JPS608123Y2 - Injection amount correction device for distribution type fuel injection pump for internal combustion engine - Google Patents

Description

[Detailed description of the invention] This invention is a distribution type fuel injection pump for an internal combustion engine that uses a rotating and reciprocating plunger to pressurize and distribute fuel oil to each cylinder of a multi-cylinder internal combustion engine. The present invention relates to an outlet volume distribution type fuel injection pump for an internal combustion engine that controls the fuel discharge amount of a plunger and adjusts the fuel injection amount by displacing a freely fitted control sleeve.

In general, in this type of injection pump, as shown in FIG. 4 is slidably attached.

The start lever 5 is rotatably attached to a pin 6 on a collector lever (not shown) that is rotatably fixed to the pump body 4, and has a pin 8 at one end that engages with a recess in the control sleeve 7. is locked, and a start spring 9 is attached to the other end so that the start lever 5 always comes into contact with the free end of the governor shaft 1.

A plunger 10 is slidably fitted into the control sleeve 7, and is provided coaxially with the camshaft 2, rotates and reciprocates, and pressurizes and distributes fuel oil to each cylinder of the engine via a delivery valve. ing.

The camshaft 2 is provided with an I, ZG-type feed pump (not shown), and is pressurized to approximately 1.5 ko/a1 supplied from the primary pump 18 shown in FIG. The fuel is further pressurized and supplied into the pump body 4.

The supplied fuel pressure within the pump main body 4 varies in proportion to the rotational speed, for example reaching a maximum of 8 to 9/art.

A tension lever 11 is rotatably attached to the pin 6 to which the start lever 5 is attached, and this lever 11 acts as a support member for the start spring 9, and when the governor shaft 1 moves, the tension lever 11 is rotated.
It is designed to rotate together with the pin 6 as a fulcrum.

The start spring 9 acts to rotate the start lever 5 counterclockwise about the pin 6 so as to displace the control sleeve 7 in the fuel increasing direction (to the right in the figure) in order to increase the amount of fuel at the time of starting.

A governor spring 13 is attached to the opposite side (other end) of the tension lever 11 via an idle spring 12, and the governor spring 13 is connected to an accelerator pedal or the like of the vehicle via a control lever (not shown). When starting and at the highest rotational position, the tension lever 11 is moved to the full load stopper 4 of the pump body 4.
It is designed to be pulled until it hits point a.

Therefore, the speed regulating action is achieved by the tension lever rotatably attached to the pump body resisting the arbitrarily set governor spring in response to the governor shaft moving as the flyweight expands as the engine speed increases. The rotation is performed by displacing the control sleeve.

However, the amount of fuel injected tends to gradually increase as the rotation speed increases even if the position of the control sleeve remains constant, whereas the amount of fuel required by the engine decreases as the engine's air intake efficiency increases as the engine speed increases. Therefore, the amount of injection tends to decrease little by little, and it is therefore necessary to reduce the injection amount as the rotational speed increases.

In contrast, in supercharged engines and the like, it is necessary to increase the amount of injection as the rotational speed increases.

For this reason, in the past, for example, the tension lever was provided with a spring device activated by the displacement of the governor shaft, and the fuel injection amount characteristics for the maximum load were determined at a rotation speed at which no regulating action was performed, that is, at which the tension lever did not begin to pull the governor spring. The stroke of the governor shaft is used for control, but in this case most of the stroke of the governor shaft is used for this control, resulting in insufficient control of the tension lever.

Moreover, when changing the injection quantity characteristics, the injection pump must be disassembled, which is inconvenient.

The purpose of this invention is to eliminate such inconvenience, and
It is an object of the present invention to provide a fuel injection amount correction device that corrects injection amount characteristics with respect to maximum load to match engine requirements related to engine speed.

Next, this invention will be explained with reference to embodiments shown in FIGS. 2 to 5.

Referring to FIG. 2, a piston 14 corresponding to the aforementioned full load stopper 4a is inserted into the pump body 4, which is pressurized and supplied by a feed pump (not shown) against a spring 15. A capsule 16 is screwed in, slidably housed under fuel pressure.

This piston 14 has a control end projecting into the interior of the pump body from a hole 16a in the capsule, which is connected to the cylindrical shaft 14.
a and a conical portion 14b that becomes thicker toward the tip.

In addition, there is a through hole 1 inside the spring 15 of the capsule 16.
6b, the discharge side pressure of the primary pump 18 which pumps up the fuel oil in the fuel tank 17 and supplies it to the suction side of the feed pump built into the injection pump main body 4 at a substantially constant low pressure is partially branched and acts. It is made to be.

As a result, the pressure fluctuations that the piston 14 receives from the fuel cut pressure inside the pump body 4, for example, caused by the control sleeve 7 during the injection path, can be compensated for by applying the discharge side pressure of the primary pump 18 to the chamber of the spring 15 of the piston 14. vibration of the piston 14 can be prevented.

