JP3114530B2 - Fuel supply device for internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel supply device for an internal combustion engine, and more particularly to a fuel supply device for an internal combustion engine that can prevent the occurrence of vapor lock when the internal combustion engine is restarted when the temperature of the internal combustion engine is high.

[0002]

2. Description of the Related Art FIG. 7 shows the structure of a conventional fuel supply system for an internal combustion engine. In FIG. 7, 1 is a fuel tank, 2 is a pressure regulator, 4 is a fuel pump, 5
Is a fuel filter, 6 is a fuel supply passage, 7 is a delivery pipe, 8 is a fuel injection valve, 10 is an ECU (engine control unit), 30 is an internal combustion engine, 31 is an intake passage, 32 is an exhaust passage, and 33 is a cylinder. A body, 34 is a piston, 35 is a surge tank, 36 is a cold start injection valve, 37 is a water temperature sensor, and 38 is an air-fuel ratio sensor. Injection is performed from a cold start injection valve 36 provided in the surge tank 35 when the engine 30 is cold started, and each fuel injection valve 8 provided in the intake passage 31 is provided.
From the EC based on the detection value of the operating state parameter of the engine 30 by the water temperature sensor 37, the air-fuel ratio sensor 38, and the like.
The fuel injection amount calculated in U10 is injected.

The fuel pumped up from the fuel tank 1 by the fuel pump 4 is filtered by a fuel filter 5 and then supplied to a delivery pipe 7 through a fuel supply passage 6, from which the fuel injection valve 8 and the cold start injection are provided. It is sent to the valve 36. The pressure of the fuel in the delivery pipe 7 is kept constant by the pressure regulator 2 so that the fuel is injected with a predetermined injection pressure from the fuel injection valve 8 with respect to the intake pressure.

The pressure regulator 2 has a fuel chamber 21 inside a housing 20 formed by a diaphragm 23.
And the back pressure chamber 22, and the fuel chamber 2
1 is provided with a fuel inlet 26 and a fuel outlet 27. A valve 24 is attached to the fuel chamber 21 side of the diaphragm 23, and a spring 25 for biasing the diaphragm 23 toward the fuel chamber 21 is provided in the back pressure chamber 22. In general, the intake pressure in the intake passage 31 of the internal combustion engine 30 is introduced into the back pressure chamber 22 through the pressure introduction port 28. When the pressure of the fuel in the fuel chamber 21 is low, the valve 24 always closes the fuel outlet 27 in the fuel chamber 21 by the urging force of the spring 25. On the other hand, when the pressure in the fuel chamber 21 exceeds the set pressure of the spring 25, the diaphragm 23 moves toward the back pressure chamber 22 against the spring 25, and the valve 24
7, the fuel in the fuel chamber 21 is returned to the fuel tank 1 through the fuel return passage 29. As a result, the fuel pressure in the delivery pipe 7 is maintained at the difference between the set pressure of the spring 25 and the intake pressure. That is, the intake pressure in the intake passage 31 is introduced into the back pressure chamber 22, and the valve opening pressure of the valve 24 changes according to the magnitude of the intake pressure. The injection pressure is controlled to be constant with respect to the intake pressure.

When the internal combustion engine is stopped after a normal running of the vehicle and stopped for a while, the heat of the internal combustion engine generated during the running is transmitted to the fuel system while the vehicle is stopped, and the temperature of the fuel supply device of the internal combustion engine is reduced. And fuel vapor is likely to be generated. When restarting the internal combustion engine in such a state, vapor lock is likely to occur in the fuel supply device. In particular, when the vehicle stops at a high altitude after traveling, fuel vapor is more likely to be generated due to the low atmospheric pressure, and starting failure due to vapor lock is likely to occur.

[0006] In order to prevent such a vapor lock at the time of restarting at a high altitude and high temperature, an internal combustion such as returning the surplus fuel from the pressure regulator 2 installed at the end of the delivery pipe 7 to the fuel tank 1 as shown in FIG. In the fuel supply device of the engine, a high temperature restart is detected by a fuel temperature sensor. At the high temperature restart, the passage between the delivery pipe 7 and the pressure regulator 2 is closed to increase the fuel pressure, thereby stopping the vehicle. There has been proposed an apparatus for improving high-temperature startability by crushing vapor generated therein (see Japanese Utility Model Laid-Open No. 63-174568).

