Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
  • F16F15/00—Suppression of vibrations in systems; Means or arrangements for avoiding or reducing out-of-balance forces, e.g. due to motion
  • F16F15/10—Suppression of vibrations in rotating systems by making use of members moving with the system
  • F16F15/14—Suppression of vibrations in rotating systems by making use of members moving with the system using masses freely rotating with the system, i.e. uninvolved in transmitting driveline torque, e.g. rotative dynamic dampers
  • F16F15/1407—Suppression of vibrations in rotating systems by making use of members moving with the system using masses freely rotating with the system, i.e. uninvolved in transmitting driveline torque, e.g. rotative dynamic dampers the rotation being limited with respect to the driving means
  • F16F15/145—Masses mounted with play with respect to driving means thus enabling free movement over a limited range

Definitions

• the invention relates to the field of designing a vehicle engine assembly.
• the invention relates to the reduction of noise when starting a combustion engine of a vehicle. More specifically, the invention relates to a method of dimensioning a damping flywheel for a combustion engine of a motor vehicle.
• a motor vehicle combustion engine In low speed operation, a motor vehicle combustion engine generates parasitic vibrations in the drive train. Their amplitudes increase significantly on engines of small displacement, and for which a high torque is imposed at low speed.
• the presence of a double damping flywheel equipped with pendulums makes it possible to stem the propagation of vibrations in the rest of the power train.
• the pendulums of the coupling make it possible to filter the fundamental order or one of these harmonics, according to the dimensioning of the clocks of the coupling.
• the pendulum system can be positioned on a single steering wheel or on the primary of a double damping flywheel generally designated by the acronym "DVA". Alternatively, the pendulum system can be positioned on the secondary of a DVA.
• the device comprises a starting element which comprises a torsion damping mechanism with a damping mass.
• the latter is movably mounted by a rod guided in a curved notch integral with the secondary portion of the torsion damping mechanism.
• the object of the invention is to solve at least one of the technical problems posed by the prior art.
• the invention poses the new technical problem of reducing the noise of pendulums of a damping flywheel for a vehicle engine, said noise being generated by the angular decelerations of damping flywheel during starting of said engine due to its compression times.
• the invention also aims to reduce the click noise of a damping flywheel for a vehicle with a combustion engine.
• the subject of the invention is a method of dimensioning an engine assembly for a motor vehicle, the engine assembly comprising: a damping flywheel with pendulums, and an explosion engine with an output shaft on which the damping flywheel is mounted, the motor assembly having a rotatable hitch at least partially formed by the output shaft and the damping flywheel, characterized in that the method comprises the following steps: (a) taking into account the geometry of the rotating coupling, and (b) calculating a minimum inertia of the rotating coupling in order to preserve its kinetic energy when starting the combustion engine.
• the method may comprise one or more of the following characteristics, taken separately or according to all the possible technical combinations: -
• the combustion engine comprises a displacement, and during the step (b) calculation, the minimum inertia is defined as greater than or equal to the product of the engine displacement multiplied by the total mass of the pendulums, multiplied by a coefficient greater than or equal to 0.15.
• the damping flywheel comprises main springs, the pendulums being disposed outside said main springs.
• the main springs are arranged at the periphery of the coupling.
• the damping flywheel is a double damping flywheel with a primary flywheel mounted on the output shaft of the engine, and a secondary flywheel on which the pendulums are mounted, the primary flywheel and the secondary flywheel each having a moment of inertia.
• the method further comprises a step (c) defining a project inertia of the rotating coupling of the engine assembly being dimensioned, the project inertia comprising the sum of: a total inertia of a facade of accessories ; total inertia of a distribution facade; a moment of inertia of a water pump; a moment of inertia of balancing shaft; an inertia of a group including: the output shaft, an oil pump, a pulley, and a set of rods and pistons mounted on the output shaft; and a coupling member inertia; the method further comprising a step (d) comparing the project inertia defined in step (c) definition and the minimum inertia calculated in step (b) calculation.
