JP2012251498A - Leak detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow leak detection of a fuel tank to be performed early after an internal combustion engine is stopped, without a pressure reducing pump provided for each of a plurality of fuel tanks, and without fuel vapor discharged.SOLUTION: After fuel is moved between airtight fuel tanks by a fuel pump, a fuel communication passage between the fuel tanks is opened, so that the fuel is returned through the fuel communication passage by differential pressure between the fuel tanks. Fuel movement quantity Vfy when the fuel is returned (YES at S154-YES at S162) is calculated (S164 and S166). The fuel movement quantity Vfy is compared (S168) with reference fuel movement quantity Vfx calculated based on fuel temperature Tf (S158). When being Vfy≥Vfx, leak is not present (S170), and when being Vfy<Vfx, leak is present (S172). In this leak detection processing, two fuel tanks are airtight with respect to the outside, so that the fuel vapor is not discharged to the outside when the leak is detected, thus, the problem is achieved.

Description

  The present invention relates to a leak detection device in a fuel storage mechanism that stores a fuel to be supplied to an internal combustion engine by including a plurality of fuel storage portions communicated by a fuel communication path.

  There is known an internal combustion engine provided with a plurality of fuel tanks as fuel storage parts, or an internal combustion engine provided with a plurality of fuel storage parts in one fuel tank (see, for example, Patent Document 1).

  There is known an apparatus that detects the presence or absence of a hole in a fuel tank, which is a fuel storage part of an internal combustion engine, based on the purge line pressure (see, for example, Patent Document 2).

Japanese Patent Laying-Open No. 2008-8278 (pages 6-8, FIGS. 1-5) JP-A-2006-177199 (pages 4-6, FIGS. 1-4)

  It is conceivable to perform leak detection as shown in Patent Document 2 for a fuel storage mechanism that stores fuel to be supplied to the internal combustion engine by providing a plurality of fuel storage parts as in Patent Document 1. However, the technique of Patent Document 2 is due to a natural drop in fuel temperature when the internal combustion engine is stopped, and the presence or absence of leakage cannot be detected immediately after the internal combustion engine is stopped, requiring a long internal combustion engine stop time. For this reason, in a hybrid vehicle or the like that intermittently drives or stops the internal combustion engine, even if the internal combustion engine stops, the chance may not be utilized.

  In order to detect leaks at an early stage after the internal combustion engine stops without waiting for the natural decrease in the fuel temperature, a separate decompression pump is provided in each of the fuel storage units to immediately depressurize each fuel storage unit when the internal combustion engine is stopped. It is possible. However, it is necessary to provide a plurality of decompression pumps corresponding to the number of fuel reservoirs, and driving of these decompression pumps causes fuel vapor to be discharged from the fuel reservoir to the outside when a leak is detected. It is not realistic because of the processing problem.

  The present invention provides an internal combustion engine for detecting a leak in a fuel storage section without providing a pressure reducing pump for each fuel storage section and discharging fuel vapor to a plurality of fuel storage sections communicated by a fuel communication path. It is intended to be able to do early after the stop.

In the following, means for achieving the above-mentioned purpose, and its operation and effect are described.
The leak detection device according to claim 1 is a leak detection device in a fuel storage mechanism that stores a fuel to be supplied to an internal combustion engine by including a plurality of fuel storage portions communicated by a fuel communication path, A pressure-feed pump that performs fuel movement between the parts, a fuel temperature sensor that detects a fuel temperature, a fuel movement amount detection means that detects a fuel movement amount through the fuel communication path, an on-off valve for the fuel communication path, After the fuel movement is performed by blocking the passages between the plurality of fuel reservoirs and the outside and driving the pressure pump with the on-off valve closed, the pumping pump is stopped and the opening and closing are performed. A leakage detection preliminary processing means for performing valve opening; a fuel temperature detected by the fuel temperature sensor; and a fuel movement amount detection means after the processing by the leak detection preliminary processing means. Based on the detected fuel movement amount, the movement of the fuel, characterized in that a leakage detecting means for detecting a leak in the fuel reservoir was made.

  Prior to the processing of the leak detection means, the leak detection preliminary processing means blocks the passage between the fuel storage section and the outside, and closes the on-off valve to drive the pressure feed pump to drive the fuel between the fuel storage sections. After that, stop driving of the pressure pump and open the on-off valve.

The leak detection means detects the leak state of the fuel storage portion where the fuel has moved, based on the fuel temperature and the amount of fuel movement due to the opening of the on-off valve.
That is, when the leak detection preliminary processing means moves the fuel between the fuel storage portions by the pressure feed pump, the internal pressure decreases in the outflow side fuel storage portion, and the internal pressure increases in the inflow side fuel storage portion. When the on-off valve that has been closed in this state is opened, the fuel returns from the fuel reservoir on the inflow side to the fuel reservoir on the outflow side due to the pressure difference between the fuel reservoirs generated during fuel movement by the pump. become.

The amount of fuel movement when the fuel returns is detected by the fuel movement amount detection means.
However, when there is a leak in one or both of the fuel reservoirs, the pressure difference between the fuel reservoirs due to the leak is smaller than when there is no leak. Therefore, the presence or absence of leakage is reflected in the amount of fuel movement when the fuel returns when the on-off valve is opened.

  Since the pressure difference between the fuel reservoirs is also related to the fuel vapor pressure in the space in the fuel reservoir, the leak detection means detects the leak state of the fuel reservoir based on the fuel movement amount and the fuel temperature. Can do.

