阅读说明：本技术 一种真空泵的控制方法及计算机可存储介质 (Control method of vacuum pump and computer-storable medium ) 是由 李晖 于 2020-05-27 设计创作，主要内容包括：本发明提供了一种真空泵的控制方法及计算机可存储介质,涉及电动汽车制动控制技术领域,通过确定真空泵的初始开启阈值与初始关闭阈值；采集真空泵的当前真空度并判断真空度与初始开启阈值的大小,若判断出真空度大于或等于初始开启阈值,流程结束,否则真空泵使能开启；当真空泵工作后真空泵内的真空度增加,且增加后的真空度小于或等于所述初始关闭阈值,则真空泵继续工作,否则真空泵关闭；当真空泵继续工作且增加后的真空度的变化率小于预设值并持续一定时间,则真空泵进入饱和度自学习模式。通过本发明解决了真空泵超负荷工作,导致真空泵内热积累,温度过高造成真空泵烧毁的问题,提高了真空泵的使用寿命。(The invention provides a control method of a vacuum pump and a computer-storable medium, which relate to the technical field of brake control of electric automobiles, and are characterized in that an initial opening threshold and an initial closing threshold of the vacuum pump are determined; acquiring the current vacuum degree of the vacuum pump and judging the vacuum degree and the initial starting threshold value, finishing the process if the vacuum degree is judged to be greater than or equal to the initial starting threshold value, otherwise enabling the vacuum pump to be started; when the vacuum degree in the vacuum pump is increased after the vacuum pump works and the increased vacuum degree is less than or equal to the initial closing threshold value, the vacuum pump continues to work, otherwise, the vacuum pump is closed; and when the vacuum pump continues to work and the change rate of the increased vacuum degree is smaller than a preset value and lasts for a certain time, the vacuum pump enters a saturation self-learning mode. The invention solves the problems of heat accumulation in the vacuum pump and burnout of the vacuum pump caused by overhigh temperature due to the overload work of the vacuum pump, and improves the service life of the vacuum pump.)

1. A method of controlling a vacuum pump, comprising the steps of:

step 1, determining a first opening threshold and a first closing threshold of a vacuum pump according to an atmospheric pressure value, a vehicle speed and a brake pedal depth;

step 2, acquiring the current vacuum degree of the vacuum pump through a vacuum pressure sensor, judging the current vacuum degree and the first starting threshold value, finishing the process if the current vacuum degree is greater than or equal to the first starting threshold value, otherwise enabling the vacuum pump to be started, and entering step 3;

step 3, acquiring the current vacuum degree of the vacuum pump through a vacuum pressure sensor, judging the current vacuum degree and the first closing threshold value, if the current vacuum degree is greater than the first closing threshold value, closing the vacuum pump, otherwise, continuing to work, and entering step 4;

step 4, when the change rate of the current vacuum degree in the vacuum pump is smaller than a first preset value and lasts for a certain time, the vacuum pump enters a saturation self-learning mode, namely, the first opening threshold and the first closing threshold of the vacuum pump are adaptively adjusted, specifically:

setting the current vacuum degree in the vacuum pump as a second closing threshold value of the vacuum pump, taking the second closing threshold value as a new first closing threshold value, wherein the second closing threshold value is not lower than a second preset value, subtracting a third preset value from the second closing threshold value to obtain a second opening threshold value, taking the second opening threshold value as a new first opening threshold value, and wherein the second opening threshold value is not lower than a fourth preset value;

the first preset value is any value between 0.2kpa and 0.7kpa, the second preset value is any value between-35 kpa and-45 kpa, the third preset value is any value between 15kpa and 20kpa, and the fourth preset value is any value between-25 kpa and-35 kpa.

2. The method for controlling a vacuum pump according to claim 1, wherein when the change rate of the current vacuum degree in the vacuum pump in the step 4 is greater than or equal to the first preset value, it is determined that the vacuum degree is not saturated, the saturation self-learning mode fails, and the vacuum pump enters an overload protection process, wherein the overload protection process specifically comprises:

and if the actual working times of the vacuum pump exceed the preset working times, the vacuum pump is closed, otherwise, the vacuum pump continues to work until the actual working times of the vacuum pump exceed the preset working times.

3. The control method of a vacuum pump according to claim 2, wherein the calculation formula of the actual number of times of operation of the vacuum pump is:

T＝(T_on*f₁)-(T_off*f₂)

wherein T represents the number of times the vacuum pump is operated, T_onRepresenting the vacuum pump on time, f₁Indicating the frequency, T, of the vacuum pump opening count_offRepresenting the vacuum pump off time, f₂Representing the frequency of vacuum pump shut-downs.

