JPS61265354A - Fuel injection device - Google Patents

Abstract

PURPOSE:To make an injection characteristic accurately settable, by varying the relative position of a plunger and a control sleeve with an actuator. CONSTITUTION:When injection timing and the specified value of an injection quantity both vary according to an engine running state or the like, actuators 20 and 21 are operated, varying the relative position of a plunger 6 and a control sleeve 11, and an injection characteristic is accurately set. In this case, two fuel injection pump parts 3a and 3b are formed with a stepped plunger 6, and the control sleeve 11 is installed in one side pump part 3b side by side, whereby the injection timing is regulated. Therefore, when the pump part 3b is utilized for pilot injection and fuel injection out of the pump part 3b is made so as to be done before an injection start from the pump part 3a, timing for the pilot injection can be set to an optimum value with the control 11 utilized.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a fuel injection device used in a diesel engine or the like, and more particularly to a unit inductor that integrates a fuel injection pump and a fuel injection nozzle.

(Prior Art) Generally, a unit injector includes a fuel injection pump and a fuel injection nozzle using a common body assembly.
A pressurized chamber of the pump is connected to the nozzle via a passage within the body assembly. Therefore, there is no need to provide a long high-pressure pipe between the pump and the nozzle, and there is an advantage that there is little need for a so-called advance device, and at the same time, the fuel injection rate can be easily increased.

Recently, in order to improve exhaust performance and fuel efficiency, electronic control devices using solenoid valves have been used to control the unit injector's injection timing and injection rate (the amount of fuel injected per unit movement of the plunger 17). Some systems have also adopted methods that set the injection timing and injection rate to optimal values under all operating conditions.

(Problem to be solved by the invention) However, in the conventional structure, the injection amount and injection timing are
Since the settings and controls are made every time (for each injection operation) by generating control oil pressure and changing the speed of the solenoid valve, there is a problem that the durability of the solenoid valve is low, and there is also a problem that the durability of the solenoid valve is low. Due to changes in oil pressure, etc.
There is also the problem of poor performance due to the difference in A. Another problem is that pilot injection is difficult because the response speed of the solenoid valve is slow. Furthermore, in a multi-cylinder engine, there is also a problem that the injection timing and injection amount are inconsistent among the cylinders.

(Means for Solving the Problems) In order to solve the above problems, the present invention provides a fuel pressurizing plunger 1 which has a small diameter part and a large diameter part inside the body assembly!
a first fuel injection pump is formed by having a small diameter portion of the plunger facing a first pressurizing chamber inside the body assembly, and a large diameter portion of the plunger facing a second pressurizing chamber inside the body assembly. to form a second fuel injection pump, an injection nozzle connected to both pressurizing chambers is formed at the tip of the body assembly, a control sleeve is fitted to the outer periphery of the small diameter part or the large diameter part, and the plunger and the sleeve is provided with a control passage communicating with the pressurizing chamber, the control passage is filled in response to the reciprocating movement of the plunger, and the closing period and closing timing are changed by relative movement of the sleeve and the plunger. The present invention is characterized in that a control mechanism is connected to the sleeve and the plunger to relatively move them in the axial direction and the circumferential direction.

(Example) In FIG. 1, a body assembly 1 of a unit injector is fitted and fixed in a hole of a cylinder head 2 in a vertical position, for example. The upper half of the body assembly 1 forms fuel injection pump parts 3a, 3b, and the lower part forms a fuel injection nozzle 4.

A barrel 5 of the pump 3 is fitted and fixed inside the body assembly 1, and a plunger 6 is slidably fitted into the inner peripheral surface of the barrel 5. The upper end of the plunger 6 is connected via a tappet 9 to a cam mechanism (not shown). The cam mechanism causes the plunger 6 to reciprocate, thereby sucking in and pressurizing fuel in the pressurizing chambers 7a and 7b inside the body assembly 1, as will be described later. Also body assembly 1
A passage 8 is provided that connects the pressurizing chambers 7a, 7b and the nozzle 4, and the fuel pressurized in the pressurizing chambers 7a, 7b is sent from the passage 8 to the nozzle 4.