  As described above, after the fuel is moved by the pressure feed pump, the on-off valve of the fuel communication path is opened, and the leak state can be detected using the fuel temperature sensor and the fuel movement amount detecting means. Moreover, since only the fuel is moved between the fuel reservoirs and the fuel reservoir is sealed with respect to the outside, no fuel vapor is released to the outside when a leak is detected.

  As a result, the leak detection of the fuel storage portion is detected with respect to the plurality of fuel storage portions communicated by the fuel communication passage without providing a decompression pump for each fuel storage portion and without discharging the fuel vapor. It can be done early after the stop.

  In the leak detection device according to claim 2, in the leak detection device according to claim 1, the pressure feed pump also serves as a fuel pump for supplying fuel to an internal combustion engine, and the fuel discharge side of the pressure feed pump has the A fuel movement path for executing fuel movement and an internal combustion engine supply path for supplying fuel to the internal combustion engine are connected via a switching valve, and the leak detection preliminary processing means is provided when the internal combustion engine is stopped. It functions, and when the fuel moves, the switching valve is switched, and the fuel discharge side of the pressure feed pump is used as the fuel movement path.

  By using the fuel pump as the pressure pump while the internal combustion engine is stopped, it is not necessary to provide a separate pressure pump for detecting the leak. That is, only by providing the fuel movement path and the switching valve, the fuel can be moved between the fuel reservoirs, and the configuration is simplified.

  The leak detection device according to claim 3, wherein the leak detection means is a fuel detected by the fuel movement amount detection means after processing by the leak detection preliminary processing means. A leak state is detected by comparing the amount of movement with a reference fuel movement amount set based on the fuel temperature detected by the fuel temperature sensor.

  The detection of the leak state by the leak detection means is, for example, to compare the fuel movement amount detected by the fuel movement amount detection means with the reference fuel movement amount set based on the fuel temperature detected by the fuel temperature sensor. It can be realized by the method.

  According to a fourth aspect of the present invention, there is provided the leak detection device according to the third aspect, wherein the leak detection means detects that there is a leak abnormality when the fuel movement amount is smaller than the reference fuel movement amount. Features.

  When the fuel returns due to the pressure difference between the fuel reservoirs generated by driving the pressure feed pump, the amount of fuel movement increases as the pressure difference increases. That is, the amount of fuel movement increases when there is no leak.

Conversely, the smaller the pressure difference, the smaller the amount of fuel movement. That is, when there is a leak, the amount of fuel movement becomes small.
Therefore, the leak detection means can detect a leak abnormality when the fuel movement amount is smaller than the reference fuel movement amount set based on the fuel temperature.

  In the leak detection device according to claim 5, in the leak detection device according to any one of claims 1 to 4, the fuel temperature sensor is any one of the fuel storage portions to which the fuel is moved. The fuel temperature is detected.

  Usually, there is no great difference in the fuel temperature between the fuel reservoirs, and the temperature is almost similar in any fuel reservoir. Therefore, the fuel temperature sensor for detecting the fuel temperature may be provided in any one fuel storage unit. For this reason, it is not necessary to provide a plurality of fuel temperature sensors, and the number of parts can be reduced.

  The leak detection device according to claim 6, wherein the fuel movement amount detection means is any one of the fuel storage portions in which the fuel is moved. One fuel level is detected.

  In the fuel storage part to be moved, the fuel level is lowered in the fuel storage part on the fuel outflow side corresponding to the increase in the fuel level in the fuel storage part on the fuel inflow side.

  Therefore, the same amount of fuel movement can be detected regardless of the fuel level detected in any fuel reservoir. Therefore, the fuel movement amount detection means for detecting the fuel movement amount may be provided in any one fuel storage section. Therefore, it is not necessary to provide a plurality of fuel movement amount detection means, and the number of parts can be reduced.

  The leak detection device according to claim 7, wherein the internal pressure sensor detects the internal pressure of any one of the fuel storage portions to which the fuel is moved in the leak detection device according to any one of claims 1 to 6. The leak detection means includes a fuel temperature detected by the fuel temperature sensor, a fuel movement amount detected by the fuel movement amount detection means after processing by the leak detection preliminary processing means, and the leak detection preliminary A leak state is detected for each of the fuel storage portions to which fuel has been moved based on the internal pressure detected by the internal pressure sensor immediately before the opening / closing valve is opened by the processing means.

  In the processing of the leak detection preliminary processing means, immediately before the opening / closing valve is opened, the internal pressure rises in the fuel storage portion on the side where the fuel flows in by the pressure feed pump, and the internal pressure decreases in the fuel storage portion on the side where the fuel flows out. However, such a change in internal pressure does not occur sufficiently in the fuel storage portion on the side where the leak exists.

Therefore, by adding the determination whether the change of the internal pressure is sufficient or not to the detection based on the fuel temperature and the fuel movement amount described above, it is possible to distinguish the fuel storage portion and detect the leak state.
The leak detection device according to claim 8, wherein the leak detection means includes the fuel temperature detected by the fuel temperature sensor and the processing after the leak detection preliminary processing means. Based on the amount of fuel movement detected by the fuel movement amount detection means, a leak state of the fuel storage section where the fuel has been moved is detected, and if this leak state is a leak abnormality, the leak detection preliminary processing means An individual leak state of the fuel reservoir is detected based on an internal pressure detected by the internal pressure sensor immediately before the opening of the on-off valve.

