Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01M—LUBRICATING OF MACHINES OR ENGINES IN GENERAL; LUBRICATING INTERNAL COMBUSTION ENGINES; CRANKCASE VENTILATING
  • F01M13/00—Crankcase ventilating or breathing
  • F01M13/04—Crankcase ventilating or breathing having means for purifying air before leaving crankcase, e.g. removing oil
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01M—LUBRICATING OF MACHINES OR ENGINES IN GENERAL; LUBRICATING INTERNAL COMBUSTION ENGINES; CRANKCASE VENTILATING
  • F01M13/00—Crankcase ventilating or breathing
  • F01M13/04—Crankcase ventilating or breathing having means for purifying air before leaving crankcase, e.g. removing oil
  • F01M2013/0433—Crankcase ventilating or breathing having means for purifying air before leaving crankcase, e.g. removing oil with a deflection device, e.g. screen

Definitions

• the present invention relates to an oil decantation system, and more specifically to a system for extracting the oil contained in crankcase gases of a heat engine, in particular a motor vehicle engine.
• crankcase gases In an internal combustion engine, there are several causes causing the emission of highly charged gas in fine oil droplets (having a size that can vary approximately from 0.01 ⁇ to 10 ⁇ ) and which are called “crankcase gases”. or “blow-by gas”.
• crankcase gases can result from leaking of the segments from the combustion chamber to the piston volumes, and / or from the turbocharger bearing leakage from the turbine and compressor bodies to the crankcase by the return of the engine.
• oil, and / or leaks through the valve stem seals from the intake and exhaust manifolds to the cylinder head, and / or leakage of the oil pump gases from the braking circuit to the cylinder head.
• Crankcase gases are usually composed of combustion gases
• crankcase gases mainly water, carbon dioxide and nitrogen
• unburned gases air, fuel and nitrogen
• oil oil
• the oil concentration of the crankcase gases is specific to each engine.
• the flow rate of these crankcase gases can vary over a range from approximately 50 L / min to 350 L / min, this flow being a function of the type of engine (petrol / diesel), its capacity, its age, and engine technology.
• crankcase gases must absolutely be re-aspired. This recirculation of gases is possible, by connecting the low engine (oil sump) to the engine air intake line (the vacuum is used) generally via the cylinder block and the cylinder head cover. However, these gases must be treated before being reinjected at the intake, to comply with pollution standards and to limit oil consumption.
• crankcase gases enter a chamber of section much greater than the crankcase circuit.
• This ratio of section generates a decrease in speed of the same ratio, and such a slowing of the gas flow allows the oil droplets to be deposited on the bottom of the settler.
• This decantation principle allows only large particles of oil to be treated, and therefore lacks efficiency in the treatment of the oil spray contained in the crankcase gases.
• crankcase gases pass through a quibbled zone generating, prior to impact on a wall, a succession of point accelerations of the flow of gas to be treated and decelerations by increasing the passage section.
• This principle also has the disadvantage of not allowing a treatment of any type of oil particle, since only the large and medium particles (generally> 2 ⁇ ) are extracted from the crankcase gas.
• such a quenching settling system can generate high pressure losses under a high crankcase gas flow.
• the solution proposed in the document WO 2007/075018 published on July 5, 2007 makes it possible to reduce the losses due to the variations of the flow of crankcase gas in a settling device by baffling, but the proposed arrangement is complex to implement. and still does not treat any type of oil particle.
• cyclone settling Another possibility is cyclone settling.
• This solution consists of bringing the casing gases into a casing of generally conical or cylindrical shape, at the top and tangentially to the inner surface of the casing whose specific shape makes it possible to swirl the flow of crankcase gas, that is, to form a cyclone. Rotating the crankcase gases allows the centrifugal force to be used to separate the oil droplets from the gas.
• the purified gases are sucked upwards in the lower part of the cyclone by a vertical pipe located in the center of the cyclone. Decanted oil droplets flow into the bottom of the cyclone.
• Coalescing media settling systems have also been developed.
• a housing enclosing a coalescing media through which the crankcase gas flows.
• This coalescing media consists of a fiber entanglement and is intended to capture the oil droplets so that they flow along the fibers and agglomerate together to form drops of oil of greater size which, subject to gravity, flow in the lower part of the media and are thus removed from the stream.
