JPS6249458B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fuel injection timing adjustment device for internal combustion engines, particularly diesel engines.

With conventional fuel injection pumps for diesel engines, once a predetermined injection timing is set, it is impossible to make significant timing adjustments not only during operation but even when the engine is stopped. Therefore, as a means for adjusting the injection timing within a certain range during operation, a method is generally adopted in which a plunger in the injection pump is provided with an injection timing setting lead. However, with this method, only a certain amount of adjustment can be made depending on the load, that is, the fuel injection amount, and it is impossible to vary the injection timing depending on the type of fuel or various other operating conditions. In marine diesel engines in particular, where there are many variations in the type and quality of the fuel used, it is necessary to adjust the injection timing accordingly, but since there is no dedicated timer, it is not possible to change the timing set on the engine side. I couldn't do it.

In order to improve the above problems, a fuel injection pump with variable injection timing has been proposed in which the plunger has a double structure. However, this injection pump has a drawback in that when timing adjustment is performed, the fuel injection amount changes accordingly.

FIG. 1 shows an example of such a variable injection timing injection pump, in which a plunger barrel 2 having an overflow port 2a which also functions as a suction port and a timing port 2b is positioned within the pump body 1. A plunger 5, which is a combination of a main plunger member 3 and a sub-plunger member 4, is inserted into the plunger barrel 2.
The main plunger member 3 has an injection amount setting lead 6 attached to a head 6 which is rotatably and slidably fitted into the barrel 2.
a, and its lower end is rotatably attached to a tappet 7 driven by a camshaft (not shown), and is spring-loaded downward by a plunger spring 8. On the other hand, the sub-plunger member 4 having an injection timing setting lead 4a on its head is assembled between the lower end of the head 6 of the main plunger member 3 and the stepped portion 3a, and rotates and slides inside the plunger barrel 2. They are fitted freely. Therefore, when the main plunger member reciprocates under the action of the tappet 7 and the plunger spring 8, which are rotated by the camshaft, the sub plunger member 4 also slides within the barrel 2. An annular oil reservoir chamber 1a within the pump body 1 is always filled with fuel, and fuel is supplied into the plunger chamber through an overflow port 2a of the barrel 2. The fuel is pumped by the upper end of the head of the main plunger member 3 closing the overflow port 2a, and the injection timing setting lead 4a of the sub-plunger member 4 closing the timing port 2b.
is started by closing the main plunger member 3.
The process ends when the injection amount setting lead 6a communicates with the overflow port 2a.

The sub-plunger member 4 has a collar portion 4b at its lower end that engages with a notch 9a of a control sleeve 9, and the control sleeve 9 is fitted into the lower part of the plunger barrel 2 and passes through the pump body 1 in the lateral direction. It is engaged with timing rack 10. Therefore, by manually or automatically operating the timing rack 10, the secondary plunger member 4 is
As a result, the timing at which the injection timing setting lead 4a closes the timing port 2b, that is, the injection timing changes. The control sleeve 9 also has a notch 11a that engages with the collar 3b of the main plunger member 3.
A control sleeve 11 having a
This control sleeve 11 is engaged with a control rack 12 provided parallel to the timing rack 10.
2 is connected, for example, to a fuel control lever of a hydraulic governor (not shown). Therefore, when this control lever rotates due to the speed regulating action of the governor, this rotation is transmitted to the main plunger member 3 via the control rack 12 and the control sleeve 11, and the main plunger member 3 rotates by a predetermined amount. Injection amount setting lead 6
The timing when a communicates with the overflow port 2a, that is, the effective stroke, changes, and the injection amount is adjusted.

However, in the injection pump configured as described above, if the timing rack 10 is moved to delay the injection timing, for example, the timing at which the injection timing setting lead 4a closes the timing port 2b is delayed, so as shown in FIG. As can be seen, the injection delay stroke of the plunger 5 increases in proportion to the timing rack position, resulting in a corresponding decrease in the injection amount. As mentioned above, since the control rack 12 is directly connected to the control lever of the governor, due to this decrease in the injection amount, the governor itself performs a speed regulating action and attempts to displace the control rack 12 in the direction of increasing fuel. Due to the temporary large change in the injection amount, the governor could not fully follow it, resulting in an inconvenient hunting situation. Further, the timing rack is normally moved when the type of fuel or engine operating conditions are changed, but since the timing rack 10 and the control rack 12 are operated separately like the injection pump, the timing rack is moved every time the operating conditions are changed. The engine had to be stopped and the timing rack position corrected. In this case, if the control rack actuating link mechanism is provided with a margin in advance for the amount of injection change caused by the movement of the timing rack, the trouble of making corrections each time can be saved, but when the timing rack is moved, the hunting condition described above may occur. Also, due to an inappropriate link ratio, rotation control became generally unstable.

