JPS6067764A - Fuel injection pump - Google Patents

Abstract

PURPOSE:To reduce the weight of a movable part of a fuel injection pump so as to require only less power for driving said part by trisecting a barrel, into which a plunger is inserted, into the upper, middle and lower members and using the middle member as a movable barrel for regulating fuel injection timing. CONSTITUTION:A barrel into which a plunger 5 is inserted is trisected into the upper, middle and lower members 2-4. The upper member is used as a stationary barrel in which fuel is urged to be sent by the combinational operation with the plunger 5. The middle member 3 is used as an injection timing regulating movable barrel having therein both an intake port 22 and a spill port 24 which are movable in the axial direction of the plunger 5 for communication with the reed part 25 of the plunger 5. In addition, the lower member 4 is used as a stationary barrel for sealing between a fuel oil chamber 21 and a plunger spring chamber 7. The part having direct relation with the injection timing is separated and serves as the movable barrel 3, whereby reducing the weight of a movable part and requiring less power for driving said part.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fuel injection pump that allows injection timing to be changed arbitrarily.

Fuel injection pumps used in diesel engines, etc.
In many cases, the injection timing is fixed to be optimal at the maximum practical output, but during low load or low speed operation, the injection timing deviates from the optimal conditions, resulting in deterioration of fuel efficiency, exhaust gas concentration, increase in noise, and poor starting. Such problems may occur. In order to deal with this, there are some models that allow the injection timing to be changed. It is known that the positions of the suction boat and spill boat can be changed relative to the plunger using buttons.

This type of fuel injection pump pumps fuel by applying high pressure to the fuel, so the sliding parts of the barrel and plunger are finished with extremely high fitting precision, and the barrel and bomb must be removed in seven steps. Since the seal between the two barrels must be well sealed, the frictional resistance of the seal is large, and a large driving force is generally required to move the barrel. In both cases, the entire barrel is moved, and therefore, in addition to the frictional force, the claws of the entire barrel are also added, and the force required for driving becomes even greater. For this reason, for example, when barrel driving force is obtained using centrifugal force accompanying engine rotation, it is possible to compensate for operational response delays due to frictional force during rack drive and inertia of the rack drive device including the link mechanism, and to properly position the barrel. In order to control this, the drive mechanism becomes quite large. In the case of such a mechanical drive system, it is possible to solve the problem by increasing the size to a degree that does not impede practical use, but if you try to apply an electronic control system to perform more appropriate control, For example, the attraction force or repulsion force of a solenoid is used as the driving force, and in order to obtain the necessary driving force, the electric capacity B of the actuator becomes excessive, making it difficult to put it into practical use. A dot is produced.

The present invention has been made with the aim of providing a fuel injection pump that is easy to apply an electronic control system to, paying attention to the problems of the conventional example. Divided into three members, the upper member is a fixed barrel that is combined with a plunger to form a plunger chamber for pumping fuel, and the middle member is a lead s of the plunger.
A movable barrel for adjusting the injection timing forms a suction boat and a spill boat that can be moved in the axial direction of the plunger in accordance with K, and the lower member is a fixed barrel that seals between the fuel oil chamber and the granger spring chamber. It is a feature. That is, in the present invention, since the part directly related to the injection timing is separated and made into a movable barrel, the mass of the movable part is significantly reduced, and the frictional resistance during movement is also reduced. The required barrel driving force can be reduced.

Therefore, it is possible to downsize the drive actuator, and it becomes easy to adopt an electronic control method. Since the upper and lower barrels are still fixed, sealing is also easier.

Hereinafter, the invention will be specifically explained based on one embodiment shown in the drawings.

In the figure, (1) is the crankshaft of the pump, (2) is the upper fixed barrel, (3) is the movable barrel, (4) is the lower fixed barrel, and (5) is the plunger. Upper fixed barrel (
2) and the lower fixed barrel F41D is fixed in the housing flll, and the movable barrel (3) is attached to each fixed barrel, +21 +
4) and is axially movably inserted into the Hakling+11, and the plunger (5) is axially movably inserted into each of these fixed barrels (2), (4) and movable barrel (3). It is placed in a closet so that it can be moved. (6) is a lubricating oil holding groove provided in the plunger (5).

