JPH0130622Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a crank angle detection sensor for an internal combustion engine, which is suitable for use in an ignition device of an internal combustion engine.

As is well known, internal combustion engines are powered by the explosive force generated when compressed fuel is ignited. In this case, since the engine output changes depending on the ignition timing, ignition is performed at the optimal timing.

FIG. 1 is a sectional view showing an example of a conventionally used sensor. In the figure, 1 is a shaft that is driven by the engine and rotates, 2 is a photoelectric detection unit that detects the cylinder position and rotation angle of the engine, respectively, and 3 is a rotary plate that generates rotation information and cylinder information of the shaft 1. It is. The rotary plate 3 is shown in detail in FIG. 2, and 4 is a cylinder slit drilled at a predetermined position so that the detection unit 2 can detect a reference position corresponding to the cylinder of the engine, and 5 is a cylinder slit for detecting the rotation angle of the engine. In order to do this, angular slits are bored at equal intervals near the outer periphery of the rotary plate 3. The cylinder slit 4 is larger than the angular slit 5 as shown in FIG.
The end of the other angular slit 5 coincides with the end of this cylinder slit 4.

The operation of the conventional sensor configured as described above is as follows. Detection part 2 of crank angle detection sensor
The angle slit 5 detects the angle signal shown in FIG. 4A, and the cylinder slit 4 detects the cylinder signal shown in FIG. 4B. By supplying the cylinder signal and the angle signal to an ignition device (not shown), the ignition device sets the optimum ignition timing.

However, with such conventional sensors, it is extremely difficult to determine the timing of cylinder signal generation without error in correspondence with the actual cylinder, and the ignition system compares the change points of both the cylinder signal and the angle signal. Since the ignition timing is determined by the ignition timing, if there is an error in the timing when the cylinder signal is generated, a timing error corresponding to a half cycle of the angle signal may occur, which has the drawback that the optimum ignition timing may not be obtained.

Therefore, the purpose of this invention is to develop a crank angle detection sensor for an internal combustion engine that generates a cylinder signal and an angle signal that allows the ignition system to determine the optimal ignition timing even if there is some error in the cylinder signal generation position. It is about providing.

In order to achieve this purpose, this idea
The change point of the cylinder signal is made to occur near the center of the angle signal duration period. This invention will be explained in detail below using drawings showing embodiments.

FIG. 5 is a partial plan view of the rotating plate 3 showing an embodiment of this invention, and the same symbols are used for the same parts and corresponding parts as in FIG. 3. In the figure, the left end of the cylinder slit 4 is located at the center of the perforated part of the angular slit ₅₁ , and the right end of the cylinder slit 4 is located at the center of the non-slit portion between the adjacent angular slits ₅₂ and ₅₃ . are doing. In addition, the angle slit 5
For convenience of explanation, three slits 5 ₁ to 5 ₃ are shown, but in reality they are drilled all around the circumference, and the cylinder slits 4 are also drilled by the number of cylinders, and the angular slits 5 ₂ ,
5 ₃ may be any slit as long as it is adjacent.

The operation of the sensor according to the invention configured as described above is as follows. The detection section 2 of the crank angle detection sensor detects the angle signal shown in FIG. 6A through the angle slit 5, and the cylinder signal shown in FIG. 6B through the cylinder slit 4. At this time, since the cylinder slit 4 and the angle slit 5 have a positional relationship as shown in Figure 5, the cylinder signal changes near the center of the angle signal duration period as shown in Figure 6. .

Therefore, even if there is a slight error in the generation timing of the cylinder signal, as long as the change point of the cylinder signal is within the range of the arrow in Fig. 6A, the change point of the cylinder signal and the change point of the angle signal will be the angle The error is limited to one quarter of the signal cycle, and the detection accuracy is twice as high as that of the conventional method.

In addition, even if the rotary plate 3 is fixed to the shaft 1 with the front and back sides reversed, the distance from the cylinder signal change point to 1/4
Since the same angle signal is generated after each period, there is no mounting directionality between the front and back, and there is no need to be careful when mounting the rotary plate 3, which improves productivity.

In addition, although the above explanation assumes that the detection unit is a photoelectric type,
Of course, it is also possible to provide a slit in a metal rotary plate and detect the presence or absence of the slit using a proximity switch or the like.

As explained above, in the crank angle detection sensor for an internal combustion engine according to this invention, the change point of the cylinder signal is set at the center of the angle signal duration period, so that the influence of errors at the time of cylinder signal generation on the angle signal can be reduced. It has excellent effects.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing an example of a conventional crank angle detection sensor, Fig. 2 is a plan view of a rotating plate, Fig. 3,
FIG. 5 is a partial plan view of the rotating plate, and FIGS. 4 and 6 are waveform diagrams. 1... Shaft, 2... Detection section, 3... Rotating plate, 4... Cylinder slit, 5... Angle slit.

Claims (1)

[Scope of utility model registration request] A rotating plate fixed to a shaft rotationally driven by an internal combustion engine, angular slits drilled at equal intervals around the periphery of the rotating plate, and angular slits drilled at predetermined positions different from the angular slits. having a cylinder slit having a width greater than the width of the angular slit;
In a crank angle detection sensor for an internal combustion engine that detects the crank angle depending on the presence or absence of these slits,
One end of the cylinder slit provided on the rotary plate is made to coincide with approximately the center of the perforated portion of any angular slit, and the other end is made to coincide with approximately the central portion of the non-slit portion between any adjacent angular slits. Characteristic crank angle detection sensor for internal combustion engines.