Control method and system of automobile electronic vacuum pump

Abstract

The invention provides a control method of an automobile electronic vacuum pump. The control method comprises the following steps: continuously monitoring a vacuum pressure value in a vacuum tank; controlling the electronic vacuum pump by using the basic strategy; continuously monitoring the continuous operation time of the electronic vacuum pump, controlling the electronic vacuum pump to stop when the electronic vacuum pump continuously operates to a first preset time, and storing the ultimate vacuum pressure value; after second preset time, whether pressure leakage occurs or not is judged; if the judgment result is yes, an alarm signal is sent out; and if the judgment result is no, when the ratio of the vacuum pressure value in the vacuum tank to the limit vacuum pressure value is smaller than or equal to a first preset ratio, the electronic vacuum pump is controlled to be started, and when the ratio of the vacuum pressure value in the vacuum tank to the limit vacuum pressure value is larger than or equal to a second preset ratio, the electronic vacuum pump is controlled to be stopped. The control method can avoid long-time operation of the electronic vacuum pump so as to prolong the service life. The invention further provides a control system for implementing the control method.

Description

Technical Field

[0001] This invention relates to the field of automotive technology, and in particular to a control method and system for an automotive electronic vacuum pump. Background Technology

[0002] Modern cars are equipped with brake assist systems. Conventional gasoline vehicles use a vacuum source provided by the engine for assistance, while electric vehicles lack a vacuum source and require an electronic vacuum pump (EVP) to provide an auxiliary vacuum. Currently, electric vehicles control the vacuum pump by collecting signals from a vacuum pressure sensor on the vacuum tank. When the vehicle is driving in high-altitude areas, the thin atmosphere causes the vacuum pump to run continuously, affecting its lifespan. Summary of the Invention

[0003] The purpose of this invention is to provide a control method for an automotive electronic vacuum pump, which can automatically adjust the operating strategy of the electronic vacuum pump according to the ambient atmospheric pressure, thereby avoiding prolonged operation and extending its service life.

[0004] Another objective of this invention is to provide a control system for an automotive electronic vacuum pump that can automatically adjust the operating strategy of the electronic vacuum pump according to the ambient atmospheric pressure, thereby avoiding prolonged operation and extending its service life.

[0005] This invention provides a control method for an automotive electronic vacuum pump, wherein the electronic vacuum pump is connected to a vacuum tank, and the control method for the automotive electronic vacuum pump includes: S10: Continuously monitor the vacuum pressure value inside the vacuum tank; S20: The electronic vacuum pump is controlled using a basic strategy, which is the control strategy for the normal operation of the electronic vacuum pump in a plain environment. S30: Continuously monitors the continuous running time of the electronic vacuum pump. When the electronic vacuum pump runs continuously for a first preset time, it controls the electronic vacuum pump to stop and saves the current vacuum pressure value in the vacuum tank as an ultimate vacuum pressure value. The first preset time is greater than the maximum continuous running time of the electronic vacuum pump in a plain environment. S40: After a second preset time has elapsed since the control electronic vacuum pump stopped, determine whether pressure leakage has occurred; If the result of S40 is yes, then proceed to S50: issue an alarm signal; If the result of S40 is negative, proceed to S60: when the ratio of the vacuum pressure value in the vacuum tank to the ultimate vacuum pressure value is less than or equal to a first preset ratio, control the electronic vacuum pump to start; when the ratio of the vacuum pressure value in the vacuum tank to the ultimate vacuum pressure value is greater than or equal to a second preset ratio, control the electronic vacuum pump to stop.

[0006] The control method for an automotive electronic vacuum pump provided by this invention controls the pump using a basic strategy under normal conditions, and monitors the vacuum pressure value inside the vacuum tank and the continuous operating time of the electronic vacuum pump. When the vehicle is traveling in high-altitude areas, the thin atmosphere causes changes in the continuous operating time of the electronic vacuum pump. The operating strategy of the electronic vacuum pump is then automatically adjusted based on the continuous operating time to avoid prolonged continuous operation and extend the pump's lifespan. Furthermore, this control method for an automotive electronic vacuum pump only requires a single sensor to collect the vacuum pressure value inside the vacuum tank, further reducing costs.

