JP5099285B2 - Fuel supply device - Google Patents

Description

The present invention relates to a fuel supply device, and more particularly to a technique effective for improving the accuracy of fuel supply control and remaining amount display.

  In recent years, development of fuel cell-equipped vehicles using a fuel cell that generates power by an electrochemical reaction between hydrogen gas and oxygen in the air as a power source has been performed. A hydrogen tank mounted on this type of vehicle is provided with a main stop valve that controls whether or not hydrogen gas is supplied to the fuel cell, and a pressure regulating valve that depressurizes the hydrogen gas compressed to a high pressure. The fuel (hydrogen gas) supply control and the remaining amount display of the hydrogen tank are performed based on the tank internal pressure, the outlet pressure of the main stop valve, the piping volume, and the like.

On the other hand, Patent Document 1 discloses a technique for correcting the tank internal pressure of the hydrogen tank with the tank temperature.
JP 2002-89793 A

  By the way, there is a problem that the pressure sensor on the high pressure side (located upstream of the pressure regulating valve), such as a pressure sensor for measuring the tank internal pressure of the hydrogen tank, has poor accuracy.

  Accordingly, an object of the present invention is to improve the accuracy of the value indicated by the first pressure detection means provided upstream of the pressure regulating valve.

The present invention includes a high-pressure fuel tank, a fuel consuming device that consumes fuel supplied from the high-pressure fuel tank, a pipe that communicates the high-pressure fuel tank and the fuel consuming apparatus, and a control provided on the pipe. A pressure valve, and a pressure detection means provided downstream of the pressure control valve, and the pressure detection means when a primary pressure of the pressure control valve becomes equal to or lower than a pressure regulation set value of the pressure regulation valve. The fuel supply device detects the pressure upstream of the pressure regulating valve based on the detected value.
More specifically, second pressure detection means having pressure detection accuracy relatively lower than that of the pressure detection means is provided upstream of the pressure regulation valve, and the primary pressure of the pressure regulation valve is set to regulate the pressure regulation valve. When the pressure is less than or equal to the value, a value obtained by subtracting the differential pressure between the detection value by the pressure detection means and the second detection value by the second pressure detection means from the second detection value is upstream of the pressure regulating valve. it is detected as a pressure.
In this configuration, the pressure detection accuracy is relatively higher than that of the second pressure regulating valve and the second pressure detecting means, which are lower in the pressure regulation set value than the pressure regulating valve, downstream of the pressure detecting means. Third pressure detecting means is provided in this order, and when the primary pressure of the pressure regulating valve and the second pressure regulating valve becomes equal to or lower than the pressure regulation set value of the second pressure regulating valve, the third pressure detecting means Based on the detected value, the pressure upstream of the pressure regulating valve may be detected. In this case, when the primary pressure of the pressure regulating valve and the second pressure regulating valve is equal to or lower than the pressure regulating set value of the second pressure regulating valve, the detected value by the third pressure detecting means and the second pressure You may make it detect what subtracted from the said 2nd detected value the differential pressure | voltage with the 2nd detected value by a detection means as a pressure upstream from the said pressure regulation valve.

According to such a configuration, when the primary pressure of the pressure regulating valve becomes equal to or lower than the pressure regulation value of the pressure regulating valve, the pressure regulating valve is used to detect the pipe pressure that is lower than the upstream side of the pressure regulating valve. Since the upstream pressure is detected, the detection accuracy is improved.

According to the present invention, when the primary pressure of the pressure regulating valve becomes equal to or lower than the pressure regulation value of the pressure regulating valve, the pressure upstream of the pressure regulating valve is detected using a more accurate pressure detecting means. The detection accuracy is improved.

According to the present invention, it is corrected based on the value of the pressure detecting means provided the value of the pressure detecting means provided on the high pressure side to the low pressure side, also regulated by pressure detecting means provided on the high pressure side It becomes possible to accurately detect the pipe pressure upstream of the pressure valve, and the detection accuracy is improved.

  Next, preferred embodiments for carrying out the present invention will be described with reference to the drawings. The embodiment described below is a fuel supply device for a fuel cell system mounted on a moving body such as an electric vehicle. However, the embodiment is only one aspect of the present invention, and the fuel supply device for a stationary fuel cell system is also used. Applicable.

(First embodiment)
FIG. 1 shows a system configuration diagram of a fuel cell system including a fuel supply device according to the first embodiment. As shown in this figure, the fuel cell system includes a fuel cell stack (fuel consuming device) 10 for supplying hydrogen gas as fuel (hereinafter referred to as fuel system 1), and a system 2 for supplying air. , And a system (not shown) for cooling the fuel cell stack 10.

