CN113635883B - Environmental pressure detection system and method for vacuum boosting system of electric automobile - Google Patents
Environmental pressure detection system and method for vacuum boosting system of electric automobile Download PDFInfo
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- CN113635883B CN113635883B CN202111005669.6A CN202111005669A CN113635883B CN 113635883 B CN113635883 B CN 113635883B CN 202111005669 A CN202111005669 A CN 202111005669A CN 113635883 B CN113635883 B CN 113635883B
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
- B60T17/00—Component parts, details, or accessories of power brake systems not covered by groups B60T8/00, B60T13/00 or B60T15/00, or presenting other characteristic features
- B60T17/18—Safety devices; Monitoring
- B60T17/22—Devices for monitoring or checking brake systems; Signal devices
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
- B60R16/00—Electric or fluid circuits specially adapted for vehicles and not otherwise provided for; Arrangement of elements of electric or fluid circuits specially adapted for vehicles and not otherwise provided for
- B60R16/02—Electric or fluid circuits specially adapted for vehicles and not otherwise provided for; Arrangement of elements of electric or fluid circuits specially adapted for vehicles and not otherwise provided for electric constitutive elements
- B60R16/023—Electric or fluid circuits specially adapted for vehicles and not otherwise provided for; Arrangement of elements of electric or fluid circuits specially adapted for vehicles and not otherwise provided for electric constitutive elements for transmission of signals between vehicle parts or subsystems
- B60R16/0231—Circuits relating to the driving or the functioning of the vehicle
- B60R16/0232—Circuits relating to the driving or the functioning of the vehicle for measuring vehicle parameters and indicating critical, abnormal or dangerous conditions
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
- B60T17/00—Component parts, details, or accessories of power brake systems not covered by groups B60T8/00, B60T13/00 or B60T15/00, or presenting other characteristic features
Abstract
The invention belongs to the technical field of vacuum boosting systems, and discloses an environment pressure detection system and method of an electric automobile vacuum boosting system. According to the invention, the environmental pressure sensor is integrated in the control unit of the whole vehicle, so that the environmental pressure sensor is not easy to damage, and does not need to be subjected to electrical fault detection.
Description
Technical Field
The invention relates to the technical field of vacuum boosting systems, in particular to an environmental pressure detection system and method of an electric automobile vacuum boosting system.
Background
The vacuum boosting system is usually configured in a brake system of the electric automobile, and during braking, the intervention time of the vacuum boosting system not only affects the safety of vehicle braking, but also affects the comfort of vehicle braking, and has important influence on the driving experience.
Environmental pressure is an important parameter that influences the opportunity that vacuum servo system intervenes, if environmental pressure detection is inaccurate or the sensor breaks down, will influence vehicle security and travelling comfort to a great extent, still can influence the life-span of vehicle electric vacuum pump. Therefore, the vehicle can be ensured to accurately and stably detect the environmental pressure, and the method has great significance for ensuring the safety of the vehicle and the service life of the electric vacuum pump.
In the prior art, an environmental pressure sensor is usually externally connected to a vehicle control unit, when the environmental pressure sensor is subjected to fault diagnosis, only electric fault detection is performed, the reliability is low, and when the environmental pressure sensor fails, the reliable operation of a vehicle braking system cannot be ensured.
Disclosure of Invention
The invention aims to provide an environmental pressure detection system and method of an electric automobile vacuum boosting system, which improve the reliability of fault detection of an environmental pressure sensor and can ensure the reliable operation of a vehicle braking system when the environmental pressure sensor fails.