[0007] In another illustrative embodiment of the control method for an automotive electronic vacuum pump, in S20, the basic strategy is: when the vacuum pressure value in the vacuum tank is greater than or equal to -50 kPa, the electronic vacuum pump is controlled to start; when the vacuum pressure value in the vacuum tank is less than or equal to -75 kPa, the electronic vacuum pump is controlled to stop.

[0008] In another illustrative embodiment of the control method for an automotive electronic vacuum pump, S40 includes: S41: Save the vacuum pressure value inside the vacuum tank after a second preset time, which is 2 seconds; S42: Calculate the rate of increase of the vacuum pressure inside the vacuum container within a second preset time period based on the ultimate vacuum pressure value; and S43: If the rate of increase of the vacuum pressure value in the vacuum tank within the second preset time is less than 2 kPa / s, it is determined that no pressure leakage has occurred; if the rate of increase of the vacuum pressure value in the vacuum tank within the second preset time is greater than or equal to 2 kPa / s and less than 5 kPa / s, it is determined to be a minor pressure leakage; if the rate of increase of the vacuum pressure value in the vacuum tank within the second preset time is greater than or equal to 5 kPa / s, it is determined to be a severe pressure leakage.

[0009] In another illustrative embodiment of the control method for an automotive electronic vacuum pump, in S50, if a slight pressure leak occurs, only an alarm signal is issued; if a severe pressure leak occurs, both an alarm signal and a vehicle power limiting signal are issued simultaneously.

[0010] In another illustrative embodiment of the control method for an automotive electronic vacuum pump, in S30, when the electronic vacuum pump runs continuously for a first preset time, if a limit vacuum pressure value already exists, the limit vacuum pressure value is updated to the current vacuum pressure value in the vacuum tank.

[0011] In another illustrative embodiment of the control method for an automotive electronic vacuum pump, in S30, the first preset time is 15 seconds; in S60, the first preset ratio is 60%, and the second preset ratio is 85%.

[0012] This invention also provides a control system for an automotive electronic vacuum pump, wherein the electronic vacuum pump is connected to a vacuum tank. The control system for the automotive electronic vacuum pump includes a vacuum pressure sensor and a controller. The vacuum pressure sensor is capable of measuring the vacuum pressure value inside the vacuum tank. The controller is connected to a vacuum pressure sensor and an electronic vacuum pump. The controller is configured to continuously monitor the vacuum pressure inside the vacuum tank via the vacuum pressure sensor and to control the electronic vacuum pump using a basic strategy—a control strategy for normal operation of the electronic vacuum pump in a flat environment. The controller is also configured to continuously monitor the continuous operating time of the electronic vacuum pump. When the electronic vacuum pump has been running continuously for a first preset time, the controller stops the electronic vacuum pump and saves the current vacuum pressure inside the vacuum tank as a limit vacuum pressure value. The first preset time is greater than the maximum continuous operating time of the electronic vacuum pump in a flat environment. After a second preset time has elapsed since the electronic vacuum pump was stopped, the controller determines whether a pressure leak has occurred. If the determination is yes, the controller issues an alarm signal. If the determination is no, the controller starts the electronic vacuum pump when the ratio of the vacuum pressure inside the vacuum tank to the limit vacuum pressure value is less than or equal to a first preset ratio, and stops the electronic vacuum pump when the ratio is greater than or equal to a second preset ratio.

[0013] In another illustrative implementation of the control system for an automotive electronic vacuum pump, the basic strategy is as follows: when the vacuum pressure inside the vacuum tank is greater than or equal to -50 kPa, the electronic vacuum pump is started; when the vacuum pressure inside the vacuum tank is less than or equal to -75 kPa, the electronic vacuum pump is stopped.