• the damping flywheel is a double damping flywheel with a primary flywheel mounted on the output shaft of the engine, and a secondary flywheel on which the pendulums are mounted, the primary flywheel and the secondary flywheel each having a moment of inertia
• the method further comprises a step (c) defining a project inertia of the rotating coupling of the engine assembly being dimensioned, the project inertia comprising the sum of: a total inertia of a facade of accessories ; total inertia of a distribution facade; a moment of inertia of a water pump; a moment of inertia of balancing shaft; an inertia of a group including: the output shaft, an oil pump, a pulley, and a set of rods and pistons mounted on the output shaft; and a coupling member inertia; the method further comprising a step (d) comparing the project inertia and the minimum inertia
• the damping flywheel is a double damping flywheel with a primary flywheel mounted on the output shaft of the engine, and a secondary flywheel on which the pendulums are mounted, the primary flywheel and the secondary flywheel each having a moment of inertia; and the method further comprises a step (c) defining a project inertia of the rotating coupling of the engine assembly being dimensioned, the project inertia comprising the sum of: a total inertia of a facade of accessories ; total inertia of a distribution facade; a moment of inertia of a water pump; a moment of inertia of balancing shaft; an inertia of a group including: the output shaft, an oil pump, a pulley, and a set of rods and pistons mounted on the output shaft; and a coupling member inertia; the method further comprising a step (d) comparing the project inertia and the minimum inertia;
• the method further comprises a step (c) defining a project inertia of the rotating coupling of the engine assembly being dimensioned, the project inertia comprising the sum of: a total inertia of an accessory facade ; total inertia of a distribution facade; a moment of inertia of a water pump; a moment of inertia of balancing shaft; an inertia of a group including: the output shaft, an oil pump, a pulley, and a set of rods and pistons mounted on the output shaft; and a coupling member inertia; the method further comprising a step (d) comparing the project inertia defined in step (c) definition and the minimum inertia calculated in step (b) calculation and that the damping flywheel is a simple steering wheel, and motor assembly further comprises a clutch mechanism, during the step (c) definition of the project inertia, the coupling member inertia being equal to the sum of
• the minimum inertia of the rotating coupling is an equivalent inertia converted into inertia around the axis of rotation of the output shaft by the principle of the conservation of kinetic energy .
• the method comprises in between a step (e) increase of the project inertia of the rotating coupling by increasing the moment of inertia of the damping flywheel.
• the minimum inertia of the rotating coupling is a function of a product with the displacement of the engine and the mass of the clocks.
• the minimum inertia is greater than or equal to the product of the displacement of the engine multiplied by the mass of pendulums multiplied by 0.15.
• Pendulums are movably mounted relative to the damping flywheel, particularly with respect to the secondary flywheel.
• Step (e) increase is performed when the project inertia is lower than the minimum inertia.
• step (e) increase, mass is added to the primary flywheel of the damping flywheel.
• step (c) definition the inertias are assigned coefficients corresponding to the reduction ratios relative to the output shaft, or the squares of said reduction ratios.
• the output shaft has a deceleration acyclism.
• the inertia of the coupling member is equal to the moment of inertia of the primary flywheel when the deceleration acyclism multiplied by the addition of the moments of inertia of the primary flywheel and the clutch mechanism is greater than the friction torque and stiffness of the double damping flywheel at a travel of 10 °.
• the coupling member inertia is equal to the sum of the moment of inertia of the primary flywheel, the moment of inertia of the secondary flywheel, and the moment of inertia of the clutch mechanism; when the deceleration acyclism multiplied by the addition of the moments of inertia of the primary flywheel and the clutch mechanism is less than or equal to the friction torque and stiffness of the double damping flywheel at a displacement of 10 °.
• the invention also relates to a motor vehicle comprising: a damping flywheel with movable pendulums, and an internal combustion engine with a displacement and an output shaft on which the damping flywheel is mounted, the output shaft and the damping flywheel at least partially forming a rotating hitch, characterized in that the inertia of the rotating hitch is greater than or equal to the product of the engine displacement multiplied by the total mass of the pendulums, multiplied by 0.15.
• each object of the invention is also applicable to the other objects of the invention.
• each object of the invention is combinable with other objects.
• the objects of the invention are also combinable with each embodiment.
