JP3353188B2 - Fuel injection engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection engine mounted on, for example, an automobile.

[0002]

2. Description of the Related Art Some conventional fuel injection engines pressurize a fuel supplied by a low pressure pump by a high pressure fuel pump and inject the fuel into each cylinder from injectors respectively arranged in a plurality of cylinder heads. .

As described above, by using the high-pressure fuel pump, the fuel pipe between the pressurized fuel and the injector is shortened, so that the responsiveness is improved.

[0004]

However, fuel pipes for supplying fuel from the high-pressure fuel pump to the respective injectors are required by the number of injectors, and the fuel pipes are complicated and costly.

[0005] Further, since the fuel pipe is separated from the cylinder head, the high-pressure fuel is not heated, so that the vaporization after being injected into the cylinder is not improved by that much, and the performance cannot be sufficiently brought out. There are cases where the unburned gas component cannot be sufficiently reduced.

An object of the present invention is to provide a fuel injection engine which has a simple structure, is inexpensive, and has improved vaporization after being injected.

[0007]

In order to solve the above problems and achieve the object, the invention according to claim 1 supplies fuel in a fuel tank by a low pressure pump, and supplies the fuel by a high pressure fuel pump. In a fuel injection type engine that is pressurized and injected into each cylinder from an injector disposed in each of a plurality of cylinder heads, a pressurized fuel supply path is formed in the cylinder head. Each injector communicates within the cylinder head, and connects the pressurized fuel supply path and the high-pressure fuel pump. An accumulator is disposed between the pressurized fuel supply path and the high-pressure fuel pump. A fuel pressure actuator for increasing or decreasing the pressure is provided. The fuel pressure actuator has a pressure chamber whose volume is variable by a piston, and pressure communication between the pressure chamber and the accumulator is performed. The accumulator chamber is pressurized when the engine is started, and depressurized when the engine is stopped. A sub-tank with a partition having a maze formed by a partition is provided in the fuel tank, and an upper opening of the maze of the sub-tank with the partition is provided. The fuel is returned from the accumulator under the control of a high-pressure regulator, and can be supplied into the fuel tank from the lower opening of the maze.

According to a second aspect of the present invention, in the fuel injection engine, the high-pressure regulator is disposed in the accumulator, and is opened when the pressure in the accumulator becomes equal to or higher than a predetermined value, and fuel is supplied to the maze of the sub-tank with the partition plate. It is characterized by returning to the upper part.

[0009]

A fuel injection engine according to a third aspect of the present invention is characterized in that a pressure accumulating chamber is formed in the cylinder head.

[0011]

According to the first aspect of the present invention, since the pressurized fuel supply passage is formed in the cylinder head, the connecting structure between each injector and the high-pressure fuel pump is simple and inexpensive.
In addition, a pressurized fuel supply passage is formed in the cylinder head, and the pressurized fuel supply passage and each injector communicate with each other in the cylinder head, so that the high-pressure fuel is heated by the cylinder head and injected into the cylinder accordingly. It is possible to improve the vaporization after the gas is burned, to bring out the performance sufficiently, or to sufficiently reduce the unburned gas component. In addition, a pressure accumulation chamber is arranged between the pressurized fuel supply path and the high-pressure fuel pump,
The pressure in the accumulator is increased by the fuel pressure actuator when the engine is started and reduced when the engine is stopped. Also,
The fuel is returned from the accumulator to the upper part of the maze of the sub tank with a partition plate provided in the fuel tank by the control of the high pressure regulator,
By supplying the fuel into the fuel tank through the opening in the lower part of the maze, it is possible to remove bubbles from the return fuel, and air bubbles at the upstream of the high-pressure fuel pump, such as bubbles generated when returning from the high-pressure side and vapor at the low-pressure part As a result, irregular bubbles do not exist, and stable fuel supply becomes possible, and stable engine performance is obtained.

According to the second aspect of the present invention, the high-pressure regulator is disposed in the accumulator, and is opened when the pressure of the accumulator becomes a predetermined level or more, and the fuel is returned to the upper part of the maze of the sub-tank with the partition plate. Can be adjusted with a simple structure using a single high-pressure regulator.

