Intake manifold of an internal combustion engine with a blow-by gas channel for recirculating blow-by gas from a crankcase into a fresh air channel.

Abstract

Intake manifold of an internal combustion engine with a blow-by gas channel (18) for returning blow-by gas from a crankcase to a fresh air channel (12) of an intake manifold (10) upstream of a compressor (14), wherein the blow-by gas channel (18) has an inlet nozzle (20) in the region of an outlet (16) of the blow-by gas channel (18) into the fresh air channel (12), wherein the inlet nozzle (20) has at least one projection (22) with a length LV projecting into the flow cross-section of the fresh air channel (12), which reduces the flow cross-section available for the fresh air at least in a longitudinal section extending over a part of the length LE of the inlet nozzle (20) compared to the area of ​​the fresh air channel (12) immediately upstream of the projection (22), characterized in that a) the projection (22) with length LV extends from an upstream beginning (26) of the inlet nozzle (20) in the flow direction F of the fresh air over a part of the length LE of the inlet nozzle (20) and the penetration depth of the projection (22) decreases continuously and linearly to zero from a maximum penetration depth Emax at the upstream beginning (26) of the inlet nozzle (20) or b) the projection (22) extends over a length L1 starting with a maximum penetration depth Emax at the upstream beginning (26) and the penetration depth is constant over the length L1 and the penetration depth of the projection (22) decreases continuously and linearly to zero downstream of the length L1.

Description

[0001] The invention relates to an intake manifold of an internal combustion engine with a blow-by gas channel for returning blow-by gas from a crankcase to a fresh air channel according to the preamble of claim 1. In particular, the invention relates to the design of an outlet of a blow-by gas channel into a fresh air channel, preferably for internal combustion engines of motor vehicles.

[0002] In engines turbocharged with exhaust gas turbochargers, a vacuum is generated for crankcase ventilation, particularly using the intake manifold of the turbocharger upstream of the compressor. At low engine speeds, especially below 2000 rpm, during turbocharged operation, and thus with low turbocharger speed or low mass flow of fresh gas through the turbocharger, there may not be sufficient vacuum available to vent the crankcase or to actively expel enough blow-by gas from the crankcase.

[0003] From DE 10 2015 008 291 A1, a method for operating an internal combustion engine with an intake manifold and a compressor of an exhaust gas turbocharger is known. By means of a recirculation device, at least a portion of the compressed air can be diverted downstream of the compressor, recirculated, and reintroduced into the intake manifold at a feed point upstream of the compressor. It is also described how the recirculated compressed air is directed to the feed point via a Venturi nozzle in order to generate a vacuum with the aid of the diverted air to effect crankcase ventilation.

[0004] From DE 10 2010 029 150 A1, a system for an engine with a variable venturi nozzle is known, which is said to include a movable "egg" and is coupled to an inlet of the engine. Furthermore, reference is made to vacuum-generating devices that may be provided additionally.

[0005] From DE 10 2011 010 289 A1, from US 2004 / 0 069 286 A1 and from US 2002 / 0 002 968 A1, intake tracts of internal combustion engines with a blow-by gas channel for returning blow-by gas from a crankcase to a fresh air channel of an intake tract are known, which have inlet nozzles leading into the fresh air channel, which can be considered to have the features of the preamble of claim 1.

[0006] The invention is based on the objective of providing an intake tract for an internal combustion engine with which a crankcase can be vented particularly efficiently in a simple manner.

[0007] The problem is solved according to the invention with the features of claim 1. Further practical embodiments and advantages of the invention are described in connection with the dependent claims.

[0008] An intake manifold according to the invention for an internal combustion engine comprises a blow-by gas channel for recirculating blow-by gas from a crankcase into a fresh air duct upstream of a compressor, wherein the compressor is part of an exhaust gas turbocharger. The blow-by gas channel has an inlet nozzle in the region of its outlet into the fresh air duct. The inlet nozzle further comprises at least one projection with a length LV extending into the flow cross-section of the fresh air duct, which reduces the flow cross-section available to the fresh air at least in a longitudinal segment extending over a portion of the length LE of the inlet nozzle, compared to the area of ​​the fresh air duct immediately upstream of the projection. The orientation of the lengths specified above corresponds to the main flow direction of the air flowing through the fresh air duct, i.e.,the longitudinal direction of the fresh air duct in the area of ​​the inlet nozzle.

