KR102093195B1 - Method for correcting a measurement signal of a rotating camshaft in an internal combustion engine in a partial load operation - Google Patents

Abstract

The present invention relates to a method for determining the actual angular value of the rotational motion of the camshaft 11 which rotates when the internal combustion engine is in the partial load operating mode, the method comprising a plurality of marking parts 12a, 12b, 12c and 12d ), The sensor wheel 10 includes a sensor wheel that is rotatably connected to the rotating camshaft 11 and the marking parts 12a, 12b, 12c, and 12d of the sensor wheel 10, thereby measuring signals It is performed using a transducer 13 for determining 20, in this method the edge positions 21 of the markings 12a, 12b, 12c and 12d of the sensor wheel 10 based on the measurement signal 20 -28) is determined, the measurement signal 20 is determined at the second perception point, and the edge positions 21-28 at the second perception point are determined based on the measurement signal, and the second perception is The edge positions 21-28 and the internal edge determined from the edge positions 21-28 at the time point at the first advance time point during partial load operation. Based on the relationship between the actual angle of the rotational motion of the camshaft 11 of the engine, the actual angle value of the rotational motion of the camshaft 11 is determined at.

Description

METHOD FOR CORRECTING A MEASUREMENT SIGNAL OF A ROTATING CAMSHAFT IN AN INTERNAL COMBUSTION ENGINE IN A PARTIAL LOAD OPERATION}

The present invention relates to a method for determining the actual angular value of rotational motion of a camshaft that rotates when the internal combustion engine is in a partial load operating mode.

In a four-stroke internal combustion engine, the camshaft generally rotates at half the speed of the crankshaft. Therefore, one rotation (360 ° NW) of the camshaft corresponds to two rotations of the crankshaft with a crankshaft angle of 720 ° KW and one complete combustion cycle of the internal combustion engine. When adjusting the camshaft (also referred to as variable camshaft control), a relative angular offset may occur between the camshaft position and the crankshaft position within a predetermined range. In this case, camshaft control is also usually performed to control the angular offset. To this end, it is necessary to determine the actual position of the camshaft (the actual angular value of the rotational motion of 0 to 720 ° KW), and a sensor wheel can be used for this. Marking parts are attached to the periphery of the sensor wheel. The sensor wheel is fixed non-rotatably on the camshaft, and the markings can be sensed by the transducer. At this time, the electrical signal is generated by the passage of the marking parts and in the transducer, for example, the inductive transducer.

When the marking part passes through the transducer, rising edges and falling edges may be detected in the measurement signal. At this time, for example, the falling edges may have approximately equidistant distances, but the rising edges are not. This structure ensures fast synchronization at startup. The position of the camshaft can be determined based on the edge positions of the measurement signal. At this time, the camshaft position can be detected in units of segments, that is, current angle-based information about the camshaft position is obtained only once or several times for each camshaft rotation. The absolute camshaft position based on the angle is not used at points between segment boundaries. Here, the segment means, for example, a preset range of rotation angles of the camshaft, whose range depends on the number of cylinders.

There are various mechanisms that affect the rotation of the camshaft. For example, in some internal combustion engines, individual cylinders can be completely shut off to save fuel in the low partial load range, and as a result no further combustion occurs in these cylinders. In contrast to the so-called full load operation in which all cylinders are ignited, this operation is referred to as partial load operation. Another example is variable valve lift systems capable of changing the cam shape for each cylinder. In so-called zero lift, the shape of one or more cams is changed in such a way that the associated valves are no longer actuated, so that partial load actuation can be realized.

In such cases, the vibration torque exerted on the camshaft by the valve changes and as a result the vibrational behavior of the camshaft changes. If one of the cams skips a valve of a cylinder that is not ignited, or if the shape of the cam is changed, the rotational motion and rotational speed of the camshaft at the actual angle values are also changed. Therefore, a variable deviation occurs at an angular offset that negatively affects camshaft control.

For this reason, there is a need to provide a method for improving the rotational motion control of the camshaft, especially when one or more cylinders of the internal combustion engine's cylinders are not ignited during partial load operation.

The present invention proposes a method for determining the actual angular value of the rotational motion of a camshaft rotating in an internal combustion engine during partial load operation, comprising the features of claim 1. Preferred configurations are subject to the dependent claims and the detailed description below.

