JP2009191724A - Fuel supply device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To supply a fuel injection valve with a necessary quantity of fuel without shortage in a status that the temperature of fuel is high and a demand fuel injection quantity of the fuel injection valve is large during the operation of an internal combustion engine without using a pump of an excessively large capacity. <P>SOLUTION: A fuel pump 6 out of the first fuel pump 6 and a second fuel pump 7 is an electric pump changing a delivery quantity according to a supply voltage. The device is provided with a supply voltage adjusting means 30 setting a supply voltage to the fuel pump 6 higher when the conditions that the temperature of fuel detected by a fuel temperature detection means 23 is not lower than a prescribed temperature and a demand fuel injection quantity of the fuel injection valve 3 is not smaller than a prescribed quantity are satisfied, than that when the conditions are not satisfied. The supply voltage adjusting means 30 raises the supply voltage to the fuel pump 6 by carrying out the power generation operation of a generator 13. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a fuel supply device for an internal combustion engine.

  In an internal combustion engine that requires high-pressure fuel injection, such as an in-cylinder internal combustion engine or a diesel engine, the fuel in the fuel tank is sucked and discharged by an electric low-pressure pump and discharged from the low-pressure pump. Is supplied to a high-pressure pump driven by the internal combustion engine to increase the pressure to high pressure, and high-pressure fuel discharged from the high-pressure pump is supplied to a fuel injection valve of each cylinder of the internal combustion engine through a common rail having a pressure accumulation function. In general, there is known a fuel supply device including a fuel supply device (see, for example, Patent Document 1).

In Patent Document 1, when the temperature of the fuel is relatively high at the time of starting the internal combustion engine, the pressure of the fuel is difficult to increase due to the vapor of the fuel. A technique for increasing the discharge amount of a low-pressure pump when the temperature of the fuel is higher than a predetermined temperature is described.
JP 2002-61529 A

  By the way, in this type of fuel supply device, the temperature of the fuel may become high due to heat generated in the internal combustion engine during operation of the internal combustion engine. When the temperature of the fuel becomes high in this way, fuel leaks easily occur in the high-pressure pump, the common rail, or the fuel injection valve due to the low viscosity of the fuel. For this reason, in particular, when the required fuel injection amount of the fuel injection valve is relatively large, the actual amount of fuel supplied to the fuel injection valve is reduced even if the fuel pressure in the common rail is an appropriate pressure. There is a risk that the required fuel injection amount of the fuel injection valve will be insufficient.

  In order to avoid such an inconvenience, for example, it is conceivable to use a low-pressure pump having a large capacity capable of always supplying a sufficient amount of fuel in anticipation of the fuel leak. However, the use of such a low-pressure pump leads to an increase in size and cost of the fuel supply device, and excessive energy consumption in the low-pressure pump under many operating conditions of the internal combustion engine.

  Further, as seen in Patent Document 1, only when the internal combustion engine is started, even when the discharge amount of the low-pressure pump is increased when the temperature of the fuel is high, during the operation after the start. When the required fuel injection amount of the fuel injection valve increases, it is impossible to avoid a shortage of the actual amount of fuel supplied to the fuel injection valve.

  The present invention has been made in view of such a background, and the fuel temperature is high and the required fuel injection amount of the fuel injection valve is high during operation of the internal combustion engine without using an excessively large capacity pump. An object of the present invention is to provide a control device for a fuel supply device that can supply a required amount of fuel to a fuel injection valve without a shortage in a situation where there are many fuel injection valves.

  In order to achieve the above object, a fuel supply device of the present invention includes a first fuel pump that sucks and discharges fuel in a fuel tank, and boosts the fuel discharged from the first fuel pump to internal combustion. In the control device of the fuel supply device including the second fuel pump that supplies the fuel injection valve of the engine, the first fuel pump is constituted by an electric pump that increases the discharge amount as the supply voltage increases. A fuel temperature detecting means for detecting the temperature of the fuel; a temperature detected by the fuel temperature detecting means is not less than a predetermined temperature; and a required fuel injection amount of the fuel injection valve is not less than a predetermined amount. A supply voltage adjusting unit that determines whether or not a certain condition is satisfied and makes the supply voltage of the first fuel pump higher when the condition is satisfied than when the condition is not satisfied; Features To (first invention).

