JPH0544539B2 - - Google Patents

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 stopping the internal combustion engine and independent of 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 fuel efficiency and reducing the fuel consumption rate. However, when the internal combustion engine is under low load, high-pressure injection This causes knocking and puts strain on the internal combustion engine, leading to a shortened engine life and excessive noise. The optimum injection timing and pressure vary greatly depending on the operating conditions of the internal combustion engine and the quality of the fuel oil.
If the fuel injection timing and fuel injection pressure could be adjusted freely even while the internal combustion engine is running, it would be possible to save a large amount of fuel without forcing the internal combustion engine to do so, and considering the current situation of soaring oil prices, this would generate large profits.

Conventionally, a fuel injection device for an internal combustion engine is configured 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 via a fuel injection pipe. Widely adopted around the world. In this conventional fuel injection device,
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 temporarily stopped. Furthermore, the fuel injection pressure is determined by the rotational speed of the internal combustion engine and the dimensions of the injection nozzle, and cannot be freely adjusted.

On the other hand, in a fuel injection device already known in JP-A-56-143344, an injection nozzle with a shutoff valve is equipped with an electro-hydraulic servo valve, and the fuel flow path is switched using liquid pressure other than the fuel. There is a fuel injection device that injects and supplies fuel accumulated in a high-pressure fuel source into a cylinder from an injection nozzle, and the start and end of the injection is controlled by an electric pulse signal applied to the electrohydraulic servo valve. 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. 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,
Regardless of the injection period, it is necessary to maintain a state in which high-pressure fuel equivalent to the injection pressure is stored in the high-pressure fuel source at all times, and pressure loss due to piping between the high-pressure fuel source and the fuel valve and during fuel injection must be maintained. Unless the instantaneous pressure drop caused by the discharge of fuel is compensated for, a high fuel injection rate from the fuel valve cannot be maintained and a high injection pressure cannot be achieved.

Fuel injection pressure in marine engines is usually 600 to 1500
Because it is a combustible material and has a very high pressure of Kg/cm ² , the means to alleviate pressure fluctuations in high-pressure fuel sources uses the bulk elasticity of the fuel itself, rather than the gas-pressure accumulator normally used in hydraulic pipeline systems. There is no choice but to use a pressure vessel with a high temperature.

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. The fuel injection period in a marine engine is approximately 30 degrees of crank angle, so if the engine speed is 500 rpm, the period is approximately 10 ms.
When considering pressure fluctuations within such a short period of time, the supply amount can be ignored in practice, so for example 1
If the discharge amount per cycle is 15ml and the allowable pressure fluctuation range within the injection period is 30Kg/ ^cm2 , then
A simple calculation requires a volume of approximately 8.5.

The structural dimensions of a pressure vessel that holds such a large amount of fuel under ultra-high pressure must be considerably larger than the dimensions of a conventional fuel injection pump for an internal combustion engine due to its strength, which increases manufacturing costs and reduces the impact on the engine. There is a problem with the installation method. Furthermore, due to the size of the pressure vessel, it is necessary to install it separately from the cylinder head where the fuel injection valve is installed.
Ultra-high pressure fuel is communicated between a pressure vessel and a fuel injection valve through an injection pipe, but it is necessary to improve the strength and sealing performance of the injection pipe and joints so that they can withstand the ultra-high pressure. Furthermore, it is necessary to supply ultra-high pressure fuel in a very short time through a relatively long injection pipe, and the flow velocity in the pipe increases, so as mentioned above, the pressure loss increases, and the pressure drop in the pressure vessel becomes higher than the predetermined injection pressure. Not only is it necessary to increase the original pressure, but pressure pulsations within the injection pipe can cause the pressure inside the injection pipe to become abnormally high or low, creating a risk of damage to the injection pipe and joints. There is a problem that irregular injection such as tertiary injection occurs. 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-mentioned problem, there is a prior art that employs a pressure increasing structure using a booster applying Pascal's principle as a means for increasing the fuel injection pressure to an ultra-high 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, the required injection amount of fuel with an injection pressure of 1500Kg/cm ² is
If the injection time is 10ms and the injection time is 15ml, then if the pressure increase ratio is 7, then by simple calculation, approximately 214Kg/ ^cm2 of hydraulic oil will be
This means that only 105ml needs to be supplied within ms. Since 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, the flow rate of the pressure oil through the solenoid valve is about 630/min.

