JP2003166821A - Angle measuring apparatus or rotational frequency measuring apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an angle measuring apparatus or a rotational frequency measuring apparatus accurately detecting a measured value and a corresponding method for measuring an angle or a rotational frequency of a shaft more accurately in regard to an angle measuring apparatus or a rotational frequency measuring apparatus having a signal generator arranged on a shaft of an internal combustion engine, for example, a signal generator arranged on a crankshaft of an automobile, and of a type where the signal generator has a multiplicity of annularly arranged markings and a sensor co-operating with the signal generator, the markings are respectively separated increments and an angle or rotational frequency to be measured is detected on the basis of a sensor signal and increment duration. <P>SOLUTION: A unit detecting corrected increment duration with respect to a momentary increment in consideration of increment duration of a reference increment is provided on the angle measuring apparatus or the rotational frequency measuring apparatus by a superordinate concept. The increment duration of the reference increment is already known from precedent evaluation. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an angle measuring device or a rotational speed measuring device according to the general concept of claim 1, which detects an angle or a rotational speed to be measured based on a sensor signal and an increment duration. It also relates to a correction method for an instantaneous increment duration according to the preamble of claim 9.

[0002]

BACKGROUND OF THE INVENTION Angle or speed measuring devices are used, for example, in motor vehicles to detect the angular position or speed of a crankshaft or camshaft.
In this case, the angle measuring device or the rotational speed measuring device typically comprises a signal generator arranged on the shaft, which has a number of markings, and a sensor which cooperates with this signal generator. The markings are increments that are spaced apart from each other.

The sensor can be a capacitive sensor, an inductive sensor, an optical sensor, or any other common sensor. Correspondingly, the markings provided on the signal generator are electromagnetic elements, protrusions or, for example, gear teeth.

FIG. 1 shows a known angle measuring device. Here, it is shown that the angle measuring device is used, for example, in an automobile to detect the angular position of a crankshaft. The angle-measuring device shown has a signal-generating wheel 2 arranged on a crankshaft 1. A large number of teeth 3 are provided on the peripheral surface of the signal generating wheel 2.
Are arranged, and these pass the sensor 4 in the direction of the arrow. The markings or teeth 3 are arranged at regular intervals from one another. The step width of marking 3 is shown as increments (i, i + 1, i + 2).

With such a construction, the angle or the rotational speed of the shaft 1 is detected on the basis of the edge signal and the so-called increment duration. This increment duration is the time between two pulses formed by the sensor 4, i.e. one increment i (increment from one rising edge to the next rising edge or from one falling edge to the next). The increment to the falling edge) is the time required to pass the sensor 4. Therefore,
If the increment i is set to 6 °, for example, the instantaneous angular position or rotational speed of the shaft 1 can be easily calculated.

Commonly used signal generators have a relatively small number of markings (teeth). For example, the typically used signal-generating wheel 2 has only 60 or 120 teeth 3 as shown in FIG. 1, so that it is not possible to detect the angle or rotation speed precisely.

The angular position between two successive markings or tooth edges 3 is therefore usually extrapolated by the increment duration of the preceding increment (i-1). That is, the increment duration in the instantaneous increment (i) is always the "old" increment duration that comes from the immediately preceding increment (i-1).

In the embodiment of FIG. 1, this means the following. That is, after the increment i has passed the sensor 4, the increment duration belonging to this increment (i) is also the basis for the increment i + 1. Therefore, if the acceleration between the two increments is large (both positive and negative), then considerable measurement errors that can no longer be tolerated can result.

Particularly in the case of internal combustion engines, especially motor vehicle internal combustion engines, relatively large fluctuations in the engine speed are caused by compression or expansion of the cylinders.

FIG. 2 shows a typical example of the course of the engine speed of a four-cylinder engine of a motor vehicle in one engine cycle (each cylinder is ignited once).
By observing the illustrated speed signal of the crankshaft, it can be seen that for each injection (or each ignition), the sine-like speed profile repeats in a considerable number of speed ranges produced by each of the cylinders. Fuel ignition in a cylinder first causes acceleration to the upper peak of the engine and finally deceleration to the beginning of ignition for the subsequent cylinder.

However, this relatively large rotational speed dynamics causes errors in the calculated angular position or rotational speed.

[0012]

SUMMARY OF THE INVENTION Therefore, the object of the present invention is to provide a rotational speed measuring device or an angle measuring device for detecting a measured value accurately, and a corresponding object for more accurately measuring the shaft angle or rotational speed. And how to do that.

