JPH0349044B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a means for detecting a reference position of a rotating body, and more particularly, the present invention relates to a means for detecting a reference position of a rotating body. It is an object of the present invention to provide a means for simultaneously detecting information regarding the reference position of the body.

[Prior art]

In detecting the rotation of a rotating body such as a crankshaft of an internal combustion engine, it is necessary to extract angular information about the rotating body as well as a specific angular position of the rotating body as a reference position.
For this reason, it is common practice to install the means for generating angle information and the means for generating reference position information independently, but this is especially true when the configuration of the control device must be simplified to reduce size and cost. Therefore, it is well known that a method has already been proposed in which information regarding the reference position is also incorporated into the angle information generating means. Various concrete means for this purpose have been proposed, such as in Japanese Patent Application Laid-Open No. 57-137627, but basically, some kind of information is applied to only one specific point among the plurality of angle information provided around the rotating body. This is achieved by creating non-uniformity.

[Purpose of the invention]

Among these general means, the present invention is particularly directed to a method of incorporating reference position information into the angle information by expressing the non-uniformity as angular non-uniformity of the angle information. The present invention provides a simple and highly reliable reference signal detection means.

Furthermore, when detecting angular irregularly spaced parts from among pulse time interval fluctuation patterns in the pulse time series, conventionally only part of the fluctuation pattern caused by the irregularly spaced parts is subject to determination. In particular, since a method of detecting irregularly spaced portions was used, there was a good possibility of erroneous detection due to fluctuations in the rotation of the rotating body.

Therefore, by further proposing a method for detecting irregularly spaced parts in which the entire pattern of fluctuations caused by the irregularly spaced parts of the present invention is determined, an even more reliable means for detecting the reference position of a rotating body can be achieved. It provides:

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

FIG. 1 shows a block diagram of an embodiment of the configuration of an angle information generating means and a control device, which are the object of the present invention. Reference numeral 101 denotes an angular information generating means, which includes, for example, a magnetic rotating body 102 having a plurality of protrusions on its circumference that serve as angle information sources, and an angular position detector located near the rotating body to detect passage of the protrusions. It consists of an electromagnetic pick-up sensor 103 that forms a container,
A pulse time series output 104 of angle information of the rotating body is output. Reference numeral 105 denotes a control device that executes some kind of control upon receiving the pulse time series signal 104, for example, a circuit 106 that shapes the waveform of the pulse time series signal 104, and a circuit 106 that receives the circuit output 107 and performs measurement, calculation, and execution processing. It consists of a one-chip microcomputer 108 that performs the control, and an amplifier 110 that receives the output 109 of the microcomputer and outputs a final control output 111. Furthermore, the rotating body 102 has a configuration as shown in FIG. 2, for example, in order to provide information on reference positions other than angle information. That is, there is one unevenly spaced part with θ ₀ =90° for each equally spaced part with θ ₁ =θ ₂ =θ ₃ =θ ₄ =θ ₅ =θ ₆ =45°.

Now, as the most common conventional example, the method used by the microcomputer 108 to detect the unevenly spaced portion θ ₀ , that is, the reference position from the pulse time series signal 107 of angle information is shown in FIGS. 3 to 3. This is explained in Figure 6. FIG. 3 shows the procedure. A is the waveform of the pulse time series signal 107 that is input to the microcomputer 108 when the rotational speed of the rotating body is constant, and B is the waveform of the programmable timer function built into the microcomputer 108. The i-th pulse time interval Ti of the pulse time series thus measured is plotted every time a pulse is generated. However, a double plot is applied to the pulse time interval Ti corresponding to the unequal interval portion _θ6 , and the same applies hereafter. One of the basic ideas in the traditional method
One is to calculate the fluctuation of the pulse time interval on the pulse time series that appears due to the unevenly spaced part θ ₆ as a ratio of the pulse time interval.
It is determined by Ti/Ti _-1 and detected under the condition that the ratio Ti/Ti _-1 is larger than a given uneven interval judgment value k. The result of performing the above processing on FIG. 3B is shown in FIG. 3C. If k = 1.5, Ti/Ti _-1 = 2 only at the position of the unevenly spaced part θ ₆
Therefore, k<Ti/Ti _-1 , and the unevenly spaced portion θ ₆ can be detected.