  In particular, when it is determined that there is a leak abnormality based on the fuel temperature and the amount of fuel movement described above, the leak state can be detected by distinguishing the fuel storage portion based on the internal pressure immediately before the opening / closing valve opens.

1 is a schematic diagram of an internal combustion engine and a fuel supply system thereof according to Embodiment 1. FIG. 6 is a flowchart of leak detection preliminary processing executed by the ECU according to the first embodiment. 3 is a flowchart of a leak detection process executed by the ECU according to the first embodiment. The graph which shows the map which calculates | requires reference | standard fuel movement amount Vfx from fuel temperature Tf. 4 is a timing chart showing a processing example of the first embodiment. Schematic of the internal combustion engine of Embodiment 2 and its fuel supply system. 7 is a flowchart of a leak fuel tank determination process executed by the ECU according to the second embodiment. Schematic which shows the other structural example of a fuel tank.

[Embodiment 1]
<Structure> FIG. 1 shows an internal combustion engine 2 and its fuel supply system 4 to which the above-described invention is applied. The internal combustion engine 2 may be mounted on the vehicle alone as a vehicle drive source, or may be mounted on the vehicle together with the electric motor in a hybrid vehicle or a plug-in hybrid vehicle.

  A fuel injection valve 8 is disposed in each intake port 6 of the plurality of cylinders provided in the internal combustion engine 2. In these fuel injection valves 8, fuels FL 1 and FL 2 stored in two fuel tanks 12 and 14 (corresponding to a plurality of fuel storage portions) of the fuel storage mechanism 10 are supplied to the internal combustion engine by a fuel pump 16. It is pumped through path 18. By the fuel injection control, fuel is injected from the fuel injection valve 8 during intake at a predetermined timing, and is sucked into each cylinder and burned. As a result, the internal combustion engine 2 is driven.

  A fuel temperature sensor 20 is disposed in the main fuel tank 12 of the two fuel tanks 12 and 14, and detects the temperature in the upper space 12a as the fuel temperature Tf. A fuel temperature sensor is not arranged in the sub fuel tank 14. However, since the temperature in the upper space 14a of the sub fuel tank 14 is in a temperature state approximately similar to that of the upper space 12a of the main fuel tank 12, the fuel temperature Tf detected by the fuel temperature sensor 20 is the temperature of the sub fuel tank 14. It also corresponds to the temperature in the upper space 14a.

  Further, a fuel sender gauge 24 for detecting the fuel level SGL in the main fuel tank 12 by the float 24a is provided in the main fuel tank 12. The sub fuel tank 14 is not provided with a fuel sender gauge, but is usually at the same level as the fuel liquid level SGL on the main fuel tank 12 side.

  Refueling is performed from a fuel inlet pipe 28 provided in the sub fuel tank 14. The sub fuel tank 14 is connected to the main fuel tank 12, which is another fuel tank, by a fuel communication path 30 on the lower side thereof. An open / close valve 32 as an electromagnetic valve is provided in the middle of the fuel communication path 30.

  The upper space 12 a of the main fuel tank 12 is connected to a canister 36 by an evaporated fuel passage 34. The evaporative fuel passage 34 is provided with an ORVR valve (Onboard referencing vapor recovery valve) 34 a and a COV (Cut off valve) 34 b at the opening inside the main fuel tank 12.

  Further, the evaporative fuel passage 34 is provided with a block valve unit 35 including a block valve 35 a and a relief valve 35 b between the main fuel tank 12 and the canister 36. The block valve 35a is an electromagnetic valve that can be switched between an open state and a closed state. When the block valve 35a is opened, the upper space 12a of the main fuel tank 12 and the canister 36 communicate with each other through the evaporated fuel passage 34. To do. Thus, the fuel vapor generated in the upper space 12a of the main fuel tank 12 can be discharged to the canister 36 side. When the blocking valve 35a is closed, the evaporated fuel passage 34 is blocked, and the fuel vapor generated in the upper space 12a of the main fuel tank 12 cannot be discharged to the canister 36 side. That is, the inside of the main fuel tank 12 is sealed independently of the canister 36 and is in an airtight state. The relief valve 35b is opened when the difference between the pressure in the evaporated fuel passage 34 on the main fuel tank 12 side and the pressure in the evaporated fuel passage 34 on the canister 36 side is excessive, and the excessive differential pressure is eliminated. It is something to be made.

  The canister 36 includes an adsorbent such as activated carbon that adsorbs fuel therein, and adsorbs fuel vapor discharged from the upper space 12a of the main fuel tank 12 through the evaporated fuel passage 34 as described above. An atmospheric passage 38 communicating with the atmospheric side is connected to the canister 36. The air passage 38 is provided with an air filter 38a on the way. Further, the atmosphere passage 38 is provided with an atmosphere release valve 40 as a normally open electromagnetic valve at a position closer to the canister 36 than the air filter 38a.

  With such a configuration, the fuel introduced from the fuel inlet pipe 28 into the sub fuel tank 14 can be supplied to the sub fuel tank 14 by opening the on-off valve 32 and the blocking valve 35a of the fuel communication passage 30 during refueling. And is also stored in the main fuel tank 12 by flowing into the main fuel tank 12 via the fuel communication passage 30.

  The canister 36 is connected to the intake passage 44 of the internal combustion engine 2 by a purge passage 42 at a position downstream of the throttle valve 46. A purge valve 48 as an electromagnetic valve is disposed in the purge passage 42. The purge is executed by opening the purge valve 48 and the air release valve 40.

