JPH09250426A - Fuel injection controller for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten a fuel pressure rising time at the time of starting of an internal combustion engine with a simple structure in a fuel injection controller provided with a high pressure pump. SOLUTION: Fuel forcedly fed from a feed pump 2 is fed to pipelines 4, 5 under a predetermined feed pressure regulated by a pressure regulator 3, and is forcedly fed to a delivery pipe 9 via a high pressure pump 6 and an electromagnetic opening/closing valve 7 at the time of valve opening. The electromagnetic opening/closing valve 7 is controllably opened or closed by an ECU 12 in such a manner as to be opened at the time of starting of drive of the feed pump 2 while closed on the basis of a detection signal from a pressure sensor 10 for detecting that a fuel pressure inside the delivery pipe 9 reaches a feed pressure. When the fuel pressure inside the delivery pipe 9 is smaller than the feed pressure at the time of the starting of an engine, the fuel under the feed pressure is forcedly fed directly to the delivery pipe 9 through the pipeline 5 in which the electromagnetic opening/closing valve 7 is opened. Consequently, the fuel pressure is immediately increased up to the feed pressure even if the high pressure pump 6 is driven at a low speed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection device used in an internal combustion engine, and more particularly to a fuel injection control device for an internal combustion engine that rapidly increases the fuel pressure at the time of starting.

[0002]

2. Description of the Related Art In-cylinder fuel injection systems are known in which an injector (fuel injection valve) is provided for each cylinder in order to spray fuel directly into the cylinder of an internal combustion engine. In this type of fuel injection device, it is necessary to secure a sufficiently high injection fuel pressure so that the fuel can be sprayed into the cylinder in a sufficiently fine mist state. Therefore, the pressure is raised to a predetermined pressure (feed pressure) by the feed pump. The fuel is further boosted to a desired fuel pressure using a high pressure pump. The fuel whose pressure has been increased by the high-pressure pump is stored in a reservoir (accumulation chamber), and is injected into each cylinder from the reservoir via an injector (fuel injection valve). The volume of the reservoir is set to a certain level or more, and the pressure drop in the reservoir due to the injection is reduced to keep the injection pressure constant.

The high-pressure pump is operatively connected to the engine via a belt and a cam shaft, and is driven at a rotational speed synchronized with the engine. The amount of discharge by the plunger every one revolution of the high-pressure pump is considerably smaller than the large volume of the reservoir. Moreover, since the high-pressure pump rotates slowly in the cranking state when the engine is started, the amount of fuel pressure fed to the reservoir per unit time becomes considerably low. Therefore, for example, it takes a considerable time for the fuel in the reservoir whose pressure has dropped to around atmospheric pressure to be pressurized. In particular, air bubbles due to fuel vapor etc. are present in the fuel in the reservoir before the engine is started, and the fuel compression process is performed while crushing these bubbles, so it is necessary to fill the reservoir with fuel and complete compression. For example, it takes a few seconds.

In order to solve this problem, for example, Japanese Patent Laid-Open No. 5-321787 discloses a fuel injection device provided with an auxiliary pump in addition to the high pressure pump. According to this device, the fuel pressurized to a relatively low pressure by the feed pump is pumped to both the high pressure pump and the auxiliary pump. The auxiliary pump is configured by accommodating a piston having a large-diameter piston and a small-diameter piston integrally in a cylinder, and by moving the large-diameter piston by fuel pressure from the feed pump acting on the auxiliary pump at the time of engine start. The small-diameter piston moves in the small-diameter cylinder while compressing the fuel. As a result, fuel having a pressure several times higher than the pressure of the feed pump acting on the large-diameter piston is pumped to the reservoir from the outlet port at the tip of the small-diameter cylinder. That is, the fuel pressure fed by the auxiliary pump is added to the fuel pressure fed by the high-pressure pump that rotates at a relatively low speed when the engine is started, thereby shortening the time for increasing the fuel pressure in the reservoir at the engine start.

