JPS59155569A - Oil feeding rate control device for fuel injection pump - Google Patents

Abstract

PURPOSE:To permit to change and control the oil feeding rate freely in accordance with the operating condition of an engine by a method wherein a plunger is formed by a plurality of plungers of inner and outer concentrical plungers to control the initial position of compression and change an effective diameter related to compression stroke. CONSTITUTION:The sleeve 43 of the plunger is brought to right end to push the outer plunger 22 against an end wall to feed oil through only the small diametral inner plunger 21, whereby, a small injection rate is obtained, slow combustion is effected and noise as well as the discharging amount of NOx are reduced. When the sleeve 43 is controlled to the intermediate position, the flange 71 of the plunger 21 is abutted against the sleeve 43, the plunger 22 is also controlled in accordance therewith and a large injection rate is obtained by the small injection rate of the plunger 21 at the initial period and the composite oil feeding amount of both plungers 21, 22 at the last period of the control. Next, when the sleeve 43 is controlled to a position abutting against the flange 71 of the plunger 21, the integral stroke of the plungers 21, 22 is effected from the beginning of the oil feeding to effect the composite oil feeding of both plungers to obtain the large injection rate and whereby the high output operation of the engine may be effected.

Description

TECHNICAL FIELD The present invention relates to an oil feed rate control device for a fuel injection pump in a fuel injection internal combustion engine.

<Background Art> A conventional example of a fuel injection pump for a fuel injection internal combustion engine, such as a tasel engine, is shown in FIG. 1 (see Technical Explanation 1 "Diesel Engine", published by Nissan Motor Co., Ltd., January 1977).

This is a distribution type fuel injection pump that suctions and pressure-feeds fuel by the reciprocating motion of the plunger, and distributes the pumped fuel to the fuel injection valves arranged for each cylinder by rotation, and rotates in synchronization with the engine rotation. A drive shaft 1 and plungers 3 and 5, which can freely slide and rotate reciprocally within the barrel 2, are connected to each other so as to be freely movable in the axial direction, and the plunger 3 is rotationally driven.
A cam disk 4 formed at the base end of the plunger 30 is driven by a cam roller 5 to cause the granger 3 to reciprocate.

As the granger 3 reciprocates, the fuel in the pump housing 6 is sucked into the plunger chamber 8 through the suction passage 7, and the sucked fuel is transferred to the fuel passage 14 formed in the plunger 3 and the distribution boat 15. A delivery pulp 10 is opened to send fuel to a fuel injection valve (not shown) through an oil feed passage 9 provided for each cylinder.

The plunger 3 has a cut-off boat 11 that reefs the fuel in the plunger chamber 8 into the pump housing 6.
A control sleeve 12 for controlling opening and closing of the cutoff bolt 11 is disposed around the outer circumference of the plunger 3 so as to be freely slidable in the axial direction. The control sleeve 1
2 closes the cut-off boat 11, the fuel in the plunger chamber 8 is pumped by the reciprocating movement of the plunger 3, but the cut-off boat 11 comes off the end surface of the control sleeve 12 and the bonder housing 6 When the plunger chamber 8 is communicated with the plunger chamber 8, the fuel pressure in the plunger chamber 8 decreases and fuel supply is stopped.

Therefore, in the fuel injection, the granger 3 moves to the right in the figure to compress the fuel in the plunger chamber 8, opens the delivery valve 10 and pumps the fuel, and then the cut-off boat 11 passes from the end surface of the control sleeve 12. This continues until the fuel pressure in the plunger chamber 8 decreases and fuel injection ends.

The position of the control sleeve 12 is controlled by the cabana 13 in accordance with the amount of depression of an accelerator pedal (not shown) and the engine rotational speed.

Further, the reciprocating timing of the plunger 3 is controlled by changing the phase of the cam roller 5 around its axis.

