JPH0781542B2 - Fuel injector - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection device for injecting fuel into, for example, an automobile engine, and particularly to a fuel injection device capable of optimally controlling a voltage applied to a fuel pump. Regarding the device.

[Conventional technology]

First, FIG. 5 shows a fuel injection device including a conventional fuel pump.

In the figure, reference numeral 1 is an automobile engine, and the engine 1 is composed of a cylinder 1A, a piston 1B, a fuel chamber 1C, etc., and the engine 1 is provided with an injection valve 2 for injecting fuel into the fuel chamber 1C. At the same time, an intake manifold 3 for intake of outside air is provided in the fuel chamber 1C, and a throttle valve 4 is provided in the middle of the intake manifold 3.

Reference numeral 5 denotes a fuel tank for storing the fuel 6, and 7 denotes a roller vane type fuel pump provided in the fuel tank 5. The fuel pump 7 serves as a casing 7A and a motor portion provided in the casing 7A. DC motor section 7B, pump section 7C rotatably driven by the DC motor section 7B, suction port 7D and discharge port 7E provided on the upper and lower end sides of casing 7A.
It is composed of and. A fuel pipe 8 connects between the fuel pump 7 and the injection valve 2, and a filter 9 and a pressure regulator 10 are provided in the fuel pipe 8. The pressure regulator 10 guides a positive pressure or a negative pressure in the collector 3A of the intake manifold 3 as a control pressure via a control pressure pipe 11, and controls the fuel pressure according to the pressure in the intake manifold 3 so that excess oil Is returned to the fuel tank 5 via the return pipe 12.

Reference numeral 13 is a canister having a built-in activated carbon that temporarily absorbs evaporative gas as vapor generated by vaporization of the fuel 6, and the inflow side of the canister 13 has an inflow pipe 14 and a check valve.
It is connected to the inside of the fuel tank 5 via 15. here,
The check valve 15 allows the vapor from the fuel tank 5 to flow toward the canister 13 side and prevents a backflow from the canister 13 side. Further, the canister 13 is provided with a purge control valve 13A, and the purge control valve 13A stores in the canister 13 and a back pressure introducing pipe 16 that guides the pressure in the intake manifold 3 near the throttle valve 4 as a back pressure. The evaporative gas is connected to an outflow pipe 17 for purging (discharging) the evaporative gas to the collector 3A at a position downstream of the throttle valve 4 in the intake manifold 3. Then, the canister 13 allows the evaporative gas generated in the fuel tank 5 to flow in through the inflow pipe 14 and the check valve 15 and temporarily stores it in the built-in activated carbon. On the other hand, the purge control valve 13A is opened by introducing a negative pressure generated in the intake manifold 3 through the back pressure introducing pipe 16 at the time of off-idling when the throttle valve 4 starts to open, and stored in the canister 13. The evaporative gas is purged as purge air from the outflow pipe 17 into the intake manifold 3 and is used as a part of fuel.

Next, a fuel pump control device is shown in FIG. 6 and explained.

In the figure, 18 is a DC power source consisting of a battery power source, and the DC power source 18 is connected to a high voltage terminal of a DC motor section 7B of the fuel pump 7. The ground terminal of the DC motor unit 7B is connected to the voltage control transistor 19 such as a Darlington connection or a power transistor, and the resistor 20 for current detection or overcurrent prevention, and is grounded.

Reference numeral 21 denotes a control unit as an applied voltage control means composed of a microcomputer including a CPU, ROM, RAM, etc., and the control unit 21 is the injection valve 2
Has a function as an injection amount calculation device for controlling the fuel injection amount and a function as an applied voltage control device for controlling the fuel pump 7. The output side is connected to a transistor 19 via a transistor control circuit 29 described later, and a voltage control signal Output to the transistor control circuit 29, and the transistor 19 causes the DC motor unit to
The voltage applied to 7B is controlled.

As shown in FIG. 7, the control unit 21 comprises an input / output control circuit 22, a processing circuit 23, and a memory circuit 24. The input side of the input / output control circuit 22 has an engine switch 25 and an air flow meter. 26, crank angle sensor 27 and idle switch attached to throttle valve 4
28 and the like are connected, and the injection valve 2 and the transistor control circuit 29 and the like are connected to the output side. In addition, the memory circuit 24
A program (not shown) for performing injection amount control processing, applied voltage control processing, and the like based on the arithmetic expressions (1), (2), and (3) described later is stored therein.

