JP5375652B2 - Fuel supply device - Google Patents

Description

  The present invention relates to a fuel supply device for an internal combustion engine, and more particularly to a fuel supply device for supplying a dual fuel using a plurality of liquid fuels to the internal combustion engine.

In recent years, liquid fuels used in internal combustion engines have been diversified from the viewpoints of environmental protection and resource protection (see Patent Document 1 for a dual fuel internal combustion engine). For example, ethanol and liquid synthetic fuel (XTL) are used in addition to conventional gasoline and light oil. When a plurality of types of fuel are used in accordance with such fuel diversification, the internal combustion engine needs to include a plurality of independent fuel supply systems for the plurality of types of fuel.
However, in order to supply a plurality of types of fuel from the fuel tanks to the fuel injection unit, a plurality of feed pumps corresponding to the number of fuel tanks, that is, the types of fuels, are required. As a result, there is a problem that the number of parts is increased and the structure is complicated.

JP-A-8-284704

  Accordingly, an object of the present invention is to provide a fuel supply device that supplies a plurality of types of liquid fuel individually to a fuel injection section with a simple structure without increasing the number of parts.

In the first aspect of the present invention, the pressurized air generating section and the plurality of fuel tanks are connected by the pressurized air passage section. The fuel supply controller supplies pressurized air from the pressurized air generator to the plurality of fuel tanks by opening the pressurized air passage. Thus, the fuel tank is pressurized by the supplied air, and the stored fuel is supplied to the fuel injection unit. That is, by supplying pressurized air from a single pressurized air generator to a plurality of fuel tanks, the fuel stored in the fuel tank is pushed out by the pressurized air and supplied to the fuel injector. As a result, no separate pump or the like is required from the fuel tank to the fuel injection unit. Therefore, a plurality of types of liquid fuel can be individually supplied to the fuel injection unit with a simple structure without increasing the number of parts.
In the first aspect of the invention, the leak valve maintains the pressure inside the pressurized air passage and the fuel tank at the set pressure. This set pressure is preset in a predetermined range between the upper limit value and the lower limit value. As a result, the pressure of the fuel supplied from the fuel tank to the fuel injection unit is adjusted within the set pressure range. Therefore, fuel can be stably supplied from the fuel tank to the fuel injection unit.
According to the first aspect of the present invention, the leak valve opens when the fuel tank is refilled. Thereby, the pressure inside the pressurized air passage and the fuel tank is maintained at a pressure lower than the set pressure. The inside of the pressurized air passage and the fuel tank is adjusted to a pressure close to atmospheric pressure, for example, by opening the leak valve. Therefore, when fuel is supplied to the fuel tank, the fuel in the fuel tank does not blow out to the outside. Therefore, safety can be improved.

In the invention according to claim 2, the fuel injection section is provided for each type of fuel. That is, the plurality of types of fuel stored in the plurality of fuel tanks are supplied to the fuel injection unit without being mixed. Therefore, different types of fuel can be supplied to the fuel injection unit in accordance with the operating state of the internal combustion engine.
According to a third aspect of the present invention, the passage opening / closing valve closes the pressurized air passage when the internal combustion engine stops operating. Thus, when the internal combustion engine is stopped, the flow of air from the fuel tank to the pressurized air generation unit via the pressurized air passage unit is blocked by the passage opening / closing valve. Therefore, the inflow of air containing fuel from the pressurized fuel tank to the pressurized air generating unit side is prevented. Therefore, it is possible to reduce deterioration of the pressurized air generation unit and performance degradation.

The schematic diagram which shows the structure of the fuel supply apparatus by one Embodiment of this invention. The schematic diagram which shows the internal combustion engine to which the fuel supply apparatus by one Embodiment of this invention is applied. The block diagram which shows the structure of the fuel supply apparatus by one Embodiment of this invention. Schematic diagram showing the flow of operation of the fuel supply device according to an embodiment of the present invention when starting the internal combustion engine and operating the internal combustion engine Schematic which shows the flow of operation | movement at the time of an internal combustion engine stop of the fuel supply apparatus by one Embodiment of this invention.