The plunge +76 integrally includes a large diameter portion 6b and a small diameter portion 6a protruding from its tip (lower end). The pressurizing chamber 7a (first pressurizing chamber) is formed below the small diameter portion 6a, and the circular tip surface of the small diameter portion 6a faces the pressurizing chamber 7a. That is, the small diameter portion 6a, the pressurizing chamber 7a, and the body assembly portion around them form the first fuel injection pump portion 3a, and the fuel in the pressurizing chamber 7a is pressurized in the direction of the tip of the small diameter portion 6a. It has become.

The other pressurizing chamber 7b (second pressurizing chamber) is formed below the large diameter portion 6b and around the upper portion of the small diameter portion 6a.
The annular tip surface of b faces the pressurizing chamber 7b. That is, the large diameter portion 6b, the pressurizing chamber 7b, and the body assembly portion around them form the second fuel injection pump portion 3b,
The annular 8 tip end surface of the large diameter portion 6b pressurizes the fuel in the pressurizing chamber 7b.

The barrel 5 has a cutout portion forming a chamber 10 in the vertically intermediate portion, and an annular control sleeve 11 is disposed in the chamber 10. The control sleeve 11 is a plunge V
It is slidably fitted to the outer periphery of the large diameter portion 6b, and is movable relative to the plunger 6 in its axial direction (vertical direction) and circumferential direction. A control passage 12 connecting the pressurizing chamber 7b and the chamber 10 is provided in the plunger 6 and the control sleeve 11, as will be described later. Further, the barrel 5 is provided with a passage 14 connected to the pressurizing chamber 7a.

A supply passage 15 is connected to these chambers 10 and passages 14 . The supply passage 15 is provided inside the cylinder head 2 and the body assembly 1, and fuel sent to the supply passage 15 from a feed pump (not shown) is supplied to each chamber 1.
0 and pressurized chambers 7b and 7a via the control passage 12 and passage 14.
It is designed to be supplied to

Specifically, the control passage 12 includes a plunger large diameter Wils
A passage hole 16 extending from the outer peripheral surface of the plunger 6b to the pressurizing chamber 7b through the inside thereof, an inclined groove 17 provided on the outer peripheral surface of the plunger large diameter portion 6b, and a passage hole 18 penetrating the control sleeve 11 in the radial direction. It consists of While the plunger 6 makes one reciprocating motion, the inclined groove 17 temporarily communicates with the passage hole 18. In this manner, the control passage 12 is opened once depending on the position of the plunger 6 during reciprocating movement, and when it is opened, fuel is sucked into the pressurizing chamber 7b, and when it is closed, fuel is pressurized in the pressurizing chamber 7b.

The control passage 12 is configured so that its characteristics change depending on the position of the control sleeve 11, and its closed period is determined by the control sleeve 11 relative to the plunger 6.
The opening/closing timing changes depending on the relative circumferential position of the control sleeve 11 relative to the plunger 6.
varies depending on the relative axial position of the - The closing period is a factor that determines the pressurizing operation time in the pressurizing chambers 7a and 7b, that is, the fuel injection amount, and the opening/closing timing is a factor that determines the pressurizing timing in the pressurizing chamber 7b, that is, the fuel injection timing. It is. Therefore, by changing the circumferential position of the control sleeve 11, the pump part 3
The fuel injection amount at point b can be adjusted, and the fuel injection timing can be adjusted by changing the axial position.

