) Currently, a brake switch is installed on the brake pedal fixing frame to sense the change in the angle of the brake pedal. When the brake pedal is rotated to the set angle, the brake switch closes and sends a closing signal to the controller, causing the controller to enter the kinetic energy recovery mode. The disadvantage of this control method is that the kinetic energy recovery force cannot be linearly controlled, because the brake switch outputs a switch signal and cannot output an analog signal. Therefore, the kinetic energy recovery force cannot be too large to avoid excessive impact on the vehicle, and it cannot provide the maximum kinetic energy recovery force.

[0007] (2) The driver's braking force is detected by measuring the travel of the brake pedal or the rotation angle of the pedal, thereby adjusting the strength of kinetic energy recovery. The fundamental disadvantage of this control method is that the two systems work in parallel. It is necessary to consider the power battery's ability to withstand energy recovery, and it cannot affect the work of the ABS. When the ABS starts the anti-lock braking action, the kinetic energy recovery operation must be exited, and the maximum kinetic energy recovery cannot be achieved.

[0008] (3) The purpose of the collaborative braking system is to dynamically adjust the distribution ratio of kinetic energy recovery and mechanical braking by detecting the power battery's ability to withstand kinetic energy recovery, so as to achieve maximum kinetic energy recovery without changing the ratio of braking force to pedal angle. However, there are many factors that affect the power battery's ability to withstand the maximum charging current, and the parameters are dynamically changing, so it is difficult to ensure a linear relationship between the changing stroke of the brake pedal and the braking torque output by the entire system. The driver feels that the brake output is not linear enough and the foot feel is inconsistent, affecting driving safety. The system also has a serious defect that if there is a problem with the brake assist operation, the driver cannot press the brake pedal to the bottom and cannot maximize kinetic energy recovery. Instead, it seriously affects the braking effect, increases the sliding distance, and thus increases safety hazards.

[0009] (4) The single-pedal control mode of electric vehicles determines the strength of kinetic energy recovery by detecting the release angle of the accelerator pedal. When the accelerator pedal is released, the kinetic energy recovery is maximized. However, the disadvantage of this system is that the driver can achieve the maximum kinetic energy recovery by releasing the accelerator pedal, which means a better braking effect. It can meet the braking requirements of some usage scenarios. However, if the accelerator pedal is used to control the deceleration and braking of the vehicle for a long time, the driver will rarely use the brake pedal. The braking force provided by kinetic energy recovery alone is difficult to meet the driving conditions. When encountering an emergency, the driver's reaction may be to step on the accelerator pedal all the way down, resulting in the vehicle losing control, which is the so-called brake failure accident. In addition, releasing the accelerator pedal to provide full kinetic energy recovery is not in line with driving habits. Utility Model Content

[0010] In order to overcome the deficiencies in the prior art, the utility model aims to solve the technical problem of providing an improvement in the hardware structure of a kinetic energy recovery control system for an electric vehicle.

[0011] In order to solve the above technical problems, the technical solution adopted by the utility model is: an electric vehicle kinetic energy recovery control system, comprising a brake detection control device arranged on a vehicle chassis, wherein a central controller is arranged inside the brake detection control device, and further comprising a first pressure monitoring unit and a second pressure monitoring unit arranged inside a vehicle brake pedal, wherein an extended end of the vehicle brake pedal is connected to a piston of a vehicle brake master cylinder through a brake pedal arm;

[0012] The central controller is connected to the signal output ends of the first pressure monitoring unit and the second pressure monitoring unit respectively through wires;

[0013] The central controller is also connected to the brake light, the accelerator pedal reset device, and the vehicle controller through wires. When in use, the central controller converts the received pressure signal into an analog signal and a switch signal and sends it to the vehicle controller for further processing;

[0014] The power input terminal of the central controller is connected to the power module.

[0015] The central controller is also connected to a control panel module via a wire, and the control panel module is used to send an analog signal for adjusting the pressure monitoring sensitivity.

[0016] The first pressure monitoring unit and the second pressure monitoring unit are fixed to the base plate of the automobile brake pedal after being buckled together. One end of the base plate is hinged to one end of the movable pedal through a hinge, so that the movable pedal can compress the first pressure monitoring unit and the second pressure monitoring unit on the base plate when being stepped on.

[0017] The first pressure monitoring unit and the second pressure monitoring unit specifically collect the force data applied by the driver to the car brake pedal, and send the collected force data to the central controller in real time. After analysis and processing by the brake detection control device, the control signal is sent to the vehicle controller to adjust the kinetic energy recovery force.

[0018] The chip model set inside the central controller is STM32F103C8T6;

[0019] The first pressure monitoring unit and the second pressure monitoring unit specifically adopt thin film varistors, model number is PGA301-Q1.

