JP2008014163A - Leak inspection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a leak inspection device achieving accurate leak inspection in a short time. <P>SOLUTION: The leak inspection device for inspecting leakage of evaporation fuel from an evaporation system 3 in which evaporation fuel generated inside a fuel tank is flowed to outside of the system 3 is provided with a reference hole 18 communicating with the evaporation system 3; a pump 20 communicating with the reference hole 18 ion the side opposite to the evaporation system 3 and executing inspection operation for applying pressure to the evaporation system 3 side of the reference hole 18 through the reference hole 18; a first detection means for detecting composition pressure loss ΔP which is the sum of inspection side pressure loss ΔPi generated in the evaporation system 3 by the inspection operation of the pump 20 and reference side pressure loss ΔPb generated in the reference hole 18 by the inspection operation of the pump 20; a second detection means for detecting either one of the inspection side pressure loss ΔPi and the reference side pressure loss ΔPb; and a determination means for determining leakage based on detection results by the first and second detection means. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a leak inspection apparatus for inspecting a leakage of evaporated fuel from an evaporation system through which evaporated fuel generated in a fuel tank flows.

Conventionally, there has been known a leak inspection apparatus that detects a pressure change due to a leak from both the reference hole and the evaporation system and a pressure change due to a leak only from the evaporation system, and determines the leak based on the detection results. . For example, in the leak inspection apparatus disclosed in Patent Document 1, the pressure to be detected is once lowered to a predetermined negative pressure value, and then the amount of pressure increase from the negative pressure value is detected to determine the leak.
Japanese Patent No. 3116556

  However, in the leak inspection apparatus disclosed in Patent Document 1, since the intake negative pressure of the internal combustion engine is used to temporarily reduce the pressure to be detected, when the intake negative pressure cannot be sufficiently obtained, The pressure drop takes time. In addition, the pressure rise after the pressure drop is generated by the negative pressure suction from a relatively small hole such as a reference hole or an evaporative leak hole. Takes a long time. For these reasons, it is difficult to shorten the leak inspection time.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a leak inspection apparatus that realizes an accurate and short-time leak inspection.

  According to the first aspect of the present invention, the inspection side pressure loss generated in the evaporation system by the inspection operation in which the pump applies pressure to the evaporation system side of the reference hole through the reference hole, and the pump is generated in the reference hole by the inspection operation. The magnitude relation with the reference side pressure loss to be changed varies depending on the magnitude relation between the leak hole of the evaporation system and the reference hole. Therefore, the result of detecting the combined pressure loss that is the sum of the inspection side pressure loss and the reference side pressure loss by the first detection means, and the result of detecting one of the inspection side pressure loss and the reference side pressure loss by the second detection means Based on this, it is possible to determine the magnitude of the leak from the leak hole. In addition, any pressure loss that is a detection target of each detection means can be quickly generated by the pressure action of the pump, so that the detection time of these pressure losses is shortened. Therefore, according to the first aspect of the present invention, a leak inspection can be realized accurately and in a short time.

  Note that the pressure acting on the evaporation system side of the reference hole through the reference hole by the inspection operation of the pump may be a negative pressure as in the invention of claim 2 or the invention of claim 3. Thus, a positive pressure may be used.

  According to the invention described in claim 4, since the pump is steadily operated at the time of performing the inspection operation, the fluctuation of the pressure loss detected by each detection means is suppressed, and the accuracy of the leak determination based on the pressure loss is increased. Can do.

  The difference between the detection result of the first detection means and the detection result of the second detection means is equal to the other of the inspection side pressure loss and the reference side pressure loss that is not detected by the second detection means. Therefore, according to the invention described in claim 5, the detection result of the second detection means is compared with the calculation result of the difference between the detection results of the detection means, that is, one of the inspection side pressure loss and the reference side pressure loss is regarded as the other. Since the comparison is made, it is possible to know the magnitude ratio between the leak hole of the evaporation system and the reference hole from the magnitude ratio of these pressure losses. Therefore, according to such a comparison, it is possible to accurately determine a leak from a leak hole that is larger than the reference hole.

  When the pump pressure is applied to the evaporation system side of the reference hole through the reference hole, the flow rates of fluid flowing through the evaporation system leak hole and the reference hole are equal to each other. It can be assumed that the magnitude of the loss and the reference side pressure loss are also equal. In addition, as the leak hole becomes larger, the inspection-side pressure loss tends to decrease. Therefore, according to the invention described in claim 6, when the inspection-side pressure loss is equal to or less than the reference-side pressure loss, it is determined that a leak has occurred. Therefore, an abnormal situation in which a leak occurs through a leak hole larger than the reference hole Can be determined correctly.

  As described above, when the size of the evaporation leak hole and the reference hole are equal, it can be assumed that the sizes of the inspection side pressure loss and the reference side pressure loss are also equal. Under this simulation, both the inspection side pressure loss and the reference side pressure loss are half the combined pressure loss. In addition, under this simulation, the inspection-side and reference-side pressure loss deviates from the half value of the combined pressure loss as the size ratio between the leak hole and the reference hole deviates from “1”. Therefore, according to the invention described in claim 7, the half value of the detection result of the first detection means is compared with the detection result of the second detection means, that is, the half value of the combined pressure loss and the inspection side or reference side pressure loss are compared. Since the comparison is made, the size ratio between the evaporative leak hole and the reference hole can be known from the comparison result. Therefore, according to such a comparison, it is possible to accurately determine a leak from a leak hole that is larger than the reference hole.

  According to the eighth aspect of the present invention, the pressure loss that is assumed to be generated in the reference hole by the inspection operation of the pump in the virtual state where the evaporation system side of the reference hole is opened to the atmosphere is defined as the pressure loss at the time of opening. Under this definition, the flow rate corresponding to the combined pressure loss in the pump pressure-flow rate characteristic (hereinafter referred to as PQ characteristic) is the flow rate corresponding to the pump cutoff pressure and the flow rate corresponding to the pressure loss during opening. It becomes the size between. Therefore, in the invention described in claim 8, the cutoff pressure of the pump equal to the opening pressure loss is equal to the combined pressure loss in which the corresponding flow rate is the magnitude between the corresponding closing flow and the opening pressure loss. Accordingly, the first detecting means according to the invention described in claim 8 detects the pump cutoff pressure as a combined pressure loss.

  Also, if there is a leak hole in the evaporation system, pressure loss will occur between the reference hole side of the evaporation system and the outside of the system when the pressure due to the pump inspection operation acts on the evaporation system side of the reference hole through the reference hole To do. Therefore, the second detection means according to the invention described in claim 8 detects the pressure difference between the reference hole side of the evaporation system and the outside of the system as an inspection-side pressure loss.

