JPS6128051Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a fuel supply device for a diesel engine or the like.

Conventionally, fuel supply systems for this type of engine mainly inject fuel into the combustion chamber of the engine using a main injection nozzle, and also sub-inject fuel into the intake passage using a sub-injection nozzle to increase the amount of fuel. , the fuel and air are premixed and the fuel is burned at an appropriate rate to reduce the amount of exhaust gas.
In order to reduce NOx and noise, an injection control valve is interposed between the sub-injection nozzle and the fuel injection pump, and this injection control valve is used to adjust the generator output and intake pressure according to the engine output. It is known that the presence or absence of sub-injection of fuel is controlled by controlling the
No. 61642).

However, in addition to the fuel injection pump and the main and auxiliary injection nozzles, the conventional fuel supply system described above requires a separate complicated and expensive injection control valve, and also requires a control system for the injection control valve. However, the disadvantage is that the overall configuration is complicated and expensive.

Therefore, the purpose of this invention is to create a simple and inexpensive configuration that does not require an injection control valve, and to control the main injection into the combustion chamber.
It is an object of the present invention to provide a novel fuel supply device for an engine that can perform sub-injection into an intake passage and can freely control the sub-injection according to the operating state of the engine.

Therefore, this invention supplies fuel into the combustion chamber from a main injection nozzle disposed in the combustion chamber of the engine, and also supplies auxiliary fuel to the intake passage from a sub-injection nozzle disposed in the intake passage. In the fuel supply system for the engine, the main fuel distribution passage communicates with the main injection nozzle; the auxiliary fuel distribution passage communicates with the auxiliary injection nozzle; and the same number of main injection cam ridges and auxiliary injection cam ridges as the number of engine cylinders. and a plunger mechanism that contacts the cam surface of the cam member and reciprocates within the cylinder to forcefully feed fuel to the discharge passage; upstream of the pump device; A metering device having a metering mechanism disposed to measure fuel to be supplied according to the operating state of the engine, and a pump located upstream of the metering mechanism to supply metered fuel into the cylinder; The cam member includes a distribution device that communicates the discharge passage with the main fuel distribution passage when in contact with the injection cam crest, and communicates the discharge passage with the auxiliary fuel distribution passage when in contact with the auxiliary injection cam crest. By configuring the lift amount of the sub-injection cam mount to be smaller than the lift amount of the main injection cam mount, sub-injection to the intake passage and main injection to the combustion chamber can be easily and inexpensively performed, reducing NOx, It is characterized by being able to reduce noise, and by controlling the amount of protrusion of the plunger using a metering device according to the operating state of the engine, the presence or absence of sub-injection can be controlled.

Hereinafter, this invention will be explained in detail with reference to the illustrated embodiments.

In FIG. 1, 1 is a fuel injection pump consisting of a pump device 2 and a distribution device 3, and 5 is a fuel tank 6.
a fuel supply pump that sucks fuel from the inside through a suction pipe 7 and supplies it to the filter 10 through a pipe 8;
Reference numeral 11 indicates that the filtered fuel in the filter 10 is connected to the pipe 1.
2 is a transfer pump consisting of a vane pump that sucks in air and pumps it under pressure; 13 is a pipe line 14 that communicates the suction side and the discharge side of the transfer pump 11;
A relief valve 15 is installed in the transfer pump 1 to control the discharge pressure of the transfer pump 1 to a certain value or above. This is a metering valve as a metering device that supplies fuel to the fuel injection pump 1.

The metering valve 15 has lands 21 and 2.
A piston 25 having an annular groove 23 between the piston 25 and the piston 25 is slidably fitted into a housing 26, and a conduit 16 is inserted into a chamber 27 formed on one end surface of the piston 25.
The fuel discharged from the transfer pump 11 is guided through the piston 2, and the fuel in the chamber 27 is guided through the piston 2.
5 into the annular groove 23 through a passage 28 formed in the housing 26 , and the axial movement of the piston 25 causes the land 22 to connect the annular groove 23 and the outlet port 29 formed in the housing 26 and communicating with the conduit 17 . The opening degree of the diaphragm 30 between the two is controlled. Therefore, the metering valve 15 measures fuel according to the opening degree of the throttle 30 and supplies it to the fuel injection pump 1.

Further, a coil spring 33 is compressed between the other end surface of the piston 25 and one end of a control lever 32 whose substantially middle portion is rotatably supported by a shaft 31, so that the piston 25 acts on the one end surface. By opposing the fuel pressure and the spring force of the spring 33,
It is made to be displaced in the axial direction.