[0013]

According to the third aspect of the present invention, the pressure accumulating chamber is formed in the cylinder head, the connection structure between the pressure accumulating chamber and the pressurized fuel supply passage is simple, and the high pressure fuel is more effectively heated by the cylinder head. Accordingly, the vaporization after being injected into the cylinder can be improved, and the performance can be sufficiently obtained, or the unburned gas component can be sufficiently reduced.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a fuel injection engine according to the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram of a fuel injection system. A fuel pump 34 is disposed in the fuel tank 33, and the first to third injectors 3 are provided to the fuel injection engine 7 in accordance with each cylinder.
60 to 362 are attached. The fuel 31 discharged from the fuel pump 34 is supplied to the first fuel supply pipe 200, the high-pressure fuel pump 201, the second fuel supply pipe 202, and the accumulator 20.
3. The first to third via the pressurized fuel supply passages 204 to 206
The fuel is supplied to the injectors 360 to 362 sequentially. A fuel filter 207 is interposed in the middle of the first fuel supply pipe 200.

The high pressure fuel pump 201 includes a first check valve 40
0, a second check valve 401, a plunger 402, a spring 403, a cam 404, a drive shaft 261 and a driven sprocket 262. A plunger 402 is disposed between the first check valve 400 and the second check valve 401, and the spring 403 always urges the plunger 402 in a direction to contact the cam 404. The driven sprocket 262 is rotated by the chain 263, and in conjunction with this, the drive shaft 261 is rotated.
The rotation of the spin. The rotation of the drive shaft 261 causes the cam 40 to rotate.
4 rotates in conjunction with each other, and the plunger 402 is pushed by the cam 404 to reciprocate. When the plunger 402 moves forward by being pushed by the cam 404, the first check valve 400 is closed, the second check valve 401 is opened, and the fuel 31 is supplied through the second fuel supply pipe 202. When the cam 404 is no longer pushed and the plunger 402 moves backward by the spring force of the spring 403, the first check valve 400 opens, the second check valve 401 closes, and the fuel 31 discharged from the fuel pump 34 is sucked. As described above, the first check valve 401 and the second check valve 402 are opened and closed by the reciprocating movement of the plunger 402, and the pressure of the fuel 31 supplied from the fuel pump 34 is increased to disconnect the second fuel supply pipe 202. To the accumulator 203 via

The fuel injection system includes a low-pressure regulator 5
When the pressure between the discharge port 34a of the fuel pump 34 and the suction port 34b of the high-pressure fuel pump 201 is equal to or higher than a predetermined value, the low-pressure regulator 500 supplies the fuel discharged from the fuel pump 34 to the first The fuel is returned to the fuel tank 33 upstream of the fuel pump 34 via the fuel return pipe 208. The low-pressure regulator 500 is provided with a higher portion in the middle of the first fuel supply pipe 200 that connects the discharge port 34a of the fuel pump 34 and the suction port 34b of the high-pressure fuel pump 201, and is disposed at this higher portion.

A fuel pressure sensor 600 is provided in a pressure accumulating chamber 203 disposed between the high-pressure fuel pump 201 and the first to third injectors 360 to 362, and a fuel tank 33 is provided from the pressure accumulating chamber 203 based on fuel pressure data. A high-pressure regulator 601 for bypassing fuel via the second fuel return pipe 210 is provided. Fuel pressure sensor 60
Fuel pressure data from zero is sent to the controller 602. The control device 602 has the accelerator position data from the accelerator position detecting means 603 and the engine speed detecting means 6.
Engine speed data from step 04 is input. The control device 602 controls the first to third injectors 36 based on accelerator position data or engine speed data, or based on accelerator position data and engine speed data.
0 to 362 are controlled. For example, when the engine speed is high or the accelerator position is high load, or when the engine speed is high or the accelerator position is high load, the amount of fuel injection from the first to third injectors 360 to 362 is increased. Further, the control device 602 controls the high-pressure regulator 601 based on the fuel pressure data, and causes the fuel to bypass from the accumulator 203 to the fuel tank 33 via the second fuel return pipe 210.

FIG. 2 is a sectional view of the cylinder top of the fuel injection type engine, FIG. 3 is a plan view of the cylinder head, and FIG. 4 is a plan view showing a state of being mounted on an automobile. This automobile 1 has a vehicle body 2, a vehicle body frame 3, left and right front wheels 4, 4 and left and right rear wheels 5, 5. In the drawings, the arrow Fr indicates the front of the automobile 1, and the left and right refer to the direction toward the front unless otherwise specified.