[0014] In another illustrative embodiment of the control system of the automotive electronic vacuum pump, the controller is configured to save the vacuum pressure value inside the vacuum tank after a second preset time, the second preset time being 2 seconds, and calculate the rate of increase of the vacuum pressure value inside the vacuum tank within the second preset time in conjunction with the ultimate vacuum pressure value. If the rate of increase of the vacuum pressure value inside the vacuum tank within the second preset time is greater than or equal to 2 kPa / s and less than 5 kPa / s, it is judged as a slight pressure leak; if the rate of increase of the vacuum pressure value inside the vacuum tank within the second preset time is greater than or equal to 5 kPa / s, it is judged as a severe pressure leak.

[0015] In another illustrative embodiment of the control system for an automotive electronic vacuum pump, the controller is configured to issue only an alarm signal if a minor pressure leak occurs, and to issue both an alarm signal and a vehicle power limiting signal if a severe pressure leak occurs.

[0016] In another illustrative embodiment of the control system for an automotive electronic vacuum pump, the controller is configured to update the ultimate vacuum pressure value to the current vacuum pressure value in the vacuum tank if an ultimate vacuum pressure value already exists when the electronic vacuum pump has been running continuously for a first preset time.

[0017] In another illustrative embodiment of the control system of the automotive electronic vacuum pump, the first preset time is 15 seconds; the first preset ratio is 60% and the second preset ratio is 85%. Attached Figure Description

[0018] The following figures are for illustrative purposes only and do not limit the scope of the invention.

[0019] Figure 1 This is a flowchart illustrating one implementation of a control method for an automotive electronic vacuum pump.

[0020] Figure 2 This is a schematic diagram illustrating an implementation method for controlling an automotive electronic vacuum pump.

[0021] Figure 3 This is a partial flowchart of the control method for an automotive electronic vacuum pump.

[0022] Label Explanation 10. Electronic vacuum pump 20 Vacuum Tanks 30 Vacuum booster 40 Vacuum Pressure Sensor 50 Controllers. Detailed Implementation

[0023] To provide a clearer understanding of the technical features, objectives, and effects of the invention, specific embodiments of the invention are now described with reference to the accompanying drawings. In the drawings, the same reference numerals indicate components with the same or similar structures but the same function.

[0024] In this document, “illustrative” means “serving as an example, illustration or description”, and any illustration or implementation described herein as “illustrative” should not be construed as a more preferred or advantageous technical solution.

[0025] To keep the drawings simple, each drawing only schematically shows the parts related to the present invention, and they do not represent the actual structure of the product.

[0026] Figure 1 This is a flowchart illustrating one implementation of a control method for an automotive electronic vacuum pump. Figure 2 This is a schematic diagram illustrating an implementation method for controlling an automotive electronic vacuum pump. (Refer to...) Figure 1 and Figure 2Electric vehicles typically employ a vacuum booster system as the braking system's power source. This system includes an electronic vacuum pump 10, a vacuum tank 20, and a vacuum booster 30, all interconnected. The electronic vacuum pump 10 generates a vacuum source, the vacuum tank 20 stores the vacuum source generated by the pump 10, and the vacuum booster 30 utilizes the vacuum source stored in the tank 20 to provide power to the braking system. The control method for the automotive electronic vacuum pump includes the following steps S10 to S60.

[0027] Step S10: Continuously monitor the vacuum pressure value inside the vacuum tank 20. (Refer to...) Figure 2 In an illustrative embodiment, a vacuum pressure sensor 40 is used to measure the vacuum pressure value inside the vacuum tank 20, and a controller 50 continuously reads the measurement signal from the vacuum pressure sensor 40 to achieve continuous monitoring of the vacuum pressure value inside the vacuum tank 20. The vacuum pressure sensor 40 can be installed in the vacuum tank 20 or in a pipe or cavity connected to the vacuum tank 20, such as in the cavity connected to the vacuum tank 20 inside the vacuum booster 30.

