JPS60162021A - Fuel injection control device of internal-combustion engine - Google Patents

Abstract

PURPOSE:To ease adjustment of injection timing, injection quantity and injection pressure by separately providing a solenoid valve which controls pressurized oil fed to a booster which highly pressurizes injection pressure of the fuel and a solenoid valve for injection control. CONSTITUTION:Working oil from the first pressure source 1 is introduced to a pressure receiving face 71 of big diameter on one end of mobile bodies 7, 8 of a booster 3 through the first solenoid valve 5 which is opened only for a period exceeding an injection period, while fuel oil from the second pressure source 2 is introduced into a pressure chamber 10 on a pressure receiving side 72 of small diameter of the other end through the first check valve 13. Subsequently, the fuel oil from the pressure chamber 10 is given into a pressure accumulation chamber 12 through the second check valve 11, then said fuel oil from the accumulation chamber 12 is injected from a nozzle hole 51 through a control valve 31 which makes pilot operation by means of the second solenoid valve 6. Thus injection timing, injection quantity and injection pressure can be easily adjusted.

Description

Detailed Description of the Invention Technical Field The present invention relates to an internal combustion engine in which fuel injection timing, fuel injection amount, and fuel injection pressure can be easily adjusted without completely stopping the internal combustion engine and without depending on the rotational speed of the internal combustion engine. The present invention relates to a fuel injection control device.

BACKGROUND ART In general, in internal combustion engines, and in diesel engines in particular, fuel injection timing greatly affects engine performance, particularly fuel consumption rate.

In addition, the fuel injection pressure can be increased to make the fuel spray finer and the injection period shorter, increasing the combustion efficiency and reducing the fuel consumption rate. However, when the internal combustion engine is under low load, daytime pressure injection The internal combustion engine that causes the knock becomes strained, leading to a shortened engine life and excessive noise. The optimal values for injection timing and pressure vary greatly depending on the operating conditions of the internal combustion engine and the quality of the fuel oil, so if the fuel injection timing and fuel injection pressure could be freely adjusted while the internal combustion engine is running, it would be possible to significantly reduce the amount of fuel used. Savings can be made without forcing the internal combustion engine, and considering the current situation of soaring oil prices,
generate big profits.

Conventionally, a fuel injection system for an internal combustion engine is constructed by directly connecting a fixed stroke fuel injection pump that is driven in synchronization with the operation of the internal combustion engine and an automatic injection nozzle with a shutoff valve with all fuel injection pipes connected. , has been widely adopted around the world. In this conventional fuel injection system, the fuel injection timing is determined by the set position of the cam, and when changing the fuel injection timing, it is necessary to change the set position of the cam on the camshaft, and the internal combustion engine must be stopped first. There must be. Furthermore, the fuel injection pressure is determined by the rotational speed of the internal combustion engine and the dimensions of the injection nozzle.
It cannot be adjusted freely.

On the other hand, in a fuel injection device already known in Japanese Patent Application Laid-Open No. 56-143344, an electro-hydraulic servo valve is equipped on an injection nozzle with a shutoff valve, and the fuel flow path is switched using liquid pressure other than fuel. The fuel injection device injects and supplies the fuel accumulated in the high-pressure fuel source into the cylinder from the injection nozzle, and the start and end of the injection is controlled by electric and pneumatic pulse signals applied to the electro-hydraulic servo valve. However, according to such a device, the fuel injection timing and fuel injection amount are determined by the transmission timing and pulse width of the electric pulse signal, and the fuel injection pressure is determined by the fuel pressure accumulated in the high-pressure fuel source. Therefore, the fuel injection timing, fuel injection amount, and fuel injection pressure can be freely adjusted regardless of the speed of the internal combustion engine or the installation of the cam. However, in such a device, it is necessary to maintain a state in which high-pressure fuel equivalent to the injection pressure is stored in the gastric pressure fuel source at all times regardless of the injection period, and the piping between the high-pressure fuel source and the fuel valve is required. Unless the pressure loss caused by this and the instantaneous pressure drop caused by discharge during fuel injection are fully compensated for, a high fuel injection rate from the fuel valve cannot be maintained and a high injection pressure cannot be achieved.