  The differential pressure sensor of the first detection means according to the invention described in claim 9 measures the difference between the pressure of the reference passage blocked by the switching means between the evaporation system and the pump and the atmospheric pressure, and the measurement result is It becomes equal to the cutoff pressure as a composite pressure loss. Therefore, the configuration necessary for detecting the combined pressure loss can be a relatively simple configuration using one differential pressure sensor.

  It can be said that the pressure between the evaporation system and the reference hole in the reference passage communicating with the evaporation system and forming the reference hole is the pressure on the reference hole side of the evaporation system. In general, since the leak inspection apparatus is used in the atmosphere, the pressure outside the evaporation system is atmospheric pressure. Accordingly, the differential pressure sensor of the second detection means according to the invention described in claim 10 measures the difference between the pressure between the evaporation system of the reference passage and the reference hole and the atmospheric pressure. It becomes equal to the pressure difference between the reference hole side of the system and the outside of the system. In addition, since the differential pressure sensor of the second detection means is the same as the differential pressure sensor of the first detection means, the configuration required for detecting both the inspection-side pressure loss and the combined pressure loss is reduced to one differential pressure sensor. It can be set as the comparatively simple structure used. Further, even if the reference passage is closed during measurement as the differential pressure sensor of the first detection means, it is opened by the opening / closing means during measurement as the differential pressure sensor of the second detection means. Through this, the pump pressure surely acts to the evaporation system. Therefore, the pressure difference as the inspection-side pressure loss can be accurately measured by a differential pressure sensor common to each detection means.

  The absolute pressure sensor of the first detecting means according to the eleventh aspect of the invention measures the absolute pressure of the reference passage closed by the opening / closing means between the evaporation system and the pump. Since this measurement result is equal to the sum of the cutoff pressure as the inspection-side pressure loss and the atmospheric pressure, it can be used to detect the combined pressure loss.

  It can be said that the absolute pressure between the evaporation system and the reference hole in the reference passage communicating with the evaporation system and forming the reference hole is the absolute pressure on the reference hole side of the evaporation system. In general, the evaporation system outside pressure is atmospheric pressure as described above. Therefore, in the second detection means according to the invention described in claim 12, the absolute pressure between the evaporation system of the reference passage and the reference hole is measured by the absolute pressure sensor, and the atmospheric pressure is measured by the atmospheric pressure sensor. The difference from the result is calculated, and the calculation result is equal to the pressure difference between the reference hole side of the evaporation system and the outside of the system. In addition, since the absolute pressure sensor of the second detection means is the same as the absolute pressure sensor of the first detection means, the configuration necessary for detecting both the inspection-side pressure loss and the combined pressure loss is reduced to one absolute pressure sensor. It can be set as the comparatively simple structure used. Further, even if the reference passage is closed during measurement as the absolute pressure sensor of the first detection means, it is opened by the opening / closing means during measurement as the absolute pressure sensor of the second detection means. Through this, the pump pressure surely acts to the evaporation system. Therefore, the absolute pressure reflecting the inspection-side pressure loss can be accurately measured even by an absolute pressure sensor common to each detection means.

  According to the invention described in claim 13, since the atmospheric pressure sensor measures the atmospheric pressure outside the reference passage, the atmospheric pressure sensor can be prevented from interfering with the absolute pressure measurement in the reference passage.

  According to the fourteenth aspect of the present invention, since the reference passage used for measuring the absolute pressure is opened to the atmosphere through the pump in a stopped state and used for measuring the atmospheric pressure, the number of parts of the device is reduced. This can contribute to simplification of the configuration and cost reduction.

  The absolute pressure measured by the absolute pressure sensor in the reference passage opened to the atmosphere is equal to the atmospheric pressure. Therefore, according to the invention described in claim 15, since the absolute pressure sensor also serves as an atmospheric pressure sensor for measuring the atmospheric pressure in the reference passage, the number of parts of the apparatus can be reduced to simplify the configuration and reduce the cost. You can go further.

  According to the sixteenth aspect of the present invention, the pressure loss generated in the reference hole by the inspection operation of the pump in a state where the evaporation system side of the reference hole is opened to the atmosphere by the opening control means is defined as the pressure loss at the time of opening. Under this definition, the flow rate corresponding to the combined pressure loss in the PQ characteristic of the pump is a magnitude between the flow rate corresponding to the open pressure loss and the flow rate corresponding to the pump cutoff pressure. Therefore, in the invention of the sixteenth aspect, the pressure loss at the time of opening equal to the shutoff pressure of the pump becomes equal to the combined pressure loss at which the corresponding flow rate is the magnitude between the corresponding flow rates of the opening pressure loss and the shutoff pressure. Accordingly, the first detecting means according to the invention of claim 16 detects the pressure loss during opening as the combined pressure loss.

  Further, when the pressure due to the inspection operation of the pump acts on the evaporation system side of the reference hole through the reference hole, pressure loss occurs on both sides of the reference hole. Therefore, the second detection means according to the invention described in claim 16 detects the pressure difference between both sides of the reference hole as the reference side pressure loss.

  The differential pressure sensor of the first detection means according to the seventeenth aspect of the invention measures the difference between the pressure on the evaporation system side of the reference hole opened to the atmosphere by the opening control means and the pressure on the pump side of the reference hole. Therefore, the measurement result is substantially equal to the opening pressure loss as the combined pressure loss. Therefore, the configuration necessary for detecting the combined pressure loss can be a relatively simple configuration using one differential pressure sensor.

  The differential pressure sensor of the second detection means according to the invention of claim 18 is characterized in that the difference between the pressure on the evaporation system side of the reference hole blocked from the atmosphere by the opening control means and the pressure on the pump side of the reference hole. Since it is measured, it can be said that the measurement result is a pressure difference between both sides of the reference hole. In addition, since the differential pressure sensor of the second detection means is the same as the differential pressure sensor of the first detection means, the configuration required for detecting both the reference side pressure loss and the combined pressure loss is reduced to one differential pressure sensor. It can be set as the comparatively simple structure used. Furthermore, even if the evaporation system side of the reference hole is opened to the atmosphere when measuring as the differential pressure sensor of the first detection means, it is blocked from the atmosphere by the opening / closing control means when measuring as the differential pressure sensor of the second detection means. The pump pressure surely acts to the evaporation system through the reference hole of the opened reference passage. Therefore, the pressure difference as the reference side pressure loss that occurs simultaneously with the inspection side pressure loss of the evaporation system on the pump pressure operating path can be accurately measured even by the differential pressure sensor common to each detection means.