A fuel injection engine 7 is disposed at the front of the vehicle body 2.
It is supported by. The fuel injection type engine 7 includes first to third
This is a parallel three-cylinder pre-compression type two-stroke engine having cylinders 10 to 12. A power transmission device 13 is connected to the left end of the fuel injection engine 7, and the power of the fuel injection engine 7 is transmitted to at least one of the front wheels 4 and the rear wheels 5 via the power transmission device 13, and the automobile 1 runs. It is possible.

An intake manifold 15 is provided on the rear surface of the fuel injection engine 7 when viewed from the front, and a throttle valve 16 is attached to an end of the intake manifold 15. On the other hand, an air cleaner 17 is disposed on the upper left side of the fuel injection engine 7, and a first intake pipe 18 extends forward from the air cleaner 17, and a throttle valve 1 is provided.
6 and the air cleaner 17 are connected by a second intake pipe 19. An airflow sensor 20 is arranged in the second intake pipe 19. When the fuel injection engine 7 is driven, air flows into the first intake pipe 18, the air cleaner 17, and the second intake pipe 1.
9. The fuel is drawn into the fuel injection engine 7 through the throttle valve 16 and the intake manifold 15 in order.

An exhaust manifold 21 is provided on a front surface of the fuel injection engine 7. Exhaust manifold 21
The front end of the first exhaust pipe 22 is connected to the end of the first exhaust pipe 22.
The exhaust pipe 22 extends rearward below the fuel injection engine 7. A catalyst pipe 23, a first muffler 24, and second mufflers 25, 25 are sequentially connected to a rear end of the first exhaust pipe 22. Further, the second exhaust pipe 2 is provided at the rear end of the second muffler 25.
6 and the third muffler 27 are sequentially connected. Further, a branch pipe 28 is provided from a middle part of the second exhaust pipe 26 to the left side. Exhaust gas generated by the combustion is exhaust manifold 21, first exhaust pipe 22, catalyst pipe 23, first muffler 2
4. Second muffler 25, second exhaust pipe 26 and third muffler 2
7 sequentially.

The fuel injection type engine 7 is provided with a fuel supply device 32 for supplying fuel. Fuel supply device 32
Has a fuel tank 33 provided at the rear of the vehicle body 2, and an electric fuel pump 34 is disposed in the fuel tank 33.

FIGS. 2 and 3 show the fuel injection type engine 7.
As shown in the figure, a cylinder head 51 is mounted on a cylinder block 50, and a piston 5 is provided in a cylinder 52 in the cylinder block 50 according to the first to third cylinders 10 to 12.
3 is provided so as to be able to reciprocate. Cylinder block 5
At 0, a scavenging passage 54 and an exhaust passage 55 are formed, and the piston 53 is opened and closed by reciprocating motion.

A rotary exhaust timing variable valve 56 for varying the exhaust timing is provided near the cylinder side opening of the exhaust passage 55, and the rotary exhaust timing variable valve 56 is driven according to the engine speed to set the exhaust timing. Control.

A combustion chamber 57 is formed by the cylinder block 50, the head of the piston 53 and the cylinder head 51, and the cylinder head 51 has first to third spark plugs 370 to 372 and first to third ignition plugs corresponding to the cylinders 10 to 12. Third injectors 360 to 362 are attached so as to face the respective combustion chambers 57. A water jacket 60, a water jacket 60,
61 are formed, and the water jackets 60 and 61 communicate with each other.

First to third pressurized fuel supply passages 204 to 206 are formed in the cylinder head 51, and the first to third pressurized fuel supply passages 204 to 206 and the first to third injectors 360 to 360 are formed. 362 communicate with each other in the cylinder head 51. Further, the first to third pressurized fuel supply paths 20
4 to 206 are connected to a high-pressure fuel pump 201 via a pressure accumulating chamber 203. As shown in FIGS. 2 and 3, the accumulator chamber 203 includes first to third cylinders 1 in the cylinder head 51.
An aluminum pipe 203a is formed by casting from 0 to 12, and the pressure accumulating chamber 203 is disposed between the first to third pressurized fuel supply paths 204 to 206 and the high-pressure fuel pump 201. The accumulator 203 has an aluminum pipe 203a
Are communicated with the first to third pressurized fuel supply passages 204 to 206 through the holes 203b to 203d formed in the holes.

