JP2008286004A - Fuel supply system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To supply fuel of stable ignitability, regardless of properties of original fuel. <P>SOLUTION: This fuel supply system 10 has a main tank 11, an alcohol concentration sensor 15, a reforming delivery pipe 14 and an ECU 17. The ECU 17 supplies the fuel to an engine 30 via the reforming delivery pipe 14 from the main tank 11 at a cold time. The reforming delivery pipe 14 has an ultrasonic wave generator 18. The alcohol concentration sensor 15 detects the alcohol concentration of mixed fuel stored in the main tank 11. An alcohol concentration signal is transmitted to the ECU 17. The ECU 17 generates an ultrasonic wave of an amplitude corresponding to the alcohol concentration by the ultrasonic wave generator 18. The mixed fuel passing through the reforming delivery pipe 14 is reformed by the ultrasonic wave. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a fuel supply system capable of reforming and supplying various types of fuel to an internal combustion engine.

In recent years, an internal combustion engine capable of burning a plurality of types of fuel such as gasoline and alcohol fuel has been proposed. In order to ensure ignitability at the time of operation of such an internal combustion engine, particularly at the time of starting, it has been proposed that a part of the fuel in the tank is reformed into a fuel that is easily vaporized and supplied to the internal combustion engine ( Patent Document 1).
Japanese Patent Laid-Open No. 5-223026

  By the way, when a plurality of types of fuel are used, the chemical characteristics of the fuel are not always constant. Therefore, the problem is that the ignitability of the fuel after reforming also varies. That is, the ignitability of the reformed fuel is insufficient, and it may take time for the first explosion.

  An object of the present invention is to provide a fuel supply system that supplies a fuel having a stable property to an internal combustion engine capable of burning a plurality of types of fuel.

  A fuel supply system according to a first aspect supplies fuel to an internal combustion engine. The fuel supply system usually includes a fuel tank, reforming means, property detection means, and control means. The normal fuel tank stores raw fuel that is fuel supplied to the internal combustion engine. The reforming means reforms the raw fuel into a reformed fuel having higher ignitability than the raw material. The property detection means detects the fuel property of the raw fuel that affects the ignitability of the reformed fuel. The control means adjusts the reforming level of the reforming means in accordance with the fuel property of the raw fuel detected by the property detecting means. The reforming level is a degree of lightening the distillation characteristics of the reformed fuel produced.

  According to the first invention, since the reforming level is adjusted according to the fuel property, it becomes possible to supply a stable ignitable reformed fuel regardless of the fuel property of the raw fuel.

  The fuel supply system according to the second invention includes an initial explosion detection means in addition to the configuration of the first invention. The first explosion detection means detects whether or not the internal combustion engine has completed the first explosion. The control means adjusts the reforming level until the initial explosion detecting means detects the first explosion of the internal combustion engine.

  According to the second aspect of the invention, it is possible to reliably adjust the reforming level and supply a stable ignitable reformed fuel during the start-up period in which high ignitability is particularly required.

  A fuel supply system according to a third invention includes a reformed fuel tank in addition to the configuration of the first invention. The reformed fuel tank stores the reformed fuel. The control unit supplies the reformed fuel stored in the reformed fuel tank to the internal combustion engine when the fuel property of the raw fuel detected by the property detecting unit exceeds the first threshold value, and the raw fuel stored in the normal fuel tank. The fuel is reformed by the reforming means, and the reformed fuel tank is replenished.

  According to the third invention, when the ignitability of the reformed fuel is estimated to be low from the properties of the raw fuel, the fuel having high ignitability is supplied by supplying the reformed fuel stored in the reformed fuel tank to the internal combustion engine. Can be reliably and stably supplied to the internal combustion engine. In addition, it is possible to prevent the reformed fuel tank from being deficient by replenishing the reformed fuel tank with the reformed fuel during the supply of fuel from the reformed fuel tank.

  A fuel supply system according to a fourth aspect of the invention includes initial explosion detection means in addition to the configuration of the third aspect of the invention. The first explosion detection means detects whether or not the internal combustion engine has completed the first explosion. Until the initial explosion detection means detects the first explosion of the internal combustion engine, the control means supplies the reformed fuel to the internal combustion engine and replenishes the reformed fuel tank with the reformed raw fuel.