[0009] By forming at least one projection of length LV on the inlet nozzle, as described above and extending over a portion of its length LE, an additional negative pressure is easily generated in the blow-by gas channel, thus improving the delivery of blow-by gas from the crankcase. This is because the (preferably slight) reduction in cross-section caused by the projection locally increases the flow velocity in the fresh air channel, thereby generating additional negative pressure in the blow-by gas channel. A particular advantage is that an intake tract according to the invention can be implemented by simply adapting the inlet nozzle geometrically, with virtually no additional costs or installation space requirements.

[0010] For the purposes of the invention, a projection is defined as any area provided or formed in the region of the inlet nozzle that extends from the inlet nozzle transversely to the main flow direction through the fresh air duct into the fresh air duct and thus reduces its cross-sectional area. The formation or arrangement of such a projection on the inlet nozzle can be achieved particularly simply and cost-effectively by a projecting arrangement and suitable design of the pipe end of a tubular inlet nozzle. The following features are also provided: a) The projection of length LV extends from an upstream beginning of the inlet nozzle in the direction of flow F of the fresh air over a part of the length LE of the inlet nozzle, and the penetration depth of the projection decreases continuously and linearly from a maximum penetration depth Emax at the upstream beginning of the inlet nozzle to zero or b) the projection extends over a length L1 starting with a maximum penetration depth Emax at the upstream beginning, and the penetration depth is constant over the length L1, with the penetration depth of the projection decreasing continuously and linearly to zero downstream of the length L1.

[0011] The intake tract according to the invention is not only simple and cost-effective to implement, but also a robust and durable design for the long-term improvement of crankcase ventilation. It is also advantageous that no structural modification of the fresh air duct is required to realize the invention. An intake tract according to the invention can also be easily created by retrofitting or converting an existing inlet nozzle with a suitably designed projection. Tests and simulations have shown that with an intake tract according to the invention, sufficient crankcase ventilation can be achieved even at low engine speeds and low mass flow rates through the exhaust gas turbocharger. The improved ventilation reduces the so-called reverse blow-by effect.largely eliminated, resulting in lower oil consumption and a reduction in particulate emissions.

[0012] If the projection, viewed in the direction of fresh air flow, has a maximum penetration depth into the fresh air duct in a forward longitudinal section of the inlet nozzle, the projection preferably has a maximum penetration depth at least in the region of the forward half of the length LE of the inlet nozzle, more preferably at least in the region of the forward third, and most preferably in the region of the first quarter. In other words, the flow cross-section of the fresh air duct is most reduced in a forward longitudinal section of the inlet nozzle due to the projection, so that an increased negative pressure is generated by the increase in the flow velocity in a region further downstream in the direction of flow, i.e., still within the length LE of the inlet nozzle.

[0013] The negative pressure in the blow-by gas channel of an intake tract according to the invention can be further increased if the projection – viewed in the direction of fresh air flow – already has a maximum penetration depth into the fresh air channel at the upstream beginning of the inlet nozzle. This causes the fresh air to flow through the opening at an increased velocity at the beginning of the inlet nozzle's length, generating the desired increased negative pressure starting at the upstream beginning of the inlet nozzle.

[0014] Further simulation calculations determined that efficient crankcase ventilation is achieved over a particularly large engine speed range when the inlet nozzle extends over a length L1 starting with a maximum insertion depth E maxa projection with an edge oriented in the main flow direction and projecting into the fresh air duct, wherein the length L1 extends over more than 30% of the length LE of the inlet nozzle. Preferably, the length L1 extends over more than 40%, particularly preferably over more than 50%, and further preferably over more than 60% of the length of the inlet nozzle LE.

[0015] Alternatively or additionally, it is preferred that the projection with length L1 extends, viewed transversely to the flow direction of the fresh gas, over at least 60% of the (maximum) width and particularly preferably over 100% of the width of the inlet nozzle. With respect to the width of the fresh air duct, the width of the projection may extend only over a portion of the width, in particular only over approximately 30%, approximately 40%, or approximately 50%. If the inlet nozzle has a circular cross-sectional geometry and the projection is intended to extend over 100% of the width of the inlet nozzle as an extension of a circular pipe wall projecting into the fresh air duct at the upstream beginning of the inlet nozzle, the projection must necessarily also extend over at least 50% of the length LE of the inlet nozzle.