The control lever 32 is designed to operate in conjunction with an accelerator pedal (not shown). For example, when the engine is under high load and at high speed, the control lever 32 is rotated in the direction of the arrow X in FIG. is displaced to the right in FIG. 1 via the coil spring 25 to increase the opening degree of the throttle 30 and increase the amount of metered fuel supplied to the fuel injection pump 1 in accordance with the operating state of the engine. There is.

On the other hand, as shown in FIGS. 1 and 2, the fuel injection pump 1 is rotatably fitted into the housing 35, and rotates about 1/2 rotation in response to the rotation of the engine crankshaft (not shown). A part of the drive shaft 36, which rotates at a constant rate, is connected to a large-diameter disk-shaped cylinder block 3.
7, and the cylinder block 37 is provided with a radial through hole passing through the center, so that they are mutually connected.
Cylinders 38, 38 having a phase of 180 degrees are formed. The cylinders 38, 38 each include:
Plungers 41, 41 having roll holders 40, 40 supporting rollers 39, 39 at their outer ends are slidably fitted therein.

Cam rings 42 as cam members are arranged at regular intervals on the outer periphery of the cylinder block 37, and the cam rings 42 are connected to the housing 35.
It is fixed at As shown in FIG. 2, the cam ring 42 has four main injection cam ridges 45a on its inner peripheral surface, the same number as the number of engine cylinders (for example, four cylinders), and four sub-injection cam ridges 45a. The main injection cam ridges 45a and the sub-injection cam ridges 45b are alternately arranged. The lift amount of the main injection cam ridge 45a is as follows:
As shown in FIG. 3, the sub-injection cam ridge 45
The dimensions are set larger than the lift amount of b.

A chamber 46 between the inner end surfaces of the plungers 41, 41
In this case, a passage 47 located at the axis of the drive shaft 36 is communicated with the passage 47, and as shown in FIG.
8,488,48 are connected.

The suction passages 48, 48... are connected to the housing 35
The fuel metered by the metering valve 15 is communicated with the inlet port 49 provided in the pipe line 17 every 1/4 rotation of the drive shaft 36, and the fuel metered by the metering valve 15 is supplied to the pipe line 17.
The fuel is introduced into the chamber 46 through the inlet 49, the suction passage 48, and the passage 47, and the fuel pressure causes the plunger 41 and the roller 39 to move into the main injection cam ridge 45a.
It is made to protrude outward along the .

Further, at the end of the fuel passage 47, first and fifth
As shown in the figure, one radial discharge passage 50
As the drive shaft 36 rotates, the distal end opening of the discharge passage 50 is sequentially communicated with each distribution passage 52a, 52b, 52a, 52b, . I try to let them do it. The distribution passage 52a,
The phases of the opening positions of 52b, . . . are 45 degrees apart, and the plungers 41, 41 are pushed into the cylinder 3 by the cam ridges 45a, 45b, . At this time, the discharge passage 50 and the distribution passages 52a, 52b, 52a, . . . communicate with each other. The distribution passage 52a is for main fuel, and the distribution passage 52b is for auxiliary fuel.The main and auxiliary distribution passages 52a, 52b open alternately on the inner peripheral surface of the housing 35.

The main fuel distribution passage 52a is shown in FIG.
Only cylinders are shown. ), the main injection nozzle 61 provided in the cylinder head 60 of the engine E is connected to inject fuel into the fuel chamber 62, while each sub-fuel distribution passage 52b is connected to the intake passage 63 of each cylinder. It is connected to the provided sub-injection nozzle 65. The sub-injection nozzle 65 is arranged to inject fuel toward the upstream side of the intake passage 63, and utilizes the dynamic pressure of intake air to promote atomization and atomization of the injected fuel.

As shown in FIG. 7, the sub-injection nozzle 65 is
A concave ceramic member 72 having a protrusion 72a at the bottom is covered and fixed to the lower part of the body 71 with a hole 73 in the lower part of the case 73.
The protruding portion 72a is made to protrude from a.

Internal space 7 of the concave ceramic member 72
4, the fuel is guided through a passage 75 provided in the body 71, and is injected from small diameter nozzle holes 76, 76 provided in the protrusion 72a.

Since the nozzle holes 76, 76 are formed of the ceramic member 72, the ceramic material shrinks during firing, making it possible to configure the nozzle hole diameter to be extremely small. Atomization and atomization of the fuel can be promoted even without the use of a sieve), the reachability of the fuel to the combustion chamber 62 is good, and the mixing and combustibility of the fuel are good.