4. The method for controlling a vacuum pump according to claim 1, wherein the first activation threshold is calculated by the formula:

P_on＝P₀+P_von+P_brkon

wherein, P_onDenotes a first opening threshold, P₀Indicating the vacuum pump opening threshold, P, adjusted according to atmospheric pressure_vonRepresents a vacuum pump turn-on threshold adjusted according to vehicle speed; p_brkonRepresents a vacuum pump turn-on threshold adjusted according to the brake pedal depth;

the calculation formula of the first closing threshold value is as follows:

P_off＝P₁+P_voff+P_brkof

wherein, P_offDenotes a first closing threshold, P₁Indicating a vacuum pump shut-off threshold, P, adjusted according to atmospheric pressure_voffRepresents a vacuum pump shut-off threshold adjusted according to vehicle speed; p_brkofRepresenting a vacuum pump shut-off threshold that is adjusted according to brake pedal depth.

5. A computer-readable storage medium, characterized in that the computer-readable storage medium stores a program which, when being executed by a processor, is able to carry out the steps of the method of controlling a vacuum pump according to any one of claims 1 to 4.

Technical Field

The invention relates to the technical field of electric automobile brake control, in particular to a control method of a vacuum pump and a computer-readable storage medium.

Background

The vacuum boosting effect of the electric automobile brake system relates to the running safety of an automobile, and in the automobile brake boosting system, the boosting effect of the brake system is poor due to the fact that a vacuum booster cannot obtain vacuum or the obtained vacuum is insufficient. The vacuum pump is used as a power assisting device of an electric automobile brake system, and the acting force of the input rod is amplified and then acts on the brake master cylinder through the output rod in the braking process, so that the braking force is increased, and the fatigue strength of a driver is reduced. Because the pure electric vehicle is not provided with the air inlet manifold, air inlet work cannot be adopted to generate pressure, and therefore power assisting is achieved. The electronic vacuum pump performs work through air suction of the motor so as to form vacuum in the cavity, and in the braking process, assistance is generated through pressure difference of the front cavity and the rear cavity.

As disclosed in chinese patent application No. CN109484387A, "a method and a system for controlling a vacuum pump of an electric vehicle" collects external ambient atmospheric pressure by presetting a correspondence table of a relationship between the ambient atmospheric pressure and the vacuum chamber pressure, and determines a required vacuum chamber pressure according to the correspondence table; collecting the current vacuum cavity pressure, and controlling the vacuum pump to operate to increase the pressure of the vacuum cavity when the current vacuum cavity pressure is less than the required vacuum cavity pressure until the current vacuum cavity pressure reaches the required vacuum cavity pressure; and collecting the pressure of a brake pedal, calculating the brake output pressure of the vacuum booster according to the pressure of the brake pedal, and controlling the vacuum pump to operate until the pressure of the vacuum cavity is gradually increased to the brake output pressure if the brake output pressure is greater than the current vacuum cavity pressure. The intelligent control method and the intelligent control system can improve the intelligence of the vacuum pump control and improve the safety and convenience of the electric automobile.

The control method can realize the control of the vacuum pump and the control of the vacuum pump under different altitudes. However, when air leakage occurs in the vacuum pump, the vacuum degree in the vacuum pump cannot reach the vacuum pump closing threshold value, so that the vacuum pump works for a long time, heat accumulation in the vacuum pump occurs, the vacuum pump is burnt due to overhigh temperature, the braking effect is influenced, and even safety risks occur.

Therefore, it is necessary to develop a control method of a vacuum pump and a computer-readable storage medium.

Disclosure of Invention

In view of the above, the present invention provides a control method for a vacuum pump and a computer-readable medium for solving the technical problems of heat accumulation in the vacuum pump and burnout of the vacuum pump due to an overload operation of the vacuum pump.

In a first aspect, the present invention provides a method for controlling a vacuum pump, comprising the steps of:

step 1, determining a first opening threshold and a first closing threshold of a vacuum pump according to an atmospheric pressure value, a vehicle speed and a brake pedal depth;

step 2, acquiring the current vacuum degree of the vacuum pump through a vacuum pressure sensor, judging the current vacuum degree and the first starting threshold value, finishing the process if the current vacuum degree is greater than or equal to the first starting threshold value, otherwise enabling the vacuum pump to be started, and entering step 3;

step 3, acquiring the current vacuum degree of the vacuum pump through a vacuum pressure sensor, judging the current vacuum degree and the first closing threshold value, if the current vacuum degree is greater than the first closing threshold value, closing the vacuum pump, otherwise, continuing to work, and entering step 4;

step 4, when the change rate of the current vacuum degree in the vacuum pump is smaller than a first preset value and lasts for a certain time, the vacuum pump enters a saturation self-learning mode, namely, the first opening threshold and the first closing threshold of the vacuum pump are adaptively adjusted, specifically:

setting the current vacuum degree in the vacuum pump as a second closing threshold value of the vacuum pump, taking the second closing threshold value as a new first closing threshold value, wherein the second closing threshold value is not lower than a second preset value, subtracting a third preset value from the second closing threshold value to obtain a second opening threshold value, taking the second opening threshold value as a new first opening threshold value, and wherein the second opening threshold value is not lower than a fourth preset value;

the first preset value is any value between 0.2kpa and 0.7kpa, the second preset value is any value between-35 kpa and-45 kpa, the third preset value is any value between 15kpa and 20kpa, and the fourth preset value is any value between-25 kpa and-35 kpa.

