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    • 专利摘要:
    The invention relates to a camshaft gear (1), forming a target for a camshaft position sensor, the gear comprising a circular body comprising two opposite main faces, and at least six teeth distributed over the circumference of the circular body, each tooth comprising two edges, one corresponding to a rising front and the other to a falling front, according to a direction of rotation of the wheel, the toothed wheel having an asymmetry of revolution, characterized in that the six teeth are shaped so that the toothed wheel includes, considering the same main face (11 A) and the same direction of rotation of the wheel: - four fronts (14) of the same first rising type or descending spaced respectively by 90 °, and - six fronts (15) of the same second type respectively descending or rising, spaced respectively by 60 °.
    公开号:FR3088718A1
    申请号:FR1871563
    申请日:2018-11-16
    公开日:2020-05-22
    发明作者:Fabien JOSEPH；Stephane Eloy
    申请人:Continental Automotive GmbH；Continental Automotive France SAS；
    IPC主号:
    专利说明:

    Description
    Title: Reversible target for 3, 4 or 6 cylinder engine
    Technical Field [0001] The invention relates to a camshaft gear wheel forming a target for a camshaft position sensor, suitable for three, four or six cylinder engines. The wheel is particularly suitable for use with a position sensor of the type capable of detecting a high or low level of the toothed wheel and of detecting, from a level variation, a type of rising or falling edge of a wheel tooth.
    STATE OF THE ART In the operating cycle of an internal combustion engine, it is necessary to know precisely the position of the crankshaft in order to be able to synchronize different actions such as fuel injection, piloting of the spark plugs. ignition, management of distribution devices, etc. This optimizes combustion efficiency and reduces fuel consumption and harmful emissions.
    To do this, a crankshaft conventionally comprises a toothed wheel whose teeth are detected by a sensor. The toothed wheel typically comprises a set of teeth distributed regularly along its circumference, with the exception of a reference portion devoid of teeth, also called gap. By detecting the passage of the teeth in front of the sensor and by counting the number of teeth passed from the gap, it is possible to know the position of the crankshaft on a 360 ° turn.
    However, an engine cycle corresponds to two complete rotations of the crankshaft, and it is therefore insufficient to determine the position of the engine only from the crankshaft wheel.
    This information is therefore combined with information on the angular position of the camshaft, which is rotated by the crankshaft and also includes a toothed wheel whose teeth are detected by a corresponding sensor.
    While an engine cycle corresponds to two 360 ° rotations of the crankshaft, it only corresponds to a 360 ° rotation of the camshaft. Consequently, the gear of the camshaft exhibits an asymmetry of rotation which, crossed with the information on the position of the crankshaft, makes it possible to deduce with precision the state of the engine cycle.
    Thus, each time the engine is started, the engine is synchronized when the crankshaft gap is detected, combined with the detection of the state of the camshaft wheel.
    Referring to [Fig. 1], in the case of a variable timing engine (also called Variable Valve Timing or VVT), provision may be made to offset the angular position of the intake camshaft and / or the camshaft d exhaust relative to the crankshaft to cause recirculation of exhaust gases in the cylinders to reduce fuel consumption and emissions.
    In [Fig. 1], there is shown on the abscissa the angular position of the crankshaft in degrees (an angle of rotation of the crankshaft corresponding to twice the corresponding rotation of the camshaft), and on the ordinate the displacement of the intake valves or exhaust in millimeters. The displacement of the intake (curve A) and exhaust (curve B) valves controlled by the intake and exhaust camshafts by default is shown in solid lines, and in dashed lines the offset of the angular position of the camshafts (curve A 'for the intake valves and B' for the exhaust valves) to allow the existence of a range of overlap between the opening phases of the intake valves and d 'exhaust.
    It is important that the design of a camshaft gear wheel takes this possible offset into account so that good synchronization with the information coming from the crankshaft gear is possible despite this possible offset.
    To improve the synchronization performance and the control of the variable distribution, it is known to position teeth on the toothed wheel of the camshaft forming marks specific to each cylinder. For example, a camshaft gear of a four-cylinder engine may have four fronts each spaced 90 °, the crossing of the sensor by each front corresponding to the same position of the piston in each respective cylinder.
    However, several engines, having a different number of cylinders, are used by the same manufacturer on the different vehicles in its range. This results in a great variety of cogwheels of camshafts to be managed, which increases the production cost of these wheels.
    In addition, it should be noted that there are two types of camshaft position sensors, and two types of corresponding toothed wheels.
    A first type, called a differential sensor, does not always make it possible to detect the first high level (corresponding to a tooth on the wheel) or the first low level (corresponding to an interval between two teeth). Depending on the initialization level of the sensor. It will only be able to detect levels when the first front causing it to change states has been seen.
    In this case, the targets used have a possibly large number of teeth to understand at least as many teeth as there are relevant fronts to detect, all the teeth having the same reduced size (the targets are also called targets to pawns), in order to be able to always detect a rising or falling edge on each tooth (the retained edge will be the one which causes the initialization level of the sensor to exit). In this case, the computer connected to the sensor detects only one edge per tooth, always of the same rising or falling type. It is the number and spacing of the teeth that makes a gear specific to a three- or four-cylinder engine.