  According to the fourth aspect of the invention, it is possible to reliably adjust the reforming level and supply a stable ignitable reformed fuel during the start-up period in which high ignitability is particularly required.

  A fuel supply system according to a fifth aspect of the invention includes a storage amount detection means in addition to the configuration of the third aspect of the invention. The storage amount detection means detects the storage amount of the reformed fuel stored in the reformed fuel tank. The control means causes the reforming means to reform the raw fuel stored in the normal fuel tank until the storage amount detected by the storage amount detection means exceeds the second threshold, and replenishes the reformed fuel tank.

According to the fifth aspect, it is possible to keep the amount of reformed fuel stored in the reformed fuel tank at or above the second threshold. By keeping the amount of reformed fuel stored above the second threshold, it is possible to secure reformed fuel for immediate supply when it is necessary to supply reformed fuel to the engine thereafter. is there.

  A fuel supply system according to a sixth aspect supplies fuel to an internal combustion engine. The fuel supply system includes a normal fuel tank, reforming means, reformed fuel tank, property detection means, and control means. The normal fuel tank stores raw fuel that is fuel supplied to the internal combustion engine. The reforming means reforms the raw fuel into a reformed fuel having higher ignitability than the raw fuel. The reformed fuel tank stores the reformed fuel. The property detection means detects the fuel property of the raw fuel that affects the ignition of the reformed fuel. The control unit supplies the reformed fuel stored in the reformed fuel tank to the internal combustion engine when the fuel property of the raw fuel detected by the property detecting unit exceeds a threshold value, and modifies the raw fuel stored in the normal fuel tank. The reforming fuel tank is replenished with the quality means.

  According to the sixth aspect of the present invention, a fuel having high ignitability by supplying the reformed fuel stored in the reformed fuel tank to the internal combustion engine when it is estimated that the ignitability of the reformed fuel is lowered from the properties of the raw fuel. Can be reliably and stably supplied to the internal combustion engine. In addition, it is possible to prevent the reformed fuel tank from being deficient by replenishing the reformed fuel tank with the reformed fuel during the supply of fuel from the reformed fuel tank.

  According to the present invention, it is possible to supply reformed fuel having stable ignitability to an internal combustion engine regardless of the properties of the fuel normally stored in the fuel tank.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a configuration diagram of a fuel supply system to which an embodiment of the present invention is applied.

  The fuel supply system 10 includes a main tank 11, a reformed fuel tank 12, a normal delivery pipe 13, a reformed delivery pipe 14, an alcohol concentration sensor 15, first to fourth switching valves 16a to 16d, an ECU 17, and the like. Composed.

  The main tank 11 is connected to the first switching valve 16a. The first switching valve 16a is connected to the normal delivery pipe 13 via the reforming delivery pipe 14 and the second switching valve 16b. The main tank 11 stores normal gasoline or a mixed fuel of gasoline and alcohol fuel. The mixed fuel stored in the main tank 11 is sent to one or both of the reforming delivery pipe 14 and the normal delivery pipe 13 by the first switching valve 16a.

  The second switching valve 16b is connected to the first switching valve 16a and the normal delivery pipe 13 as described above. The second switching valve 16 b is connected to the reformed fuel tank 12. Either the first switching valve 16a or the reformed fuel tank 12 is communicated with the normal delivery pipe 13 by the second switching valve 16b. Therefore, the fuel stored in either the main tank 11 or the reformed fuel tank 12 is sent to the normal delivery pipe 13.

  The normal delivery pipe 13 and the reformed delivery pipe 14 are connected to the third switching valve 16c. Further, the third switching valve 16 c is connected to the engine 30. One of the normal delivery pipe 13 and the reformed delivery pipe 14 is communicated with the engine 30 by the third switching valve 16c. Therefore, the fuel that is normally sent via the delivery pipe 13 or the reforming delivery pipe 14 is supplied to the engine 30.

  A fourth switch valve 16d is provided between the reforming delivery pipe 14 and the third switch valve 16c. The fourth switching valve 16 d is connected to the reformed fuel tank 12. The fuel that flows out of the reforming delivery pipe 14 is sent to either the reforming fuel tank 12 or the engine 30 by the fourth switching valve 16d.