+71 Fi plunger spring chamber formed at the bottom of the housing (1), (8) is the plunger spring, (9) is the tappet, the tappet (9) is attached to the lower end of the plunger (6), and the plunger spring (8) is compressed between the upper spring receiver (10) on the housing +11 side and the lower spring receiver (Il) on the plunger (5) side, and the plunger (5) is pushed upward by a cam (not shown). and is pushed back downward by plunger spring (8)K. In addition, the plunger spring chamber (7) K is
A control sleeve θ is provided with a control rank 03) and a control pinion (14) that meshes with the control rack 0. The control sleeve 05) has a groove end at the lower end engaged with a collar θ provided on the granger (6), and the control sleeve 05) is used to move the control rack 0 in a direction perpendicular to the plane of the drawing. ) rotates, and the plunger (5) rotates via the collar 07).幀 is rank (I sliding direction guide pin that reduces the rotation stopper of the sleeve, 0
9) is a C-shaped lip to prevent the tappet from falling off.

62I) is a busy hacking f to surround the movable barrel (3).
A fuel oil chamber (2D) is formed on the inner surface of the l+, and a fuel oil chamber (2D
241 is a spill port formed in the movable barrel (3); 241 is a spill port formed in the movable barrel (3);
C). The suction boat (incorporated) is placed in communication with the lead portion □□□ when the plunger (5) is located below, and the spill boat (incorporated) is provided in communication with the lead portion □□□ when the plunger (5) is located above. That is, fuel is fed to the fuel oil chamber Qυ from the fuel filler port (not shown), and when the granger (5) is near the bottom dead center, the fuel is sent to the suction boat (3), the lead part (sha), and the relief hole □□ □ is supplied to the plunger chamber (2η) formed by the plunger (5) and the upper fixed barrel (2), and the plunger (5
) moves to the ascending process, and the reed part (goods) and suction boat (3
) When the communication with the plunger (
6) further rises and the lead part (material) communicates with the spill boat (material), the pumping stops. A plunger (5) corresponding to the period during which this pressure feeding is performed, that is, the fuel injection amount.
The effective stroke is performed by rotating the plunger (5) using the control rack and changing the position fEi of the tilted top picture (25a) of the lead part 4 with respect to the spill boat K. Delivery pulp C311 is provided on the top of the crank f1).
It is urged downward by the delivery spring, and is normally closed by being pressed against the pulp guide (i131), but when the plunger (5) rises and is forced to feed, it opens against the spring (32) and the pulp holder Fuel is injected through a delivery pipe (not shown) connected to.

Member 0 is a spill protector installed in response to the spill boat.

(3 forces are the barrel drive rack, (38) the barrel drive pinion that meshes with the barrel drive, the country is the annular barrel holder, uO) is the disaster spring, the pinion (goods) and the barrel holder) are , are arranged overlappingly between the stepped portion aa> formed on the upper fixed barrel (2) and the upper end surface G3a) of the movable barrel (3), and contact between the pinion (c) and the rail presser 03G). As shown in FIG.
4 I am composed. In addition, this surface cam mechanism (4I)
It utilizes the wedge action of one side of the claw, and can be replaced with other mechanisms such as a bolt or screw. The return spring (kn) is connected to the step (3b) of the movable barrel (3) and the lower edge of the fuel oil chamber @υ (
21a), and urges the movable barrel (3) in the direction.

The barrel drive rack m71 is designed to move in the direction perpendicular to the plane of the paper in FIG. Due to the wedge action of the inclined surfaces (38a) and (39a) K, the distance G between the pinion 8) and the barrel presser (39) changes, and the movable barrel (3) moves in the axial direction. Therefore, the upper part 1 (22a) of the suction boat (2) and the spill boat are connected to the lead part (b) K of the plunger (5).
By changing the position and the timing of the start and stop of pressure feeding, it is possible to change the timing of fuel injection.
3) are respectively formed with axial grooves (39b) and (3c), and the guide bottle is wrapped around the guide bottle to prevent rotation, and the barrel presser 0 (end) is provided with a through hole (44I). 1) K
It communicates.