    Document US2014 / 360254 discloses a camshaft toothed wheel which is adapted to be used in conjunction with a differential sensor, and comprises at least one tooth at each of the following positions of its circumference: 0 °, 60 ° , 90 °, 120 °, 180 °, 240 °, 270 ° and 300 °. Each tooth has a front detectable by a sensor.
    This allows to obtain a single wheel which is compatible both with four-cylinder engines (since the information corresponding to each cylinder is provided by the teeth 0 °, 90 °, 180 ° and 270 °) and with three and six cylinder engines (information provided by teeth 0 ° CAM, 60 ° CAM,
    120 ° CAM, 180 ° CAM, 240 ° CAM, 300 ° CAM).
    A second type of sensor, called TPO sensor, from the English acronym for "True Power On", is suitable for detecting a high or low level of a toothed wheel as soon as it is initialized, which makes it possible to deduce the crossing from a forehead. These sensors have higher accuracy for detecting one type of edge, usually falling edges, but lower accuracy for detecting the other type of edge.
    The targets used for this type of sensor generally have fewer teeth than the targets used for the differential sensors since the high and low levels of the toothed wheel must be long enough to be able to be detected by the sensor, and moreover the Rising and falling edges can be detected by the sensor. On the other hand, the teeth are of variable lengths and generally greater than the length of a target tooth for a differential sensor. These targets are also called "level targets".
    The document described above is not suitable for use with a TPO type sensor.
    SUMMARY OF THE INVENTION In view of the above, an object of the invention is to propose a toothed wheel of camshafts which is compatible with engines comprising three, four or six cylinders, and which can be used with a TPO type sensor capable of detecting a high or low level of a toothed wheel.
    An object of the invention is also to provide a toothed wheel allowing synchronization performance as good, whether the engine comprises three, four, or six cylinders.
    Another object of the invention is to provide a camshaft gear which is compatible with a variable timing motor.
    In this regard, the invention relates to a camshaft gear, forming a target for a camshaft position sensor, the gear comprising a circular body comprising two opposite main faces, and at least six teeth distributed over the circumference of the circular body, each tooth comprising two edges, one corresponding to a rising front and the other to a falling front, according to a direction of rotation of the wheel, the toothed wheel having asymmetry of revolution, characterized in that the six teeth are shaped so that the toothed wheel comprises, considering the same main face and the same direction of rotation of the wheel:
    - four fronts of the same first type rising or falling, spaced 90 ° apart respectively, and
    - six fronts of the same second type, respectively falling or rising, spaced 60 ° apart respectively.
    Advantageously, but optionally, the toothed wheel comprises a marking element on one of the two opposite main faces.
    Advantageously, but optionally, the toothed wheel has on its circumference at least two zones devoid of fronts at an angle of at least 35 °, the two zones being spaced by 180 °. For example, the toothed wheel may have on its circumference four zones devoid of one of the four fronts spaced 90 ° and devoid of one of the six fronts spaced 60 °, the four zones being spaced 90 °.
    In one embodiment, the gear wheel has six teeth, two teeth each of which include one of the six fronts spaced 60 ° and a front of the same type as the four fronts spaced 90 °, but separate from those -ci, said respectively first and second edges not allocated, and, noting:
    - At the minimum angular distance between one of the four fronts spaced by 90 ° and one of the six fronts spaced by 60 °,
    - B the minimum angular difference between one of the six fronts spaced 60 ° and the first unallocated front, and
    - C the minimum angular difference between one of the six fronts spaced 60 ° and the second unassigned front, the angular positions of the edges of the teeth of the toothed wheel are [0, A, 60, 90 + A, 120, 180-C, 180, 180 + A, 240, 270 + A, 300, 360B], [0028] Each tooth corresponds to a high level of the toothed wheel and each interval between two teeth corresponds to a low level of the toothed wheel , and the toothed wheel being adapted to form a target for a camshaft position sensor of the type capable of detecting a high or low level of the tooth and to deduce from a level variation the presence of a front of tooth, and, in one case, the minimum angular deviation A corresponds to a high level of the toothed wheel, and is defined by the following relationships:
    [Math. 1]
    A> tan- 1 ('Asüi.'j and 30 _ A > tan 1 where R is the radius of the toothed wheel including a height of the teeth relative to the circular body, r is the radius of the circular body, Lhaut is the distance minimum between the edges of a tooth allowing detection of the high level between the two edges by the sensor, and Lbas is the minimum distance between the edges of two consecutive teeth delimiting an interval allowing detection of the low level between these edges by the sensor .
    In this case, the angular deviations B and C correspond to a low level of the toothed wheel, and are defined by the following relationships:
    [Math. 2] r>. rr . „ T -ii ^ haut
    B> tan (- ^ -) and 60 - B> tan 1 1 ^ 1 and [Math. 3] v r J RJ with C and B having different values.
    Each tooth corresponds to a high level of the toothed wheel and each interval between two teeth corresponds to a low level of the toothed wheel, the toothed wheel being adapted to form a target for a camshaft position sensor of the type capable of detecting a high or low level of the tooth and to deduce from a level variation the presence of a tooth front, and, in another case, the minimum angular difference A corresponds to a low level of the gear wheel, and is defined by the following relationships:
    [Math. 4]
    A> and 30 - A>
    v r 7 R 7 where R is the radius of the toothed wheel including a height of the teeth relative to the circular body, r is the radius of the circular body, Lhaut is the minimum distance between the edges of a tooth allowing a detection of the high level between the two edges by the sensor, and Lbas is the minimum distance between the edges of two consecutive teeth delimiting an interval allowing detection of the low level between these edges by the sensor.