  The fuel cell stack 10 includes a stack structure in which a plurality of cells including a separator having a flow path of hydrogen gas, air, and cooling water and a MEA (Membrane Electrode Assembly) sandwiched between a pair of separators are stacked. Yes.

  A fuel system (fuel supply device) 1 for supplying hydrogen gas to the fuel cell stack 10 includes a plurality (four) of hydrogen tanks (high-pressure fuel tanks) 11 and hydrogen arranged in order from the hydrogen gas supply source. Pressure sensor (first pressure detecting means) for detecting the pipe line pressure between the pipe 1a communicating with the tank 11 and the fuel cell stack 10, the main stop valves SV1 to 4, the main stop valves SV1 to 4 and the pressure regulating valves Reg1 to Reg4. P1-4, pressure regulating valves Reg1-4, pressure regulating valves Reg1-4—pressure sensors (pressure detecting means, second pressure detecting means) P5 for detecting the line pressure between pressure regulating valves Reg5, pressure regulating valve Reg5, pressure regulating valve Reg5- A pressure sensor P6 that detects a line pressure between the pressure regulating valves Reg6, a pressure regulating valve Reg6, a pressure sensor P7 that detects a line pressure between the pressure regulating valves Reg6 and the fuel cell stack 10, and a control unit 20 are provided.

  The hydrogen tank 11 is a high-pressure hydrogen tank. Instead of the high-pressure hydrogen tank, a hydrogen tank using a hydrogen storage alloy, a hydrogen supply mechanism using a reformed gas, a tank for supplying hydrogen from a liquid hydrogen tank, a liquefied gas fuel A storage tank or the like is applicable. In addition, it is preferable that the fuel is a fuel storage means in which the pressure is uniformly loaded in the tank and the remaining amount of fuel can be detected from the outside not by the liquid level but by the pressure in the tank.

  The main stop valves SV1 to SV4 control whether or not hydrogen gas is supplied from each hydrogen tank 11. The pressure regulating valves Reg1 to 4 reduce the internal pressure of the tank to a predetermined high pressure (for example, 3 Mpa), the pressure regulating valve Reg5 reduces the hydrogen gas reduced to the high pressure to a medium pressure (for example, 1 Mpa), and the pressure regulating valve Reg6 The hydrogen gas reduced to the intermediate pressure is reduced to a low pressure (for example, 0.2 MPa).

  The system 2 for supplying air to the fuel cell stack 10 is not shown in FIG. 1, but is an air cleaner that purifies the outside air and takes it into the fuel cell system, and compresses and supplies the taken-in air according to the control of the control unit 20. A compressor that changes the amount of air and air pressure, a humidifier that adds air to the compressed air by exchanging air off-gas and moisture, and the cooling system of the fuel cell stack 10 includes a radiator, A fan and a cooling pump are provided.

  The control unit 20 is a known computer system such as an ECU, and outputs a control signal for determining the driving amount of various auxiliary devices such as a compressor, or from pressure sensors P1 to P7 disposed at various points in the fuel system 1. In addition to functioning as a control means for outputting control signals for controlling the opening and closing of the main stop valves SV1 to SV4 and the pressure regulating valves Reg1 to 6 based on the detection signals of the pressure sensors P1 to P1 by the procedure described later (FIG. 2). It also functions as a correction means for correcting the tank internal pressure (value) detected at 4 with the pipeline pressure (value) detected by the pressure sensors P5 to P7.

  Next, an example of a tank internal pressure correction calculation process performed in the fuel cell system will be described with reference to the flowchart of FIG.

  This process is executed when the primary pressure of the pressure regulating valves Reg1 to Reg4 becomes equal to or lower than the pressure regulation value, at the time of starting and ending the fuel cell system. For example, when the driver turns on the ignition key as in the case of startup, the control unit 20 reads output signals from the pressure sensors P1 to 7, the FC current sensor (not shown), the main stop valves 1 to 4 and the like, and the pressure P5 Then, the pressures P1 to P4 are stored in the memory or the like as the pressures P1_0 to P4_0 (step S1). At this time, the main stop valves SV1 to SV4 are closed.

  In the subsequent step S2, an offset calculation is performed. In this offset calculation process, differential pressure P1_0-P5,..., Differential pressure P4_0− between the pressures P1_0 to 4_0 detected and stored by the pressure sensors P1 to P4 in step S1 and the pressure P5 detected by the pressure sensor P5. P5 is registered in the memory or the like as offsets P1_offset,..., P4_offset.