[0013]

The above object is to provide an angle measuring device or a rotational speed measuring device according to a superordinate concept in which a unit for detecting a corrected increment duration with respect to an instantaneous increment in consideration of an increment duration of a reference increment. It is solved by providing.
The increment duration of the reference increment is
Already known from previous assessments.

[0014]

DETAILED DESCRIPTION OF THE INVENTION As a reference increment, it is possible to use an increment that can belong to the same cylinder working point as an instantaneous increment. This reference increment can be obtained from the same engine operating cycle as the instantaneous increment, or from the preceding operating cycle.

According to one advantageous embodiment of the invention,
Instantaneous increments and reference increments can occur in exactly one or more engine cycles (shaft rotation m
Corresponding to each other). Therefore, in this case, the increment duration in the same cylinder is detected.

It is also possible to detect the corrected increment duration, optionally taking into account the reference increment in another cylinder. In this case, the instantaneous increment and the reference increment are 1 / k (k = number of cylinders) engine cycles (corresponding to 2 * n / k markings for a normal car crankshaft, n = number of markings in one revolution). Only, or multiples of this, away from each other.

According to one advantageous embodiment of the invention,
The unit for detecting the corrected increment duration also takes into account possibly additionally generated engine acceleration (caused by gas supply or braking). For this purpose, the difference between the increment duration of the first increment and the increment duration of the reference increment or the corresponding difference in the rotational speed is calculated.

Advantageously, the increment duration of the first increment comes from the instantaneous engine cycle and the increment duration of the reference increment comes from the preceding engine cycle.

Also preferably, the first increment, the instantaneous sensor passing increment and the reference increment are the associated increments from the preceding engine cycle.

According to one advantageous embodiment of the invention,
The signal generator is configured as a signal generating wheel with teeth arranged on the circumferential surface.

The measured increment duration or rpm is preferably stored in a memory (RAM).
From this memory, the unit reads out the increment duration or rpm of the reference increment to which it belongs.

[0022]

The invention is explained in more detail below with reference to the attached drawings as an example.

FIG. 1 shows a signal generator 2 arranged on the shaft 1. This signal generator 2 has teeth (marking) 3 arranged in a row on the circumferential surface, and these teeth pass through the sensor 4 in the direction of the arrow.

The arrangement of the signal generator 2 and the sensor 4 is provided with a unit 5 for detecting the corrected increment duration. This unit 5 gives the increment duration for the instantaneous increment (i),
It is calculated in consideration of the increment duration of the reference increment. The increment duration of this reference increment is known.

In the simplest case, the corrected increment duration P _korr (i) or the number of revolutions N of the increment i passing through the sensor 4 instantaneously
_korr (i) is detected as: P _korr (i) = P (i ′ + 1) N _korr (i) = N (i ′ + 1) where the increments i and i ′ are engine cycles 1 / k times (k = the number of cylinders) or a multiple thereof. This also corresponds to the predetermined number of markings 3, which is defined by the step width of the markings 3.

FIG. 2 shows a typical course of the engine speed during the operating cycle of the engine. Here, a sine-like progression of the number of revolutions which is repeated for each injection or each ignition is clearly shown. This process is caused by the expansion and compression of the cylinder.

Points i1 to i3 each indicate an increment corresponding to the same point of action of the cylinder. Therefore, these increments are incremented by i4
Can be used as a reference increment for.

FIG. 3 shows two parts of the engine speed curve for the first cylinder of the internal combustion engine. The sine-shaped curve is the actual rotation speed of the first cylinder, and the step-shaped curve is the rotation speed detected by the measuring device.

As can be understood from this, there is a phase shift between the actual rotation speed and the detected rotation speed. As already explained, this occurs due to the rotational speed detection type.

Observing the embodiment of FIG. 1, the increment duration to which the increment i has passed after passing the sensor 4 is detected, on the basis of which the angle or number of revolutions of the shaft 1 at increment i + 1 is calculated. However, this increment duration is already a thing of the past at this point.

In FIG. 3, it can be seen that the rotational speed N for the increment i ′ can only be used at the increment i ′ + 1, but is significantly lower than the actual rotational speed at the increment i ′ + 1.

Here, in order to correct the increment duration for the instantaneous increment i, the increment duration P (i '+ 1) or the number of revolutions N (of the corresponding reference increment i'which is known from the preceding operating cycle. i '+ 1) is used.