In the intake passage 44, an air flow meter 54 is provided between the air filter 52 and the throttle valve 46 to detect the intake air amount GA supplied to the internal combustion engine 2.
In addition, an accelerator opening sensor provided on an accelerator pedal operated by a vehicle driver to detect an accelerator opening ACCP, an engine rotation speed sensor for detecting a rotation speed NE of a crankshaft of the internal combustion engine 2, an IGSW (ignition switch), Other sensors and switches are provided to output signals. Examples of other signals include cooling water temperature, intake air temperature, and vehicle speed.

  Detection signals such as the fuel temperature sensor 20 and the fuel sender gauge 24 including the above signals are input to an electronic control unit (hereinafter referred to as an ECU) 60 that is configured with a microcomputer as a center.

Then, based on such signal data and prestored data, the ECU 60 executes arithmetic processing to control the fuel injection valve 8, the throttle valve 46, and the like.
The fuel FL1 in the main fuel tank 12 is supplied to the fuel injection valve 8 via an internal combustion engine supply path 18, and the fuel discharge side of the fuel pump 16 is connected to the internal combustion engine supply path 18 via a switching valve 62. It is connected.

  This switching valve 62 can switch the fuel discharge side of the fuel pump 16 to a branch path 64 as a fuel movement path. This branch path 64 connects the fuel discharge side of the fuel pump 16 to the sub fuel tank 14.

The switching valve 62 normally feeds the fuel FL1 in the main fuel tank 12 discharged from the fuel pump 16 to the fuel injection valve 8 side via the internal combustion engine supply path 18. However, when the ECU 60 executes the processing shown in FIGS. 2 and 3 to be described later as a leak detection device, the ECU 60 switches the switching valve 62 so that the fuel FL1 in the main fuel tank 12 discharged from the fuel pump 16 is changed. Pressure is fed into the sub fuel tank 14 via the branch path 64.
<Operation> Next, the operation of the present embodiment will be described based on the leak detection preliminary processing (FIG. 2) and the leak detection processing (FIG. 3). These processes are executed at regular time intervals. The steps in the flowchart corresponding to the individual processing contents are represented by “S˜”.

  When the leak detection preliminary process (FIG. 2) is started, it is first determined whether or not a leak detection condition is satisfied (S102). Here, the leak detection condition is as shown by the following a and b.

a. The internal combustion engine 2 is stopped.
b. The fuel level SGL detected by the fuel sender gauge 24 provided in the main fuel tank 12 in the state before the fuel pump 16 is driven is within the fuel movement reference range. (This fuel movement reference range indicates a range of the fuel liquid level SGL in which a predetermined amount of fuel movement described later can be appropriately performed.)
In step S102, the logical product of these conditions a and b is set as a leak detection condition.

In addition to this, the following condition c may be added as a logical product.
c. A predetermined time has elapsed since the internal combustion engine 2 was stopped. (This predetermined time is the time until the fuel vapor pressure stabilizes when the heat generation of the internal combustion engine 2 stops and the fuel temperature fluctuations in the fuel tanks 12, 14 become smaller.)
Alternatively, the following condition d may be added to the conditions a and b as a logical product instead of or together with the condition c.

d. The vehicle has stopped running.
If the leak detection condition is not satisfied (NO in S102), the process is exited as it is. Thereafter, if the leak detection condition is not satisfied in the execution cycle of this process (NO in S102), no substantial process is performed in the leak detection preliminary process (FIG. 2).

If the leak detection condition is satisfied (YES in S102), it is next determined whether or not the leak detection preliminary processing is incomplete (S104).
If it is the first determination under the current leak detection condition, it is not completed since the leak detection preliminary process is started (YES in S104). Next, it is provided in the evaporated fuel passage 34 of the main fuel tank 12. The closed block valve 35a is closed (S106). If the blockade valve 35a has already been closed, the process of maintaining the closed state is performed in step S106.

  Next, the on-off valve 32 provided in the fuel communication passage 30 communicating between the main fuel tank 12 and the sub fuel tank 14 is closed (S108). If the on-off valve 32 has already been closed, in step S108, a process for maintaining the closed state is performed.

  Next, the switching valve 62 is switched to set the fuel discharge direction of the fuel pump 16 to the branch path 64 side (S110). That is, the fuel FL 1 in the main fuel tank 12 can be moved into the sub fuel tank 14. If the switching valve 62 has already been switched to a state in which the fuel pump 16 and the branch path 64 are connected, in step S110, the switching state is maintained.

Next, the fuel pump 16 is driven (S112). As a result, the fuel FL1 in the main fuel tank 12 is moved to the sub fuel tank 14 by the fuel pump 16.
Accordingly, the amount of fuel FL2 in the sub fuel tank 14 increases as shown by the broken line in FIG. 1, and the amount of fuel FL1 in the main fuel tank 12 decreases as shown by the broken line in FIG. become.

  When the amount of fuel in each of the fuel tanks 12 and 14 increases or decreases, the passage (evaporated fuel passage 34) between the fuel storage mechanism 10 and the outside (here, the canister 36) is blocked, and the fuel communication passage 30 is also closed. Yes. Accordingly, the upper space 12a of the main fuel tank 12 is expanded by the decrease of the fuel FL1, and the internal pressure thereof gradually decreases. The upper space 14a of the sub fuel tank 14 is compressed by the increase in the fuel FL2, and its internal pressure gradually increases.