[0016] In another practical embodiment, the inlet nozzle has a stepless transition at its downstream end to the wall of the fresh air duct that adjoins it in the direction of fresh air flow. This means that the insertion depth of the projection is zero at the latest at the downstream end of the inlet nozzle. By means of a stepless transition, flow turbulence of the fresh gas at the end of the inlet nozzle, which is associated with efficiency losses, is effectively avoided, thereby improving the efficiency with regard to vacuum generation.

[0017] Alternatively or additionally, it is advantageous if, in the case of an inlet nozzle viewed in the direction of fresh air flow, downstream of a longitudinal section with maximum penetration depth E maxThe penetration depth of the projection into the fresh air duct is designed to decrease continuously. In this context, it has proven particularly advantageous from both a manufacturing and efficiency perspective if the penetration depth decreases linearly from a maximum depth. This geometric design also avoids the formation of (especially significant) flow turbulence in the fresh air. It is particularly preferred if the penetration depth decreases continuously in such a way that it is zero before or at the latest at the downstream end, thus achieving a stepless transition to the fresh air duct.

[0018] As already mentioned, in a particularly simple design, the projection on the inlet nozzle is formed by an extended pipe wall of the blow-by gas channel projecting into the fresh air duct. In this case, the projection can be achieved by simply adapting a tool, in particular an injection mold for manufacturing a blow-by gas channel from plastic.

[0019] In another practical embodiment, the projection extends over a length LV of at least 40% of the length LE of the inlet nozzle. With projections designed in this way, particularly good efficiencies have been achieved over a wide speed range of the internal combustion engine, especially at low speeds below 2000 rpm. These results were primarily obtained in conjunction with embodiments in which the projection begins at the upstream end of the inlet nozzle and has a continuous, and in particular linearly decreasing, penetration depth in the region of a downstream end of the inlet nozzle. It is particularly preferred if the projection extends over at least 50%, at least 60%, more preferably at least 70%, and further preferably more than 80% or even more than 90% of the length LE of the inlet nozzle.

[0020] The intention is to use the intake tract according to the invention to reduce the efficiency of the compressor only minimally or not at all (i.e., by a maximum of 10%, a maximum of 5%, or considerably less) while simultaneously generating increased negative pressure. To achieve this, the maximum penetration depth of the at least one projection is preferably a maximum of 20%, more preferably a maximum of 18%, and further preferably a maximum of 16% of the maximum width or diameter of the fresh air duct. Alternatively or additionally, the change in compressor efficiency can also be determined directly. In this case, it is preferred that the flow cross-section for the fresh air is reduced by a maximum of 5% due to the projection, more preferably by a maximum of 4%, more preferably by a maximum of 3%, and particularly preferably by a maximum of 2% or only a maximum of 1%.

[0021] Further practical embodiments of the invention are described below in connection with the drawings. They show: Fig. 1. An intake manifold in a schematic representation, Fig. 2 the in Fig. 1 Part of the intake tract marked with II according to a first embodiment of an inlet nozzle with a projection in a sectional view, Fig. 3 the section of the intake tract marked II according to the first embodiment of the inlet nozzle with projection in a view in the direction of flow through the fresh air duct upstream of the inlet nozzle, Fig. 4 a second embodiment of only an inlet nozzle with a projection in a side view, Fig. 5 a third embodiment of an inlet nozzle with a projection in a side view, and Fig. 6 a fourth embodiment of an inlet nozzle with a projection in a side view.

[0022] In Fig. Figure 1 schematically shows an intake tract 10 according to the invention. The intake tract 10 comprises a fresh air duct 12 through which fresh air flows in the direction of arrow F to a compressor 14. The compressor 14 is part of a turbocharger (not shown). Upstream of the compressor 14, a blow-by gas duct 18 opens at a discharge point 16, through which blow-by gas from a crankcase (not shown) can be conveyed into the fresh air duct 12 in the direction of arrow B.