  Hereinafter, a plurality of embodiments of the present invention will be described with reference to the drawings. In addition, the overlapping description is abbreviate | omitted by attaching | subjecting the same code | symbol to the corresponding component in each embodiment.

(First embodiment)
FIG. 1 shows an evaporated fuel processing apparatus 1 as a leak inspection apparatus according to a first embodiment of the present invention. The evaporated fuel processing apparatus 1 is mounted on a vehicle and processes evaporated fuel generated in the fuel tank 2. The evaporative fuel processing apparatus 1 includes an evaporation system 3, an inspection system 10, an electronic control unit (ECU) 50, and the like.

  The evaporation system 3 includes a fuel tank 2, a canister 8, an introduction passage 4, a purge passage 5, and a purge valve 6.

  The canister 8 is formed by filling an adsorbent 8 a such as activated carbon into the case 8 b and communicates with the fuel tank 2 through the introduction passage 4. Thus, the evaporated fuel generated in the fuel tank 2 flows into the case 8b of the canister 8 through the introduction passage 4, and is adsorbed by the adsorbent 8a so as to be desorbed.

  The purge passage 5 communicates between the canister 8 and the intake passage 9 of the internal combustion engine. Thereby, the evaporated fuel desorbed from the adsorbent 8 a of the canister 8 can be purged to the intake passage 9 through the purge passage 5. The evaporated fuel purged into the intake passage 9 is burned together with the injected fuel from the fuel injection valve in the internal combustion engine.

  The purge valve 6 is an electromagnetically driven two-way valve and is installed on the purge passage 5. The purge valve 6 adjusts the purge of the evaporated fuel into the intake passage 9 by opening and closing the purge passage 5.

  The inspection system 10 includes a reference passage 12, pressure guide passages 14 and 15, an atmospheric passage 16, a pump 20, a differential pressure sensor 30, and a switching valve 40.

  The reference passage 12 communicates with the canister 8 on the opposite side of the passages 4 and 5 across the adsorbent 8a. An orifice-shaped reference hole 18 is formed in the middle portion of the reference passage 12 to reduce the passage area. The passage area of the reference hole 18 is set to a value equal to or less than the total area of the leak holes allowed in the evaporation system 3 by law or the like. The atmospheric passage 16 is open to the atmosphere at one end thereof.

  The pump 20 is an electric pump, and is installed on the opposite side of the canister 8 with the reference passage 12 interposed therebetween. In the present embodiment, a pump 20 having a constant fluid suction / discharge direction is used, the suction port 22 of the pump 20 communicates with the reference passage 12, and the discharge port 24 of the pump 20 is opened to the atmosphere. ing. Thus, the pump 20 can perform an inspection operation (hereinafter simply referred to as an inspection operation) in which the reference passage 12 is decompressed and a negative pressure is applied to the evaporation system 3 side of the reference hole 18 through the reference hole 18.

  The differential pressure sensor 30 is an electric sensor that measures a pressure difference between the input ports 32 and 33. Here, one input port 32 communicates between the canister 8 and the reference hole 18 in the reference passage 12 through the pressure guide passage 14, and the other input port 33 is opened to the atmosphere through the pressure guide passage 15. Yes. Thus, the differential pressure sensor 30 measures the difference between the pressure between the evaporation system 3 and the reference hole 18 in the reference passage 12 and the atmospheric pressure outside the evaporation system 3. Here, since the pressure between the evaporation system 3 and the reference hole 18 in the reference passage 12 is also the pressure on the reference hole 18 side of the evaporation system 3, the measurement target of the differential pressure sensor 30 is the system between the reference hole 18 side of the evaporation system 3 and the system. It can be said that it is a pressure difference with the outside.

  The switching valve 40 is an electromagnetically driven three-way valve, is installed between the canister 8 on the reference passage 12 and the pressure guide passage 14 and is connected to the end of the atmosphere passage 16 opposite to the atmosphere opening end. The switching valve 40 switches a passage communicating with the evaporation system side passage portion 12 a of the reference passage 12 between the pump side passage portion 12 b of the reference passage 12 and the atmospheric passage 16. Therefore, in the first state where the switching valve 40 communicates the atmospheric passage 16 with the evaporation system side passage portion 12a as shown in FIG. 1, the reference passage 12 is closed on the suction side of the pump 20 and the canister 8 is brought into the atmosphere. On the other hand, it is released. On the other hand, as shown in FIG. 2, in the second state where the switching valve 40 communicates the pump side passage portion 12 b with the evaporation system side passage portion 12 a, the reference passage 12 is opened and the canister 8 is pumped through the reference passage 12. Communicate with.

  The ECU 50 is mainly composed of a microcomputer having a CPU and a memory. The ECU 50 is electrically connected to the valves 6, 40, the pump 20, and the differential pressure sensor 30, and controls the operation of these electrical connection elements. The ECU 50 may have a control function for the internal combustion engine, or may not have such a control function.

  Next, the principle of inspection for leakage from the evaporation system 3 to the outside of the system jointly performed by the inspection system 10 and the ECU 50 will be described.

  As shown in FIG. 2, when the pump 20 performs an inspection operation in the second state in which the switching valve 40 opens the reference passage 12 between the evaporation system 3 and the pump 20, negative pressure is applied through the reference hole 18 of the passage 12. It acts on the evaporation system 3 side of the reference hole 18. As a result, when the leak hole 60 exists in the evaporation system 3 as schematically shown in FIG. 3A, the pump 20 is sequentially passed from the outside of the evaporation system 3 through the leak hole 60 and the reference hole 18. A fluid flow toward is generated. The pressure loss ΔPi generated in the evaporation system 3 at this time can be expressed by a pressure difference between the reference hole 18 side of the evaporation system 3 and the outside of the system. Further, at this time, the pressure loss ΔPb generated in the reference passage 12 can be expressed by a pressure difference (so-called differential pressure before and after) on both sides of the reference hole 18.