  Next, it is determined whether or not a predetermined amount of fuel has been moved by driving the fuel pump 16 (S114). This predetermined amount can be set by the driving time of the fuel pump 16 or the total number of rotations. By moving a predetermined amount of fuel from the main fuel tank 12 to the sub fuel tank 14, the differential pressure in the internal pressure between the main fuel tank 12 and the sub fuel tank 14 can be made sufficient.

Until the predetermined amount of fuel moves (NO in S114), the present process is left as it is.
When the predetermined amount of fuel movement is completed (YES in S114), the fuel movement between the fuel tanks 12 and 14 is stopped by stopping the fuel pump 16 (S116). Then, the on-off valve 32 is opened (S118). As a result, the fuel tank 12 and the fuel tank 14 communicate with each other through the fuel communication passage 30. Thus, the leak detection preliminary process is completed (S120).

Thereafter, even if YES is determined in step S102, the leak detection preliminary process is completed (NO in S104), and the process immediately exits.
Thus, immediately after the completion of the leak detection preliminary processing, a sufficient differential pressure is generated between the main fuel tank 12 and the sub fuel tank 14 between the main fuel tank 12 and the sub fuel tank 14 as described above, and the fuel communication path 30 is opened. The For this reason, the fuel is returned from the sub fuel tank 14 having a high internal pressure to the main fuel tank 12 having a low pressure via the fuel communication passage 30. That is, the fuel is moved in the reverse direction from the sub fuel tank 14 to the main fuel tank 12.

  The leak detection process (FIG. 3) will be described. In this process, it is first determined whether or not a leak detection condition is satisfied (S152). This leak detection condition is as described in step S102 of FIG.

If the leak detection condition is not satisfied (NO in S152), the process is exited as it is.
If the leak detection condition is satisfied (YES in S152), it is next determined whether or not the leak detection preliminary processing is completed (S154). While the leak detection preliminary process is not completed (S120) in the leak detection preliminary process (FIG. 2) (NO in S154), the fuel sender is set as the fuel level SGLx before the next fuel return occurs. The detection value (SGL) of the gauge 24 is stored (S156).

  Based on the current detection value (Tf) of the fuel temperature sensor 20, a reference fuel movement amount Vfx corresponding to the reference time is calculated (S158). This reference time is set to the length of time for determining the opening time of the on-off valve 32 determined in step S162 described later.

  As will be described later, the differential pressure state between the fuel tanks 12 and 14 is determined from the amount of fuel returned from the sub fuel tank 14 to the main fuel tank 12 during this reference time. Therefore, the reference fuel movement amount Vfx corresponding to the reference time changes corresponding to the internal pressure state of each fuel tank 12, 14. Since the internal pressure state depends on the fuel vapor pressure, the reference fuel movement amount Vfx has a value corresponding to the fuel temperature Tf.

In step S158, the reference fuel movement amount Vfx is calculated based on the fuel temperature Tf, for example, using a map or a calculation formula as shown in FIG.
When the reference fuel movement amount Vfx is calculated in step S158, this process is exited. Thereafter, until the leak detection preliminary process is completed (NO in S154), the fuel level SGLx before fuel return (S156) and the reference fuel movement amount Vfx are updated (S158).

  When the leak detection preliminary process is completed (S120) in the leak detection preliminary process (FIG. 2) (YES in S154), the on-off valve is then opened in step S118 of the leak detection preliminary process (FIG. 2). It is determined whether or not the reference time has elapsed since the opening of the valve 32 (S162). This reference time is as described in step S158.

  If the reference time has not elapsed (NO in S162), the present process is exited. Therefore, the process waits until the reference time has elapsed (NO in S162). In this standby state, the state where the fuel is returned from the sub fuel tank 14 to the main fuel tank 12 continues.

  Therefore, as shown in the timing chart of FIG. 5, the fuel movement amount Vfy (returning fuel movement amount) gradually increases as indicated by the solid line until the reference time elapses after the opening / closing valve 32 is opened.

  When the reference time elapses (YES in S162), the current detection value (SGL) of the fuel sender gauge 24 is read as the fuel level SGLy after the elapse of the reference time (S164).

  Next, a fuel movement amount Vfy due to fuel return is calculated from the fuel level level SGLx before fuel return stored in step S156 and the fuel level level SGLy after elapse of the reference time (S166).

  This fuel movement amount Vfy may be simply calculated as the difference between the two fuel liquid level SGLx and SGLy, and is returned from the difference between the two fuel liquid level SGLx and SGLy and the horizontal sectional shape of the main fuel tank 12. The volume of the remaining fuel may be calculated.

Next, the expression 1 is evaluated (S168).
[Formula 1] Fuel movement amount Vfy ≧ reference fuel movement amount Vfx due to fuel return
If Vfy ≧ Vfx (YES in S168), there is no leakage (S170). If Vfy <Vfx (NO in S168), it is determined that there is a leak (leak abnormality) (S172).

After the leak state is detected in step S170 or step S172, the leak detection completion is set (S174), and the process is exited.
If there is no leak in either of the two fuel tanks 12 and 14, the pressure difference between the fuel tanks 12 and 14 is caused by the fuel movement (S112) by the fuel pump 16 in the leak detection preliminary processing (FIG. 2). Is big enough. For this reason, the opening amount of the on-off valve 32 (FIG. 2: S118) continues for the reference time (FIG. 3: YES in S162), so that the return amount Va (≧ Vfx) is sufficient as shown by the solid line in FIG. Amount.