  When the first fuel pump is constituted by an electric pump that increases the discharge amount as the supply voltage to the first fuel pump increases, the discharge amount of the first fuel pump is increased by increasing the supply voltage. Can be increased. Therefore, in the first invention, whether or not the condition that the temperature of the fuel detected by the fuel temperature detecting means is not less than a predetermined temperature and the required fuel injection amount of the fuel injection valve is not less than a predetermined amount is satisfied. And supply voltage adjusting means for making the supply voltage of the first fuel pump higher when the condition is satisfied than when the condition is not satisfied. For this reason, when the above condition is satisfied, the discharge amount of the first fuel pump is increased as compared with the case where the condition is not satisfied. In the first invention, in a situation where the above condition is not satisfied, the discharge amount of the first fuel pump can be reduced by appropriately reducing the supply voltage of the first fuel pump.

  Therefore, according to the first invention, the fuel temperature is high and the required fuel injection amount of the fuel injection valve is large during operation of the internal combustion engine without using an excessively large capacity pump. The required amount of fuel can be supplied to the fuel injection valve without any shortage.

  In the first aspect of the invention, as a more specific form of the supply voltage adjusting means, for example, the following form can be considered.

  That is, the supply voltage adjusting means includes: the first fuel pump; a capacitor; and a generator capable of generating power to charge the capacitor and generating an output voltage higher than the capacitor during the power generation operation. The power supply is connected to the capacitor and the generator so as to receive the supply voltage, and the supply voltage adjusting means performs the power generation operation of the generator when the condition is satisfied when the power generation operation of the generator is stopped. This is means for making the supply voltage of the first fuel pump higher than when the condition is not satisfied (second invention).

  Here, when the internal combustion engine is mounted on a vehicle, for example, as a propulsive force generation source of the vehicle, usually, the vehicle includes a capacitor as a power source for electrical components such as the first fuel pump, and the like. And a generator capable of generating operation for charging the battery, and a first fuel pump is connected to the power storage unit and the generator. During the power generation operation of the power generator, the power generator generates an output voltage higher than that of the battery, and the output voltage is supplied to the first fuel pump. Therefore, in the second invention, when the condition is satisfied when the generator operation of the generator is stopped, the supply voltage adjusting means causes the generator to perform the generator operation, whereby the first fuel pump The supply voltage is set higher than when the condition is not satisfied.

  According to the second invention, since the supply voltage of the first fuel pump can be increased or decreased only by controlling the operation of the generator, the present invention can be constructed at a low cost with a simple configuration using existing equipment. .

  An embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 is a diagram schematically showing a system configuration relating to a fuel supply apparatus in the present embodiment. Referring to FIG. 1, a fuel supply device 1 according to this embodiment is a device that supplies fuel to a fuel injection valve 3 of an internal combustion engine 2 mounted as a propulsive force generation source in a vehicle, for example. The internal combustion engine 2 is, for example, a diesel engine, and its fuel injection valve 3 is assembled to the internal combustion engine 2 so as to inject fuel directly into each cylinder 4 of the internal combustion engine 2. In FIG. 1, only the fuel injection valves 3 corresponding to one cylinder 4 are representatively described. However, in reality, fuel injection valves corresponding to the number of cylinders of the internal combustion engine 2 are provided for each cylinder. Yes.

  The fuel supply apparatus 1 includes a fuel tank 5 that stores fuel, a low-pressure pump 6 as a first fuel pump that sucks and discharges fuel in the fuel tank 5, and fuel discharged from the low-pressure pump 6. And a high-pressure pump 7 as a second fuel pump that discharges after increasing the pressure to a high pressure. The high-pressure fuel discharged from the high-pressure pump 7 is injected into each cylinder 4 through a common rail 8 having a pressure accumulation function. The valve 3 is supplied.

