EP3017154B1 - Camshaft arrangement of a reciprocating piston internal combustion engine and a reciprocating piston internal combustion engine having such a camshaft arrangement - Google Patents

Description

The invention relates to a camshaft arrangement of a reciprocating internal combustion engine having at least one phase-adjustable inlet camshaft and at least one phase-adjustable exhaust camshaft and a reciprocating internal combustion engine with such a camshaft arrangement.

Out DE 195 27 503 A1 It is known to determine the angular position of crankshaft and camshaft with reciprocating internal combustion engines by means of suitable sensor systems. In this regard, reference is made in particular to the arrangement of encoder wheels with associated sensors.
DE 195 27 503 A1 does not refer to reciprocating internal combustion engines with two camshafts, in particular not on reciprocating internal combustion engines with two phase-adjustable camshafts.

Out DE 10 2008 032 026 Al a camshaft sensor unit for determining the absolute position of a camshaft of a reciprocating internal combustion engine with a transmitter wheel is known. The sender wheel has a number of triggers distributed over its circumference, which allows an angle recognition accuracy of less than 20 ° NW (degree camshaft).
DE 20 2008 032 026 A1 does not refer to reciprocating internal combustion engines with two phase-variable camshafts.

Out DE 101 56 780 A1 is a reciprocating internal combustion engine with an intake camshaft and an exhaust camshaft known, with only the exhaust camshaft is designed to be phase-adjustable and this is associated with a so-called Schnellstartgeberrad. DE 101 56 780 A1 does not refer to reciprocating internal combustion engines with two phase-variable camshafts.

The invention is based on the object, a camshaft arrangement for a reciprocating internal combustion engine having at least one phase-adjustable inlet camshaft and at least one phase-adjustable exhaust camshaft and a reciprocating internal combustion engine be provided with such a camshaft assembly that ensure a quick start capability of the reciprocating internal combustion engine, are inexpensive to implement and at the same time allow increased accuracy in the position detection of the camshaft.

The object is achieved according to the invention with the features of the independent claims.

In a camshaft assembly according to the invention for a reciprocating internal combustion engine with at least one phase-adjustable intake camshaft and at least one phase-adjustable exhaust camshaft of at least one phase-adjustable exhaust camshaft is assigned a Schnellstartgeberrad unit and the at least one phase-variable intake camshaft assigned a Präzisionsgeberrad unit, said Precision encoder wheel unit has a higher resolution than the Schnellstartgeberrad unit.

Under a Schnellstartgeberrad unit is understood in this context, a unit that generates a waveform that allows in conjunction with the waveform of a crankshaft sensor unit a unique assignment of the power stroke of each cylinder of the reciprocating internal combustion engine. In particular, in the case of a four-cylinder engine, this may be done by the combination of the signals of the quick start gear unit and the crankshaft sensor unit (e.g., detection of a sensor passing edge or other mark) being unique. For details, reference will be made in detail in connection with the embodiment.

In this context, a quick-starting-gear unit is understood as meaning, in particular, the combination of a quick-starting-sensor wheel comprising n ₁ segments with a fast-starting-sensor wheel sensor cooperating therewith, which is designed to reduce the starting time of a reciprocating internal combustion engine by providing reliable information during the starting process of a reciprocating internal combustion engine provides to the position of the exhaust valves. Such Schnellstartgeberrad units are known from the prior art. The invention assumes that the phasers of the intake camshaft and the exhaust camshaft are locked in unique reference positions at the start of the reciprocating internal combustion engine in a known manner, so that not only the position of the exhaust Camshaft, but also the position of the intake camshaft is known.

Under a Präzisionsgeberrad unit is presently understood in particular the combination of a Präzisionsgeberrades with n ₂ segments and a cooperating with this Präzisionsgeberrad sensor which has a higher resolution than the Schnellstartgeberrad unit and is designed to provide additional information regarding the operation of a reciprocating internal combustion engine To provide the degree of filling of individual cylinders by accurately determining the closing timing of the intake valves via the intake camshaft position. This is done by the permanent signal evaluation of Präzisionsgeberrades means of Präzisionsgeberrad sensor, in particular during operation of the reciprocating internal combustion engine. By "higher resolution" is meant here that the number of segments of the Präzisionsgeberrades is greater than the corresponding number of Schnellstartgeberrades. One revolution of the intake camshaft is therefore "resolved higher" by means of the precision gear unit, ie divided into smaller sections than with the quick start gear unit.