That is, the control unit 21 determines the injection amount T _i from the injection valve 2 as T _i = T _p × α × α ′ × C _o + T _s (1) where T _p : basic injection amount α: air-fuel ratio feedback Correction coefficient α ′: basic air-fuel ratio learning correction coefficient C _O : various correction coefficients T _s : voltage correction coefficient, and an injection pulse signal having a predetermined duty based on this calculation is output to the injection valve 2 The desired fuel is injected into the fuel chamber 1C from No.2.

Further, the control unit 21 controls the voltage F _pv applied to the fuel pump 7 during normal traveling of the vehicle, However, A: constant B: minimum voltage (for example, 8.5 V) T _i : injection amount N: engine speed is calculated, and this applied voltage F _PV is applied from the voltage control transistor 19 to the DC motor unit 7B. It outputs a voltage control signal to the transistor control circuit 29. Then, the control unit 21 controls the applied voltage F _PV so as to be appropriately raised or lowered between a minimum voltage of about 8.5 V and a maximum voltage of about 14 V according to the operating conditions of the vehicle, and the fuel pump 7 The applied voltage F _PV is applied to the DC motor unit 7B of.

In this case, when the engine switch 25 is turned on, the control unit 21 controls the idle switch 28 during idling.
Is ON, the applied voltage F to the fuel pump 7
_{When pv is set} to a low voltage of, for example, about 8.5V according to the equation (2), and the idle switch 28 is turned off during the off-idle, the applied voltage F _pv is calculated by the first term of the equation (2), and for example, 14V. The pressure is increased to some extent, and the amount of fuel discharged from the fuel pump 7 is increased.

In addition, when the idle switch 28 is switched from the ON state to the OFF state, the control unit 21 responds to the start signal of the vehicle by the OFF signal from the idle switch 28. Of the _o, the post-idle increase correction coefficient (K _AI ) is temporarily increased to increase the injection amount T _i so that the vehicle starts smoothly. The various correction coefficients C _o are the sum of various increase correction coefficients including the water temperature increase correction coefficient (K _TW ), the post-start increase correction coefficient (K _AS ), and the post-idle increase correction coefficient (K _AI ). Further, the basic injection amount T _P is based on the intake air amount Q by the air flow meter 26 and the engine speed N by the crank angle sensor 27. (K is a constant) is calculated.

The fuel injection device including the fuel pump control device according to the prior art has the above-described configuration, and its operation will be described below.

First, when the engine starts, the fuel pump 7 rotates,
The fuel 6 in the fuel tank 5 is discharged into the fuel arrangement pipe 8,
This fuel 6 is supplied to the control unit 21 from the injection valve 2 provided at the tip side of each branch pipe 3B of the intake manifold 3.
The fuel is injected into the fuel chamber 1C of the engine 1 based on the injection amount T _i of. At this time, the fuel pressure of the fuel 6 in the fuel pipe 8 is adjusted by the pressure regulator 10, and the surplus oil is sequentially returned to the return pipe.
It is returned to the inside of the fuel tank 5 via 12. Then, the fuel 6 injected from the injection valve 2 is sucked into the fuel chamber 1C while being mixed with the intake air sucked into the intake manifold 3 as the piston 1B reciprocates, and becomes exhaust gas after combustion. The exhaust air is exhausted from an exhaust manifold (not shown).

Further, when the vehicle is idle, the idle switch 28 is in the ON state, and the applied voltage F _PV to the DC motor section 7B of the fuel pump 7 is about 8.5 V, while the idle switch 28 is OFF when the vehicle starts. As a result, the applied voltage F _PV to the fuel pump 7 is boosted to about 14 V, the pump portion 7C of the fuel pump 7 is rotated at high speed to increase the fuel discharge amount, and each of the equations (1) is used. Of the correction coefficient C _o ,
The increase correction coefficient (K _AI ) after idling becomes large, and the injection valve 2
The injection amount T _{i from} is increased, and the increased fuel is injected.