  In the subsequent step 3, it is determined whether or not it is a timing (state) at which a tank pressure calculation (step S11) described later can be performed based on the signal read in step S1. If the determination result is “NO”, the subsequent processing is skipped, and the process returns to the calling routine of this processing. On the other hand, if the determination result in step S3 is “YES”, the process proceeds to step S5 to perform abnormality determination.

  This abnormality determination is performed with reference to signals from the pressure sensors 1 to 5. More specifically, this process is performed by correcting the pressures P1 to P4 detected by the pressure sensors P1 to P4 using the offsets P1_offset,..., P4_offset obtained by the offset calculation (step S2) described above, thereby The internal pressure is obtained. When the offsets P1_offset,..., P4_offset are larger than a predetermined value, it is determined that an abnormality has occurred in the pressure sensors P1 to P5 (step S5: “NO”). If it is within the range, it is determined that there is no abnormality (step S5: “YES”).

  If the determination result in step S5 is "NO", the process proceeds to step S7, where an abnormal output such as sounding an alarm or displaying a warning lamp is performed, and the process returns to the calling routine of this process. On the other hand, if the determination result in step S5 is “YES”, the process proceeds to step S11, and the tank internal pressure is calculated using the offsets P1_offset,..., P4_offset obtained in step S2.

  That is, the pipeline pressure between the main stop valves SV1 to SV4 to Reg1 to Reg4 is the same as that of the regulating valves Reg1 to 4, such as when the system is started up or when the hydrogen remaining in the pipeline is consumed after the system is stopped. When the pressure is less than or equal to the pressure setting value, the throttles at the pressure regulating valves Reg1 to Reg4 are lost, so the primary side line pressure of the pressure regulating valves Reg1 to Reg4, in other words, the pressures P1 to P4 detected by the pressure sensors P1 to The secondary side pipe pressure of the pressure regulating valves Reg1 to 4, in other words, the pressure P5 detected by the pressure sensor P5 is the same pressure.

  In the present embodiment, as described in the pressure reducing characteristics of the pressure regulating valves Reg1 to Reg5, the primary pressure regulating valve Reg5 is larger than the pressure sensors P1 to P4 disposed in the primary pipes of the pressure regulating valves Reg1 to Reg4. Since the pressure sensor P5 disposed in the side pipe (secondary pipe of the pressure regulating valves Reg1 to 4) is for a lower pressure, the pressure detection accuracy is better. For this reason, if a pressure difference occurs between the pressures P1 to P4 and the pressure P5 at the above timing, the pressure difference between the pressures P1 to P4 is detected by the pressure sensors P1 to P4. This corresponds to an error with respect to the actual tank pressure.

  Therefore, the offsets P1_offset,..., P4_offset corresponding to the error are registered (learned) in advance (step S2), and the offsets P1_offset,..., P4_offset are subtracted from the detected pressures of the pressure sensors P1 to P4. If it is regarded as the internal pressure (step S11), the detection accuracy of the tank internal pressure is improved as compared with the case where the pressure detected by the pressure sensors P1 to P4 is regarded as the tank internal pressure as it is.

  2 may be executed not only at the time of starting and at the end, but also at a predetermined time interval or whenever a specific event occurs.

  As described above, in the present embodiment, the pressures P1 to P4 detected by the pressure sensors P1 to P4 are not regarded as the in-tank pressure of the hydrogen tank 11 as they are, but are adjusted, for example, at the time of system startup or termination. When the primary pressures of the pressure valves Reg1 to Reg4 are equal to or lower than the pressure regulation value, that is, when the primary pressure and the secondary pressure of the pressure regulation valves Reg1 to Reg4 are equal, these primary pressure and secondary pressure. Is detected by the pressure sensors P1 to P5, and the differential pressure between the two is stored as an offset P1_offset,..., P4_offset, and the pressures P1 to P4 detected by the pressure sensors P1 to P4 are corrected using the offsets P1_offset,. This is regarded as the tank internal pressure of the hydrogen tank 11.

  In other words, the in-tank pressure of the hydrogen tank 11 is obtained by correcting the detection pressures P1 to P4 of the pressure sensors P1 to P4, which are inferior in detection accuracy at low pressure, with the detection pressure P5 of the pressure sensor P5 having better detection accuracy. Therefore, the detection accuracy is improved, and the accuracy of fuel supply control and tank remaining amount display is also improved.

  In particular, when the hydrogen consumption progresses and the tank internal pressure decreases to the vicinity of the gas shortage, the accuracy of detection of the pressure in the tank by the pressure sensors P1 to P4 decreases significantly. However, in this embodiment, since the pressure accuracy in the vicinity of the gas shortage is particularly improved, the margin can be reduced and the cruising distance can be extended.