At one end of the accumulator 203, a high-pressure regulator 601 is disposed.
Is opened when the pressure of the accumulator 203 becomes equal to or higher than a predetermined value,
The fuel is returned to the fuel tank 33 via the second fuel return pipe 210, and thereby the fuel is returned to the upstream side of the high-pressure fuel pump.

The fuel discharged from the fuel pump 34 disposed in the fuel tank 33 is supplied to the first fuel supply pipe 200, the high-pressure fuel pump 201, the second fuel supply pipe 202,
03, first to third injectors 360 to 3 of first to third cylinders 10 to 12 via pressurized fuel supply paths 204 to 206
62. By using the high-pressure fuel pump 201, the pressurized fuel and the first to third injectors 360
362 is shortened, and as a result, the responsiveness is improved.

A fuel filter 207 is provided in the middle of the first fuel supply pipe 200. High pressure fuel pump 201
Has a built-in low-pressure regulator. When the pressure between the discharge port of the fuel pump 34 and the high-pressure fuel pump 201 is equal to or higher than a predetermined value, the fuel discharged from the fuel pump 34 is
The fuel is returned into the fuel tank 33 upstream of the fuel pump 34 via the fuel return pipe 208 and the second fuel return pipe 210. The high-pressure fuel pump 201 has a vacuum pump 209 for braking.
Are arranged integrally.

The fuel from the high-pressure fuel pump 201 is accumulated in the accumulator 203, and the first to third injectors 360 to 360 are stored.
362. An electronic control regulator is built in the accumulator 203, and the electronic control regulator is connected to the accumulator 20.
When the pressure of No. 3 becomes equal to or higher than a predetermined value, the fuel is controlled to return to the fuel tank 33 on the upstream side of the high-pressure fuel pump 201 via the second fuel return pipe 210.

The fuel 31 supplied through the first fuel supply pipe 200 by the low-pressure fuel pump 34 is pressurized by the operation of the high-pressure fuel pump 201, and the pressure fuel is supplied to the second fuel supply pipe 20.
2 to the accumulator 203, accumulates pressurized fuel in the accumulator 203, and injects it into each cylinder from the first to third injectors 360 to 362 via the first to third fuel supply paths 204 to 206. These are the first to third spark plugs 370 to 372
And is provided for combustion.

The fuel injection type engine 7 is provided with a lubricating device 60 for supplying lubricating oil. This lubricating device 60
Has an oil pump 61 that supplies lubricating oil to a predetermined portion, and an oil tank 62 that stores the lubricating oil and supplies the lubricating oil to the oil pump 61.

As described above, in the cylinder head 51, the first
To form third pressurized fuel supply paths 204 to 206,
Third pressurized fuel supply paths 204 to 206 and high pressure fuel pump 2
01 is connected, and the first to third injectors 360 to 362 and the high pressure fuel pump 201 are connected by forming the first to third pressurized fuel supply paths 204 to 206 in the cylinder head 51. Simple and inexpensive.

The first to third cylinder heads 51 are provided in the cylinder head 51.
Since the pressurized fuel supply passages 204 to 206 are formed and the first to third pressurized fuel supply passages 204 to 206 and the first to third injectors 360 to 362 communicate with each other in the cylinder head 51, Is heated by the cylinder head 51, and the vaporization after being injected into the cylinder can be improved accordingly, the performance can be sufficiently obtained, or the unburned gas component can be sufficiently reduced.

The first to third pressurized fuel supply paths 204 to
A pressure accumulating chamber 203 is arranged between the high pressure fuel pump 201 and the high pressure fuel pump 201. When the pressure in the pressure accumulating chamber 203 becomes equal to or higher than a predetermined value, the pressure accumulating chamber 203 is opened. And the first to third
The fuel pressure to the injectors 360 to 362 can be adjusted with a simple structure using a single high-pressure regulator 601.

Further, the pressure accumulating chamber 203 is
1, the connection structure between the pressure accumulating chamber 203 and the first to third pressurized fuel supply passages 204 to 206 is simple, and the high-pressure fuel is more effectively heated by the cylinder head 51. Can be improved and the performance can be sufficiently brought out, or the unburned gas component can be sufficiently reduced.

