KR101713723B1 - Detection system of deterioration of a fuel pressure sensor and detection method - Google Patents

Abstract

A common rail for storing the compressed fuel and maintaining the pressure of the fuel, a high-pressure pump for compressing the fuel to supply the compressed fuel to the common rail, a fuel pressure sensor for measuring the pressure of the fuel in the common rail, A pressure limiting valve which is opened when the pressure of the fuel reaches a first pressure and decreases when the pressure reaches a second pressure which is higher than the first pressure, A deterioration detection system of a fuel pressure sensor is disclosed that includes a control unit that detects deterioration of a fuel pressure sensor.

Description

TECHNICAL FIELD [0001] The present invention relates to a deterioration detection system for a fuel pressure sensor and a method for detecting the deterioration of the fuel pressure sensor,

The present invention relates to a deterioration detection system for a fuel pressure sensor and a method of sensing the deterioration of the fuel pressure sensor, and more particularly, to a deterioration detection system and method for detecting deterioration of a fuel pressure sensor utilizing a fuel pressure sensor deterioration detection system and a pressure- ≪ / RTI >

The common rail system stores the high-pressure fuel in the common rail, maintains the pressure constant, supplies the fuel to the injector using the high pressure of the fuel, and appropriately controls the injection amount of the fuel in the injector. Generally, the fuel injection amount is controlled by using a fuel pressure sensor mounted on a common rail.

When the fuel pressure sensor is deteriorated during operation of the vehicle, the deteriorated fuel pressure sensor may adversely affect the engine output and exhaust gas control, since the actual fuel injection amount is different from the fuel injection amount set by the control logic .

FIGS. 1 and 2 are graphs showing changes in the actual fuel injection amount due to deterioration of the fuel pressure sensor.

1 and 2, the pressure axis represents the pressure in the common rail, and the voltage axis represents the voltage that the fuel pressure sensor outputs in response to the pressure in the common rail. Also, the bold line is the characteristic line of the normal fuel pressure sensor set by the control logic, and the thin line is the characteristic line of the deteriorated actual fuel pressure sensor.

Referring to Figures 1 and 2, for the same output voltage, region 1 is the region where the actual common rail pressure is lower than the normal pressure stored in the control logic, region 2 is the actual common rail pressure Is higher than the normal pressure stored in the control logic.

Therefore, in the region 1, the fuel injection quantity is lower than the preset amount in the control logic because the actual common rail pressure is lower, and in the region 2, the actual common rail pressure is higher, .

The generation pattern of the region 1 and the region 2 varies depending on the deterioration pattern of the fuel pressure sensor, but in all cases, the control of the fuel injection amount is not performed as designed. As a result, the control of the engine output and the control of the exhaust gas amount can not be performed as intended.

SUMMARY OF THE INVENTION An object of the present invention is to provide a system for detecting deterioration of a fuel pressure sensor without increasing a cost and a method of sensing the deterioration of the fuel pressure sensor.

In one or more embodiments of the present invention there is provided a fuel injection system including a common rail for storing compressed fuel and maintaining the pressure of the fuel, a high pressure pump for compressing the fuel to supply the compressed fuel to the common rail, A fuel pressure sensor for measuring a pressure, a pressure limiting valve which reduces a pressure by a certain amount when the pressure of the fuel in the common rail reaches a first pressure, and opens when a second pressure which is higher than the first pressure is reached, And a controller for receiving the measurement signals of the sensor and sensing deterioration of the fuel pressure sensor.

The pressure limiting valve may include a first check valve and a second check valve, and the first check valve and the second check valve may be connected in series in order.

The first check valve may include a first spring, a first valve cap, and a first chamber, and the second check valve may include a second spring, a second valve cap, and a second chamber.

The first spring constant of the first spring and the second spring constant of the second spring may be set such that the first check valve and the second check valve are opened at the first pressure and the second pressure, respectively .

