CN113530696B - Fuel system of automobile and leakage detection method of fuel system - Google Patents

Abstract

The application discloses a fuel system of an automobile and a leakage detection method of the fuel system, wherein the fuel system comprises a fuel vapor recovery tank and a leakage detection device; the leakage detection device comprises a microcontroller, a detector and a pressure regulator; an actuating mechanism of the pressure regulator is in signal connection with the microcontroller, and an air outlet of the pressure regulator is connected with the fuel vapor recovery tank; the detector comprises a first cavity and a second cavity, a first communication port is formed in an air outlet of the first cavity, a first valve core is arranged on the first communication port, and the first valve core is opened and closed through a locking mechanism; in the inflating and pressure maintaining stage, the locking mechanism is in a first state and controls the first valve core to be closed; and in the normal exhaust stage, the locking mechanism is in a second state and controls the first valve core to be opened. The method and the device for detecting the pressure drop of the reference hole fundamentally solve the problems of detection errors and false alarms caused by the reference hole by adopting a mode of measuring the pressure and judging the pressure drop.

Description

Fuel system of automobile and leakage detection method of fuel system

Technical Field

The application relates to the technical field of automobiles, in particular to a fuel system of an automobile and a leakage detection method of the fuel system.

Background

With the improvement of environmental awareness, emission regulations of traditional fuel vehicles in various countries are more and more strict, and the traditional fuel vehicles have an on-board diagnostic system (OBD) which becomes a mainstream trend. In the prior art, positive pressure or negative pressure is formed in a fuel system to judge whether a leakage point exists or not, so that OBD detection of the fuel system is completed.

At present, the main leakage detection mode is to determine a current change standard value of a motor or a pressure change standard value of a fuel system by using a reference hole arranged on a leakage detection module, and evaluate the leakage of the fuel system by taking the current change value or the pressure change standard value as a reference value.

Fig. 1 shows an embodiment of the prior art. As shown in fig. 1, the fuel tank is connected to a fuel vapor recovery tank, and a leak detection module having a reference hole is provided at an air outlet of the fuel vapor recovery tank. In the leakage detection process, the air circuit in the leakage detection module is switched to the detection air circuit through the electromagnetic valve, then the motor is started, air passes through the air filter and the air circuit where the reference hole is located, so that the local air circuit forms a positive pressure state or a negative pressure state, and the pressure change value of the local air circuit is monitored as a reference value within preset time. And then, the gas path is switched into air by the electromagnetic valve, and the air path is simultaneously filtered and detected, so that the fuel system forms a positive pressure state or a negative pressure state, the pressure change value of the fuel system is detected within preset time, the pressure value is compared with a reference value, and whether the fuel system leaks or not is judged, if the pressure value is lower than the reference pressure value, the fuel system does not leak, and if the pressure value is higher than the reference pressure value, the fuel system leaks.

However, the reference holes have the problems of production uniformity and fluctuation, and if errors exist in the production and manufacturing processes of the reference holes, the measurement results are directly inaccurate. In addition, due to the fact that the size of the reference hole is small, when dust blocks the reference hole, false alarm can be caused, and the product design and development process is complex and long in period.

Disclosure of Invention

The application provides a fuel system of an automobile and a leakage detection method of the fuel system, which fundamentally solve the problems of detection error and false alarm caused by a reference hole by adopting a mode of measuring pressure and judging pressure drop.

The application provides a fuel system of an automobile, wherein a pressure sensor is arranged on the fuel system, and the fuel system comprises a fuel vapor recovery tank and a leakage detection device;

the leakage detection device comprises a microcontroller, a detector and a pressure regulator;

the microcontroller is in signal connection with the pressure sensor;

an actuating mechanism of the pressure regulator is in signal connection with the microcontroller, and an air outlet of the pressure regulator is connected with the fuel vapor recovery tank;

the detector comprises a first cavity and a second cavity, wherein an air inlet of the first cavity is connected with an air outlet of the fuel steam recovery tank, an air outlet of the first cavity is communicated with the atmosphere through the second cavity, a first communication port is formed in the air outlet of the first cavity, a first valve core is arranged on the first communication port, and the first valve core is opened and closed through a locking mechanism;

in the inflating and pressure maintaining stage, the locking mechanism is in a first state and controls the first valve core to be closed;

and in the normal exhaust stage, the locking mechanism is in a second state and controls the first valve core to be opened.