In the above explanation, the rotational speed of the rotating body is assumed to be constant, but problems arise when the rotational speed fluctuates. Figure 4 takes the crankshaft of a specific internal combustion engine as a specific example of a rotating body, and explains how the above-mentioned conventional processing method responds in the vicinity of the internal combustion engine starting from the point when the starter is turned on, where the rotational fluctuations are particularly severe. This is what is shown. However, the top dead center of a certain cylinder of the internal combustion engine corresponds to when the protrusion 7 in FIG. 2 faces the electromagnetic pickup sensor 103. Figure 4A is a plot of the pulse time interval Ti every time a pulse is generated, and Figure 4B is the result of the above-mentioned conventional processing.When k = 1.5, 201 and 202
This results in a false detection.

The reason for false detection in conventional methods is that when extracting the pattern of fluctuations caused by the uneven interval θ ₆ from among the fluctuations in the pulse time interval Ti of the pulse time series, the entire pattern of fluctuations is This is because the image is not captured. That is, in the above example, only the process of increasing from the equally spaced part θ ₅ to θ ₆ is attempted to be captured. Therefore, if a sudden acceleration occurs and no significant increase appears in the pulse time interval occurring on the time axis, an erroneous detection will occur.

Therefore, the present invention aims to essentially improve the reliability of reference position detection by capturing the entire pattern of fluctuations caused by the unevenly spaced portion θ ₆ .

Specific examples according to the present invention are shown in FIGS. 5 and 6.
FIG. 5 shows the principle. A in the figure is the same as that shown in B in FIG. The overall picture of the pattern of fluctuations caused by the unevenly spaced part θ ₆ is as follows, immediately after the pulse time interval increases once near the unevenly spaced part θ ₆ .
It is represented by the shape of decreasing again. A relatively simple example of a discriminant function f that digitizes such a convex shape is a discriminant function f= where variables are three pulse time intervals Ti _-2 , Ti _-1 , and Ti that occur continuously. (Ti _-1 ) ² / (Ti _-2 ×Ti) can be completed. The discriminant function f is a function that takes a larger value as the values of Ti _-2 , Ti _-1 and Ti become more convex. B in FIG. 5 shows the results of processing the fluctuations shown in A in the figure using the method described above. If a large value is taken only at the position of the uneven interval θ ₆ and, for example, k=2, the uneven interval θ ₆ can be detected under the condition that k≦f.

FIG. 6 shows the results of applying the processing method according to the present invention to conditions similar to those in FIG. 4, that is, around the time when the internal combustion engine starts to start after the starter is turned on. As a result, evenly spaced parts and unequally spaced parts are clearly separated from the chaotic pulse time interval fluctuation 3, and it can be seen that if k=2, the unequally spaced part can be detected by k≦f. . It can be said that the reliability is much higher than the conventional method.

What is essentially different from the conventional method is that
The following points apply. If you change the acceleration in a certain direction,
In the conventional method, by increasing the number of protrusions, that is, by decreasing the angular interval between the protrusions, it is possible to raise the upper limit of acceleration without false detection, but in principle there is a finite upper limit. Inevitable. However, in the method according to the present invention, if the acceleration is in a constant direction, it is possible in principle to accurately detect unevenly spaced parts even for infinite acceleration. Even if the pulse time interval Ti _-2 immediately before the pulse time interval Ti -1 corresponding to the unevenly spaced part becomes Ti _-2 > Ti _-1 due to intense acceleration, the pulse time interval that occurs after that pulse time interval Ti _-1 Ti becomes extremely small due to intense acceleration, resulting in Ti ² / (Ti _-1 ×
This is because Ti + ₁ ) will take a large value. The same can be said about deceleration in a certain direction.

Next, in the specific example of the present invention described above, the procedure of processing executed within the microcomputer will be explained with reference to the flowchart of FIG.

The processing shown in this flowchart is executed as part of the interrupt processing that is activated every time a pulse of the angle information signal 107 is supplied to the microcomputer.