The method of sensing a deterioration sensing system of a fuel pressure sensor according to an embodiment of the present invention may include the steps of determining by the control unit whether a difference between two measured pressures corresponding to two measurement times exceeds a first set value, And determining, by the control unit, whether the larger one of the two measured pressures is within a predetermined first allowable range, when the difference exceeds the first set value.

The first permissible range may be set as a minimum value and a maximum value.

The sensing method may further include the step of determining, by the control unit, whether the measured pressure corresponding to an arbitrary measurement time is between a preset first minimum value and a first maximum value.

The sensing method may output a deterioration warning signal of the fuel pressure sensor by the control unit when a larger one of the two measured pressures is not within the first allowable range.

The sensing method may continue to monitor the pressure in the common rail by the controller if a higher pressure of the two measured pressures is within the first tolerance range.

Wherein the sensing method comprises the steps of: determining by the control unit whether a difference between two measured pressures corresponding to two measurement times exceeds a second set value; and if the difference exceeds the second set value, And determining whether a higher pressure of the two measured pressures is within a second predetermined allowable range.

The second permissible range may be set as a minimum value and a maximum value.

The sensing method may further include the step of determining, by the control unit, whether the measured pressure corresponding to a certain measurement time is between a preset second minimum value and a second maximum value.

The sensing method may output a deterioration warning signal of the fuel pressure sensor by the control unit when a larger one of the two measured pressures is not within the second allowable range.

The sensing method may terminate the deterioration detection of the fuel pressure sensor by the control unit when a larger one of the two measured pressures is within the second allowable range.

As described above, according to the present invention, deterioration of the fuel pressure sensor can be easily detected without burdening the cost, so that unexpected change in vehicle performance can be prevented and optimal vehicle performance can be maintained.

FIGS. 1 and 2 are graphs showing changes in the actual fuel injection amount due to deterioration of the fuel pressure sensor.
3 is a diagram of a common rail system according to an embodiment of the present invention.
4 is a cross-sectional view of a pressure limiting valve according to an embodiment of the present invention.
5 is a graph showing an example of a pressure change with time in a fuel pressure sensor deterioration detection system according to an embodiment of the present invention.
6 is a sectional view showing a state in which the pressure limiting valve is closed (mode 1) according to the embodiment of the present invention.
7 is a cross-sectional view showing a state in which the pressure limiting valve is partially opened (mode 2) according to the embodiment of the present invention.
8 is a cross-sectional view showing a state in which the pressure limiting valve is opened (mode 3) according to the embodiment of the present invention.
9 is a graph showing the principle of deterioration detection of the fuel pressure sensor.
10 is a graph showing an example of a pressure change with time in a fuel pressure sensor deterioration detection system according to an embodiment of the present invention.
11 is a schematic block diagram of a fuel pressure sensor deterioration detection system according to an embodiment of the present invention.
12 is a flowchart of a fuel pressure sensor deterioration detection method according to an embodiment of the present invention.
13 is a graph showing a first allowable range of two measured pressures corresponding to two measurement times and a pressure at a first pressure arrival point.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

 It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to be illustrative of the invention, and are not intended to limit the scope of the inventions. I will do it.

Throughout the specification, when an element is referred to as " comprising ", it means that it can include other elements as well, without excluding other elements unless specifically stated otherwise. Also, the name of a component does not limit the functionality of that component.

3 is a diagram of a deterioration monitoring system for a fuel pressure sensor according to an embodiment of the present invention.

The deterioration detection system of the fuel pressure sensor according to the embodiment of the present invention may have the same configuration as the common rail system.

Referring to FIG. 3, the deterioration detection system of the fuel pressure sensor according to the embodiment of the present invention includes a common rail 10 for storing compressed fuel and maintaining the pressure of fuel, A fuel pressure sensor 30 for measuring the pressure of the fuel in the common rail 10, a pressure sensor for detecting a pressure of the fuel in the common rail 10 when the pressure of the fuel in the common rail 10 reaches a first pressure A pressure limiting valve (40) that opens when the pressure reaches a second pressure greater than the first pressure, and a fuel pressure sensor (30) that receives measurement signals of the fuel pressure sensor And a control unit 50 for detecting the operation of the apparatus.