In order to achieve the purpose, the invention adopts the following technical scheme:
an environmental pressure detection system of an electric vehicle vacuum assist system, comprising:
the brake vacuum booster is communicated with the brake device through a hydraulic pipeline;
a vacuum sensor capable of measuring a vacuum level of an air chamber of the brake vacuum booster;
the vacuum air storage tank is communicated with the air chamber;
the electric vacuum pump is communicated with the vacuum air storage tank;
the one-way valve is arranged on a communication pipeline of the electric vacuum pump and the vacuum air storage tank;
the brake pedal is connected to a push rod of the brake vacuum booster;
a brake switch capable of detecting whether the brake pedal is depressed;
a brake controller capable of measuring a master cylinder pressure value of the brake device;
the whole vehicle control unit is internally provided with an environmental pressure sensor, the vacuum degree sensor, the electric vacuum pump, the brake switch, the environmental pressure sensor and the brake controller are respectively and electrically connected with the whole vehicle control unit, the whole vehicle control unit is internally stored with atmospheric pressure value data corresponding to the altitude, the atmospheric pressure value collected by the environmental pressure sensor is a first pressure value, the atmospheric pressure value obtained by calculation of the altitude positioned by the whole vehicle control unit through the positioning module is a second pressure value, the whole vehicle control unit can periodically compare the first pressure value with the second pressure value, when the difference value of the first pressure value and the second pressure value is greater than a first limit value, the whole vehicle control unit records a reliability error once, and in a set driving cycle, when the recorded times of the reliability error is greater than a second limit value, the whole vehicle control unit judges that the environmental pressure sensor has a reliability fault.
Preferably, the brake switch comprises a main body brake switch and an auxiliary brake switch, and the vehicle control unit determines whether the brake pedal is pressed according to the difference of the received switch signals of the main body brake switch and the auxiliary brake switch.
Preferably, the main body brake switch is a normally open switch, and the auxiliary brake switch is a normally closed switch.
Preferably, the whole vehicle control unit can update the atmospheric pressure value data corresponding to the altitude in a networking mode.
The environmental pressure detection method for the vacuum power-assisted system of the electric automobile comprises the following steps:
the whole vehicle control unit acquires a first pressure value through an environmental pressure sensor;
the whole vehicle control unit calculates a second pressure value through the altitude positioned by the positioning module;
the whole vehicle control unit compares the first pressure value with the second pressure value, and when the difference value between the first pressure value and the second pressure value is larger than a limit value, a reliability error is recorded once;
and in a set driving cycle, when the number of times of reliability errors recorded by the whole vehicle control unit is greater than a limit value, judging that the reliability fault exists in the environmental pressure sensor.
Preferably, when the difference value between the first pressure value and the second pressure value is not greater than the limit value, the whole vehicle control unit takes the first pressure value as an ambient pressure value to control the electric vacuum pump to act.
Preferably, when the difference value between the first pressure value and the second pressure value is larger than the limit value, the whole vehicle control unit takes the second pressure value as an ambient pressure value to control the action of the electric vacuum pump.
Preferably, the brake switch comprises a main body brake switch and an auxiliary brake switch, and the vehicle control unit determines that the brake pedal is pressed when the switch signals of the main body brake switch and the auxiliary brake switch received by the vehicle control unit are the same.
Preferably, when the switch signals of the main brake switch and the auxiliary brake switch received by the vehicle control unit are different, whether the brake pedal is depressed or not is determined by a master cylinder pressure value detected by the brake controller.
Preferably, the vehicle control unit divides the difference value between the first pressure value and the second pressure value by the second pressure value to obtain a deviation percentage, and records a reliability error once when the deviation percentage exceeds a limit amount.
The invention has the beneficial effects that:
in the environmental pressure detection system of the vacuum power-assisted system of the electric automobile, the environmental pressure sensor is integrated in the control unit of the whole automobile, so that the environmental pressure sensor is not easy to damage and does not need to be subjected to electrical fault detection.
The environmental pressure detection system of the vacuum power-assisted system of the electric automobile can detect the difference faults of the brake switch, increases the coverage range of the diagnosis strategy of the brake switch, and further improves the safety and the reliability of the brake system.
Drawings
FIG. 1 is a schematic structural diagram of an ambient pressure detection system of a vacuum assist system of an electric vehicle according to an embodiment of the present invention;
fig. 2 is a flowchart of an environmental pressure detection method of a vacuum assist system of an electric vehicle according to an embodiment of the present invention.
In the figure:
1. braking the vacuum booster; 2. a vacuum degree sensor; 3. a vacuum gas storage tank; 4. an electric vacuum pump; 5. a one-way valve; 6. a brake pedal; 7. a brake switch; 8. a brake controller; 9. and a vehicle control unit.
Detailed Description
Reference will now be made in detail to the embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the same or similar parts throughout, or parts having the same or similar functions. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention.