  The modified delivery pipe 14 is provided with an ultrasonic generator 18. The ultrasonic generator 18 is formed by a piezoelectric element (not shown) and a drive circuit (not shown). The ultrasonic generator 18 applies ultrasonic waves to the fuel in the reforming delivery pipe 14. The fuel passing through the reforming delivery pipe 14 is reformed by ultrasonic waves, and a reformed fuel that is lighter than the original fuel is generated.

  The ultrasonic generator 18 is controlled by the ECU 17. The amplitude of the ultrasonic wave generated by the ultrasonic generator 18 is adjusted by a control signal transmitted from the ECU 17. By adjusting the amplitude, the reforming level in the reforming delivery pipe 14, that is, the degree of lightening the distillation characteristics of the reformed fuel produced is adjusted.

  The first to fourth switching valves 16a to 16d are connected to the ECU 17 via a drive circuit (not shown). Switching of the first to fourth switching valves 16a to 16d is controlled by the ECU 17 as will be described later.

  The main tank 11 is provided with an alcohol concentration sensor 15. The alcohol concentration sensor 15 detects the alcohol concentration of the stored mixed fuel. The detected alcohol concentration is transmitted to the ECU 17 as a signal. The reformed fuel tank 12 is provided with a liquid level sensor 19. The liquid level sensor 19 detects the height of the liquid level of the reformed fuel stored in the reformed fuel tank 12. The detected liquid level is transmitted to the ECU 17 as a signal.

  The engine 30 is provided with a water temperature sensor (not shown) and a rotation sensor (not shown). The coolant temperature and the rotation speed of the engine 30 are detected by the water temperature sensor and the rotation sensor, respectively. The detected coolant temperature and rotation speed are transmitted to the ECU 17 as signals.

  The ECU 17 controls the fuel supply system 10 based on the alcohol concentration, the cooling water temperature, the rotation speed, and the liquid level. Further, the ECU 17 controls the fuel injection amount and ignition timing in the engine 30 based on the coolant temperature and the rotational speed.

  Next, the first fuel supply control that the ECU 17 causes each part of the fuel supply system 10 to execute according to the alcohol concentration according to the present embodiment will be described using the flowchart of FIG. 2. In the first fuel supply control, various operations are executed at a time determined for each step.

  In step S100, the ECU 17 acquires water temperature data of the engine 30. In the next step S101, the ECU 17 determines whether or not the engine 30 is in a cold state based on the acquired water temperature data. The cold state is determined based on whether or not the water temperature exceeds the threshold temperature. When the engine 30 is in the cold state, the process proceeds to step S102. When the engine is not cold, step S102 to step S110 are skipped and the process proceeds to step S111.

  In step S102, the ECU 17 acquires alcohol concentration data of the mixed fuel stored in the main tank 11. In step S103, the ECU 17 determines whether or not the alcohol concentration of the mixed fuel is 100%. When the alcohol concentration is less than 100%, the process proceeds to step S104. When the alcohol concentration is substantially 100%, the process proceeds to step S106.

  In step S <b> 104, the first switching valve 16 a is switched so that the mixed fuel stored in the main tank 11 is sent to the reforming delivery pipe 14. Further, the third and fourth switching valves 16c and 16d are switched so that the reformed fuel generated by reforming the mixed fuel in the reforming delivery pipe 14 is sent to the engine 30. By such switching operation of the first, third, and fourth switching valves 16a, 16c, and 16d, the mixed fuel stored in the main tank 11 is reformed by the reforming delivery pipe 14 and supplied to the engine 30. The

  In the next step S105, the ECU 17 adjusts the amplitude of the ultrasonic wave so as to obtain a reforming level corresponding to the alcohol concentration detected in step S102. Note that the reforming level increases as the alcohol concentration increases. When the amplitude of the ultrasonic wave is adjusted, the process proceeds to step S108.

  On the other hand, when the process proceeds to step S106, the second switching valve 16b is switched so that the reformed fuel stored in the reformed fuel tank 12 is sent to the normal delivery pipe 13. Further, the third switching valve 16 c is switched so that the reformed fuel that normally flows out from the delivery pipe 13 is sent to the engine 30. The reformed fuel stored in the reformed fuel tank 12 is supplied to the engine 30 by the switching operation of the second and third switching valves 16b and 16c.