  The low-pressure pump 6 is disposed in the fuel tank 1 and supplies the sucked fuel in the fuel tank 1 to the high-pressure pump 7 via the low-pressure side supply pipe 9. A filter 10 for removing impurities in the fuel is interposed in the low-pressure side supply pipe 9.

  The low-pressure pump 6 is an electric pump, and is electrically connected to a battery 11 composed of a secondary battery and a capacitor via an inverter circuit 12. The low-pressure pump 6 is connected from the battery 11 via the inverter circuit 12. Is supplied with power for the operation. In addition, a generator 13 driven by the internal combustion engine 2 is electrically connected to a power supply line between the battery 11 and the inverter circuit 12 via an inverter circuit 14, and the generated power of the generator 13 is converted into an inverter circuit. The battery 11 is charged via the power supply 14 and simultaneously supplied to the low-pressure pump 6. Therefore, the low pressure pump 6 is operated by the electric power supplied from the battery 11 or the generator 13.

  Here, the low pressure pump 6 is electrically driven in such a manner that the higher the supply voltage (the input voltage of the inverter circuit 12), the higher the fuel discharge amount (more specifically, the maximum amount of fuel that can be discharged per unit time). Pump. Further, during the power generation operation of the generator 13 (when the armature winding of the generator 13 is energized), the generator 13 is output from the generator 13 via the inverter circuit 14 in order to charge the power storage 11. The power generation operation of the generator 13 is performed so that the direct current voltage becomes slightly higher than the output voltage (voltage between terminals) of the battery 11. For this reason, the supply voltage to the low-pressure pump 6 becomes the output voltage (for example, 12.5 V) of the battery 11 when the power generation operation of the generator 13 is stopped (when the armature winding of the generator 13 is turned off), During the power generation operation of the generator 13, the voltage is higher than the output voltage of the battery 11 (for example, 14.5V). Accordingly, the fuel discharge amount of the low-pressure pump 6 is increased during the power generation operation of the generator 13 than when the power generation operation of the generator 13 is stopped.

  The high-pressure pump 7 is a mechanically driven pump driven by the internal combustion engine 2, boosts the fuel supplied from the low-pressure pump 6 through the low-pressure side supply pipe 9 to a high pressure, and supplies the high-pressure fuel to a pair. Are supplied to the common rail 5 via the high-pressure side supply pipes 15 and 15. The high-pressure pump 7 includes, for example, a plunger (not shown) that reciprocates in conjunction with the output shaft of the internal combustion engine 2 and a fuel supply amount from the low-pressure side supply line 9 to the high-pressure side supply lines 15 and 15 (high-pressure pump 7 And a flow rate control valve 16 for adjusting the fuel discharge amount).

  In the present embodiment, high-pressure fuel is supplied from the high-pressure pump 7 to the common rail 8 through a pair of high-pressure supply lines 15 and 15, but via a single high-pressure supply line. The high-pressure fuel may be supplied to the common rail 8.

  The common rail 8 is connected to the fuel injection valve 3 of each cylinder 4 via a high pressure side distribution supply line 17, and the high pressure fuel supplied from the high pressure pump 7 to the common rail 8 is distributed from the common rail 8 to the high pressure side distribution line. Each fuel injection valve 3 is supplied via a supply pipe 17. The common rail 8 is provided with a pressure control valve 18 for maintaining the rail pressure, which is the pressure of the fuel inside, at a predetermined pressure, and a pressure sensor 19 for detecting the rail pressure.

  The high-pressure pump 7, the common rail 8, and the fuel injection valve 3 are connected to the suction port side of the low-pressure pump 6 in the fuel tank 5 via return lines 20, 21, 22, respectively. 8 and surplus fuel or leaked fuel supplied to each of the fuel injection valves 3 recirculates to the fuel tank 5 through the return lines 20, 21, and 22.

  Further, in the present embodiment, a temperature sensor 23 as a fuel temperature detecting means for detecting the temperature of the fuel supplied to the fuel injection valve 3 is provided in an appropriate place in the fuel supply device 1, for example, the high pressure pump 7. Further, a control unit 30 that controls the operation of the fuel supply device 1 and the generator 13 is mounted on the vehicle.