  However, if there is a leak in one or both of the two fuel tanks 12 and 14, the differential pressure between the fuel tanks 12 and 14 is not sufficiently increased even by the fuel movement. For this reason, even if the opening and closing of the on-off valve 32 is continued for a reference time, the return amount Vb (<Vfx) does not become a sufficient amount as shown by the one-dot chain line in FIG.

Therefore, by evaluating the expression 1, it can be determined whether there is a leak or no leak.
<Relationship with Claims> In the configuration described above, the fuel pump 16 (corresponding to the pressure pump), the fuel temperature sensor 20, the fuel sender gauge 24 (corresponding to the fuel movement amount detecting means), the on-off valve 32, and the ECU 60 detect the leak. It corresponds to a device.

The ECU 60 corresponds to leak detection preliminary processing means and leak detection means. The leak detection preliminary process (FIG. 2) executed by the ECU 60 corresponds to the process as the leak detection preliminary process means, and the leak detection process (FIG. 3) corresponds to the process as the leak detection means.
<Effect> (1) In the leak detection preliminary processing (FIG. 2), the passage between the fuel tanks 12, 14 and the outside is blocked, and the on-off valve 32 of the fuel communication passage 30 is closed to drive the fuel pump 16. Thus, the movement of the fuel is executed, and then the drive of the fuel pump 16 is stopped and the opening / closing valve 32 is opened.

  After the opening / closing valve 32 is opened, the leak state of the fuel tanks 12 and 14 is detected based on the fuel temperature Tf and the fuel movement amount Vfy in the leak detection process (FIG. 3). Specifically, the leak state is detected by comparing the fuel movement amount Vfy and a reference fuel movement amount Vfx set based on the fuel temperature Tf.

  If there is no leak in any of the fuel tanks 12 and 14 as described above, the fuel movement amount Vfy due to the return of fuel from the fuel communication passage 30 increases and becomes equal to or greater than the reference fuel movement amount Vfx.

If there is a leak in one or both of the fuel tanks 12, 14, the fuel movement amount Vfy due to fuel return from the fuel communication path 30 becomes small and less than the reference fuel movement amount Vfx.
Since the reference fuel movement amount Vfx is set according to the fuel temperature Tf, the leak state can be accurately determined by reflecting the fuel vapor pressure state in the fuel tanks 12 and 14. That is, it is possible to accurately determine that there is no leak when Formula 1 is satisfied and that there is leak when Formula 1 is not satisfied.

Moreover, since the two fuel tanks 12 and 14 are hermetically sealed to the outside, fuel vapor is not released to the outside when a leak is detected.
As a result, the fuel tanks 12, 14 communicated by the fuel communication passage 30 are not provided for each of the fuel tanks 12, 14, and the fuel tanks 12, 14 are not discharged without discharging the fuel vapor. 14 leak detection can be performed early after the internal combustion engine is stopped.

(2) If only one of the two fuel tanks 12 and 14 is provided for both the fuel temperature sensor 20 and the fuel sender gauge 24, leak detection is possible.
Furthermore, the fuel pump 16 can also be used as a pressure pump only by switching the switching valve 62.

Therefore, the number of parts can be reduced and the internal combustion engine 2 can be reduced in weight and cost.
[Embodiment 2]
<Configuration> As shown in FIG. 6, in the fuel supply system 104 of the present embodiment, an internal pressure sensor 22 is added to the main fuel tank 12. Therefore, the ECU 160 detects the fuel pressure Tf of the main fuel tank 12 as well as the fuel temperature Tf from the fuel temperature sensor 20 and the fuel level SGL from the fuel sender gauge 24. The other configuration is the same as that of the first embodiment. In FIG. 6, the same components as those in FIG. 1 are denoted by the same reference numerals.

In ECU 160, in addition to the leak detection preliminary process (FIG. 2) and the leak detection process (FIG. 3), the leak fuel tank determination process of FIG. 7 is executed.
<Operation> Next, the operation of the present embodiment will be described. The leak detection preliminary process (FIG. 2) and the leak detection process (FIG. 3) are as described in the first embodiment.

The leak fuel tank determination process (FIG. 7) will be described. This process is executed at regular time intervals.
First, it is determined whether or not the fuel pump 16 has been driven in step S112 of the leak detection preliminary processing (FIG. 2) (S202). If the fuel pump 16 has not been driven yet (YES in S202), the process is exited. Accordingly, no substantial processing is performed.

  When step S112 of the leak detection preliminary process (FIG. 2) is executed and the drive of the fuel pump 16 is started (NO in S202), the fuel pump 16 in step S116 of the leak detection preliminary process (FIG. 2) is started. It is determined whether or not it is after the stop (S204).

  If the fuel pump 16 is being driven (NO in S204), the internal pressure Pf of the main fuel tank 12 detected by the internal pressure sensor 22 and the internal pressure of the main fuel tank 12 detected by the fuel temperature sensor 20 are detected. The fuel temperature Tf is stored (S206).

  Thereafter, while the fuel pump 16 is being driven by the leak detection preparatory process (FIG. 2) (NO in S202, NO in S204), the main fuel tank 12 is repeatedly stored in the main fuel tank 12 to repeatedly store the internal pressure Pf and the fuel temperature Tf. The stored values of the internal pressure Pf and the fuel temperature Tf of 12 are periodically updated.