The method according to the invention is used for adaptation of the measuring signal of the camshaft rotating in the internal combustion engine, especially during partial load operation including variable valve lift and zero lift. Preferably this partial load operation is realized by switching the cam shape to zero lift. In this case, the sensor wheel including a plurality of marking portions (eg, a tooth with a plurality of teeth) is non-rotatably mechanically connected to the camshaft of the internal combustion engine. At this time, the sensor wheel performs the same rotational motion as the camshaft. A transducer, such as a magnetic sensor, detects the markings of the sensor wheel to determine a measurement signal, such as a voltage signal. From these measurement signals, the edge positions of the marking portions of the sensor wheel are determined.

Correction is performed at a second late time point that lies behind the first time point. At this time, a measurement signal is determined, and based on this, edge positions at the second time point are determined. From the edge positions at the second time point, the actual angle value of the camshaft rotation of the internal combustion engine is determined based on the relationship determined at the first time point.

Therefore, the present invention preferably includes correction at a second time point during the operation of the internal combustion engine.

Preferably, adaptation is carried out at a first time point, at which time the edge positions determined at the first time point and the actual angle of rotational movement of the crankshaft or camshaft (the reason for this being equivalent, the camshaft angle and the crankshaft angle during adaptation) Is fixed because it has a 2: 1 ratio).

The present invention provides the possibility to improve camshaft control during partial load operation through smoothing of the actual angle determination. The leaps are reduced in the actual angle signal. Surprisingly, this smoothing can be achieved by implementing measures that are substantially equivalent to the so-called segment length adaptation, which is generally carried out in full load operation, even in partial load operation. The reason this is surprising is that, when adapting the segment length, the actual segment lengths (according to the manufacturing process) of the sensor wheel, which do not differ between the original full load operation and the partial load operation, are determined. However, if segment length adaptation is now implemented even in partial load operation, different segment lengths appear here than in full load operation. This is due to rotational non-uniformity in partial load operation as described above, but adaptation is based on uniformity of rotation. Using these segment lengths (actually inaccurate) to compensate for subsequent measurement signals in partial load operation also results in errors in determining the actual angle. The angle hopping that actually occurs is no longer detected when determining the actual angle. Thus, control is improved by no longer having to react to it. This error in determining the actual angle of the camshaft does not adversely affect combustion, since the relevant cylinders are cylinders that are not ignited anyway.

In other words, the method according to the invention provides extended camshaft adaptation, especially for partial load operation, and can be implemented similar to segment length adaptation in full load operation. A novel idea of the method according to the invention is to treat edge positions in partial load operation as a unique sensor wheel dedicated to partial load operation. Displaced edge positions and segment lengths compared to full load operation due to the effect of vibration torque in partial load operation, the spacing of the edge positions are considered as the edge positions and segment lengths of the marking portions of the virtual sensor wheel.

In this adaptation, the edge positions are detected at the reference stop, in the case of deactivation of the camshaft control or in the overrun mode, so that the actual intervals of the individual edges are learned in partial load operation. The reason for adapting the edge positions in the overrun mode is that the speed change does not appear as the smooth running almost reaches the value 0 in the overrun mode due to the inertial mass of the internal combustion engine. It is assumed that during such an operating state, the entire time intervals between equidistant edges have the same size. Therefore, the measured deviation can be used for the purpose of correcting the tolerance of edge positions.

By comparing the edge positions determined at the second time point with the actual edge positions learned at the first time point, effects occurring during the partial load operation are compensated for the rotational motion of the camshaft. Therefore, if the relationship learned during adaptation is applied to the measurement signal determined at the second time point, the actual angle value of the camshaft rotational motion can be smoothed. Thus, noise or leaps in the actual angle signal, caused by vibration torque in partial load operation, can be compensated.

Determining the relationship between the edge positions determined at the first time point and the actual angle of rotational motion of the crankshaft or camshaft determines the correction values that correlate the edge positions of the partial load operation and the edge positions of the full load operation. And determination of the relationship between the edge positions of the full load operation and the actual angle of rotational motion of the crankshaft or camshaft at the first time point (ie adaptation of the segment length of the partial load operation). In such a case, the correction values can be transferred to other internal combustion engines very preferably. This greatly simplifies the implementation of the present invention, since the effect of different vibration torques in partial load operation and full load operation is hardly influenced by manufacturing tolerances, but rather is purely an engine side effect. Therefore, variance of angular deviation between different internal combustion engines of the same model is not expected. Preferably, in this case, it is sufficient to apply the above adaptation to a special type of individual internal combustion engine at a first time point. The relationship learned in this adaptation can be used during the operation of all internal combustion engines of the same type. Therefore, it is not necessary to perform the above adaptation again for all of the individual internal combustion engines of the same type. Therefore, adaptation at the first time point can be carried out, for example, on a particular type of prototype or sample.