In addition, particularly in marine engines, a method is used to detect the load by detecting the position of the governor's fuel control lever or control rack. Therefore, when adjusting the timing, the control rack responds to the actual load by moving the governor in response to changes in the injection amount. It was not possible to detect the appropriate load. In Figure 4, the vertical axis is the injection amount Q,
It is a static injection amount characteristic diagram with the horizontal axis representing the control rack position R, and shows changes in the injection amount when the timing rack is operated to the delay side. As can be seen from this figure, the maximum injection amount at the control rack position R _Q2 is _Qnax , but the injection amount obtained when the timing rack is moved to the maximum delay side is _Q2 . Therefore, the maximum injection amount Q _nax
In order to obtain this, it is necessary to operate the control rack position from R _Q2 to R _Q3 in the direction of fuel increase. Similarly, at the rack position R _Q0 , the control rack must be moved to the R _Q1 position to increase the amount of fuel injected.
_Q1 had to be compensated.

The present invention has been made to eliminate the various inconveniences mentioned above, and its purpose is to control the control rack in accordance with the displacement of the timing rack to eliminate fuel injection changes during injection timing adjustment, thereby improving engine operation. The objective is to be able to freely change the injection timing depending on the situation.

Next, the present invention will be described with reference to an embodiment shown in FIG.

The timing rack 10 is the fulcrum 1 of the sector gear 13.
3a, the sector gear 13 is driven by a handle 15 with a screw 15a. The timing rack 10 may be automatically operated by other devices to obtain the optimum injection timing for the operating conditions of the engine. The end of the timing rack 10 is a fixed fulcrum 16
A is rotatably attached to a rack correction lever 16 with a pin 10a, and this lever 16 can be rotated by displacement of the timing rack 10 about the fixed fulcrum 16a provided near the other end.
The control rack 12 is connected by a pin 12a to a fuel lever 17, which is connected to the other end of the rack compensation lever 16 by a pin 17a, and to a fuel control lever 19 of a hydraulic governor 18 by a pin 19a. There is.

Therefore, when adjusting the injection timing, operate the handle 15 to move the timing rack 10 from the R _T0 position.
When the engine is moved to the RT _nax position on the lag side, the pin 17a, which is a variable fulcrum between the rack correction lever 16 and the fuel lever 17, moves from the O position to the _O1 position.
Therefore, the fuel lever 17 rotates about the pin 19a, and the control rack 12 moves from the R _Q0 position to the R _Q1 position, and from the R _Q2 position to the R _Q3 position. At this time, 0 ₁ from the 0 position of pin 17a
The movement distance to the position is determined by the fixed fulcrum 16 as described above.
Since point a is provided near the pin 17a which is the variable fulcrum, the movement distance of the control rack 12 is also small.

Generally, the control rack 12 has _RQ0 to _RQ2 .
Or, since it is determined that the timing rack can be moved within the movement control distance range of R _Q1 to R _Q3 , the movement distance of the control rack 12 is smaller than the movement amount of the timing rack 10 as described above. It becomes possible to relatively increase the movement of the timing rack 10, that is, the adjustment margin. This makes it possible to select the timing rack very finely and widely.

Furthermore, the control rack 12 can be displaced in the fuel increasing direction in response to changes in the timing rack 10, independently of the fuel control lever 19 of the governor 18.
There is no need to modify the position at all.

As described above, according to the present invention, in an internal combustion engine equipped with a variable fuel injection timing fuel injection pump, the injection timing can be freely changed without changing the fuel injection amount even in the engine operating state, and the engine control can be carried out easily and reliably.

Furthermore, a fuel lever that connects the control rack and the fuel control lever, and a fixed support point that is connected to the fuel lever at one end and to the timing rack at the other end and located in the middle thereof and near the one end. By connecting the timing rack and the correction lever with the timing rack, it is possible to select the timing rack very finely and widely.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing a variable fuel injection timing fuel injection pump to which the present invention is applied, and FIG. 2 is a right side view of this injection pump.
FIG. 3 is a diagram showing the relationship between the injection delay stroke of the plunger and the timing rack position in the injection pump, FIG. 4 is a static injection amount characteristic diagram of the injection pump, and FIG. It is an explanatory view showing one example. 1: Pump body, 3: Main plunger member, 4:
Sub-plunger member, 4a: Injection timing setting lead, 5: Plunger, 6a: Injection amount setting lead, 10: Timing rack, 12: Control rack, 16: Rack correction lever, 16a:
Fixed fulcrum, 18: Governor, 19: Fuel control lever.

Claims (1)

[Claims] 1 A plunger having a main plunger member having a lead for setting an injection amount and a sub-plunger member having a lead for setting an injection timing; In an internal combustion engine equipped with a variable fuel injection timing fuel injection pump in which plunger members are rotatable by timing racks, a fuel lever connects the control rack and the fuel control lever; and a correction lever which is connected to the timing rack at the other end and has a fixed support point in the middle thereof and at a position close to the one end. A fuel injection timing adjustment device for an internal combustion engine, characterized in that the fuel injection timing can be corrected by moving the fuel control lever without affecting the fuel control lever.