Therefore, the deterioration detection system of the fuel pressure sensor according to the embodiment of the present invention may have a configuration in which only the injector 60 is excluded in the common rail system of FIG. Of course, the system may include the injector 60.

The pressure limiting valve 40 may serve to limit the pressure in the common rail 10 to a maximum permissible pressure or less. Therefore, the second pressure can be the maximum allowable pressure. When the pressure limiting valve 40 is opened, the fuel flowing out from the common rail 10 returns to the fuel tank along the pipeline.

Due to the pressure limiting valve 40, the common rail 10 experiences two pressure changes until the maximum allowable pressure is reached. The pressure in the common rail 10 is reduced by a certain amount when the first pressure is reached in the low pressure range and is decreased in the high pressure range when the maximum allowable pressure (for example, the second pressure) It is reduced by opening. However, the pressure in the common rail 10 is not reduced without limitation, and the pressure can be maintained by the controller 50 after a certain amount of decrease.

When the pressure in the common rail 10 reaches the first pressure or the second pressure, the reason why the pressure in the common rail 10 is reduced by the pressure limiting valve 40 by a certain amount and the mechanism is described in detail below .

The controller 50 may be an electronic control unit (ECU).

4 is a cross-sectional view of a pressure limiting valve according to an embodiment of the present invention.

4, the pressure limiting valve 40 may include a first check valve 41 and a second check valve 42, and the first check valve 41 and the second check valve 42 (42) may be connected in series in series.

The first check valve 41 may include a first spring 41a, a first valve cap 41b and a first chamber 41c. The second check valve 42 may include a second valve 41b, A spring 42a, a second valve cap 42b, and a second chamber 42c.

In this case, the first spring constant of the first spring 41a and the second spring constant of the first spring 41a are set such that the first check valve 41 and the second check valve 42 are opened at the first pressure and the second pressure, The second spring constant of the spring 42a can be set differently. That is, the first spring constant may have a relatively low value so that the first check valve 41 is opened in a low pressure region, and the second spring constant may be relatively Can have a high value. Therefore, the maximum allowable pressure is determined by the second spring constant, and the first pressure is determined by the first spring constant.

Further, the amount of pressure immediately reduced when the pressure in the common rail 10 reaches the first pressure in the low-pressure region is determined by the volume of the first chamber 41c. Also, the amount of pressure immediately reduced when the pressure in the common rail 10 reaches the second pressure in the high-pressure region is determined by the volume of the second chamber 42c. The pressure can be kept constant by the control unit 50 after the instantaneous decrease.

5 is a graph showing an example of a pressure change with time in a fuel pressure sensor deterioration detection system according to an embodiment of the present invention.

In Fig. 5, pressure 1 represents the first pressure and pressure 2 represents the second pressure, i.e., the maximum permissible pressure. A practical use period of the pressure in the common rail 10 is shown. It is preferable for the fuel injection amount control to be controlled such that the pressure in the common rail 10 is kept between a value slightly larger than the first pressure and slightly smaller than the second pressure.

6 is a sectional view showing a state in which the pressure limiting valve is closed (mode 1) according to the embodiment of the present invention.

Referring to FIGS. 5 and 6, Mode 1 is a case where both the first and second check valves 41 and 42 of the pressure limiting valve 40 are closed at the initial stage of startup. In mode 1, the common rail 10 is filled with fuel in a state where the first check valve 41 is closed until the pressure in the common rail 10 exceeds the force of the first spring 41a. That is, the mode 1 corresponds to the starting section of FIG.

7 is a cross-sectional view showing a state in which the pressure limiting valve is partially opened (mode 2) according to the embodiment of the present invention.

5 and 7, in mode 2, the first check valve 41 is opened by filling the common rail 10 with fuel equal to or higher than the first pressure, but the pressure in the common rail 10 is lower than the pressure in the second check valve The second check valve 42 is closed because the pressure is not enough to overcome the force of the second spring 42a of the second check valve 42. However, when the first pressure is reached, the pressure in the common rail 10 is reduced by a certain amount as soon as the fuel flows into the first chamber 41c. That is, the mode 2 corresponds to a part of the starting section and the driving section of FIG.