• the invention proposes to define an inertia of the rotating coupling to clipping the deceleration peaks. Defining the minimum inertia of the coupling according to a product of the cylinder capacity and the mass of the clocks remains a complementary approach making it possible to reduce the clocks' noises. Correct the above mentioned products by a coefficient greater than or equal to 0.15; allows a finer optimization of noise reduction and added mass in order to correct project inertia.
• Figure 1 shows a motor assembly for a motor vehicle according to the invention.
• Figure 2 is a section of a double damping flywheel pendulum according to the invention.
• FIG. 3 shows, from the front, a secondary flywheel of double damping flywheel with pendulum according to the invention
• Figure 4 is a graph of the angular accelerations of the primary flywheel and the sound pressure generated by a damping flywheel according to the invention.
• Figure 5 is a diagram of a method of dimensioning a motor assembly for a motor vehicle according to the invention.
• an inertia is considered as a rotational inertia, and is expressed in Kg.m2, just as the moments of inertia.
• Rotational inertia is considered according to the axes of rotation around which the various parts rotate in the motor assembly, respectively in the vehicle.
• the cubic capacity is considered in liters and the mass of the clocks is expressed in kilos.
• Figure 1 symbolically presents a set 2 engine 4 for a motor vehicle (not shown).
• the assembly 2 comprises a thermal engine 4, for example four times.
• the engine 4 is of the internal combustion type, especially explosion.
• the engine 4 comprises a crankshaft 6 also forming the output shaft 8 of the engine 4.
• the output shaft could also be a camshaft.
• the crankshaft 6 receives a series of pistons 10 via rods 12 which are each pivotally mounted relative to the pistons 10 and relative to the crankshaft 6.
• the sections and the strokes of the pistons 10 define the displacement of the engine 4. Its displacement can be between 1 L and 3 L. It can be equal to 1, 2 L. In the present example, four pistons 10 are present, however the The invention also relates to three-piston engines, or any other number of pistons.
• a rotating hitch 14, or movable hitch may form a subassembly. It can group the rotating parts driven in rotation by the engine 4, in particular via its output shaft 8, that is to say thanks to the crankshaft 6, which is also part of said rotating coupling 14.
• the rotating parts considered can being those which are driven directly or indirectly by the output shaft 8, and / or those with fixed coupling with the output shaft 8.
• the rotatable hitch 14 may also comprise an oil pump 16, a pulley 18, a water pump 20, a balancer shaft 22.
• the rotatable hitch 14 is optionally completed by an accessory front 24, and / or a distribution facade 26.
• Each of its entities comprises moving parts rotating along a proper axis. Some entities may have a common axis of rotation.
• the output shaft 8 is connected to a damping flywheel 28 or damping flywheel.
• the latter can be connected or integrated in the clutch mechanism 30, allowing a rotational decoupling of the gearbox 32.
• the latter can be engaged with drive wheels (not shown) of the vehicle.
• the engine 4 manages to propel the vehicle.
• the gearbox 32 is considered to be outside the rotary coupling 14, in particular because of its uncoupling with the output shaft 8 during the starting phases, thanks to the clutch mechanism 30.
• FIG. 2 is a sectional view of a damping flywheel 28 of which only one half is represented above its axis of rotation 34.
• the damping flywheel 28 can correspond to that described in Figure 1.
• the damping flywheel 28 may be of the double flywheel type. It is commonly called “double damping flywheel”, and is usually referred to by the acronym DVA. It may have a primary flywheel 36 and a secondary flywheel 38 which are respectively fixed to the output shaft 8 and to a secondary shaft 40; these trees being in particular decoupled in rotation.
• the flywheels (36; 38) are pivotable relative to each other about the axis 34, and can be hinged together by a central bearing.
• the flywheels (36; 38) can be connected by main springs 42, also called main arched springs or external springs.
• the main springs 42 can marry the perimeter of the double damping flywheel. When pivoting one flywheel relative to the other, the springs 42 are compressed along the circumference, which allows to filter motor acyclism. This function reduces the clashes, and thus filters some vibrations.
• mass 44 or flyweights, during the concetion of the damping flywheel 28.
• flywheels can be linked to the primary flywheel 36, for example on its face opposite the engine, or on its perimeter.
• the secondary flywheel 38 may comprise a sail 46 receiving pendulums 48.
• the latter are made movable relative to the secondary flywheel 38 through their mounting via rollers 50.