Preferably the edge positions corrected from the edge positions and correction values then measured at the second time of perception are determined in relation to the full load operation, and from the corrected edge positions in relation to the full load operation, the full load operation The actual angle value of the rotational motion of the camshaft can be determined on the basis of the relationship between the edge positions determined at and the actual angle of the rotational motion of the camshaft (at any point in time, especially in the range of regular segment length changes during operation). .

According to one preferred improvement, correction values are determined and used according to speed.

The correction values between the edge positions determined in full load operation during adaptation and the edge positions in full load operation and partial load operation can be stored as a reference value in the control device of the internal combustion engine, for example in a separate array.

Preferably, the first advancement point appears during the manufacturing process of the internal combustion engine, for example at the end of the manufacturing line. The second perception point preferably appears during operation of the internal combustion engine, for example in a vehicle or a commercial vehicle.

When the internal combustion engine is switched from full load operation during operation to a fuel saving mode in which all cylinders are no longer ignited, when determining the actual angle values of the camshaft rotational movement, the control is disadvantageous by the stored reference values that were determined during the manufacturing process. Leaps can be reduced. Preferably, the partial load operation is a half load operation in which half cylinders of the internal combustion engine are ignited. The present invention is also suitable for all other partial load operations where one or more of the cylinders is not operational. In one alternative preferred refinement of the invention, the shape of the individual cams of the camshaft can be changed during the lifting of the variable valve during partial load operation. Effects due to vibration torque caused by changing the shape of an individual cam can be effectively compensated using the method of the present invention.

In this case, during adaptation in the manufacturing process, all possible partial load operations provided during the operation of the internal combustion engine can be measured in each adaptation. Especially in this case, the correction values of the edge positions of the individual partial load operation and full load operation are determined. The difference between the edge positions in full load operation and in partial load operation is therefore relatively easy, without the need to independently determine a relatively more complex determination of the relationship between the edge positions of both individual partial load operations and the actual angle of camshaft rotational motion. Only a decision is needed. Thus, more complex, the determination of the relationship between the edge positions and the actual angle of the camshaft rotational movement needs to be performed only once for the edge positions of the full load operation.

The computer unit according to the invention, eg a control device for a vehicle, is designed to carry out the method according to the invention, particularly programmatically.

It is also desirable to implement the method in the form of software, since the execution control device is also used for other purposes, which is particularly inexpensive when it has to be provided anyway. Suitable data carriers for providing computer programs are, in particular, diskettes, hard disks, flash memory, EEPROMs, CD-ROMs, DVDs, and the like. You can also download programs through a computer network (Internet, intranet, etc.).

Other advantages and improvements of the present invention refer to the detailed description and accompanying drawings.

Of course, within the scope of the present invention, the features mentioned above and described below can each be used in the above-described combinations, or may be used in other combinations or alone.

The present invention is schematically illustrated in the drawings with reference to embodiments, and is described below with reference to the drawings.

1 is a schematic view of an apparatus formed to implement one preferred embodiment of the method according to the invention.
2 is a schematic graph of measurement signals that can be detected in the scope of one preferred embodiment of the method according to the invention.

1 shows an apparatus formed to implement one preferred embodiment of the method according to the invention.

The sensor wheel 10 is connected to the camshaft 11 of the internal combustion engine. The camshaft 11 is connected to the crankshaft of the internal combustion engine by, for example, a toothed belt (not shown in FIG. 1). In this embodiment, four marking portions 12a, 12b, 12c and 12d are provided on the periphery or edge of the sensor wheel 10 (e.g., one marking portion per cylinder is provided, where segment length: 360 ° NW / cylinder) Number). The area between the front portion of the marking portion 12a and the front portion of the marking portion 12b is called a segment SA. Similarly, the area between the front part of the marking part 12b and the front part of the marking part 12c is called a segment SB, and the area between the front part of the marking part 12c and the front part of the marking part 12d is segmented. It is called (SC), and the area between the front part of the marking part 12d and the front part of the marking part 12a is called a segment SD.