8 is a cross-sectional view showing a state in which the pressure limiting valve is opened (mode 3) according to the embodiment of the present invention.

5 and 8, the mode 3 is a case in which the second check valve 42 is opened by filling the common rail 10 with fuel equal to or higher than the second pressure, whereby the pressure restriction valve 40 is opened . At this time, as the fuel flows into the second chamber 42c, the pressure in the common rail 10 instantaneously decreases by a certain amount. Thereafter, the pressure in the common rail 10 can be maintained at a constant pressure by the control unit 50. [ That is, the mode 3 corresponds to the state after the operation period of FIG.

9 is a graph showing the principle of deterioration detection of the fuel pressure sensor.

10 is a graph showing an example of a pressure change with time in a fuel pressure sensor deterioration detection system according to an embodiment of the present invention.

The deterioration detection of the fuel pressure sensor according to the embodiment of the present invention may be performed by the control unit 50 in at least one of the vehicle stop state and the running state. When the deterioration detection is performed while the vehicle is at rest, the deterioration detection system of the fuel pressure sensor 30 is controlled by the control unit 50 so that the mode 1, mode 2 And mode 3 in that order. Or in otherwise specified order.

When the deterioration detection is performed in the running state, the deterioration detection system of the fuel pressure sensor 30 may experience Mode 1, Mode 2, and Mode 3 according to the driving condition, in a predetermined order.

The method of detecting deterioration of the fuel pressure sensor 30 according to the embodiment of the present invention utilizes the characteristic that the pressure immediately decreases at the first pressure and the second pressure. That is, when the pressure reduction is measured by the fuel pressure sensor 30, the method determines that the pressure in the common rail 10 has reached the first pressure or the second pressure, do. The method further includes measuring the pressure at the first pressure arrival point in the low pressure region and the pressure at the second pressure arrival point in the high pressure region with the fuel pressure sensor 30 to determine whether the two measured values are within the permissible ranges, The control unit 50 judges whether or not there is an error.

The reason why the two values measured in the low-pressure region and the high-pressure region are used is that, as shown in Fig. 9, when the measurement is performed in only one of the low-pressure region and the high-pressure region, , But the opposite result may occur in the other.

Referring to FIG. 9, the characteristic line of deterioration 1 shows a normal measured value in the low pressure region but not in the high pressure region, and the characteristic line of the deterioration 2 shows a normal measured value in the high pressure region but not in the low pressure region.

Fig. 10 shows a case in which the measured values of the first pressure and the second pressure are within respective allowable ranges. In this case, the deterioration detection system of the fuel pressure sensor according to the embodiment of the present invention determines that the fuel pressure sensor 30 is normal, and, as shown in FIG. 9, Is more accurate than.

11 is a schematic block diagram of a fuel pressure sensor deterioration detection system according to an embodiment of the present invention.

11, a fuel pressure sensor deterioration detection system according to an embodiment of the present invention includes a fuel pressure sensor 30 for measuring a pressure of fuel in a common rail, and a fuel pressure sensor 30 for receiving measurement signals from the fuel pressure sensor 30 And a controller (50) for diagnosing and detecting deterioration of the fuel pressure sensor (30).

As described above, when the pressure of the fuel in the common rail 10 reaches the first pressure, the pressure in the common rail 10 of the detection system is decreased by a certain amount, and the pressure in the common rail 10 is decreased to the second pressure The pressure limiting valve 40 shown in Fig. The pressure restricting valve 40 may include a first check valve 41 and a second check valve 42 which are connected in series in series.

12 is a flowchart of a fuel pressure sensor deterioration detection method according to an embodiment of the present invention.

13 is a graph showing a first allowable range of two measured pressures corresponding to two measurement times and a pressure at a first pressure arrival point.