• the pendulums 48 can shift along the circumference. They can switch.
• the pendulums may be identical and angularly distributed around the axis of rotation 34, and on both sides of the web 46 so as to form pairs traversed by the web.
• the pendulums 48 perform counter-movements opposing vibrations of a given frequency.
• the mass of pendulums 48 is previously imposed.
• clocks 48 In order to increase the efficiency of clocks 48 for a given order, these can be placed outside the springs 42. They can be shifted along of the axis 34 relative to the springs 42, and may in particular radially overlap. At this position, the centers of gravity of the pendulums 48 are remote from the axis 34, so that the centrifugal force they undergo increases.
• the pendulums 48 such as the web 46 may have guide grooves 52 in which the rollers 50 are placed. Radial play, that is to say perpendicular to the axis of rotation 34, can be provided between the rollers. 50 and each guide grooves 52.
• Figure 3 shows a front part of the damping flywheel 28 such as that of Figure 2.
• One pendulum 48 of the pair is visible, the other behind the web 46 being masked.
• the pendulums 48 of the pair can be fixed rigidly to one another by means of pins 54, or any other equivalent element.
• the pendulum 48 generally occupies an angular zone of the damping flywheel 28, and therefore of the secondary flywheel 38.
• the rollers 50 and the guide grooves 52 are visible. The latter form arcuate trajectories for the rollers 50. Arched trajectories may have convex shapes oriented towards the axis of rotation 34.
• the present teaching can also be applied to a double damping flywheel with internal pendulums, that is to say where the pendulums are placed inside the main springs. Therefore, the main springs can overlap the pendulums along the axis of rotation. This configuration reduces the effect of pendulums on the filtration of a harmonic.
• Figure 4 is a graph of the angular accelerations of the motor output shaft and the acoustic pressure that are measured at the start of the engine. These physical quantities are represented on the same scale of time in abscissa.
• the graph comprises an upper part having the angular accelerations of the engine measured in rad / s 2 , and a lower part having the acetic pressure measured in pascal (Pa) in the damping flywheel.
• This sound pressure here is characteristic of the noticeable noises in the form of clicks.
• the upper part of the graph comprises a curve C1 representative of the angular accelerations and decelerations of a motor assembly dimensioned according to the invention.
• the positive values illustrate accelerations and the negative values of the decelerations, which highlights the motor acyclism as presented in Figure 1.
• Curve C2 is representative of a motor assembly according to the state of the art. For this motor assembly, the decelerations reach -1000 rad / s 2 . These angular decelerations are greater than for the invention since the values of the curve C1 remain above -750 rad / s 2 . Therefore, the deceleration peaks according to the invention remain of less amplitude.
• curve C3 represents a spectrum of acoustic pressure variations for the engine assembly dimensioned according to the invention
• curve C4 represents a spectrum of acoustic pressure variations for a motor assembly according to the state of the art.
• the curve C5 is representative of a steering wheel motor without clocks. This curve C5 being of less amplitude, it highlights the impact of the pendulums on the measured noises.
• the first noise peak of the curves C5, C3 and C4 is the noise of the starter and not the clocks, it is the following peaks of the curves C3 and C4 that truly correspond to the sounds of the clocks.
• curve C3 reflects a quieter mode of operation than for curve C4, that is, that is to say that the assembly according to the invention emits sounds more discreet than according to the state of the art.
• the damping flywheel becomes silent, or sufficiently silent according to a predefined acoustic comfort criterion which depends on the position of the microphone relative to the position of the pendulums. In our present case, this criterion can be an acoustic pressure lower than +/- 2Pa.
• FIG. 4 makes it possible to carry out a time parallel between the most important deceleration peaks and the noise peaks, which the invention has precisely done. It is remarkable that the strongest negative peaks of curve C2 correspond to peaks of curve C4. Similarly, the negative peaks of the curve C1 correspond to peaks of the curve C3. Thanks to the invention, it has emerged that correct decelerations of the tree by a minimum inertia can reduce the clicking noise clocks.
• Figure 5 is a diagram of the sizing process of a motor assembly for a motor vehicle.
• the motor unit may be identical to that described with reference to FIGS. 1 to 3, and the motor may have an acyclism as in FIG. 4.