[0020] The beneficial effects of the present invention compared to the prior art are as follows: the present invention improves the existing kinetic energy recovery control system of electric vehicles, and installs a pressure monitoring unit on the brake pedal to measure the force applied by the driver on the brake pedal, thereby controlling the strength of kinetic energy recovery. This can achieve linear control of kinetic energy recovery and linear coordination of kinetic energy recovery and mechanical braking without changing the performance of mechanical brakes. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The utility model is further described below in conjunction with the accompanying drawings:

[0022] Figure 1 It is a schematic diagram of the circuit structure of the utility model;

[0023] Figure 2 This is a schematic diagram of the structure of the automobile brake system of the utility model;

[0024] Figure 3 This is a diagram showing the effect of a brake test on an existing brake system in an embodiment of the utility model;

[0025] Figure 4 This is a diagram showing the effect of a braking test on the improved braking system in the embodiment of the utility model;

[0026] In the figure: 1 is the central controller, 2 is the vehicle brake pedal, 3 is the vehicle brake master cylinder piston, 4 is the first pressure monitoring unit, 5 is the second pressure monitoring unit, 6 is the brake light, 7 is the accelerator pedal reset device, 10 is the vehicle controller, 11 is the power module, 21 is the brake pedal arm, and 22 is the control panel module. DETAILED DESCRIPTION

[0027] like Figure 1 and Figure 2 As shown, the utility model provides an electric vehicle kinetic energy recovery control system, comprising a brake detection control device arranged on a vehicle chassis, wherein a central controller 1 is arranged inside the brake detection control device, and further comprising a first pressure monitoring unit 4 and a second pressure monitoring unit 5 arranged inside a vehicle brake pedal 2, wherein the extended end of the vehicle brake pedal 2 is connected to a vehicle brake master cylinder piston 3 through a brake pedal arm 21;

[0028] The central controller 1 is connected to the signal output ends of the first pressure monitoring unit 4 and the second pressure monitoring unit 5 respectively through wires;

[0029] The central controller 1 is also connected to the brake light 6, the accelerator pedal reset device 7, and the vehicle controller 10 through wires. When in use, the central controller 1 converts the received pressure signal into an analog signal and a switch signal and sends it to the vehicle controller 10 for further processing;

[0030] The power input terminal of the central controller 1 is connected to the power module 11 .

[0031] The central controller 1 is also connected to a control panel module 22 via a wire, and the control panel module 22 is used to send an analog signal for adjusting the pressure monitoring sensitivity.

[0032] The first pressure monitoring unit 4 and the second pressure monitoring unit 5 are fixed to the bottom plate of the automobile brake pedal 2 after being buckled together, and one end of the bottom plate is hinged to one end of the movable pedal through a hinge, so that the movable pedal can compress the first pressure monitoring unit 4 and the second pressure monitoring unit 5 on the bottom plate when being stepped on.

[0033] The first pressure monitoring unit 4 and the second pressure monitoring unit 5 are specifically installed on the upper surface of the automobile brake pedal, and the collected force data applied by the driver to the brake pedal are sent to the central controller 1 in real time. After analysis and processing by the brake detection control device, the control signal is sent to the vehicle controller 10 to adjust the kinetic energy recovery force.

[0034] The chip model set inside the central controller 1 is STM32F103C8T6;

[0035] The first pressure monitoring unit 4 and the second pressure monitoring unit 5 specifically adopt thin film varistors, model PGA301-Q1.

[0036] The utility model provides an electric vehicle kinetic energy recovery control system, which relates to an electric vehicle series kinetic energy recovery brake system. Specifically, an operating brake detection control device is set to detect the force applied by the driver on the brake pedal in real time, so as to control the strength of kinetic energy recovery. The utility model installs an independent displacement sensor or pressure monitoring unit between the brake pedal and the brake master cylinder piston to measure the force applied by the driver to the brake pedal before the vehicle performs mechanical braking. The brake detection control device analyzes and processes the pressure data, and adjusts the kinetic energy recovery strength by measuring the physical quantity of pressure or pedal displacement, so that the kinetic energy recovery function of the vehicle can work independently, thereby allowing the kinetic energy recovery of the electric vehicle to work before the mechanical brake, rather than the two functions working at the same time.

[0037] Before use, the utility model can adjust the sensitivity of the signal through the control panel or the body controller. By setting two pressure monitoring units to work independently, two pressure monitoring signals can be provided to the control system. The central controller can monitor and amplify the pressure applied by the driver to the mechanical brake system. The central controller compares the two (redundant) signals, reads the sensitivity value set by the driver, and sends the processed signals to the vehicle controller for kinetic energy recovery control, thereby realizing safety monitoring of the system.

[0038] Furthermore, the utility model installs a pressure monitoring unit on the brake pedal or between the master cylinder piston and the brake pedal, connects the signal output end of the sensor to the brake detection control device, and after starting the control device, controls the kinetic energy recovery force by monitoring the force applied by the driver to the brake pedal. When the force applied by the driver to the brake pedal does not move the brake pedal to the closed position of the brake switch, that is, when the mechanical brake is not started, the kinetic energy recovery degree can be maximized. At the same time, the driver can adjust the kinetic energy recovery force by adjusting the force applied to the brake pedal.