When 12 and 13, detection of the fuel pressure sensor deterioration detection system according to an embodiment of the present invention, corresponding by the controller 50, the two measurement times (t _i, t _{i + 1)} both the measured pressure _{(P (t i), P} (t i + 1)) determining whether the difference exceeds a first predetermined value (S20), and that if the difference is greater than the first predetermined value, (S30) of determining whether the larger _{one of} the two measured pressures (P (t _i ), P (t _{i + 1} )) is within a predetermined first permissible range by the control unit These are the steps for sensing the first pressure located in the low pressure region.

The embodiment of Fig. 12 shows the case of detecting the deterioration of the fuel pressure sensor 30 in the vehicle stop state. Accordingly, the high pressure pump 20 is operated (S10) to fill the common rail 10 with fuel, and the above steps are performed. In this case, mode 1, mode 2, and mode 3 may be performed in the predetermined order as shown in FIGS. 6, 7, and 8.

The larger _{one of} the two measured pressures P (t _i ) and P (t _{i +1} ) means P (t _i ), and P (t _i ) Lt; / RTI > Thus, the difference between the fuel pressure of the pressure values _{(P (t i), P} (t i + 1)) corresponding to the two measured time have or continuously pre-set time interval (t _i, t _{i + 1)} sensor The control unit 50 can determine that the pressure in the common rail 10 has reached the first pressure when the pressure P (t _i ) is greater than the error range of the output signal of the first pressure sensor 30, As shown in FIG. Therefore, the first set value may be an arbitrary value exceeding the error range of the output signal of the fuel pressure sensor 30. This is because, when the pressure is reduced within the error range of the output signal, the pressure in the common rail can not be determined to have reached the first pressure. That is, in order to distinguish between the fluctuation of the fuel pressure occurring when the fuel is pumped and the pressure fluctuation when the first check valve 41 is opened, the first set value is larger than the pressure fluctuation value when the fuel is pumped, 41c may be less than the pressure drop value generated when the fuel flows out.

13, when the control unit 50 determines that the pressure in the common rail 10 has reached the first pressure P (t _i ) is within the first allowable range, the fuel pressure sensor 30 Can be judged to be normal. On the other hand, if P (t _i ) is outside the first permissible range, the fuel pressure sensor 30 can be judged as deteriorated.

Referring to FIG. 12, the first allowable range may be set as a minimum value and a maximum value (S30). In Fig. 13, the underline indicating the first allowable range corresponds to the minimum value of the first allowable range, and the upper line corresponds to the maximum value of the first allowable range. The first permissible range means a range in which the measured value by the fuel pressure sensor 30, P (t _i ), can be regarded as being equal to the first pressure.

The method of sensing a fuel pressure sensor deterioration detection system according to an embodiment of the present invention is characterized in that the control unit 50 determines whether or not the measured pressure P (t _i ) corresponding to a certain measurement time is equal to a predetermined first minimum value (Not shown) for determining whether the second maximum value is between the first maximum value and the second maximum value.

Accordingly, the sensing method can monitor the pressure value measured every time by the controller 50, and the measured value P (t _i ) can be measured between the first predetermined minimum value and the first maximum value It can be determined that the pressure in the common rail has reached the first pressure. Immediately after the determination, the difference between the measured value P (t _{i + 1} ) and the next measured value P (t _{i + 1} ) may be calculated to perform S20, and S30 may be performed successively. The difference from the previously described point is that it is determined whether one measurement value P (t _i ) measured every hour is in the first pressure range (between the first predetermined minimum value and the first maximum value). S20 and S30 are performed only when it is determined that P (t _i ) is in the first pressure range.

A method of sensing a fuel pressure sensor deterioration detection system according to an embodiment of the present invention is characterized in that a larger pressure P (t _i ) among the two measured pressures P (t _i ), P (t _{i + 1} ) Is not within the first permissible range, the control unit (50) can output a deterioration warning signal of the fuel pressure sensor (30). In the embodiment of FIG. 12, the control unit 50 uses the warning signal to turn on the fuel pressure sensor error warning lamp (S40).