Hereinafter, a fuel supply device according to an embodiment of the present invention will be described with reference to the drawings.
As shown in FIG. 2, the fuel supply device 10 supplies different types of liquid fuel to the internal combustion engine 11. In the case of this embodiment, the fuel supply device 10 supplies two types of fuel to the internal combustion engine 11. As shown in FIGS. 1 and 3, the fuel supply device 10 includes a fuel tank 12, a fuel tank 13, a fuel injection unit 14, a fuel injection unit 15, a pressurized air generation unit 16, a pressurized air passage unit 17, a passage opening / closing valve. 18, a fuel supply control unit 19 and a leak valve 21 are provided. The fuel tank 12 and the fuel tank 13 store different types of liquid fuel. The fuel stored in the fuel tank 12 and the fuel tank 13 is selected in any combination depending on the type of the internal combustion engine 11, such as gasoline, light oil, alcohols, ethers, and XTL. In the present embodiment, a diesel engine will be described as an example of the internal combustion engine 11, and light oil and alcohol will be described as examples of liquid fuel. Therefore, the fuel tank 12 stores light oil, and the fuel tank 13 stores alcohol. The alcohol is not limited to methanol and ethanol, and can be arbitrarily selected regardless of the carbon number and structure, such as propanol, butanol or isopropyl alcohol.

  As shown in FIG. 2, the internal combustion engine 11 includes a cylinder block 22, a cylinder head 23, a piston 24, an intake valve 25, an exhaust valve 26, an intake pipe portion 27, an exhaust pipe portion 28, and the like. The piston 24 reciprocates in the axial direction inside a cylinder 29 formed by the cylinder block 22. A combustion chamber 31 is formed between the inner wall of the cylinder block 22, the inner wall of the cylinder head 23, and the end face of the piston 24. An intake pipe portion 27 and an exhaust pipe portion 28 are connected to the combustion chamber 31. The intake pipe portion 27 forms an intake passage 32 through which intake air flows. The exhaust pipe portion 28 forms an exhaust passage 33 through which exhaust flows. The intake valve 25 opens and closes between the intake passage 32 formed by the intake pipe portion 27 and the combustion chamber 31. The exhaust valve 26 opens and closes between the exhaust passage 33 formed by the exhaust pipe portion 28 and the combustion chamber 31.

  The fuel injection unit 14 injects the fuel stored in the fuel tank 12 into the internal combustion engine 11, and the fuel injection unit 15 injects the fuel stored in the fuel tank 13 into the internal combustion engine 11. Specifically, the fuel injection unit 14 shown in FIGS. 1 and 3 includes the injector 35 shown in FIG. 2, a fuel pipe unit and a fuel pressurizing unit (not shown). As shown in FIG. 2, the injector 35 penetrates the cylinder head 23 and the tip is exposed to the combustion chamber 31. A fuel pipe (not shown) connects the fuel tank 12 and the injector 35 via a fuel pressurizing unit. The fuel pressurizing unit (not shown) has a fuel filter, a fuel injection pump, a common rail, and the like (not shown). The fuel discharged from the fuel tank 12 is pressurized by the fuel injection pump and then stored in the common rail. The high-pressure fuel stored in the common rail is directly injected into the combustion chamber 31 from an injection hole (not shown) formed at the tip of the injector 35.

  On the other hand, the fuel injection unit 15 injects the fuel stored in the fuel tank 13 into the internal combustion engine 11. Specifically, the fuel injection section 15 shown in FIGS. 1 and 3 includes the injector 36 shown in FIG. 2 and a fuel pipe section (not shown). The injector 36 penetrates the intake pipe portion 27 and has a tip exposed to the intake passage 32. A fuel pipe (not shown) connects between the fuel tank 13 and the injector 36. The fuel injection unit 15 includes a fuel filter (not shown). The fuel discharged from the fuel tank 13 is injected into the intake air flowing through the intake passage 32 from an injection hole (not shown) formed at the tip of the injector 36.

  The light oil stored in the fuel tank 12 is directly injected from the injector 35 into the combustion chamber 31. Therefore, the light oil is pressurized by the fuel injection pump and stored in the common rail. On the other hand, the alcohol stored in the fuel tank 13 is higher in volatility than light oil. Therefore, the alcohol is injected from the injector 36 and mixed with the intake air flowing through the intake passage 32. Thereby, alcohol is supplied from the fuel tank 13 to the injector 36.