Preferably, the detector further comprises a third cavity, the air inlet of the third cavity is connected with the air outlet of the pressure regulator, and the air outlet of the third cavity is connected with the fuel vapor recovery tank.

Preferably, the third cavity comprises a first sub cavity and a second sub cavity, the first sub cavity is provided with an air inlet of the third cavity, the second sub cavity is provided with an air outlet of the third cavity, a second communicating port is arranged between the second sub cavity and the first sub cavity, and the second communicating port is provided with a second valve core.

Preferably, the second valve cartridge is opened and closed by a micro-solenoid valve, which is in signal connection with the microcontroller.

Preferably, the second valve core is provided with a rebound mechanism on the side facing the second sub-cavity.

Preferably, the detector further comprises a fourth cavity, the fourth cavity being disposed between the second cavity and the first sub-cavity.

Preferably, a damping hole is arranged between the fourth cavity and the first sub-cavity or a vent hole is arranged between the fourth cavity and the second sub-cavity.

Preferably, a rubber diaphragm is arranged between the fourth cavity and the first sub-cavity;

locking mechanism's actuating mechanism includes the push rod, the first end and the rubber diaphragm fixed connection of push rod, and the push rod passes fourth cavity and second cavity and extends to first opening.

Preferably, a guide rail for the push rod to pass through is arranged on the side wall of the fourth cavity, which is close to the second cavity.

The application also provides a leakage detection method of the fuel system, based on the automobile fuel system, the leakage detection method comprises the following steps:

controlling the lock mechanism to switch from the second state to the first state such that the first valve element is closed in response to receiving the leak detection signal;

controlling the pressure regulator to pump air to the fuel system;

controlling an actuator of the pressure regulator to stop running in response to the pressure of the fuel system reaching a predetermined pressure, and enabling the fuel system to enter a pressure maintaining state;

collecting a pressure signal of a fuel system within a preset time;

calculating a difference value between the earliest pressure value and the latest pressure value within preset time to serve as a pressure change detection value;

judging whether the leakage detection is qualified or not according to the difference value between the pressure change detection value and the pressure change standard value, and judging that the leakage detection is qualified if the difference value between the pressure change detection value and the pressure change standard value is smaller than a threshold value;

and in response to the end of the leakage detection, controlling the locking mechanism to be switched from the first state to the second state, so that the first valve core is opened to release the pressure.

Further features of the present application and advantages thereof will become apparent from the following detailed description of exemplary embodiments thereof, which is to be read in connection with the accompanying drawings.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the application and together with the description, serve to explain the principles of the application.

FIG. 1 is a gas path diagram of leak detection in the prior art;

FIG. 2 is a schematic illustration of a fuel system of an automobile according to the present disclosure;

FIG. 3 is a state diagram of a detector in an embodiment provided herein during a normal exhaust phase;

FIG. 4 is a first state diagram of a detector during an inflation phase according to an embodiment of the present disclosure;

FIG. 5 is a second state diagram of the detector of one embodiment provided herein during a pump-up phase;

FIG. 6 is a state diagram of a detector in an embodiment provided herein during a dwell detection phase;

FIG. 7 is a first state diagram of a detector in an deflation phase according to an embodiment of the present application;

FIG. 8 is a second state diagram of the detector in a deflation phase according to one embodiment of the present application;

FIG. 9 is a block diagram of a detector in accordance with another embodiment of the present application during a normal exhaust phase;

FIG. 10 is a first state diagram of a detector in accordance with another embodiment of the present application during a pump-up phase and a pump-down phase;

FIG. 11 is a second state diagram of a detector during a pump-up phase according to another embodiment of the present application;

FIG. 12 is a state diagram of a detector in another embodiment provided herein during a dwell detection phase;

FIG. 13 is a second state diagram of the detector of another embodiment provided herein during a deflation phase;

FIG. 14 is a flow chart of a method of leak detection of a fuel system provided herein.