Direct-acting type solenoid valves use electromagnetic force to move the spool to switch the pressure oil flow path. Direct-acting type solenoid valves use 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 rates, the pilot type is usually used because the direct acting type would be unable to switch due to the fluid force acting on the spool during the switching operation. However, in the case of a pilot type, there is a limit to how fast response can be achieved due to its structure, since it requires multiple steps of operation. On the other hand, the control accuracy 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, the time accuracy is extremely small, 0.3 to 0.7 ms.
Therefore, with the current technology, it is impossible 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.

Purpose: In view of the problems of the prior art described above, the present invention provides a solenoid valve that controls a large flow of pressure oil to be fed to a booster with a pressure increase structure required to increase the pressure of fuel to an ultra-high pressure, and a highly accurate fuel for an internal combustion engine. This problem is solved by sharing the fuel injection function with a small-flow solenoid valve that performs injection control, without stopping the internal combustion engine, and without depending on the rotational speed of the internal combustion engine. First, fuel injection timing and fuel injection amount,
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.

The present invention supplies hydraulic oil from the first pressure source 1 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 second pressure source 2 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.
The fuel oil from the pressure chamber 10 is introduced via the check valve 13 and 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 introduced from the first passage 22 to the control valve 31. The fuel is injected from the nozzle hole 51 via the second passage 35, and the injection valve body 47 facing the fuel reservoir 48 connected to the second passage 35 is attached to the nozzle hole 51 in the closing direction by the spring force of the valve spring 46. The control valve 31 has a valve element 31a provided in a pressure chamber 34 communicating with the second passage 35 seated on a seat surface 32 provided between the first passage 22 and the second passage 35. The valve body 31a is provided with an annular groove 33, and a second
When the control valve 31 is closed, the third passage 36 is opened through the annular groove 33 and oil is drained from the passage 35.
When the valve 1 is opened, the third passage 36 is closed, and the valve body 31a receives pressure from the control piston 37 through the second electromagnetic valve 6 from the first pressure source 1.
1, the control piston 3
This fuel injection control device for an internal combustion engine is characterized in that a valve body 31a connected to a valve 7 is pilot operated in a closing direction.

Embodiments Embodiments of the present invention will be described with reference to the drawings. 1st
The figure is a configuration 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 via the conduit 55, the check valve 17, and the first electromagnetic valve 5, and is connected to the pressure chamber 9 by the conduit 43 branching from the conduit 55. Connection port 3 of fuel injection valve 4 via check valve 42 and second solenoid valve 6
9 can be connected to the pressure chamber 38 via a passage 41. The conduits 15, 43 are provided with accumulators 18, 44 for absorbing pressure pulsations within the conduits.
is connected. The second pressure source 2 is connected to the pressure chamber 10 via a conduit 27 from the connection 21 of the booster 3 via a spring-loaded check valve 13 .

Inside the booster 3, a piston 7 that slides on an upper cylinder 66 and a plunger 8 that slides on a lower cylinder 67 are disposed, and the piston 7 and the plunger 8 are pressed against each other. Hydraulic oil supplied from the first pressure source 1 is supplied to 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, through the first solenoid valve 5. It is now available to 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 source 2 via the check valve 13 as described above. is becoming available. The pressure chamber 10 is connected to a pressure accumulation chamber 12 disposed below the booster 3 via a check valve 11 with a spring. The pressure accumulation chamber 12 is connected to 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. A pressure chamber 38 formed on the opposite side of the control valve 31 by the cylinder 68 and the surface 73 of the control piston 37 is filled with hydraulic oil supplied from the first pressure source 1 via the connection port 39. . The valve part B includes an injection valve body 47 that slides on the cylinder 70 and a nozzle hole 51 that connects the injection valve body 47 to the nozzle hole 51.
Valve spring 46 biased in the direction of pressing against the seat surface 50 of
is provided.