  1 and 3 includes, for example, a compressor, and supplies pressurized air to the fuel tank 12 and the fuel tank 13. This compressor can be shared with other systems when the compressor is provided in another system such as a vehicle brake system. The pressurized air generation unit 16 generates air having a pressure higher than atmospheric pressure. Hereinafter, the pressurized air generated by the pressurized air generation unit 16 is referred to as “pressurized air”.

  The pressurized air passage portion 17 connects the pressurized air generating portion 16 with the fuel tank 12 and the fuel tank 13. In the case of the present embodiment, one end of the pressurized air passage portion 17 is connected to the pressurized air generating portion 16, branches in the middle, and the other end is connected to the fuel tank 12 and the fuel tank 13, respectively. ing. The pressurized air passage portion 17 forms a pressurized air passage 40 through which the pressurized air generated by the pressurized air generating portion 16 flows. The pressurized air passage 40 branches into a first passage 41 connected to the fuel tank 12 and a second passage 42 connected to the fuel tank 13. The passage opening / closing valve 18 opens and closes the pressurized air passage 40. Specifically, the passage opening / closing valve 18 is provided on the air outlet side of the pressurized air generation unit 16 and opens and closes the pressurized air passage 40. The fuel supply controller 19 shown in FIG. 3 controls the opening / closing of the passage opening / closing valve 18. The passage opening / closing valve 18 is opened and closed by an electrical signal, for example. Thus, the passage opening / closing valve 18 that opens and closes by an electrical signal opens and closes the pressurized air passage 40 by an electrical signal output from the fuel supply control unit 19.

  When the fuel supply control unit 19 opens the pressurized air passage 40 by the passage opening / closing valve 18, the pressurized air is supplied to the fuel tank 12 via the pressurized air passage 40 and the first passage 41, and the pressurized air passage It is supplied to the fuel tank 13 via 40 and the second passage 42. By supplying pressurized air to the fuel tank 12 and the fuel tank 13, the pressure inside the fuel tank 12 and the fuel tank 13 increases. Therefore, the light oil stored in the fuel tank 12 and the alcohol stored in the fuel tank 13 are respectively discharged to the fuel injection unit 14 and the fuel injection unit 15 due to an increase in pressure. As a result, the light oil in the fuel tank 12 is supplied to the injector 35 via the fuel pressurizing unit, and the alcohol in the fuel tank 13 is supplied to the injector 36. On the other hand, when the fuel supply control unit 19 closes the pressurized air passage 40 by the passage opening / closing valve 18, the supply of the pressurized air from the pressurized air generation unit 16 to the pressurized air passage 40 is shut off. Further, when the pressurized air passage 40 is closed by the passage opening / closing valve 18, the flow of air from the pressurized air passage 40 to the pressurized air generating unit side is also blocked. Thereby, the passage opening / closing valve 18 prevents the backflow of air from the pressurized air passage 40 to the pressurized air generating unit 16 side.

  The leak valve 21 is provided in the middle of the pressurized air passage 40. In the case of the present embodiment, the leak valve 21 is provided between the passage opening / closing valve 18 and the first passage 41 and the branch portion of the second passage 42 in the pressurized air passage 40. The leak valve 21 is opened and closed by an electrical signal from the fuel supply control unit 19. The leak valve 21 opens to connect the pressurized air passage 40 to the atmosphere. Therefore, when the leak valve 21 is opened, the pressure of the pressurized air in the pressurized air passage 40 decreases. The fuel supply control unit 19 opens and closes the leak valve 21 to maintain the pressures of the pressurized air passage 40, the fuel tank 12, and the fuel tank 13 at a set pressure within a preset range. The leak valve 21 is opened when fuel is supplied to the fuel tank 12 and the fuel tank 13 from the outside. If the fuel tank 12 and the fuel tank 13 are always pressurized with air, the fuel inside the fuel tank 12 is opened when the lid of the fuel filler opening 43 of the fuel tank 12 or the lid of the fuel filler opening 44 of the fuel tank 13 is opened at the time of fuel supply. There is a risk of blowing out. Therefore, the leak valve 21 is opened when fuel is supplied to the fuel tank 12 and the fuel tank 13. Thereby, the pressures of the pressurized air passage 40, the fuel tank 12, and the fuel tank 13 are lower than the above-described set pressure, such as a pressure close to atmospheric pressure. As a result, fuel blowing out from the fuel tank 12 and the fuel tank 13 is avoided.