    In this case, the angular deviations B and C correspond to a high level of the toothed wheel, and are defined by the following relationships:
    [Math. 5] n , rr , r ,. _1 f b low
    B> tan 1 (—-—) and 60 - B> tan 1 - k 7 7 v) and [Math. 6] ~. . _ι, Λ & αΐίί . , n f b low
    C> tan i (----) and 60 - C> tan 1 --R r / with C and B having different values.
    The invention also relates to an internal combustion engine comprising three, four or six cylinders, comprising a camshaft, a toothed wheel according to the above description, mounted integral with the camshaft, in which each tooth corresponds to a high level of the toothed wheel and each interval between two teeth corresponds to a low level of the toothed wheel, and the internal combustion engine furthermore comprises a camshaft position sensor capable of detecting a level top or bottom of the tooth and to detect, from a level variation, a tooth front, the sensor having a greater detection performance for one type of front than for the other type of front, the toothed wheel being mounted on the camshaft so that a main face is oriented towards the camshaft position sensor, the main face oriented towards the position sensor being chosen so that:
    - if the engine has three or six cylinders, the six edges spaced by 60 ° are edges of the type for which the detection performance by the sensor is higher, and if the engine has four cylinders, the four edges spaced by 90 ° are fronts of the type for which the detection performance by the sensor is superior.
    The invention also relates to a method of assembling an internal combustion engine, comprising a camshaft, a toothed wheel according to the above description, and a camshaft position sensor of the type able to detect a high or low level of the toothed wheel and to detect, from a level variation, a tooth front, the sensor exhibiting a higher detection performance for one type of front than for the other type of front, the assembly process comprising mounting the toothed wheel on the camshaft so that a main face of the toothed wheel is oriented towards the camshaft position sensor, in which, if the engine has three or six cylinders, the main face facing the position sensor is chosen so that the six fronts spaced 60 ° are of the type for which the sensor has the best detection performance, and if the engine has four cylinders, the main face facing position sensor is the opposite side, so that the four fronts spaced 90 ° are of the type for which the sensor has the best detection performance.
    The toothed wheel according to the invention is compatible with six-cylinder engines, since it comprises six fronts regularly spaced 60 ° apart. Therefore it is also compatible with three-cylinder engines since among these six fronts it includes three fronts regularly spaced 120 °. Finally, it is compatible with four-cylinder engines because it includes four fronts regularly spaced 90 ° apart.
    In addition, the edges spaced by 60 ° are all of the same type, for example rising edge, and the edges spaced by 90 ° are all of the same other type, for example falling edge, which allows the gear wheel to present synchronization performance as good for the three types of engines, even with a camshaft position sensor having better detection for a particular type of front, because it is then possible to position the gear wheel relative to the sensor so that the edges to be detected by the sensor (edges spaced 60 ° or 90 ° depending on the type of motor) correspond to the type of edge best detected by the sensor.
    The constraint on the types of fronts offers the advantage of having a limited number of teeth (six teeth), which has the advantage of having a reduced target size (each tooth or hollow between the front teeth have a minimum size to be correctly detected by the sensor).
    There is therefore no need to design and produce different targets for three-cylinder engines, four-cylinder engines and six-cylinder engines.
    In addition, the presence of two symmetrical portions devoid of teeth and at least 35 ° of angular range ensures that even in case of phase shift of the camshaft for a variable distribution motor, the front used for VVT control is not in a gap area of the crankshaft wheel. In fact, the toothed wheel according to the invention can be used in a variable-distribution engine by positioning the portion devoid of teeth relative to the gap of the crankshaft wheel so that, even in the event of shifting of the camshaft, the gap of the crankshaft wheel always coincides with the portion without teeth. The engine position being based on the analysis of crankshaft fronts; the gap area generates greater inaccuracy.
    Brief description of the drawings [0040] Other characteristics, details and advantages of the invention will appear on reading the detailed description below, and on analysis of the appended drawings, in which:
    [Fig. 1], already described, represents the displacement of the intake and exhaust valves as a function of the angular position of the camshaft to which they are linked.
    [Fig. 2a] shows a face of an example of a camshaft gear wheel according to an embodiment of the invention.
    [Fig. 2b] represents the face opposite to that of [Fig. 2a] of the same example of a toothed wheel.
    [Fig. 3a] represents a face of another gear wheel geometry having the same angular positions of fronts as the gear wheel of [Fig. 2a] and [Fig. 2b], by reversing the types of fronts.
    [Fig. 3b] represents the face opposite to that of [Fig. 3a] of the same example of a toothed wheel.
    [Fig. 4] shows an example of synchronization of a toothed wheel according to [Fig. 2a] and [Fig. 2b] with a crankshaft gear.
    [Fig. 5] shows an example of a four-cylinder engine comprising a toothed wheel of camshafts according to an embodiment of the invention.
    Description of the embodiments In the following, we will note angles measured in degrees on, or relating to an angular position of a toothed wheel of camshafts in "° CAM", and angles measured in degrees on , or concerning an angular position of a crankshaft gear in "° CRK". A rotation of 1 ° CAM corresponds to a rotation of 2 ° CRK.
