JPH02541B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of setting fuel injection timing for an internal combustion engine.

Conventionally, the injection timing was set by aligning a pointer attached to the flywheel housing or the engine body with the 1st cylinder injection start mark engraved on the flywheel or crank pulley, as shown in Figures 1 and 2. Next, after installing it on the engine, the engine side and the fuel injection pump side were connected via a coupling hole by matching the stamp A on the fuel injection pump body A and the stamp D on the automatic timer mah.

By matching the engraving B on the fuel injection pump body A with the engraving D on the automatic timer, the plunger that injects fuel into the first cylinder will be in the position where the spill port is exactly closed and compression begins. It is set.

By the way, in the conventional injection timing setting, the markings A on the fuel injection pump body and the markings D on the automatic timer mah were visually aligned, and as shown in Figure 2 a and b, there was a difference in feeling between workers. Discrepancies occur due to misalignment, making it impossible to obtain an appropriate injection timing.

Therefore, even if the engine is of the same model, the exhaust gas,
This resulted in variations in performance such as output and fuel efficiency.

The present invention aims to provide a method for setting the fuel injection timing without variation, and the injection start position on the fuel injection pump side, where the spill port has been closed by the plunger of the fuel injection pump, is set to the injection start position on the side of the fuel injection pump, and the injection timing is set by the injection start position on the side of the fuel injection pump, where the spill port is closed by the plunger of the fuel injection pump. The setting is made by checking the fuel to be used, and in order to maintain this setting state, a fixed member is rotated integrally with the fuel injection pump body and the camshaft by straddling the fuel injection pump body and a member that rotates together with the camshaft. After fixing the camshaft by attaching it to a member that rotates integrally with the fuel injection pump body and the camshaft, and installing the device in an engine in this state, remove the central part of the fixing member to release the fixed state between the fuel injection pump body and the member that rotates integrally with the camshaft. This is a fuel injection timing setting method for an internal combustion engine, characterized in that:

The present invention will be explained with reference to FIGS. 3 to 8.
First, in a pump tester (not shown) or the like that measures the performance of the fuel injection pump 1 itself, the camshaft 3 to which the automatic timer 2 is attached is rotated by rotating the automatic timer 2. The plunger, which is moved up and down by the cam 3a, is raised to bring the plunger 4, which injects fuel into the first cylinder, to the injection (compression) starting position. That is, as shown in the fourth figure, the top portion 4a of the plunger 4 comes to the position immediately after closing the spill port 5. In this position, when the plunger 4 does not close the spill port 5, fuel passes from the fuel gear gallery (not shown) through the spill port 5 and pushes up the delivery valve (not shown) from the pressure chamber 6 as shown by the arrow in FIG. This can be confirmed because the outflow of fuel stops when the top 4a of the plunger 4 closes the spill port 5.

Next, the camshaft 3 is fixed so as to maintain the position, that is, to prevent the camshaft 3 from rotating.

For example, as shown in FIGS. 5 and 6, a means for this fixation is to straddle the bearing support portion 7 of the camshaft 3 of the fuel injection pump 1 and the automatic timer 2 that rotates together with the camshaft 3. A plate-shaped fixing member 8 is attached and fixed to the bearing support portion 7 and the automatic timer 2 using setscrews 9, 10, etc.

Note that when the fixing member 8 is pulled by holding the annular piece 11 as shown in FIG.
is removed so that the fixed state can be easily released when the fuel injection pump 1 is finally installed.

The fuel injection pump 1 whose injection start position has been fixed in this manner is fixed to the engine in the same manner as in the prior art, and is mounted on the engine in the same manner as in the prior art. That is,
After setting the injection start position on the engine side by aligning the pointer 14 attached to the flywheel housing 13 with the first cylinder injection start mark 16 engraved on the flywheel 15, the engine side pump drive shaft 17 and automatic timer are set. 2 are connected by a coupling 18.

In this case, since the coupling ring 18 has an adjustment allowance as is well known, it can be mounted in the same manner as in the conventional case even if the engine side and the fuel injection pump 1 side are fixed at the injection start position.

After doing this, if the bearing support part 7 and the automatic timer 2 are released from each other, the automatic timer 2 can be operated.

The present invention focuses on the injection start position of the fuel injection pump, that is,
The position immediately after the top part 4a of the plunger 4 finishes closing the spill port 5 is detected by checking the fuel flowing out through the delivery valve, and this state is fixed by the fixing member 8, and the engine starts injection. Since the period is set, it is possible to reduce wide variations compared to the conventional method of setting the markings by visual inspection.

In this embodiment, the fixing member 8 is placed across the bearing support portion 7 of the camshaft 3 and the automatic timer 2 to prevent the rotation of the camshaft 3. In this case, it is sufficient to fix the fixing member by straddling the camshaft's coupling flange and the bearing, and it is possible to prevent the camshaft from rotating so that the top of the plunger maintains the state immediately after closing the spill port. It's a good thing.

Since the present invention is a method of setting fuel injection timing without variation, it is possible to create an engine without variation in exhaust gas, output, fuel efficiency, etc.

[Brief explanation of drawings]

Fig. 1 is a side view of the main part showing the conventional means, Figs. 2 a and b are explanatory diagrams showing the injection timing adjustment process as the conventional means, and Figs. 3 to 8 show an embodiment of the present invention. Fig. 3 is a cross-sectional view of the main part showing the relationship between the plunger and the spill port, Fig. 4 is an enlarged view of the main part of Fig. 3, Fig. 5 is a side view of the main part showing the fixed state of the camshaft, and Fig. 6 is a sectional view of the main part showing the relationship between the plunger and the spill port. 7 is a side view of a main part showing the state of fuel injection timing setting in the internal combustion engine, and FIG. 8 is a front view showing the state after the fixing state by the fixing member is released. 1... Fuel injection pump, 2... Automatic timer, 3... Camshaft, 4... Plunger, 5...
... Spill port, 6 ... Pressure chamber, 7 ... Bearing support section, 8 ... Fixing member, 9, 10 ... Set screw, 11
... Ring piece, 12 ... Center part, 13 ... Flywheel housing, 14 ... Pointer, 15 ...
Flywheel, 16...mark, 17...pump drive shaft, 18...coupling.

Claims (1)

[Claims] 1. Set the injection start position on the fuel injection pump side after the spill port has been closed by the plunger of the fuel injection pump by checking the fuel flowing out through the delivery valve. After fixing the camshaft by installing a fixing member across the pump body and the member that rotates together with the camshaft, and installing it in the engine in this state,
A method for setting fuel injection timing for an internal combustion engine, characterized in that the fixing state between the fuel injection pump body and a member that rotates integrally with the camshaft is released by removing a central portion of the fixing member.