2'7) is an O-ring that seals the gap between the lower fixed barrel (4) and the crankshaft (1), and +4FQ is an oil supply path provided in the lower fixed barrel (4). The oil supply passage (one is open in the annular groove (9) formed on the inner peripheral surface of the lower fixed barrel (4), and the other end is in the annular groove (c) 0) provided in the crankshaft (fl)K. It opens in the opening, and the check valve light υ
It is connected to a high-pressure supply source of lubricating oil (not shown) via piping. That is, when the plunger (5) reciprocates up and down, lubricating oil is supplied to the circumferential surface of the plunger (5),
The lubricating oil holding groove (6) of the plunger (5) is an annular groove, 4
9), lubricating oil is also supplied here, and the sliding surfaces between the plunger (5) and the lower fixed barrel (4) are forcibly lubricated, and at the same time, the oil film of lubricating oil is tilted to the fuel oil chamber. A seal is made between the cutting and the plunger spring chamber (7). This K, together with the action of the O-ring (47), prevents fuel from leaking into the plunger spring chamber (7).

Note that the upper half of the plunger (5) is lubricated with fuel oil.

As mentioned above, control rack 0→ld ftA
The barrel drive rack 7) controls the amount of material to be injected and the timing of the injection, and the position is adjusted by a mechanical drive mechanism or an electric actuator. Figure 3 shows an example of this, in which the barrel drive rack (37) is controlled by a stepping motor (5).In other words, the stepping motor (a) Output shaft (5 (2)
), the tip of the output shaft (66) and rack C! are brought into contact with one end of the rack force. The mounting portion η of the rack 07 is screwed into the mounting hole of the crank (1+) so that the rack 07 is located on the same axis as the rack 07. ) is provided with a compression spring held by a spring retainer) which urges rank 7) in the direction of the stepping motor □□□. The stepping motor operates according to the output signal from the control circuit of a microcomputer, etc.
When rotates, the output shaft or Q moves forward and backward in the axial direction due to the action of the screw joint -, and the rank (37), which is biased by the compression spring hook, follows the output shaft - and moves in the axial direction. death,
The barrel drive pinion rotates to move the movable barrel (3) as described above, thereby controlling the injection timing. (Incorporated) is the output shaft (561 rotation stopper and guide pin).

This embodiment has the above-mentioned structure and function), and has a divided barrel and a movable barrel (3) for adjusting the injection timing.
The surface cam mechanism has a small mass and utilizes the slope ←1)
Since the movable barrel (3) is pushed by the movable barrel (3), the driving force of the rack (31) for moving the movable barrel (3) may be small, and the rack is moved by a small-capacity stepping motor or an electric actuator such as a near solenoid. Reference η
This makes it easy to adopt electronic control using a microcomputer or the like. Particularly in the case of large engines, it is common to have a single fuel injection pump for each cylinder, and if you try to control the injection timing mechanically, the main body mechanisms such as connecting links are large and heavy. However, in the case of electric actuators, it is necessary to mechanically connect each pump, so it is necessary to provide an actuator for each pump. Since it is possible to control all cylinders all at once, electronic control can be easily adopted, which is a particularly great advantage in the case of large engines with a large number of cylinders.

As is clear from the above embodiments, in the present invention, the barrel is divided into three parts, and the portions forming the intermediate suction boat and spill boat are used as movable barrels for adjusting the injection timing.
The mass of the moving parts is reduced, reducing the required driving force, and responsiveness is also improved, making it possible to drive with a relatively small and small-capacity electric actuator, making it easier to adopt electronic control methods. . Also, since the upper and lower barrels are both fixed, sealing is easy, making it possible to obtain a highly efficient fuel injection pump with less fuel leakage.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of one embodiment of the present invention, FIG. 2 is a front view of the same surface cam mechanism, and FIG. 3 is a sectional view taken along the line A--A in FIG. 1. +11...Ha cylinder, (2)...Upper fixed/-Cylinder, (3)...Movable barrel, (4)...Lower fixed barrel, (5)...Plunger, (7)...・Plunger spring chamber, υ... fuel oil chamber, (2'4... suction boat, (2) 荀... spill boat, (to)...
Lead part, shiη...plunger chamber. Patent applicant Yanmar Diesel Co., Ltd. Agent Patent attorney Tsutsu 1) Minoru

Claims (1)

[Claims] fx) The barrel into which the plunger is pushed is divided into three members, upper, middle and lower, and the upper member is a fixed barrel that is combined with the plunger to form a granger chamber for pumping fuel,
The middle member is a movable barrel for adjusting the injection timing that forms a suction boat and a spill boat that can be moved in the axial direction of the plunger in correspondence with the lead part of the plunger, and the lower member is used to seal the opening between the fuel oil chamber and the plunger spring chamber. A fuel injection pump characterized by having a fixed barrel.