• the method may comprise the following steps, for example carried out in the following order:
• step (b) calculation 102 the minimum inertia is defined as greater than or equal to the product of the displacement of the engine and the mass of the clocks; multiplied by: 0.15.
• Step (b) calculation 102 alone manages to provide a solution to the technical problem; the other steps being optional.
• Steps (b) calculation 102 and (c) definition 104 can be performed simultaneously. They may include identical data.
• the project inertia comprises the sum of: the total inertia of the accessories facade; the total inertia of the distribution façade; the moment of inertia of the water pump; the moment of inertia of the balancer shaft; the inertia of a group including: the output shaft, the oil pump, the pulley and a set of rods and pistons mounted on the output shaft, or all their combinations possible and imaginable; and a coupling member inertia.
• the sum can include all the inertias and moments of inertia listed above, or all their possible and imaginable combinations.
• the inertia of the set of rods and pistons can be obtained by converting their kinetic energy which is transmitted to the crankshaft.
• the output shaft has a deceleration acyclism. Deceleration acyclism can be measured in rad / s 2 . It can be theoretical. It can be obtained by simulation for a motor assembly being dimensioned.
• the coupling member inertia is defined as a function of the behavior of the damping flywheel in response to the excitations generated by the motor. This choice of inertia coupling member is intended to reflect the fact that the primary and secondary flywheels are sufficiently coupled or not. If the primary and secondary parts are sufficiently coupled, especially when the bonding torque is sufficiently large, the moment of inertia of the abutment and the moment of inertia of the clutch mechanism of the DVA are taken into account to limit the motor acyclism. Thus, the effects of these moments of inertia are taken into account in reducing the level of crankshaft decelerations during engine starts.
• the inertia of the coupling member is equal to the inertia of the primary flywheel.
• the secondary flywheel does not sufficiently follow the primary flywheel so that its inertia contributes to smoothing the angular decelerations of the output shaft, and therefore of the crankshaft.
• the angle of 10 ° can correspond to the hysteresis slide in b DVA, this hysteresis slide being generated in particular by friction rings.
• the inertia of the coupling member is equal to the moment of inertia of the primary flywheel when the deceleration acyclism multiplied by the addition of the moments of inertia of the secondary flywheel and the clutch mechanism is greater than the friction and stiffness couple of double damping flywheel with a travel of 10 °.
• the forces that bind the secondary flywheel to the primary flywheel after 10 ° of secondary angular displacement relative to the primary of the DVA can be equal to the friction torque between the flywheels of the DVA, plus the stiffness torque of the DVA over 10 ° of DVA travel.
• the friction cut can be the basic friction of the DVA, possibly increased by the hysteresis drawer if this drawer is present and if it is triggered at an angle of less than 20 °, that is to say for a travel angle of the secondary flywheel relative to the primary flywheel less than +/- 10 °.
• the coupling element inertia is equal to the sum of the moment of inertia of the primary flywheel, the moment of inertia of the secondary flywheel, and the moment of inertia of the clutch mechanism; as soon as the motor generates an excitation less than or equal to a force coupling the primary flywheel to the secondary flywheel.
• This coupling force being measured at an angular displacement of 10 ° between the primary flywheel and the secondary wheel.
• the secondary flywheel is sufficiently linked to the primary flywheel to soften the decelerations.
• the damping flywheel is a simple steering wheel.
• the inertia of the coupling member is the addition of the moment of inertia of the single flywheel and the moment of inertia of the clutch mechanism.

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• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Acoustics & Sound (AREA)
• Aviation & Aerospace Engineering (AREA)
• Mechanical Engineering (AREA)
• Connection Of Motors, Electrical Generators, Mechanical Devices, And The Like (AREA)
• Vibration Prevention Devices (AREA)
• Hybrid Electric Vehicles (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=62684883

Family Applications (1)

Country Status (3)

Family Cites Families (8)

• 2018
  • 2018-03-26 FR FR1852596A patent/FR3079273B1/fr active Active
• 2019
  • 2019-02-13 EP EP19711150.3A patent/EP3775614A1/de active Pending
  • 2019-02-13 WO PCT/FR2019/050315 patent/WO2019186000A1/fr unknown

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