A needle 77 is attached to the body 71 so as to be movable back and forth, and fuel is injected by lifting the needle 77 using fuel pressure.

In FIG. 1, reference numeral 81 indicates a return line for returning internally leaked fuel from the fuel injection pump 1 to the filter 10, and reference numeral 82 indicates a line for returning fuel and air overflowing from the filter 10 to the tank 10.
The plunger mechanism in this invention is composed of a roller 39, a roller holder 40, and a plunger 41 in this embodiment. The pump device 2 also includes a housing 3 in which an inlet 49 is formed.
5, and a part is made into a large-diameter disk shape, and a cylinder 3 is placed inside.
8, a rotating drive shaft 36 forming a suction passage 48, a passage 47 communicating with the chamber 46 of the cylinder 38, the suction passage 48, and the discharge passage 50, and the roller 3.
9. It is composed of a plunger mechanism consisting of a roller holder 40 and a plunger 41, and a cam ring 42 which is a cam member. The metering device is a control lever 3 that is linked to the accelerator pedal.
2. A metering mechanism consisting of a coil spring 33 and a metering valve 15, a transfer pump 11, a relief valve 13, and a pipe line 12,1
Consists of 4,16. Further, the distribution device 3 rotates in synchronization with the engine and is composed of a drive shaft 36 in which a discharge passage 50 is formed in the radial direction, and a housing 35 in which distribution passages 52a and 52b communicating with the main and sub-injection nozzles are opened. .

The engine fuel supply system configured as described above operates as follows.

Now, the engine is under high load and high speed operation, and the control lever 32 is being rotated in the direction of arrow X beyond the state shown in FIG.
through the aperture 3 to the predetermined position in Fig. 1.
It is assumed that the opening degree of 0 is controlled to a predetermined value.

Then, in the chamber 46 of the fuel injection pump 1,
In the suction stroke where the suction passage 48 and the inlet 49 communicate, the amount of fuel measured by the metering valve 15 is supplied, and according to the metered fuel,
The roller 39 attached to the plunger 41 projects to line F in FIG. Then, as the drive shaft 36 rotates, the tip of the suction passage 48 is closed by the inner peripheral surface of the housing 35, and the plunger 41 and roller 39 are guided by the sub-injection cam ridge 45b and pushed into the cylinder 38, Fuel is pressurized in the chamber 46 and the passageway 4
7, discharge passage 50, and auxiliary fuel distribution passage 52
b, the fuel is force-fed to the sub-injection nozzle 65, and then sub-injected into the intake passage 63.

At this time, the fuel is injected from the sub-injection nozzle 65 toward the upstream side and from the small-diameter nozzle hole 76 formed in the ceramic member 72, so that it is atomized and atomized to improve its miscibility with air. and the reachability to the combustion chamber 62 is improved.

Furthermore, when the drive shaft 36 rotates,
The plunger 41 is further pushed into the chamber 46 by the adjacent main injection cam ridge 45a via the roller 39, and pumps the fuel. At this time, since the discharge passage 50 communicates with the main fuel distribution passage 52a, the fuel is supplied to the main injection nozzle 61 through the main fuel distribution passage 52a, and the fuel is supplied to the combustion chamber 6.
2. Squirt inside.

In this way, under high load and high rotation, sub-injection of fuel into the intake passage 63 and main injection into the combustion chamber 62 are performed, so that fuel and air are premixed and combustion is slowed down. This can reduce NOx and noise in exhaust gas.

Next, it is assumed that the control lever 32 is rotated in the direction opposite to the direction of arrow X to perform low-load operation.

Then, the orifice 30 of the metering valve 15
Since the opening degree of the fuel injection pump 1 becomes smaller, less fuel is introduced into the chamber 46 during the suction stroke where the inlet 49 of the fuel injection pump 1 and the suction passage 48 communicate with each other.
The tip of the roller 39 that protrudes through the plunger 41 due to the fuel is located on the line P in FIG. 3.