    Referring to the figures [Fig. 2a] and [Fig. 2b], we will now describe a gear 1 of camshafts, forming a target for a sensor 2 of the angular position of camshafts.
    The toothed wheel 1 has the general shape of a disc, that is to say that it comprises a circular body 10 having two opposite main faces 11A and 11B, these faces being circular, and the wheel comprises at the periphery of the circular body 10 a plurality of teeth 12. Each tooth is delimited by two edges 13 extending substantially radially and which successively form, when the wheel 1 passes in front of a sensor 2, a rising edge and a falling edge.
    The fact that an edge constitutes a rising edge or a falling edge depends on which side we stand to observe the toothed wheel, that is to say on the main face that we observe, as well as on the direction of rotation of the wheel.
    There is shown in the figures [Fig. 2a] and [Fig. 2b] an example of a toothed wheel 1 according to an embodiment of the invention, viewed respectively from one side and from the opposite side, that is to say by considering one and the other of the main faces 11A and 11 B, and an arrow also represents the direction of rotation of the wheel which makes it possible to define a tooth edge as being a rising edge or a falling edge.
    The toothed wheel 1 has alternately high and low levels, a high level corresponding to a tooth, and a low level corresponding to an interval between two consecutive teeth.
    The toothed wheel is intended to be mounted for rotation with a camshaft of an internal combustion engine. For its mounting on the camshaft, a circular and centered through-hole can possibly be made in the toothed wheel.
    The gear 1 is adapted to be used with a sensor 2 of TPO type (True Power On), or level sensor, that is to say a sensor adapted to always be able to detect the high and low levels of the toothed wheel, and for detecting from a level variation a rising or falling tooth front.
    For example, the sensor 2 may comprise a detection cell (for example of the Hall effect cell type, magneto-resistive cell, etc.) adapted to detect a high or low level of the toothed wheel, and an integrated computer suitable for detecting a front from a variation in the high or low level of the toothed wheel.
    Such a sensor most often has detection performance, that is to say typically an edge detection accuracy - better for one type of edge, often falling edges, than for the other type of forehead. An example of a level sensor can have an accuracy of 0.5 ° CAM on the detection of a falling edge and an accuracy of 1 ° CAM on the detection of a rising edge.
    The toothed wheel 1 advantageously comprises at least six teeth, for example exactly six teeth 12, spaced apart from intervals devoid of teeth.
    To be able to be used in conjunction with data obtained from a crankshaft toothed wheel, the toothed wheel 1 of camshafts advantageously has an asymmetry of revolution, such as the profile of the teeth of any toothed wheel half is different from that of the other half. Thus, a tooth detected by the sensor can be identified and deduced therefrom, together with data of the angular position of the crankshaft, the state of the engine cycle.
    In addition, the toothed wheel 1 is adapted to be able to be used in three-cylinder engines, four-cylinder engines, and six-cylinder engines, by presenting equally good synchronization performance for the three types of engines.
    To do this, the six teeth of the toothed wheel 1 are shaped so that, by placing themselves on the same side of the wheel - that is to say by considering the same main face 11A or 11B - and for the same direction of rotation of the wheel, the toothed wheel 1 has:
    - Four fronts 14 of the same first type, rising or falling, spaced 90 ° CAM, and
    - Six fronts 15 of the same second type, respectively falling or rising, spaced 60 ° CAM.
    The edges 14 spaced at 90 ° CAM form marks associated with respective cylinders of a four-cylinder engine to promote the control of the variable distribution (VVT) in this type of engine, and the edges 15 spaced 60 ° CAM form landmarks associated with the respective cylinders of a six-cylinder engine. In addition, these fronts spaced 60 ° apart comprise three fronts spaced 120 ° apart forming marks associated with the respective cylinders of a three-cylinder engine.
    In addition, the fact that the fronts 15 spaced 60 ° CAM are not of the same type as the fronts 14 spaced 90 ° CAM provides the same synchronization performance for a four-cylinder engine and an engine of three or six cylinders.
    Indeed, if the position sensor 2 of the engine has better detection performance for a particular type of front, for example falling edges, the target can be positioned by putting a main face 11 or the other in look of the sensor, so that the edges of the type best detected by the sensor correspond to the edges forming the mark of the cylinders for the type of engine considered.
    In other words, the target is mounted in one direction on a three or six cylinder engine (for example face 11B in the figures [Fig. 2b] and [Fig. 3b]), and in the other direction (for example face 11A in the figures [Fig. 2a] and [Fig. 3a]) on a 4-cylinder engine, if it is assumed that the sensor is configured in the same way.
    In the figures [Fig. 2a] and [Fig. 2b], there is thus shown an example of a toothed wheel 1 viewed respectively from one side and the other, for the same direction of rotation of the wheel.
    In [Fig. 2a], the four edges 14 spaced 90 ° CAM are rising edges. Turning the wheel over, in [Fig. 2b], the six edges 15 spaced 60 ° CAM are also rising edges. There is thus a reversible wheel.
    Indeed, if the position sensor 2 has better detection accuracy for the falling edges, the target is positioned so that the main face 11B shown in [Fig. 2b] or opposite the position sensor 2 for a four-cylinder engine (because the four fronts 14 spaced 90 ° CAM are then descending), and the target is positioned so that the main face 111 shown in [Fig. 2a] or opposite the position sensor 2 for a three or six cylinder engine (because the six fronts 15 spaced 120 ° CAM are then descending).