[0007]

However, in the prior art described in Japanese Utility Model Application Laid-Open No. Sho 63-174568, in addition to the pressure regulator, a durable and expensive device for increasing the fuel pressure in the delivery pipe and its device space,
Further, there is a problem that the control device is required, and the cost of the fuel supply device for the internal combustion engine is increased.

Accordingly, the present invention provides a fuel supply device for an internal combustion engine which can prevent a start failure due to a vapor lock at the time of high temperature restart with a device having a simple structure without occupying extra space in an engine room. The purpose is to provide.

[0009]

According to a first aspect of the present invention, there is provided a fuel supply passage communicating between a delivery pipe for supplying fuel to a fuel injection valve and a fuel tank. A pressure regulator is provided which opens when the pressure difference with the chamber becomes equal to or greater than a set value, and the pressure regulator returns excess fuel to the fuel tank and maintains a constant fuel injection pressure with respect to the atmospheric pressure. in the fuel supply system for the internal combustion engine formed in the fuel tank constitute a fuel tank of the closed, the pressure of the sealed fuel tank, so as to introduce into the back pressure chamber of the pressure regulator, further Puresshi
The pressure in the closed fuel tank is
To switch between pressure and atmospheric pressure outside the fuel tank
Whether the pressure switching means and the temperature of the internal combustion engine are high or higher than a predetermined value
High temperature determining means for determining whether or not the internal combustion engine is restarted;
Restart detection means for detecting whether or not
Is restarted at less than the specified value,
When switching to atmospheric pressure and the internal combustion engine is restarted at high temperature
Switch the introduction pressure switching means to the fuel tank pressure side
And control means for controlling the
I have.

[0010]

[0011] At this time, the shift detecting means for detecting a deviation from the reference state of the medium in the fuel tank, the injection time of the fuel injected from the fuel injection valve based on the deviation detected Correction means for correcting may be provided .

[0012]

According to the fuel supply apparatus of the action present onset light of the internal combustion engine, when the internal combustion engine is restarted at a high temperature, the pressure of the gas in the high closed fuel tank of pressure to the back pressure chamber of the pressure regulator is applied Therefore, the valve opening pressure of the pressure regulator increases, and the fuel pressure in the delivery pipe is increased, so that vapor lock at the time of high temperature restart is prevented. Further, since the back pressure chamber of the pressure regulator is switched to the atmospheric pressure side during the steady operation of the internal combustion engine, the fuel pressure during the steady operation can be kept constant, and the fuel injection can be performed with high accuracy.

[0013] Then, the pressure of the gas in the consistently high closed fuel tank of the pressure in the back pressure chamber of the pressure regulator is applied, the fuel pressure in Deriparipaipu always high, and vapor lock during hot restart prevention Is done. Also, during steady operation, the fuel pressure in the closed fuel tank is estimated or detected, and the fuel injection time is corrected to the fuel injection time according to the fuel pressure. Proper fuel injection is performed.

[0014]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1A shows a configuration of a first embodiment of a fuel supply device for an internal combustion engine of the present invention, and FIG. 1B shows an example of a configuration of the pressure regulator of FIG. 1A. It is. In the first embodiment, FIG.
The same constituent members as those of the conventional fuel supply device for an internal combustion engine described above will be described with the same reference numerals. Therefore, in FIG. 1 (a), 1 is a fuel tank, 2 is a pressure regulator, 3 is a suction filter, 4 is a fuel pump,
Reference numeral 5 denotes a fuel filter, 6 denotes a fuel supply passage, 7 denotes a delivery pipe, 8 denotes a fuel injection valve, and 10 denotes an ECU (engine control unit). In this embodiment, the illustration of the internal combustion engine is omitted.

In this embodiment, the fuel tank 1 is a sealed fuel tank, and a fuel filter 5 is provided in the sealed fuel tank. The pressure regulator 2 is not provided at the end of the delivery pipe 7, but is provided in the closed fuel tank 1 like the fuel filter 5. A fuel supply passage 6 on the discharge side of the fuel filter 5 is branched and connected to a fuel inlet 26 of the pressure regulator 2, and a fuel outlet 27 opens into the fuel tank 1. On the other hand, the pressure introduction port 28 of the pressure regulator 2 is connected with electromagnetic three-way switching valve 9 is introduced pressure switching means, among the remaining one of the connection opening sealed fuel tank 1 of the electromagnetic three-way valve 9 The other is open to the atmosphere outside the closed fuel tank 1 or the intake passage. The three-way solenoid switching valve 9 is switched by a signal from ECU 10, the pressure introducing port 28 of the pressure regulator 2,
It is connected to the inside of the closed fuel tank 1 or connected to the outside of the closed fuel tank 1. Further, the atmospheric pressure Pa, the water temperature Tw, the intake air temperature Ta, and the like detected by a sensor (not shown) are input to the ECU 10.