Therefore, even if the drive shaft 36 rotates at this time, the roller 39 will not move toward the sub-injection cam ridge 45b.
, the plunger 41 is not pushed into the cylinder 38, and fuel is not forced into the auxiliary fuel distribution passage 52b and the auxiliary injection nozzle 65. On the other hand, the main injection cam mountain 4
Since the roller 39 contacts 5a, the plunger 41 is pushed into the cylinder 38. Therefore, at this time, the fuel in the chamber 46 is force-fed to the main injection nozzle 61 via the passage 47, the discharge passage 50, and the main fuel distribution passage 52a, and is injected into the combustion chamber 62. In this manner, in the case of a partial load indicated by line P in FIG. 3, only the main injection into the combustion chamber 62 is performed, so that deterioration of thermal efficiency due to premature ignition timing under light loads can be prevented.

Note that lines I and D in FIG. 3 indicate the position of the protruding tip of the roller 39 when the engine is idling. The operation at this time is substantially the same as that at partial load.

In this way, this fuel supply device supplies the main injection to the combustion chamber 62 and the intake passage 6 with one fuel injection pump.
In addition to performing sub-injection to 3, check whether there is sub-injection or not.
The metering valve 15 controls fuel metering according to the operating state of the engine, and the fuel injected from the sub-injection nozzle 65 is atomized by the intake operation and the small-diameter nozzle 76 of the ceramic member 72. It is.

In the above embodiment, the main fuel is injected into the combustion chamber, but in an engine equipped with a sub-combustion chamber such as a swirl chamber, the main fuel may be injected into the sub-combustion chamber. Further, the fuel supply pump 5 is connected to the tank 6
It may be removed depending on the height relationship between the pump device 2 and the pipe length between them.

As is clear from the above explanation, this invention alternately forms the same number of main injection cam ridges and sub-injection cam ridges as the number of engine cylinders on the cam member, and increases the lift amount of the auxiliary injection cam ridges. In the cylinder of the pump device, the dimensions are smaller than the lift amount of the main injection cam mount, and the plunger mechanism is brought into contact with the surface of the cam member and reciprocated in the cylinder to forcefully feed fuel. , the metering device measures and supplies fuel, causes the plunger mechanism to protrude from the cylinder according to the metered amount of fuel, and pushes the plunger mechanism into the cylinder by a cam member to force-feed the fuel; Since the fuel pumped from the device is distributed to the main and sub-injection nozzles by the distribution device, sub-injection to the intake passage and main injection to the combustion chamber can be easily performed using one fuel injection pump device.
It is inexpensive, reduces NOx and noise, and
The presence or absence of sub-injection can be controlled by controlling the amount of protrusion of the plunger using a metering device depending on the operating state of the engine.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of the main parts of an embodiment of this invention.
Figure 2 is a sectional view taken along the - line in Figure 1, Figure 3 is a developed view of the cam ring, Figure 4 is a sectional view taken along the - line in Figure 1, Figure 5 is a sectional view taken along the - line in Figure 1, and Figure 6 is a sectional view taken along the - line in Figure 1. The figure is a cross-sectional view of the engine and the intake passage, and FIG. 7 is a cross-sectional view of the sub-injection nozzle. 1... Fuel injection pump, 15... Metering valve, 38... Cylinder, 41... Plunger,
42... Cam member, 45a... Main injection cam mountain,
45b...Cam mountain for sub-injection, 61...Main injection nozzle, 65...Sub-injection nozzle.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) Fuel is supplied into the combustion chamber from the main injection nozzle disposed in the combustion chamber of the engine, and auxiliary fuel is supplied to the intake passage from the sub-injection nozzle disposed in the intake passage. In the fuel supply system for the engine, the main fuel distribution passage communicates with the main injection nozzle;
a auxiliary fuel distribution passage communicating with the auxiliary injection nozzle; a cam member in which cam ridges for main injection and cam ridges for auxiliary injection, the same number as the number of engine cylinders, are arranged alternately;
A pump device having a plunger mechanism that contacts the cam surface of the cam member and reciprocates within the cylinder to forcefully feed fuel to the discharge passage; a pump device that is disposed upstream of the pump device and supplies fuel according to the operating state of the engine. A metering device having a metering mechanism for metering fuel, and a pump located upstream of the metering mechanism and supplying metered fuel into the cylinder; when the plunger mechanism is in contact with the main injection cam ridge, the main fuel is A distribution device is provided that communicates the discharge passage with the auxiliary fuel distribution passage when in contact with the auxiliary fuel distribution passage, and the lift amount of the auxiliary injection cam crest of the cam member is adjusted to the main injection cam crest. A fuel supply device for an engine, characterized in that the lift amount is smaller than that of a cam mount. (2) The fuel supply device for an engine according to claim 1, wherein the injection port of the sub-injection nozzle is made of a ceramic member.