• One of the major problems of such a system lies in its maintenance. Indeed, when the media is crossed, it is loaded with impurities (including combustion residues) that will foul it, which increases its loss of charge if it is not cleaned regularly.
• An object of the present invention is therefore to provide an oil settling system contained in the crankcase gases of a motor vehicle engine that solves at least one of the aforementioned drawbacks.
• an object of the present invention is to provide an oil settling system contained in crankcase gases of a motor vehicle engine, which is effective regardless of the flow rate of the crankcase gas flow, and or whose associated pressure loss remains low regardless of the flow rate of the crankcase gas flow.
• Yet another object of the present invention is to provide an oil settling system contained in the crankcase gases of a motor vehicle engine, which is adapted to remove from the flow of crankcase gas any type of oil particles. , both fine particles of oil of the order of 0.01 ⁇ , and large particles of the order of 10 ⁇ .
• an oil settling system contained in the crankcase gases of a heat engine comprising a separation device intended to be interposed in a crankcase circulation circuit, characterized in that separation comprises at least one circulation member formed in an elastic material and comprising an outlet section having a variable diameter as a function of the flow of crankcase gas.
• the circulation member is a channel having a narrowed shape, with an inlet section wider than the exit section.
• Preferred but not limiting aspects of this settling system, taken alone, are the following:
• the system further comprises an impact device comprising at least one impact wall positioned downstream of the outlet section of the circulation member for intercepting the flow of crankcase gas from the circulation member,
• the impact wall has an impact surface in a material promoting the retention of the oil contained in the crankcase gases.
• the impact wall has an impact surface comprising a filtering medium, preferably of a coalescent nature.
• the impact wall has an impact surface comprising a screen
• the impact wall has a porous or multi-faceted impact surface, the impact wall has a second inclination, the second inclination being perpendicular to the inclination towards the first exit orifice,
• the circulation member is formed such that the position of the outlet section with respect to the impact wall varies as a function of the flow of crankcase gas
• the circulation member has a shape to prevent the introduction of a countercurrent flow of the flow of the crankcase gases
• the circulation member has substantially the shape of a beak.
• the separation device comprises a plurality of circulation members distributing the flow of crankcase gas at the separation device from an upstream zone to a downstream zone in the direction of the crankcase gas flow
• the system further comprises a housing with the separating device forming a settling chamber at the outlet of the circulation member, said settling chamber having at least one first outlet orifice for the removal of the oil recovered from the settling chamber at the level of the settling chamber; crankcase gas and at least a second outlet for evacuation of purified crankcase gases.
• the impact wall is arranged in the discharge chamber in an inclined manner towards the first outlet orifice.
• the settling chamber further comprises at least one inlet for the admission of the crankcase gases to the interior of the settling chamber, the separating device being placed inside the settling chamber so as to form the settling chamber on the side of the first and second outlets and an inlet chamber at the inlet port.
• Figure 1 is a sectional view illustrating the separator of the settling system according to the invention
• Figure 2 is a sectional view illustrating the operation of the separator of the settling system illustrated in Figure 1;
• Figure 3 is a sectional view illustrating the different adjustment parameters of the separator of the settling system illustrated in Figure 1;
• Figure 4 is a sectional view illustrating another type of separator of the settling system according to the invention.
• Figure 5 is a perspective view showing the settling system according to the invention.
• Figure 6 is a side view of the settling system illustrated in Figure 5;
• Figure 7 is a front view showing the interior of the settling system shown in Figure 5;
• FIG. 8 is a view along section A-A showing the inside of the settling system illustrated in FIG. 5.
• a decantation system intended to be integrated in the architecture of a heat engine, in particular a motor vehicle, is described here.
• Such a settling system is preferably integrated in the (s) settling circuit (s) crankcase gases, also called blow-by gases. It is used to remove and recover the oil contained in the crankcase gases, so as to purify these crankcase gases before they are reinjected into the combustion circuit in particular. It is called purified crankcase gas, the crankcase gases having been treated by the proposed settling system, that is to say crankcase gases in which the amount of oil remaining is very low, or even zero.
• the proposed settling system comprises a separation device intended to be interposed in the crankcase circulation circuit, this separation device
• the section of output of the circulation member 21 increases when the flow of the crankcase gases increases.