Next, the fuel tank 33 provided at the rear of the vehicle body 2 will be described. 5 is a cross-sectional view of the fuel tank, FIG. 6 is a cross-sectional view taken along the line VI-VI of FIG. 5, and FIG.
It is sectional drawing which follows the II-VII line.

A sub-tank 300 with a partition plate is provided in the fuel tank 33, and a second fuel return pipe 210 is connected to the sub-tank 300 with a partition plate to return fuel into the sub-tank 300 with a partition plate. A maze 302 is formed by a partition plate 301 inside the sub-tank 300 with a partition plate, and an opening 302 of the maze 302 is formed.
a is facing inward. The sub-tank 300 with a partition plate prevents the generation of bubbles due to the return fuel by the maze 302. In addition, a cooling fin 303 is formed below the sub-tank 300 with a partition plate.
Reference numeral 03 protrudes downward from the lower part of the fuel tank 300 and comes into contact with air.

A pump mounting cap 304 is provided on the bottom 33a of the fuel tank 33, and a fuel pump 34 is supported on a support portion 304a of the pump mounting cap 304. A first fuel supply pipe 200 is connected to one side of the fuel pump 34, and suction pipes 305 and 306 are connected to the other side.
Are connected, and the suction ports 3 of the suction pipes 305 and 306 are connected.
05a and 306a are close to the bottom 33a of the fuel tank 33.

In general, when the high-pressure fuel pump 201 is used, when the high-pressure fuel returns to the fuel tank 33, the air melted under the high pressure becomes low pressure and generates bubbles. When these bubbles are sucked up by the low-pressure fuel pump 33, insufficient measurement occurs.

In the fuel tank 33, a sub-tank 300 with a partition plate is arranged.
The return fuel can be defoamed and cooled inside, and bubbles are irregularly present in the upstream part of the high pressure fuel pump, for example, bubbles generated when returning from the high pressure side and bubbles generated by vapor in the low pressure part. And stable fuel supply becomes possible, and stable engine performance is obtained.

Next, control for improving the engine start will be described. FIG. 8 is a fuel injection system including an engine starter, and FIG. 9 is a control timing chart of the engine.

The fuel injection type engine 7 is provided with a fuel pressure actuator 700 as shown in FIG. The fuel pressure actuator 700 includes a piston 701, a rack 703 formed on a rod 702 of the piston 701,
Pinion 704, drive motor 705, pressurizing chamber 706
And a pressure communication passage 707. The drive motor 705 is rotated forward and backward by the control device 602, and the pinion 704 is rotated by the drive motor 705, and the piston 701 moves forward or backward through the rack 703 and the rod 702. By the advance of the piston 701, the pressurizing chamber 70
6 is compressed and passes through the pressure communication passage 707 to the pressure chamber 203.
, While the piston 701 moves backwards,
6 expands and accumulates in the pressure accumulating chamber 203 through the pressure communication passage 707.
Is configured to reduce the pressure.

Next, the starting control of the engine will be described with reference to FIGS. Even if the driver presses the starting cell switch, the cell motor does not operate for a predetermined time T1, for example, about 1 to 2 seconds. Within this predetermined time T1, the drive motor 705 of the fuel pressure actuator 700 rotates to rotate the pinion 704, the piston 701 moves forward through the rack 703 and the rod 702, and the pressurizing chamber 706 is compressed and the pressure communication passage 707 , The fuel pressure in the accumulator 203 is increased. While the movement of the piston 701 is stopped, the starter motor starts rotating after a lapse of a predetermined time T1, and the ignition system, the first to third injectors 360 to 362, and the high-pressure regulator 601 start to operate. I do. First to third injectors 360 to 362
Opens and closes at a predetermined timing to inject fuel. The high-pressure regulator 601 adjusts the pressure of the accumulator 203.

The rotation speed of the starter motor causes the engine speed to rise, and the engine is started by igniting at a predetermined engine speed, and after a short time after the ignition, the starter motor stops rotating and the piston 701 moves to the neutral position. Return.
Although the starter motor stops, the ignition circuit of the ignition system continues to operate, and the engine enters an operating state.