When in the above detection method, wherein two of the measured pressure (P (t _i), P (t _{i + 1))} greater pressure (P (t _i)) where the first permissible range of the control ( 50), the pressure in the common rail 10 can be continuously monitored. In the embodiment of FIG. 12, the controller 50 operates the high-pressure pump 20 (S50) and continues monitoring (S60).

In order to accurately determine whether the deterioration of the fuel pressure sensor 30 in the high pressure region has occurred or not in all the cases where the deterioration of the fuel pressure sensor 30 is detected or not in the low pressure region shown in FIG. (S60, S70).

Thus, the detection method, two of the measured pressure (P (t _k), P (t _{k + 1)} corresponding to the control by 50 and the two measuring times (t _k, t _{k + 1)} ) (in S60), and if the difference is greater than the second predetermined value, said two measured pressure by the control unit (50), (P (t _k), the difference comprising the steps of: determining whether more than a second set value of the , And determining whether the larger pressure P ( _tk ) out of the plurality of pressure P ( _{tk + 1} ) and P ( _{tk + 1} ) is within a second predetermined allowable range. These are the steps for sensing the second pressure located in the high pressure region.

The difference between the pressure values P ( _tk ) and P ( _{tk + 1} ) corresponding to two measurement times ( _tk , _{tk + 1} ) The control unit 50 can determine that the pressure in the common rail 10 has reached the second pressure, and accordingly, _calculate P (t _k ) as the measured value of the second pressure . Therefore, the second set value may be an arbitrary value exceeding the error range of the output signal of the fuel pressure sensor 30. This is because, when the pressure is reduced within the error range of the output signal, the pressure in the common rail 10 can not be determined to have reached the second pressure. As described above, a value that can sufficiently distinguish between the fluctuation of the fuel pressure generated when the fuel is pumped and the pressure fluctuation when the second check valve 42 is opened can be set to the second set value.

When it is determined by the controller 50 that the pressure in the common rail has reached the second pressure, the fuel pressure sensor 30 can be determined to be normal if P (t _k ) is within the second permissible range. On the other hand, if P (t _k ) is outside the second permissible range, the fuel pressure sensor 30 can be judged as deteriorated. 13 showing the low-pressure region can be directly applied to the description on the high-pressure region.

The second permissible range may be set as a minimum value and a maximum value (S70). The description corresponds to the description of the low-pressure region in Fig. 13, and therefore a detailed description thereof will be omitted.

The sensing method in the high-pressure region of the common rail 10 is characterized in that the controller 50 controls the controller 50 such that the measured pressure P ( _tk ) corresponding to a certain measurement time is greater than a predetermined second minimum value and a second maximum (Not shown) for determining whether the value is between the values.

Accordingly, the sensing method may monitor the pressure value measured every time by the controller 50, and the measured value P (t _k ) may be measured between the predetermined second minimum value and the second maximum value It can be determined that the pressure in the common rail 10 has reached the second pressure. Immediately after the determination, the difference between the next measured value P (t _{k + 1} ) and the next measured value P (t _{k + 1} ) may be calculated, S60 may be performed, and S70 may be performed consecutively. The difference from the foregoing is that it is determined whether one measurement value P (t _k ) to be measured every time is in the second pressure range (between the preset second minimum value and the second maximum value). S60 and S70 are performed only when it is determined that P ( _tk ) is in the second pressure range.

Detection method of a fuel pressure sensor deterioration detection system according to an embodiment of the present invention, wherein two of the measured pressure _{(P (t k), P} (t k + 1)) greater pressure (P (t _k)) of the Is not within the second permissible range, the controller (50) can output a deterioration warning signal of the fuel pressure sensor (30). In the embodiment of FIG. 12, the controller 50 turns on the fuel pressure sensor 30 error warning lamp using the warning signal (S40).

When in the above detection method, the two measured pressures _{(P (t k), P} (t k + 1)) greater pressure of (P (t _k)) the second permissible range, the controller ( 50, the deterioration diagnosis of the fuel pressure sensor 30 can be terminated. In the embodiment of FIG. 12, the controller 50 terminates the deterioration diagnosis and detection (S80).