[Problems to be Solved by the Invention]

By the way, in the above-described conventional technique, when the roller vane type fuel pump 7 is used to increase the discharge amount of fuel, erosion (erosion) due to cavitation occurs in the pump portion 7C, and the pump portion 7C is There are many problems of damage. Therefore, as a result of trying the erosion generation experiment by the cavitation generated in the pump portion 7C of the roller vane type fuel pump 7, the applicant has found that the cavitation generation in the pump portion 7C causes the new fuel 6 to be stored in the fuel tank 5. It has been found that a large amount occurs after refueling.

That is, the results of the experiment conducted with the fuel tank 5 filled with about 50 new fuels 6 will be described with reference to FIGS. 8 and 9.

First, in a state in which the engine 1 is continuously driven, the fuel 6 in the fuel tank 5 is discharged into the fuel pipe 8 by the fuel pump 7, and is fed into the fuel tank 5 from the return pipe 12 via the pressure regulator 10. It has been returned. By repeating this, the fuel 6 is warmed by the heat from the engine 1, so the fuel temperature rises with the passage of time as shown in FIG. 8, and this fuel temperature rises to about 50 degrees or more after about 5 hours. To rise.

Further, generally, the fuel pump 7 is designed to discharge a predetermined amount (for example, about 200) of the fuel 6 per unit time. However, when refueling a new fuel 6 and continuously driving the engine 1, the discharge amount of the fuel 6 from the fuel pump 7 changes as shown in FIG.
It was found that it takes about 18 hours to restore the discharge amount to the predetermined amount. This decrease in the discharge amount promotes the generation of vapor by the volatile components due to the new fuel 6 in the fuel tank 5, so that cavitation occurs in the pump portion 7C of the fuel pump 7 and the cavitation occurs in a state close to the cavitation lock. Fuel 6
Is being discharged.

As a result, about 5 hours after refueling with new fuel 6,
Volatile components evaporate from the refueled new fuel 6, and as the fuel temperature gradually rises, the discharge amount of the fuel 6 from the fuel pump 7 significantly decreases, and the desired fuel 6 for the engine 1 is obtained. Is no longer supplied, and there is a problem in that the engine 1 does not rotate properly and output is insufficient.

Further, in the prior art, the pump portion 7C is rotating at a high rotation speed so that the fuel pump 7 always discharges a predetermined discharge amount 200 even after refueling with new fuel 6. Therefore, while the fuel 6 is warmed and the fuel 6 in the fuel tank 5 is agitated by the fuel pump 7 to generate vapor due to volatile components, the vapor causes cavitation in the pump portion 7C, and the cavitation occurs. Results in erosion in the pump portion 7C, which causes a problem of damaging the pump portion 7C of the fuel pump 7.

The present invention has been made in view of the above-mentioned various problems of the prior art. In the present invention, the amount of vapor flowing from the fuel tank toward the canister becomes smaller than a predetermined amount due to the volatile components of the new fuel after refueling. Until then, by reducing the applied voltage applied to the motor part of the fuel pump by a predetermined voltage, it is possible to reduce the occurrence of cavitation in the fuel pump and effectively prevent damage to the pump part. An object is to provide a control device.

[Means for Solving the Problems]

In order to solve the above-mentioned problems, the feature of the configuration adopted by the present invention is that a check valve is provided, and based on a signal from the valve opening detection means for detecting opening of the check valve, and a signal from the valve opening detection means. , A vapor amount determining means for determining whether or not the vapor amount flowing from the fuel tank toward the canister exceeds a predetermined amount within a fixed time, and the vapor amount determining means determines that the vapor amount exceeds the predetermined amount. At this time, there is provided an applied voltage lowering means for lowering the voltage applied from the applied voltage control means to the motor portion of the fuel pump by a predetermined voltage.

[Action]

With the above configuration, the applied voltage applied to the motor section of the fuel pump is set to a low voltage until the amount of vapor flowing from the fuel tank toward the canister becomes smaller than a predetermined amount due to the volatile component of the fresh fuel after refueling. It is possible to reduce the number of rotations of the motor unit by applying the voltage, to lower the rotation of the pump unit, and to reduce the occurrence of vapor and cavitation in the pump unit.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 4. In the embodiments, the same components as those of the above-described conventional technique are designated by the same reference numerals, and the description thereof will be omitted.