In the type of fuel injection pump that sucks fuel into the plunger chamber 8 and pumps it from there by reciprocating the plunger in this way, the cutoff boat 11 is always closed by the control sleeve 12. Conventionally, the oil feeding rate at the initial stage of oil feeding is generally determined by the pump specifications. That is, the amount of oil sent from the plunger chamber 8 is the effective stroke of the plunger 3 until the cut-off boat 11 is released by the control sleeve 12 and the cross-sectional area of the plunger 3, and the amount of oil sent from the plunger chamber 8 is determined by the amount of oil sent with respect to the engine crank angle. That is, the oil feed rate is the product of the plunger stroke and the cross-sectional area of the plunger chamber 8 relative to the crank angle.

Here, since the stroke of the plunger relative to the crank angle is always constant regardless of the rotational speed of the engine, the oil feed rate must also be constant.

For this reason, for example, if the initial oil feeding rate during engine idle link is set to the required oil feeding rate by reducing the diameter of one langeer, the injection period will be changed to secure the injection needle in the engine high speed rotation and high load region. In order to avoid this, if the initial oil feed rate during engine idling is set high, combustion noise will increase and NOx emissions will increase, resulting in a historic problem. This poses a dilemma in that combustion deteriorates and fuel efficiency worsens.

Purpose of the present invention In view of the above-mentioned disadvantages of the conventional device, the present invention provides a simple structure in which the effective diameter related to the compression stroke of the plunger is changed to freely control the ejection rate in accordance with the engine operating state. purpose.

<Summary of the Invention> To this end, in the present invention, the plunger is composed of a plurality of plunger parts that are overlapped concentrically inside and outside and are free to move in the axial direction, and these plunger parts are reciprocated by a driving means, and the initial position of the compression stroke of the plunger part is is determined by the positioning means according to the engine operating state, and the timing at which oil feeding starts for each plunger section relative to the engine rotation angle is controlled, and the oil feeding rate of the pump as a whole is variably controlled by combining the oil feeding rates of each of these plunger sections. Provides an oil feed rate control device.

<Example> Embodiments of the present invention will be described below based on the drawings.

FIG. 2 shows the main part of the present invention, and is an improved version of the structure around the granger 3 and granger chamber 8 of the conventional example shown in FIG. Since the other parts are the same as those of the conventional example except for the control sleeve 12 and governor 13 parts shown in FIG. 1, the explanation thereof will be omitted.

<Structure> In Fig. 2, there is a rond-shaped inner plunger 21, which corresponds to the conventional plunger 3 that sucks in and pumps fuel, and a cylindrical outer plunger 21 that overlaps concentrically with the inner plunger 21 in the outer circumferential direction of the inner plunger 21. The plunger 22 is formed by a plurality of granja parts, and both granjar parts 21, 22 -
For example, a key 23 provided on a part of the outer periphery of one inner plunger 21 and a key groove 24 provided on the inner periphery of the outer plunger 22 extending in the axial direction are configured to be able to freely slide in the axial direction, so that they can mutually slide in the axial direction. Constructed to rotate freely and together. Similarly to conventional plungers, the inner plunger 21 is connected to a drive shaft (Fig. 1) through a joint, rotates in synchronization with engine rotation, and reciprocates in the axial direction, and the outer plunger 22 follows this. Rotate.

A fuel passage 25 is provided in the inner lunge 21 to communicate the plunger chamber 8 with a distribution boat 26 that is open in a part of its outer peripheral surface, and a communication port 27 corresponding to the distribution port 26 is provided in the outer lunge 22. The page is opened radially through the pages.

The communication port 27 is formed to be axially long so as to constantly communicate with the dispensing port 26 even when the two plungers 21, 22 move relative to each other in the axial direction.