  When step S116 of the leak detection preliminary process (FIG. 2) is executed and the fuel pump 16 is stopped (YES in S204), it is determined whether or not this is the first process after the fuel pump 16 is stopped (S208). Since the process is initially performed, the tank internal pressure reference value Pfx corresponding to the fuel temperature Tf that has been updated and stored until just before is set (S210).

  The tank internal pressure reference value Pfx is a value that indicates the tank internal pressure that has decreased due to a predetermined amount of fuel flowing out of the main fuel tank 12 by driving the fuel pump 16. When the fuel movement is performed in a short time, since the tank internal pressure corresponds to the fuel vapor amount before the fuel movement, it is calculated from a map or a relational expression corresponding to the fuel temperature Tf.

  Thus, after the tank internal pressure reference value Pfx is set (S210) and this processing is exited, in the next execution cycle, it is determined NO in step S202, YES in step S204, and then the first after the fuel pump 16 is stopped. Therefore, it is determined whether or not the leak detection by the leak detection process (FIG. 3) is completed (S212).

  If the leak detection is not completed (NO in S212), the process is exited. Thereafter, until the leak detection is completed, NO is determined in step S202, YES is determined in step S204, NO is determined in step S208, and NO is determined in step S212.

  When the leak detection is completed, that is, when step S174 of the leak detection process (FIG. 3) is executed (YES in S212), it is determined whether or not the leak detection result is a leak (S214).

If there is no leak (NO in S214), it is determined that there is no leak in both the main fuel tank 12 and the sub fuel tank 14 (S216).
If there is a leak (YES in S214), it is next determined whether the stored value of the tank internal pressure Pf is equal to or less than the tank internal pressure reference value Pfx (S218). The stored value of the tank internal pressure Pf is repeatedly updated when the fuel pump 16 is driven, and thus represents the tank internal pressure Pf of the main fuel tank 12 immediately before the fuel pump 16 stops and the on-off valve 32 opens. ing.

  If there is no leak in the main fuel tank 12, the stored value of the tank internal pressure Pf is sufficiently low and is equal to or less than the tank internal pressure reference value Pfx set in step S210. However, if there is a leak in the main fuel tank 12, the stored value of the tank internal pressure Pf is not sufficiently low, and the state in which the tank internal pressure reference value Pfx set in step S210 is exceeded is maintained.

  Therefore, if Pf ≦ Pfx (YES in S218), the main fuel tank 12 has no leak and the main fuel tank 12 has no leak, and the sub fuel tank 12 has no leak. 14 is determined to have a leak (S220).

If Pf> Pfx (NO in S218), since there is a leak in at least the main fuel tank 12, it is determined that the main fuel tank 12 has a leak (S222).
<Relationship with Claims> In the configuration described above, the fuel pump 16 (corresponding to a pressure feed pump), the fuel temperature sensor 20, the internal pressure sensor 22, a fuel sender gauge 24 (corresponding to fuel movement amount detection means), an on-off valve 32, and ECU 160 corresponds to a leak detection device.

The ECU 160 corresponds to leak detection preliminary processing means and leak detection means. The leak detection preliminary process (FIG. 2) executed by the ECU 160 corresponds to the process as the leak detection preliminary process means, and the leak detection process (FIG. 3) and the leak fuel tank determination process (FIG. 7) correspond to the process as the leak detection means. .
<Effect> (1) The effect of the first embodiment occurs. Furthermore, by combining the state of the tank internal pressure Pf detected by the internal pressure sensor 22 disposed only in the main fuel tank 12 and the leak detection result of the leak detection process (FIG. 3), the fuel tanks 12 and 14 are distinguished to leak. Can be detected, particularly as in step S220.

  Similarly to the fuel temperature sensor 20 and the fuel sender gauge 24, the internal pressure sensor 22 need only be provided in one of the two fuel tanks 12 and 14, so that the number of parts can be reduced and the internal combustion engine 2 can be reduced in weight. Can contribute to cost reduction.

[Other embodiments]
In the leak detection process (FIG. 3), after the reference time has elapsed, leak detection is performed by determining whether or not the fuel movement amount Vfy is greater than or equal to the reference fuel movement amount Vfx. Alternatively, the determination may be made based on the length of time that the fuel movement amount Vfy reaches the reference fuel movement amount Vfx. The longest arrival time when there is no leak is defined as the reference arrival time. If the fuel movement amount Vfy reaches the reference fuel movement amount Vfx before the reference arrival time, no leakage is detected. After the reference arrival time, the fuel movement amount Vfy is determined as the reference fuel. If the movement amount Vfx is reached or if the time limit for detection is exceeded, it may be determined that there is a leak.

  The map of FIG. 4 is a map when the amount of fuel movement by the fuel pump is a fixed amount (here, a predetermined amount). When the fuel movement amount by the fuel pump is not constant, a map for obtaining the reference fuel movement amount Vfx from the fuel temperature Tf and the fuel movement amount by the fuel pump is used instead of the map of FIG.

  Alternatively, when the fuel pump is driven so that all the fuel in the main fuel tank is moved to the sub fuel tank in the process where the fuel movement amount by the fuel pump is not constant, the fuel movement amount is replaced by the fuel movement amount. You may use the fuel remaining amount before a pump drive, ie, the fuel level SGL by a fuel sender gauge. That is, it may be configured as a map for obtaining the reference fuel movement amount Vfx from the fuel temperature Tf and the fuel liquid level SGL before fuel movement by the fuel pump.