  In the next step S107, the first switching valve 16a is switched so that the mixed fuel stored in the main tank 11 is sent to the reforming delivery pipe 14. Further, the fourth switching valve 16 d is switched so that the reformed fuel generated by reforming the mixed fuel in the reforming delivery pipe 14 is sent to the reformed fuel tank 12. By such switching operation of the first and fourth switching valves 16 a and 16 d, the mixed fuel stored in the main tank 11 is reformed and replenished to the reformed fuel tank 12. After the start of replenishment of the reformed fuel, the process proceeds to step S108.

  In step S108, the ECU 17 acquires rotation speed data of the engine 30. In the next step S109, the ECU 17 determines whether or not the initial explosion has been completed based on the acquired rotation speed data. When the detected rotation speed exceeds the rotation speed by driving a cell motor (not shown), it is determined that the initial explosion has been completed.

  When the initial explosion is not completed, the process returns to step S108, and thereafter, the processes of steps S108 and S109 are repeated until the initial explosion is completed. When the first explosion is completed, the process proceeds to step S110.

  In step S110, the ECU 17 stops the ultrasonic generator 18 and stops the reforming of the mixed fuel. In the next step S111, the first and second switching valves 16a and 16b are switched so that the mixed fuel stored in the main tank 11 is sent to the normal delivery pipe 13. Further, the third switching valve 16 c is switched so that the mixed fuel flowing out from the normal delivery pipe 13 is sent to the engine 30. The mixed fuel stored in the main tank 11 is supplied to the engine 30 by the switching operation of the first to third switching valves 16a to 16c. After supplying the mixed fuel, the process returns to step S100.

  Next, the second fuel supply control that the ECU 17 causes each part of the fuel supply system 10 to execute according to the alcohol concentration according to the present embodiment will be described using the flowchart of FIG. 3. Note that the second fuel supply control is executed by interruption every predetermined time.

  In step S200, the ECU 17 acquires liquid level height data. In the next step S201, the ECU 17 determines whether or not the liquid level of the reformed fuel tank 12 exceeds the threshold based on the acquired liquid level data. When the liquid level is below the threshold, the process proceeds to step S202. When the height of the liquid level exceeds the threshold value, the process proceeds to step S203.

  In step S202, the first switching valve 16a is switched so that the mixed fuel stored in the main tank 11 is sent to the normal delivery pipe 13 and the reforming delivery pipe 14. Further, the ECU 17 drives the ultrasonic generator 18 to reform the mixed fuel that passes through the reforming delivery pipe 14. After the reforming of the mixed fuel, the process returns to step S200, and thereafter, the processes of step S200 to step S202 are repeated until the liquid level exceeds the threshold value in step S201.

  In step S203, the ECU 17 stops the ultrasonic generator 18 and ends the reforming of the mixed fuel.

  According to the fuel supply system configured as described above, the reforming level increases as the alcohol concentration in the mixed fuel increases. Alcohol fuel is difficult to reform to light fuel compared to gasoline. Therefore, it is possible to stabilize the ignitability of the reformed fuel at a certain level by raising the reforming level according to the concentration of the alcohol fuel.

  In the present embodiment, the mixed fuel stored in the main tank 11 is a mixed fuel of gasoline and alcohol fuel, but may be a mixed fuel obtained by mixing other types of fuel. If it is a mixed fuel obtained by mixing different types of fuels having different ignitability after reforming, the same effect as in the present embodiment is exhibited.

  Further, in this embodiment, the alcohol concentration of the mixed fuel is detected, and the reforming level is adjusted according to the detected alcohol concentration, but other properties of the mixed fuel are detected and the detected properties are obtained. The structure which adjusts a modification | reformation level based on may be sufficient. If a property that affects the ignitability of the reformed fuel after reforming is detected and the reforming level is adjusted, the same effect as in the present embodiment is exhibited.

  In the present embodiment, the mixed fuel is reformed using the ultrasonic generator 18, but another reformer capable of adjusting the reforming level may be used. For example, steam reforming or reforming by thermal decomposition may be performed.

  In the present embodiment, the reformed fuel stored in the reformed fuel tank 12 is supplied to the engine 30 when the alcohol concentration is 100%, but the reformed fuel is modified when the alcohol concentration exceeds a predetermined threshold. The configuration may be such that the quality fuel is supplied to the engine 30.