Detailed Description

Various exemplary embodiments of the present application will now be described in detail with reference to the accompanying drawings. It should be noted that: the relative arrangement of the components and steps, the numerical expressions, and numerical values set forth in these embodiments do not limit the scope of the present application unless specifically stated otherwise.

The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the application, its application, or uses.

Techniques, methods, and apparatus known to one of ordinary skill in the relevant art may not be discussed in detail, but are intended to be part of the specification where appropriate.

In all examples shown and discussed herein, any particular value should be construed as exemplary only and not as limiting. Thus, other examples of the exemplary embodiments may have different values.

The application provides a fuel system of an automobile, and as shown in figure 2, a pressure sensor 8 is arranged on the fuel system. The fuel system includes a fuel tank 1, a fuel vapor recovery tank 2, a leak detection device, and an air cleaner 4. The leak detection means comprises a microcontroller 7, a detector 3 and a pressure regulator. The microcontroller 7 is connected to a pressure sensor signal 8.

As shown in fig. 2, an outlet of the fuel tank 1 is connected to the fuel vapor recovery tank 2, and an outlet of the fuel vapor recovery tank 2 is connected to the detector 3 through a pipe 11. The outlet of the detector 3 is connected to the atmosphere 6 via a line 12 and an air filter 4.

As an example, as shown in fig. 2, the pressure sensor 8 is mounted on the fuel tank 1.

As an example, as shown in fig. 2, an isolation valve 5 is provided between the fuel tank 1 and the fuel vapor recovery tank 2.

The pressure regulator is used for charging the fuel system and is driven by an actuating mechanism, the actuating mechanism of the pressure regulator is in signal connection with the microcontroller 7, and the microcontroller 7 controls the action of the actuating mechanism. Referring to fig. 3, as an example, the pressure regulator is a pump 24 and the actuator is a motor 25.

Example one

Fig. 3-8 are block diagrams of a detector according to one embodiment provided herein. As shown in fig. 3, the detector includes a casing 18, an exhaust passage is provided in the casing 18, a first cavity 21 is provided on the exhaust passage, an air inlet of the first cavity 21 is connected to an air outlet of the fuel vapor recovery tank 2, and an air outlet of the first cavity 21 is communicated with the air cleaner 4 through a second cavity 22, and further communicated with the atmosphere. The gas outlet of the first cavity 21 is provided with a first communication port 29, the first communication port 29 is provided with a first valve core 31, the first valve core 31 is opened and closed through a locking mechanism 35, normal exhaust of the fuel system and gas leakage after leakage detection are achieved when the first valve core 31 is opened, and the first valve core is used for inflating and maintaining pressure of the fuel system when the first valve core is closed.

Specifically, in the pump-up phase, the lock mechanism 35 is in the first state, and the lock mechanism 35 controls the first valve spool 31 to close. In the normal exhaust stage or the deflation stage after the leak detection is completed, the locking mechanism 35 is in the second state, and the locking mechanism 35 controls the first valve core 31 to be opened.

As an example, the principle of the locking mechanism 35 is the same as that of the push switch. Referring to fig. 3, in fig. 3, the locking mechanism 35 is in a self-locking state (i.e., a second state), and the first valve element is opened. When the lock mechanism 35 is operated (e.g., pushed or compressed), it enters an unlocked state (i.e., a first state) from the self-locking state, the first valve spool 31 is pushed to the first communication port 29, and the first valve spool 31 is closed. If the lock mechanism 35 is operated again, the lock mechanism 35 enters the self-lock state from the unlock state, and the first valve spool 31 is opened.

The prior art discloses various button switches, such as a push switch of a push type sign pen, a power switch on a patch board, and the like.

As shown in FIG. 3, a third cavity is further provided in the housing 18 of the detector, an air inlet of the third cavity is connected with an air outlet of the pressure regulator 24, and an air outlet of the third cavity is connected with an air outlet of the fuel vapor recovery tank 2. The third cavity is arranged between the pressure regulator 24 and the fuel steam recovery tank 2, so that the pumping rhythm can be controlled more conveniently in the pumping stage, and the pumping channel and the exhaust channel are integrated by the detector, so that the integration level of the fuel system is improved.