In the description of the present invention, unless otherwise specifically stated or limited, the terms "connected," "connected," and "fixed" are to be construed broadly and may include, for example, fixed or detachable connections, mechanical or electrical connections, direct or indirect connections via intermediate media, communication between two elements, or the interaction between two elements. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.
In the description of the present invention, unless otherwise expressly specified or limited, the first feature "on" or "under" the second feature may include the first feature and the second feature being in direct contact, or may include the first feature and the second feature being in contact not directly but with another feature therebetween. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly under and obliquely below the second feature, or simply meaning that the first feature is at a lesser elevation than the second feature.
The technical scheme of the invention is further explained by the specific implementation mode in combination with the attached drawings.
Example one
As shown in FIG. 1, the invention provides an environmental pressure detection system of an electric vehicle vacuum power-assisted system, which comprises a brake vacuum booster 1, a vacuum degree sensor 2, a vacuum air storage tank 3, an electric vacuum pump 4, a one-way valve 5, a brake pedal 6, a brake switch 7, a brake controller 8 and a vehicle control unit 9. Wherein, the brake vacuum booster 1 is communicated with the brake device through a hydraulic pipeline, the vacuum degree sensor 2 can measure the vacuum degree of an air chamber of the brake vacuum booster 1, the vacuum air storage tank 3 is communicated with the air chamber, the electric vacuum pump 4 is communicated with the vacuum air storage tank 3, the one-way valve 5 is arranged on a communication pipeline of the electric vacuum pump 4 and the vacuum air storage tank 3, the brake pedal 6 is connected with a push rod of the brake vacuum booster 1, the brake switch 7 can detect whether the brake pedal 6 is treaded down, the brake controller 8 can measure a main cylinder pressure value of the brake device, an environmental pressure sensor for detecting the external atmospheric pressure in real time is arranged in the vehicle control unit 9, the vacuum degree sensor 2, the electric vacuum pump 4, the brake switch 7, the environmental pressure sensor and the brake controller 8 are respectively and electrically connected with the vehicle control unit 9, the whole vehicle control unit 9 stores atmospheric pressure value data corresponding to altitude, the atmospheric pressure value collected by the ambient pressure sensor is a first pressure value, the atmospheric pressure value obtained by calculation of the altitude positioned by the whole vehicle control unit 9 through the positioning module is a second pressure value, the whole vehicle control unit 9 can periodically compare the first pressure value with the second pressure value, when the difference value of the first pressure value and the second pressure value is greater than a limit value, the whole vehicle control unit 9 records a reliability error once, and in a set driving cycle, when the recorded reliability error times are greater than the limit value, the whole vehicle control unit 9 judges that the ambient pressure sensor has reliability faults.
In the invention, the environmental pressure sensor is integrated in the whole vehicle control unit 9, so that the environmental pressure sensor is not easy to damage, and does not need to be subjected to electrical fault detection, when the environmental pressure sensor is detected, the atmospheric pressure value corresponding to the altitude at the current position is corrected to judge whether the reliability error and the reliability fault exist, so that the environmental pressure sensor can work really and reliably, and when the reliability error exists, the atmospheric pressure value corresponding to the altitude at the current position can be used as the environmental pressure value to control the action of the electric vacuum pump 4, so that the reliable operation of a vehicle braking system is ensured.
Specifically, the data acquisition period of the entire vehicle control unit 9 is 10 to 50ms to stabilize the reliability of data acquisition and the power consumption of data acquisition processing.
More specifically, the vehicle control unit 9 acquires a first pressure value measured by the ambient pressure sensor at a cycle of 50ms, and calculates a second pressure value at a cycle of 50ms by using the altitude positioned by the positioning module, that is, the vehicle control unit 9 compares the first pressure value with the second pressure value at a cycle of 50 ms.
Specifically, be equipped with the sensor that is used for detecting the vacuum in the vacuum gas holder 3, whole car control unit 9 collects vacuum in the vacuum gas holder 3, opens with the electric vacuum pump 4 of inside storage and closes the threshold and compare, if satisfy the threshold requirement, then open the vacuum booster pump, when the vacuum degree surpassed the threshold, closed electric vacuum pump 4, electric vacuum pump 4 opened and closed the threshold and carries out periodic adjustment according to the ambient pressure value.