The fuel injection pressure in marine engines is usually 600 to 1500 k
Due to the extremely high pressures of g/cm2 and combustible materials, the means of mitigating pressure fluctuations in high-pressure fuel sources is usually the volume of the fuel itself rather than the gas-pressure accumulators used in hydraulic pipeline systems. There is no choice but to use a pressure vessel that utilizes elasticity.

Therefore, the volume of the pressure vessel is determined by how much pressure fluctuation range is allowed in the balance between the maximum discharge amount and the supply amount. Since the fuel injection period in a marine engine is approximately 30 degrees crank angle, the engine speed is f 500 rpm.
If so, it will take about 10m5. When considering pressure fluctuations within a short period of time, the supply amount can be ignored in practice, so for example, the discharge amount per cycle is 115 m.
1! As a result, the allowable pressure fluctuation range within the injection period '53
Assuming 0 kg/Cm2, a simple calculation requires a volume of approximately 8.51.

Due to its strength, the structural dimensions of the pressure vessel that holds all of this large amount of ultra-high pressure fuel must be considerably larger than the dimensions of conventional fuel injection pumps for internal combustion engines, which increases production costs and reduces the impact on the engine. There is a problem with the casting method. Furthermore, due to the size of the pressure vessel mentioned above, it has to be placed separately from the cylinder head where the fuel injection valve is installed, so the ultra-high pressure fuel is communicated between the pressure vessel and the fuel injection valve through the injection pipe. However, it is necessary to improve the strength and sealing performance of injection pipes and joints to withstand ultra-high pressure. Furthermore, it is necessary to supply ultra-high pressure fuel through the entire relatively long injection pipe within a very short period of time, and the flow velocity in the pipe increases, so as mentioned above, the pressure loss increases and it becomes difficult to maintain the specified injection pressure. Not only is it necessary to increase the source pressure in the pressure vessel, but pressure pulsations in the injection pipe can cause the pressure inside the injection pipe to become abnormally high or low, which can reduce injection performance and pose a risk of damage to the joint. , there is a problem that irregular injections such as secondary and tertiary injections occur. Furthermore, as the container holding the high-pressure fuel becomes larger and the injection pipe through which the high-pressure fuel passes becomes longer, the chances of fuel leaking increase. When high-pressure fuel leaks, it often becomes atomized, increasing the risk of fire.

A fire on a ship causes great damage to the ship and the lives of its crew.

On the other hand, in order to solve the above problem, there is a prior art that employs a pressure increasing structure using a booster that fully applies Pascal's principle as a means of increasing the fuel injection pressure to an extra pressure. In this prior art, the amount of hydraulic oil supplied to the drive-side pressure chamber at low pressure is greater than the amount of fuel injection by the pressure increase ratio.

For example, if the required injection amount of fuel with an injection pressure of 1500 kg/Cm2 is 15 m/ with an injection time of 10 ms, then
If the pressure increase ratio is 7, then a simple calculation will yield approximately 214 kg/c.
m 2 of hydraulic oil f 105 ml in 10 ms
This means that it is necessary to supply only The start of fuel injection is achieved by communicating the hydraulic oil between the pressure source and the drive-side pressure chamber of the booster through the solenoid valve, so the flow rate of the pressure oil through the solenoid valve is about 630 l/min.

The solenoid valve has a direct-acting type that uses electromagnetic force to move the entire spool to switch the pressure oil flow path, and a @-acting type solenoid valve that uses the driving force of the switched pressure oil to move the main spool and switch the pressure oil flow path. There is a pilot type. In the case of high pressure and large flow rate, a pilot type is usually adopted because the fluid force acts on the spool during the switching operation with a direct acting type, making it impossible to switch. However, in the case of a pilot type, there is a limit to achieving fast response due to its structure because it requires multiple steps of operation. -The control precision required for fuel injection in an internal combustion engine is 1 to 2 degrees of crank angle, and at a rotation speed of 500 rpm, it is 0.3 to 0.
This results in an extremely minute time accuracy of 7 ms. Therefore, it is impossible with the current technology to perform highly accurate fuel injection control of an internal combustion engine using a solenoid valve that handles high pressure and large flow rate as described above. In view of this, we have developed a solenoid valve that controls the large flow of pressure oil sent to the booster with a pressure booster structure required to achieve super cylinder pressure, and a small flow solenoid valve that performs highly accurate fuel injection control of the internal combustion engine. By sharing the injection function, the above-mentioned νξ point is resolved, and the fuel injection timing, fuel injection amount, and
It is an object of the present invention to provide a highly reliable and inexpensive fuel injection control device for an internal combustion engine that can easily adjust fuel injection pressure and increase the fuel pressure.