Here, when the collector lever (not shown) is set to the maximum rotational position to maximize the tension of the governor spring 13 and the tension lever 11 is pulled all at once so that its end comes into contact with the control end of the piston 14, as described above, As the engine speed increases, the fuel pressure inside the pump body increases, so the piston 14 rises, and the shape of its control end allows the tension lever 11 to rotate clockwise about the pin 6. .

This allows the control sleeve 7 on the plunger 10 to
is displaced in the direction of fuel reduction, and the fuel injection amount can be reduced.

In this state, the vertical axis is the fuel injection amount Q, and the horizontal axis is the engine speed N.
To explain the injection amount characteristic diagram shown in FIG. , the start spring 9 overcomes the resistance of the flyweight 3 to open, and the governor shaft 1 moves to start, the lever 5 rotates, and the control sleeve 7
The figure shows a state in which the fuel is displaced in the fuel decreasing direction.

In the range of C% d, the injection amount is not controlled because the fuel pressure is insufficient and the piston 14 does not displace. However, as the rotation speed increases further from point d, the piston 14 rises as described above. In the range d - e, the conical part 14b
The injection amount is reduced to match the intake air amount depending on the shape of the shaft portion 14a in the range e to f.

Thereafter, when the rotational speed increases from point f and the centrifugal force of the flyweight 3 overcomes the tension of the governor spring 13, the tension lever 11 rotates together with the start lever 5 about the pin 6, and the general speed regulating action is resumed. It is done.

Note that the dotted line indicates the characteristics obtained with an injection pump not equipped with an injection amount correction device.

FIG. 4 shows another embodiment of this invention, in which the piston 14' has a cylindrical shaft portion 14'a and a conical portion 14'b tapering toward the tip, so that the piston 14' is shown in FIG. as shown
In the ranges d/~e' and e'~f', contrary to what is shown in FIG. 2, the injection amount can be increased as the rotational speed increases.

In order to change the injection quantity characteristics apart from the above-described embodiments, the housing can be removed from the pump body, and the shape of the control end of the piston can be changed or the spring constant of the spring inside the housing can be changed.

Furthermore, as shown in FIG. 4, if a roller 19 is provided at the end of the tension lever 11 that contacts the pistons 14, 14', the sliding resistance will be reduced and the injection amount can be controlled more accurately. can.

Note that if so-called wax pellets are used as the pressing mechanism for the piston 14, it is possible to correct the injection amount according to the temperature of the fuel oil.

In this way, according to this invention, it is not only possible to obtain the injection amount characteristics for the maximum load according to the various engine requirements without disassembling the injection pump body, but also because the stroke of the governor shaft is not used, the tension lever can be adjusted. The control range for speed regulation can be made sufficiently large, and it is possible to prevent the danger that would arise due to failure to obtain a no-injection state in the control.

[Brief explanation of drawings]

FIG. 1 is a partial vertical cross-sectional view showing a conventional distribution type fuel injection pump, FIG. 2 is a partial cross-sectional explanatory view showing the main part of an embodiment of this invention, and FIG. FIG. 4 is a fuel injection amount characteristic diagram showing the injection amount characteristics obtained in the example, FIG. 4 is a partial sectional view showing a piston and a tension lever according to another example of this invention, and FIG. FIG. 3 is a fuel injection amount characteristic diagram according to an embodiment of the present invention. 1: Governor spring, 3: Fly weight, 4: Pump body, 5 Nistart lever 7 = Control sleeve, 10 Nib lunge gear, 11: Tension lever, 13
: Governor spring, 14.14': Piston, 15 spring, 16: Capsule.

Claims (4)

[Scope of utility model registration request] (1) A rotating and reciprocating plunger distributes fuel oil under pressure to each cylinder of a multi-cylinder internal combustion engine, and a governor shaft, which is displaced by the opening and closing of a flyweight related to the engine speed, is installed on a pin of a collector lever. The start lever and tension lever are rotated against the governor spring to displace the control sleeve in which the plunger is slidably fitted, thereby controlling the fuel discharge amount of the plunger and adjusting the fuel injection amount. In an outlet volume type distribution type fuel injection pump for an internal combustion engine, a capsule is provided in the pump body to which the fuel pressure discharged from a feed pump built in the pump body acts, and a capsule is placed in the capsule to which the fuel pressure is applied. A piston having a control end that is displaced accordingly and projects outside the capsule is slidably housed via a spring, and the side of the piston where the spring is housed is connected to the suction of the feed pump in the fuel injection pump. An injection amount correction device characterized in that the pressure on the discharge side of a primary pump that supplies fuel to the piston is applied, and when the piston is displaced, the rotation of the tension lever can be controlled by the control end of the piston. (2) The device according to claim 1, wherein the control end portion comprises a cylindrical shaft portion and a conical portion tapering toward the tip. (3) The device according to claim 1, wherein the control end portion comprises a cylindrical shaft portion and a conical portion that tapers toward the tip. (4) The device according to claim 2 or 3, wherein a roller is provided at the end of the tension lever that comes into contact with the control end of the piston.