The transducer is formed as a hall sensor 13. The hall sensor 13 is arranged near the edge of the sensor wheel 10 and is connected to the control device 15 of the internal combustion engine by a line 14.

The sensor wheel shown in FIG. 1 has four segments (SA, SB, SC and SD), and is particularly suitable for a four-cylinder internal combustion engine. Ideally, the distance between the front parts of the marking parts is the same, and the camshaft angle between the front parts is ideally 90 ° NW, respectively. The time elapsed while one segment passes through the transducer 13 ideally corresponds to a camshaft rotational motion equal to an actual angle value of 90 ° NW, and thus a crankshaft rotational motion equivalent to an actual angle value of 180 ° KW. Corresponds to

로서 표시되어 있다. 제어 장치(15)는 이 전압 펄스 신호[

]를 평가하여 전압 펄스 시퀀스[

] 형태의 측정 신호를 결정한다.During operation of the internal combustion engine, the sensor wheel 10 also rotates as the camshaft 11 rotates. The beginning and end of each edge generates positive or negative voltage pulses in the transducer 13. This voltage pulse signal in Figure 1

Is marked as. The control device 15 uses this voltage pulse signal [

Voltage pulse sequence []

] Determine the type of measurement signal.

) 형태의 측정 신호의 그래프가 개략적으로 도시되어 있다. 트랜스듀서(13)에 의해 측정된 전압 펄스 신호[

]의 전압 펄스들은 도 2에서 시간(t)의 함수로서 펄스(21 내지 28)로서 그려져 있다.2 shows a voltage pulse sequence that can be detected in the scope of the preferred embodiment of the method according to the invention (

) A graph of the measurement signal in the form is schematically shown. Voltage pulse signal measured by the transducer 13 [

The voltage pulses of] are plotted in FIG. 2 as pulses 21 to 28 as a function of time t.

The first pulse 21 represents a time point or an actual angle value at which the front portion of the marking portion 12a passes through the transducer. Therefore, the pulse 21 represents the edge position of the first marking portion 12a. Similarly, the second pulse 22 indicates the front portion of the marking portion 12b and the edge positions of the second marking portion 12b. The third pulse 23 indicates the front portion of the marking portion 12c and the edge positions of the third marking portion 12c. The fourth pulse 24 indicates the front portion of the marking portion 12d and the edge positions of the fourth marking portion 12d. The pulse 25 again represents the front part of the marking portion 12a, indicating a complete one revolution of the camshaft 11, that is, the actual angle of 720 ° KW, and a complete one combustion cycle of the internal combustion engine, which is the symbol "SA ( t + 1) ”and reference numeral U1. The same applies for pulses 26, 27 and 28 and the symbols "SB (t + 1)", "SC (t + 1)" and "SD (t + 1)". The pulse 29 represents the complete two revolutions of the camshaft indicated by reference numeral U2.

) 형태의 측정 신호를 이용하여, 본 발명에 따른 방법의 한 바람직한 실시예가 수행될 수 있다.Voltage pulse sequence according to FIG. 2 (

) Using a measurement signal in the form, one preferred embodiment of the method according to the invention can be carried out.

)들이 등거리를 갖지 않는다. 예를 들어, 펄스(21)와 펄스(22) 사이의 시간 간격이 펄스(22)와 펄스(23) 사이의 시간 간격보다 작을 수도 있다.Due to the vibration torque generated during partial load operation, the time intervals between pulses 21, 22, 23 and 24 of one revolution of the camshaft at constant speed and the crankshaft angle (

) Are not equidistant. For example, the time interval between pulse 21 and pulse 22 may be smaller than the time interval between pulse 22 and pulse 23.

At the first advancing point, the edge positions during partial load operation are determined according to the actual angular value of the rotational movement of the crankshaft. For example, in this case, values of 0.5 ° KW, 176 ° KW, 359.8 ° KW, and 535.8 ° KW may appear. At this time, it is assumed that only the cylinders related to the segments SA and SC are in a half-load operation mode. Here, it can be seen that the edge positions of the segments SB and SD are advanced due to rotational non-uniformity of the camshaft (eg, oBdA). However, through adaptation, the values are treated as structural non-uniformities of the sensor wheel (edge positions assumed at 0.25 ° NW, 88 ° NW, 179.9 ° NW and 267.9 ° NW; actual structural conditions of the wheel as a result of adaptation at full load operation) These will be derived, for example, from 0.25 ° NW, 90.2 ° NW, 179.9 ° NW and 270 ° NW), the cam determined using this relationship from the measurement signal when the internal combustion engine is in the semi-load operating mode at the second perception point The actual angular value of the axis does not correspond to the actual camshaft angle for segment boundaries at both points, but is more suitable for subsequent processing and use, because the angle jumps (in this embodiment they would be about 2 ° NW) Because it is prevented. As already mentioned, the reason why the actual camshaft angle at these points is not important is that these cylinders do not ignite anyway.