In the fuel supply device for an internal combustion engine configured as described above, the fuel sucked up by the fuel pump 4 from the fuel tank 1 through the suction filter 3 is filtered by the fuel filter 5 and then filtered by the fuel supply passage 6. The fuel is supplied to the pressure regulator 2 and the delivery pipe 7 through the passage, and the fuel whose pressure is adjusted by the pressure regulator 2 is injected from the fuel injection valve 8 through the delivery pipe 7.

The pressure regulator 2 used in this embodiment may be the same as the conventional one. The interior of the housing 20 is partitioned by a diaphragm 23 into two chambers, a fuel chamber 21 and a back pressure chamber 22. 21
Is provided with a fuel inlet 26 and a fuel outlet 27. A valve 24 is attached to the fuel chamber 21 side of the diaphragm 23, and a spring 25 for biasing the diaphragm 23 toward the fuel chamber 21 is provided in the back pressure chamber 22. In this embodiment, the intake pressure in the intake passage 31 of the internal combustion engine 30 or the internal pressure in the closed fuel tank 1 is introduced into the back pressure chamber 22 through the pressure introduction port 28 in this embodiment.

When the fuel pressure in the fuel chamber 21 is low,
The valve 24 normally closes the fuel outlet 27 in the fuel chamber 21 by the urging force of the spring 25. On the other hand, when the pressure in the fuel chamber 21 exceeds the set pressure of the spring 25,
The diaphragm 23 is opposed to the back pressure chamber 22 against the spring 25.
Move to the side, the valve 24 opens the fuel outlet 27, fuel within the fuel chamber 21 is returned to the fuel tank 1. As a result, the fuel pressure in the delivery pipe 7 is maintained at the difference between the set pressure of the spring 25 and the pressure in the back pressure chamber 22.

Therefore, in this embodiment, when the intake pressure in the intake passage 31 is introduced into the back pressure chamber 22, the pressure of the fuel in the delivery pipe 7 becomes a constant injection pressure with respect to the intake pressure. So that the fuel tank 1
When the internal pressure in the fuel tank 1 is introduced, the injection pressure is controlled to a high injection pressure according to the value of the internal pressure in the fuel tank 1 (generally larger than the absolute value of the atmospheric pressure).

FIG. 2 shows an electromagnetic three-way switching valve for switching the internal pressure of the fuel tank 1 and the atmospheric pressure (intake pressure) into the back pressure chamber 22 of the pressure regulator (P / R) 2 shown in FIG. 9 is a flowchart illustrating the operation of FIG. First,
In step 201, as the operating state parameter of the engine,
Atmospheric pressure Pa, water temperature Tw, intake air temperature Ta, and the like are read, and it is determined in subsequent steps 202 and 203 whether the engine is at a high temperature. The determination of the engine high temperature includes determining whether the water temperature Tw is higher than the reference value TW1 in step 202, and determining whether the intake air temperature Ta in step 203 is higher than the reference value
The determination is made based on whether it is higher. Then, in Step 202 and Step 203, Tw> TW1 and T
If a> TA1, it is determined that the temperature of the engine is high, and the routine proceeds to step 208, where the electromagnetic three-way switching valve 9 is switched to the black-black side to introduce the internal pressure in the fuel tank 1 into the back pressure chamber 22 of the pressure regulator 2. I do. In Steps 202 and 203, if Tw ≦ TW1 or Ta ≦ TA1, it is determined that the engine is not at a high temperature, and the routine proceeds to Step 204.

Steps 204 to 206 are for determining a high altitude high temperature condition. In this determination, first, at step 204, it is determined whether or not the atmospheric pressure Pa is lower than the reference value Po, and then, at step 205, it is determined whether or not the water temperature Tw is higher than the reference value TW2 (<TW1). ,
In step 206, the intake air temperature Ta is set to the reference value TA2 (<TA
It is performed by determining whether or not it is larger than 1). Then, Pa <Po and Tw> TW2 and Ta> T
In the case of A2, it is determined that the temperature of the engine is high at high altitude, and the routine proceeds to step 208, where the electromagnetic three-way switching valve 9 is switched to the black-black side to introduce the internal pressure in the fuel tank 1 into the back pressure chamber 22 of the pressure regulator 2. I do. Step 204
In step 206, Pa ≧ Po or Tw ≦ T
If W2 or Ta ≦ TA2, it is determined that the engine is not hot at high altitude, and the routine proceeds to step 207. Step 20
At 7, the electromagnetic three-way switching valve 9 is switched to the white-white side to introduce atmospheric pressure (intake pressure) into the back pressure chamber 22 of the pressure regulator 2.