Preferably, as shown in fig. 3, the air inlet of the pressure regulator 24 is connected with the air inlet of the air filter 4, so that the overall structure of the detector is compact, and the space utilization rate of the fuel system is improved.

It should be noted that, in the embodiment without a partition sub-cavity in the third cavity, the pump 24 has a pressure maintaining function, so that the pressure of the fuel system is maintained in the leak detection stage.

As shown in fig. 3, preferably, the third cavity includes a first sub-cavity 19 and a second sub-cavity 20, an air inlet of the third cavity is provided on the first sub-cavity 19, an air outlet of the third cavity is provided on the second sub-cavity 20, a second communicating opening 28 is provided between the second sub-cavity 20 and the first sub-cavity 19, and a second valve core 30 is provided on the second communicating opening 28. In the embodiment shown in fig. 3, the second valve spool 30 is opened and closed by a micro-solenoid valve 27, and the micro-solenoid valve 27 is in signal connection with the microcontroller 7, and the micro-solenoid valve 27 is controlled by the microcontroller 7.

On the basis of the above preferred embodiment, as shown in fig. 3, the detector further includes a fourth cavity 23, the fourth cavity 23 is disposed between the second cavity 22 and the first sub-cavity 19, and a vent 32 is disposed between the fourth cavity 23 and the second sub-cavity 20.

As shown in fig. 3, a rubber diaphragm 26 is provided between the fourth cavity 23 and the first sub-cavity 19. The detector further comprises a driving mechanism of a locking mechanism 35, the driving mechanism comprises a push rod 33, a first end of the push rod 33 is fixedly connected with the rubber diaphragm 26, and the push rod 33 penetrates through the fourth cavity 23 and the second cavity 22 and extends towards the first communication opening 29. In such a mechanism, the pump 24 has both an air pumping function and a pressure relief function.

Preferably, a guide rail 34 for the push rod 33 to pass through is provided on the side wall of the fourth cavity 23 close to the second cavity 22, so as to provide a guide for the push rod 33. On this basis, preferably, a sealing ring is provided between the push rod 33 and the guide rail 34.

Preferably, the first cavity 21 and the second cavity 22 share a side wall, and the second cavity 22 and the fourth cavity 23 share a side wall, so that the detector has a simple and compact structure, and the space utilization rate of the detector is improved.

In this embodiment, FIG. 3 shows the exhaust conditions during normal operation of the fuel system. The locking mechanism 35 is in a self-locking state, the first valve core 31 is opened, and gas enters the fuel vapor recovery tank 2 from the fuel tank 1, enters the second cavity 22 through the first cavity 21 and the first communication port 29, and is exhausted to the atmosphere through the air filter 4.

In response to receiving the leak detection signal, the fuel system enters a pump-up phase. Specifically, the microcontroller 7 controls the motor 25 to drive the pump 24 to rotate, so that the pressure in the first sub-cavity 19 rises, the rubber diaphragm 26 is pushed to move upwards, the push rod 33 and the first valve core 31 are pushed to move upwards, and the locking mechanism 35 is pushed, as shown in fig. 4. After a certain time delay, on the basis that the motor 25 and the pump 24 continue to work, the microcontroller 7 controls the micro electromagnetic valve 27 to be powered on, the second valve spool 30 is opened, gas enters the second sub-cavity 20 through the second communication port 28 and enters the fourth cavity 23 through the vent hole 32, so that the pressure in the first sub-cavity 19 and the pressure in the fourth cavity gradually tend to be equal, the pressure is finally balanced, the rubber diaphragm 26 is restored to the original state, and the push rod 33 moves downwards and returns to the original position. When the push rod 33 is disengaged from the first valve core 31, the locking mechanism 35 releases the self-locking state, and the first valve core 31 is pushed to the first communication port 29 by the locking mechanism 35, so that the first valve core is closed. At the same time, the gas enters the fuel tank 1 through the fuel vapor recovery canister 2 to inflate the fuel system, as shown in fig. 5.