In the first embodiment, the fuel temperature sensor and the fuel sender gauge may be disposed only in the sub fuel tank. Alternatively, the fuel tanks may be divided into two fuel tanks.
In the second embodiment, the fuel temperature sensor, the fuel sender gauge, and the internal pressure sensor may be disposed only in the sub fuel tank. Alternatively, the fuel tanks may be divided into two fuel tanks.

  A plurality of fuel storage portions of the fuel storage mechanism are not formed as the fuel tanks 12 and 14 separated into a plurality as shown in FIGS. 1 and 6, but inside one fuel tank 112 as shown in FIG. A plurality of fuel storage portions 112a and 112b may be provided by being divided by the partition wall 114.

  DESCRIPTION OF SYMBOLS 2 ... Internal combustion engine, 4 ... Fuel supply system, 6 ... Intake port, 8 ... Fuel injection valve, 10 ... Fuel storage mechanism, 12 ... Main fuel tank, 12a ... Upper space, 14 ... Sub fuel tank, 14a ... Upper space, DESCRIPTION OF SYMBOLS 16 ... Fuel pump, 18 ... Internal combustion engine supply path, 20 ... Fuel temperature sensor, 22 ... Internal pressure sensor, 24 ... Fuel sender gauge, 24a ... Float, 28 ... Fuel inlet pipe, 30 ... Fuel communication path, 32 ... Open / close valve, 34 ... Evaporative fuel passage, 34a ... ORVR valve, 34b ... COV, 35 ... Blocking valve unit, 35a ... Blocking valve, 35b ... Relief valve, 36 ... Canister, 38 ... Air passage, 38a ... Air filter, 40 ... Air release valve , 42 ... purge passage, 44 ... intake passage, 46 ... throttle valve, 48 ... purge valve, 52 ... air filter, 54 ... air flow Meter, 60 ... ECU, 62 ... switching valve, 64 ... branch path, 104 ... fuel supply system, 112: fuel tank, 112a, 112b ... fuel storing section, 114 ... partition wall, 160 ... ECU, FL1, FL2 ... fuel.

Claims (8)

A leak detection device in a fuel storage mechanism that stores fuel to be supplied to an internal combustion engine by including a plurality of fuel storage portions communicated by a fuel communication path,
A pump for performing fuel movement between the fuel reservoirs; and
A fuel temperature sensor for detecting the fuel temperature;
A fuel movement amount detecting means for detecting a fuel movement amount by the fuel communication path;
An on-off valve for the fuel communication path;
After the fuel movement is performed by blocking the passages between the plurality of fuel reservoirs and the outside and driving the pressure pump with the on-off valve closed, the pumping pump is stopped and the opening and closing are performed. Leak detection preliminary processing means for performing valve opening; and
Based on the fuel temperature detected by the fuel temperature sensor and the fuel movement amount detected by the fuel movement amount detection means after the processing by the leak detection preliminary processing means, the fuel storage section where the fuel has been moved Leak detection means for detecting a leak state;
A leak detection apparatus comprising: 2. The leak detection device according to claim 1, wherein the pressure feed pump also serves as a fuel pump that supplies fuel to an internal combustion engine, and a fuel movement path for performing movement of the fuel on a fuel discharge side of the pressure feed pump. And an internal combustion engine supply path for supplying fuel to the internal combustion engine through a switching valve,
The leak detection preliminary processing means functions when the internal combustion engine is stopped, and switches the switching valve when the fuel moves, so that the fuel discharge side of the pressure feed pump serves as the fuel movement path. Leak detection device. 3. The leak detection device according to claim 1, wherein the leak detection means is detected by the fuel movement amount detected by the fuel movement amount detection means after the processing by the leak detection preliminary processing means and the fuel temperature sensor. A leak detection device that detects a leak state by comparing with a reference fuel movement amount set based on a fuel temperature. 4. The leak detection apparatus according to claim 3, wherein the leak detection means detects a leak abnormality when the fuel movement amount is smaller than the reference fuel movement amount. 5. The leak detection device according to claim 1, wherein the fuel temperature sensor is configured to detect a fuel temperature of any one of the fuel storage portions to which the fuel is moved. Leak detection device. The leak detection device according to any one of claims 1 to 4, wherein the fuel movement amount detection means detects a fuel level of any one of the fuel storage portions where the fuel is moved. A leak detection device characterized by the above. The leak detection device according to any one of claims 1 to 6, further comprising an internal pressure sensor that detects an internal pressure of any one of the fuel storage portions where the fuel is moved,
The leak detection means includes a fuel temperature detected by the fuel temperature sensor, a fuel movement amount detected by the fuel movement amount detection means after processing by the leak detection preliminary processing means, and the fuel detection amount by the leak detection preliminary processing means. A leak detection apparatus, wherein a leak state is detected for each of the fuel storage portions to which fuel has been moved based on an internal pressure detected by the internal pressure sensor immediately before the opening / closing valve is opened. 8. The leak detection device according to claim 7, wherein the leak detection means includes a fuel temperature detected by the fuel temperature sensor and a fuel movement detected by the fuel movement amount detection means after processing by the leak detection preliminary processing means. The internal pressure sensor detects a leak state of the fuel storage section where the fuel has been moved on the basis of the amount, and if the leak state is a leak abnormality, immediately before the opening / closing valve is opened by the leak detection preliminary processing means. A leak detection apparatus for detecting an individual leak state of the fuel storage section based on the internal pressure detected by the above.

Images