In the figure, 31 is a check valve which is located between the fuel tank 5 and the canister 13 and is provided in the middle of the inflow pipe 14.
The check valve 31 has an inlet 32A on the peripheral wall and an inlet 32B on the bottom.
And a valve casing 32 formed in a bottomed tubular shape, a cover 33 for covering the upper end side of the valve casing 32, and the cover
A diaphragm 35 that is provided between the valve casing 32 and the valve casing 32 and that defines the vapor chamber 34, a valve body 36 that is provided at the center of the diaphragm 35 and is made of a magnetic material, and the valve body 36 are separated from each other.
A valve seat 37 formed on the upper end side of the outlet 32B so as to be seated
And a spring 38 that constantly urges the valve element 36 toward the valve seat 37,
It is attached to the front end side of the cover 33 and is roughly composed of a detection coil 39 as a valve opening detection means for detecting the displacement of the valve body 36 when the valve body 36 opens or closes. The inlet 32A of the valve casing 32 is connected to the inflow pipe 14
Is connected to the fuel tank 5, and the outlet 32B is connected to the canister 13 via the inflow pipe 14. Further, the detection coil 39 is connected via a lead wire 40 to the input side of an input / output control circuit 42 of a control unit 41 described later.

In the check valve 31 thus configured, when the vapor from the fuel tank 5 flows into the vapor chamber 34 and the pressure (vapor pressure) in the vapor chamber 34 becomes higher than the urging force of the valve spring 38,
The valve body 36 is separated from the valve seat 37, and the vapor in the vapor chamber 34 flows out from the outflow port 32B toward the canister 13. At this time, the detection coil 39 detects the displacement of the valve body 36 by an electromagnetic induction action, and outputs the detection signal to the control unit 41 via the lead wire 40.

Reference numeral 41 denotes a control unit composed of a microcomputer including a CPU, ROM, RAM, etc., and the control unit 41 has substantially the same structure as the control unit 21 shown in the prior art.
Reference numeral 41 has a function as an injection amount calculation device for controlling the injection valve 2 and a function as an applied voltage control device for controlling the fuel pump 7.

As shown in FIG. 2, the control unit 41 is composed of an input / output control circuit 42, a processing circuit 43, and a memory circuit 44. The input side of the input / output control circuit 42 has an engine switch 25 and an air flow meter. 26, crank angle sensor 27,
The idle switch 28, the detection coil 39 of the check valve 31, the fuel temperature sensor 45 and the like are connected, and the injection valve 2 and the transistor control circuit 29 and the like are connected to the output side. Further, the processing program shown in FIGS. 3 and 4 is stored in the memory circuit 44, and a predetermined fuel temperature t _o (for example, 50 ° C.) and a timer T are stored in the memory area 44A of the memory circuit 44. the predetermined time T _o (e.g., 5 minutes), the counter C predetermined count numeric C _o (e.g., 30), a voltage drop value [Delta] V (e.g., 1.5
V) and the minimum voltage value B (for example, 8.5V) for performing normal applied voltage control are stored as set values. The processing program shown in FIG. 3 is a fuel pump control processing program, and the processing program shown in FIG. 4 is the minimum voltage for setting the minimum voltage B of the second term of the equation (2) as applied voltage lowering means. It is a setting processing program.

Then, the control unit 41 calculates the injection amount T _i by performing the calculation of the expressions (1) and (3) based on the input signal from each sensor, and outputs the injection pulse signal to the injection valve 2. In addition, the applied voltage F according to the equation (2)
The discharge amount of the fuel 6 from the fuel pump 7 is controlled by calculating _pv and outputting the applied voltage F _PV to the DC motor unit 7B of the fuel pump 7 through the transistor control circuit 29. .

The fuel injection device according to the present embodiment has the above-described configuration, and calculates the injection amount T _i and controls the fuel injection amount from the injection valve 2, and further calculates the applied voltage F _PV to calculate the fuel pump. The basic operation of controlling the applied voltage F _PV applied to the DC motor unit 7B of No. 7 is not different from that of the prior art, and therefore its explanation is omitted.

Therefore, the fuel pump control device by the control unit 41 will be described with reference to FIG.

This process is started by closing the engine switch 25, and in step 1, the minimum voltage setting process described later is performed to set the minimum voltage B, and the storage area 44A of the storage circuit 44 is set.
The lowest voltage B is stored therein. Then, in step 2, the applied voltage control process is performed as in the prior art, and
Calculate the applied voltage F _PV by calculating the formula, and apply this applied voltage F _pv
In order to adjust the discharge amount of the fuel pump 7, the DC motor unit 7B is rotated, and the process returns in step 3.