The microcontroller 7 controls the motor 25 and the pump 24 to continue to work, and in response to the pressure sensor 8 detecting that the pressure of the fuel system reaches the preset pressure, the microcontroller 7 controls the motor 25 to stop and controls the micro-solenoid valve 27 to close the second valve spool 30, and the fuel system enters a pressure maintaining detection stage, as shown in fig. 6.

In response to the completion of the leak detection, the microcontroller 7 controls the motor 25 to drive the pump 24 to rotate, so that the pressure in the first sub-cavity 19 rises, the rubber diaphragm 26 is pushed to move upwards, the push rod 33 and the first valve core 31 are pushed to move upwards, and the locking mechanism 35 is pushed to move upwards, as shown in fig. 7. After a certain time is delayed, the microcontroller 7 controls the motor 25 to lose power, the gas in the first sub-cavity 19 is discharged to the atmosphere through the pump 24, the pressure of the fourth cavity 23, the fuel system and the first cavity 21 is relieved through the first communication port 29, the second cavity 22 and the air filter 4, finally the pressure in the first sub-cavity 19 is equal to the pressure in the fourth cavity 23, the rubber diaphragm 26 is restored, and the push rod 33 moves downwards and returns to the original position. When the push rod 33 is disengaged from the first valve core 31, the locking mechanism 35 enters a self-locking state, and a certain distance is reserved between the first valve core 31 and the first communication port 29, so that the first valve core 31 is opened. And (5) finishing the detection of the leakage property, and enabling the fuel system to enter a normal exhaust state.

Example two

In view of the fact that a micro-solenoid valve increases the cost of the overall fuel system and the complexity of the control program, the present application provides another embodiment of the detector based on the above embodiment. Fig. 9-13 are block diagrams of detectors of another embodiment provided herein. This embodiment differs from the above embodiment in that: the driving mechanism of the first and second valve cores 30 is different, in this embodiment, a rebound mechanism 37 is provided on the side of the second valve core 30 facing the second sub-cavity, the second valve core 30 is opened by the pressure difference between the first sub-cavity 19 and the second sub-cavity 20, and the second valve core 30 is closed by the rebound mechanism 37. Cost is reduced by replacing the micro solenoid valve 27 with the rebound mechanism 37. Second, the vent 32 in the above embodiment is eliminated and the damping orifice 36 is provided between the fourth chamber 22 and the first sub-chamber 19.

It should be noted that, the embodiment that the second valve core is opened by the aforementioned rebound mechanism and the rubber diaphragm is restored by the aforementioned vent hole, and the embodiment that the second valve core is opened by the aforementioned micro-electromagnetic valve and the rubber diaphragm is restored by the aforementioned damper hole are both solutions that can achieve the same function under the inventive concept of the present application.

As one example, as shown in fig. 9-13, the resilient mechanism 37 is a spring.

In the embodiment shown in fig. 9-13, fig. 9 is a normal venting condition of the fuel system, in which the pump 24 is not operating, the second spool 30 is closed by the resilient mechanism, the pressures in the first subchamber 19 and the fourth chamber 23 are both atmospheric, and the rubber diaphragm 26 and the pushrod 33 remain in place. The locking mechanism 35 is in a self-locking state, the first valve core 31 is opened, and gas in the fuel tank 1 enters the atmosphere 6 through the fuel vapor recovery tank 2, the air inlet of the first cavity 21, the first communication port 29, the second cavity 22, the air outlet of the detector and the air filter 4.

In response to receiving the leak detection signal, the fuel system enters a pump-up phase. Specifically, the microcontroller 7 controls the motor 25 to drive the pump 24 to rotate, so that the pressure in the first sub-cavity 19 rises, the pressure in the fourth cavity 23 rises after being delayed due to the action of the damping hole 36, and in the process, the rubber diaphragm 26 moves upwards and pushes the push rod 33 and the first valve core 31 to move upwards, so that the locking mechanism 35 is pushed, at this time, the first communication port 29 is kept open, and the second valve core 30 is kept closed under the action of the rebound mechanism, as shown in fig. 10. The motor 25 and the pump 24 continue to work, the pressure in the first sub-cavity 19 and the pressure in the fourth cavity 23 are consistent after a certain time, the rubber diaphragm 26 and the push rod 33 recover downwards, the locking mechanism 35 is changed from a self-locking state to an unlocking state, the first valve core 31 is pushed to move to the first communication port 29, and the first valve core 31 is closed. The pressure in the first sub-chamber 19 continues to rise and when the pressure difference between the first sub-chamber 19 and the second sub-chamber 20 is greater than the spring force of the resilient mechanism 37, the second spool 30 opens and the pump 24 continues to pump gas into the fuel system, as shown in fig. 11.