As described above, in the first embodiment described above, the atmospheric pressure (intake pressure) is usually introduced as the back pressure of the pressure regulator 2, and the water temperature Tw of the engine is set to the reference value TW.
At a high temperature higher than 1 and the intake air temperature Ta is higher than the reference value TA1, or at a high altitude where the atmospheric pressure Pa is lower than the reference value Po, the engine water temperature Tw is higher than the reference value TW2 (<TW1) and the intake air temperature Ta is higher than the reference value TA2. When the temperature is higher than (<TA1), the internal pressure in the closed fuel tank 1 is introduced as the back pressure of the pressure regulator 2 by the electromagnetic three-way switching valve 9, so that the fuel injection pressure is increased. Therefore, the fuel injection pressure is increased at the time of high temperature restart and at the time of high temperature start at high altitude, so that generation of vapor lock can be suppressed, and startability is improved.

Further, in the first embodiment, the electromagnetic three-way switching valve 9 only switches the back pressure, as compared with the conventional shut-off valve which shuts off the high-pressure fuel in the delivery pipe 7 to the pressure regulator 2. Therefore, the structure is simple, and in the prior art, the shut-off valve is arranged in the engine room of the vehicle, whereas in this embodiment, the pressure regulator 2 and the electromagnetic three-way switching valve 9 are arranged in the fuel tank 1. As a result, no extra space is required in the engine room of the vehicle.

FIG. 3A is a diagram showing the configuration of a second embodiment of the fuel supply device for an internal combustion engine according to the present invention.
The same components as those of the first embodiment shown in FIG. The second embodiment differs from the first embodiment in that the pressure inlet 28 of the pressure regulator 2 provided in the sealed fuel tank 1 is opened only in the fuel tank 1. The only difference is that a temperature sensor 11 for detecting the fuel temperature is provided in the fuel tank 1. Accordingly, in the second embodiment, the internal pressure in the fuel tank 1 higher than the atmospheric pressure (intake pressure) is always introduced into the back pressure chamber 22 of the pressure regulator 2, and the injection pressure of the fuel in the fuel tank 1 Fuel tank 1 depending on temperature
It increases when the internal pressure inside increases.

Therefore, in the second embodiment, the temperature Tf of the fuel in the fuel tank 1 is detected by the temperature sensor 11, and the pressure in the fuel tank 1 is estimated from the detected fuel temperature Tf. The fuel injection amount is corrected according to the pressure Pt. FIG. 3B is a characteristic diagram showing characteristics of the pressure Pt in the fuel tank 1 with respect to the fuel temperature Tf in the fuel tank 1. The pressure Pt in the fuel tank 1 is different from the fuel temperature Tf detected by the temperature sensor 11. It can be estimated from this characteristic diagram. This characteristic diagram is a map
What is necessary is just to store it in the memory in CU10.

FIG. 4 is a flowchart illustrating a procedure for correcting the fuel injection amount according to the pressure Pt in the fuel tank 1 estimated from the fuel temperature Tf detected in the second embodiment. First, at step 401, atmospheric pressure Pa, water temperature Tw, intake air temperature Ta, fuel temperature Tf, and the like are read as the operating state parameters of the engine. At next step 402, it is determined whether or not the engine is performing air-fuel ratio feedback. When the air-fuel ratio feedback is being performed, step 403 is executed.
To determine whether or not the engine is operating in a steady state, not in an accelerated or decelerated state.

When the engine is operating steadily during air-fuel ratio feedback, the average value FAFAV of the air-fuel ratio feedback correction coefficient FAF, which is always calculated by another routine (not shown), is read in step 404. Then, in the subsequent step 405, a learning value KPFG of the correction coefficient of the injection fuel pressure is calculated by the following equation: KPFG = FAFAV-1.0, and the routine proceeds to step 406.