[0023] In Fig. Figure 2 shows the intake tract 10 in detail in the region of the outlet 16. Fresh air flows in the direction of arrow F through the fresh air duct 12 to the compressor 14. Perpendicular to the flow direction F of the air flowing through the fresh air duct 12, blow-by gas can flow in the direction of arrow B through the blow-by gas duct 18 to an outlet 16 and enter the fresh air duct 12 at this outlet 16. In the embodiment shown, both the blow-by gas duct 18 and the fresh air duct 12 are designed as pipes with a circular cross-section, i.e., the ducts 12 and 18 each have a circular inner cross-section and a circular outer cross-section. In the embodiment shown, the inner diameter of the fresh air duct 12 in the region of the outlet 16 is approximately twice the inner diameter of the blow-by gas duct 18.

[0024] As from the Fig. 2 and Fig. As can be clearly seen in Figure 3, the blow-by gas duct 18 has an inlet nozzle 20 in the area of ​​the outlet 16, on which a projection 22 is formed that extends into the flow cross-section of the fresh air duct 12. The projection 22 is designed as an extension of the pipe wall 24 of the blow-by gas duct. The projection 22 reduces the flow cross-section of the fresh air duct 12 over the length LV of the projection 22 compared to the area of ​​the fresh air duct 12 immediately upstream of the projection 22. The projection 22, with length LV, extends from an upstream beginning 26 of the inlet nozzle 20, viewed in the direction of fresh air flow F, over a portion of the length LE of the inlet nozzle 20, here approximately 45% of the length LE of the inlet nozzle 20. The penetration depth of the projection 22 decreases from a maximum penetration depth E. maxat the upstream beginning 26 of the inlet nozzle 20 continuously and linearly to zero.

[0025] The fresh air duct 12 has a conical shape in the area of ​​the outlet 16, with a diameter decreasing in the direction of flow according to arrow F. The maximum penetration depth E max The projection 22 at the upstream beginning 26 of the inlet nozzle 20 is approximately 20% of the diameter of the fresh air duct 12.

[0026] In Fig. Figure 3 shows a view into the fresh air duct 12 in the flow direction F upstream of the outlet 16. Viewed perpendicular to the flow direction F, the projection 22 extends over part of the width BE of the inlet nozzle 20. The width increases with the length of the projection 22 from the upstream beginning 26 of the inlet nozzle 20 to approximately 90% of the width of the inlet nozzle 20. This width corresponds to the width in the region of length LV, measured from the upstream beginning 26 of the inlet nozzle 20.

[0027] As in Fig. As can be clearly seen, the inlet nozzle 20 at the downstream end has a stepless transition to a wall 30 of the fresh air duct 12 adjoining it in the direction of flow.

[0028] In the Fig. Figures 4 to 6 show only the respective inlet nozzles 20 with projection 22 of further embodiments of the intake tracts 10 according to the invention. For the description of these embodiments, the same reference numerals are used below for identical or at least functionally equivalent elements as for the description of the first variant.

[0029] In the Fig. In the second embodiment of an inlet nozzle 20 shown in section 4, the projection 22 has a length L1 beginning with a maximum insertion depth E. max At the upstream beginning 26, a projection 22 with an edge oriented in the main flow direction and projecting into the fresh air duct 12 is present. The entire projection 22 extends over the length LV, which corresponds to the total length LE of the inlet nozzle 20. L1 is 50% of the length LE, or the length LV. Starting from the upstream beginning 26 of the inlet nozzle 20 with the maximum insertion depth E maxThe penetration depth decreases continuously and linearly in two sections towards the downstream end 28 of the inlet nozzle 20, first over the length L1, then over the remaining length. The reduction in penetration depth in the region of length L1 results from the conical design of the fresh air duct 12, as shown from Fig. 2 is evident.

[0030] The third in Fig. The fifth depicted variant of an inlet nozzle 20 has a projection 22 extending over a length LV that also corresponds to the total length LE of the inlet nozzle 20. The projection 22 initially extends with an edge parallel to the main flow direction F from the upstream end 26 of the inlet nozzle 20 over a length L1. Subsequently, the penetration depth decreases more sharply and linearly until it is reduced to zero at the downstream end 28 of the inlet nozzle 20. In contrast to the second embodiment, the length L1 of the longitudinal section in the third embodiment is 75% of the length LV of the projection 22, or the length LE of the inlet nozzle 20.