    To facilitate the identification of the face to be placed opposite the sensor as a function of the number of cylinders of the engine, it is possible to place on at least one of the faces 11A and 11B a polarizing device, that is to say a marking making it possible to identify the face in relation to the number of cylinders of the engine (indeed the direction of rotation is always the same and the type of edge best detected by a TPO type sensor also).
    In one embodiment, the toothed wheel 1 has only six teeth.
    In this case, an edge of each tooth forms one of the fronts 15 spaced 60 ° apart, and the opposite edge of four of the six teeth forms one of the fronts 14 spaced apart.
    90 °.
    There are two edges of unassigned teeth, forming a first unassigned front 16 and a second unassigned front 16 ', these fronts being of the same type (rising or falling) as the four fronts spaced 90 ° apart, and which are neither part of these fronts, nor part of the fronts spaced 60 °. Advantageously, the angular positions of these two unassigned fronts are adapted to optimize the synchronization performance of the toothed wheel, as described in more detail below.
    It can be noted that two wheel geometries exist for the same arrangement of the fronts, by reversing the type of front. Thus in [Fig. 2a] there is shown an example in which the edges 14 spaced 90 ° are rising edges, and in [Fig. 3a] there is shown an example in which the edges 14 spaced 90 ° are falling edges. On the other hand, all the angular intervals between the fronts are identical.
    We note A the minimum angular difference between one of the fronts spaced 90 ° and one of the fronts spaced 60 °. Taking into account the fact that two geometries exist for each arrangement of fronts, A can correspond:
    - at the angular distance between the edges of the smallest tooth of the toothed wheel, the two opposite edges of which include one of the fronts spaced by 90 ° and one of the fronts spaced by 60 °, if it corresponds to a high level of the wheel (see [Fig. 2a]), or
    - at the angular distance between the edges delimiting the smallest interval between two consecutive teeth delimited by edges of teeth comprising one of the fronts spaced by 90 ° and one of the fronts spaced by 60 °, if it corresponds to a low level of the wheel (see [Fig. 3a]).
    In addition, we denote B the minimum angular difference between the first unallocated front 16 and the front among the fronts spaced at 60 ° closest. B translates the angular position of this unassigned front 16.
    We also note C the minimum angular difference between the second unallocated edge 16 ′ and the edge among the edges spaced by the nearest 60 °. C translates the angular position of this second unallocated edge 16 ’.
    As for A, the angular deviations B and C can correspond to two different angular deviations, depending on whether they correspond to a high or low level of the wheel, that is to say:
    - at the angular distance of an interval between two teeth formed between the respective unallocated front and the front among the fronts spaced by the nearest 60 °, if they correspond to a low level of the wheel (see [Fig. 2a]), and
    - at the angular distance between the edges of a tooth comprising the respective unassigned front and the closest front among the fronts spaced 60 °, if they correspond to a high level of the wheel (see [Fig. 3a ]).
    If A corresponds to a high level of the wheel, then B and C both correspond to a low level of the wheel, and vice versa.
    With the notations A, B and C described above, the angular positions of the edges of the teeth making it possible to obtain four fronts of a first type spaced by 90 ° CAM and six fronts of the other type spaced by 60 ° CAM respect the following rule (in ° CAM): [0, A, 60, 90 + A, 120, 180-C, 180, 180 + A, 240, 270 + A, 300, 360-B] [0079] A, B and C are strictly positive and are constrained by the detection performance of the sensor.
    Indeed, the sensor can detect a high level of the wheel only when this high level has a length greater than a threshold, noted Lhaut. The height is therefore the minimum distance between the edges of a tooth allowing detection of the high level between the edges of the tooth by the sensor.
    Furthermore, the sensor can detect a low level of the wheel only when this low level has a length greater than a threshold, denoted Lbas. Lbas is therefore the minimum distance between the edges of two consecutive teeth delimiting an interval allowing detection of the low level between these edges by the sensor.
    By approximation, the lengths considered are those of segments connecting the high points of the edges of a tooth for Lhaut, and those connecting the points at the base of the edges of an interval for Lbas. It is also considered that these segments are substantially tangential with respect to the circular body.
    Consequently, when A corresponds to a high level, A must respect the following relationships:
    [Math. 1]
    A> and 30 - A> tan ' 1 ^)
    R r
    Where R is the radius of the wheel including the height of the tooth relative to the circular body 10, and r is the radius of the circular body of the wheel (see [Fig. 2b]).
    30-A corresponds to the angular interval between the edges delimiting the smallest interval between two consecutive teeth delimited by edges of teeth comprising one of the fronts spaced by 90 ° and one of the fronts spaced by 60 ° . This interval must be sufficient to allow the detection of a low level, and therefore of the edges delimiting it.
    In this case, B and C correspond to a low level, and more precisely to the angular opening of the interval between two teeth respectively comprising the first or the second unallocated front, and the closest front among the fronts spaced 60 ° apart. B and C must respect the following relationships:
    [Math. 2]
    B> tan- 1 ^) and 60 - B>
    60-B corresponds to the angle covered by the tooth comprising the first unassigned front 16.
    [Math. 3]
    C> tan V ---) and 60 - C> tan V——) r R [0088] 60-C corresponds to the angle covered by the tooth comprising the second unassigned front 16 ’.