  The fuel supply apparatus 10 includes a first pressure sensor 46, a second pressure sensor 47, and a control unit 48 in addition to the above-described configuration. The first pressure sensor 46 is provided between the pressurized air generation unit 16 and the passage opening / closing valve 18 in the pressurized air passage 40. The first pressure sensor 46 detects the pressure between the pressurized air generation unit 16 and the passage opening / closing valve 18 and outputs the detected pressure to the control unit 48 as an electrical signal. The second pressure sensor 47 is provided between the passage opening / closing valve 18 and the leak valve 21 in the pressurized air passage 40. The second pressure sensor 47 detects the pressure between the passage opening / closing valve 18 and the leak valve 21 and outputs the detected pressure to the control unit 48 as an electrical signal.

  The control unit 48 is constituted by a microcomputer having a CPU, ROM and RAM (not shown). The control unit 48 may be configured integrally with the fuel supply control unit 19 described above. The control unit 48 may be configured integrally with an ECU (Engine Control Unit). The controller 48 controls the opening / closing of the passage opening / closing valve 18 and the leak valve 21 based on the air pressure detected by the first pressure sensor 46 and the second pressure sensor 47.

Next, the operation of the fuel supply device 10 configured as described above will be described.
(When starting internal combustion engine)
First, the flow of operation when the internal combustion engine 11 to which the fuel supply device 10 is applied will be described with reference to FIG.
Prior to starting the internal combustion engine 11, the fuel supply control unit 19 activates the pressurized air generation unit 16 (S101). In order to start the internal combustion engine 11, it is necessary to supply fuel from the fuel tank 12 and the fuel tank 13 to the fuel injection unit 14 and the fuel injection unit 15. Therefore, the fuel supply control unit 19 generates pressurized air to be supplied to the fuel tank 12 and the fuel tank 13 before the internal combustion engine 11 is started. In addition, when the fuel pressure sufficient to start the internal combustion engine 11 is secured in the fuel injection unit 14 as in a common rail fuel injection system, for example, after the internal combustion engine 11 is started or when the internal combustion engine 11 is started. At the same time, the pressurized air generator 16 may be activated.

  The fuel supply control unit 19 closes the leak valve 21 and activates the pressurized air generation unit 16 (S102), and closes the passage opening / closing valve 18 (S103). When the pressurized air generated by the pressurized air generating unit 16 rises to a sufficient pressure, the fuel supply control unit 19 starts supplying pressurized air to the fuel tank 12 and the fuel tank 13. Therefore, the fuel supply control unit 19 closes the leak valve 21 and the passage opening / closing valve 18 and waits until the pressure of the pressurized air rises in the pressurized air generation unit 16. The activation of the pressurized air generation unit 16 in S101, the closing of the leak valve 21 in S102, and the closing of the passage opening / closing valve 18 in S103 may be performed at the same time without causing a time lag.

  When the leak valve 21 and the passage opening / closing valve 18 are closed, the fuel supply control unit 19 obtains the pressure of the pressurized air passage 40 closer to the pressurized air generation unit 16 than the passage opening / closing valve 18 from the first pressure sensor 46. (S104). That is, the fuel supply control unit 19 monitors the pressure of the pressurized air generated by the pressurized air generation unit 16 activated in S101. Then, the fuel supply control unit 19 determines whether or not the pressure of the pressurized air in the pressurized air passage 40 acquired in S104 has reached a preset lower limit pressure (S105). This lower limit pressure is set in advance as a value for determining whether or not the pressurized air has reached a pressure sufficient to supply the fuel tank 12 and the fuel tank 13. When the pressure of the pressurized air passage 40 detected by the first pressure sensor 46 becomes larger than the lower limit pressure, the air pressure is such that it can be supplied from the pressurized air generator 16 to the fuel tank 12 and the fuel tank 13.