(Second Embodiment)
Note that the offsets P1_offset,..., P4_offset in the above embodiment are not only at the time of starting or ending, but also when the primary pressure of the pressure regulating valves Reg1 to Reg4 is equal to or lower than the pressure regulating value, that is, the pressure regulating valves Reg1 to Reg4. If the primary pressure and the secondary pressure are the same pressure, they can be updated (learned) at any time. For example, in FIG. 1, when the detected pressure P5 of the pressure sensor P5 is equal to or lower than the pressure regulation value of the pressure regulating valve Reg5, the pressure sensor (second pressure sensing) disposed on the secondary side (downstream side) of the pressure regulating valve Reg5. Means) By using the detected pressure P6 of P6, “offset P1_offset,..., P4_offset = Pn_0−P6”.

  In such a case, since the offset P1_offset,..., P4_offset is obtained using the detection result of the low pressure sensor P6, the accuracy is improved and the pressure detection accuracy of the hydrogen tank 11 is further improved. To do. Similarly, when the detected pressure P6 of the pressure sensor P6 is equal to or less than the pressure regulation value of the pressure regulating valve Reg6, the pressure sensor (second pressure detecting means) P7 disposed on the secondary side (downstream side) of the pressure regulating valve Reg6. If the detected pressure P7 is used as “offset P1_offset,..., P4_offset = Pn_0−P7”, the pressure detection accuracy of the hydrogen tank 11 is further improved.

  Further, the present invention is not limited to the application to the fuel supply apparatus provided with the same number of pressure regulating valves Reg1 to Regulate the plurality of hydrogen tanks 11 as in the above embodiment (FIG. 1). For example, as shown in FIG. 3, the present invention can be applied to a fuel supply apparatus including a single pressure regulating valve Reg <b> 1, Reg <b> 3 for a plurality (two in the figure) of hydrogen tanks 11. Furthermore, as long as the 1st pressure detection means of this invention is arrange | positioned upstream of a pressure regulation valve, of course, it is not limited to what detects the tank internal pressure of a high pressure fuel tank.

( Reference example )
Next , a reference example will be described with reference to FIGS.

The main structural difference between the present reference example and the first and second embodiments is that the fuel supply device according to the present reference example has the pressure sensors P1 to P4 in FIGS. 1 and 3 as shown in FIG. The pressure regulating valves Reg1 to Reg4 are configured by a poppet type diaphragm pressure regulating valve 40 as shown in FIG. 5, for example. The other components in FIG. 4 can adopt the same configuration as that in FIG. 1, and therefore, in the following description, the same reference numerals are given and the description thereof is omitted.

  The pressure regulating valve 40 has an outer shell constituted by a housing 51, and a primary inflow port 52 and a secondary outflow port 53 are formed in the housing 51. The internal space of the housing 51 is partitioned up and down by a diaphragm 56 to which a valve body 55 is connected, and the space above these is configured as a flow path through which hydrogen gas can flow from the primary side to the secondary side. The lower space is configured as a back pressure chamber 57 opened to atmospheric pressure.

  The back pressure chamber 57 is provided with a pressure adjusting spring 58 that urges the valve body 55 in the valve opening direction (upward in FIG. 4). The pressure adjusting spring 58 has a predetermined property such as a spring constant. The valve body 55 is provided with a poppet 60 through a stem 59, and the side surface of the poppet 60 is configured to be detachable from a valve seat 61 provided in the housing 51.

  In a state where the valve body 55 in which the poppet 60 is separated from the valve seat 61 is opened, the flow path between the primary side and the secondary side is in communication and the flow of hydrogen gas to the secondary side is allowed. On the other hand, in a state where the valve element 55 in which the poppet 60 contacts the valve seat 61 is closed, the flow path between the primary side and the secondary side is blocked, and the flow of hydrogen gas to the secondary side is blocked. .

  Between the upper surface of the poppet 60 and the housing 51, a pressure regulating spring 62 that urges the valve body 55 in the valve closing direction (downward in FIG. 4) via the poppet 60 is disposed. The pressure adjusting spring 62 is disposed coaxially with the pressure adjusting spring 58 and the stem 59, and the properties such as the spring constant are set to a predetermined value like the pressure adjusting spring 58. A pressure adjustment value on the secondary side is set from the pressure adjusting spring 62 and the pressure adjusting spring 58.