The engine acceleration from the last engine cycle to the instantaneous engine cycle occurs when the increment duration decreases (in this case, when the speed increases by the value a). In order to take the engine acceleration into consideration, finally, the increment duration P of the reference increment i'is
(I '+ 1) or the number of revolutions N (i' + 1), the increment duration P of the immediately preceding increment i-1
The difference between (i) and the increment duration to which the immediately preceding operation cycle P (i ') belongs is added.

Corrected increment duration P
_korr is calculated as follows: P _korr (i) = P (i ′ + 1) + P (i) −P
(I ') For the corrected speed N _korr (i), the following formula applies: N _korr (i) = N (i' + 1) + N (i)-(N
(I ') Phase-corrected increment duration P _korr (i) or rotation speed N _{thus obtained
Korr} (i) is finally used for angle extrapolation.

[Brief description of drawings]

FIG. 1 is an angle measuring device according to an embodiment of the present invention.

FIG. 2 is a graph showing the revolution speed of an automobile during an engine operation cycle.

FIG. 3 shows, in particular, the measured actual speed profile of an individual cylinder.

[Explanation of symbols]

1 shaft 2 signal generator 3 tooth 4 sensor 5 correction unit 6 memory i instantaneous increment _i'already incremented N rotational speed N _korr corrected rotational speed a upward shift of engine speed due to engine acceleration

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 2F069 AA84 DD19 EE23 GG04 GG06                       GG07 GG11 HH13 HH15 NN21                 2F077 AA25 CC02 NN21 NN27

Claims (11)

[Claims] 1. An angle-measuring or speed-measuring device comprising a signal generator (2) arranged on the shaft of an internal combustion engine, for example a signal generator (2) arranged on the crankshaft of a motor vehicle. The signal generator (2) has a number of annularly arranged markings and a sensor (4) cooperating with said signal generator (2), said markings being respectively spaced apart increments. And the angle or number of revolutions to be measured is in the form of being detected on the basis of the sensor signal and the increment duration, the corrected increment duration P _{k orr} (i) for the instantaneous increment (i), Increment duration P (i '+ 1) of reference increment (i')
An angle measuring device or a rotational speed measuring device, which is provided with a unit (5) for detecting in consideration of the above. 2. The angle measuring device or the speed measuring device according to claim 1, wherein the reference increment (i ′) and the instantaneous increment (i) are separated from each other by one or more engine cycles. 3. The reference increment (i ′) and the instantaneous increment (i) are 1 / k of an engine cycle.
An angle measuring device or a rotational speed measuring device according to claim 1, which is separated from each other by a multiple (k = number of cylinders) or a multiple thereof. 4. Corrected increment duration P
Said unit (5) for detecting _korr (i)
Additionally considers possibly generated engine acceleration, in the above case, the increment duration of the reference increment (i′−1) corresponding to the increment duration P (i) of the first increment (i−1). 4. The angle measuring device or the rotational speed measuring device according to claim 1, wherein the difference from the time (Pi ′) is calculated. 5. An angle measuring device or speed measuring device according to claim 4, wherein the reference increment (i'-1) is derived from a preceding engine cycle. 6. The corrected increment duration P _korr (i) for an increment (i) passing through the sensor (4) instantaneously is calculated according to the following formula: Angle measuring device or rotation speed measuring device: P _korr (i) = P (i ′ + 1) + P (i) −P
(I ') 7. The angle measuring device or the rotational speed according to claim 1, wherein the signal generator is a signal generating wheel (2) having teeth (3) arranged on a peripheral surface thereof. Measuring instrument. 8. The angle measuring device or the rotational speed measuring device has a memory (6), and the memory (6) has an increment duration P (i).
Or the number of revolutions N (i) is stored.
An angle measuring device or a rotation speed measuring device according to any one of the above. 9. A method for detecting the angle or number of revolutions of a shaft (1) of an internal combustion engine, for example the angle or number of revolutions of a crankshaft of a motor vehicle, wherein the angle or number of revolutions to be measured is incremented in duration. Of the corrected increment duration P _korr (i ')
_Is considered in consideration of the increment duration P _korr (i ′ + 1) of the corresponding reference increment i ′. 10. Method according to claim 9, wherein the increment duration P (i ′ + 1) of the reference increment (i ′) is read from the memory (6). 11. Method according to claim 9 or 10, characterized in that the possibly occurring engine acceleration is taken into account when the corrected increment duration P _korr (i) is detected.