  The control unit 30 is an electronic circuit unit including a microcomputer and the like, and has a function of controlling the operation of the low-pressure pump 6 through the inverter circuit 12, a function of controlling the operation of the generator 13 through the inverter circuit 14, It has a function of controlling the opening and closing of each fuel injection valve 3 and a function of controlling the fuel discharge amount of the high-pressure pump 7 via the flow control valve 16 of the high-pressure pump 7. In this case, the detection data of the pressure sensor 19 and the temperature sensor 23 are input to the control unit 30 for these control processes, and the rotation speed (rotation speed) of the internal combustion engine 2 is received from an appropriate sensor (not shown). Various detection data such as (speed), engine temperature (cooling water temperature), intake air temperature, vehicle traveling speed (vehicle speed), and the like are input. And the control unit 30 performs operation control of the fuel supply apparatus 1, the generator 13, etc. by performing the process of the program mounted previously using those input data.

  Supplementally, in this embodiment, the control unit 30 realizes the supply voltage adjusting means in the present invention by the function of controlling the operation of the generator 13.

  Next, the control process by the control unit 30 will be specifically described focusing on the control process related to the operation of the fuel supply device 1.

  During operation of the internal combustion engine 2, the control unit 30 supplies power for operation from the battery 11 to the low-pressure pump 6 via the inverter circuit 12 and operates the low-pressure pump 6 while operating the flow control valve 16 of the high-pressure pump 7. The fuel supplied to the common rail 8 from the fuel tank 5 via the low pressure pump 6 and the high pressure pump 7 is made high pressure. At the same time, the control unit 30 determines the required fuel injection amount (fuel injection amount command value) and the fuel injection timing by each fuel injection valve 3 according to the detection data of the operating state such as the rotational speed of the internal combustion engine 2. The valve opening time and valve opening timing of each fuel injection valve 3 are controlled in accordance with the determined required fuel injection amount and fuel injection timing. Thus, a required amount of high-pressure fuel suitable for the operating state of the internal combustion engine 1 is supplied to each cylinder 4 of the internal combustion engine 1 at a required timing, and the internal combustion engine 1 is operated.

  The control unit 30 controls the operation of the generator 13 while operating the fuel supply device 1 and operating the internal combustion engine 2 in this way.

  In this case, basically, a normal operating state in which the rotational speed of the internal combustion engine 2, the electrical load of the battery 11 (the total amount of power consumption of the electrical load connected to the battery 11), etc. satisfy the predetermined conditions. Below, in order to charge the battery 11 or to suppress the power consumption of the battery 11, the control unit 30 causes the generator 13 to perform a power generation operation. On the other hand, the control unit 30 stops the power generation operation of the generator 13 in order to reduce the fuel consumption of the internal combustion engine 2 under a limited operation condition that satisfies the condition that the electrical load of the battery 11 is sufficiently small. .

  Here, in the state where the power generation operation of the generator 13 is stopped, as described above, the supply voltage to the low pressure pump 6 is lower than that during the power generation operation of the generator 13, so the fuel discharge amount (unit) of the low pressure pump 6 is The maximum amount of fuel that can be discharged per hour) is less than during the power generation operation of the generator 13.

  On the other hand, in a situation where the temperature of the fuel supplied to the fuel injection valve 3 is relatively high (for example, a high temperature of about 80 ° C.), the viscosity of the fuel is low, so the high pressure pump 7, common rail 8, fuel A fuel leak is likely to occur in the injection valve 3. In this case, even when the power generation operation of the generator 13 is stopped, in a situation where the required fuel injection amount of the fuel injection valve 3 is relatively small, even if the fuel leak occurs, a sufficient amount can be compensated for. It is possible to supply fuel to each fuel injection valve 3. However, in a situation where the required fuel injection amount of the fuel injection valve 3 is relatively large when the power generation operation of the generator 13 is stopped, the amount of fuel actually supplied to the fuel injection valve 3 is the required fuel injection amount. There is a risk of shortage.