Normally, the leak hole 60 that causes a leak is smaller than the passage area of the evaporation system 3, so that the pressure loss ΔPi that occurs in the evaporation system 3 due to the inspection operation of the pump 20 is dominated by the pressure loss that occurs in the leakage hole 60. Become. Therefore, it can be considered that the pressure loss ΔPi in the evaporation system 3 is substantially equal to the pressure loss in the leak hole 60, and the correlation between the pressure loss ΔPi and the flow rate Qi in the leak hole 60 is expressed by the following equation (1). It is expressed as In equation (1), αi represents the flow coefficient of the leak hole 60, Ai represents the total area of the leak hole 60, and ρi represents the density of the circulating fluid in the leak hole 60.
Qi = αi · Ai · (2 · ΔPi / ρi) ^1/2 (1)

Since the reference hole 18 restricts the passage area of the reference passage 12, the pressure loss ΔPb generated in the reference passage 12 due to the inspection operation of the pump 20 is dominated by the pressure loss generated in the reference hole 18. Therefore, it can be considered that the pressure loss ΔPb in the reference passage 12 is substantially equal to the pressure loss in the reference hole 18, and the correlation between the pressure loss ΔPb and the flow rate Qb in the reference hole 18 is expressed by the following equation (2). It is expressed as In equation (2), αb represents the flow coefficient of the reference hole 18, Ab represents the passage area of the reference hole 18, and ρb represents the density of the circulating fluid in the reference hole 18.
Qb = αb · Ab · (2 · ΔPb / ρb) ^1/2 (2)

When the above-described fluid flow is generated by the inspection operation of the pump 20, the flow rate Qi in the leak hole 60 and the flow rate Qb in the reference hole 18 coincide. Therefore, the following formula (3) is obtained from the above formulas (1) and (2), and the following formula (4) is obtained by rearranging the formula (3).
αi · Ai · (2 · ΔPi / ρi) ^1/2 = αb · Ab · (2 · ΔPb / ρb) ^1/2 (3)
ΔPi / ΔPb = ρi / ρb · {(αb · Ab) / (αi · Ai)} ² (4)

In the above equation (4), assuming that the fluid densities ρi and ρb are approximately equal as in the following equation (5), the following equation (6) is established when the sizes of the holes 18 and 60 are equal: The value of the magnitude ratio ΔPi / ΔPb is “1”. Further, according to the above equation (4), the value of the magnitude ratio ΔPi / ΔPb decreases as the total area Ai of the leak holes 60 increases. Therefore, when the value of the magnitude ratio ΔPi / ΔPb is “1” or less, that is, when the pressure loss ΔPi is equal to or less than the pressure loss ΔPb, leakage occurs from the leak hole 60 larger than the reference hole 18. Judge that there is. Further, when the value of the magnitude ratio ΔPi / ΔPb exceeds “1”, that is, when the pressure loss ΔPi is larger than the pressure loss ΔPb, it is determined that no leak occurs from the leak hole 60. As described above, in this embodiment, the pressure loss ΔPi is defined as the inspection-side pressure loss ΔPi, and the pressure loss ΔPb is defined as the reference-side pressure loss ΔPb.
ρi≈ρb (5)
αi · Ai = αb · Ab (6)

  In order to determine a leak from the magnitude ratio ΔPi / ΔPb as described above, it is important to accurately know the inspection side and reference side pressure losses ΔPi and ΔPb. Therefore, in this embodiment, after detecting the combined pressure loss ΔP (see FIG. 3), which is the sum of the inspection side pressure loss ΔPi and the reference side pressure loss ΔPb, and the inspection side pressure loss ΔPi, respectively, the detected combined pressure loss is detected. The reference side pressure loss ΔPb is calculated from the difference between ΔP and the inspection side pressure loss ΔPi.

  Here, in the detection of the combined pressure loss ΔP, the measurement result of the differential pressure sensor 30 under a specific condition is used by using the pump 20 having the characteristics as shown in FIG. Specifically, in the PQ characteristics of the pump 20 shown in FIG. 4, as shown schematically in FIG. 3B, the pump 20 is inspected in a virtual state in which the evaporation system 3 side of the reference hole 18 is opened to the atmosphere. An opening pressure loss ΔPo that is assumed to be generated in the reference hole 18 is equal to a cutoff pressure Pt that is a generated pressure of the pump 20 that is closed on the suction side. In other words, the PQ characteristic curve of the pump 20 is a straight line with a constant pressure at least between the cutoff pressure Pt and the opening pressure loss ΔPo. Therefore, as shown in FIG. 4, the combined pressure loss ΔP in which the corresponding flow rate Qp is between the corresponding flow rate 0 of the cutoff pressure Pt and the corresponding flow rate Qo of the opening pressure loss ΔPo is also equal to ΔPo, Pt. Therefore, in the present embodiment, as shown in FIG. 1, the difference between the pressure of the pump side passage portion 12b and the atmospheric pressure in the first state where the switching valve 40 closes the suction side reference passage 12 of the pump 20, that is, the cutoff pressure Pt. Is measured by the differential pressure sensor 30, and the measured cutoff pressure Pt is detected as a combined pressure loss ΔP.

  Further, in the detection of the inspection side pressure loss ΔPi represented by the pressure difference between the reference hole 18 side of the evaporation system 3 and the outside of the system, the second state in which the switching valve 40 opens the reference passage 12 as shown in FIG. The measurement result of the differential pressure sensor 30 is used as it is.

  Based on the above, accurate leak determination based on the detected pressure losses ΔP and ΔPi is possible. Therefore, the leak inspection process according to the first embodiment in accordance with the above principle will be described below with reference to the flowchart of FIG. The leak inspection process is started after the internal combustion engine is stopped by the ECU 50 executing a computer program stored in the memory. At the start of the leak inspection process, the purge valve 6 is in the closed state of the purge passage 5, the pump 20 is in the stopped state, and the switching valve 40 is in the first state in which the reference passage 12 is closed.

  First, in step S101, the inspection operation of the pump 20 is started under the control of the ECU 50.

  Next, in step S102, the cutoff pressure Pt of the pump 20 is measured by the differential pressure sensor 30, and the measurement result is detected by the ECU 50 as a combined pressure loss ΔP. In the subsequent step S103, the ECU 50 controls the switching valve 40 to realize the second state in which the reference passage 12 is opened, and the pump pressure is applied to every corner of the evaporation system 3. In the subsequent step S104, the pressure difference between the reference hole 18 side of the evaporation system 3 and the outside of the system is measured by the differential pressure sensor 30, and the measurement result is detected by the ECU 50 as the inspection side pressure loss ΔPi. In steps S102 to S104 of the present embodiment, the pump 20 is steadily operated under the control of the ECU 50 at least during measurement by the differential pressure sensor 30. Here, the steady operation of the pump 20 may be realized, for example, by controlling the rotational speed of the pump 20, may be realized by controlling the supply voltage to the pump 20, or may be realized by controlling the supply current to the pump 20. May be.