When the operation of the ignition circuit of the ignition system is stopped and the engine is stopped, the drive motor 705 of the fuel pressure actuator 700 rotates in the reverse direction to rotate the pinion 704 in the opposite direction, and the piston 70 moves through the rack 703 and the rod 702.
1 moves backward, the pressurizing chamber 706 expands, and the pressure communication passage 707
, The fuel pressure in the accumulator 203 is reduced. The backward movement of the piston 701 stops, and then the piston 701 moves forward and returns to the neutral position.

As described above, the injector is not operated for several revolutions of the crankshaft until the fuel pressure is sufficiently increased. That is, if the fuel is injected before the fuel pressure is sufficiently increased at the time of starting the engine, atomization is deteriorated and the spark plug and the combustion chamber are contaminated. Further, even if the fuel pressure subsequently increases, the ignitability deteriorates due to fouling. Further, although the CO component is increased in the exhaust gas at the time of starting, these problems are prevented from occurring if the injector is not operated for several revolutions of the crankshaft until the fuel pressure is sufficiently increased.

Next, the first to third injectors 360 to 360
62 will be described, but they are similarly configured. FIG. 10 is a cross-sectional view of the injector, and FIG. 11 is an enlarged cross-sectional view of a distal end portion of the injector.

First to third injectors 360 to 362
Is a substantially cylindrical bottomed upper case 500 opening toward the cylinder head 51 side, a substantially bottomed cylindrical lower case 501 facing the opening of the upper case 500, and upper and lower cases 500 and 501. Valve body 50 mounted inside
2 and is fixed to the cylinder head 51 by fixing bolts 503 penetrating both upper and lower cases.
The upper and lower cases are connected by connecting bolts 504.

The valve body 502 includes a substantially bottomed cylindrical inner case 505 fitted and fixed to the inner peripheral portions of the upper and lower cases.
A nozzle case 506 screwed to the inner peripheral portion of the inner case 505, an electromagnet 507 and a valve rod 508 arranged in the nozzle case 506, and a hollow screw screwed to a shaft center of the upper case 500. It is composed of a fuel passage forming member 509 and the like. The hollow portion of the fuel passage forming member 509 is connected to the first to third pressurized fuel supply passages 204 to 204 through passages not shown.
206.

The nozzle case 506 includes a first to third injectors 360 to 36 that penetrate the bottom of the lower case 501 and protrude toward the cylinder head 51.
The fuel injection nozzle 510 is integrally formed on the same axis as the second axis C, and is fixed to the protruding end of the nozzle mounting cylinder 506a. Further, the fuel injection nozzle 510 is formed in a substantially cylindrical shape, and has a fuel injection port 510a formed in an opening at the tip end. The fuel injection port 510a is configured to face the combustion chamber 57. The space between the fuel injection nozzle 510 and the cylinder head 51 is sealed by a seal ring 520.

A two-dot chain line arrow drawn near the fuel injection port 510a indicates the fuel injection direction. Fuel injection port 5
A groove 510b is provided near 10a so as to surround the fuel injection port 510a. By appropriately setting the width and depth of the groove 510b, the temperature of the nozzle tip can be maintained at a temperature at which the attached carbon is burned off. Further, it is possible to prevent carbon from adhering and accumulating around the fuel injection port 510a and changing the spray shape. Further, the fuel injection port 510
It is possible to prevent carbon from adhering and accumulating in the vicinity of a to reduce the sealing performance of the valve stem 508.

The electromagnet 507 is composed of an upper magnet 507a and a lower magnet 507b fitted to each other from above and below, and a solenoid 511 centered on the axis C is provided inside the upper magnet 507a and the lower magnet 507b. I have. The lead wire (not shown) of the solenoid 511 is connected to the control device 602 via a wiring connector 512 mounted on the upper case 500.
It is connected to the. The upper magnet 507a is welded to the inner bottom surface of the inner case 505, that is, the surface facing the cylinder head 51, and an adjusting screw 513 for adjusting the set load of a return spring (not shown) is screwed to its axial center. Have been. The upper magnet 507a and the lower magnet 50
Circular holes which form a part of the fuel passage and which communicate with the hollow portion of the fuel passage forming member 509 are formed in the axial center portions of the 7b and the adjusting screw 513, respectively.

A cylindrical armature 515 is inserted into a circular hole 514 formed in the axis of the lower magnet 507b so as to be movable in the axial direction. The electromagnet 507 is
When the solenoid 511 is excited, the armature 5
15 is magnetically attracted to the upper magnet 507a. That is, at the time of excitation, the armature 515 moves upward from the state shown in FIG.