  Graphs a and b shown in FIG. 2 compensate for the above-described fuel leak when the temperature of the fuel is relatively high (for example, about 80 ° C.) or relatively low (for example, about 40 ° C.). 6 is a graph illustrating the relationship between the discharge amount of the low-pressure pump 6 (necessary discharge amount per unit time) necessary for the operation and the rotational speed of the internal combustion engine 2. These graphs a and b are graphs when the load of the internal combustion engine 2 is high (when the required fuel injection amount is close to the maximum).

  As shown in the drawing, when the temperature of the fuel is high, there is more fuel leakage than when the temperature is low, and therefore the required discharge amount of the low-pressure pump 6 becomes large. Further, in a state where the power generation operation of the generator 13 is stopped (when the supply voltage to the low pressure pump 6 is low), the maximum amount of fuel that can be discharged from the low pressure pump 6 is the broken line in FIG. The line value Qmax_L shown in FIG. Therefore, when the temperature of the fuel is high, the low-pressure pump 6 can be used when the rotational speed of the internal combustion engine 2 is higher than NEa shown in FIG. The required discharge amount becomes higher than Qmax_L. For this reason, when the rotational speed of the internal combustion engine 2 is higher than NEa shown in FIG.

  Although not shown, in the power generation operation state of the generator 13 (when the supply voltage to the low-pressure pump 6 is high), the maximum amount of fuel that can be discharged from the low-pressure pump 6 is when the temperature of the fuel is high. Also, the value is larger than the required discharge amount of the low-pressure pump 6. Even when the temperature of the fuel is low, the required discharge amount of the low-pressure pump 6 becomes higher than Qmax_L when the rotation speed of the internal combustion engine 2 is the high-speed rotation speed (> NEa). However, in the present embodiment, as described later, when the rotational speed of the internal combustion engine 2 is higher than a predetermined value NE1, the generator 13 is caused to perform the power generation operation regardless of the temperature of the fuel.

  For this reason, in the present embodiment, the control unit 30 is configured such that when the fuel temperature is relatively high and the required fuel injection amount is relatively large (when the load on the internal combustion engine 2 is relatively large), The operation of the generator 13 is controlled so that the generator 13 can perform the power generation operation.

  More specifically, the operation control of the generator 13 by the control unit 30 is executed as shown in the flowcharts of FIGS. 3 and 4. FIG. 3 is a flowchart showing a control process of the control unit 30 in a stopped state of power generation operation of the generator 13 (hereinafter referred to as OFF state), and FIG. 4 is a power generation operation state of the generator 13 (hereinafter referred to as ON state). It is a flowchart which shows the control processing of the control unit 30 in FIG. The processes in these flowcharts are sequentially executed at a predetermined control processing cycle.

  Referring to FIG. 3, in the OFF state of generator 13, control unit 30 controls generator 13 from the OFF state to the ON state in STEP 7 when any one of STEPs 1 to 6 is satisfied. . That is, the fuel heater (not shown) for heating the fuel is ON (STEP 1), the rotational speed of the internal combustion engine 2 is higher than the predetermined value NE1 (STEP 2), and the vehicle speed is the predetermined value V1. Higher than that (STEP 3), the electrical load of the battery 11 (the total amount of power consumed by the electrical load connected to the battery 11) is larger than a predetermined value EL1 (STEP 4), and the required fuel of the fuel injection valve 3 The injection amount is smaller than the lower limit side predetermined value TL1 or larger than the upper limit side predetermined value TH1 (STEP 5), the temperature of the fuel (the temperature detected by the temperature sensor 23) is higher than the predetermined value FT1, In addition, any one of the conditions that the required fuel injection amount of the fuel injection valve 3 is larger than a predetermined value f1 (NE) determined according to the rotational speed of the internal combustion engine 2 (STEP 6) is satisfied. Case , The control unit 30 controls the ON state of the generator 13 from the OFF state. And when none of conditions of STEP1-6 are satisfied, the control unit 30 maintains the generator 13 in an OFF state. The predetermined value f1 (NE) in the condition of STEP 6 is a value (function value of the rotational speed) set according to the detected value of the rotational speed of the internal combustion engine 2, and the higher the rotational speed of the internal combustion engine 2, It is set based on a preset data table or arithmetic expression so as to be a large value.