  When determining that the pressure of the pressurized air acquired in S104 has reached the lower limit pressure (S105: Yes), the fuel supply control unit 19 opens the passage opening / closing valve 18 (S106). As a result, the pressurized air generated by the pressurized air generation unit 16 is supplied to the fuel tank 12 and the fuel tank 13 via the pressurized air passage 40. By supplying pressurized air to the fuel tank 12 and the fuel tank 13, the light oil in the fuel tank 12 is supplied from the fuel tank 12 to the fuel injection unit 14, and the alcohol in the fuel tank 13 is supplied from the fuel tank 13 to the fuel injection unit 15. Supplied. On the other hand, if the fuel supply control unit 19 determines that the pressure of the pressurized air acquired in S104 does not reach the lower limit pressure (S105: No), the fuel supply control unit 19 returns to S104 and continues to close the passage opening / closing valve 18.

  When the passage opening / closing valve 18 is opened, the fuel supply control unit 19 acquires the pressure of the pressurized air passage 40 on the fuel tank 12 and fuel tank 13 side from the second pressure sensor 47 with respect to the passage opening / closing valve 18 (S107). That is, the fuel supply control unit 19 monitors the pressure of the pressurized air supplied to the fuel tank 12 and the fuel tank 13. Then, the fuel supply control unit 19 determines whether or not the pressure of the pressurized air in the pressurized air passage 40 acquired in S107 is larger than a preset lower limit value (S108). This set lower limit value is a minimum pressure required for the pressure of the pressurized air in the fuel tank 12 and the fuel tank 13 to be sufficient to supply fuel from the fuel tank 12 and the fuel tank 13. If the pressure of the pressurized air detected by the second pressure sensor 47 is larger than the set lower limit value, the pressurized air of sufficient pressure is supplied from the pressurized air generator 16 to the fuel tank 12 and the fuel tank 13. .

  When the fuel supply control unit 19 determines in S108 that the pressure of the pressurized air is larger than the set lower limit value (S108: Yes), the pressure of the pressurized air in the pressurized air passage 40 acquired in S107 is preset. It is determined whether it is smaller than the set upper limit value (S109). This set upper limit is set as the upper limit of the pressure of the pressurized air supplied to the fuel tank 12 and the fuel tank 13. If the pressure of the pressurized air detected by the second pressure sensor 47 is smaller than the set upper limit value, the pressurized air of sufficient pressure is supplied from the pressurized air generator 16 to the fuel tank 12 and the fuel tank 13. . On the other hand, when the pressure of the pressurized air detected by the second pressure sensor 47 exceeds the set upper limit value, the pressure of the pressurized air supplied to the fuel tank 12 and the fuel tank 13 becomes excessive. When the pressure of the pressurized air supplied to the fuel tank 12 and the fuel tank 13 becomes excessive, the flow rates of light oil discharged from the fuel tank 12 and alcohol discharged from the fuel tank 13 become excessive, and proper fuel injection is performed. It becomes difficult. Therefore, the fuel supply control unit 19 monitors the pressure of the pressurized air supplied from the pressurized air generation unit 16 to the fuel tank 12 and the fuel tank 13. On the other hand, if the fuel supply control unit 19 determines that the pressure of the pressurized air acquired in S107 is smaller than the set lower limit value (S108: No), the fuel supply control unit 19 returns to S107 and continues to monitor the pressure of the pressurized air.