The stem 50 of the armature 515
8 are welded at the upper end. Also, armature 51
5 and the adjusting screw 513, the armature 51
Return spring 5 for urging the cylinder 5 toward the cylinder head 51
16 is provided in a compressed state.

The valve valve 508 is formed so as to be narrower than the nozzle mounting cylinder 506a of the nozzle case 506 and the fuel injection nozzle 510 so as to form a gap serving as a fuel passage. A valve body 508a that opens and closes the fuel injection port 510a is formed at the leading end, and a protrusion 508b that extends radially is formed at a portion that extends into the fuel injection nozzle 510. This projection 50
8 b is configured to be slidable in the axial direction with respect to the inner wall surface of the hollow hole of the fuel injection nozzle 510. That is, the valve stem 508
One end is movably supported along the axial direction by an inner case 505 having an electromagnet 507 via an armature 515, and the other end is freely movable along an axial direction to a nozzle case 506 via a fuel injection nozzle 510. Will be supported. Also, the armature 515 in the valve stem 508
The fuel passage in the electromagnet 507, that is, the circular hole in the axial center of the upper magnet 507a and the nozzle case 5
A fuel passage 508c communicating with the inner peripheral space of the fuel cell 06 is formed.

According to the first to third injectors 360 to 362 thus configured, the armature 515 is excited by exciting the solenoid 511 of the electromagnet 507.
Moves upward from the state shown in FIG. 10 against the spring force of the return spring 516, and the fuel injection port 510a opens. For this reason, when the solenoid 511 is excited in a state where the pressure of the fuel is applied from the pressure accumulating chamber 203 to the hollow portion of the passage forming member 509, the fuel is discharged as shown in FIG.
As shown by a solid arrow therein, the fuel passage 508c of the valve stem 508, the nozzle case 506, and the fuel injection nozzle 5 pass from the circular hole of the adjusting screw 513 through the circular hole of the upper magnet 507a.
The fuel is injected from the fuel injection port 510a into the combustion chamber 57 along a fuel supply passage formed by a gap between the valve shaft 10 and the valve rod 508. When the excitation of the solenoid 511 is released, the armature 515 is moved downward together with the valve rod 508 by the return spring 516 in FIG.
08a closes the fuel injection port 510a and the fuel supply is cut off.

FIGS. 12 and 13 show another embodiment of the fuel injection type engine. FIG. 12 is a sectional view of a cylinder top of the fuel injection type engine, and FIG. 13 is a plan view of a cylinder head of the fuel injection type engine. . The accumulator chamber 203 of the fuel injection type engine of this embodiment has a first
-Aluminum pipe 20 extending from the third cylinder 10 to 12
3a is cast and formed.
a is cast in the cylinder head 51 near the first to third injectors 360 to 362. Accumulator 203
Are pressurized fuel supply paths 204 to 206 and the high pressure fuel pump 2
01, the pressurized fuel supply path 204 to
The length of the fuel injection pipe 206 is extremely shorter than that of the above-described embodiment, and the fuel pipe between the pressurized fuel and the first to third injectors 360 to 362 is shortened. As a result, the responsiveness is further improved.

[0061]

As described above, according to the first aspect of the present invention, since the pressurized fuel supply passage is formed in the cylinder head, the connecting structure between each injector and the high-pressure fuel pump is simple and inexpensive. is there. In addition, a pressurized fuel supply passage is formed in the cylinder head, and the pressurized fuel supply passage and each injector communicate with each other in the cylinder head, so that the high-pressure fuel is heated by the cylinder head and injected into the cylinder accordingly. It is possible to improve the vaporization after the gas is burned, to bring out the performance sufficiently, or to sufficiently reduce the unburned gas component. An accumulator is disposed between the pressurized fuel supply path and the high-pressure fuel pump, and the pressure in the accumulator is increased by the fuel pressure actuator when the engine is started and reduced when the engine is stopped. Also, by returning the fuel from the accumulator to the upper part of the maze of the sub-tank with a partition plate provided in the fuel tank under the control of the high-pressure regulator, and supplying the fuel into the fuel tank through the opening at the lower part of the maze, the return fuel can be defoamed. It is possible to eliminate the irregular existence of bubbles in the upstream part of the high-pressure fuel pump, for example, bubbles generated when returning from the high-pressure side and bubbles generated by vapor in the low-pressure part,
Stable fuel supply becomes possible, and stable engine performance is obtained.