In response to the pressure sensor 8 detecting that the pressure in the fuel system reaches the preset pressure, the microcontroller 7 controls the motor 25 to stop, and since the pump 24 has a pressure relief effect, the pressure in the first sub-chamber 19 is rapidly restored to the atmospheric pressure, so that the pressure in the first sub-chamber 19 is smaller than the sum of the pressure in the second sub-chamber 20 and the elastic force of the rebound mechanism 37, the second valve spool 30 is closed, and the fuel system enters a pressure maintaining detection stage, as shown in fig. 12.

In response to completion of the leak detection, the fuel system enters a bleed phase. Specifically, the microcontroller 7 controls the motor 25 to drive the pump 24 to rotate, the pressure in the first sub-cavity 19 rises, the pressure in the fourth cavity 23 rises after being delayed due to the action of the damping hole 36, the rubber diaphragm 26 moves upwards in the process, and the push rod 33 and the first valve core 31 are pushed to move upwards, so that the locking mechanism 35 is pushed. At this time, the first valve spool 31 is opened, and the second valve spool 30 is kept closed by the rebound mechanism, see fig. 10. After a certain time delay, the pressures in the first sub-cavity 19 and the fourth cavity 23 are equal, the rubber diaphragm 26 and the push rod 33 are restored downwards, the locking mechanism 35 is changed from the unlocking state to the self-locking state, so that the first valve core 31 is kept open, the second valve core 30 is always kept closed under the action of the rebounding mechanism, the microcontroller 7 controls the motor 25 to lose power, and the fuel system enters a normal exhaust state, as shown in fig. 13.

EXAMPLE III

The application also provides a leakage detection method matched with the fuel system. As shown in fig. 14, the leak detection method includes the steps of:

s1410: in response to receiving the leak detection signal, the lock mechanism is controlled to shift from the second state to the first state such that the first spool is closed.

S1420: and controlling the pressure regulator to pump air to the fuel system.

S1430: the actuator controlling the pressure regulator is deactivated in response to the pressure in the fuel system reaching a predetermined pressure, and the fuel system enters a pressure maintaining state.

S1440: and acquiring a pressure signal of the fuel system within a preset time.

S1450: and calculating the difference value between the earliest pressure value and the latest pressure value in the preset time as the pressure change detection value.

And then, judging whether the leakage detection is qualified or not according to the difference value of the pressure change detection value and the pressure change standard value. Specifically, steps S1460-S1480 are included

S1460: and judging whether the difference value between the pressure change detection value and the pressure change standard value is smaller than a threshold value. If so, then S1470 is performed, otherwise, S1480 is performed.

S1470: and judging that the leakage detection is qualified.

S1480: and judging that the leakage detection is unqualified.

S1490: after steps S1470 and S1480, in response to the end of the leak detection, the lock mechanism is controlled to shift from the first state to the second state so that the first valve element is opened to release the pressure.

In step S1410 and step S1490, the driving mechanism for driving the lock mechanism by the pressure regulator pushes the lock mechanism to switch the state.

The beneficial effect of this application is as follows:

1. the method and the device for detecting the pressure drop of the gas turbine eliminate the reference hole, and fundamentally solve the problems of detection errors and false alarms caused by the reference hole by adopting a mode of measuring the pressure and judging the pressure drop.

2. This application adopts the inside case of detector to realize that pressurization, pressurize of fuel oil system detect and the pressure release, and simple structure has reduced manufacturing cost.

3. This application adopts the locking mechanism who has self-locking mechanism, realizes the quick switching of case, simple structure to low in production cost.