A solenoid valve 30 is installed in the suction passage 7 to open and close it, and a detection signal from an engine operating state detection device consisting of an engine rotation sensor 31 or an engine load sensor 32 is sent to the controller 3.
3, the pre-stored value is read and calculated, and then the solenoid valve 30 is opened and closed in accordance with the output signal. During the pumping stroke of the plunger 21, 22, the solenoid valve 30
If the valve is open, the fuel in the plunger chamber 8 is discharged into the pump housing 6 through the suction passage 7, so there is no fuel flow that is forced into each injection valve when the delivery pulp 10 is opened. Fuel is not injected. On the other hand, if the solenoid valve 30 is closed, the fuel pressure in the plunger chamber 8 will increase, and the distribution boat 26 will be connected to one of the oil supply passages 9 via the communication boat 27.
When the cylinders communicate with each other, fuel is supplied to the corresponding injection valve and fuel is injected into each cylinder.

Therefore, the electromagnetic valve 30 can arbitrarily control the start timing and end timing of fuel supply, that is, injection.

Next, the positioning means for determining the initial position of the compression stroke of each plunger 21, 22 and the driving means will be described.

The inner plunger 21 is connected to the cam disc 4 as described above.
and cam roller 5 to compress the air by the cam mechanism (c)
- An initial position is determined, and the cam mechanism and the drive shaft 1 rotate and reciprocate in the axial direction. Therefore, in the inner plunger 21, the cam mechanism is a positioning means for determining the initial position of the compression stroke, and the cam mechanism, the drive shaft 1, etc. are the driving means.

The positioning means 4o of the outer plunger 22 is
The hydraulic servo mechanism 41 is controlled according to the operating state of the engine, and an actuator 42 is operated for positioning by the hydraulic servo mechanism 41.

That is, a sleeve 43 is fitted onto the outer periphery of the proximal end of the inner granger 210 so that it can slide in the axial direction, and a support shaft 46 of a lever 45 is slidably engaged at one end in a circumferential groove 44 of the sleeve 43. The sleeve 43 is positioned by the rotational position. Since fuel pressure acts on the end face of the plunger chamber 811111 of the outer plunger 22, the outer plunger 22 moves to the left due to the pressure and comes into contact with the sleeve 43.
The initial compression stroke position of No. 2 is determined.

The other end of the lever 45 is inserted into a locking groove 48 formed in a piston rod 47 of the tandem piston type actuator 42. The locking groove 48 is provided to prevent "play" in the axial direction, and a spring 49 housed in the locking groove 48 causes the other end of the lever 45 to lean against the end wall of the locking groove 48 on the plunger chamber 8 side, thereby causing the sleeve to close. 430 is restricted from moving toward the opposite side of the plunger chamber, and the lever 45 is free to swing due to the movement of the sleeve 43 toward the plunger chamber 8 side.

Chambers 52 on both left and right sides of the piston 51 of the actuator 42.
Fuel metered by the hydraulic servo mechanism 41 is introduced into the piston 51.53. J) Positioning is done.

The hydraulic servo mechanism 41 has a supply port 61 connected to a fuel pump (not shown) connected to either chamber 52 or 53 of the actuator 42.

A spool valve 64 has three positions, two positions in which the other chamber 53 or 52 is communicated with a return port 62, 63 connected to a fuel tank (not shown), and a position in which communication with each passage is cut off. This is done by controlling the energization and demagnetization of solenoids 65 and 66 provided at both ends of the spool pulp.

Such duty control is performed by the engine rotation sensor 3.
The sleeve 43 is controlled by a controller 33 so as to be in a predetermined optimal position in response to a detection signal from an engine operating state detection device comprising an engine load sensor 1, an engine load sensor 32, and the like.

A drive device for driving the outer plunger 22 in the compression direction is constituted by a flange 71 provided at the base end of the inner plunger 210. During the compression stroke of the inner plunger 21, the flange 71 moves the outer plunger 22 toward the plunger chamber 8 side through the sleeve 43. Press. In addition, both the inner granger 21 and the outer granger 22 receive the fuel pressure introduced into the plunger chamber 8, and the anti-plunger plan 8
Be pushed to the side. However, at this time, apart from the inner plunger 21 which receives a return force from the return spring ring (FIG. 1 17) as in the past, when the outer plunger 22 comes into contact with the right end wall of the plunger chamber 8, it returns to the left in the figure. Since there is a possibility that no force will be generated, a groove 72 is provided on the top surface of the outer grunge 22 to ensure a pressure receiving surface at this time.