First, in step S700 corresponding to the pulse time interval measuring means of the present invention, the time interval T between the immediately preceding pulse and the preceding pulse is determined. Next, in step S701, a flag FGPOS stored in the state is determined to determine whether the reference position has already been detected. FGPOS is set to 1 when the reference position has already been detected, and 0 when the reference position has not yet been detected, and is particularly set at the time of power-on reset of the control device 105.
FGPOS=0. Therefore, if the reference position is to be detected from now on, the process branches to FGPOS=0 processing. Therefore, in step S702 corresponding to the pulse time storage means of the present invention, the data of Ti _-2 , Ti _-1 , and Ti are updated every time a pulse is generated, and in step S703, the number of pulse inputs after power-on reset is 4. In other words, from the time when the data of Ti _-2 , Ti _-1 and Ti are completely collected, f is calculated every time a pulse is input in step S704 corresponding to the discriminant function calculation means of the present invention. In step S705 corresponding to the determining means of the present invention, if f<k
If so, it does not correspond to the reference position, but if f≧k, it means that it corresponds to the reference position, and it is only then that it becomes clear to which protrusion of the rotating body the input pulse corresponds. As shown in FIG. 2, each protrusion is assigned a number from 1 to 7, and the pulse from which protrusion is currently input is associated as a variable n in the computer. The numbering of pulses n on the time axis is shown in A of FIG. In this case, when f≧k, Ti _-2 is set to n=6 in step S706.
The time interval Ti _-1 between and 7 is the time interval between n = 7 and 1, and Ti is the time interval between n = 1 and 2, so n = 2, and the reference position This means that we have been able to deal with this. Then, in step S707, a flag FGPOS is set to remember that the reference position has been detected.

After FGPOS is set, every time a pulse is input, T is determined in the same way, and then the process branches to FGPOS=1. First, in step S708, the pulse number n is incremented by 1. In this case, n≧8
If so, replace it with n=n-7. Next, in step S709, if n=
If it is 7, go to step S710 and set T to Ti _-2
If n=1, T is set in step S712.
Ti _-1 and if n=2, step S714
Then, T is substituted for Ti, and at the time of n=2, the reference position is checked as described below. However, this process is to increase the reliability of the control device, and if it is guaranteed that once the reference position is detected, it will never malfunction due to noise etc., then checking the reference position is not necessary. do not have.

First, in step S715, the discriminant function f is calculated,
Next, in step S716, if f≧k, it is assumed that there is no error in the correspondence between the reference positions and the process is terminated; if f<k, an error has occurred in the correspondence between the reference positions due to some cause such as noise. Then, in step S717, FGPOS is set to 0, thereby instructing to start the reference position and detection program again.

Now, regarding the load on the microcomputer when performing the calculation f = (Ti _-1 ) ² / (Ti _-2 ×Ti), it is difficult to understand that microcomputers now include multiplication instructions. , is common, and furthermore, by setting k = 2, 4, 8, etc., division can be replaced with register bit shift instructions and subtraction, so overall the processing load is much lower than that of the conventional method. It never gets bigger.

Therefore, it can be said that the present invention can provide a reference position detecting means that is far more reliable than the conventional ones against rotational fluctuations by using relatively simple means and arithmetic processing.

In addition, the discriminant function f of this embodiment is further simplified and f
=Ti _-1 /Ti _-2 ×Ti _-1 /Ti is also practically possible.

Furthermore, although the unequal spacing of the rotating body shown in the above embodiment was such that only one portion had a relatively larger angle than the other portions, other unequal spacing could be used. An equivalent method can also be devised for

As shown in Figure 8, the distribution of protrusions on the rotating body is θ ₁ = θ ₂ =
θ ₃ = θ ₄ = 90° If the projection is located at a distance of θ ₀ << θ ₁ from other projections, that is, only one part is relatively small compared to the other parts. When the pulse time interval is small, considering the property that the pulse time interval fluctuation increases again immediately after decreasing, the function f
As f=Ti _-2 ×Ti/(Ti _-1 ) ² or its simple form f=Ti _-2 /Ti _-1 +Ti/Ti _-1 can be taken.

Also, as shown in FIG. 9, θ ₁ = θ ₂ = θ ₃ = θ ₄ θ ₁ = θ ₂
＝θ ₃ ＝θ ₄ ＝In addition to the protrusions equally spaced at 45°, there is only one θ ₀
When the protrusions are arranged in the relationship of = 1/2θ ₈ , the fluctuation in the pulse time interval will once decrease, then the pulse time interval will continue to decrease, and then it will increase again. Therefore, the function f has four consecutive pulse time intervals ti _-3 , ti _-2 ,
With ti _-1 and ti as variables, f=Ti _-3 ×Ti/(Ti _-2 ×
Ti _-1 ). It is also possible to simplify this to f=Ti _-3 /Ti _-2 +Ti/T _-1 .

〔Effect of the invention〕

As described above, the present invention provides a convex shape in which the time intervals of three or more consecutive pulses caused by the unevenly spaced portion increase once and then decrease, or conversely, a concave shape in which the time interval decreases once and then increases. By quantifying the engine speed and making it the subject of judgment, it is possible to not only reliably detect the reference position even during deceleration without calculating the engine speed in advance, but also detect parts that are not at the reference position during excessive acceleration. This has the excellent effect of making it possible to detect the reference position of the rotating body with extremely high reliability without erroneously detecting the reference position as the reference position.