In the present invention, hydraulic oil from the first pressure source 1 is supplied to one end of the movable body 7.8 in the booster 3 through the first electromagnetic box 5 which is kept open for at least a period W2 which is longer than the fuel injection period W1. Fuel oil is introduced from the second pressure source 2 into the pressure chamber 10 on the small diameter pressure receiving surface 72 side at the other end of the movable bodies 7 and 8 via the first check valve 13. , this pressure chamber 1
The fuel oil from the pressure accumulation chamber 12 is supplied to the pressure accumulation chamber 12 via the second check valve 11, and the fuel oil from the pressure accumulation chamber 12 is injected from the nozzle hole 51 via the control valve 31. This fuel injection control device for an internal combustion engine is characterized in that it is pilot-operated by hydraulic oil that passes through the second electromagnetic valve 6 from the fuel injection control device.

A preferred embodiment of the present invention is characterized in that a valve means is connected to the passage 35 between the control valve 31 and the nozzle hole 51, which closes when the control valve 31 is opened and opens when the control valve 31 closes. This is a fuel injection control device for an internal combustion engine.

Another preferred embodiment of the present invention is a fuel injection control device for an internal combustion engine, characterized in that it is provided with a safety valve 80 that opens when the pressure in the pressure accumulation chamber 12 increases abnormally.

In a further preferred embodiment of the present invention, the control valve 31
The valve body 31a fully controls the supply of fuel oil, and the valve body 31a
The control piston 37 includes a first pressure receiving surface 83 on the valve body side and a second pressure receiving surface 73 on the opposite side of the valve body 31a that are connected to each other. 1
00 and a second pressure-receiving surface 101.

The present invention will be explained in detail with reference to the drawings. FIG. 1 is a block diagram showing a first embodiment of the present invention.

The first pressure source 1 is connected to the pressure chamber 9 from the connection port 19 of the booster 3 by the conduit 15 through the conduit 55, the check valve 17, and the first electromagnetic valve 5, and by the conduit 43 branching from the conduit 55. The pressure chamber 3 is connected from the connection port 39 of the fuel injection valve 4 through the passage 41 via the check valve 42 and the 211th magnetic valve 6.
8 can be connected. An accumulator 18 in the conduit 15, 43 for absorbing all the pressure pulsations in the conduit.
44 are connected. Two second pressure sources are connected via a conduit 27 from the connection 21 of the booster 3 to the pressure chamber 10 via a spring-loaded check valve 13 .

Inside the booster 3, a piston 7 that slides on the upper cylinder 66t and a plunger 8 that slides on the lower cylinder 67 are disposed, and the piston 7 and the plunger 8 are pressed against each other. The pressure chamber 9 formed by the cylinder 66 and the top surface 71 which is a large-diameter pressure receiving surface at the upper end of the piston 7 is supplied with hydraulic oil from the first pressure 1 through the first solenoid and the valve 5. It is available for supply. The pressure chamber 10 formed by the cylinder 67 and the small diameter pressure receiving surface 72 at the lower end of the plunger 8 is filled with fuel oil supplied from the second pressure well 2 via the check valve 13 as described above. It is now possible. The pressure chamber 10 is connected to a pressure accumulation chamber 12 disposed below the booster 3 through a double check valve 11 .

The pressure accumulation chamber 12 is communicated with the fuel injection valve 4 through a passage 22 . The passage 22 communicates with a fuel reservoir 48 by a passage 35.

The fuel injection valve 4 is composed of a control section A and a valve section B. In the control section A, a control valve 31 that slides on a cylinder 69 and a control piston 37 that slides on a cylinder 68 are disposed in pressure contact with each other. The pressure chamber 38 formed by the cylinder 68 and the surface 73 of the control piston 37 on the opposite side of the control valve 310 is filled with hydraulic oil supplied from the first pressure source 1 via the connection port 39 . The valve portion B is provided with an injection valve body 47 that slides on the cylinder 70 and a valve spring 46 that urges the injection valve body 47 in a direction to press it against the seat surface 50 of the nozzle hole 51.