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 oil whose pressure is regulated by the pressure regulating valve 57 is supplied to the conduit 55 via the filter 56.

In the second pressure source 2 , fuel oil is increased in pressure from the tank 65 through the filter 64 by the pump 63 , and the pressure oil whose pressure is regulated by the pressure regulating valve 62 is supplied to the conduit 27 .

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 larger, this pressure chamber 23 is moved from the passage 76 to the conduit 2.
Connects to 9. The valve body 31a of the control valve 31 is the seat surface 3
2 and the valve is in the closed state, the passage 36 is connected to the tank 65 from the connection port 52 via the drain pipes 53 and 54 by the annular groove 33 formed in the valve body 31a.
communicate with. 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.

When the left-hand solenoid of the first solenoid valve 5 is energized and in position 5b, the throttle valve 6 with respect to the pressure chamber 9
The flow path is switched so that the connection port 19 of the booster 3 is communicated with the tank 61 via the return conduit 16 in which the 0 is interposed. 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, With that pressure, plunger 8 and piston 7
is pushed up in a direction to reduce 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 pressurized by the pump 63. The impact force at the end of the stroke is alleviated.

The second electromagnetic valve 6 switches the flow path so that the connection port 39 of the pressure chamber 38 communicates with the conduit 43 when the left solenoid is energized and is in position 6b. 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 its driving force causes the control piston 37 to move to the first
The valve body 3 of the control valve 31 is biased to the left in the figure.
1a is a seat surface 32 facing the valve body 31a of the control section A
The connection port 22 and the passage 35 are closed off by the control valve 31.

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, from the passage 76 by a safety valve 80, and from the passage 35 by a control valve 31. .

A passage 36 that branches off from the middle of the passage 35 of the fuel injection valve 4 is connected from the connection port 52 to the drain pipe 5 by an annular groove 35 formed in the valve body 31a of the control valve 31.
It communicates with a tank 65 via 3 and 54. The control valve 31, the pressure chamber 34, the passages 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 valve 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 period W2 is from time t1 to t4 as shown in FIG.
When the flow path of the first electromagnetic valve 5 is switched to position 5a, the conduit 15 and the connection port 19 communicate with each other, and pressure oil is supplied from the first pressure source 1 to the pressure chamber 9. Therefore, the piston 7 and the plunger 8 are pushed downward in FIG. 1, compressing the fuel filling the pressure chamber 10. At this time, the accumulator 18 effectively works to prevent the pressure of the pressure oil within the conduit 15 from dropping momentarily. If the area ratio of the top surface 71 of the piston 7 to the surface 72 of the plunger 8 is K (K>1), a pressure K times the pressure of the pressure chamber 9 is generated in the pressure chamber 10 . K is called the pressure increase ratio. At this time, the control valve 31 is in the cutoff state, so 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 at position 6b, and the area ratio between the valve body 31a and the control piston 37 is
The pressure chamber 38 that acts on the surface 73 of the piston 37 is stronger than the driving force in the valve opening direction due to the pressure of the connection port 22.
is selected so that the driving force in the valve closing direction due to the pressure is sufficiently large. Therefore, the control valve 31 remains closed.

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 6.
a, the connection port 39 communicates with the return conduit 45, and the pressure oil in the pressure chamber 38 is discharged to the tank 61. Therefore, due to the driving force of the pressure oil from the connection port 22 side,
The control valve 31 opens between times t2 and t3 in FIG. As the valve body 31a moves to the right in FIG. 1 in the valve opening direction, the sliding surface of the control valve 31 causes the cylinder 6 to
9 and the passage 52 are cut off, the passage 22 and the pressure chamber 34 communicate with each other, and high-pressure fuel oil flows into the passage 35 from the pressure accumulation chamber 12. As a result, the pressure within the pressure chamber 48 increases, and the driving force acting on the stepped portion 75 of the injection valve 47 overcomes the spring force of the valve spring 46 biasing the injection valve 47 in the valve closing direction. The valve is opened and high pressure fuel is injected from the nozzle hole 51.