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, And all changes to the scope that are deemed to be valid.

10: Common rail 20: High pressure pump
30: Fuel pressure sensor 40: Pressure limiting valve
41: first check valve 41a: first spring
41b: first valve cap 41c: first chamber
42: second check valve 42a: second spring
42b: second valve cap 42c: second chamber
50: control unit 60: injector

Claims (14)

delete A common rail for storing the compressed fuel and maintaining the pressure of the fuel;
A high pressure pump for compressing the fuel to supply the compressed fuel to the common rail;
A fuel pressure sensor for measuring the pressure of the fuel in the common rail;
A pressure restricting valve that reduces the pressure by a certain amount when the pressure of the fuel in the common rail reaches the first pressure and opens when reaching the second pressure which is larger than the first pressure; And
A control unit receiving the measurement signals of the fuel pressure sensor and sensing deterioration of the fuel pressure sensor;
Wherein the deterioration detection system of the fuel pressure sensor comprises:
The pressure-
A first check valve and a second check valve,
Wherein the first check valve and the second check valve,
Wherein the fuel pressure sensor is connected in series in series. 3. The method of claim 2,
The first check valve includes a first spring, a first valve cap, and a first chamber,
Wherein the second check valve comprises a second spring, a second valve cap, and a second chamber. The method of claim 3,
The first spring constant of the first spring and the second spring constant of the second spring are set such that the first check valve and the second check valve are opened at the first pressure and the second pressure, respectively Characterized by a fuel pressure sensor deterioration detection system. A common rail for storing the compressed fuel and maintaining the pressure of the fuel, a high-pressure pump for compressing the fuel to supply the compressed fuel to the common rail, a fuel pressure sensor for measuring the pressure of the fuel in the common rail, A pressure limiting valve which is opened when the pressure of the fuel reaches a first pressure and decreases when the pressure reaches a second pressure which is higher than the first pressure, And a control unit for detecting deterioration of the fuel pressure sensor,
Determining by the control unit whether a difference between two measured pressures corresponding to two measurement times exceeds a first set value; And
Determining, by the control unit, whether the greater of the two measured pressures is within a first predetermined allowable range if the difference exceeds the first set value;
And a fuel pressure sensor for detecting the deterioration of the fuel pressure sensor. 6. The method of claim 5,
Wherein the first permissible range includes:
Wherein the fuel pressure sensor is set to a minimum value and a maximum value. 6. The method of claim 5,
Determining by the control unit whether the measured pressure corresponding to a certain measurement time is between a first predetermined minimum value and a first predetermined maximum value;
Further comprising the steps of: detecting a fuel pressure in the fuel pressure sensor; 6. The method of claim 5,
Wherein the control unit outputs a deterioration warning signal of the fuel pressure sensor when the larger one of the two measured pressures is not within the first allowable range Way. 6. The method of claim 5,
Wherein the control unit continuously monitors the pressure in the common rail when a larger one of the two measured pressures is within the first allowable range. 10. The method according to claim 8 or 9,
Determining by the control unit whether a difference between two measured pressures corresponding to two measurement times exceeds a second set value; And
Determining, by the control unit, whether the greater of the two measured pressures is within a second predetermined allowable range if the difference exceeds the second set value;
Further comprising the steps of: detecting a fuel pressure in the fuel pressure sensor; 11. The method of claim 10,
Wherein the second permissible range includes:
Wherein the fuel pressure sensor is set to a minimum value and a maximum value. 11. The method of claim 10,
Determining by the control unit whether the measured pressure corresponding to a certain measurement time is between a second predetermined minimum value and a second maximum value;
Further comprising the steps of: detecting a fuel pressure in the fuel pressure sensor; 11. The method of claim 10,
Wherein the control unit outputs a deterioration warning signal of the fuel pressure sensor when a larger one of the two measured pressures is not within the second permissible range Way. 11. The method of claim 10,
Wherein the control unit terminates the deterioration detection of the fuel pressure sensor when a larger one of the two measured pressures is within the second allowable range.

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