[0005]

However, this conventional device has a problem in that the auxiliary pump needs to be newly added and the structure becomes complicated. Further, this auxiliary pump has a problem in that the cylinder and the piston, which are its constituent parts, have a special shape, which requires time and labor for manufacturing the auxiliary pump. Incidentally, at least one of the suction valve and the discharge valve of the high-pressure pump is conventionally set to a set pressure higher than the feed pump pressure.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a fuel injection control device having a high-pressure pump with a simple structure for increasing the pressure of fuel at the time of starting the internal combustion engine. Another object of the present invention is to provide a fuel injection control device for an internal combustion engine, which can be shortened by.

[0007]

In order to solve the above-mentioned problems, the invention according to claim 1 has a feed pump for supplying from a fuel tank to a high-pressure pump, and pressure-feeds the fuel pressurized by the high-pressure pump to a reservoir. In the fuel injection control device for the internal combustion engine, valve means is provided for directly delivering the fuel supplied by the feed pump to the reservoir when the fuel pressure in the reservoir is lower than a predetermined pressure.

According to a second aspect of the present invention, in the fuel injection control device for the internal combustion engine according to the first aspect, the valve means is an intake valve and a discharge valve provided in the high pressure pump. The valve and the discharge valve are check valves whose set pressures are set so that they are opened when the fuel pressure in the reservoir is lower than a predetermined pressure.

According to the first aspect of the invention, when the fuel pressure in the reservoir is lower than a predetermined pressure (for example, feed pump pressure), the fuel supplied from the feed pump is directly supplied to the reservoir via the valve means. Then, after that, when the fuel pressure in the reservoir reaches a predetermined pressure, the valve means is closed, and the fuel pressure in the reservoir is increased by pumping the fuel discharged from the high-pressure pump. Therefore, the time required for the fuel pressure in the reservoir to reach a predetermined pressure (for example, the feed pump pressure) is significantly shortened, and the startup time of the internal combustion engine is shortened.

According to the second aspect of the present invention, while the fuel pressure in the reservoir is lower than a predetermined pressure (for example, feed pump pressure), the intake valve and the discharge valve in the high pressure pump are simultaneously opened, and the feed pump The fuel having the feed pump pressure supplied from the pump is pumped directly to the reservoir through the pump chamber. Therefore, the time required for the fuel pressure in the reservoir to reach the set pressure is shortened, and the startup time of the internal combustion engine is shortened. Further, the set pressures of the intake valve and the discharge valve in the high-pressure pump need only be set so that they are simultaneously opened when the fuel pressure in the reservoir is small, and it is not necessary to add new parts. Moreover, since the valve means can be configured only by the internal structure of the high-pressure pump, the device itself becomes compact. Further, since both the intake valve and the discharge valve are check valves, they are mechanically controlled to be opened and closed, so that, for example, soft electric control which is required when using an electromagnetic valve is not necessary.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION

(First Embodiment) A first embodiment of the present invention will be described below with reference to FIGS. As shown in FIG. 1, the internal combustion engine of this embodiment is equipped with an in-cylinder injection type fuel injection device that directly sprays the fuel that has been boosted by a high-pressure pump and accumulated in the reservoir into each cylinder.

As shown in FIG. 1, a feed pump 2 for pumping fuel pumped from a fuel tank 1 through a discharge port.
Is a vane pump and is driven by a battery. The discharge port of the feed pump 2 is connected to the pressure regulator 3, and a high pressure pump 6 and an electromagnetic on-off valve 7 constituting a valve means are respectively installed on the pipes 4 and 5 that branch from the pressure regulator 3 and extend in parallel. Has been done. The pressure regulator 3 recirculates the fuel pressure-fed from the feed pump 2 to the fuel tank 1 when the fuel pressure on the discharge side exceeds its set pressure (feed pump pressure (hereinafter referred to as feed pressure)). 6 and solenoid valve 7 always have a constant pressure (feed pressure)
Pump the fuel of. In addition, in this embodiment, the feed pressure is set to 0.3 MPa.