Next, the minimum voltage setting process by the control unit 41 will be described with reference to FIG.

First, in step 11, the fuel temperature t of the fuel 6 stored in the fuel tank 5 is read from the fuel temperature sensor 45, and in step 12, the fuel temperature t
Is equal to or higher than a predetermined fuel temperature t _o (for example, 50 ° C),
If “YES” is determined, the fuel 6 in the fuel tank 5
Since it is in a state where the vapor is easily generated, the process proceeds to step 13, and when the determination is "NO", the vapor is substantially not generated, and therefore the process returns to step 1.

Then, in step 13, the timer T is started and the counter C is reset, in step 14, the detection signal of opening / closing of the check valve 31 from the detection coil 39 is read, and in step 15, the check valve 31 is opened. If it is YES, the vapor generated in the fuel tank 5 opens the check valve 31 to open the canister.
Since it is being distributed to the 13th side, the process moves to step 16 and the counter C is incremented by "1" with C = C + 1. Next, at step 17, a predetermined time T _O (for example,
It is determined whether or not 5 minutes) have elapsed. If it is determined to be "YES", the process proceeds to step 18, and if it is determined to be "NO", the process returns to step 14 to continue the subsequent processes.

Then, in step 18, it is judged whether or not the count value of the counter C exceeds a predetermined count value _Co (for example, 30), and "YE
Check valve 31 within the predetermined time T _O if it is determined that S "
There repeated opening by the number of times exceeding the count value C _o, because a state in which a large amount of the vapor is flowing through an inlet pipe 14 into the canister 13, the vapor amount that has flowed into the canister 13 exceeds a predetermined amount Judgment, move to step 19, minimum voltage B
Is calculated as B = 8.5−ΔV (4), and the minimum voltage B is set to 7V by lowering the lowered voltage value ΔV as a predetermined voltage by 1.5C later. Then, in step 21, the lowest voltage B is stored in the memory circuit 44, and in step 22, the process returns.

On the other hand, if it is determined to be “NO” in step 18, it can be determined that the amount of vapor flowing into the canister 13 is less than or equal to a predetermined amount. Therefore, the process proceeds to step 20, the minimum voltage B is set to 8.5V, and the step 21 is performed. Then, the lowest voltage B is stored in the memory circuit 44, and the process returns at step 22.

Thus, according to the present embodiment, when the fuel tank 5 is filled with the new fuel 6, the volatile component of the fuel 6 promotes the generation of evaporative gas (paver), the check valve 31 is opened, and the canister is opened. Since this evaporative gas can be stored in 13, the fuel 6 containing a large amount of volatile components is stored in the fuel tank 5 by utilizing this, and it is confirmed that a large amount of evaporative gas is generated. Can be determined by detecting the valve opening time of the fuel tank 5
It is possible to detect with high accuracy whether or not a large amount of vapor as evaporative gas is generated from the fuel 6 inside. Then, the applied voltage F _pv applied to the DC motor section 7B of the fuel pump 7 is lowered by a predetermined voltage ΔV (for example, 1.5V), and the minimum voltage B is lowered to about 7V. The applied voltage F _PV can be adjusted between 7V and 12.5V, and the voltage applied to the DC motor section 7B of the fuel pump 7 can be effectively reduced, so that the new fuel 6 is supplied into the fuel tank 5,
When vapor is generated due to the volatile components, the pump portion 7C of the fuel pump 7 can be rotated at a relatively low rotational speed, and the occurrence of cavitation in the pump portion 7C can be effectively reduced. it can. As a result, it is possible to prevent the generation of erosion in the pump section 7C, and
The life of can be extended.

Further, as illustrated in FIG. 9, the discharge amount of fuel after refueling is
It is possible to prevent a significant decrease, and it is possible to eliminate the poor rotation and insufficient output of the engine 1.

In the above embodiment, in the program shown in FIG. 4, step 14 to step 18 show a concrete example of the vapor amount judging means which is a constituent feature of the present invention, and step 19 shows a concrete example of the applied voltage lowering means. Shows.