In the first pressure source 1., the pressure of hydraulic oil is increased from the tank 61 through the filter 59 by the pump 58. Pressure regulating valve 5
Pressure oil whose pressure is regulated by 7 is supplied to conduit 55 via filter 56 .

In the second pressure source 2, the fuel oil is transferred from the tank 65 to the filter 6.
Pressure oil is supplied to the conduit 27 via the pump 63 and the pressure regulated by the pump 63 via the pump 63 .

The piston 14 is movable up and down in FIG. 1 within the cylinder 24, and is urged upward in FIG. 1 by a valve spring 25 so that the pressure chamber 23 communicating with the pressure accumulation chamber 12 becomes smaller. When the piston 14 is displaced against the spring force of the spring 25 and the pressure chamber 23 becomes thicker, the pressure chamber 23 becomes larger than the passage 7.
6 to a conduit 29. When the valve body 31a of the control valve 31 is seated on the seat surface 32 and in the closed state, the annular groove 33 formed in the valve body 31a allows the passage 36 to flow from the connection port 52 through the drain pipe's3.54%. It communicates with tank 65. When the control valve 31 opens, the passage 36 and the connection port 52 are cut off.

The maximum strokes of the piston 7 and the plunger 8 are selected such that the maximum stroke volume of the plunger 8 is slightly larger than the sum of the maximum injection amount per injection and the compressed volume of fuel required for high-pressure accumulation.

Next, the operation will be explained according to FIG.

The left solenoid of the first solenoid valve 5 is energized to position 5b.
At one time, the flow path is switched so that the connection port 19 of the booster 3 communicates with the entire tank 61 via the return conduit 16 in which the throttle valve 60 is interposed with respect to the pressure chamber 9 . At this time, fuel is supplied to the pressure chamber 10 of the booster 3 from the second pressure source 2 at a pressure higher than the cracking pressure of the check valve 13 via the conduit 27, the connection port 21 of the booster 3, and the check valve 13, The pressure pushes the plunger 8 and piston 7 upward in a direction that reduces the volume of the pressure chamber 9, and the top surface 71 of the piston 7 comes into pressure contact with the end surface 74 of the cylinder 66 and stops. The moving speeds of the plunger 8 and the piston 7 are limited by a throttle valve 60 disposed in the middle of the return conduit 16, so that the piston 7 is prevented from running out of control due to the fuel made highly pressurized by the pump 63, and the stroke end is reached. impact force is alleviated.

The second solenoid valve 6 is in position 6 when the left solenoid is energized.
In b, the flow path is switched so that the connection port 39 of the pressure chamber 38 communicates with the conduit 43. Therefore, in the control valve 31 of the fuel injection valve 4, the pressure oil from the first pressure source 1 acts on the surface 73 of the control piston 37, and the control piston 37 is urged to the left in FIG. The valve body 31a of the control valve 31 is connected to the seat surface 32 facing the valve body 31a of the control section A.
The connection port 22 and the passage 35 are connected to the control valve 31.
It is blocked by.

An extremely high pressure higher than the supply pressure from the second power source 2 is accumulated in the pressure accumulation chamber 12 of the booster 3 .

The pressure accumulation chamber 12 is isolated from the pressure chamber 10 by a spring-biased check valve 11 and is isolated from the passage 76 by a safety valve 80.
and the passage 35 by the control valve 31.

A passage 36 that branches off from the middle of the passage 35 of the fuel injection valve 4 communicates with the tank 65 from the connection port 52 via the drain pipe 53,545 through the annular groove 35 formed in the valve body 31a of the control valve 31. Control valve 31, pressure chamber 34, passage 35
, 36, 52, and the fuel reservoir 48 are filled with fuel open to atmospheric pressure.

The injection valve 47 of the valve portion B is biased by the valve spring 46, and the tip 49 of the injection 9f 47 is pressed against the seat surface 50, thereby blocking the fuel reservoir 48 from the nozzle hole 51.