<Operation> Therefore, according to the above configuration, the rotational driving force of the drive shaft 1 that is synchronized with the engine rotation rotationally drives the inner plunger 21 and also rotationally drives the outer plunger 22 via the key 23.

During this rotation, the inner grunger 21 lifts to the right in the figure every time the face cam of the cam disk 4 at its base end rides on the cam roller 5, and compresses the fuel in the plunger chamber 8 and connects it to the distribution port 26. Fuel is pumped to the oil feed passage 9 for each cylinder via a communication boat 27 that is always connected to the cylinder. Oil supply amount Q1 of the inner plunger 21 at this time
is the product of the effective compression stroke of the inner granger 21 and its cross-sectional area when the solenoid valve 30 is closed.

On the other hand, the oil feed ftQ2 of the outer plunger 22 is as follows.

It is the product of the effective compression stroke of the outer plunger 22 and its cross-sectional area after the collar 71 comes into contact with the sleeve 43 when the solenoid valve 30 is closed and the inner plunger 21 is on the compression stroke. This effective compression stroke is delayed by the position of the sleeve 43, that is, the initial position of the compression stroke of the outer plunger 22 (
It becomes smaller as it moves to the right position in the figure.

Therefore, the oil feed rate of the oil feed amount Q1 and Q2 of each plunger with respect to the engine crank angle is such that the later the initial position of the compression stroke of the outer plunger 22 is, the smaller the oil feed rate by the inner grunger 21 can be initially obtained. Possible 1. For example, in the engine idle position shown in FIG. 3 (5), the sleeve 43 is brought to the right end position and the outer plunger 22 is pressed against the end wall of the granger chamber 8, and oil is supplied only by the small-diameter inner plunger 21. By doing this, a small 1M ejection rate is obtained as shown in FIG. 3(a), and by controlling the injection timing of the solenoid valve 30, the injection time is lengthened to perform slow combustion and reduce combustion noise.1. Reduce NOx emissions.

During partial load, the third
As shown in Figure (B), by controlling the sleeve 43 to be at an appropriate position between its left and right end positions, the outer plunger 22 is at its initial compression stroke position, that is, when the collar 71 of the inner plunger 21 is in contact with the sleeve 43. The outer plunger position is also controlled accordingly, and as shown in FIG. 3(b), at the beginning of oil feeding, the inner plunger 21 provides a small injection rate, and in the later stage of oil feeding, the combined injection rate of both plungers 21 and 22 is applied. A large injection rate can be obtained based on the amount of oil. This type of injection rate control reduces the amount of fuel that causes ignition delay at the beginning of injection, such as pilot injection or prior injection, and allows a large injection amount to be obtained after or just before ignition, achieving slow combustion and reducing combustion noise. , NOx emissions are improved.

For example, when you want to improve the combustion state and obtain high output, at the full load stage, as shown in Fig. 3 (q), the sleeve 43 is placed at the left end position, that is, when it is not lifted or does not enter the effective compression stroke, the inner plunger 210 contacts the collar 71. From the beginning of the oil supply, the inner plunger 21 and the outer plunger 22 are stroked integrally to perform a synthetic oil supply as shown in FIG. 3(C).
Obtain large injection rate.