After the injection starts, fuel is supplied and discharged from the pressure accumulation chamber 12 to the nozzle hole 51 via the passage 35, and at the same time, the check valve 11 is opened and the pressure accumulation 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 moved to position 6b so that the connection port 39 and the conduit 43 communicate with each other.
Switch to. 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 closing direction by the driving force of the control piston 37, and the valve body 31a is pressed against the valve seat 32, thereby blocking the connection port 22 from the passage 35. At this time, as the valve body 31a moves in the valve closing direction, the passage 36 and the connection port 52 are brought into communication by the annular groove 33, so that the high-pressure fuel oil filling the passage 35 flows into the drain pipes 53, 54. is discharged and the pressure drops rapidly. As a result, fuel storage 4
At 8, the driving force acting on the injection valve 47 in the valve opening direction instantly becomes smaller, and the injection valve 47 is urged in the valve closing direction by the spring force of the valve spring 46 in the valve closing direction, and the valve seat 50 The tip 49 of the injection valve 47 is pressed to close the valve. Therefore, fuel injection from the nozzle hole 51 is completed. The drained oil from the annular groove 33 is
It helps to improve the so-called "fuel shortage",
Effective in improving fuel efficiency.

The stroke of the control piston 37 is very small, for example on the order of 1 mm. Therefore, the second
The flow rate of hydraulic oil passing through the solenoid valve 6 is small. Therefore, the driving force required by the hydraulic oil is small and a direct-acting solenoid valve can be used. This makes it possible to improve the accuracy of injection timing and adjustment.

When valve part B is closed, pressure accumulator chamber 12 and pressure chamber 1
At zero, high pressure is instantaneously generated due to the acceleration of the piston 7 and 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. In other words, the pressure chamber 23 acts as a buffer volume due to some abnormality and the piston 1
4 moves downward in Figure 1 by more than a certain value,
Passage 76 communicates with pressure chamber 23 and high pressure fuel is discharged from conduit 29 into tank 65 . Therefore, the pressure accumulation chamber 12 is prevented from becoming abnormally high pressure. As the pressure in the pressure storage chamber 12 is equalized as the piston 7 and plunger 8 stop, the piston 1
4 is pushed back by spring 25.

After the fuel injection ends, at time t4 in FIG. The pressure oil is discharged from the return conduit 16 via a throttle valve 60 into a tank 61 . 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 1
Since it is cut off from the pressure accumulation chamber 12 by 1,
High pressure is maintained in the pressure accumulation chamber 12 . Pressure chamber 10
When the pressure at the connecting port 21 becomes lower than the pressure at the connection port 21 by the cracking pressure of the check valve 13, the check valve 13 opens, high-pressure fuel is replenished from the second pressure source, and the piston top surface 71 is brought into contact with the seat of the cylinder 66. It is pressed against the surface 74 and stops. The opening degree of the throttle valve 60 disposed midway through the return conduit 16 is adjusted so as to limit the movement 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 electromagnetic valve 5 is large because the pressure increase ratio is large to improve combustion performance and a large injection amount is produced in a short period of time.
When injecting 11 c.c. of fuel at a crank angle of 25 degrees at a rotation speed of 500 rpm, and the pressure increase ratio is 8, Q = 6 x 500/25 x 11 x 60/1000 x 8 = 633/min... ( 1) For this reason, the first solenoid valve 5 has to be pilot operated, and although pilot operated solenoid valves have poor response, the pressure chamber 10 can be refilled with fuel within a sufficiently long period of time other than the injection period. You can do it in the first step.
Switching of the solenoid valve 5 does not require high speed as in the case of the second solenoid valve 6. In fact, in an internal combustion engine that rotates at 500 rpm, the injection period and injection timing are adjusted by 1 crank angle.
When controlling in degree units, the second solenoid valve 6 is required to have a response of 1000/500×6=0.33ms (2), but if the first solenoid valve 5 has an injection timing of 25 degrees, ( 360-25) x 1000/500 x 6 = 112 ms... (3) Since it is only necessary to switch the flow path and replenish fuel to the pressure chamber 10, the response is 1/10 compared to the second solenoid valve 6.
The following is fine.