It should also be noted that the quick start gear unit and the precision gear unit are used for different purposes, namely the quick start gear unit for detecting the position of the crank and timing gear of a reciprocating internal combustion engine during startup with locked camshaft timers on the one hand and the precision gear wheel On the other hand, unit for improving charge detection during operation of the reciprocating internal combustion engine. The precision encoder wheel is therefore preferably divided into a plurality of equally sized segments of uniform segment pitch (the only exception is often a reference mark with omission or doubling of a segment), while the quick-start gear wheel comprises fewer segments and often has uneven segment pitch. The Quick Start Transmitter Unit additionally provides position sensing of the exhaust camshaft during engine operation, but with less accuracy than the Precision Transducer Unit.

A camshaft assembly according to the invention has the advantage that by assigning an arrangement of a Präzisionsgeberrad unit to a phase-variable intake camshaft and assigning a Schnellstartgeberrad unit to a phase-variable exhaust camshaft, a high accuracy of the position detection of the intake camshaft with simultaneous quick start capability is enabled and thereby In a variety of operating conditions a more precise and thus more efficient injection and combustion in a reciprocating internal combustion engine is made possible. The invention therefore represents Reciprocating internal combustion engines with dual phasing (ie, with phase-variable intake camshaft and phased-out exhaust camshaft) is a preferred compromise of manufacturing cost and accuracy in terms of charge detection of reciprocating internal combustion engines.

The term segment in the present case means any means for generating and detecting at least two different signals that allows a position evaluation. Such means are, in particular, geometrically recognizable elements (such as flanks with raised and recessed areas therebetween, teeth, gaps, slots), magnetic fields and / or optical marks that can be detected by known sensors. Preferably, segments and sensors are used which can be distinguished between exactly two different states or signals (e.g., high / low or 0/1).

In a practical embodiment of a camshaft assembly according to the invention each segment of the Schnellstartgeberrades and / or Präzisionsgeberrades of a raised area e and a recessed area v, wherein the raised areas e and the recessed areas v are connected to each other via radially extending flanks F. By "radially extending" is not necessarily meant an exclusively radial extension direction. Extending directions of flanks F, which extend partly in the radial direction and partly in the circumferential direction, should also be encompassed by this formulation. In the latter case, they can be differentiated from the raised areas e and the recessed areas v, in particular when the raised areas e and the recessed areas v extend exclusively in the circumferential direction.

In a further practical embodiment of a camshaft arrangement according to the invention, all elevated regions e and / or all recessed regions v of a quick-start transmitter wheel and / or a precision encoder wheel are each arranged on a circle arranged concentrically about the axis of rotation D of the respective camshaft. This has the advantage that a sensor directed in the radial direction onto the quick-starting gear wheel and / or the precision encoder wheel has to detect in each case a constant distance in raised areas e described above and in recessed area v as described above. It is therefore easy to use and inexpensive sensors available.

It is further preferred in a camshaft arrangement according to the invention if the number of segments n _{1 of} the precision encoder wheel is at least (2 * n ₂ -1). Preferably, the number of segments n _{1 is} either (x * n ₂ ), (x * n ₂ +1) or (x * n ₂ -1), where x is a positive integer and n _{2 is} the number of segments of the quick-start wheel is.

The value (x * n ₂ +1) results when a segment of the "standard size" is subdivided into two segments of half size as mark of a complete revolution for the precision gear wheel, ie if the marking is realized by an additional raised area e ,

The value (x * n ₂ -1) results when a higher range e is omitted as the marking of a complete revolution for the precision gear wheel (gap as marking). A gap as a mark is particularly preferred if the proposed Präzisionsgeberrad sensor could not trigger an additional mark or not reliable, ie, if the existing markers already the resolution of the intended Präzisionsgeberrad sensor is fully or largely exhausted.

The value (x * n ₂ ) results when an additional mark independent of the segments is made on the precision encoder wheel. An additional marking is particularly preferred if it can be reliably detected by the intended Präzisionsgeberrad sensor.

In order to keep the manufacturing costs of a Präzisionsgeberrades and thus the cost of a camshaft assembly according to the invention low, it may be advantageous if the Präzisionsgeberrad has a larger outer diameter than the Schnellstartgeberrad. In this case, the higher resolution (i.e., more segmented) precision encoder wheel can be made with larger absolute tolerances because the length of the raised and recessed areas (which are usually circular arc sections) become longer as the diameter increases.

The invention also relates to a reciprocating internal combustion engine with a camshaft arrangement as described above. The advantages associated therewith, which have already been described above in connection with the camshaft arrangement, are hereby once again referred to. The term reciprocating internal combustion engine specifically refers to four-stroke gasoline engines of motor vehicles. However, the invention is not limited thereto, but can also be used in particular for other vehicles, such as for marine or aircraft engines, as well as for stationary engines.

In a further practical embodiment of a reciprocating internal combustion engine according to the invention, the latter has z cylinders, the number n _{2 of} the segments of the quick-starting sensor wheel (12) corresponding to an integer multiple of the number z of the cylinders. Integer multiples designate in particular a number of segments n ₂ corresponding exactly to the number z of the cylinders. As a result, each individual cylinder of the reciprocating internal combustion engine is assigned the same number of evaluable signals in the charge cycle or power stroke.