  In step S105 after the combined and inspection side pressure losses ΔP and ΔPi are thus detected, the ECU 50 calculates the reference side pressure loss ΔPb from the difference between the pressure losses ΔP and ΔPi. In step S106, the ECU 50 compares the inspection-side pressure loss ΔPi detected in step S104 with the reference-side pressure loss ΔPb calculated in step S105, thereby determining leakage from the evaporation system 3. Specifically, if the inspection-side pressure loss ΔPi is equal to or less than the reference-side pressure loss ΔPb, it is determined that a leak has occurred, and step S107 is executed. Then, the process proceeds to step S108. Here, in step S107, the occurrence of a leak is notified to the user of the vehicle, for example, by lighting an abnormal lamp on the instrument panel of the vehicle. On the other hand, if the inspection-side pressure loss ΔPi is larger than the reference-side pressure loss ΔPb, it is determined that no leak has occurred, and the process directly proceeds to step S108.

  In step S108, which is executed regardless of the leak determination result, the inspection operation of the pump 20 is stopped under the control of the ECU 50. At the same time, in step S108, the switching valve 40 is returned to the first state under the control of the ECU 50, and the reference passage 12 is closed.

  According to the first embodiment described above, since both the combined and inspection-side pressure losses ΔP and ΔPi can be generated quickly by the pressure action of the pump 20, the time required for detecting these pressure losses ΔP and ΔPi. Can be shortened.

  Further, according to the first embodiment, the characteristics of the pump 20 as shown in FIG. 4 can be realized by a relatively inexpensive non-displacement pump such as a centrifugal pump, which contributes to cost reduction. It becomes possible.

  Furthermore, in the first embodiment, since the pressure losses ΔP and ΔPi generated by the steady operation of the pump 20 are detected, it is possible to prevent the leak determination accuracy from deteriorating due to the characteristic variation of the pump 20 or the like.

  In the first embodiment, the pressure difference detected as the pressure losses ΔP and ΔPi is measured by the common differential pressure sensor 30, so that the configuration necessary for detecting these pressure losses ΔP and ΔPi is relatively simple. can do.

  In the first embodiment described so far, the differential pressure sensor 30 and the ECU 50 jointly constitute the “first detection means” recited in the claims, and the differential pressure sensor 30 and the ECU 50 jointly. The “second detection means” described in the claims is also configured. Further, in the first embodiment, the ECU 50 corresponds to a “detection difference calculation unit” and a “comparison / determination unit” described in the claims, and “determination means” including them, and the switching valve 40 is defined in the claims. It corresponds to the “opening and closing means” described in 1.

(Second embodiment)
As shown in FIG. 6, the second embodiment of the present invention is a modification of the first embodiment. In the second embodiment, an absolute pressure sensor 100 and an atmospheric pressure sensor 110 are provided instead of the differential pressure sensor 30, and the pressure guiding passage 15 is omitted accordingly.

  The absolute pressure sensor 100 is an electric sensor that measures the absolute pressure of the input port 102. Here, the input port 102 communicates with the reference passage 12 through the pressure guide passage 14. Thus, the absolute pressure sensor 100 measures the absolute pressure between the evaporation system 3 and the reference hole 18 in the reference passage 12, in other words, the absolute pressure on the reference hole 18 side of the evaporation system 3.

  The atmospheric pressure sensor 110 is an electric sensor that measures an absolute pressure outside the evaporation system 3, that is, an atmospheric pressure. The atmospheric pressure sensor 110 is installed outside the reference passage 12 at an appropriate location according to the specifications of the evaporated fuel processing apparatus 1 and measures the atmospheric pressure at the installation location.

  The absolute pressure sensor 100 and the atmospheric pressure sensor 110 are electrically connected to the ECU 50. The ECU 50 detects the absolute pressure (hereinafter referred to as the first absolute pressure) of the pump side passage portion 12b measured by the absolute pressure sensor 100 in the first state where the switching valve 40 closes the reference passage 12, as shown in FIG. Then, the sum of the cutoff pressure Pt and the atmospheric pressure is indirectly detected as the sum of the combined pressure loss ΔP and the atmospheric pressure. Further, the ECU 50 detects the absolute pressure on the reference hole 18 side of the evaporation system 3 measured by the absolute pressure sensor 100 in the second state in which the switching valve 40 opens the reference passage 12 as shown in FIG. And the atmospheric pressure outside the evaporation system 3 measured by the atmospheric pressure sensor 110 is calculated. This calculation result is equal to the measurement result of the differential pressure sensor 30 detected as the inspection-side pressure loss ΔPi in the first embodiment. Further, the ECU 50 calculates the difference between the first and second absolute pressures measured by the absolute pressure sensor 100. This calculation result becomes equal to the difference between the combined pressure loss ΔP and the inspection side pressure loss ΔPi calculated in the first embodiment, that is, the reference side pressure loss ΔPb.

  As described above, since the ECU 50 can obtain the inspection-side pressure loss ΔPi and the reference-side pressure loss ΔPb, accurate leak determination can be performed. Accordingly, the leak inspection process of the second embodiment will be described below with reference to the flowchart of FIG.

  First, in step S <b> 201, the atmospheric pressure is measured by the atmospheric pressure sensor 110. The next step S202 is the same as step S101 of the first embodiment.

  In subsequent step S203, the first absolute pressure is measured by the absolute pressure sensor 100, and the measurement result is detected by the ECU 50 as the sum of the combined pressure loss ΔP and the atmospheric pressure. Furthermore, after execution of step S204 similar to step S103 of the first embodiment, steps S205 and S206 are executed. Here, in step S <b> 205, the second absolute pressure is measured by the absolute pressure sensor 100. In step S206, the ECU 50 calculates a difference between the second absolute pressure measured in step S205 and the atmospheric pressure measured in step S201, and detects the calculation result as an inspection-side pressure loss ΔPi. In steps S203 to S206 of the present embodiment, the pump 20 is steadily operated under the control of the ECU 50 at least during measurement by the absolute pressure sensor 100.

  In step S207, the ECU 50 calculates the reference side pressure loss ΔPb from the difference between the first and second absolute pressures measured in steps S203 and S205. This process is equivalent to calculating the reference side pressure loss ΔPb from the difference between the combined and inspection side pressure losses ΔP and ΔPi. Subsequent steps S208 to S210 are the same as steps S106 to S108 of the first embodiment.

  As described above, in the second embodiment, the first and second absolute pressures are measured by the common absolute pressure sensor 100, and the absolute pressure sensor 100 is generally less expensive than the differential pressure sensor. This can contribute to simplification and cost reduction.