Further, when the change rate of the current vacuum degree in the vacuum pump in the step 4 is greater than or equal to the first preset value, it is determined that the vacuum degree is not saturated, the saturation self-learning mode fails, and the vacuum pump enters an overload protection process, where the overload protection process specifically includes:

and if the actual working times of the vacuum pump exceed the preset working times, the vacuum pump is closed, otherwise, the vacuum pump continues to work until the actual working times of the vacuum pump exceed the preset working times.

Further, the calculation formula of the actual working times of the vacuum pump is as follows:

T＝(T_on*f₁)-(T_off*f₂)

wherein T represents the number of times the vacuum pump is operated, T_onRepresenting the vacuum pump on time, f₁Indicating the frequency, T, of the vacuum pump opening count_offRepresenting the vacuum pump off time, f₂Representing the frequency of vacuum pump shut-downs.

Further, in step 1, the calculation formula of the first opening threshold is as follows:

P_on＝P₀+P_von+P_brkon

wherein, P_onDenotes a first opening threshold, P₀Indicating the vacuum pump opening threshold, P, adjusted according to atmospheric pressure_vonRepresents a vacuum pump turn-on threshold adjusted according to vehicle speed; p_brkonRepresents a vacuum pump turn-on threshold adjusted according to the brake pedal depth;

the calculation formula of the first closing threshold value is as follows:

P_off＝P₁+P_voff+P_brkof

wherein, P_offDenotes a first closing threshold, P₁Indicating a vacuum pump shut-off threshold, P, adjusted according to atmospheric pressure_voffRepresents a vacuum pump shut-off threshold adjusted according to vehicle speed; p_brkofRepresenting a vacuum pump shut-off threshold that is adjusted according to brake pedal depth.

In a second aspect, the invention also provides a computer readable storage medium storing a program executable by a processor to implement the steps of the method of controlling a vacuum pump according to the invention.

The invention brings the following beneficial effects:

by the control method of the vacuum pump and the computer-storable medium, the control of the vacuum pump under different altitudes is realized, the problems that the vacuum pump is overloaded to work, heat is accumulated in the vacuum pump, the temperature is overhigh and the vacuum pump is finally burnt due to the fact that the vacuum degree acquired by the vacuum pressure sensor is over-limit or the vacuum pump leaks air are solved, and the service life of the vacuum pump is prolonged.

Drawings

FIG. 1 is a flow chart of a method for controlling a vacuum pump according to the present invention;

FIG. 2 is a logic flow diagram of an embodiment of the present invention.

Detailed Description

The invention will be further explained with reference to the drawings.

As shown in fig. 1, the method for controlling a vacuum pump according to the present invention includes the following steps:

step 1, determining a first opening threshold and a first closing threshold of a vacuum pump according to an atmospheric pressure value, a vehicle speed and a brake pedal depth;

step 2, acquiring the current vacuum degree of the vacuum pump through a vacuum pressure sensor, judging the current vacuum degree and the first starting threshold value, finishing the process if the current vacuum degree is greater than or equal to the first starting threshold value, otherwise enabling the vacuum pump to be started, and entering step 3;

step 3, acquiring the current vacuum degree of the vacuum pump through a vacuum pressure sensor, judging the current vacuum degree and the first closing threshold value, if the current vacuum degree is greater than the first closing threshold value, closing the vacuum pump, otherwise, continuing to work, and entering step 4;

step 4, when the change rate of the current vacuum degree in the vacuum pump is smaller than a first preset value and lasts for a certain time, the vacuum pump enters a saturation self-learning mode, namely, the first opening threshold and the first closing threshold of the vacuum pump are adaptively adjusted, specifically:

setting the current vacuum degree in the vacuum pump as a second closing threshold value of the vacuum pump, taking the second closing threshold value as a new first closing threshold value, wherein the second closing threshold value is not lower than a second preset value, subtracting a third preset value from the second closing threshold value to obtain a second opening threshold value, taking the second opening threshold value as a new first opening threshold value, and wherein the second opening threshold value is not lower than a fourth preset value;

the first preset value is any value between 0.2kpa and 0.7kpa, the second preset value is any value between-35 kpa and-45 kpa, the third preset value is any value between 15kpa and 20kpa, and the fourth preset value is any value between-25 kpa and-35 kpa.