In this embodiment, whole car the control unit 9 can the networking update with the atmospheric pressure value data that the altitude corresponds, the k value of the inside storage of whole car the control unit 9, can carry out periodic update through the OTA function, when detecting the credibility error of ambient pressure, the first pressure value that this driving cycle will be abandoned to the ambient pressure sensor and gathered, the second pressure value that uses the calculation to obtain replaces, when whole car the control unit 9 reports the credibility trouble of ambient pressure, can indicate to overhaul ambient pressure sensor, and proofread the k value of the inside storage of whole car the control unit 9 simultaneously.
Specifically, electric vacuum pump 4 can take out the air in the vacuum gas holder 3, makes it reach certain vacuum, because be provided with check valve 5 on the pipeline between electric vacuum pump 4 and the vacuum gas holder 3, so the air can only flow to electric vacuum pump 4 by in the vacuum gas holder 3, can prevent vacuum loss effectively, reduces electric vacuum pump 4's operating time, promotes life. The braking device is a common caliper brake of the vehicle and is controlled by a braking controller 8, the braking controller 8 is a common ABS controller or ESP controller in the vehicle and is communicated with a whole vehicle control unit 9 through a CAN bus, the braking controller 8 is integrated with a main cylinder pressure sensor, a main cylinder pressure value of the braking device is detected through the main cylinder pressure sensor, the whole vehicle control unit 9 is communicated with a positioning module through the CAN bus, and the positioning module is a GPS module and other existing modules capable of detecting the real-time position of the vehicle.
More specifically, the entire vehicle control unit 9 includes a hardware layer, a bottom layer software, and an application layer software. The invention mainly comprises a hardware layer, an application layer software and an operation processing module, wherein the hardware layer is used for receiving the voltage of pins of external accessories such as a sensor and a switch and outputting the voltage externally, the bottom layer software comprises logic for mutual conversion between the voltage signal and a digital or analog signal, the application layer software is mainly divided into a preprocessing module and an operation processing module, the preprocessing module is internally provided with signal checking and error processing logic, and the operation processing module is stored with a finished automobile control key algorithm and the like.
Specifically, the brake switch 7 includes a main brake switch and an auxiliary brake switch, and the vehicle control unit 9 determines whether the brake pedal 6 is pressed according to the difference of the received switch signals of the main brake switch and the auxiliary brake switch. The main body brake switch and the auxiliary brake switch are mutually verified, the accuracy of state detection of the brake pedal 6 is further guaranteed, and when the main body brake switch and the auxiliary brake switch simultaneously send signals for treading the brake pedal 6, the whole vehicle control unit 9 judges that the brake pedal 6 is treaded.
More specifically, the main body brake switch is a normally open switch for determining the state of the brake pedal 6, and the auxiliary brake switch is a normally closed switch for performing calibration and correction with the main body brake switch. The hardware layer of the vehicle control unit 9 detects the level changes of the main brake switch and the auxiliary brake switch and then uploads the level changes to the bottom layer software, the bottom layer software effectively converts the pin levels of the main brake switch and the auxiliary brake switch into digital signals 0/1 according to the internally stored threshold values and the processing logics high and low and uploads the digital signals to the preprocessing module of the application layer software, the preprocessing module checks the signals of the main brake switch and the auxiliary brake switch after receiving the signals, if the signals are consistent, the main brake switch signals are not processed and are directly transmitted to the operation processing module, and if the main brake switch signals are inconsistent with the auxiliary brake switch signals, the difference errors of the primary brake switch 7 are recorded.
In this embodiment, when a difference error of the brake switch 7 is detected, the main body brake switch signal is not used as the state of the brake switch 7, and the main cylinder pressure value transmitted by the brake controller 8 is used for judgment, and after the hardware layer of the vehicle control unit 9 receives the brake main cylinder pressure signal transmitted by the brake controller 8 on the CAN bus, the brake main cylinder pressure signal is uploaded to the preprocessing module of the application layer software through the bottom layer software. The preprocessing module stores a threshold value of the master cylinder pressure of the braking device, and when the master cylinder pressure value is larger than the threshold value, the whole vehicle control unit 9 judges that the brake pedal 6 is stepped on at the moment and is used for replacing the state of the brake switch 7 when the difference of the brake switch 7 is wrong.
Specifically, the master cylinder pressure threshold of the braking device can be adjusted according to different vehicle types, and can be updated from the cloud.