  In the second embodiment, since the atmospheric pressure sensor 110 measures the atmospheric pressure outside the reference passage 12, the atmospheric pressure sensor 110 can be prevented from interfering with the measurement of the first and second absolute pressures.

  In the second embodiment described above, the absolute pressure sensor 100 and the ECU 50 jointly constitute the “first detection means” recited in the claims, and the absolute pressure sensor 100 and the atmospheric pressure sensor 110 The ECU 50 and the ECU 50 together constitute “second detection means” described in the claims. Furthermore, in the second embodiment, the ECU 50 corresponds to a “measurement difference calculation unit” described in the claims.

(Third embodiment)
As shown in FIGS. 9 and 10, the third embodiment of the present invention is a modification of the second embodiment. In the third embodiment, the atmospheric pressure sensor 110 is not provided, and a part of the content of the leak inspection process is different from the second embodiment.

  Specifically, in the leak inspection process of the third embodiment, the first absolute pressure is measured by the absolute pressure sensor 100 in step S301 instead of step S201 of the second embodiment. At this time, the pump 20 is in the same stop state as at the start of the process, and the reference passage 12 is opened to the atmosphere through the pump 20, so that the first absolute pressure to be measured becomes equal to the atmospheric pressure. Subsequent steps S302 to S310 are the same as steps S202 to S210 of the second embodiment.

  As described above, in the third embodiment, not only the first and second absolute pressures but also the atmospheric pressure is measured by the common absolute pressure sensor 100. In the third embodiment, the reference passage 12 used for measuring the first and second absolute pressures is also used for measuring the atmospheric pressure. From these things, according to 3rd embodiment, the number of parts of the evaporative fuel processing apparatus 1 can be reduced, and the simplification of a structure and reduction of cost can be aimed at.

  In the third embodiment described above, the absolute pressure sensor 100 that measures the atmospheric pressure corresponds to the “atmospheric pressure sensor” recited in the claims.

(Fourth embodiment)
As shown in FIG. 11, the fourth embodiment of the present invention is a modification of the first embodiment. In the fourth embodiment, one input port 202 of the differential pressure sensor 200 is the same as the input port 32 of the first embodiment, but the other input port 203 is connected to the reference hole 18 in the reference passage 12 through the pressure guide passage 204 and There is communication between the pumps 20. Thereby, the differential pressure sensor 200 measures the pressure difference between both sides of the reference hole 18 in the reference passage 12, that is, the difference between the evaporation system 3 side pressure of the reference hole 18 and the pump 20 side pressure.

  Further, in the fourth embodiment, the switching valve 40 is not provided, and the end of the atmosphere passage 210 opposite to the atmosphere opening end is directly communicated with the boundary portion of each passage portion 12a, 12b of the reference passage 12, and this atmosphere An opening control valve 220 is installed in the passage 210. The opening control valve 220 is an electromagnetically driven two-way valve and is electrically connected to the ECU 50. The opening control valve 220 opens or closes the evaporation system 3 side of the reference hole 18 in the reference passage 12 with respect to the atmosphere by opening and closing the atmosphere passage 210 according to the control of the ECU 50.

  In the fourth embodiment having such a configuration, after detecting the combined pressure loss ΔP and the reference side pressure loss ΔPb, the leak is determined by directly comparing the pressure losses ΔP and ΔPb.

  Here, in the detection of the combined pressure loss ΔP, the measurement result of the differential pressure sensor 200 under a condition different from that of the first embodiment is used by using the pump 20 having the same characteristics as the first embodiment. Specifically, in the case of this embodiment, when the evaporation system 3 side of the reference hole 18 is opened to the atmosphere, the opening pressure loss ΔPo generated in the reference hole 18 by the inspection operation of the pump 20 and the suction side are blocked. The cutoff pressure Pt, which is the pressure generated by the pump 20, becomes equal (see FIG. 4). Accordingly, since the combined pressure loss ΔP becomes equal to the opening pressure loss ΔPo and the cutoff pressure Pt, in the case of this embodiment, the reference hole in a state in which the opening control valve 220 opens the evaporation system 3 side of the reference hole 18 to the atmosphere. 18 is measured by the differential pressure sensor 200. Then, the measured opening pressure loss ΔPo is detected as a combined pressure loss ΔP.

  Further, in the detection of the reference side pressure loss ΔPb represented by the pressure difference between both sides of the reference hole 18, the differential pressure sensor 200 in a state where the open control valve 220 blocks the evaporation system 3 side of the reference hole 18 from the atmosphere. The measurement results are used as they are.

Furthermore, the leak determination by direct comparison of the pressure losses ΔP and ΔPb is substantially equivalent to the leak determination from the magnitude ratio ΔPi / ΔPb described in the first embodiment. That is, when the sizes of the reference hole 18 and the leak hole 60 are equal under the pseudo control as in the above formula (5), the value of the magnitude ratio ΔPi / ΔPb becomes “1”. Means equal. Here, since the combined pressure loss ΔP is the sum of the pressure losses ΔPi and ΔPb, when the reference hole 18 and the leak hole 60 have the same size, the following formula (7) is established. Further, as the total area Ai of the leak hole 60 increases, the value of the magnitude ratio ΔPi / ΔPb tends to decrease. In this case, the value on the left side in the following formula (7) tends to increase with respect to the value on the right side. Show. Accordingly, in the present embodiment, when the reference side pressure loss ΔPb is greater than or equal to the half value of the combined pressure loss ΔP, it is determined that there is a leak, and the reference side pressure loss ΔPb is determined to be the combined pressure loss ΔP. If it is smaller than the half value of, it is determined that no leak occurs.
ΔPb = ΔP / 2 (7)

  According to the above, accurate leak determination based on the detected pressure losses ΔP and ΔPb becomes possible. Accordingly, the leak inspection process of the fourth embodiment will be described below with reference to the flowchart of FIG. At the start of the leak inspection process, it is assumed that the purge valve 6 is in the closed state of the purge passage 5, the pump 20 is in the stopped state, and the opening control valve 220 is in the state in which the evaporation system 3 side of the reference hole 18 is open to the atmosphere.

  First, step S401 is the same as step S101 of the first embodiment.