[0028] Step S20: Control the electronic vacuum pump 10 using a basic strategy, which is the control strategy for the normal operation of the electronic vacuum pump 10 in a plain environment. For example, if the atmospheric pressure in a plain environment is 100 kPa, the basic strategy is: when the vacuum pressure value inside the vacuum tank 20 is greater than or equal to -50 kPa, control the electronic vacuum pump 10 to start; when the vacuum pressure value inside the vacuum tank 20 is less than or equal to -75 kPa, control the electronic vacuum pump 10 to stop. In the illustrative embodiment, the controller 50 sends a control signal to the electronic vacuum pump 10 using the basic strategy.

[0029] Step S30: Continuously monitor the continuous operating time of the electronic vacuum pump 10. When the electronic vacuum pump 10 has been running continuously for a first preset time, control the electronic vacuum pump 10 to stop and save the current vacuum pressure value in the vacuum tank 20 as an ultimate vacuum pressure value. The first preset time is greater than the maximum continuous operating time of the electronic vacuum pump 10 in a plain environment. For example, the maximum continuous operating time of the electronic vacuum pump 10 in a plain environment is usually 8 seconds. Therefore, in the illustrative embodiment, the first preset time is set to 15 seconds.

[0030] Step S40: After a second preset time has elapsed since the control electronic vacuum pump 10 stopped, determine whether a pressure leak has occurred. The second preset time is set to 2 seconds.

[0031] If the result of step S40 is yes, then proceed to step S50: issue an alarm signal.

[0032] If the result of step S40 is negative, proceed to step S60: when the ratio of the vacuum pressure value in the vacuum tank 20 to the ultimate vacuum pressure value is less than or equal to a first preset ratio, control the electronic vacuum pump 10 to start; when the ratio of the vacuum pressure value in the vacuum tank 20 to the ultimate vacuum pressure value is greater than or equal to a second preset ratio, control the electronic vacuum pump 10 to stop.

[0033] In the illustrative embodiment, the first preset ratio is 60%, and the second preset ratio is 85%. For example, when the ultimate vacuum pressure is collected as -60 kPa, the electronic vacuum pump 10 is started when the vacuum pressure inside the vacuum tank 20 is greater than or equal to -36 kPa, and stopped when the vacuum pressure inside the vacuum tank 20 is less than or equal to -51 kPa. By dynamically adjusting the operating strategy of the electronic vacuum pump 10 through proportional relationships, even when atmospheric pressure decreases, the situation where the electronic vacuum pump 10 runs for a long time because it cannot reach the pressure threshold can be avoided.

[0034] The control method for an automotive electronic vacuum pump provided by this invention controls the pump using a basic strategy under normal conditions, and monitors the vacuum pressure value inside the vacuum tank and the continuous operating time of the electronic vacuum pump. When the vehicle is traveling in high-altitude areas, the thin atmosphere causes changes in the continuous operating time of the electronic vacuum pump. The operating strategy of the electronic vacuum pump is then automatically adjusted based on the continuous operating time to avoid prolonged continuous operation and extend the pump's lifespan. Furthermore, this control method for an automotive electronic vacuum pump only requires a single sensor to collect the vacuum pressure value inside the vacuum tank, further reducing costs.

[0035] In an illustrative embodiment, in step S30, when the electronic vacuum pump 10 has been running continuously for a first preset time, if a limit vacuum pressure value already exists, the limit vacuum pressure value is updated to the current vacuum pressure value within the vacuum tank 20. This allows the operating strategy of the electronic vacuum pump 10 to be dynamically updated based on the actual environment as the vehicle continues to travel to higher altitudes.

[0036] Figure 3 This is a partial flowchart of the control method for an automotive electronic vacuum pump. (Refer to...) Figure 3 Step S40 specifically includes the following steps S41 to S43.

[0037] Step S41: After the second preset time, save the vacuum pressure value inside the vacuum tank 20.