[0039] The electric vehicle kinetic energy recovery control system provided by the utility model can not only realize the maximum kinetic energy recovery, but also maintain a linear relationship between the braking force output of the braking system and the travel of the brake pedal, thereby avoiding the safety hazard drivers caused by long-term use of the single-pedal mode; by setting a corresponding control system, the kinetic energy recovery can reach the maximum power even when the brake assist fails, thereby greatly shortening the braking distance of the electric vehicle and improving the safety performance of the vehicle.

[0040] In the embodiment of the utility model, a conventional braking system and an improved braking system are used to conduct a braking control experiment at the same time. The test vehicle speed is decelerated from 65km / h to 0km / h. The mass of the tested electric vehicle is 2t, the rated power of the motor is 40kw, the voltage is 338V, and the test conditions are the braking parameters when the brake assist is lost.

[0041] like Figure 3 As shown in the figure, under the control of the existing braking system, the red line is the braking starting line, the yellow line is the braking ending line, and the blue line is the maximum kinetic energy recovery current. The entire braking process takes 40 seconds, the maximum recovery current is 0.1771x100=17.1A, and the braking distance is 360 meters.

[0042] like Figure 4 As shown in the figure, under the control of the braking system provided by the utility model, the red line is the braking start line, the yellow line is the braking end line, and the blue line is the maximum kinetic energy recovery current. The entire braking process takes 15 seconds, the maximum recovery current is 0.685x100=68.5A, and the braking distance is 112 meters.

[0043] It can be seen that after the brake system is modified in the utility model, the maximum recovery power of the motor is 23kw, and the maximum recovery power of the original vehicle circuit is 5kw, which is increased by 360%. The braking distance of the original vehicle circuit is 360 meters, and the distance after modification is 112 meters, which reduces the braking distance by two-thirds. Compared with the existing electric vehicle braking system, the utility model has better kinetic energy recovery and braking effect.

[0044] Regarding the specific structure of the utility model, it should be explained that the connection relationship between the various component modules adopted in the utility model is definite and feasible. Except for special instructions in the embodiments, the specific connection relationship can bring corresponding technical effects and solve the technical problems raised by the utility model without relying on the execution of corresponding software programs. The components, modules, models of specific components and the connection methods between each other appearing in the utility model, as well as the conventional use methods and expected technical effects brought about by the above-mentioned technical features, except for specific instructions, all belong to the disclosed contents in patents, journal articles, technical manuals, technical dictionaries, and textbooks that can be obtained by technical personnel in this field before the application date, or belong to the existing technologies such as conventional technologies and common knowledge in this field, and there is no need to elaborate, so that the technical solution provided in this case is clear, complete and feasible, and the corresponding physical products can be reproduced or obtained according to the technical means.

[0045] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model, rather than to limit it. Although the utility model has been described in detail with reference to the aforementioned embodiments, ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not make the essence of the corresponding technical solution deviate from the scope of the technical solution of the embodiments of the utility model.

Claims

1. An electric vehicle kinetic energy recovery control system, comprising a brake detection control device arranged on a vehicle chassis, characterized in that: The brake detection control device is provided with a central controller (1) inside, and also includes a first pressure monitoring unit (4) and a second pressure monitoring unit (5) arranged inside a vehicle brake pedal (2); an extended end of the vehicle brake pedal (2) is connected to a vehicle brake master cylinder piston (3) via a brake pedal arm (21); The central controller (1) is connected to the signal output ends of the first pressure monitoring unit (4) and the second pressure monitoring unit (5) respectively through wires; The central controller (1) is also connected to the brake light (6), the accelerator pedal reset device (7), and the vehicle controller (10) respectively through wires. When in use, the central controller (1) converts the received pressure signal into an analog signal and a switch signal and sends the converted signal to the vehicle controller (10) for further processing. The power input terminal of the central controller (1) is connected to the power module (11).

2. The electric vehicle kinetic energy recovery control system according to claim 1, characterized in that: The central controller (1) is also connected to a control panel module (22) via a wire, and the control panel module (22) is used to send an analog signal for adjusting the pressure monitoring sensitivity.

3. The electric vehicle kinetic energy recovery control system according to claim 1, characterized in that: The first pressure monitoring unit (4) and the second pressure monitoring unit (5) are fixed to the bottom plate of the automobile brake pedal (2) after being buckled, and one end of the bottom plate is hinged to one end of the movable pedal via a hinge, so that the movable pedal can compress the first pressure monitoring unit (4) and the second pressure monitoring unit (5) on the bottom plate when being stepped on.

4. The electric vehicle kinetic energy recovery control system according to claim 3, characterized in that: The first pressure monitoring unit (4) and the second pressure monitoring unit (5) specifically collect force data applied by the driver to the vehicle brake pedal (2), and send the collected force data to the central controller (1) in real time. After analysis and processing by the brake detection control device, the control signal is sent to the vehicle controller (10) to adjust the kinetic energy recovery force.

5. The electric vehicle kinetic energy recovery control system according to claim 1, characterized in that: The chip model provided inside the central controller (1) is STM32F103C8T6; The first pressure monitoring unit (4) and the second pressure monitoring unit (5) specifically adopt thin film varistors, model PGA301-Q1.

Images