More specifically, a threshold value of the difference error frequency of the brake switch 7 is stored in the vehicle control unit 9, when the recorded difference error frequency of the brake switch 7 reaches the threshold value, the vehicle control unit 9 reports the difference fault of the brake switch 7, and the control instrument prompts a driver to repair the brake pedal 6 and the brake switch 7. The environmental pressure detection system of the vacuum power-assisted system of the electric automobile can detect the difference faults of the brake switch 7, increases the coverage range of the diagnosis strategy of the brake switch 7, and further improves the safety and the reliability of the brake system.
In this embodiment, when the vehicle control unit 9 detects that the brake pedal 6 is pressed down, and considers that the driver has a braking behavior, the vehicle control unit controls the brake vacuum booster 1 according to the vacuum degree in the brake vacuum booster 1 and the opening/closing threshold of the electric vacuum pump 4 stored inside, and the specific flow is as follows:
a vacuum degree sensor 2 arranged on an air chamber of the brake vacuum booster 1 detects the vacuum degree in the air chamber and then transmits the vacuum degree to an operation processing module of application layer software through a hardware layer and bottom layer software of a whole vehicle control unit 9.
The opening and closing threshold of the electric vacuum pump 4 under the standard condition obtained from the test is stored in the whole vehicle control unit 9, after the vacuum degree signal obtained by the vacuum degree sensor 2 is compared with the threshold, whether the electric vacuum pump 4 needs to be opened or not can be obtained, and the whole vehicle control unit 9 outputs a control signal of the electric vacuum pump 4 according to the control signal.
The opening and closing threshold of the electric vacuum pump 4 is adjusted according to different atmospheric pressures, the corresponding relation between the threshold and the atmospheric pressure value is stored in the whole vehicle control unit 9, the opening and closing threshold of the electric vacuum pump 4 is obtained by looking up a table according to a first pressure value acquired by the environmental pressure sensor, and when the whole vehicle control unit 9 detects that the reliability of the environmental pressure sensor is wrong, the opening and closing threshold of the electric vacuum pump 4 is obtained by looking up a table according to a second pressure value obtained by calculating the altitude positioned by the positioning module.
In this embodiment, the entire vehicle control unit 9 stores therein data of correspondence between atmospheric pressure values and altitudes obtained through experiments, and the correspondence between altitude and atmospheric pressure refers to an atmospheric pressure calculation formula:
P＝kP 0 (5.3788H 2 10 -9 -1.1975H10 -4 +1)
where k is an empirical coefficient, typically 1,P 0 Is standard atmospheric pressure and H is altitude.
In addition to the above formula, the atmospheric pressure at the corresponding altitude may be calculated by other approximate formulas, which are not limited herein, and the different formulas correspond to different limiting values of the difference between the first pressure value and the second pressure value.
In this embodiment, for different areas, the values of k are different, and are obtained according to a test and stored in the vehicle control unit 9, and when the area where the vehicle is located changes, the area can be identified by the positioning module, and the value of k is corrected, so as to ensure the accuracy of calculating the ambient pressure value.
Specifically, the atmospheric pressure is not only related to the altitude, but also affected by local temperature, climate, etc., and may be different for different areas and the same altitude, so that calibration needs to be performed based on the atmospheric pressure calculation formula. The type of function between altitude and atmospheric pressure is still substantially the same for different regions, and therefore a coefficient that varies with region is added before the empirical formula.
According to the invention, the ground surface area is divided according to the grid shape according to the difference of longitude and latitude of different areas, each grid corresponds to a unique experience coefficient k, a typical city can be selected from the grid, and the typical city is obtained by calculation according to the relation between the atmospheric pressure and the altitude published by the urban meteorological department.
In order to improve the accuracy of the second pressure value calculated by the vehicle control unit 9 through the altitude positioned by the positioning module, the mesh division can be made as fine as possible, but because the internal storage space of the vehicle control unit 9 is limited, the fineness of the mesh division and the accuracy of the second pressure value need to be chosen according to the actual situation.
Example two
As shown in fig. 2, the present embodiment provides an environmental pressure detection method of a vacuum boosting system of an electric vehicle based on a first embodiment, and specifically adopts the environmental pressure detection system of the vacuum boosting system of the electric vehicle in the first embodiment, which includes the following steps:
and step S101, starting the pre-inspection by the vehicle control unit 9.