• the separation device 20 comprises at least one circulation member 21 whose function is to regulate the flow of crankcase gas flowing from an upstream zone towards a downstream zone in the direction of flow of the crankcase gases. More specifically, the circulation member 21 is formed to limit the variations in speed of the gas flow at the outlet of the separation device 20. According to a preferred embodiment, the circulation member 21 is formed so that the speed of this gas flow at the outlet of the separation device 20 is substantially constant regardless of the flow rate of the inlet crankcase gas flow.
• the separating device 20 preferably comprises a plurality of circulation members 21 whose number and dimensions are optimized according to the characteristics of the casing gas flow to be treated, such as in particular the operating flow range.
• the circulation member (s) (21) are preferably positioned on a support (23), which is a part that is interposed in the crankcase circulation circuit so that the crankcase gases necessarily flow through the circulation members. 21.
• the circulation members 21 may be arranged in line, or in parallel, or in another configuration, according to the sizing of the crankcase circulation circuit and the space available in the engine block of the vehicle.
• a settling system comprising a plurality of separation devices 20 placed in series in the crankcase circulation circuit, that is to say one after the other in the gas flow.
• This arrangement may for example be considered for successively treating the gas according to particular characteristics, for example for a treatment of oil particles of different sizes.
• the circulation member 21 is a pipe having a narrowed shape, with an inlet section (upstream in the direction of flow of the crankcase gases) wider than the outlet section (downstream in the direction flow of the crankcase gases).
• a conduit terminated by a section restriction The fact that the outlet section is both restricted and of variable diameter allows the crankcase gas to increase the speed of circulation of the crankcase gases, while maintaining a speed of this gas flow at the outlet of the separation device substantially. constant regardless of the flow rate of the inlet crankcase gas flow. Increasing the flow rate of the crankcase gases improves the settling of the gases in the separation device 20. In particular, the impaction of the crankcase gases at high speed on an impact wall 30 as described below.
• the circulation member 21 may for example have substantially a nozzle shape as shown in Figures 1 and 2. When no flow through this conduit as shown in Figure 1, the outlet of this conduit 21 may be closed this closure may for example be constrained by the shape and elasticity of the circulation member 21.
• the conduit opens at its end, by the force exerted by the flow of the crankcase gases, this opening allowing the passage of the crankcase gases from an upstream zone to a downstream zone in which the settling takes place.
• the circulation member 21 could also have a slightly more complex shape, comprising for example a substantially tubular inlet portion and an outlet portion extending the inlet portion and formed of several convergent tongues at the outlet of the outlet. circulation member 21 to close the outlet section.
• the elasticity of the arrangement allows these tabs to deviate when a flow passes through the flow member from the inlet portion, so as to enlarge the diameter of the outlet section.
• a circulation member 21 comprising four tabs arranged substantially in a cross.
• the separation device 20 of the settling system can be directly interposed in the crankcase circulation circuit but it is preferably associated with a settling chamber 10 which promotes the settling downstream of the separation device 20.
• the settling chamber 10 is provided to form with the separating device 20 a settling chamber 15 at the outlet of the circulation member 21.
• the settling chamber 10 comprises, at this settling chamber 15, at least a first outlet orifice 12 for discharging the oil recovered from the crankcase gases and at least a second outlet orifice 13 for evacuation of the purified crankcase gases.
• the first outlet port 12 can be connected to the oil circuit of the engine, which allows recycling of the oil recovered from the crankcase gases.
• the second outlet port 13 is in turn generally connected to the air intake circuit of the engine. This configuration also makes it possible to exploit the depression due to the air intake circuit for the circulation of the crankcase gases through the settling chamber 10.
• the settling chamber 10 further comprises at least one inlet port 1 1 for the admission of the crankcase gases inside the settling chamber 10, the separating device 20 being able in this case case to be positioned inside the settling box 10 separating the interior space of the housing two-chamber settling chamber: the settling chamber 15 on the one hand, and on the other hand an inlet chamber 14 at the inlet orifice January 1.
• the settling system associates the particular architecture of the separation device 20 with an impact device 30 finalizing the separation between the oil and the crankcase gases, which allows even more efficient decantation of the oil contained in the crankcase gases.
• the impact device 30 preferably comprises at least one impact wall 30 which is positioned downstream of the circulation member with respect to the flow of the crankcase gases in order to intercept the flow of crankcase gas from the body 21, so that the stream of crankcase gas leaving the circulation member 21 impact the impact wall 30.