It is further preferred if a reciprocating internal combustion engine according to the invention comprises a crankshaft, which is associated with its own crankshaft-Geberrad unit. Such a crankshaft-donor wheel unit is preferably a donor wheel with a plurality of teeth, lugs and / or slots, which are distributed uniformly over the circumference, wherein the resolution, the higher the number of teeth, lugs and / or Slots are arranged distributed over the circumference. By combining the signals detected by the crankshaft sensor wheel unit with the signals detected by the quick-start sensor wheel unit, the position of the crank and timing drive of the reciprocating internal combustion engine (with locked camshaft actuators) can be uniquely determined. This is possible with a lower accuracy as well by a combination of the signals of the quick-start transmitter wheel unit with the Präzisionsgeberrad unit (for example, for emergency).

Preferably, the crankshaft, the at least one intake camshaft and the at least one exhaust camshaft of a reciprocating internal combustion engine according to the invention are interconnected via a common control drive and are driven together. This saves separate drive units and a synchronization of these drive units.

Fig. 1

eine Schnellstartgeberrad-Einheit und eine Präzisionsgeberrad-Einheit einer erfindungsgemäßen Nockenwellenanordnung zusammen mit einer Präzisionsgeberrad-Einheit einer Kurbelwelle.

Further practical embodiments and advantages of the invention are described below in conjunction with the drawings. It shows:

Fig. 1

a Schnellstartgeberrad unit and a Präzisionsgeberrad unit of a camshaft assembly according to the invention together with a Präzisionsgeberrad unit of a crankshaft.

FIG. 1 shows a schematic view of a rotation axis D _{K of} a crankshaft, not shown, a rotation axis D _{A of} an exhaust camshaft, not shown, and a rotation axis D _{E of} an unillustrated intake camshaft of a series four-cylinder internal combustion engine (gasoline engine).

The exhaust camshaft is coupled to a quick start gear unit 10 that includes a quick start gear wheel 12 and a quick start gear sensor 14. The Schnellstartgeberrad 12 includes four mutually arranged elevated areas e and recessed areas v, which are connected to each other via exclusively in the radial direction extending flanks F. The raised areas may also be referred to as "teeth." By "coupled" is meant here that the Schnellstartgeberrad 12 is rotatably connected to the exhaust camshaft. This can be done in particular by integral formation of a Schnellstartgeberrades 12 with the camshaft or by rotationally fixed connection of a separate Schnellstartgeberrades 12 (as in FIG. 1 shown) with the camshaft. About the Schnellstartgeberrad sensor 14 is determined whether in the measuring range of the Schnellstartgeberrad sensor 14 is just a raised area e and / or a recessed area v. From this, current positions of the exhaust valves are derived. As in FIG. 1 can be seen, the Schnellstartgeberrad 12 four segments with nonuniform segment division, ie, the angular range of a recessed area v and the angular range of a raised portion e of a segment are of different sizes.

The intake camshaft is coupled to a precision encoder wheel assembly 20 that includes a precision encoder wheel 22 and a precision encoder wheel sensor 24. The Präzisionsgeberrad 22 includes 12 + 1 (= 13) alternately arranged areas e and recessed areas v, which are connected to each other over themselves exclusively in the radial direction extending flanks F. By "counting" and evaluating the signals using the Präzisionsgeberrad sensor 24, the current position of the intake camshaft can be limited. The evaluation can be done, for example, in a known manner by measuring the magnetic flux density over the rotation angle of the intake camshaft. The evaluation is used to determine the degree of filling of the reciprocating internal combustion engine. The elevated area e, which in FIG. 1 is directed to the Präzisionsgeberrad sensor 24 and is part of an additional segment, serves as a reference mark. The Präzisionsgeberrad 22 thus has twelve segments with a uniform (simple) division, whereby a segment with a simple division was "divided" into two segments with half pitch by the reference mark described above.

The crankshaft is coupled to a crankshaft donor wheel unit 30 that includes a crankshaft donor wheel 32 and a crankshaft donor wheel sensor 34. The crankshaft phaser wheel 32 includes a plurality of uniformly circumferentially distributed teeth 36 and a tooth space 38 that serves as a reference mark.