  The pressure regulating valve 40 configured as described above has a secondary pressure of hydrogen gas that acts on the valve body 55 and the diaphragm 56 from the upper surface side, an urging force of the pressure regulating spring 62, an atmospheric pressure that acts from the lower surface side, and The secondary pressure of the hydrogen gas is adjusted by adjusting the opening degree of the valve body 55 (the position of the poppet 60) according to the urging force of the pressure adjusting spring 58.

  In the fuel cell system in which such a pressure regulating valve 40 is disposed immediately below the hydrogen tank 11, an abnormality (for example, fuel leakage) in the hydrogen tank 11 provided on the upstream side of the pressure regulating valve 40 is detected. It is possible to detect based on the detected pressure P5 of the pressure sensor P5 provided on the downstream side of the pressure valve 40.

  For example, when a problem or the like occurs in the hydrogen tank 11 and the tank internal pressure becomes lower than the secondary side pressure regulation value of the pressure regulating valve 40, the lower surface side of the diaphragm 56 (back pressure chamber 57 side) in the pressure regulating valve 40. The biasing force from the atmospheric pressure and the pressure adjusting spring 58 acting on the pressure increases as compared with the secondary pressure of the hydrogen gas acting on the upper surface side and the biasing force from the pressure regulating spring 62.

  Then, since the poppet 60 is separated from the valve seat 61 and the valve body 55 is greatly opened, the pipe pressure drop rate (pressure drop amount per predetermined time) in the pipe 1a on the downstream side of the pressure regulating valve 40 increases. When the pressure drop rate is equal to or greater than a predetermined threshold, the control unit 20 determines that an abnormality has occurred in the hydrogen tank 11 (detects an abnormality), closes the main stop valves SV1 to SV4, and closes the hydrogen tank 11. And communication with the fuel cell stack 10 are blocked.

Thereby, useless fuel discharge from the hydrogen tank 11 can be suppressed. Further, when the secondary pressure of the pressure regulating valve 40 is higher than the atmospheric pressure, the gas release from the secondary side can be suppressed. Furthermore, according to this reference example , based on the detection result of the pressure sensor P5 disposed on the downstream side of the pressure regulating valve 40, the abnormality of the hydrogen tank 11 can be detected to shut off the main stop valves SV1 to SV4. Therefore, the pressure sensors P1 to P4 in the hydrogen tank 11 can be made unnecessary as in the first and second embodiments.

It is a block diagram which shows the system configuration | structure of the fuel cell system provided with the fuel supply apparatus which concerns on the 1st Embodiment of this invention. It is a flowchart explaining the correction calculation process of the pressure in a tank at the time of system starting of the embodiment. It is a block diagram which shows the system configuration | structure of the fuel cell system provided with the fuel supply apparatus which concerns on the 2nd Embodiment of this invention. It is a block diagram which shows the system configuration | structure of the fuel cell system provided with the fuel supply apparatus which concerns on a reference example . It is sectional drawing which shows one structural example of the pressure regulation valve provided in the fuel supply apparatus which concerns on the reference example .

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1a ... Piping, 10 ... Fuel cell stack (fuel consumption apparatus), 11 ... Hydrogen tank (high pressure fuel tank), P1-P4 ... Pressure sensor (first pressure detection means), P5-P7 ... Pressure sensor (pressure detection means, Second pressure detecting means), Reg1 to Reg6, pressure regulating valve

Claims (2)

A high-pressure fuel tank, a fuel consuming device that consumes fuel supplied from the high-pressure fuel tank, a pipe communicating the high-pressure fuel tank and the fuel consuming apparatus, a pressure regulating valve provided on the pipe, A pressure detecting means provided downstream of the piping from the pressure regulating valve; and a second pressure detecting means having a pressure detection accuracy relatively lower than the pressure detecting means upstream of the pressure regulating valve;
When the primary pressure of the pressure regulating valve becomes equal to or lower than the pressure regulation set value of the pressure regulating valve, the differential pressure between the detected value by the pressure detecting means and the second detected value by the second pressure detecting means is detected by the second detection. A fuel supply device that detects a value subtracted from a value as a pressure upstream of the pressure regulating valve.   A second pressure regulating valve having a pressure regulation setting value lower than that of the pressure regulating valve and a third pressure having a pressure detection accuracy relatively higher than that of the second pressure detecting means downstream of the pressure sensing means from the piping. Detection means are provided in this order,
  When the primary pressure of the pressure regulating valve and the second pressure regulating valve is equal to or lower than the pressure regulating set value of the second pressure regulating valve, the detected value by the third pressure detecting means and the second pressure detecting means 2. The fuel supply device according to claim 1, wherein a pressure obtained by subtracting a differential pressure from a second detection value from the second detection value is detected as a pressure upstream of the pressure regulating valve.