In the embodiment configured as described above, ultra-high pressure fuel is accumulated for each injection cycle,
Since the booster 3 acts to constantly replenish fuel within the injection period, a stable injection rate can be obtained. A large-capacity ultra-high-pressure pressure vessel is not required.

Since the booster 3, which is a pressure accumulating container, can be miniaturized, the booster 3 can be placed close to or directly connected to the injection valve 4. Therefore, the pressure accumulation chamber 1 which is a pressure vessel
The injection passage from the injection valve 2 to the injection valve 4 can be shortened, and the pressure loss in the injection passage can be reduced.
Furthermore, 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 source to the booster, so conventional piping joints can be used and are inexpensive.

In conventional hydraulically actuated pressure booster fuel injection devices, the impact force generated when the booster piston or plunger is seated has been a problem, but in the case of the present invention, the pressure increaser has a shock absorbing piston disposed in the pressure accumulation chamber 12 and Piston 14 constituting a safety valve
This makes it possible to prevent overpressure in the pressure accumulation chamber 12.

By disposing the check valves 11 and 13 in the pressure accumulation 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 in the past, injection timing control, which requires extremely high control accuracy in both response and repeatability, was performed using a single unit. Since this is done using a solenoid valve, it is not compatible to achieve large capacity and accuracy at the same time. In the present invention, fuel injection by hydraulic operation can be achieved by having individual electromagnetic 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.

Since a booster 3 and an injection valve 4 are provided for each cylinder, and the injection system is independent for each cylinder, it is possible to prevent interference between cylinders like in a high-pressure injection system, and this configuration for one cylinder also prevents failure. Even if
Since the internal combustion engine can continue to operate in other cylinders, the reliability of the engine is high.

Since the fuel injection valve 4 is constructed by integrally combining the control section A and the valve section B, 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 shown in FIGS. 1 and 2, and corresponding parts are provided with the same reference numerals. What should be noted is that due to the pressure of the fuel in the pressure accumulation chamber 12, the stepped portion of the valve body 31a of the control valve 31 has a
The valve is configured so that an upward force as shown in FIG. 3 acts to open the valve.

As yet another embodiment of the present invention, a throttle valve 60
Instead of intervening in the conduit 16, it may be interposed in the conduit 27.

FIG. 4 is a configuration 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 a four-way valve is used as the second electromagnetic valve 6, and the pressure chambers 38a and 38b, which have the first pressure receiving surface 100 and the second pressure receiving surface 101 arranged on both sides of the control piston 37, are the second solenoid valve 6. The solenoid valve 6 can be connected alternately to the pressurized conduit 43 and the relief conduit 45, so that the control piston 37 is urged to the right in the switching position 6a and to the left in the switching position 6b. In the fourth illustration, the first solenoid valve 5 is at the switching position 5a, the second solenoid valve 6 is at the switching position 6b, and the times t1 and t in FIG.
It shows a state between 2. 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 of the fuel oil that urges the control valve 31 to the right through the passage 22 is smaller than the force of the hydraulic oil that urges the control piston 37 to the left.
1 is closed. Therefore, the pressure in the passage 35 is released to the tank, and the valve body 47 is biased by the spring 46 and closed. At time t2, the second solenoid valve 6
is switched to the state shown in 6a, the pressure chamber 3
The pressure conduit 43 is connected to the pressure chamber 8a, and the relief conduit 45 is connected to the pressure chamber 38b, and the control piston 37 is urged to the right, so the control valve 31 moves to the right and the pressure accumulation chamber 1
2 flows from passage 22 to fuel reservoir 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 electromagnetic valve 6 is switched again and enters the state shown in the fourth figure, and the control valve 31 moves to the left and is closed, 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 that a four-way valve is used as the second electromagnetic valve 6, and the pressure chamber 3 has a first pressure receiving surface 100 and a second pressure receiving surface 101 arranged on both sides of the control piston 37.
8a and 38b can be connected alternately to the pressured conduit 43 and the relief conduit 45 by the second solenoid valve 6, and the control piston 37 moves upward in the switching position 6a and downward in the switching position 6b. Each is energized. The fifth illustration shows a state in which the first solenoid valve 5 is at the switching position 5a and the second solenoid valve is at the switching position 6b, between times t1 and t2 in FIG. 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 B is closed. That is, the force of the fuel oil that urges the control valve 31 upward through the passage 22 is smaller than the force of the hydraulic oil that urges the control piston 37 downward, and the control valve 31 is closed. Therefore, the pressure in the passage 35 is released to the tank, and the valve body 47 is biased by the spring 46 and closed. When the second electromagnetic valve 6 is switched to the state shown in 6a at time t2, the pressure conduit 43 is connected to the pressure chamber 38a and the relief conduit 45 is connected to the pressure chamber 38b, and the control piston 37 is urged upward, so that the control Valve 31 moves upwards and fuel in accumulator chamber 12 flows from passage 22 to fuel reservoir 48 . Valve body 47
is urged by the fuel pressure and rises against the resistance of the spring 46, and injection is performed into a cylinder chamber (not shown). At time t3, the second electromagnetic valve 6 is switched again to the state shown in FIG. 5, and the control valve 31 is moved downward and 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 stopping the internal combustion engine and without depending on the rotational speed of the internal combustion engine. It becomes possible to increase the pressure.