    In addition, to ensure that the toothed wheel is asymmetrical in revolution, that is to say such that the profile of the teeth of any half of the wheel is different from that of the other half, B and C must be of different values. Preferably, the difference between the values of B and C includes a tolerance, greater than or equal to 5 ° CAM, for example equal to 10 ° CAM, this tolerance being linked to the detection performance of the sensor and making it possible to discriminate the mechanical tolerances of positioning and fabrication of the target.
    When A corresponds to a low level ([Fig. 3a] and [Fig. 3b]), A must check the following relationships:
    [Math. 4]
    A> tan-'C ^) and 30 - A> tan-'C ^) 30-A then corresponds to the angle covered by the smallest tooth comprising one of the fronts spaced 90 ° and the one of the fronts spaced 60 °.
    B and C then correspond to a high level, and in particular they correspond to the angle covered by the tooth respectively comprising each respective unallocated front and the closest front among the fronts spaced 60 ° apart. B and C and must verify the following relationships:
    [Math. 5]
    B> tan- 1 ^) at 60 - B>
    r R [0093] 60-B then corresponds to the angular difference between the edges of an interval between two consecutive teeth comprising the first unallocated front and the closest front among the fronts spaced 60 °.
    [Math. 6]
    C> tan X ---) and 60 - C> tan V——) r R [0094] 60-C then corresponds to the angular difference between the edges of an interval between two consecutive teeth comprising the second unassigned front 16 'and the closest front among the fronts spaced 60 °.
    In addition, in this configuration also the values of B and C must be different to ensure the rotation asymmetry of the wheel, and advantageously different with a tolerance of at least 5 ° CAM, for example 10 ° CAM and making it possible to discriminate the mechanical tolerances for positioning and manufacturing the target.
    So that the toothed wheel 1 is compatible with a variable distribution motor (VVT), it can advantageously comprise on the circumference of the circular body 10 at least two zones 17 devoid of fronts on an angle of at least 35 ° CAM , for example at least 37.5 ° CAM (corresponding to 75 ° CRK for the crankshaft) the two zones 17 being spaced 180 ° CAM. This spacing of 180 ° CAM is counted between the median angular positions of the two zones 17. These two zones are not, however, necessarily of the same size.
    Indeed, during the installation of the toothed wheel on the camshaft, each portion without front is positioned at an angular position or it is detected simultaneously with the detection of the gap of a crankshaft wheel by the corresponding sensor.
    In [Fig. 4], we have compared the teeth of a crankshaft wheel (top line - CRK) comprising two gap zones G (devoid of teeth) and those of a gear wheel of camshafts (bottom line - CAM, each figure indicated under an arrow represents a value of angle of rotation of the crankshaft in ° CRK, the value of angle of rotation of the camshaft in ° CAM being equal to half of the value indicated). The gear of the camshaft is therefore positioned so that at least one gap zone G of the crankshaft corresponds to a portion devoid of fronts of the gear of the camshaft.
    The amplitude of 35 ° CAM or more of this portion allows, even in the event of an angular offset of the camshaft to modify the angular zones of opening of the intake or exhaust valves, that the zone of the toothed wheel 1 detected by the sensor 2 simultaneously with the detection of the crankshaft gap is always devoid of front. Thus, the risk of imprecise reference linked to the detection of an edge simultaneously with the presence of the crankshaft gap is avoided.
    The presence of the two portions spaced 180 ° CAM follows from the fact that a rotation of the camshaft corresponds to two rotations of the crankshaft and therefore that the gap of the crankshaft corresponds to two portions of the toothed wheel spaced 180 ° CAM.
    In the case where the crankshaft wheel has two gap zones spaced 180 ° CRK, the toothed wheel of the camshaft advantageously has four zones comprising none of the fronts 14 spaced 90 ° nor any of the fronts 15 spaced by 60 °, at an angle of at least 35 ° CAM, spaced by 90 ° CAM, these four zones advantageously including the two zones completely devoid of front described above.
    In [Fig. 4], we have also identified the six fronts 15 spaced 60 ° CAM, which are in this case falling edges, and the four fronts 14 spaced 90 ° CAM which are rising edges.
    Referring to [Fig. 5], there is shown schematically an example of an internal combustion engine comprising a toothed wheel as described above.
    The engine M comprises three, four or six cylinders 82, in which respective pistons 80 slide by means of connecting rods 84 driven by a crankshaft 9. The crankshaft 9 also rotates by a timing belt 90 at least a camshaft 91, whose rotation successively causes the opening and closing of intake and exhaust valves 92.
    The engine can be of variable distribution: it then includes angular offset means (not shown) of the camshaft to modify the opening times of the valves with respect to an identical position of the crankshaft. The maximum offset angle is around 25 ° CAM (evening 50 ° CRK).
    The crankshaft 9 comprises a toothed wheel 93 comprising a set of teeth regularly distributed around its circumference, typically 36 or 60 teeth, with the exception of one or two gap zones, typically with one or two missing teeth.
    A sensor 94 of the angular position of the crankshaft is positioned opposite the toothed wheel 93 and is adapted to detect the passage of each tooth of the wheel.
    On the camshaft 91 or on each camshaft is mounted a toothed wheel 1 according to the above description. A TPO or level sensor 2 is positioned in front of the gear wheel and is adapted to detect the levels of the gear wheel and to deduce from a level change a rising or falling edge.
    As mentioned above, the sensor 2 can have higher detection performance for one type of edge than for the other type of edge.