Preferably, the correction values at the first time point are calculated as the angular deviation between the edge positions of the partial load operation and the edge positions of the full load operation and stored in the control device 15. These correction values are 0 ° NW, -2.2 ° NW, 0 ° NW and -2.1 ° NW in this example. At the second perception point, these correction values can be used to determine the actual angular value of the partial load operation together with the existing relationship for full load operation.

Claims (12)

A method for determining the actual angular value of the rotational motion of the camshaft 11 that rotates when the internal combustion engine is in the partial load operating mode, the method comprising:
-A sensor wheel (10) comprising a plurality of marking parts (12a, 12b, 12c and 12d), a rotating camshaft (11) and a sensor wheel (10) that is rotatably connected to,
-It is performed using a transducer 13 that detects the marking parts 12a, 12b, 12c and 12d of the sensor wheel 10 to determine the measurement signal 20,
-Edge positions 21-28 of the marking parts 12a, 12b, 12c and 12d of the sensor wheel 10 are determined based on the measurement signal 20,
At this time, at the second perception point,
-The measurement signal 20 is determined,
-Edge positions 21-28 at the second perception point are determined based on this measurement signal,
The rotational movement of the edge positions 21-28 and the camshaft 11 of the internal combustion engine, determined from the partial positions at the first advancing time, from the edge positions 21-28 at the second perception point. Based on the relationship between the actual angle, the actual angle value of the rotational motion of the camshaft 11 is determined,
The relationship between the edge positions 21-28 at the first advancing point and the actual angle of rotational motion of the camshaft 11 in partial load operation is determined,
The determination of the relationship at the time of the first advance,
Determination of correction values from edge positions 21-28 at the first advance point in partial load operation and edge positions 21-28 determined in full load operation,
-Determination of the relationship between the determined edge positions (21-28) during full load operation and the actual angle of rotational motion of the camshaft (11),
Determination of the actual angle value of the rotation of the crankshaft of the internal combustion engine at the second perception point,
Determination of edge positions relative to full load operation, corrected based on edge positions 21-28 and correction values at the second perception point,
-From the edge positions corrected with respect to the full-load operation, based on the relationship between the edge positions (21-28) determined during full-load operation and the actual angle of the rotational motion of the camshaft (11). A method for determining an actual angular value of a rotational motion of a camshaft that rotates when the internal combustion engine is in a partial load operating mode, comprising determining the actual angular value. delete delete The camshaft according to claim 1, wherein deviations between the edge positions (21-28) at the first advancing point in partial load operation and the edge positions (21-28) determined in full load operation are determined as a correction value. How to determine the actual angular value of a rotational motion. The method for determining the actual angle value of the camshaft rotational motion according to claim 1 or 4, wherein the first advancement point appears during the manufacturing process of the internal combustion engine. The method for determining the actual angle value of the camshaft rotational motion according to claim 1 or 4, wherein the second perception point appears during operation of the internal combustion engine. The method according to claim 1 or 4,
-The relationship between the actual angle of the rotational motion of the camshaft 11 of the first internal combustion engine of any type and the edge positions 21-28 is determined,
At the second point of perception,
-A method for determining the actual angle value of the camshaft rotational motion in which the actual angle value of the camshaft 11 rotation of the second internal combustion engine of the same type is determined based on the relationship determined for the first internal combustion engine. The method according to claim 1 or 4, wherein the shape of one or more cams of the camshaft (11) changes during partial load operation. The method according to claim 1 or 4, wherein the partial load operation is a half load operation. 5. The method according to claim 1 or 4, wherein a voltage signal is determined as the measurement signal (20). A computer unit (15) executing the method according to claim 1 or 4. A machine-readable storage medium storing a computer program comprising program code means, when the program code means are executed in the computer unit (15), causing the computer unit (15) to execute the method according to claim 1 or 4.

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