Next, the right solenoid of the first solenoid valve 5 is energized and the second
As shown in FIG. 9. Therefore, the piston 7 and the plunger 8 are pushed down to the first position, compressing the fuel filling the pressure chamber 10. Except for this, the accumulator 18 is connected to the conductor W15.
It works effectively to prevent a temporary drop in the pressure of the hydraulic oil inside. Top surface 71 of piston 7 relative to bottom 72 of plunger 8
If the area ratio is 'kK (K>1), then a pressure twice as high as the pressure in the pressure chamber 9 will be generated in the pressure chamber 10.

This is called the Ki pressure intensification ratio. At this time, since the control valve 31 is in a shut-off state, the piston 7 and plunger 8 are stopped. Since the pressure in the pressure chamber 10 is higher than the pressure in the connection port 21, the check valve 13 is closed.

Since the pressure in the pressure chamber 10 and the pressure in the pressure accumulation chamber 12 are almost the same, the check valve 11 is closed by the spring force. The second current valve 6 is in position 6b, and the area ratio between the valve body 31a and the control piston 37 is such that the area ratio of the pressure chamber 38 acting on the surface 73 of the piston 37 is greater than the driving force in the valve opening direction due to the pressure of the connection port 22. It is selected so that the driving force in the valve closing direction due to pressure is sufficiently large. Therefore, the control valve 31 maintains the closed state. Thereafter, when the right solenoid of the second solenoid valve 6 is energized, the flow path of the second solenoid valve 6 is switched to position 6a, and the connection is made. Port 39 communicates with return conduit 45 and pressurized oil in pressure chamber 38 is discharged to tank 61 . Therefore, the control valve 31 opens from time t2 to time t3 in FIG. 2(2) due to the driving force of the pressure oil from the connection port 22 side. As the valve body 31a moves to the right in FIG. The passage 35 is connected to
High-pressure fuel oil flows into the pressure storage chamber 12 from the pressure storage chamber 12 .

As a result, the pressure inside the pressure chamber 48 becomes high and the injection valve 4
The driving force acting on the stepped portion 75 of No. 7 overcomes the spring force of the valve spring 46 biasing in the valve closing direction, the injection valve 47 is fully opened, and high pressure fuel is injected from the nozzle hole 51.

After the start of injection, from the pressure accumulation chamber 12 through the entire passage 35 to the nozzle hole 5
At the same time, the check valve 11 opens and the pressure storage chamber 12 is supplied with high-pressure fuel from the pressure chamber 10. The piston 7 moves the plunger 8 when supplied with sufficient pressure oil from the first pressure source 1. Therefore, the pressure chamber 10 is maintained at a high pressure, and fuel is supplied to the nozzle hole 51 while its injection pressure is maintained at a high pressure.

After the predetermined injection time W1 has elapsed, the left solenoid of the second electromagnetic valve 6 is energized at time t3, and the flow path is switched to position 6b so that the connection port 39 and the conduit 43 communicate with each other. Therefore, pressure oil from the first pressure source 1 is supplied to the pressure chamber 38 .

Therefore, the control piston 37 and the valve body 31a are urged in the valve opening direction by the driving force of the control piston 37, and are pressed against the valve seat 32 to pass through the connection port 22 and pass through the passage 3.
5 is also blocked. At this time, as the valve body 31a moves in the valve closing direction, the annular groove 33 connects the passage 36 and the connection port 52.
, the high pressure fuel oil filling the passage 35 is discharged to the drain pipes 53 and 54, and the pressure drops rapidly. As a result, the driving force acting on the injection valve 47 in the valve opening direction in the fuel reservoir 48 instantly becomes smaller, and due to the spring force of the valve spring 46 in the valve closing direction, the injection valve 47 moves in the valve closing direction. The valve is energized, and the tip 49 of the injection valve 47 is pressed against the valve seat 50 to close the valve. Therefore, fuel injection from the nozzle hole 51 is completed. The drained oil from the annular groove 33 helps to eliminate so-called "fuel exhaustion" and is effective in improving fuel efficiency.

The control piston 370 stroke is negligible, for example on the order of 1 mm. Therefore, the flow rate of the hydraulic oil passing through the second solenoid valve 6 is small. Therefore, the driving force required by the hydraulic oil is small and all direct-acting solenoid valves can be used. This makes it possible to improve the accuracy of injection timing and adjustment.