On the other hand, when it is determined in step 402 that the engine is not executing the air-fuel ratio feedback control, and when it is determined in step 403 that the engine is not in the steady state, the process also proceeds to step 406. In step 406, the internal pressure Pt in the fuel tank 1 is estimated and calculated from the fuel temperature Tf in the fuel tank 1 from the characteristic diagram shown in FIG. Then, in step 407, the correction coefficient KPF of the pressure of the fuel to be injected changes the valve opening set pressure of the pressure regulator 2 by P
r, the intake pressure is Pa, and KPF = {Pr / (Pr + (Pt−Pa))} ^Ｐ.

Thereafter, at step 408, the fuel injection period based on the corrected fuel pressure is calculated by the following equation: TAU = TAUP × (KPF-KPFG). Here, TUP is the basic fuel injection pulse width, and TAU is the corrected injection pulse width. The fuel injection period is adjusted by the injection pulse width TAU, and the amount of fuel injected from the fuel injection valve 8 is controlled. The learning value KPFG of the fuel correction coefficient is for learning a change in the property of the fuel.

In the second embodiment, the internal pressure Pt of the fuel tank 1 is introduced into the back pressure chamber 22 of the pressure regulator 2, whereby the conventional intake pressure is introduced into the back pressure chamber 22 of the pressure regulator 2. The problem of controllability deterioration due to a response delay can be improved as compared with the fuel supply device of the above. Further, since the tank internal pressure Pt of the sealed fuel tank 1 is used as the back pressure of the pressure regulator 2, the absolute pressure of the fuel at the time of high-altitude high-temperature start can be secured without being affected by a decrease in the atmospheric pressure or the like. It is suppressed and the restartability is improved. In addition, the change in the internal pressure Pt of the fuel tank 1 is estimated by detecting the fuel temperature Tf, and the control of the air-fuel ratio can be ensured by correcting the fuel injection amount.

FIG. 5 is a block diagram showing the configuration of a third embodiment of the fuel supply device for an internal combustion engine according to the present invention. The first and second embodiments shown in FIGS. 1 (a) and 3 (a) are shown. The same components as those of the embodiment are denoted by the same reference numerals. The configuration of the third embodiment is almost the same as that of the second embodiment described above, except that the internal pressure Pt in the fuel tank 1 after the fuel temperature Tf is detected by the temperature sensor 11 in the second embodiment. In contrast, the embodiment of FIG. 3 differs from that of FIG. 3 only in that a pressure sensor 12 capable of detecting the internal pressure is provided in the fuel tank 1. Therefore, also in the third embodiment, the internal pressure in the fuel tank 1 higher than the atmospheric pressure (intake pressure) is always introduced into the back pressure chamber 22 of the pressure regulator 2, and the fuel injection pressure is set in the fuel tank 1. It increases when the internal pressure in the fuel tank 1 increases due to the temperature.

In the third embodiment, the pressure in the fuel tank 1 is directly detected by the pressure sensor 12, and the fuel injection amount is corrected according to the detected fuel tank pressure Pt. FIG. 6 is a flowchart illustrating a procedure for correcting the fuel injection amount according to the pressure Pt in the fuel tank 1 detected in the third embodiment.

First, in step 601, the internal pressure Pt of the fuel tank 1 is read. In the following step 602, the correction coefficient KPF of the pressure of the fuel to be injected is determined by setting the valve opening set pressure of the pressure regulator 2 to Pr and the intake pressure to Pa.
It is calculated by the formula, KPF = {Pr / (Pr + (Pt-Pa))} ^1/2 .

Thereafter, in step 603, the fuel injection period based on the corrected fuel pressure is calculated by the following equation: TAU = TAUP × KPF. Here, TUP is the basic fuel injection pulse width, and TAU is the corrected injection pulse width. The fuel injection period is adjusted by the injection pulse width TAU, and the amount of fuel injected from the fuel injection valve 8 is controlled.

Also in the third embodiment, the internal pressure Pt of the fuel tank 1 is introduced into the back pressure chamber 22 of the pressure regulator 2 so that the conventional intake pressure is introduced into the back pressure chamber 22 of the pressure regulator 2. The problem of controllability deterioration due to a response delay can be improved as compared with the fuel supply device of the above. Further, since the tank internal pressure Pt of the sealed fuel tank 1 is used as the back pressure of the pressure regulator 2, the absolute pressure of the fuel at the time of high-altitude high-temperature start can be secured without being affected by a decrease in the atmospheric pressure or the like. It is suppressed and the restartability is improved. Further, by directly detecting a change in the internal pressure Pt of the fuel tank 1 and correcting the fuel injection amount, the air-fuel ratio controllability can be ensured.