Specifically, since the vacuum pump is usually controlled to be turned on and off by using a threshold value strategy, after the vehicle is powered on, if it is detected that the vacuum degree acquired by the vacuum pressure sensor of the vacuum pump at that time is less than a first turning threshold value of the vacuum pump, the vacuum pump is enabled to be turned on, and a calculation formula of the first turning threshold value is represented as:

P_on＝P₀+P_von+P_brkon

wherein, P_onIndicating a first vacuum pump activation threshold, P₀Indicating the vacuum pump opening threshold, P, adjusted according to atmospheric pressure_vonRepresents a vacuum pump turn-on threshold adjusted according to vehicle speed; p_brkonRepresenting the vacuum pump turn-on threshold adjusted according to the brake pedal depth.

The first shutdown threshold is calculated as:

P_off＝P₁+P_voff+P_brkof

wherein, P_offDenotes a first closing threshold, P₁Indicating a vacuum pump shut-off threshold, P, adjusted according to atmospheric pressure_voffRepresents a vacuum pump shut-off threshold adjusted according to vehicle speed; p_brkofRepresenting a vacuum pump shut-off threshold that is adjusted according to brake pedal depth.

Specifically, when the vacuum pump continues to operate and the rate of change of the current vacuum level at that time is less than the first preset value (0.5 kpa as an example in the present embodiment), the vacuum pump enters the saturation self-learning mode. Wherein, the calculation formula of the change rate of the vacuum degree is expressed as:

ΔP＝(P₃-P₄)/(t₁-t₂)

wherein Δ P represents the rate of change in vacuum, P₃Represents t₁Vacuum degree at time P₄Represents t₂The vacuum degree at the time.

In this embodiment, as shown in fig. 2, after the vacuum pump enters the saturation self-learning mode, the vacuum pump is considered to be saturated at this time, the enabling of the vacuum pump is stopped, and the opening and closing thresholds of the vacuum pump are adaptively adjusted. Namely, the current vacuum degree collected after working for a certain time is set as the second closing threshold value of the vacuum pump to replace the first closing threshold value initially set according to the atmospheric pressure value, the vehicle speed and the depth of the brake pedal. And the opening threshold value in the self-learning mode is changed along with the change of the opening threshold value, and the second opening threshold value is obtained by subtracting a third preset value from the second closing threshold value and is used for replacing the first opening threshold value. Meanwhile, in order to prevent the closing threshold value of the vacuum pump in the saturation self-learning mode from being too low in the case of serious leakage, the lowest value of the second closing threshold value and the second opening threshold value is limited, the second closing threshold value is required to be not lower than a second preset value, and the second opening threshold value is required to be not lower than a fourth preset value, wherein the second preset value is any value between-35 kpa and-45 kpa, the third preset value is any value between 15kpa and 20kpa, and the fourth preset value is any value between-25 kpa and-35 kpa. The second preset value is ideally-40 kpa and the fourth preset value is ideally-30 kpa as measured by the engineer in combination with the test environment.

When the vacuum degree collected by the vacuum pressure sensor exceeds the limit or the vacuum pump leaks, the change rate of the vacuum degree in the vacuum pump is always in a state of being larger than or equal to the first preset value, the vacuum degree is judged to be in an unsaturated state, namely the saturation self-learning mode fails, and at the moment, the vacuum pump enters an overload protection process. And judging the state of the vacuum pump in closing or working by judging the actual working times and the preset working times of the vacuum pump in the overload protection process. The preset working times of the vacuum pump are changed according to different models of vacuum pumps manufactured by different manufacturers and experimental environments. When the vacuum pump works for a certain time, the working frequency of the vacuum pump is recorded once, and when the vacuum pump stops working for a certain time, the working frequency of the vacuum pump is reduced once. If the calculated actual working times of the vacuum pump exceed the preset working times, the overload mark in the overload protection process of the vacuum pump points to the position 1, namely the vacuum pump is closed; when the actual working times of the vacuum pump do not exceed the preset working times, the overload mark in the overload protection process of the vacuum pump points to the position 0, and at the moment, the vacuum pump continues to work until the working times of the vacuum pump exceed the preset working times. Wherein the calculation formula of the actual working times of the vacuum pump is

T＝(T_on*f₁)-(T_off*f₂)

Wherein T represents the number of times of vacuum pump operation, T_onRepresenting the vacuum pump on time, f₁Indicating the frequency, T, of the vacuum pump opening count_offRepresenting the vacuum pump off time, f₂Representing the frequency of vacuum pump shut-downs.

In the present embodiment, a computer-readable storage medium stores a program executable by a processor to implement the steps of the control method of the vacuum pump according to the present invention.

The functions, if implemented in the form of software functional units and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present invention may be embodied in the form of a software product, which is stored in a storage medium and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present invention. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk, and other various media capable of storing program codes. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.