When the valve portion B is closed, high pressure is instantaneously generated in the pressure accumulation chamber 12 and the pressure chamber 10 due to the acceleration of the piston 7 and the plunger 8. At this time, the volume of the pressure chamber 23 of the safety valve 80 that opens to the pressure accumulation chamber 12 increases due to the displacement of the piston 14 that slides against the spring force of the spring 25, so that the impact pressure is absorbed. When the pressure chamber 23 acts as a buffer volume due to some abnormality, the piston 1
When moving downward in Figure 1 beyond a certain value of 4, passage 7
6 communicates with the pressure chamber 23 and high pressure fuel is discharged from the conduit 29 into the tank 65. Therefore, the pressure accumulation chamber 12 is prevented from becoming abnormally high pressure. The pressure in the pressure accumulator 12 is applied to the piston 7
As the plunger 8 is stopped and leveled, the piston 14 is pushed back by the spring 25.

After the fuel injection ends, at time t4 in FIG.
9 and the return conduit 16 are switched so that the pressure oil in the pressure chamber 9 is transferred from the return conduit 16 to the tank 6 through the throttle valve 60.
It is discharged to 1. At this time, as the pressure oil is discharged from the pressure chamber 9, the piston 7 and the plunger 8 move upward due to the driving force of the fuel in the pressure chamber 10, the volume of the pressure chamber 10 increases, and the pressure decreases. The pressure chamber 10 has a check valve 11
Since the pressure accumulation chamber 12 is cut off by
2, a high pressure is maintained. When the pressure in the pressure chamber 10 becomes lower than the pressure in the connection port 21 by the cracking pressure of the check valve 13, the check valve 13 opens and the interpressure fuel is replenished from the second pressure source, causing the piston top surface 71 to Seat surface 7 of cylinder 66
Press 4 to stop. The opening and closing of the throttle valve 60 disposed in the middle of the return conduit 16 is adjusted so as to limit the moving speed of the piston 7 and the plunger 8 due to the driving force of the pressure oil in the pressure chamber 10.

The flow rate of the hydraulic oil passing through the first solenoid valve 5 is determined by the pressure increase ratio in order to completely improve the combustion performance. It is thick and produces a large amount of injection in a short time, resulting in a large flow rate. At a rotation speed of 500 rpm,
When 1lcc of fuel is injected at a crank angle of 25 degrees, the pressure increase ratio is 8. Therefore, the first solenoid valve 5 must be of the Byronto operation type, although pilot operated solenoid valves have poor response. , the pressure chamber 10 may be refilled with fuel within a sufficiently long period of time other than the injection period, and the first solenoid valve 5
Unlike the second solenoid valve 6, high-speed switching is not required. In fact, when controlling the injection period and injection timing in units of 1 degree of crank angle in an internal combustion engine rotating at 500 rpm, the second solenoid valve 6 is required to have a certain degree of responsiveness, but the first solenoid valve 5 is required to control the injection timing. When the angle is set to 25 degrees, it is only necessary to switch the flow path and replenish the entire fuel pressure chamber 10 during this period, so the response may be 1/10 or less compared to the second electromagnetic valve 6.

In the embodiment configured as described above, the ultra-high pressure fuel is accumulated every 01 injection cycles, and the booster 3 acts to always supply the fuel within the injection period, so that a stable injection rate can be obtained.

A large-capacity ultra-high-pressure pressure vessel is not required.

(2) Since the booster 3, which is a pressure accumulating container, can be miniaturized, the booster 3 can be connected closely or directly to the injection valve 4. Therefore, the pressure loss in the pressure accumulator 12, which is a pressure vessel, can be reduced, and by omitting piping, it is possible to suppress the occurrence of fuel leakage and prevent the occurrence of fire.

■A large-capacity ultra-high-pressure pressure vessel is not required, and pressure piping that is smaller than the injection pressure is sufficient from the hydraulic oil pressure well to the booster, so conventional piping joints can be used and are inexpensive.