[0038] Step S42: Calculate the rate of increase of the vacuum pressure value inside the vacuum container 20 within the second preset time period based on the ultimate vacuum pressure value. Specifically, the rate of increase of the vacuum pressure value inside the vacuum container 20 is calculated by dividing the pressure difference between the vacuum container 20 before and after the second preset time period by the second preset time period.

[0039] Step S43: If the rate of increase of the vacuum pressure value inside the vacuum tank 20 within the second preset time is less than 2 kPa / s, it is determined that no pressure leakage has occurred. If the rate of increase of the vacuum pressure value inside the vacuum tank 20 within the second preset time is greater than or equal to 2 kPa / s and less than 5 kPa / s, it is determined to be a minor pressure leakage. If the rate of increase of the vacuum pressure value inside the vacuum tank 20 within the second preset time is greater than or equal to 5 kPa / s, it is determined to be a major pressure leakage. Correspondingly, in step S50, if a minor pressure leakage occurs, only an alarm signal is issued; if a major pressure leakage occurs, both an alarm signal and a vehicle power limiting signal are issued simultaneously to reduce the vehicle power and ensure the safety of people and vehicles.

[0040] This invention also provides a control system for an automotive electronic vacuum pump, used to implement the aforementioned control method for the automotive electronic vacuum pump. (Refer to...) Figure 2 The control system of the automotive electronic vacuum pump includes a vacuum pressure sensor 40 and a controller 50. The vacuum pressure sensor 40 measures the vacuum pressure value within the vacuum tank 20. In an illustrative embodiment, the vacuum pressure sensor 40 is located within the vacuum tank 20; however, it is not limited to this. In other illustrative embodiments, the vacuum pressure sensor 40 may also be located in a pipe or cavity communicating with the vacuum tank 20, such as within the cavity communicating with the vacuum tank 20 in the vacuum booster 30. The controller 50 is signal-connected to the vacuum pressure sensor 40 and the electronic vacuum pump 10. In an illustrative embodiment, the controller 50 is a vehicle controller.

[0041] The controller 50 is configured to continuously monitor the vacuum pressure value inside the vacuum tank 20 via the vacuum pressure sensor 40, and to control the electronic vacuum pump 10 using a basic strategy. The controller 50 is also configured to continuously monitor the continuous operating time of the electronic vacuum pump 10, and to control the electronic vacuum pump 10 to stop when it has been running continuously for a first preset time, saving the current vacuum pressure value inside the vacuum tank 20 as an ultimate vacuum pressure value. In an illustrative embodiment, the first preset time is 15 seconds.

[0042] After a second preset time has elapsed since the start of the controlled electronic vacuum pump 10, the controller 50 determines whether a pressure leak has occurred. If the determination is yes, the controller 50 issues an alarm signal. If the determination is no, i.e., no pressure leak has occurred, the controller 50 starts the electronic vacuum pump 10 when the ratio of the vacuum pressure value to the ultimate vacuum pressure value in the vacuum tank 20 is less than or equal to a first preset ratio, and stops the electronic vacuum pump 10 when the ratio is greater than or equal to a second preset ratio. In the illustrative embodiment, the first preset ratio is 60%, and the second preset ratio is 85%. In the illustrative implementation, the basic strategy is as follows: when the vacuum pressure value inside the vacuum tank 20 is greater than or equal to -50 kPa, the electronic vacuum pump 10 is started; when the vacuum pressure value inside the vacuum tank 20 is less than or equal to -75 kPa, the electronic vacuum pump 10 is stopped.

[0043] In an illustrative embodiment, the controller 50 is configured to update the ultimate vacuum pressure value to the current vacuum pressure value within the vacuum tank 20 if an ultimate vacuum pressure value already exists when the electronic vacuum pump 10 has been running continuously for a first preset time. This allows the ultimate vacuum pressure value to be dynamically updated according to the actual environment as the vehicle continues to travel to higher altitudes, thus adjusting the operating strategy of the electronic vacuum pump 10.