  When determining that the pressure of the pressurized air is smaller than the set upper limit value in S109 (S109: Yes), the fuel supply control unit 19 closes the leak valve 21 (S110) and closes the passage opening / closing valve 18 (S111). ). That is, when the fuel supply control unit 19 determines in S109 that the pressure of the pressurized air is smaller than the set upper limit value, the pressure of the air supplied from the pressurized air generation unit 16 to the fuel tank 12 and the fuel tank 13 is appropriate. It is judged that. Further, the pressures of the fuel tank 12 and the fuel tank 13 once increased do not greatly decrease with the normal fuel consumption accompanying the operation of the internal combustion engine 11. Therefore, the fuel supply control unit 19 closes the leak valve 21 and the passage opening / closing valve 18 to shut off the supply of pressurized air from the pressurized air generation unit 16 to the fuel tank 12 and the fuel tank 13. On the other hand, if the fuel supply control unit 19 determines in S109 that the pressure of the pressurized air is larger than the set upper limit value (S109: No), the fuel supply control unit 19 opens the leak valve 21 (S112). When the pressure of the pressurized air is larger than the set upper limit value, the pressure of the pressurized air passage 40 is excessive. Therefore, the fuel supply control unit 19 opens the leak valve 21 and reduces the pressure of the pressurized air passage 40. When the leak valve 21 is opened in S112, the fuel supply control unit 19 returns to S107 and continues to monitor the pressure in the pressurized air passage 40. In this way, the fuel supply control unit 19 maintains the pressure in the pressurized air passage 40 at a set pressure between the set lower limit value and the set upper limit value by opening and closing the leak valve 21.

  When the pressure of the pressurized air passage 40 is appropriate (S109: Yes), the fuel supply control unit 19 closes the passage opening / closing valve 18 in S110 and closes the leak valve 21 in S111, and then the second pressure sensor 47 again. To obtain the pressure of the pressurized air passage 40 (S113). That is, the fuel supply controller 19 continues to monitor the pressure of the pressurized air in the pressurized air passage 40, that is, the pressures of the fuel tank 12 and the fuel tank 13. Then, the fuel supply control unit 19 determines whether or not the pressure of the pressurized air passage 40 acquired in S113 is larger than the above-described set lower limit value (S114). As described above, in the normal operation of the internal combustion engine 11, the pressures of the fuel tank 12 and the fuel tank 13 are not significantly reduced. However, when the amount of fuel consumption increases, such as when a long-time operation or a high-load operation is continued, the pressure in the fuel tank 12 and the fuel tank 13 may fall below the set lower limit value. For this reason, the fuel supply control unit 19 closes the leak valve 21 and the passage opening / closing valve 18 in S110 and S111 and shuts off the supply of pressurized air from the pressurized air generation unit 16, and then the pressure of the pressurized air passage 40 Monitors whether the value falls below the set lower limit.

When the fuel supply control unit 19 determines that the pressure in the pressurized air passage 40 is smaller than the set lower limit value (S114: No), the fuel supply control unit 19 returns to S106 and opens the passage opening / closing valve 18. As a result, pressurized air is supplied to the pressurized air passage 40 from the pressurized air generator 16. Thereafter, the fuel supply control unit 19 repeats the processes after S107. On the other hand, if the fuel supply control unit 19 determines that the pressure in the pressurized air passage 40 is larger than the set lower limit value (S114: Yes), the process returns to S113 and continues to monitor the pressure in the pressurized air passage 40.
As described above, the fuel supply control unit 19 continues the above processing until the operation of the internal combustion engine 11 stops. Thus, the fuel supply control unit 19 maintains the pressure of the pressurized air passage 40, that is, the fuel tank 12 and the fuel tank 13 at a predetermined set pressure during the operation of the internal combustion engine 11 from the start of the internal combustion engine 11.

(When the internal combustion engine is stopped)
Next, the flow of operation when the internal combustion engine 11 to which the fuel supply device 10 is applied stops operation will be described with reference to FIG.
When the operation of the internal combustion engine 11 is stopped, the fuel supply control unit 19 stops the operation of the pressurized air generation unit 16 (S201). Subsequently, the fuel supply control unit 19 closes the passage opening / closing valve 18 (S202). As a result, the pressurized air passage 40 is closed by the passage opening / closing valve 18, and the air containing the vaporized fuel from the fuel tank 12 and the fuel tank 13 to the pressurized air generation unit 16 side through the pressurized air passage 40. Inflow is prevented. The fuel supply control unit 19 opens the leak valve 21 along with the closing of the passage opening / closing valve 18 (S203). Thereby, the pressurized air remaining in the fuel tank 12, the fuel tank 13 and the pressurized air passage 40 is discharged from the leak valve 21. As a result, the pressures of the fuel tank 12, the fuel tank 13, and the pressurized air passage 40 whose pressure is increased by the pressurized air gradually decrease.