In this step, after the entire vehicle control unit 9 wakes up, the ambient pressure sensor starts to work, and the entire vehicle control unit 9 reads the record times of the reliability error of the ambient pressure sensor from the memory, compares the record times with the threshold value of the reliability error times of the ambient pressure sensor, and determines whether the reliability fault of the ambient pressure sensor exists before the entire vehicle control unit 9 sleeps for the last time.
And if the reliability fault exists, the first pressure value acquired by the environmental pressure sensor is not used, the second pressure value acquired by calculating the altitude positioned by the positioning module is used as the environmental pressure value, and the reliability fault is reported.
And if the reliability fault does not exist, the next step is carried out.
Step S102, the vehicle control unit 9 acquires a first pressure value through the environmental pressure sensor.
In this step, the ambient pressure sensor performs operation, and the entire vehicle control unit 9 takes a pressure value acquired by the ambient pressure sensor as a first pressure value.
Step S103, the vehicle control unit 9 calculates a second pressure value through the altitude positioned by the positioning module.
In this step, the entire vehicle control unit 9 obtains the longitude and latitude where the vehicle is currently located from the message sent by the positioning module, determines the altitude of the current position and the empirical coefficient k in the atmospheric pressure calculation formula according to the area division stored inside the entire vehicle control unit 9, and then the entire vehicle control unit 9 calculates the obtained pressure value as the second pressure value according to the obtained empirical coefficient k and the altitude of the current position and the atmospheric pressure empirical formula.
And step S104, the whole vehicle control unit 9 compares the first pressure value with the second pressure value, and when the difference value between the first pressure value and the second pressure value is larger than a first limit value, a reliability error is recorded once.
In this step, the maximum threshold of the difference between the first pressure value and the second pressure value, that is, the threshold of the first limit value, is stored in the vehicle control unit 9, and when the difference between the first pressure value and the second pressure value is not greater than the first limit value, the vehicle control unit 9 controls the electric vacuum pump 4 to operate by taking the first pressure value as an ambient pressure value; when the difference value between the first pressure value and the second pressure value is greater than the first limit value, the vehicle control unit 9 records a reliability error once, stores the reliability error into the memory, and controls the electric vacuum pump 4 to act by taking the second pressure value as an ambient pressure value.
In this step, the entire vehicle control unit 9 divides the difference between the first pressure value and the second pressure value by the second pressure value to obtain a deviation percentage, and records a reliability error when the deviation percentage exceeds a limit amount, that is, the limit value of the difference between the first pressure value and the second pressure value changes according to the difference between the second pressure values, and in addition, a constant limit value can be set.
And S105, judging that the reliability fault exists in the environmental pressure sensor when the reliability error frequency recorded by the whole vehicle control unit 9 is greater than a second limit value in the set driving cycle.
In this step, the vehicle control unit 9 determines whether the reliability error recording number of times of the ambient pressure sensor exceeds a reliability error threshold, and if so, reports a reliability fault and prompts a driver to repair the ambient pressure sensor.
After the environmental pressure sensor is detected and one of the first pressure value and the second pressure value is determined to be selected as the environmental pressure value to control the electric vacuum pump 4 to act, in the running process of the vehicle, as the brake switch 7 specifically comprises a main body brake switch and an auxiliary brake switch, the whole vehicle control unit 9 judges the state of the brake pedal 6 through the main body brake switch and the auxiliary brake switch, and the specific judgment steps are as follows:
step S201, the vehicle control unit 9 receives the switching signals of the main brake switch and the auxiliary brake switch.
Step S202, the vehicle control unit 9 compares the difference between the switching signal sent by the main brake switch and the switching signal sent by the auxiliary brake switch.
Step S203, when the switch signal sent by the main body brake switch is the same as the switch signal sent by the auxiliary brake switch, the whole vehicle control unit 9 judges that the brake pedal 6 is treaded, and when the switch signal sent by the main body brake switch is different from the switch signal sent by the auxiliary brake switch, the whole vehicle control unit 9 judges whether the brake pedal 6 is treaded according to the main cylinder pressure value detected by the brake controller 8.