■In the conventional pressure booster fuel injection device operated by hydraulic pressure, the impact force generated when the booster piston or plunger is seated was a problem, but in the case of the present invention, the problem is that the pressure force generated when the booster piston or plunger is seated is disposed in the pressure accumulation chamber 12 for the side pressure part. Overpressure in the pressure storage chamber 12 can be prevented by the shock absorbing piston and the piston 14 that constitutes a safety valve.

(2) By disposing all check valves 11 and 13 in the pressure accumulating chamber 12, fuel can be supplied and a small amount of fuel can be injected.

■A large-capacity solenoid valve is required to supply high-pressure hydraulic oil for pressure increase, but conventional methods simply control injection timing, which requires extremely high control precision in both response and reproducibility. Because it is operated by one solenoid valve, it has a large capacity and precision.
't-Achievement at the same time is incompatible. In the present invention,
By having the individual solenoid valves 5 and 6 share the function of generating the hydraulic driving force required for pressure increase and the function of controlling the injection period, fuel injection by hydraulic operation can be achieved.

■Since a booster 3 and an injection valve 4 are provided for each cylinder, and the injection thread is independent for each cylinder, interference between cylinders can be prevented like in a high-pressure injection device, and this configuration for one cylinder can be Even if a failure occurs, the internal combustion engine can continue operating in other cylinders, making the engine highly reliable.

■The control part A and the valve part B are integrally combined to form the fuel injection valve 4.
, so piping is omitted. Therefore, fuel leakage is prevented, and the occurrence of a fire due to fuel leakage is also prevented.

FIG. 3 is a block diagram of another embodiment of the present invention.

This embodiment is similar to the embodiment of FIGS. 1 and 2, and corresponding parts have been given the same reference numerals.

What should be noted is that the pressure of the fuel in the pressure accumulation chamber 12 causes an upward force to act on the stepped portion of the valve body 31a of the control valve 31 in FIG. 3, causing the valve to open. .

As yet another embodiment of the present invention, the throttle valve 60 is
Instead of intervening in 6, it may be interposed in conduit 27.

FIG. 4 1d is a block diagram showing still another embodiment of the present invention. These embodiments are similar to the previously described embodiments and corresponding parts are provided with the same reference numerals.

What should be noted is that the second solenoid valve 6 is a four-way valve, and the second valve is placed on both sides of the control piston 37.

A pressure chamber 38 having a first pressure receiving surface 100 and a second pressure receiving surface 101
a and 38b are connected to the conduit 4 to which pressure is applied by the second solenoid valve 6.
The control piston 371 is biased to the right in position 6a and to the left in switching position 6b.

In the fourth illustration, the first electromagnetic valve 5 is at the switching position 5a, the second tortoise valve 6 is at the switching position 6bK, and the time t in FIG.
1 and t2. Fuel oil pressurized by the booster 3 is held in the pressure chamber 10 and the pressure accumulation chamber 12, and the valve portion B is closed. In other words, the force exerted by the fuel oil that urges the control valve 31 to the right through the passage 22 is
The force is smaller than the force exerted by the hydraulic fluid that urges the control piston 37 to the left, and the control valve 31 is closed. For this reason, passage 3
5 pressure is released to the tank, and the valve body 47 is connected to the spring 4
6 and is closed. When the second solenoid valve 6 is switched to the state shown in 6a at time t2, the pressure chamber 38a
The pressure conduit 43 is connected to the pressure chamber 38b, and the relief conduit 45 is connected to the pressure chamber 38b.
j: Since the control piston 37 is forced to the right, the control valve 31 moves to the right, and the fuel in the pressure accumulator 12 flows into the passage 2.
2 to the fuel storage 48. The valve body 47 is biased by the fuel pressure and rises against the resistance of the spring 46, causing injection into a cylinder chamber (not shown). At time t3, the second magnetic valve 6 is switched again, and the state shown in the fourth figure is reached, and the control valve 3 is switched again.
It moves one place to the left and the valve closes, thus ending the injection.

FIG. 5 is a block diagram showing another embodiment of the present invention. These embodiments are similar to the previously described embodiments and corresponding parts are provided with the same reference numerals. What should be noted is the second solenoid valve 6.
A four-way valve is used for the control piston 370, and the pressure chamber 38a is connected to the first pressure receiving surface 100 and the second pressure receiving surface 101 arranged on both sides of the control piston 370.