The high-pressure pump 6 is a plunger type pump, which is directly connected to a cam shaft (not shown) of an engine 8 as an internal combustion engine and is rotationally driven in synchronization with the engine 8. The plunger that reciprocates once for each revolution of the high-pressure pump 6 sucks and discharges fuel in its pump chamber (not shown), and the fuel sucked from the suction port is discharged at a fuel pressure higher than the suction pressure. Discharge from.

The solenoid opening / closing valve 7 is a normally closed solenoid valve, which is excited and opened at the same time when the drive of the feed pump 2 is started at the time of engine start, and is demagnetized and closed at a predetermined timing described later. It has become so. Both the high-pressure pump 6 and the electromagnetic opening / closing valve 7 are connected on the downstream side to a delivery pipe 9 as a reservoir. The delivery pipe 9 has a sufficient predetermined volume so that the fuel pressure will not be lowered by a pressure drop due to one-time fuel injection and cannot be compensated by one discharge amount of the high-pressure pump 6.

A pressure sensor 10 constituting a valve means is mounted on the delivery pipe 9, and the fuel pressure in the delivery pipe 9 is detected by the pressure sensor 10. The closing timing of the electromagnetic on-off valve 7 is determined based on the detection signal from the pressure sensor 10, and is closed when the fuel pressure in the delivery pipe 9 reaches the feed pressure.

The delivery pipe 9 is connected with a number of fuel injection valves 11 corresponding to the number of cylinders of the engine 8. By opening and closing the fuel injection valves 11 at a predetermined injection timing, the inside of the delivery pipe 9 is controlled. High-pressure fuel is injected into each cylinder from an injection nozzle (not shown) for each cylinder.

The feed pump 2, the electromagnetic on-off valve 7, the pressure sensor 10 and the fuel injection valve 11 are electrically connected to an electronic control unit (ECU) 12 which constitutes valve means. E
CU12 is ON / OF from ignition switch 13
The feed pump 2 is drive-controlled based on the F signal. That is, when the ignition switch 13 is turned on, the drive of the feed pump 2 is started, and the ignition switch 1
When 3 is turned off, the drive of feed pump 2 is stopped.
Further, the ECU 12 controls the opening / closing of the electromagnetic opening / closing valve 7 based on a drive start signal that gives a drive command for the feed pump 2 and a pressure detection signal input from the pressure sensor 10. Further, the ECU 12 controls opening / closing of the fuel injection valve 11 based on an injection command signal input from the outside.

FIG. 2 shows a memory (not shown) of the ECU 12
The program data of the solenoid valve control routine shown in is stored, and the ECU 12 controls the excitation / demagnetization of the solenoid opening / closing valve 7 based on this solenoid valve control routine. The high-pressure pump 6 is equipped with a spill valve (not shown), and when the ECU 12 recognizes that the fuel pressure in the delivery pipe 9 has reached a predetermined pressure based on the pressure detection signal input from the pressure sensor 10, the spill valve is detected. The valve is opened so that the fuel injection pressure for each time is always constant.

Next, the operation of the fuel injection control device in this internal combustion engine will be described. In the state before the engine is started, the fuel pressure in the delivery pipe 9 is almost atmospheric pressure. Also,
The fuel in the delivery pipe 9 has air bubbles such as fuel vapor generated and left at the time of high temperature. Therefore, in order to increase the fuel pressure in the delivery pipe 9 to such an extent that the fuel injected in each cylinder is sufficiently atomized, and shorten the engine start time, a predetermined amount of fuel is shortened in the delivery pipe 9. Need to pump in time.

The fuel injection control by the ECU 12 of the internal combustion engine will be described below with reference to the timing chart of FIG. 3 according to the solenoid valve control routine shown in the flowchart of FIG.