  In the next step S402, the opening pressure loss ΔPo is measured by the differential pressure sensor 200, and the measurement result is detected by the ECU 50 as a combined pressure loss ΔP. In the subsequent step S403, the ECU 50 controls the opening control valve 220 to block the evaporation system 3 side of the reference hole 18 from the atmosphere, so that the pump pressure is applied to every corner of the evaporation system 3. In further subsequent step S404, the pressure difference between both sides of the reference hole 18 is measured by the differential pressure sensor 200, and the measurement result is detected by the ECU 50 as the reference side pressure loss ΔPb. In steps S402 to S404 of the present embodiment, the pump 20 is steadily operated under the control of the ECU 50 at least during measurement by the differential pressure sensor 200.

  In step S405 after the combined and reference side pressure losses ΔP and ΔPb are detected in this way, the ECU 50 compares the pressure losses ΔP and ΔPb to determine leakage from the evaporation system 3. Specifically, if the reference-side pressure loss ΔPb is equal to or greater than the half value of the combined pressure loss ΔP, it is determined that a leak has occurred, and after executing step S406, the process proceeds to step S407. On the other hand, if the reference side pressure loss ΔPb is smaller than the half value of the combined pressure loss ΔP, it is determined that no leak has occurred, and the process directly proceeds to step S407.

  Step S406 is the same as step S107 in the first embodiment. Step S407 is the first implementation except that the opening control valve 220 is returned to the atmospheric release state on the evaporation system 3 side of the reference hole 18 instead of returning the switching valve 40 to the first state under the control of the ECU 50. This is the same as step S108 of the embodiment.

  As described above, according to the fourth embodiment, since both the combined and reference side pressure losses ΔP and ΔPb can be generated quickly by the pressure action of the pump 20, the time required for detecting these pressure losses ΔP and ΔPb. Can be shortened.

  Further, according to the fourth embodiment, it is possible to use the open control valve 220 including an on / off valve that is less expensive than the switching valve, which can contribute to cost reduction.

  Further, in the fourth embodiment, the pressure loss ΔP, ΔPb generated by the steady operation of the pump 20 is detected to prevent deterioration of the leak determination accuracy, and the pressure difference detected as the pressure loss ΔP, ΔPb is set as a common difference. Measurement by the pressure sensor 30 can contribute to simplification of the configuration.

  In the fourth embodiment described above, the differential pressure sensor 200 and the ECU 50 jointly constitute the “first detection means” recited in the claims, and the differential pressure sensor 200 and the ECU 50 jointly operate. The “second detection means” described in the claims is also configured. Further, in the fourth embodiment, the ECU 50 is a “determination unit” described in the claims, such as determining a leak by comparing the half value of the detection result of the first detection unit with the detection result of the second detection unit. The opening control valve 220 corresponds to the “opening control means” described in the claims.

(Other embodiments)
Although a plurality of embodiments of the present invention have been described so far, the present invention is not construed as being limited to these embodiments, and can be applied to various embodiments without departing from the scope of the present invention. be able to.

  For example, in the first to fourth embodiments, as shown in FIG. 13 (the figure is an example of the first embodiment), the discharge port 24 is communicated with the reference passage 12 in the pump 20 with a constant fluid suction / discharge direction. At the same time, the suction port 22 may be opened to the atmosphere. In this case, when the pump 20 is inspected, positive pressure acts on the evaporation system 3 side of the reference hole 18 through the reference hole 18, and therefore when the leak hole 60 exists in the evaporation system 3, the reference hole 18 and the leak from the pump 20. A fluid flow toward the outside of the evaporation system 3 is generated via the holes 60 sequentially. In the first to fourth embodiments, a pump having a variable fluid suction / discharge direction may be used in place of the pump 20. Furthermore, in the first to fourth embodiments, the pump 20 may not be steadily operated during the inspection operation. Furthermore, in the first to fourth embodiments, the fuel vapor state such as the fuel vapor concentration may be measured using the inspection system 10 or the ECU 50, or the purge to the intake passage 9 may be assisted using the pump 20. May be.

  In the first to third embodiments, instead of detecting the inspection side pressure loss ΔPi after detecting the combined pressure loss ΔP as described above, the combined pressure loss ΔP is detected after detecting the inspection side pressure loss ΔPi. Also good. In the first to third embodiments, in order to further improve the determination accuracy of the leak, by grasping the magnitude ratio of the pressure loss ΔPi, ΔPb by the above formula (4) considering the ratio of the fluid density ρi, ρb, A leak may be determined. Furthermore, in the first to third embodiments, the leak may be determined by directly comparing the combined pressure loss ΔP and the inspection-side pressure loss ΔPi according to the second embodiment.

  In the second and third embodiments, in step S203, the first absolute pressure is measured by the absolute pressure sensor 100, and the difference between the measurement result and the atmospheric pressure measured in step S201 is directly used as the combined pressure loss ΔP. It may be detected. In this case, the absolute pressure sensor 100, the atmospheric pressure sensor 110, and the ECU 50 jointly constitute the “first detection means” described in the claims.

  In the third embodiment, the atmospheric pressure sensor 110 of the second embodiment may be installed in the reference passage 12 and the atmospheric pressure may be measured by the atmospheric pressure sensor 110.

  In the fourth embodiment, instead of detecting the reference side pressure loss ΔPb after detecting the combined pressure loss ΔP as described above, the combined pressure loss ΔP may be detected after detecting the reference side pressure loss ΔPb. Further, in the fourth embodiment, in order to further improve the determination accuracy of the leak, the above equation (7) is modified to reflect the ratio of the fluid densities ρi, ρb, and the pressure loss ΔP, ΔPb is compared by the modified equation. The leak may be determined by doing so. Furthermore, in the fourth embodiment, after calculating the inspection-side pressure loss ΔPi from the difference between the combined pressure loss ΔP and the reference-side pressure loss ΔPb according to the first embodiment, the leak is determined from the ratio of the pressure losses ΔPi and ΔPb. May be.