Specifically, after the driver depresses the brake pedal 6, the states of the main body brake switch and the auxiliary brake switch are simultaneously changed, and when the switch signal sent by the main body brake switch and the switch signal sent by the auxiliary brake switch are the same, the entire vehicle control unit 9 determines that the brake pedal 6 is depressed.
In this step, a threshold value of the difference error frequency of the brake switch 7 is stored in the vehicle control unit 9, when a switch signal sent by the main brake switch is different from a switch signal sent by the auxiliary brake switch, the vehicle control unit 9 records the difference error of the brake switch 7 once, and determines whether the brake pedal 6 is stepped on by using a master cylinder pressure value detected by the brake controller 8, and when the recorded difference error frequency of the brake switch 7 reaches the threshold value, the vehicle control unit 9 reports that the difference fault exists in the brake switch 7, and the control instrument prompts a driver to overhaul the brake pedal 6 and the brake switch 7.
When it is determined whether the brake pedal 6 is depressed or not based on the master cylinder pressure value detected by the brake controller 8, a threshold value of the master cylinder pressure of the brake device is stored in the vehicle control unit 9, and when the master cylinder pressure value is larger than the threshold value, the vehicle control unit 9 determines that the brake pedal 6 is depressed at this time.
When the vehicle control unit 9 detects that the brake pedal 6 is stepped on and determines that the driver has a braking behavior, the vehicle control unit controls the vehicle control unit 9 by referring to the opening and closing threshold of the electric vacuum pump 4 stored in the vehicle control unit 9 according to the selected first pressure value or the selected second pressure value as an ambient pressure value, and the specific control steps are as follows:
step S301, the whole vehicle control unit 9 receives vacuum degree data in the air chamber of the brake vacuum booster 1 detected by the vacuum degree sensor 2.
In the step, a vacuum degree sensor 2 arranged on an air chamber of the brake vacuum booster 1 detects the vacuum degree in the air chamber and transmits the vacuum degree to a whole vehicle control unit 9.
Step S302, the vehicle control unit 9 compares the vacuum degree data detected by the vacuum degree sensor 2 with the opening and closing threshold of the electric vacuum pump 4.
The vehicle control unit 9 stores therein the opening and closing thresholds of the electric vacuum pump 4 under the standard condition obtained from the test.
Step S303, when the vacuum degree data detected by the vacuum degree sensor 2 is smaller than the opening threshold of the electric vacuum pump 4, the whole vehicle control unit 9 controls the electric vacuum pump 4 to be opened, and when the vacuum degree data detected by the vacuum degree sensor 2 is larger than the closing threshold of the electric vacuum pump 4, the whole vehicle control unit 9 controls the electric vacuum pump 4 to be closed.
In this step, after comparing the vacuum signal obtained by the vacuum sensor 2 with the opening and closing threshold, it is obtained whether the electric vacuum pump 4 needs to be opened, and the vehicle control unit 9 outputs a control signal of the electric vacuum pump 4 according to the result to control the start and stop of the electric vacuum pump 4.
It should be understood that the above-described embodiments of the present invention are merely examples for clearly illustrating the present invention and are not intended to limit the embodiments of the present invention. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the claims of the present invention.
Claims (10)
1. The utility model provides an electric automobile vacuum servo system's ambient pressure detecting system which characterized in that includes:
the brake vacuum booster (1) is communicated with the brake device through a hydraulic pipeline;
a vacuum sensor (2) capable of measuring the vacuum of the air chamber of the brake vacuum booster (1);
a vacuum air storage tank (3) communicated with the air chamber;
the electric vacuum pump (4) is communicated with the vacuum air storage tank (3);
the check valve (5) is arranged on a communication pipeline of the electric vacuum pump (4) and the vacuum air storage tank (3);
a brake pedal (6) connected to a push rod of the brake vacuum booster (1);
a brake switch (7) capable of detecting whether the brake pedal (6) is depressed;
a brake controller (8) capable of measuring a master cylinder pressure value of the brake device;
the vehicle control unit (9), an ambient pressure sensor is arranged in the vehicle control unit (9), the vacuum sensor (2), the electric vacuum pump (4), the brake switch (7), the ambient pressure sensor and the brake controller (8) are respectively and electrically connected to the vehicle control unit (9), atmospheric pressure value data corresponding to the altitude are stored in the vehicle control unit (9), the atmospheric pressure value acquired by the ambient pressure sensor is a first pressure value, the atmospheric pressure value calculated by the vehicle control unit (9) through the altitude positioned by the positioning module is a second pressure value, the vehicle control unit (9) can periodically compare the first pressure value with the second pressure value, when the difference value between the first pressure value and the second pressure value is greater than a first limit value, the vehicle control unit (9) records a reliability error once, and in a set driving cycle, when the number of recorded reliability errors is greater than a second limit value, the vehicle control unit (9) judges that the ambient pressure sensor has a reliability fault;
when the reliability of the environmental pressure is detected to be wrong, a first pressure value acquired by the environmental pressure sensor is abandoned in the driving circulation, a second pressure value obtained through calculation is used for substitution, and when the reliability of the environmental pressure reported by the whole vehicle control unit (9) is wrong, the environmental pressure sensor can be prompted to be repaired.