First, in step 1, it is judged whether or not the ignition signal IG from the ignition switch 13 is in the ON state. When the ignition signal IG is off before the engine is started, the electromagnetic on-off valve 7 is demagnetized (OFF) in step 2 and is in the closed state. Then, when the ignition switch 13 is turned on, the starter and the feed pump 2 are slightly delayed as shown in FIG.
Is started. The feed pump 2 is driven at a constant rotation speed by using a battery as a power source, and the fuel pumped up from the fuel tank 1 is pressurized and discharged.

When the ECU 12 determines in step 1 that the ignition signal IG is turned on, the ECU 12 proceeds to step 3 and then determines whether or not the feed pump 2 is turned on. Then, in step 3, the feed pump 2
When is turned on, the process proceeds to step 4.

In step 4, it is determined based on the detection signal from the pressure sensor 10 whether the fuel pressure (delivery pressure) Pd in the delivery pipe 9 exceeds 0.3 MPa (feed pressure). The delivery pressure is low when the engine starts,
When it is 0.3 MPa or less, the process proceeds to step 5.

In step 5, the solenoid on-off valve 7 is excited (O
N) and open the valve. The opening of this electromagnetic on-off valve 7 is shown in FIG.
As shown in the time chart, the driving is started almost at the same time as the driving of the feed pump 2 is started. As a result, the electromagnetic opening / closing valve 7 opens almost at the same time when the drive of the feed pump 2 starts (see FIG.
The fuel fed under pressure from the feed pump 2 is sent to the high-pressure pump 6 to be pressurized and then discharged into the delivery pipe 9, and is fed through the pipe 5 as it is to the delivery pipe 9 under feed pressure. To be done. Therefore,
The fuel pressure (delivery pressure) Pd in the delivery pipe 9 is immediately increased to the feed pressure (0.3 MPa).

At this time, the high-pressure pump 6 is driven in synchronism with the rotation of the engine 8, but since the rotation speed of the high-pressure pump 6 is low at the time of cranking in the initial stage of driving the engine,
The amount of fuel discharged by the high-pressure pump 6 per unit time is extremely low. However, when the electromagnetic opening / closing valve 7 is opened, the fuel having the feed pressure is pressure-fed to the delivery pipe 9 through a different piping route, so that the delivery pressure Pd reaches the feed pressure (0.3 MPa) in a short time.

Then, in step 4, the delivery pressure P
When d exceeds the feed pressure, the routine proceeds to step 2, where the electromagnetic on-off valve 7 is demagnetized (OFF) to close it (see FIG. 3). Therefore, the high-pressure pump 6 alone performs only the fuel pressure feeding to the delivery pipe 9 after the delivery pressure Pd reaches the feed pressure. At this time, since the electromagnetic on-off valve 7 is closed so that the fuel in the delivery pipe 9 does not leak through the electromagnetic on-off valve 7, the fuel pressure-fed from the high-pressure pump 6 increases the delivery pressure Pd. Only effectively used.

Therefore, even if the number of revolutions of the high-pressure pump 6 is relatively low at the initial stage of engine startup and the discharge amount per discharge is relatively small, the feed pressure is immediately increased. As a result, the pressure at which the fuel injected in each cylinder is sufficiently atomized, that is, the set pressure of the delivery pressure Pd, is reached in a short time. Therefore, the starting time of the engine 8 is shortened.

After the delivery pressure Pd reaches the set value, the spill valve (not shown) built in the high-pressure pump 6 is controlled to open and close based on the detection signal from the pressure sensor 10 to deliver the delivery pipe 9. The fuel pressure inside is always maintained at a constant set pressure at the start of the injection. for that reason,
Uniform in-cylinder injection is performed at each injection timing.

When the ignition switch 13 is turned off and the drive of the engine 8 is stopped, the drive of the feed pump 2 is stopped accordingly. When the ECU 12 recognizes that the feed pump 2 has been turned off, it demagnetizes (OFF) the electromagnetic on-off valve 7 to open it. A fuel cut valve (not shown) is opened when the engine is stopped, and the fuel pressure inside the delivery pipe 9 becomes substantially equal to the atmospheric pressure.