[0044] In an illustrative embodiment, the controller 50 is configured to save the vacuum pressure value inside the vacuum tank 20 after a second preset time, which is 2 seconds, and calculate the rate of increase of the vacuum pressure value inside the vacuum tank 20 within the second preset time in conjunction with the ultimate vacuum pressure value. If the rate of increase of the vacuum pressure value inside the vacuum tank 20 within the second preset time is greater than or equal to 2 kPa / s and less than 5 kPa / s, it is determined to be a minor pressure leak. If the rate of increase of the vacuum pressure value inside the vacuum tank 20 within the second preset time is greater than or equal to 5 kPa / s, it is determined to be a major pressure leak. The controller 50 is configured to issue only an alarm signal if a minor pressure leak occurs, and to issue both an alarm signal and a vehicle power limiting signal if a major pressure leak occurs.

[0045] It should be understood that although this specification is described according to various embodiments, not every embodiment contains only one independent technical solution. This way of describing the specification is only for clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

[0046] The detailed descriptions listed above are merely specific descriptions of feasible embodiments of the present invention and are not intended to limit the scope of protection of the present invention. All equivalent implementation schemes or modifications made without departing from the spirit of the present invention, such as combinations, divisions or repetitions of features, should be included within the scope of protection of the present invention.

Claims

1. A control method for an automotive electronic vacuum pump, wherein the electronic vacuum pump is connected to a vacuum tank, characterized in that, The control method for the automotive electronic vacuum pump includes: S10: Continuously monitor the vacuum pressure value inside the vacuum tank; S20: Control the electronic vacuum pump using a basic strategy, which is the control strategy for the normal operation of the electronic vacuum pump in a plain environment; S30: Continuously monitor the continuous running time of the electronic vacuum pump, and control the electronic vacuum pump to stop when the electronic vacuum pump runs continuously for a first preset time, and save the current vacuum pressure value in the vacuum tank as an ultimate vacuum pressure value. The first preset time is greater than the maximum continuous running time of the electronic vacuum pump in a plain environment. S40: After a second preset time has elapsed since the electronic vacuum pump was stopped, determine whether a pressure leak has occurred; If the result of S40 is yes, then proceed to S50: issue an alarm signal; If the result of S40 is negative, proceed to S60: when the ratio of the vacuum pressure value in the vacuum tank to the ultimate vacuum pressure value is less than or equal to a first preset ratio, control the electronic vacuum pump to start; when the ratio of the vacuum pressure value in the vacuum tank to the ultimate vacuum pressure value is greater than or equal to a second preset ratio, control the electronic vacuum pump to stop.

2. The control method for an automotive electronic vacuum pump as described in claim 1, characterized in that, In S20, the basic strategy is as follows: when the vacuum pressure value in the vacuum tank is greater than or equal to -50 kPa, the electronic vacuum pump is controlled to start; when the vacuum pressure value in the vacuum tank is less than or equal to -75 kPa, the electronic vacuum pump is controlled to stop.

3. The control method for an automotive electronic vacuum pump as described in claim 1, characterized in that, S40 includes: S41: Save the vacuum pressure value inside the vacuum tank after the second preset time, where the second preset time is 2 seconds; S42: Calculate the rate of increase of the vacuum pressure value inside the vacuum tank within the second preset time period based on the ultimate vacuum pressure value; and S43: If the rate of increase of the vacuum pressure value inside the vacuum tank within the second preset time is less than 2 kPa / s, it is determined that no pressure leakage has occurred; if the rate of increase of the vacuum pressure value inside the vacuum tank within the second preset time is greater than or equal to 2 kPa / s and less than 5 kPa / s, it is determined to be a slight pressure leakage; if the rate of increase of the vacuum pressure value inside the vacuum tank within the second preset time is greater than or equal to 5 kPa / s, it is determined to be a severe pressure leakage.