38b can be alternately connected to the pressured conduit 43 and the relief conduit 45 by the second solenoid valve 6,
The control piston 37 is biased upwardly at the switching position 6a and downwardly at the switching position @6b. 5th (9th
) shows that the first solenoid valve 5 is at the switching position @5a, the second solenoid valve is at the switching position 6b, and the times t1 and t in FIG.
It shows the condition between 2. Pressure chamber 10 and pressure accumulation chamber 1
2 holds fuel oil whose pressure has been increased by the booster 3, and the valve portion B7-j is closed. In other words, the force exerted by the fuel oil that urges the control valve 31 upward through the passage 22 is
The force is smaller than the force exerted by the hydraulic fluid that urges the control piston 37 downward, and the control valve 31 is closed. For this reason, passage 3
The pressure of 5 is released to the tank, and the valve body 47 is connected to the spring 46.
It is energized and blooming.

When the second solenoid valve 6 is switched to the state shown in 6a at time t2, the pressure conduit 43 is connected to the pressure chamber 38a.
Since the relief conduit 45 is connected to 8b and the control piston 37 is urged upward, the control valve 31 moves upward and the fuel in the pressure accumulation chamber 12 flows from the passage 22 to the fuel reservoir 48. The valve body 47 is biased by the fuel pressure and rises against the resistance of the spring 46, and injection is performed into a cylinder chamber (not shown). Time t
3, the second electromagnetic valve 6 is switched again to the state shown in FIG. 5, and the control valve 31 moves downward and is closed, thus ending the injection.

As described above, according to the present invention, the fuel injection timing, fuel injection amount, and fuel injection pressure can be easily adjusted without completely stopping the internal combustion engine and without depending on the rotational speed of the internal combustion engine.
Moreover, fuel pressure can be increased.

[Brief explanation of drawings]

Fig. 1 is a block diagram of one embodiment of the present invention, Fig. 2 is a graph for explaining the operation of the embodiment shown in Fig. 1, and Fig. 3 is a block diagram of another embodiment of the present invention. , FIG. 4 is a block diagram of still another embodiment of the present invention, and FIG. 5 is a block diagram of another embodiment of the present invention. 1... First pressure source, 2... Second pressure γkon, 3...
Booster, 4... Fuel injection valve, 5, 6... Solenoid valve,
7... Piston, 8... Granger, lO... Pressure chamber, 11.13... Check valve, 12... Pressure accumulation chamber, 3
1... Control valve, 35... Passage, 51... Nozzle hole, A... Control section, B... Valve department agent Patent attorney Shin Saikyo Department

Claims (4)

[Claims] (1) Hydraulic oil from the first pressure source 1 is supplied to one end of the movable bodies 7 and 8 in the booster 3 via the first electromagnetic valve 5 that is open for at least a period W2 that is longer than the fuel injection period W1. Fuel oil is introduced from the $2 pressure source 2 through the first check valve 13 into the pressure chamber 10 on the side of the small diameter pressure receiving surface 72 at the other end of the movable bodies 7 and 8. , this pressure chamber 10
The fuel oil from the pressure storage chambers 12'75. The fuel oil is injected from the nozzle hole 51 via the control valve 31, and the control valve 31 is operated in a bidirectional manner by the hydraulic oil from the first pressure source 1 via the second electromagnetic valve 6. A fuel injection control device for internal combustion engines. (2) The fuel injection control device for an internal combustion engine according to claim 1, further comprising a safety valve 80 that opens when the pressure in the pressure accumulation chamber 12 increases abnormally. (3) The passage 35 between the control valve 31 and the nozzle hole 51 is fully connected to a valve means that closes when the control valve 31 is opened and opens when the control valve 31 closes. A fuel injection control device for an internal combustion engine according to item 1 or 2. (4) The control valve 31 is a valve body 31 that controls the supply of fuel oil.
a, and a control piston 37 connected to the valve body 31a and having a first pressure receiving surface 83 on the valve body side and a second pressure receiving surface 73 on the opposite side to the valve body 31a, and hydraulic oil flowing through the second solenoid valve 6. The fuel injection control device for an internal combustion engine according to claim 1, wherein is selectively applied to the first pressure receiving surface 100 and the second pressure receiving surface 101.