Such arbitrary sleeve position control is performed using the solenoid 65,
This is done by ON/OFF duty control of 66. That is, when the left solenoid 65 is energized and energized, the spool valve 64 moves to the left and the actuator 4, which is the supply boat 61, moves to the left.
2 and the left chamber 52 to the return port 62, the piston 51 moves to the left and the lever 45
The sleeve 4 is rotated clockwise around its support shaft 46.
3 to the right in the figure, and vice versa when the right solenoid 66 is energized and energized. Then, the spool valve 64 stops at its neutral position (the position where the springs disposed at both ends of the spool 64 are balanced, and at this time both solenoids 6
5.66 are both sake mash], then the painting room is 52.5
3 and each of the boats 61 to 63 is cut off, so the left and right movement of the snowboard 43 is locked. Therefore, by controlling the selection time of these three positions of the spool valve 64 in a vibrational manner through duty control in which the solenoids 65 and 66 are repeatedly turned on and off, the sleeve 4
3 can be specified at any position. After the position of the sleeve 43 has been controlled, if the spool nozzle 64 is set to the neutral position and the sleeve position is locked at that position, high pressure is applied within the plunger chamber 8 and the outer plunger 22 is moved to the sleeve 43 at the position. The sleeve 43 and spool 64 can be prevented from moving to the left even if they come into contact with the sleeve 43 and the spool 64 during the compression stroke.
3 is pressed by the collar 71 and moves to the right, the end of <-45 moves in the locking groove 48 against the elastic force of the spring 490, so that the sleeve 43 moves to the right. It's not an obstacle.

In the above embodiment, since the large fuel pressure in the plunger chamber 8 acts on the sleeve 43, the sleeve 43 is controlled by a hydraulic servo mechanism located at the position of the sleeve 43. It is also possible to adopt a suitable means for bringing a face cam into contact with a face cam having a lift characteristic depending on the state (also, by independently providing means for determining the initial compression position and driving means for the inner and outer plungers, The plunger may be operated arbitrarily to perform oil feed rate control with a high degree of freedom and excellent accuracy.

Furthermore, although this embodiment has shown an example of a distribution type fuel injection pump, the present invention can suck and pump fuel using other reciprocating plungers such as a row type injection bong or a unit injector that combines a pump and an injection valve. It can be applied to all pumps designed for

Historically, in the present embodiment, the plunger portion is constructed with double inner and outer plunger portions, but it goes without saying that the plunger portion may be constructed with three or more layers of concentric plunger portions in keeping with the spirit of the present invention.

In place of the concave groove 72 provided for the return of the outer plunger in the embodiment, a sleeve 83 is fixedly attached directly to the outer plunger 22 as shown in FIG. By providing a spring to act on the outer plunger, it may be possible to return the outer plunger to the left in the drawing.

As described above, according to the present invention, the plunger is constituted by a plurality of concentric plunger parts on the inside and outside, and the initial compression position of these plunger parts is controlled, so that the cross-sectional area of the oil feed by the plunger can be arbitrarily controlled. It is possible to obtain the optimum oil feed rate characteristics.

[Brief explanation of drawings]

Fig. 1 is a longitudinal sectional view of a conventional device of the present invention, Fig. 2 is a sectional view of essential parts showing an embodiment of the present invention, Fig. 3 is an explanatory diagram of the same operation, and (5) is an engine idle link. (B) is at partial load + (C) is at full load operation, (a)
~(C) are injection rate characteristic diagrams corresponding to the above, respectively. FIG. 4 is a sectional view of a main part showing another embodiment of the present invention. 1... Drive shaft 4... Cam disc 5
...T cam roller 6...Pump housing γ...
・Suction passage 8...Plunger chamber 9...Oil supply passage 21...Inner plunger 22...
Outer plunger 40... positioning means 41...
... Hydraulic servo mechanism 42 ... Actuator 43
．． 83... Sleeve 71... Boxwood patent applicant
Nissan Motor Co., Ltd. Representative Patent Attorney Sasa & Fujio

Claims (1)

[Claims] In a fuel injection pump equipped with a plunger that reciprocates to suck in and pump fuel, the plunger is composed of a plurality of plunger parts that are overlapped concentrically inside and outside and can move freely in the axial direction, and the compression stroke of these plunger parts is An oil feed rate control device for a fuel injection pump, comprising: a positioning means for determining an initial position according to an engine operating state; and a driving means for reciprocating the plunger portion.