An inclined groove 13 is also provided on the outer peripheral surface of the plunger small diameter portion 6a. This inclined groove 13 temporarily communicates with the passage 14 while the plunger 6 performs one reciprocating movement, and when the communication is made, fuel is sucked into the pressurizing chamber 7a, and when it is shut off, the pressurizing chamber 7a
The fuel is pressurized at point a. Also, the inclined groove 13 for the passage 14
The closing period of the control sleeve 711 varies depending on the circumferential position of the control sleeve 711 relative to the plunger 6. Therefore, by changing the relative circumferential position of the plunger 6 and the barrel 5, the amount of fuel injected by the pump portion 3a can be adjusted.

In order to adjust the injection characteristics as described above, an actuator 20 (control mechanism) for circumferential movement and an actuator 21 (control mechanism) for axial movement are connected to the plunger 6 and control sleeve 11, respectively. Mechanism 22.2
They are connected via 3. An actuator 20 (linear solenoid) and an actuator 21 (step motor) are respectively assembled to the body assembly 1 on both sides of the upper part of the body assembly 1, and both of them are in operation 0.
b protrudes downward. Further, a load sensor 19 is provided at the upper end of the actuator 20. Load sensor 19
and other sensors (not shown) are connected to a control device (microcomputer, etc., not shown), and according to signals from the control device, the actuator 20.21 moves the actuating rod 24.25. It has become.

Said connection I! ! MI! Reference numeral 22 includes a rack at the bottom of the operating rod 24, a pinion 26 that meshes with the rack, a shaft 27 with the pinion 26 fixed to one end, and the like.

The shaft 27 extends at right angles to the plunger 6 and is provided with a pin 29 at an eccentric position at its other end. The pin 29 is provided on a part of a flange-like lever at the tip of the shaft 27, and is fitted into an axial groove on the outer periphery of the sleeve 46. The sleeve 46 is a member located around the upper part of the plunger 6, and is provided with an axial notch 48 at the upper end.
is provided with a radially outward protrusion 49 that fits into the notch 48 in a manner that prevents relative rotation.

According to the above configuration, by changing the vertical position of the actuating rod 24 by the actuator 20, the shaft 27 is rotated via the pinion 26, and the pin 29 rotates the plunger 6 via the sleeve 46. As a result, the control sleeve 11 (passage hole 18) and the barrel 5 (passage 14)
, the relative circumferential position of the plunger 6 changes, and the fuel injection rate of both pump parts 3a and 3b changes.

The bamboo connection mechanism 23 also includes a rack at the bottom of the operating rod 25, a pinion 31 that meshes with the rack, a shaft 32 with the pinion 31 fixed to one end, and the like. Six shafts 32 extend perpendicularly to the plunger 6 and are provided with a pin 34 at an eccentric position at the other end. The pin 34 is provided on a portion of the lever at the tip of the shaft 32, and is fitted into a circumferential groove 35 on the outer periphery of the control sleeve 11. Therefore, by changing the vertical position of the operating rod 25 by the actuator 21, the shaft 32 is aligned via the pinion 31, and the bin 34
moves the control sleeve 11 up and down to change the fuel injection timing at the pump section 3b.

An adjusting plate 40 of the disproportionality mechanism 39 is attached to the outer surface of the body assembly 1 below the coupling mechanism 22 . Although not clearly shown, the adjustment plate 40 is a generally fan-shaped or triangular plate, and is equipped with a rotating pin 41 at the top, and an arc-shaped groove centered around the pin 41 at the bottom. . The shaft portion of the screw 43 is inserted into the groove. The screw 43 is screwed into the screw hole of the body assembly 1 and fixes the adjustment plate 40 unrotatably.The pin 41 is rotatably fitted into the hole of the body assembly 1, and the pin 41 is rotatably fitted into the hole of the body assembly 1. A bin 45 is provided at an eccentric position. The pin 45 is fitted into an axial groove formed on the outer periphery of the sleeve 11 so as to be non-rotatable.

As is clear from the above configuration, by temporarily loosening the screw 43 and operating the adjusting plate 40 to rotate the pin 41, the pin 45 rotates the sleeve 11, which causes the plunger 176 and the control 1 call to rotate. By changing the relative circumferential position of the sleeve 11, the initial setting value of the fuel injection amount of the pump section 3b can be adjusted.