4. Adjacent cavity sharing lateral wall in this application for simple structure is compact, has improved detector and fuel oil system's space utilization.

Although some specific embodiments of the present application have been described in detail by way of example, it should be understood by those skilled in the art that the above examples are for illustrative purposes only and are not intended to limit the scope of the present application. It will be appreciated by those skilled in the art that modifications may be made to the above embodiments without departing from the scope and spirit of the present application. The scope of the application is defined by the appended claims.

Claims (10)

1. The automobile fuel system is characterized in that a pressure sensor is arranged on the fuel system, and the fuel system comprises a fuel vapor recovery tank and a leakage detection device;

the leak detection device comprises a microcontroller, a detector and a pressure regulator;

the microcontroller is in signal connection with the pressure sensor;

an actuating mechanism of the pressure regulator is in signal connection with the microcontroller, and an air outlet of the pressure regulator is connected with the fuel vapor recovery tank;

the detector comprises a first cavity and a second cavity, wherein an air inlet of the first cavity is connected with an air outlet of the fuel vapor recovery tank, an air outlet of the first cavity is communicated with the atmosphere through the second cavity, a first communication port is formed in the air outlet of the first cavity, a first valve core is arranged on the first communication port, and the first valve core is opened and closed through a locking mechanism;

in the inflating and pressure maintaining stage, the locking mechanism is in a first state and controls the first valve core to be closed;

in the normal exhaust stage, the locking mechanism is in a second state and controls the first valve core to be opened.

2. The automotive fuel system of claim 1, wherein the detector further comprises a third chamber, an air inlet of the third chamber is connected to an air outlet of the pressure regulator, and an air outlet of the third chamber is connected to the fuel vapor recovery canister.

3. The automobile fuel system according to claim 2, wherein the third cavity includes a first sub-cavity and a second sub-cavity, an air inlet of the third cavity is provided on the first sub-cavity, an air outlet of the third cavity is provided on the second sub-cavity, a second communicating opening is provided between the second sub-cavity and the first sub-cavity, and a second valve core is provided on the second communicating opening.

4. The fuel system of an automobile according to claim 3, wherein the second spool is opened and closed by a micro-solenoid valve, which is in signal connection with the microcontroller.

5. The automotive fuel system of claim 3, wherein a rebound mechanism is provided on a side of the second spool facing the second sub-chamber.

6. The fuel system of an automobile according to claim 4 or 5, wherein the detector further comprises a fourth cavity disposed between the second cavity and the first sub-cavity.

7. The automobile fuel system as claimed in claim 6, wherein a damping hole is provided between the fourth cavity and the first sub-cavity or a vent hole is provided between the fourth cavity and the second sub-cavity.

8. The automotive fuel system of claim 7, wherein a rubber diaphragm is disposed between the fourth cavity and the first sub-cavity;

the driving mechanism of the locking mechanism comprises a push rod, the first end of the push rod is fixedly connected with the rubber diaphragm, and the push rod penetrates through the fourth cavity and the second cavity and extends to the first communication port.

9. The automobile fuel system as claimed in claim 8, wherein a guide rail for a push rod to pass through is provided on a side wall of the fourth cavity close to the second cavity.

10. A method of detecting a leak in a fuel system of an automobile according to any one of claims 1 to 9, the method comprising:

controlling the lock mechanism to switch from the second state to the first state such that the first valve spool is closed in response to receiving a leak detection signal;

controlling the pressure regulator to pump air to the fuel system;

controlling an actuator of the pressure regulator to stop operating in response to a pressure of a fuel system reaching a predetermined pressure, the fuel system entering a pressure holding state;

collecting a pressure signal of the fuel system within a preset time;

calculating the difference value between the earliest pressure value and the latest pressure value in the preset time to be used as a pressure change detection value;

judging whether the leakage detection is qualified or not according to the difference value between the pressure change detection value and the pressure change standard value, and if the difference value between the pressure change detection value and the pressure change standard value is smaller than a threshold value, judging that the leakage detection is qualified;

and in response to the end of the leakage detection, controlling the locking mechanism to be switched from the first state to the second state, so that the first valve core is opened to release the pressure.

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