As described in detail above, according to the present embodiment,
The effects listed below can be obtained. (A) An electromagnetic opening / closing valve 7 is provided on the pipe 5 provided in parallel with the high-pressure pump 6, and the electromagnetic opening / closing valve 7 is opened at the time of engine start, so that the fuel pressure Pd in the delivery pipe 9 is increased.
Was immediately increased to the feed pressure. Therefore, even if the number of revolutions of the high-pressure pump 6 is relatively low at the initial stage of engine start and the discharge amount per discharge is relatively small, the delivery pressure Pd is increased to the feed pressure in a short time after the engine start. can do. As a result, the starting time of the engine 8 can be shortened.

(B) Pipe 5 provided in parallel with high-pressure pump 6
A solenoid valve 7 for opening and closing the passage is provided, and the solenoid valve 7 is controlled to open and close based on the pressure detection signal from the existing pressure sensor 10. Therefore, a simple design change is required. You can Further, in the fuel injection device disclosed in Japanese Unexamined Patent Publication No. 5-321787 described in the prior art, the components of the newly provided starting auxiliary pump have a special shape and the structure thereof is complicated. However, in the fuel injection control device of the present embodiment, the components that need to be newly provided, such as the electromagnetic opening / closing valve 7, can be commercially available components, so the component cost can be made relatively low.

(Second Embodiment) Next, a second embodiment of the present invention will be described with reference to FIG. In this embodiment, the valve means for directly pressure-feeding the fuel of the feed pressure fed from the feed pump 2 to the delivery pipe 9 is provided inside the high-pressure pump 6, which is largely different from the first embodiment. different. In this embodiment, the pipe 5 and the solenoid on-off valve 7 provided in the first embodiment are used.
Is not provided, and the high-pressure pump 6 is simply arranged in series between the pressure regulator 3 and the delivery pipe 9, and other structures are similar to those of the first embodiment. Is. Therefore, only the structure of the high-pressure pump 6 will be described in detail.

FIG. 4 shows the internal structure of the high-pressure pump 6. As shown in the figure, the pump housing 21 of the high-pressure pump 6
A pump chamber 21a is partitioned and formed, and a cylindrical cylinder 21b communicating with the pump chamber 21a is provided in a protruding manner. The plunger 22 is fitted in the cylinder 21b, and the cam surface (lower surface in the figure) of the plunger 22 is in contact with the outer peripheral surface of a cam 24 that is integrally rotatably provided on the cam shaft 23. As the cam 24 rotates in synchronization with the rotation of the engine 8, the plunger 22 reciprocates in the cylinder 21b and the pump chamber 21a.
The fuel sucked in is compressed and discharged.

A check valve 25 as a suction valve is provided at the suction port of the pump chamber 21a, and a check valve 26 as a discharge valve is provided at the discharge port thereof. The check valves 25 and 26 are both set to have a set pressure equal to the feed pressure, and both are opened when the delivery pressure Pd is lower than the set pressure (feed pressure).

Further, the high pressure pump 6 is formed with a spill port 27 communicating with the pump chamber 21a, and the spill port 27 is provided with a spill valve 28 which is an electromagnetic valve for opening and closing the port. The spill valve 28 is controlled to open and close based on the pressure detection signal from the pressure sensor 10 (see FIG. 1), is opened when the delivery pressure Pd exceeds its set pressure, and the delivery pressure Pd during fuel injection is always constant. Controlled to be.

When the drive of the feed pump 2 is started with the start of the engine, the fuel of the feed pressure is pressure-fed from the pressure regulator 3 to the high-pressure pump 6. At this time,
As long as the fuel pressure (delivery pressure) Pd in the delivery pipe 9 is lower than the feed pressure, the check valves 25 and 26 are both opened as shown in FIG. 4A, and the fuel pumped from the feed pump 2 is pumped. It is pressure-fed to the delivery pipe 9 as it is through the chamber 21a. Therefore, the fuel pressure (delivery pressure Pd) in the delivery pipe 9 immediately increases to the feed pressure. At this time, in the high-pressure pump 6, the plunger 22 reciprocates in the cylinder 21b at a slow speed synchronized with the engine rotation, and the fuel pressurized in the compression process contributes to the delivery pressure Pd.