    The reversible toothed wheel is then advantageously positioned, on the camshaft, during the assembly of the engine, by orienting one of its main faces towards the sensor 2 so that:
    - if the engine has three or six cylinders, the six edges spaced at 60 ° correspond to the type of edge for which the sensor 2 has superior performance, and
    - If the engine has four cylinders, the four edges spaced 90 ° correspond to the type of edge for which the sensor 2 has superior performance.
    The engine also includes a central processing unit 95 adapted to receive the detection signals from the angular position sensors of the crankshaft and the camshaft, and to deduce therefrom a state of the engine cycle at any time.
    As indicated above with reference to [Fig. 4], in the case where the engine is of the variable distribution type, the toothed wheel of the camshaft is advantageously positioned, during the assembly of the engine, so that the range of the engine cycle during which the reference space devoid of teeth of the crankshaft gear is opposite the angular position sensor of crankshaft 94 is included in the engine cycle range during which a portion of at least 30 ° CAM devoid of fronts of the gear wheel camshaft is opposite the angular position sensor 2 of the camshaft.
    权利要求:
    Claims (2)
    [1" id="c-fr-0001]
    [Claim 1] Camshaft gear (1), forming a target for a camshaft position sensor (2), the gear comprising a circular body (10) comprising two opposite main faces (11 A , 11 B), and at least six teeth (12) distributed over the circumference of the circular body, each tooth comprising two edges (13) corresponding one to a rising edge and the other to a falling front, depending on a direction of rotation of the wheel, the toothed wheel having an asymmetry of revolution, characterized in that the six teeth (12) are shaped so that the toothed wheel (1) comprises, considering the same main face and the same direction wheel rotation:
    - four fronts (14) of the same first type rising or falling, spaced 90 ° apart respectively, and
    - six fronts (15) of the same second type, respectively falling or rising, spaced respectively by 60 °.
    [Claim 2] A camshaft gear (1) according to claim 1, comprising a marking element on one of the two opposite main faces.
    [Claim 3] Toothed wheel (1) according to one of claims 1 or 2, comprising on its circumference at least two zones (17) devoid of fronts at an angle of at least 35 °, the two zones being spaced 180 °.
    [Claim 4] Toothed wheel (1) according to claim 3, comprising on its circumference four zones (17) devoid of one of the four fronts spaced 90 ° and devoid of one of the six fronts spaced 60 °, the four zones being spaced 90 ° apart.
    [Claim 5] Gear wheel (1) according to any one of the preceding claims, in which two teeth (12) each comprise one of the six fronts (15) spaced 60 ° apart and one front (16, 16 ') of the same type as the four fronts spaced at 90 °, but distinct from them, called respectively first (16) and second (16 ') unassigned fronts, and, noting:
    - At the minimum angular distance between one of the four fronts (14) spaced by 90 ° and one of the six fronts (15) spaced by 60 °,
    - B the minimum angular difference between one of the six fronts (15) spaced 60 ° and the first unallocated front (16), and
    - C the minimum angular difference between one of the six fronts (15) spaced 60 ° and the second unallocated front (16), the angular positions of the edges of the teeth of the toothed wheel are [0, A, 60, 90 + A, 120, 180-C, 180, 180 + A, 240, 270 + A, 300, 360-B].
    [Claim 6] Toothed wheel according to the preceding claim, wherein each tooth (12) corresponds to a high level of the toothed wheel and each gap between two teeth corresponds to a low level of the toothed wheel, the toothed wheel being adapted to form a target for a camshaft position sensor of the type able to detect a high or low level of the tooth and to deduce from a level variation the presence of a tooth front, and the minimum angular deviation A corresponds to a high level of the gear wheel, and is defined by the following relationships:
    [Math. 1]
    A> tan-H ^ 2 ·) and 30-A> tan ' 1 ^)
    R r where R is the radius of the toothed wheel including a height of the teeth relative to the circular body, r is the radius of the circular body, Lhaut is the minimum distance between the edges of a tooth allowing a detection of the high level between the two edges by the sensor, and Lbas is the minimum distance between the edges of two consecutive teeth delimiting an interval allowing detection of the low level between these edges by the sensor.
    [Claim 7] Gear wheel according to the preceding claim, in which the angular distances B and C correspond to a low level of the gear wheel, and are defined by the following relationships:
    [Math.
    [0002]
    2] r> i J ^ bas. . rr . r, -. i ^ top
    B> tan (- ^ -) and 60 - B> tan 1 1 ^ 1 and [Math. 3] ~. . -i ^ basy. rn „. . _i
    C> tan 1 (---) and 60 - C> tan 1 —-— r R) with C and B having different values.
    [Claim 8] A toothed wheel according to claim 5, wherein each tooth (12) corresponds to a high level of the toothed wheel and each gap between two teeth corresponds to a low level of the toothed wheel, the toothed wheel being adapted to form a target for a camshaft position sensor of the type able to detect a high or low level of the tooth and to deduce from a level variation the presence of a tooth front, and the minimum angular deviation A corresponds to a low level of the gear wheel, and is defined by the following relationships:
    [Math. 4]
    A> tan -i (L £) and 30 - A>
    r Æ where R is the radius of the toothed wheel including a height of the teeth relative to the circular body, r is the radius of the circular body, Lhaut is the minimum distance between the edges of a tooth allowing a detection of the high level between the two edges by the sensor, and Lbas is the minimum distance between the edges of two consecutive teeth delimiting an interval allowing detection of the low level between these edges by the sensor.
