JPS6242143B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a fuel injection pump for an engine.
The present invention relates to a method for adjusting the fuel injection timing of a fuel injection pump having a timer.

The purpose of the present invention is to prevent variations in the set timing of a fuel injection pump with an advance timer at startup, stabilize the fuel injection timing in the normal engine rotation range, and improve engine performance and purify exhaust gas. That's true.

In the fuel injection pump drive device, as shown in Fig. 1, there are a camshaft of the fuel injection pump,
A drive shaft connected to a timing gear of an engine is connected via a coupling ring 3 with a timer 4, a timing scale 6 is provided on the casing of the fuel injection pump 1, and a setting mark 5 is engraved on the timer 4 side.

The timer 4 has a starting advance angle timer, and as shown in Fig. 2, when the engine speed is in the low rotation range, the advance angle is large as shown by arrow A, and in the normal rotation range, it is advanced as shown by arrow B. It is known that the advance angle is controlled to a maximum retard angle with a small advance angle as shown in FIG. That is, the fuel injection timing is early in the low rotation range, delayed in the normal rotation range, and earliest in the high rotation range.

Conventionally, in the timer 4 having such characteristics, the marking point of the alignment mark 5 is located at the arrow A in FIG.
This was done at the stopping position. As a result, the set timing in the normal rotation range is set at arrow B1 in Fig. 2.
Variations occur as in This variation causes problems with engine performance and an increase in smoke in exhaust gas.

The present invention relates to a fuel injection timing timing method that eliminates the above-mentioned conventional problems, and the method is such that the timing mark 5 stamped on the timer 4 is reached at the maximum retardation time in the normal rotation range. .

As a result, as shown in FIG. 3, there is no variation in the set timing in the normal rotation range as indicated by arrow B, and a stable injection timing is obtained. In exchange for this variation in the normal rotation range being eliminated, there will be variation in timing in the low rotation range below idling, but this variation in this range will not have a negative effect on engine performance or exhaust gas, so it can be ignored. be able to.

As described above, according to the method of the present invention, the maximum retard angle can be stabilized in the normal rotation range during operation, and the set timing alignment precision can be improved to improve engine performance and reduce exhaust gas. This improves the effectiveness of using a timer with a starting advance angle.

[Brief explanation of the drawing]

Figure 1 is a perspective view of the fuel injection pump, Figure 2 is a curve diagram showing the relationship between engine speed and advance angle (fuel injection timing) when the alignment mark is hit using the conventional method, and Figure 3 is a diagram of the actual fuel injection pump. FIG. 3 is a curve diagram showing the relationship between engine speed and advance angle (fuel injection timing) according to the invention method. 1... Fuel injection pump, 2... Timing gear, 3... Coupling, 4... Timer, 5...
... Alignment mark, 6... Timing scale.

Claims (1)

[Claims] 1. In a fuel injection pump with a timer, the advance angle is large when the engine speed is in the low rotation speed range, the advance angle is the maximum retardation angle with a small advance angle in the normal rotation range, and the fuel injection pump is controlled to the maximum advance angle in the high rotation speed range. A method for timing fuel injection timing, characterized in that a timing mark on a timer side for matching with a timing scale provided on a casing of an injection pump is stamped at the maximum retard time.