  In the present embodiment, either the adjustment of the reforming level according to the alcohol concentration or the supply of the reformed fuel from the reformed fuel tank 12 to the engine 30 is based on whether the alcohol concentration is 100%. However, only one of them may be performed. Even when either one is performed, it is possible to supply the engine 30 with fuel having a stable property as compared with the conventional fuel supply device.

  In the present embodiment, the reforming according to the alcohol concentration or the supply of the reformed fuel from the reformed fuel tank 12 is performed until the initial explosion is completed. You don't have to. Even after completion of the initial explosion, reforming according to the alcohol concentration or supply of reformed fuel from the reformed fuel tank 12 allows the engine 30 to provide stable ignitable fuel not only during start-up but also during normal operation. Can be sent to.

  In the present embodiment, when the liquid level of the reformed fuel tank 12 is low, the reformed fuel is generated by reforming the mixed fuel stored in the main tank 11 to reform the reformed fuel. Although the fuel tank 12 is replenished, the reformed fuel need not be automatically replenished. Even without replenishing the reformed fuel, it is possible to obtain the effect of stabilizing the ignitability.

1 is a configuration diagram of a fuel supply system to which an embodiment of the present invention is applied. It is a flowchart which shows the structure of the program of the 1st fuel supply control which ECU performs. It is a flowchart which shows the structure of the program of the 2nd fuel supply control which ECU performs.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Fuel supply system 11 Main tank 12 Reformed fuel tank 13 Normal delivery pipe 14 Reformed delivery pipe 15 Alcohol concentration sensor 16a-16d 1st-4th switching valve 17 ECU
18 Ultrasonic generator 19 Liquid level sensor 30 Engine

Claims (6)

A fuel supply system for supplying fuel to an internal combustion engine,
A normal fuel tank for storing raw fuel that is fuel to be supplied to the internal combustion engine;
Reforming means for reforming the raw fuel into a reformed fuel having higher ignitability than the raw fuel;
Property detecting means for detecting the fuel property of the raw fuel affecting the ignitability of the reformed fuel;
A fuel supply system comprising: control means for adjusting a reforming level of the reforming means in accordance with the fuel property of the raw fuel detected by the property detecting means.   Initial explosion detection means for detecting whether or not the internal combustion engine has completed the initial explosion, and the control means adjusts the reforming level until the initial explosion detection means detects the initial explosion of the internal combustion engine. The fuel supply system according to claim 1, wherein the fuel supply system is performed. A reformed fuel tank for storing the reformed fuel;
The control means causes the internal combustion engine to supply the reformed fuel stored in the reformed fuel tank when the fuel property of the raw fuel detected by the property detection means exceeds a first threshold value, 2. The fuel supply system according to claim 1, wherein the raw fuel stored in a normal fuel tank is reformed by the reforming unit and replenished to the reformed fuel tank. 3.   An initial explosion detecting means for detecting whether or not the internal combustion engine has completed an initial explosion; and the control means until the initial explosion detecting means detects the initial explosion of the internal combustion engine, The fuel supply system according to claim 3, wherein supply to the engine and replenishment of the reformed raw fuel to the reforming tank are performed. A storage amount detecting means for detecting a storage amount of the reformed fuel stored in the reformed fuel tank;
The control means causes the reforming means to reform the raw fuel stored in the normal fuel tank until the storage amount detected by the storage amount detection means exceeds a second threshold value, so that the reforming fuel tank The fuel supply system according to claim 3, wherein the fuel supply system is replenished. A fuel supply system for supplying fuel to an internal combustion engine,
A normal fuel tank for storing raw fuel that is fuel to be supplied to the internal combustion engine;
Reforming means for reforming the raw fuel into a reformed fuel having higher ignitability than the raw fuel;
A reformed fuel tank for storing the reformed fuel;
Property detecting means for detecting the fuel property of the raw fuel affecting the ignitability of the reformed fuel;
When the fuel property of the raw fuel detected by the property detection means exceeds a threshold value, the reformed fuel stored in the reformed fuel tank is supplied to the internal combustion engine, and the normal fuel tank stores the reformed fuel. A fuel supply system comprising: control means for reforming the raw fuel into the reforming means and replenishing the reformed fuel tank.

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