According to the second aspect of the present invention, the high-pressure regulator is disposed in the accumulator, and is opened when the pressure of the accumulator becomes equal to or higher than a predetermined value, and the fuel is returned to the upper part of the maze of the sub-tank with the partition plate. Can be adjusted with a simple structure using a single high-pressure regulator.

[0063]

According to the third aspect of the present invention, since the pressure accumulating chamber is formed in the cylinder head, the connection structure between the pressure accumulating chamber and the pressurized fuel supply passage is simple, and the high pressure fuel is more effectively heated by the cylinder head. Accordingly, the vaporization after being injected into the cylinder can be improved, and the performance can be sufficiently obtained, or the unburned gas component can be sufficiently reduced.

[Brief description of the drawings]

FIG. 1 is a diagram of a fuel injection system.

FIG. 2 is a sectional view of a cylinder top of a fuel injection engine.

FIG. 3 is a plan view of a cylinder head.

FIG. 4 is a plan view showing a state of being mounted on an automobile.

FIG. 5 is a cross-sectional view of the fuel tank.

6 is a sectional view taken along the line VI-VI in FIG.

FIG. 7 is a sectional view taken along the line VII-VII in FIG. 6;

FIG. 8 is a diagram of a fuel injection system including an engine starting device.

FIG. 9 is a control timing chart of the engine.

FIG. 10 is a sectional view of an injector.

FIG. 11 is an enlarged sectional view of a distal end portion of the injector.

FIG. 12 is a sectional view of a cylinder top portion of another embodiment of the fuel injection engine.

FIG. 13 is a plan view of a cylinder head of another embodiment of the fuel injection engine.

[Explanation of symbols]

 7 Fuel injection type engine 10-12 Cylinder 51 Cylinder head 201 High-pressure fuel pump 204-206 First-third pressurized fuel supply path 360-362 First-third injector

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-62-131942 (JP, A) JP-A-5-321787 (JP, A) JP-A-7-109963 (JP, A) JP-A 8- 21340 (JP, A) Japanese Utility Model 5-1854 (JP, U) Japanese Utility Model Application No. Sho 63-10264 (JP, U) “Nihon Denso Public Technical Report”, No. 91, Nihon Denso Co., Ltd., July 15, 1993, reference number 91-085 (58) Fields investigated (Int. Cl. ⁷ , DB name) F02M 55/02 310 F02M 55/02 350 F02M 47/00 F02M 61/14 F02M 37/00

Claims (3)

(57) [Claims] 1. A fuel injection system comprising: supplying a fuel in a fuel tank by a low-pressure pump; pressurizing the fuel by a high-pressure fuel pump; and injecting the fuel into each cylinder from injectors respectively arranged in a plurality of cylinder heads. In the engine, a pressurized fuel supply path is formed in the cylinder head, the pressurized fuel supply path and each injector communicate with each other in the cylinder head, and the pressurized fuel supply path and the high-pressure fuel pump are connected. An accumulator is provided between the pressurized fuel supply path and the high-pressure fuel pump, and a fuel pressure actuator for increasing or decreasing the pressure in the accumulator is provided. The fuel actuator has a pressurized chamber whose volume is variable by a piston. The pressurizing chamber and the accumulator are communicated with each other through a pressure communication passage. The accumulator is pressurized when the engine is started, and depressurized when the engine is stopped. A sub-tank with a partition plate having a maze formed by a partition plate is provided in the fuel tank, and the fuel is returned from the accumulator to the upper opening of the maze of the sub-tank with the partition plate by the control of the high-pressure regulator, and the fuel is supplied from the lower opening of the maze to A fuel injection engine configured to be supplied into a tank. 2. The fuel cell system according to claim 1, wherein the high-pressure regulator is arranged in the pressure accumulating chamber, and is opened when the pressure in the pressure accumulating chamber becomes a predetermined value or more, and returns fuel to an upper part of a maze of the sub-tank with the partition plate. A fuel injection engine as described. 3. The fuel injection engine according to claim 1, wherein the accumulator is formed in the cylinder head.