[0031] The in Fig. The fourth embodiment of an inlet nozzle 20, as shown in Figure 6, also has a projection 22 which reaches its maximum insertion depth E at the upstream beginning 26 of the inlet nozzle 20. maxThe projection 22 extends initially over the length LV with an edge parallel to the main airflow direction as indicated by arrow F. At the end of length LV, a stepped shoulder is provided on the projection 22 such that the penetration depth is minimal and decreases to zero at the downstream end 28 of the inlet nozzle 20, taking into account the conical internal geometry of the fresh air duct 12 in the region of the outlet 16. This again creates a step-free transition of the flow from the inlet nozzle 20 to the wall of the fresh air duct 12, which follows the flow direction F. Since the penetration depth in the region after length L1 is minimal and is assumed to have practically no effect, length L1 was considered the length LV of the projection 22 in this embodiment.

[0032] The features of the invention disclosed in the present description, the drawings, and the claims can be essential for realizing the invention in its various embodiments, both individually and in any combination. The invention can be varied within the scope of the claims and taking into account the knowledge of the person skilled in the art. In particular, the maximum insertion depth E can be varied. max as well as the ratios of the lengths LE, LV and L1 can be varied as needed. Reference symbol list 10 Intake tract 12 Fresh air duct 14 compressors 16 Mouth 18 Blow-by gas channel 20 inlet nozzles 22 lead 24 pipe wall 26 upstream start 28 downstream end 30 Wall of the fresh air duct E max maximum insertion depth LE Length of the inlet nozzle LV Length of the lead L1 Length of the section with E max

Claims

[1] Intake manifold of an internal combustion engine with a blow-by gas channel (18) for returning blow-by gas from a crankcase to a fresh air channel (12) of an intake manifold (10) upstream of a compressor (14), wherein the blow-by gas channel (18) has an inlet nozzle (20) in the region of an outlet (16) of the blow-by gas channel (18) into the fresh air channel (12), wherein the inlet nozzle (20) has at least one projection (22) with a length LV projecting into the flow cross-section of the fresh air channel (12), which reduces the flow cross-section available for the fresh air at least in a longitudinal section extending over a part of the length LE of the inlet nozzle (20) compared to the area of ​​the fresh air channel (12) immediately upstream of the projection (22), characterized by , that a) the projection (22) with length LV extends from an upstream beginning (26) of the inlet nozzle (20) in the flow direction F of the fresh air over a part of the length LE of the inlet nozzle (20) and the penetration depth of the projection (22) decreases continuously and linearly to zero from a maximum penetration depth Emax at the upstream beginning (26) of the inlet nozzle (20) or b) the projection (22) extends over a length L1 starting with a maximum penetration depth Emax at the upstream beginning (26) and the penetration depth is constant over the length L1 and the penetration depth of the projection (22) decreases continuously and linearly to zero downstream of the length L1. [2] Intake tract according to variant b) of the preceding claim, characterized by , that the length L1 extends over more than 30 percent of the length LE of the inlet nozzle (20). [3] Intake tract according to one of the preceding claims, characterized by , that the inlet nozzle (20) at the downstream end (28) has a stepless transition to the wall (30) of the fresh air duct (12) which adjoins it in the direction of flow of the fresh air. [4] Intake tract according to one of the preceding claims, characterized by , that, viewed in the direction of flow of fresh air, downstream of a longitudinal section with maximum penetration depth (E max ) into the fresh air duct (12) the penetration depth of the projection (22) is continuously decreasing. [5] Intake tract according to one of the preceding claims, characterized by , that the projection (22) on the inlet nozzle (20) is formed in the form of an extended pipe wall (24) of the blow-by gas channel (18) projecting into the fresh air duct (12). [6] Intake tract according to one of the preceding claims, characterized by, that the projection (22) extends over a length LV which is at least 40 percent of the length LE of the inlet nozzle (20). [7] Intake tract according to one of the preceding claims, characterized by , that the maximum insertion depth (E max ) of at least one projection (22) is a maximum of 20 percent of the diameter and / or that the flow cross-section for the fresh air through the projection (22) is reduced by a maximum of 5 percent.

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