  The fuel supply control unit 19 acquires the pressure of the pressurized air passage 40 from the second pressure sensor 47 (S204). That is, the fuel supply control unit 19 monitors the pressure of the pressurized air passage 40 that gradually decreases as the leak valve 21 is opened. Then, the fuel supply control unit 19 determines whether or not the pressure of the pressurized air passage 40 acquired in S204 has become smaller than a preset safety pressure (S205). As described above, when the fuel tank 12, the fuel tank 13, and the pressurized air passage 40 are pressurized with pressurized air, the lid of the fuel filler port 43 of the fuel tank 12 and the lid of the fuel filler port 44 of the fuel tank 13 are opened. There is a risk of fuel blowing out. Therefore, the fuel supply control unit 19 determines whether or not the pressure of the pressurized air passage 40 has decreased to a safe pressure that prevents the fuel from blowing out even when the lid of each fuel filler opening is opened. This safety pressure is set as a value close to atmospheric pressure, for example.

  When the fuel supply control unit 19 determines that the pressure of the pressurized air has not decreased to the safe pressure (S205: No), the fuel supply control unit 19 turns on a warning lamp (not shown) (S206). That is, the fuel supply control unit 19 turns on the warning lamp to warn the user of the internal combustion engine 11 that fuel may be blown out from the fuel tank 12 and the fuel tank 13. This warning may be performed by any means such as sounding an alarm sound or locking the lid of the fuel filler opening 43 of the fuel tank 12 and the lid of the fuel filler opening 44 of the fuel tank 12 instead of turning on the warning lamp. . The fuel supply control unit 19 turns on the warning lamp in S206 and then returns to S204 to continue monitoring the pressure and comparing with the safety pressure.

When the fuel supply control unit 19 determines that the pressure of the pressurized air has decreased to the safe pressure (S205: Yes), the fuel supply control unit 19 may open the lid of the fuel filler port 43 of the fuel tank 12 and the lid of the fuel filler port 44 of the fuel tank 13. A good message is displayed (S207). That is, the fuel supply control unit 19 may open the fuel tank 12 and the fuel tank 13 when determining that the pressures of the fuel tank 12 and the fuel tank 13 have decreased to such an extent that fuel does not blow out from the respective fuel filler ports. Is displayed. At this time, the fuel supply control unit 19 turns off the warning lamp displayed in S206.
By the above procedure, the fuel supply control unit 19 causes the fuel tank 12, the fuel tank 13, and the pressurized air passage 40 to the extent that fuel does not blow out from the fuel tank 12 and the fuel tank 13 when the internal combustion engine 11 is stopped. Reduce the pressure.

  In the embodiment of the present invention described above, the pressurized air generation unit 16 and the fuel tank 12 and the fuel tank 13 are connected by the pressurized air passage 40. The fuel supply controller 19 supplies pressurized air from the pressurized air generator 16 to the fuel tank 12 and the fuel tank 13 by opening the pressurized air passage 40. As a result, the fuel tank 12 and the fuel tank 13 are pressurized by the supplied pressurized air, and the stored fuel is supplied to the fuel injection unit 14 and the fuel injection unit 15, respectively. That is, by supplying pressurized air from the single pressurized air generator 16 to the fuel tank 12 and the fuel tank 13, the fuel stored in the fuel tank 12 and the fuel tank 13 is pushed out by the pressurized air. The fuel is supplied to the injection unit 14 and the fuel injection unit 15. As a result, no separate pump or the like is required from the fuel tank 12 and the fuel tank 13 to the fuel injection unit 14 and the fuel injection unit 15. Therefore, a plurality of types of liquid fuel can be individually supplied to the internal combustion engine 11 with a simple structure without increasing the number of parts.

  In one embodiment, a fuel injection unit 14 and a fuel injection unit 15 are provided for each type of fuel. That is, a plurality of types of fuel stored in the fuel tank 12 and the fuel tank 13 are supplied to the fuel injection unit 14 and the fuel injection unit 15 without being mixed. Therefore, different types of fuel can be supplied to the fuel injection unit 14 and the fuel injection unit 15 in accordance with the operating state of the internal combustion engine 11.