When the delivery pressure Pd reaches the feed pressure, the check valves 25 and 26 are opened and closed according to the set pressure, and both are not opened at the same time. That is, only the check valve 25 on the suction side opens during the suction stroke of the plunger 23, and only the check valve 26 on the discharge side opens during the compression stroke of the plunger 23. Further, the check valve 26 on the discharge side is opened only when the fuel pressure in the pump chamber 21a is higher than the delivery pressure Pd, so that the fuel in the delivery pipe 9 is pumped via the check valve 26. It does not flow to the chamber 21a side.

In this way, after the delivery pressure Pd reaches the feed pressure in a short time, the high pressure pump 6 only increases the pressure from the feed pressure, so that the fuel pressure (delivery pressure) Pd in the delivery pipe 9 is short. The required set pressure is reached in time. As a result, the starting time of the engine 8 is shortened.

Fuel is injected into each cylinder to deliver the delivery pressure P.
Every time d drops, the fuel discharged in the next compression stroke of the plunger 23 is pumped to the delivery pipe 9 via the check valve 26. At this time, when it is detected by the pressure detection signal from the pressure sensor 10 that the delivery pressure Pd exceeds the set pressure in the compression stroke of the plunger 23, the spill valve 28 is opened, and the spill valve 28 is compressed in the pump chamber 21a. The spilled fuel overflows through the spill port 27. Thus, in each fuel injection cycle, the delivery pressure Pd is always maintained at a constant set pressure by the time the fuel injection is started.

According to the second embodiment, the effects listed below can be obtained. (A) Check valve 2 in the high pressure pump 6 on the fuel passage
5 and 26 are provided, and these set pressures are both set to the feed pressure, and the fuel pressure in the delivery pipe 9 (delivery pressure Pd)
When is less than the feed pressure, the check valves 25 and 26 are both opened. Therefore, when the fuel pressure in the delivery pipe 9 is low at the time of starting the engine, the check valves 25 and 26 are both opened to immediately increase the delivery pressure Pd to the feed pressure, and as a result, the starting time of the engine 8 is shortened. be able to. Further, unlike the configuration of the first embodiment, there is no need to provide a new pipe 5, and no extra installation space is required. Furthermore, in comparison with the normal high pressure pump, a new check valve 25
However, even if the fuel injection control device of the present embodiment is adopted, a slight design change can be made. It can be done with a simpler configuration.

(B) Since the check valves 25 and 26 are structured to open and close mechanically according to the pressure difference between the upstream side and the downstream side, the ECU 12 like the electromagnetic opening / closing valve 7 described in the first embodiment. There is no need for soft opening / closing control.

The present invention is not limited to the above-described embodiments, but may be configured as follows, for example, within the scope not departing from the gist of the invention. (1) In the first embodiment, the electromagnetic opening / closing valve 7 may be replaced with a check valve. According to this configuration, it is possible to eliminate software control.

(2) The fuel pressure in the reservoir that allows the valve means to pump the fuel directly to the reservoir is not limited to a pressure value substantially equal to the feed pump pressure. For example, the delivery pressure Pd for closing the electromagnetic opening / closing valve 7 may be set to be smaller than the feed pressure. Also, check valves 25 and 2
The set pressure of 6 may be set smaller than the feed pressure. Even if the set pressure at which the valve means is opened is made smaller than the feed pressure, the time until the fuel pressure in the reservoir reaches the set pressure is shortened, so that the engine start time can be shortened as much as possible.

(3) A fuel passage (bypass passage) which does not pass through the pump chamber 21a may be provided in the high-pressure pump 6, and an electromagnetic valve or a check valve for opening and closing this fuel passage may be provided. According to this configuration, since the fuel passage for directly pumping the fuel to the reservoir is housed in the high-pressure pump, almost no new installation space is required,
The device itself can be made compact.