2. The environmental pressure detection system of the vacuum boosting system of the electric vehicle according to claim 1, wherein the brake switch (7) comprises a main brake switch and an auxiliary brake switch, and the vehicle control unit (9) determines whether the brake pedal (6) is pressed according to the difference of the received switch signals of the main brake switch and the auxiliary brake switch.
3. The ambient pressure detection system of an electric vehicle vacuum assist system as claimed in claim 2, wherein the main brake switch is a normally open switch, and the auxiliary brake switch is a normally closed switch.
4. The environmental pressure detection system of the vacuum boosting system of the electric vehicle according to claim 1, wherein the vehicle control unit (9) can update the atmospheric pressure value data corresponding to the altitude in a networked manner.
5. An environmental pressure detection method of an electric vehicle vacuum boosting system, characterized in that the environmental pressure detection system of the electric vehicle vacuum boosting system according to any one of claims 1 to 4 is adopted, and comprises:
the whole vehicle control unit (9) acquires a first pressure value through an environmental pressure sensor;
the whole vehicle control unit (9) calculates a second pressure value through the altitude positioned by the positioning module;
the whole vehicle control unit (9) compares the first pressure value with the second pressure value, and when the difference value between the first pressure value and the second pressure value is larger than a limit value, a primary reliability error is recorded;
and in the set driving cycle, when the number of times of reliability errors recorded by the whole vehicle control unit (9) is greater than a limit value, judging that the reliability fault exists in the environment pressure sensor.
6. The environmental pressure detection method of the vacuum power assisting system of the electric automobile according to claim 5, wherein when the difference value between the first pressure value and the second pressure value is not greater than the limit value, the entire automobile control unit (9) controls the electric vacuum pump (4) to act by taking the first pressure value as the environmental pressure value.
7. The environmental pressure detection method of the vacuum power assisting system of the electric automobile according to claim 5, wherein when a difference value between the first pressure value and the second pressure value is larger than a limit value, the entire automobile control unit (9) controls the electric vacuum pump (4) to act by taking the second pressure value as the environmental pressure value.
8. The environmental pressure detection method of the vacuum power-assisted system of the electric vehicle as claimed in claim 5, wherein the brake switch (7) comprises a main brake switch and an auxiliary brake switch, and the vehicle control unit (9) determines that the brake pedal (6) is pressed when the switch signals of the main brake switch and the auxiliary brake switch are the same.
9. The environmental pressure detection method of the vacuum boosting system of the electric vehicle according to claim 8, wherein when the switch signals of the main brake switch and the auxiliary brake switch received by the vehicle control unit (9) are different, whether the brake pedal (6) is pressed down is determined by the master cylinder pressure value detected by the brake controller (8).
10. The environmental pressure detection method of the vacuum boosting system of the electric vehicle as claimed in claim 5, wherein the vehicle control unit (9) divides the difference between the first pressure value and the second pressure value by the second pressure value to obtain a deviation percentage, and records a reliability error when the deviation percentage exceeds a limit amount.
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| CN115214581B (en) * | 2022-05-18 | 2023-07-25 | 广州汽车集团股份有限公司 | Control method and device, vehicle and storage medium |
| FR3140126A1 (en) * | 2022-09-22 | 2024-03-29 | Psa Automobiles Sa | MONITORING THE NORMALITY OF DETERMINED ATMOSPHERIC PRESSURE IN A VEHICLE |
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