In particular, according to the invention, the injection valve body 47 is connected to the valve spring 4
6 in the direction of closing the nozzle hole 51, and at the end of fuel injection, the hydraulic oil from the second solenoid valve 6 blocks off the fuel oil from the pressure accumulation chamber 12, and the fuel in the fuel reservoir 48 The oil is drained from the second passage 35 through the annular groove 33 and from the third passage 36, so that fuel runs out easily and it becomes possible to supply fuel oil only for a desired period. Moreover, such a configuration is simple and easy to implement.

[Brief explanation of the drawing]

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 configuration diagram of still another embodiment of the present invention, and FIG.
The figure is a configuration diagram of another embodiment of the present invention. 1...First pressure source, 2...Second pressure source, 3...
Booster, 4... Fuel injection valve, 5, 6... Solenoid valve, 7... Piston, 8... Plunger, 10...
... Pressure chamber, 11, 13 ... Check valve, 12 ... Pressure accumulation chamber, 31 ... Control valve, 35 ... Passage, 51 ... Nozzle hole, A ... Control section, B ... Valve section.

Claims (1)

[Scope of Claims] 1. Hydraulic oil from the first pressure source 1 is supplied to the movable bodies 7, 8 in the booster 3 via the first solenoid valve 5, which remains open for at least a period W2 that is longer than the fuel injection period W1. The pressure chamber 1 is guided to the large-diameter pressure-receiving surface 71 side at one end, and the pressure chamber 1 is guided to the small-diameter pressure-receiving surface 72 side at the other end of the movable bodies 7 and 8.
0, fuel oil is supplied from the second pressure source 2 to the first check valve 1.
3, the fuel oil from the pressure chamber 10 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 introduced from the first passage 22 to the control valve 31 and the second check valve 11. The fuel is injected from the nozzle hole 51 through the passage 35, and the injection valve body 47 facing the fuel reservoir 48 connected to the second passage 35 is biased in the closing direction by the spring force of the valve spring 46. The control valve 31 can be closed by seating a valve body 31a provided in a pressure chamber 34 communicating with the second passage 35 on a seat surface 32 provided between the first passage 22 and the second passage 35. The valve body 31a is provided with an annular groove 33, and a second
When the control valve 31 is closed, the third passage 36 is opened through the annular groove 33 and oil is drained from the passage 35.
When the valve 1 is opened, the third passage 36 is closed, and the valve body 31a receives pressure from the control piston 37 through the second electromagnetic valve 6 from the first pressure source 1.
1, the control piston 3
A fuel injection control device for an internal combustion engine, characterized in that a valve body 31a coupled to a valve body 31a is pilot operated in a closing direction.