    [Claim 9] Gear wheel according to the preceding claim, in which the angular distances B and C correspond to a high level of the gear wheel, and are defined by the following relationships:
    [Math. 5] n . _i e ^ haut- ,, rr , r ,. _i f ^ bas
    B> tan% —-—) and 60 - B> tan 1 - v R J r) and [Math. 6] ~ (Lbas
    C> tan i (----) and 60 - C> tan 1 --R r / with C and B having different values.
    [Claim 10] Internal combustion engine (M) comprising three, four or six cylinders, a camshaft, and a toothed wheel (1) according to any one of the preceding claims mounted integral with the camshaft, in which each tooth (12) corresponds to a high level of the toothed wheel and each interval between two teeth corresponds to a low level of the toothed wheel, and the internal combustion engine (M) further comprises a position sensor (2) of the camshaft adapted to detect a high or low level of the tooth and to detect, from a level variation, a tooth front, the sensor having a greater detection performance for a type of front than for the other type of front, the toothed wheel (1) being mounted on the camshaft so that a main face (11 A, 11 B) is oriented towards the position sensor (2) of the shaft cams, the main face oriented towards the position sensor being chosen so that:
    - if the engine has three or six cylinders, the six fronts (15) spaced 60 ° apart are fronts of the type for which the detection performance by the sensor is higher, and
    - If the engine has four cylinders, the four fronts (14) spaced by 90 ° are fronts of the type for which the detection performance by the sensor is higher.
    [Claim 11] Method for assembling an internal combustion engine (M) comprising a camshaft, a toothed wheel according to any one of claims 1 to 9, and a position sensor (2) of the shaft cams of the type capable of detecting a high or low level of the toothed wheel and of detecting, on the basis of a level variation, a tooth front, the sensor having a higher detection performance for a type of front than for the other type of face, the assembly method comprising mounting the toothed wheel (1) on the camshaft so that a main face (11 A, 11 B) of the toothed wheel is oriented towards the sensor position of the camshaft, in which, if the engine has three or six cylinders, the main face oriented towards the position sensor is chosen so that the six fronts (15) spaced 60 ° are of the type for which the sensor has the best detection performance, and if the engine has four cylinders, the main face e oriented towards the position sensor is the opposite face, so that the four fronts (14) spaced 90 ° are of the type for which the sensor exhibits the best detection performance.
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    同族专利:
    公开号 | 公开日
    CN113424024A|2021-09-21|
    WO2020099625A1|2020-05-22|
    JP2022507572A|2022-01-18|
    FR3088718B1|2020-11-06|
    US20220003177A1|2022-01-06|
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    US5469823A|1993-03-31|1995-11-28|Robert Bosch Gmbh|Sensor arrangement for rapid cylinder detection in a multi-cylinder internal combustion engine|
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    US20080210021A1|2004-05-27|2008-09-04|Heinrich Steinruecken|Method and System for Making Available an Improved Phase Signal of a Phase Sensor on a Camshaft of an Internal Combustion Engine|
    US20060201238A1|2005-03-08|2006-09-14|Trapasso David J|Method and apparatus for determining rotary position|
    US20140360254A1|2013-06-11|2014-12-11|Robert Bosch Gmbh|Camshaft position pulse-generating wheel and method and device forascertaining a camshaft position|
    FR3085422B1|2018-08-29|2020-11-27|Continental Automotive France|REVERSIBLE CAMSHAFT TARGET|
    DE102021100286B3|2021-01-11|2022-03-03|Audi Aktiengesellschaft|Sensor wheel for an internal combustion engine, internal combustion engine and method for operating an internal combustion engine|
    法律状态:
    2019-11-20| PLFP| Fee payment|Year of fee payment: 2 |
    2020-05-22| PLSC| Publication of the preliminary search report|Effective date: 20200522 |
    2020-11-20| PLFP| Fee payment|Year of fee payment: 3 |
    2021-04-16| TP| Transmission of property|Owner name: VITESCO TECHNOLOGIES, DE Effective date: 20210309 |
    2021-11-22| PLFP| Fee payment|Year of fee payment: 4 |
    2022-02-11| CA| Change of address|Effective date: 20220103 |
    优先权:
    申请号 | 申请日 | 专利标题
    FR1871563A|FR3088718B1|2018-11-16|2018-11-16|REVERSIBLE TARGET FOR 3, 4 OR 6 CYLINDER ENGINES|FR1871563A| FR3088718B1|2018-11-16|2018-11-16|REVERSIBLE TARGET FOR 3, 4 OR 6 CYLINDER ENGINES|
    CN201980089176.XA| CN113424024A|2018-11-16|2019-11-15|Reversible target of three-cylinder, four-cylinder or six-cylinder engine|
    US17/294,234| US20220003177A1|2018-11-16|2019-11-15|Reversible target for a 3-, 4- or 6-cylinder engine|
    PCT/EP2019/081460| WO2020099625A1|2018-11-16|2019-11-15|Reversible target for a 3-, 4- or 6-cylinder engine|
    JP2021526637A| JP2022507572A|2018-11-16|2019-11-15|Reversible target for 3-cylinder, 4-cylinder or 6-cylinder engines|
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