[Brief explanation of drawings]

Fig. 1 is a block diagram of an embodiment of the present invention, Fig. 2 is a schematic diagram of the angle information generating means, Fig. 3 is a characteristic diagram showing a conventional reference position detection method, and Fig. 4 is a conventional reference position detection method. FIG. 5 is a characteristic diagram showing the reference position detection method of the embodiment of the present invention.
FIG. 6 is a characteristic diagram showing three cycles of the reference position detection method according to the embodiment of the present invention, FIG. 7 is a flowchart showing the reference position determination process, and FIG. 8 is a diagram showing the second embodiment of the angle information generating means. Figure 9 shows the third angle information generating means.
It is a figure showing an example. 101... Angle information generating means, 102... Magnetic rotating body, 103... Electromagnetic pickup, 105...
...Control device, 106...Waveform shaping circuit, 108...
...1-chip microcomputer, 110...amplifier.

Claims (1)

[Scope of Claims] 1. A rotating body that forms information regarding angular position on its circumference, an angular position detector for detecting information regarding the angular position of this rotating body, and an angle generated by this angular position detector. and an electronic control unit that receives signals and executes control processing of the internal combustion engine, and the information regarding the angle of the rotating body includes angle information giving angular positions at equal intervals on the circumference, and part of the information giving angular positions at equal intervals on the circumference. and reference position information provided by unevenly spaced parts that are larger or smaller than the angular width of the angular information, and the electronic control device is configured to perform the angular information according to the information regarding the angle as the rotating body rotates. A time series of time intervals of angle pulses generated is sequentially inputted to an angle detector, and a pulse time interval measuring means for measuring the time intervals of the angle pulses and a time series of time intervals measured by this pulse time interval measuring means are input. a pulse time storage means for storing three or more consecutive pulse time intervals; and a pulse time storage means for storing three or more consecutive pulse time intervals; Calculate the discriminant function f that quantifies the convex shape in which the pulse time interval increases and then decreases, or conversely the concave shape in which the pulse time interval decreases and then increases. and determining means for comparing the discriminant function f and an uneven interval determination value k to determine whether or not the reference position information of the rotating body has passed through the angular position detector. A reference position detection device for an internal combustion engine, characterized in that: 2. The reference position information is composed of unevenly spaced portions that are larger than the angular width of the equally spaced angle information, and the pulse time storage means stores a time series of time intervals measured by the pulse time interval measuring means. Three consecutive pulse time intervals Ti _-1 ,
Ti _-2 , Ti, and the discriminant function calculating means calculates the discriminant function f=(Ti _-1 ) ² /(Ti _-2 ×Ti)
Alternatively, f=Ti _-1 /Ti _-2 +Ti _-1 /Ti is calculated to quantify the convex shape in which the pulse time interval increases once and then decreases, and the determination means determines that f>k. The reference position detection device for an internal combustion engine according to claim 1, wherein the reference position detection device for an internal combustion engine is determined to be the reference position when the reference position is reached. 3. The reference position information consists of irregularly spaced portions that are smaller than the angular width of the equally spaced angular information, and the pulse time storage means stores a time series of time intervals measured by the pulse time interval measuring means. Three consecutive pulse time intervals Ti _-2 ,
The discriminant function calculation means stores the discriminant function _f =(Ti _-2 ×Ti)/(Ti _-1 ) ²
Alternatively, f = Ti _-2 / Ti _-1 + Ti / Ti _-1 is calculated to quantify the concave shape in which the pulse time interval once decreases and then increases, and the determination means is used to determine if f>k. The reference position detection device for an internal combustion engine according to claim 1, wherein the reference position detection device for an internal combustion engine is determined to be the reference position when the position of the reference position is determined to be the reference position. 4. The reference position information consists of unevenly spaced portions that are twice consecutively smaller than the angular width of the equally spaced angular information, and the pulse time storage means stores the time measured by the pulse time interval measuring means. Four consecutive pulse time intervals from a time series of intervals
It stores Ti _-3 , Ti _-2 , Ti _-1 , Ti,
The discriminant function calculating means calculates the discriminant function f=(Ti _-3 ×
Ti) / (Ti _-2 × Ti _-1 ) or f = Ti _-3 /Ti _-2 +
Ti/T _-1 is calculated to quantify the concave shape in which the pulse time interval once decreases and then increases, and the determination means determines the reference position when f>k. A reference position detection device for an internal combustion engine according to claim 1.