[0036]

As described above, according to the fuel supply device for an internal combustion engine of the present invention, the back pressure chamber of the pressure regulator is connected to the atmospheric pressure side during the steady operation of the internal combustion engine. The fuel pressure during steady operation can be kept constant, fuel injection can be performed accurately, and when the internal combustion engine is restarted at a high temperature, the back pressure chamber of the pressure regulator is connected to the closed fuel tank. Therefore, the valve opening pressure of the pressure regulator is increased, and the fuel pressure in the delivery pipe is increased, so that there is an effect that vapor lock at the time of high temperature restart is prevented.

The pressure of the gas in the sealed fuel tank, which is always high, is always applied to the back pressure chamber of the pressure regulator. During steady operation, the fuel pressure in the sealed fuel tank is estimated and the fuel injection is performed. Since the time is corrected and proper fuel injection is performed, and high-pressure fuel can be injected when the internal combustion engine is restarted at a high temperature, there is an effect that vapor lock at the time of restarting at a high temperature is prevented.

[Brief description of the drawings]

FIG. 1A shows a first embodiment of a fuel supply device for an internal combustion engine according to the present invention.
FIG. 2B is a configuration diagram showing the configuration of the embodiment, and FIG. 2B is a cross-sectional view showing an example of the configuration of the pressure regulator of FIG.

FIG. 2 is a flowchart for explaining the operation of an introduction pressure switching means for switching and introducing a fuel tank internal pressure and an atmospheric pressure into a back pressure chamber of the pressure regulator shown in FIG. 1 (a).

FIG. 3 (a) shows a second embodiment of the fuel supply system for an internal combustion engine according to the present invention.
FIG. 3B is a configuration diagram showing a configuration of the embodiment, and FIG. 4B is a characteristic diagram showing a characteristic of a pressure in a fuel tank with respect to a fuel temperature.

FIG. 4 is a flowchart showing a procedure for correcting a fuel injection amount according to the pressure in the fuel tank estimated in the embodiment of FIG. 3;

FIG. 5 is a configuration diagram showing a configuration of a third embodiment of a fuel supply device for an internal combustion engine of the present invention.

FIG. 6 is a flowchart showing a procedure for correcting a fuel injection amount according to the pressure in the fuel tank detected in the embodiment of FIG.

FIG. 7 is a configuration diagram illustrating the overall configuration of a conventional fuel supply device for an internal combustion engine.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Sealed fuel tank 2 ... Pressure regulator 4 ... Fuel pump 6 ... Fuel supply passage 7 ... Delivery pipe 8 ... Fuel injection valve 9 ... Three-way switching valve (introduction pressure switching means) 10 ... ECU 11 ... Temperature sensor 12 ... Pressure sensor DESCRIPTION OF SYMBOLS 21 ... Fuel chamber 22 ... Back pressure chamber 23 ... Diaphragm 24 ... Valve 25 ... Spring 26 ... Fuel inlet 27 ... Fuel outlet 28 ... Pressure introduction port 29 ... Fuel return passage

Claims (1)

(57) [Claims] 1. A fuel supply passage connecting a delivery pipe for supplying fuel to a fuel injection valve and a fuel tank is opened when a pressure difference between the pressure in the passage and a back pressure chamber becomes equal to or greater than a set value. In a fuel supply device for an internal combustion engine, a pressure regulator is provided, and excess fuel is returned to the fuel tank by the pressure regulator, and the fuel injection pressure with respect to the atmospheric pressure is kept constant. The pressure in the closed fuel tank is introduced into the back pressure chamber of the pressure regulator, and the pressure in the closed fuel tank is further introduced into the back pressure chamber of the pressure regulator.
Pressure inside the fuel tank and atmospheric pressure outside the fuel tank
Pressure switching means for switching and introducing the temperature and a high pressure for judging whether or not the temperature of the internal combustion engine is higher than a predetermined value.
Temperature determination means, and a restart detection means for detecting whether or not the internal combustion engine has been restarted.
And when the temperature of the internal combustion engine is restarted below the predetermined value,
The introduction pressure switching means is switched to the atmospheric pressure side, and the internal combustion engine
When the pressure is restarted at the high temperature, the introduction pressure switching means
Control to switch the pressure to the fuel tank pressure side
And a fuel supply device for an internal combustion engine.