It is a schematic diagram which shows the structure of the evaporative fuel processing apparatus by 1st embodiment. It is a schematic diagram for demonstrating the action | operation of the evaporative fuel processing apparatus shown in FIG. It is a schematic diagram for demonstrating the inspection principle of a leak. It is a schematic diagram for demonstrating the inspection principle of a leak. It is a flowchart which shows the leak test process by 1st embodiment. It is a schematic diagram which shows the structure of the evaporative fuel processing apparatus by 2nd embodiment. It is a schematic diagram for demonstrating the action | operation of the evaporative fuel processing apparatus shown in FIG. It is a flowchart which shows the leak test process by 2nd embodiment. It is a schematic diagram which shows the structure of the evaporative fuel processing apparatus by 3rd embodiment. It is a flowchart which shows the leak test process by 3rd embodiment. It is a schematic diagram which shows the structure of the evaporative fuel processing apparatus by 4th embodiment. It is a flowchart which shows the leak test process by 4th embodiment. It is a schematic diagram which shows the structure of a modification.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Evaporative fuel processing apparatus (leak inspection apparatus), 2 Fuel tank, 3 Evaporation system, 10 Inspection system, 12 Reference | standard passage, 12a Evaporation system side channel | path part, 12b Pump side channel | path part, 14, 15, 204 Pressure-guide path, 16 , 210 air passage, 18 reference hole, 20 pump, 22 suction port, 24 discharge port, 30, 200 differential pressure sensor (first detection means, second detection means), 40 switching valve (opening / closing means), 50 ECU ( First detection means, second detection means, determination means, detection difference calculation section, comparison determination section, measurement difference calculation section), 60 leak hole, 100 absolute pressure sensor (first detection means, second detection means, atmospheric pressure sensor) ), 110 atmospheric pressure sensor (second detection means), 220 open control valve (open control means), ΔPb reference side pressure loss, ΔPi inspection side pressure loss, ΔPi / ΔPb magnitude ratio, ΔP composite pressure Power loss, ΔPo Opening pressure loss, Pt cutoff pressure

Claims (18)

A leak inspection apparatus for inspecting a leak of evaporated fuel from an evaporation system through which evaporated fuel generated in a fuel tank flows,
A reference hole communicating with the evaporation system;
A pump that communicates with the reference hole on the opposite side of the evaporation system, and performs an inspection operation that applies pressure to the evaporation system side of the reference hole through the reference hole;
First detection means for detecting a combined pressure loss that is a sum of an inspection-side pressure loss generated in the evaporation system by the inspection operation and a reference-side pressure loss generated in the reference hole by the inspection operation;
Second detection means for detecting one of the inspection-side pressure loss and the reference-side pressure loss;
Determination means for determining the leak based on the detection result of the first detection means and the detection result of the second detection means;
A leak inspection apparatus comprising:   The leak inspection apparatus according to claim 1, wherein the pressure acting on the evaporation system side of the reference hole through the reference hole by the inspection operation is a negative pressure.   The leak inspection apparatus according to claim 1, wherein the pressure acting on the evaporation system side of the reference hole through the reference hole by the inspection operation is a positive pressure.   The leak inspection apparatus according to any one of claims 1 to 3, wherein the pump is steadily operated when the inspection operation is performed. The determination means includes
A detection difference calculation unit for calculating a difference between the detection result of the first detection unit and the detection result of the second detection unit;
A comparison determination unit that compares the detection result of the second detection unit with the calculation result of the calculation unit to determine the leak;
The leak inspection apparatus according to claim 1, wherein the leak inspection apparatus includes:   In the comparison determination unit, the inspection-side pressure loss which is one of the detection result of the second detection unit and the calculation result of the calculation unit is the other of the detection result of the second detection unit and the calculation result of the calculation unit. The leak inspection apparatus according to claim 5, wherein the leak is determined to be generated when the pressure loss is equal to or less than the reference-side pressure loss.   5. The determination unit according to claim 1, wherein the determination unit determines the leak by comparing a half value of a detection result of the first detection unit with a detection result of the second detection unit. The described leak inspection apparatus. The cutoff pressure of the pump is equal to the pressure loss at the time of opening assumed to be generated in the reference hole by the inspection operation in a virtual state where the evaporation system side of the reference hole is opened to the atmosphere.
The first detection means detects the cutoff pressure as the combined pressure loss,
The said 2nd detection means detects the pressure difference of the said reference | standard hole side of the said evaporation system, and the said system outside as said test | inspection side pressure loss, It is any one of Claims 1-7 characterized by the above-mentioned. Leak inspection device. A reference passage provided between the evaporation system and the pump and forming the reference hole;
Opening and closing means for opening and closing the reference passage;
With
9. The leak inspection apparatus according to claim 8, wherein the first detection unit includes a differential pressure sensor that measures a difference between a pressure of the reference passage blocked by the opening / closing unit and an atmospheric pressure.   The second detection means is the differential pressure sensor that is common to the first detection means, and includes a pressure between the evaporation system and the reference hole of the reference passage opened by the opening / closing means, and an atmospheric pressure. The leak inspection apparatus according to claim 9, further comprising the differential pressure sensor that measures a difference. A reference passage provided between the evaporation system and the pump and forming the reference hole;
Opening and closing means for opening and closing the reference passage;
With
The leak inspection apparatus according to claim 8, wherein the first detection unit includes an absolute pressure sensor that measures an absolute pressure of the reference passage blocked by the opening / closing unit. The second detection means includes
The absolute pressure sensor common to the first detection means, the absolute pressure sensor for measuring the absolute pressure between the evaporation system of the reference passage opened by the opening and closing means and the reference hole;
An atmospheric pressure sensor for measuring atmospheric pressure;
A measurement difference calculation unit for calculating a difference between the measurement result of the absolute pressure sensor and the measurement result of the atmospheric pressure sensor;
The leak inspection apparatus according to claim 11, further comprising:   The leak inspection apparatus according to claim 12, wherein the atmospheric pressure sensor measures an atmospheric pressure outside the reference passage.   The leak inspection apparatus according to claim 12, wherein the atmospheric pressure sensor measures an atmospheric pressure in the reference passage opened to the atmosphere through the pump in a stopped state.   The leak inspection apparatus according to claim 14, wherein the absolute pressure sensor also serves as the atmospheric pressure sensor. Comprising an opening control means for opening or blocking the evaporation system side of the reference hole with respect to the atmosphere;
In the state where the evaporation system side of the reference hole is opened to the atmosphere by the opening control means, the pressure loss at the time of opening generated in the reference hole by the inspection operation is equal to the cutoff pressure of the pump,
The first detection means detects the pressure loss during opening as the combined pressure loss,
The leak inspection apparatus according to claim 1, wherein the second detection unit detects a pressure difference between both sides of the reference hole as the reference side pressure loss.   The first detection means has a differential pressure sensor for measuring a difference between the pressure on the evaporation system side of the reference hole opened to the atmosphere by the opening control means and the pressure on the pump side of the reference hole. The leak inspection apparatus according to claim 16.   The second detection means is the differential pressure sensor common to the first detection means, the pressure on the evaporation system side of the reference hole blocked from the atmosphere by the opening control means, and the reference hole The leak inspection apparatus according to claim 17, further comprising: the differential pressure sensor that measures a difference between the pressure on the pump side.

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