Further, in the above-described embodiment, the case where a large amount of air vapor gas (vapor) is stored in the canister 13 has been described as the case where the new fuel 6 is refueled, but the present invention is not limited to this, and the fuel tank is provided under the hot summer in the midsummer. 5 and the fuel 6 have been warmed, or the fuel temperature of the fuel 6 has become abnormally high due to the excess oil of the engine 1, and the vapor of the fuel 6 has flowed toward the canister 13 in excess of a predetermined amount within a certain time. If it is detected through the check valve 31, the same effect can be obtained by driving the fuel pump 7 by lowering the applied voltage by the minimum voltage setting process shown in FIG.

Further, although the fuel temperature sensor 45 is provided in the fuel tank 5 in the above embodiment, the present invention is not limited to this, and may be provided in the fuel in the fuel pipe 8 or the like.

On the other hand, although the roller vane type fuel pump has been described in the above embodiment, the present invention is not limited to this, and the use of a turbine type fuel pump can also suppress the generation of vapor and improve the fuel discharge performance. And the like.

Furthermore, in the above embodiment, the detection coil of the check valve 31 is used.
Although the valve opening is detected by 39, the present invention is not limited to this, and a micro switch is attached to the check valve 31,
The valve opening detection means may be configured by detecting the ON / OFF operation of the micro switch.

〔The invention's effect〕

As described in detail above, according to the present invention, the amount of vapor flowing from the fuel tank toward the canister exceeds a predetermined amount within a certain period of time based on the signal from the valve opening detection means for detecting the opening of the check valve. It is determined by the vapor amount determination means, and when the vapor amount determination means determines that the vapor exceeds the predetermined amount, the voltage applied to the motor portion of the fuel pump is reduced by the application voltage reduction device by the predetermined voltage. Since it is configured, after refueling with new fuel, or when the fuel temperature in the fuel tank abnormally rises and a large amount of vapor is generated in the fuel tank, the applied voltage is reduced by a predetermined voltage, By applying it to the motor portion of the fuel pump, the rotation speed of the fuel pump can be reduced, and the generation of vapor can be effectively suppressed. As a result, the occurrence of cavitation in the pump portion of the fuel pump can be reduced, the occurrence of erosion can be reliably prevented, and the life of the fuel pump can be extended. Furthermore, since it is possible to prevent a decrease in the amount of fuel discharged after refueling, it is possible to eliminate the engine rotation failure and insufficient output.

[Brief description of drawings]

1 to 4 show an embodiment of the present invention, FIG. 1 is a vertical sectional view of a fuel tank and a check valve, FIG. 2 is a control block diagram of a control unit, and FIG. 3 is a fuel pump control process. FIG. 4, FIG. 4 is a flowchart showing the minimum voltage setting process, and FIGS. 5 to 9 show the prior art.
FIG. 5 is a circuit configuration diagram of the fuel injection device, FIG. 6 is a circuit configuration diagram of the fuel pump control device, FIG. 7 is a control block diagram of the control unit, and FIG. 8 is a change in fuel temperature with respect to elapsed time after refueling. FIG. 9 is a characteristic diagram showing the discharge amount of the fuel pump with respect to the elapsed time after the supply of new fuel. 1 ... Engine, 2 ... Injection valve, 5 ... Fuel tank, 6
...... Fuel, 7 ...... Fuel pump, 7B ...... DC motor section (motor section), 7C ...... Pump section, 13 ...... Canister, 31 ......
Check valve, 39 ... Detection coil (valve opening detection means), 41 ...
…control unit.

Claims (1)

[Claims] 1. A fuel tank for storing fuel, a fuel pump provided in the fuel tank, having a motor section and a pump section rotatably driven by the motor section, and fuel supplied from the fuel pump to an automobile. The injection valve for injecting into the engine, the canister for purging the fuel vapor generated in the fuel tank into the intake manifold, and the canister provided between the canister and the fuel tank. Allow distribution,
In a fuel injection device comprising a check valve for blocking a reverse flow and an applied voltage control means for applying a voltage to the motor section of the fuel pump, the check valve is provided,
Whether or not the amount of vapor flowing from the fuel tank toward the canister exceeds a predetermined amount within a certain period of time based on a signal from the valve opening detection means for detecting the opening of the check valve and the valve opening detection means. And a vapor amount determination means for determining whether the vapor amount exceeds a predetermined amount, the voltage applied from the applied voltage control means to the motor section of the fuel pump is reduced by a predetermined voltage. A fuel injection device, comprising: an applied voltage lowering unit for controlling the applied voltage.