4. The control method for an automotive electronic vacuum pump as described in claim 3, characterized in that, In the S50, if a minor pressure leak occurs, only an alarm signal will be issued; if a major pressure leak occurs, both an alarm signal and a vehicle power limit signal will be issued simultaneously.

5. The control method for an automotive electronic vacuum pump as described in claim 1, characterized in that, In S30, when the electronic vacuum pump runs continuously for the first preset time, if the ultimate vacuum pressure value already exists, the ultimate vacuum pressure value is updated to the current vacuum pressure value inside the vacuum tank.

6. The control method for an automotive electronic vacuum pump as described in claim 1, characterized in that, In S30, the first preset time is 15 seconds; in S60, the first preset ratio is 60%, and the second preset ratio is 85%.

7. A control system for an automotive electronic vacuum pump, wherein the electronic vacuum pump is connected to a vacuum tank, characterized in that, The control system of the automotive electronic vacuum pump includes: A vacuum pressure sensor (40) capable of measuring the vacuum pressure value inside the vacuum tank; and A controller (50) is signal-connected to the vacuum pressure sensor (40) and the electronic vacuum pump. The controller (50) is configured to continuously monitor the vacuum pressure value inside the vacuum tank via the vacuum pressure sensor (40), and to control the electronic vacuum pump using a basic strategy, which is a control strategy for the normal operation of the electronic vacuum pump in a plain environment. The controller (50) is also configured to continuously monitor the continuous operating time of the electronic vacuum pump, and when the electronic vacuum pump has been running continuously for a first preset time, to control the electronic vacuum pump to stop, and to save the current vacuum pressure value inside the vacuum tank as a limit vacuum pressure value. The first preset time is greater than the maximum continuous operating time of the electronic vacuum pump in a plain environment, and after the controller (50) controls the electronic vacuum pump to stop for a second preset time, it determines whether a pressure leak occurs. If the determination result is yes, the controller (50) issues an alarm signal. If the determination result is no, the controller (50) controls the electronic vacuum pump to start when the ratio of the vacuum pressure value in the vacuum tank to the ultimate vacuum pressure value is less than or equal to a first preset ratio, and controls the electronic vacuum pump to stop when the ratio of the vacuum pressure value in the vacuum tank to the ultimate vacuum pressure value is greater than or equal to a second preset ratio.

8. The control system of the automotive electronic vacuum pump as described in claim 7, characterized in that, The basic strategy is as follows: when the vacuum pressure inside the vacuum tank is greater than or equal to -50 kPa, the electronic vacuum pump is started; when the vacuum pressure inside the vacuum tank is less than or equal to -75 kPa, the electronic vacuum pump is stopped.

9. The control system for the automotive electronic vacuum pump as described in claim 7, characterized in that, The controller (50) is configured to save the vacuum pressure value inside the vacuum tank after a second preset time of 2 seconds, and to calculate the rate of increase of the vacuum pressure value inside the vacuum tank within the second preset time in conjunction with the ultimate vacuum pressure value. If the rate of increase of the vacuum pressure value inside the vacuum tank within the second preset time is greater than or equal to 2 kPa / s and less than 5 kPa / s, it is judged as a slight pressure leak; if the rate of increase of the vacuum pressure value inside the vacuum tank within the second preset time is greater than or equal to 5 kPa / s, it is judged as a severe pressure leak.

10. The control system of the automotive electronic vacuum pump as described in claim 9, characterized in that, The controller (50) is configured to issue only an alarm signal if a minor pressure leak occurs, and to issue both an alarm signal and a vehicle power limit signal if a severe pressure leak occurs.

11. The control system of the automotive electronic vacuum pump as described in claim 7, characterized in that, The controller (50) is configured to update the ultimate vacuum pressure value to the current vacuum pressure value inside the vacuum tank if the ultimate vacuum pressure value already exists when the electronic vacuum pump has been running continuously for the first preset time.

12. The control system for the automotive electronic vacuum pump as described in claim 7, characterized in that, The first preset time is 15 seconds; the first preset ratio is 60%; and the second preset ratio is 85%.

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