(Effects of the Invention) As explained above, according to the present invention, the actuator 20.21 connects the plunger 6 and the control sleeve 11.
The fuel injection timing and fuel injection amount are changed by changing the relative positions of the actuators 20 and 21, and the actuators 20 and 21 are actuated only when the desired values of the injection timing and the injection amount change depending on the engine operating condition or the like. to change the above relative position. Therefore, the durability of the actuators 20, 21 can be increased, and the injection characteristics can be set accurately.

Further, in the present invention, two fuel injection pump parts 3a and 3b are constructed using a stepped plunger 6, and a control sleeve 11 is attached to one pump part 3b so that the injection timing thereof can be adjusted. There is. Therefore, if the pump part 3b is used for pilot injection and the fuel injection from the pump part 3b is performed before the start of fuel injection from the pump part 3a, the control sleeve 11 can be used to optimize the timing of the pilot injection. Can be set to a value. Furthermore, even when fuel injection is performed from both pump parts 3a and 3b at the same time, the relative injection characteristics of both can be adjusted by the control sleeve 11, and the injection characteristics of the pump 3 as a whole (for example, the overall injection amount Furthermore, during idling operation, etc., operation can be performed with only auxiliary injection from the pump section 3b, thereby reducing knock noise.

Further, by providing the non-uniformity ratio mechanism 39 as shown in the figure, it is possible to prevent variations in injection characteristics between cylinders in a multi-cylinder engine.

(Another Embodiment) Either a beam solenoid or a step motor can be employed as the actuator 20.21.

A control sleeve 11 is attached to the first fuel injection pump section 3a.
It is also possible to provide

It is also possible to eliminate the actuators 20, 21 and the coupling mechanism 22 in FIG. 1 and adopt a structure as shown in FIG. 2.

In FIG. 2, a pinion 55 is attached to the outer periphery of the sleeve 46.
is formed, and a rack 56 is engaged with the pinion 55. The rack 56 is incorporated into the body assembly 1, and is connected to an operating portion of a mechanical governor (not shown) via a link mechanism. A rack 57 is also engaged with the pinion 31 of the shaft 32. This rack is also body assembly 1
It is incorporated in the 1! It is connected to an operation control mechanism such as a generator handle or a hydraulic type.

[Brief explanation of drawings]

FIG. 1 is a sectional view of an embodiment of the present invention, and FIG. 2 is a sectional view of another embodiment. 1...Body assembly, 3a...1st
Fuel injection pump, 3b...Second fuel injection pump, 4.
...Injection nozzle, 6...Plunger, 6a...Plunge V small diameter part, 6b...Bufunji TP large diameter part, 7a...
...First pressurization chamber, 7b...Second pressurization chamber, 11...Control sleeve, 12...Control passage, 20.21
...actuator (control mechanism)

Claims (1)

[Claims] A fuel pressurizing plunger having a small diameter part and a large diameter part is provided inside the body assembly, and the small diameter part of the plunger is opposed to a first pressurizing chamber inside the body assembly to form a first fuel injection pump, a large diameter portion of the plunger faces a second pressurizing chamber inside the body assembly to form a second fuel injection pump;
An injection nozzle connected to both of the pressurizing chambers is formed at the tip of the body assembly, a control sleeve is fitted around the outer periphery of the small diameter portion or the large diameter portion, and the plunger and the sleeve communicate with the pressurizing chamber. A control passage is provided, the control passage comprising:
It opens and closes in response to the reciprocating motion of the plunger, and the closing period and closing timing change depending on the relative movement of the sleeve and plunger, and the sleeve and plunger are arranged relative to each other in the axial and circumferential directions. A fuel injection device characterized in that a control mechanism for moving the fuel injection device is connected to the fuel injection device.