  When the process of the flowchart of FIG. 3 changes from the state in which the condition of STEP 6 is not satisfied to the state in which the condition is satisfied, the generator 13 is controlled from the OFF state to the ON state. For this reason, when the temperature of the fuel is a high temperature (for example, 80 ° C.) and the required fuel injection amount is relatively large, the supply voltage to the low-pressure pump 6 is increased. The discharge amount can be increased. As a result, it is possible to prevent a situation in which the amount of fuel actually supplied to the fuel injection valve 3 is insufficient relative to the required fuel injection amount.

  Therefore, in the present embodiment, the supply voltage adjusting means in the present invention is realized by the determination process of STEP 6 and the process of STEP 7 in the control unit 30.

  On the other hand, referring to FIG. 4, in the ON state of the generator 13, the control unit 30 controls the generator 13 from the ON state to the OFF state in STEP 19 when all the determination conditions in STEP 11 to 18 are satisfied. To do. That is, the fuel heater (not shown) for heating the fuel is OFF (STEP 11), the rotational speed of the internal combustion engine 2 is lower than the predetermined value NE2 (STEP 12), and the vehicle speed is the predetermined value V2. The engine temperature (cooling water temperature of the internal combustion engine 2) is higher than the predetermined value TWX (STEP 14), the intake air temperature of the internal combustion engine 2 is higher than the predetermined value TAX (STEP 15), 11 is larger than the predetermined amount EL2 (STEP 16), the required fuel injection amount of the fuel injection valve 3 is larger than the lower limit side predetermined value TL2 and smaller than the upper limit side predetermined value TH2 (STEP 17), The fuel temperature (the temperature detected by the temperature sensor 23) is lower than the predetermined value FT2, or the required fuel injection amount of the fuel injection valve 3 is smaller than the predetermined value f2 (NE) (S EP18), if all conditions of the conditions is satisfied that the control unit 30 controls the OFF state of the generator 13 from the ON state. Then, if any one of STEPs 11 to 18 is not satisfied, the control unit 30 maintains the generator 13 in the ON state. The predetermined value f2 (NE) in the condition of STEP 18 is a value (function value of the rotational speed) set according to the detected value of the rotational speed of the internal combustion engine 2, and the higher the rotational speed of the internal combustion engine 2, the higher the value. It is set based on a preset data table or arithmetic expression so as to be a large value.

  Here, the predetermined value NE2 in STEP12, the predetermined value V2 in STEP13, the predetermined amount EL2 in STEP16, the lower limit side predetermined value TL2 and the upper limit side predetermined value TH2 in STEP17, and the predetermined values FT2 and f2 (NE) in STEP18 are respectively described above. 3, the predetermined value NE1 in STEP2, the predetermined value V1 in STEP3, the predetermined amount EL1 in STEP4, the lower limit side predetermined value TL1 in STEP5 and the upper limit side predetermined value TH1, and the same value as the predetermined values FT1, f1 (NE) in STEP6 It's okay. However, in order to prevent the hunting of switching between the ON state and the OFF state of the generator 13, the predetermined value in the flowchart of FIG. 4 and the predetermined value in the flowchart of FIG. 3 are slightly different from each other. It is preferable to set it to a value. Therefore, in this embodiment, the predetermined value NE2 in STEP12 is set to a value slightly smaller than the predetermined value NE1 in STEP2, the predetermined value V2 in STEP13 is set to a value slightly smaller than the predetermined value V1 in STEP3, and STEP16. The predetermined value EL2 at is set to a value slightly smaller than the predetermined value EL1 at STEP4. Further, the lower limit side predetermined value TL2 and the upper limit side predetermined value TH2 in STEP 17 are set to a value slightly larger than the lower limit side predetermined value TL1 and a value slightly smaller than the upper limit side predetermined value TH1, respectively. Further, the predetermined values FT2 and f2 (NE) in STEP18 are set to values slightly smaller than the predetermined value FT1 in STEP6 and slightly smaller than f1 (NE), respectively. Since f1 (NE) and f2 (NE) are values (function values of the rotational speed) corresponding to the rotational speed of the internal combustion engine 2, f2 (NE) is smaller than f1 (NE). This means that the value of f2 (NE) at each rotational speed is smaller than the value of f1 (NE).