  In one embodiment, the passage opening / closing valve 18 closes the pressurized air passage 40 when the internal combustion engine 11 stops operating. As a result, when the internal combustion engine 11 is not in operation, the flow of air from the fuel tank 12 and the fuel tank 13 to the pressurized air generator 16 via the pressurized air passage 40 is blocked by the passage opening / closing valve 18. It is done. Therefore, the inflow of air including fuel from the pressurized fuel tank 12 and the fuel tank 13 to the pressurized air generation unit 16 side is prevented. Therefore, it is possible to reduce the deterioration and performance degradation of the pressurized air generation unit 16.

  In one embodiment, the leak valve 21 maintains the pressure inside the pressurized air passage 40, the fuel tank 12, and the fuel tank 13 at a set pressure. This set pressure is preset in a predetermined range between the set upper limit value and the set lower limit value. As a result, the pressure of the fuel supplied from the fuel tank 12 to the fuel injection unit 14 and from the fuel tank 13 to the fuel injection unit 15 is adjusted within the set pressure range. Therefore, the fuel can be stably supplied to the fuel injection unit 14 and the fuel injection unit 15.

  In one embodiment, the leak valve 21 opens when fuel is supplied to the fuel tank 12 and the fuel tank 13. Thereby, the pressure inside the fuel tank 12, the fuel tank 13, and the pressurized air passage 40 is maintained at a pressure lower than the set pressure. The insides of the fuel tank 12, the fuel tank 13, and the pressurized air passage 40 are adjusted to a pressure close to atmospheric pressure, for example, when the leak valve 21 is opened. For this reason, when fuel is supplied to the fuel tank 12 and the fuel tank 13, the fuel in the fuel tank 12 and the fuel tank 13 does not blow out to the outside. Therefore, safety can be improved.

(Other embodiments)
The present invention described above is not limited to the above-described embodiment, and can be applied to various embodiments without departing from the gist thereof.
For example, in the above description, the internal combustion engine 11 is described as an example of a diesel engine that uses light oil and alcohol as fuel. However, the internal combustion engine 11 is not limited to a diesel engine as long as it uses a plurality of fuels, and can be applied to other types such as a gasoline engine. In the above-described embodiment, the fuel supply device 10 including the two fuel tanks 12 and the fuel tank 13 corresponding to two types of fuel has been described as an example. However, in order to supply two or more types of fuel to the internal combustion engine 11, a configuration including two or more fuel tanks may be employed.

  In the drawings, 10 is a fuel supply device, 11 is an internal combustion engine, 12 and 13 are fuel tanks, 14 and 15 are fuel injection sections, 16 is a pressurized air generating section, 17 is a pressurized air passage section, and 18 is a passage opening / closing valve. , 19 is a fuel supply control unit, 21 is a leak valve, and 40 is a pressurized air passage.

Claims (3)

A plurality of fuel tanks each storing different types of liquid fuel;
A fuel injection unit that injects fuel stored in the fuel tank into the internal combustion engine;
A pressurized air generator for pressurizing air;
Pressurized air that connects the pressurized air generation unit and the plurality of fuel tanks to form a pressurized air passage through which pressurized air supplied from the pressurized air generation unit to the plurality of fuel tanks flows. A passage section;
A passage opening / closing valve for opening and closing the pressurized air passage portion;
The fuel stored in the fuel tank is supplied to the fuel injection portion by opening the pressurized air passage portion with the passage opening / closing valve and supplying pressurized air from the pressurized air generating portion to the fuel tank. A fuel supply control unit to supply;
A leak valve for maintaining the pressure inside the pressurized air passage and the fuel tank at a set pressure within a preset range;
The leak valve is opened when fuel is supplied to the fuel tank from the outside, and the pressure inside the pressurized air passage and the fuel tank is maintained at a pressure lower than the set pressure. Fuel supply device.   The fuel supply device according to claim 1, wherein the fuel injection unit is individually provided for each type of the liquid fuel stored in the fuel tank.   The passage opening / closing valve cuts off the flow of air from the fuel tank to the pressurized air generation section via the pressurized air passage section when the internal combustion engine stops operating. Item 3. The fuel supply device according to Item 1 or 2.

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