In the exemplary embodiment shown, the sensors 14, 24, 34 are known Hall sensors. It is the person skilled in the art to use other suitable sensors instead of these sensors 14, 24, 34, and in particular if the segments are deviated instead of increased area e and recessed areas v (eg magnetic and / or optical segments and corresponding sensors). ,

• d_e1: Durchmesser im Bereich der erhöhten Bereiche e des Präzisionsgeberrades 22
• d_v1: Durchmesser im Bereich der vertieften Bereiche v des Präzisionsgeberrades 22
• d_e2: Durchmesser im Bereich der erhöhten Bereiche e des Schnellstartgeberrades 12
• d_v2: Durchmesser im Bereich der vertieften Bereiche v des Schnellstartgeberrades 12

In FIG. 1 the following dimensions are included:

• d _e1 : diameter in the region of the raised regions e of the precision encoder wheel 22
• d _v1 : diameter in the region of the recessed areas v of the Präzisionsgeberrades 22nd
• d _e2 : diameter in the region of the raised regions e of the quick-start sensor wheel 12
• d _v2 : diameter in the region of the recessed areas v of the quick-starting wheel 12

In the embodiment shown, the following dimensions were used: d _e1 = 80 mm, d _v1 = 72 mm, d _e2 = 60 mm. The dimension d _v2 can be suitably adapted to the accuracy of the quick start sensor 14. In the embodiment shown, d _{v2 is} approximately 50 mm. It is advantageous in an inventive arrangement, if d _{e1 is selected to be} larger than d _e2 , since the resolution of the Präzisionsgeberrades 22 is higher and the required tolerances may be greater, the greater d _{ei1 is} selected.

In the FIG. 1 At the Präzisionsgeberrad 22 registered angle α, β and γ are in the illustrated embodiment α = 25.5 ° (total 11 times), β = 10.5 ° (a total of 2 times) and γ = 4.5 ° (a total of 13 Sometimes present, ie at each elevated section). The circumference of the Präzisionsgeberrades 22 is thus divided into 11 segments with an angle of 30 ° and 2 segments at an angle of 15 °.

The features of the invention disclosed in the present description, in the drawings and in the claims may be essential both individually and in any desired combinations for the realization of the invention in its various embodiments. The invention is not limited to the described embodiments. It can be varied within the scope of the claims and taking into account the knowledge of the person skilled in the art.

LIST OF REFERENCE NUMBERS

10

Schnellstartgeberrad unit

12

Schnellstartgeberrad

14

Schnellstartgeberrad sensor

20

Präzisionsgeberrad unit

22

Präzisionsgeberrad

24

Präzisionsgeberrad sensor

30

Crankshaft sensor wheel unit

32

Crankshaft sensor wheel

34

Crankshaft sensor wheel sensor

36

tooth

38

gap

Claims (10)

1. Camshaft arrangement for a reciprocating piston internal combustion engine having at least one phase-adjustable inlet camshaft and at least one phase-adjustable outlet camshaft,
   characterized
   in that the at least one phase-adjustable outlet camshaft is assigned a quick-start encoder wheel unit (10), and the at least one phase-adjustable inlet camshaft is assigned a precision encoder wheel unit (20), wherein the precision encoder wheel unit (20) has a higher resolution than the quick-start encoder wheel unit (10).
2. Camshaft arrangement according to the preceding claim, characterized in that the quick-start encoder wheel unit (10) comprises a quick-start encoder wheel (12) with n₂ segments and a quick-start encoder wheel sensor (14) which interacts with the quick-start encoder wheel (12), and the precision encoder wheel unit (20) comprises a precision encoder wheel (22) with n₁ segments and the precision encoder wheel sensor (24) which interacts with the precision encoder wheel (22).
3. Camshaft arrangement according to Claim 2, characterized in that each segment of the quick-start encoder wheel (12) and/or of the precision encoder wheel (22) is composed of an elevated region e and a countersunk region v, wherein the elevated regions e and the countersunk regions v are connected to one another via radially extending edges F.
4. Camshaft arrangement according to Claim 3, characterized in that all the elevated regions e and/or all the countersunk regions v of the quick-start encoder wheel (12) and/or of the precision encoder wheel (22) are each arranged on a circle which is arranged concentrically about the rotational axis D of the respective camshaft.
5. Camshaft arrangement according to one of Claims 2 to 4, characterized in that the number of segments n₁ of the precision encoder wheel (22) is at least (2*n₂-1).
6. Camshaft arrangement according to one of Claims 2 to 5, characterized in that the precision encoder wheel (22) has a larger external diameter than the quick-start encoder wheel (12).
7. Reciprocating piston internal combustion engine comprising a camshaft arrangement according to one of the preceding claims.
8. Reciprocating piston internal combustion engine according to Claim 7 with z cylinders, characterized in that the number n₂ of segments of the quick-start encoder wheel (12) corresponds to an integral multiple of the number z of cylinders.
9. Reciprocating piston internal combustion engine according to Claim 7 or 8, characterized by a camshaft to which a separate crankshaft encoder wheel unit (30) is assigned.
10. Reciprocating piston internal combustion engine according to one of Claims 7 to 9, characterized in that the crankshaft, the at least one inlet camshaft and the at least one outlet camshaft are connected and driven via a common control drive.

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