  When the process of the flowchart of FIG. 4 is changed from a state where the condition of STEP 18 is not satisfied to a state where the condition is satisfied, the generator 13 is controlled from the ON state to the OFF state. Even in this state, when the required fuel injection amount of the fuel injection valve 3 decreases and the load on the internal combustion engine 2 decreases, the power generation operation of the generator 13 is stopped.

  According to the present embodiment described above, when the generator 13 is in the OFF state, the generator 13 is turned on when the fuel temperature becomes a high temperature and the required fuel injection amount is relatively large. Thus, the supply voltage to the low-pressure pump 6 is increased, and consequently the discharge amount of the low-pressure pump 6 is increased. Thereby, it is possible to prevent a situation in which the amount of fuel actually supplied to the fuel injection valve 3 is insufficient with respect to the required fuel injection amount due to fuel leakage.

  In addition, conditions other than the conditions of STEP6 and STEP18 regarding the switching of the operating state of the generator 13 are not limited to the conditions shown in the present embodiment, and various other conditions (for example, the remaining capacity of the battery 11). Conditions).

  In this embodiment, the supply voltage to the low-pressure pump 6 is increased by the power generation operation of the generator 13 and the discharge amount of the low-pressure pump 6 is increased. For example, from the battery 11 through the DC / DC converter. Thus, power may be supplied to the inverter circuit 12 on the low pressure pump 6 side, and the supply voltage to the low pressure pump 6 may be changed by the DC / DC converter.

1 is a diagram schematically showing a system configuration related to a fuel supply device according to an embodiment of the present invention. The graph which illustrates the relationship between the required discharge amount of the low voltage | pressure pump in embodiment, and the rotation speed of an internal combustion engine. The flowchart which shows the control processing of the control unit in embodiment. The flowchart which shows the control processing of the control unit in embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Fuel supply apparatus, 2 ... Internal combustion engine, 3 ... Fuel injection valve, 5 ... Fuel tank, 6 ... Low pressure pump (1st pump), 7 ... High pressure pump (2nd pump), 11 ... Power storage device, 13 ... Generator, 30 ... control unit, STEP6, 7 ... supply voltage adjusting means.

Claims (2)

A first fuel pump that sucks and discharges fuel in the fuel tank; and a second fuel pump that boosts the fuel discharged from the first fuel pump and supplies the boosted fuel to a fuel injection valve of the internal combustion engine. In the fuel supply device
The first fuel pump is constituted by an electric pump in which the discharge amount increases as the supply voltage is higher,
Fuel temperature detection means for detecting the temperature of the fuel;
It is determined whether or not a condition that the temperature detected by the fuel temperature detecting means is equal to or higher than a predetermined temperature and the required fuel injection amount of the fuel injection valve is equal to or higher than a predetermined amount is satisfied. And a supply voltage adjusting means for making the supply voltage of the first fuel pump higher than when the condition is not satisfied.   2. The fuel supply device according to claim 1, wherein the first fuel pump includes a power storage unit, a power generation operation capable of charging the power storage unit, and generating a higher output voltage than the power storage unit during the power generation operation. Is connected to the capacitor and the generator so as to receive the supply voltage from the generator, and the supply voltage adjusting means performs the generator operation of the generator when the condition is satisfied when the generator operation of the generator is stopped. A fuel supply apparatus, characterized in that, by performing, the supply voltage of the first fuel pump is higher than when the condition is not satisfied.

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