• the impact wall 30 is arranged opposite the outlet section of the circulation member 21.
• the impact device is preferably placed inside the settling chamber 15.
• the impact wall 30 is preferably arranged in the settling chamber 15 in an inclined manner towards the first outlet orifice 12, this impact wall 30 being positioned opposite the outlet orifice of the circulation member. 21.
• This inclined impact wall 30 is positioned relative to the circulation member 21 so as to promote the separation of the oil relative to the gas at the moment of impact. Due to the particular shape of the circulation member 21, the casing gas flow has a speed at the output of the separation device which is substantially constant, or at least a speed which varies only slightly compared to the variations. flow rate of the crankcase gas flow.
• this particular architecture of the separation device 20 associated with the impact device 30 makes it possible to ensure effective separation of the oil with respect to the gas, whatever the flow rate of the crankcase gases since their impact on the wall of the impact 30 will be the same.
• the impact wall 30 is provided to promote separation and recovery of the oil relative to the gases at the moment of impact.
• the impact wall 30 may for example comprise an impact surface 31, flat or curved, the surface state is chosen to promote the capture of the oil droplets contained in the gas.
• the impact surface 31 may for example comprise or consist of a filter medium, such as a coalescent media, that is to say a material comprising synthetic microfibers or glass fibers that may have hydrophobic properties and / or or oleophiles.
• the impact wall 30 may further comprise a screen for the collection of oils. It can also be formed in a porous element that will promote the recovery of oils. It can also be multifaceted.
• the impact wall 30 may also comprise an organic element.
• the performance of the settling, in particular the performance of the separation and the recovery of the oils contained in the crankcase gases at the level of the impact wall 30 can be optimized according to the following criteria:
• the settling system is dimensioned by playing on several parameters, alone or in combination, which are illustrated in FIG.
• the circulation member 21 is formed so that the position of the outlet section 22 with respect to the impact wall 30 varies as a function of the flow of crankcase gas.
• the flexible duct forming the circulation member 21 may be designed so as to modify the impact position of the casing gas flow on the impact surface 31 as a function of the conditions of the operation (flow, pressure) and thus vary the parameter d mentioned above, that is to say the distance between the output end of the circulation member 21 and the impact wall 30. This result can be obtained by deformation of the geometry of the flexible conduit.
• the circulation member 21 has a shape to prevent the introduction of a countercurrent flow of the crankcase flow. The circulation member 21 thus forms a non-return valve thereby preventing the introduction of a flow in the opposite direction in the intended direction of circulation of the crankcase gases.
• the decanting system may consist mainly of a circulation member 21 of elastic flexible material, of elastomer type, the other parts of the system, in particular the settling chamber 10 and / or the impact wall 30, if appropriate, being able to be made of thermoplastic material, thermosetting, or any other composite material, aluminum or in a metal alloy.
• the support 23 of the separating device 20 is, for example, injected in thermoplastic material of polyamide type and the conduit flexible forming the circulation member 21 is overmolded on the support 23 of a material of the elastomer type.
• the cohesion between the two types of parts can be ensured by chemical and / or mechanical type bonding.
• the seal between the separating device 20 and the settling chamber 10 can also be ensured by the addition or overmoulding of a flexible element forming a seal.
• Figures 5 to 8 illustrate a particular embodiment of the proposed settling device, optimized for the treatment of crankcase gas in a gasoline engine with 6 cylinders, flowing with a flow rate ranging between 80 L / min and 180 L / min.
• These circulation members 21 are arranged so that the distance d is of the order of 3 mm. Moreover, the angle of inclination ⁇ of the impact wall 30 is of the order of 70 °.
• the circulation members 21 are formed of elastomer and associated with a given geometry which thus define the permeability P of the system.
• the settling system proposed is very effective regardless of the size of the oil particles to be separated.
• crankcase gas flow rates 80 L / min, 135 L / min or 180 L / min.
• crankcase gas flow rates 80 L / min, 135 L / min or 180 L / min.

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• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Lubrication Details And Ventilation Of Internal Combustion Engines (AREA)

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• 2012
  • 2012-04-25 FR FR1253783A patent/FR2989995B1/fr active Active
• 2013
  • 2013-04-24 EP EP13719791.9A patent/EP2841724B2/de active Active
  • 2013-04-24 WO PCT/EP2013/058483 patent/WO2013160346A1/fr active Application Filing
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