(4) The solenoid valve only needs to be able to open and close the fuel passage such as the pipe 5, and may be a flow passage switching valve provided at a branch point between the pipe passage connected to the high pressure pump and the fuel passage. Even if a flow path switching valve is adopted, a simple structure can be used.

(5) In each of the above embodiments, the present invention is applied to a gasoline engine of the cylinder injection type, but the present invention may be applied to a diesel engine. Further, it may of course be used in a gasoline engine other than the in-cylinder injection system.
If the fuel injection control device is provided with both the feed pump and the high-pressure pump, by adopting the present invention, the engine starting time can be shortened with a simple configuration using the valve means.

The invention grasped from the above-mentioned embodiment and not described in the scope of claims is described below together with its effects. (A) In the invention according to claim 1, the valve means detects a fuel passage provided in parallel with the high-pressure pump, an electromagnetic valve for opening and closing the fuel passage, and a fuel pressure in the reservoir. And a solenoid valve for opening the solenoid valve when the fuel pressure in the reservoir is lower than a predetermined pressure based on a detection signal from the pressure detecting means, and when the fuel pressure in the reservoir is equal to or higher than the predetermined pressure. And a control means for closing the solenoid valve.

According to this structure, the solenoid valve can be closed accurately when the fuel pressure in the reservoir actually reaches the predetermined pressure. Therefore, for example, when the predetermined pressure is set to the feed pump pressure, the reservoir It is possible to reliably prevent the backflow of the fuel from the reservoir caused by the closing of the valve means after the time when the internal fuel pressure actually reaches the predetermined pressure. Therefore, the pressure of the fuel in the reservoir can be efficiently increased.

[0049]

As described above in detail, according to the invention described in claim 1, when the fuel pressure in the reservoir is lower than the predetermined pressure, the valve means for directly delivering the fuel supplied by the feed pump to the reservoir is provided. Since it is provided, it is possible to shorten the time required for the fuel pressure in the reservoir to reach the feed pump pressure and thus the start-up time of the internal combustion engine with only a relatively simple structure of the valve means.

According to the second aspect of the present invention, the valve means is a suction valve and a discharge valve which are check valves provided in the high-pressure pump, and the set pressures of these are set when the fuel pressure in the reservoir is smaller than a predetermined pressure. Since it was set to be opened together with
The valve means can be configured only by the internal configuration of the high-pressure pump, and the device itself can be made compact.

[Brief description of drawings]

FIG. 1 is a circuit diagram of a fuel injection control device according to a first embodiment.

FIG. 2 is a flowchart of a solenoid valve control routine.

FIG. 3 is a timing chart showing an opening / closing operation of a solenoid valve.

FIG. 4 is a schematic cross-sectional view of a high pressure pump according to a second embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Fuel tank, 2 ... Feed pump, 6 ... High pressure pump, 7 ... Electromagnetic on-off valve which comprises valve means, 8 ... Engine as an internal combustion engine, 9 ... Delivery pipe as reservoir, 10 ... Pressure which constitutes valve means Sensor, 12 ... ECU constituting valve means, 25 ... check valve as intake valve,
26 ... Check valve as a discharge valve.

Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location F02M 55/02 350 F02M 55/02 350P 63/00 63/00 R

Claims (2)

[Claims] 1. A fuel injection control device for an internal combustion engine, comprising: a feed pump for supplying a high pressure pump from a fuel tank; and a fuel boosted by the high pressure pump to a reservoir, wherein the fuel pressure in the reservoir is lower than a predetermined pressure. A fuel injection control device for an internal-combustion engine, comprising valve means for directly delivering the fuel supplied by the feed pump to the reservoir when it is small. 2. The valve means is an intake valve and a discharge valve provided in the high-pressure pump, and the intake valve and the discharge valve are both opened when the fuel pressure in the reservoir is lower than a predetermined pressure. The fuel injection control device for an internal combustion engine according to claim 1, wherein the check valve is a check valve whose set pressure is set to 1.