DE102016214074A1 - Intake tract of an internal combustion engine with a blow-by gas channel for the return of blow-by gas from a crankcase in a fresh air duct - Google Patents

Abstract

The invention relates to an intake system of an internal combustion engine with a blow-by gas channel (18) for returning blow-by gas from a crankcase in a fresh air duct (12) of an intake (10) upstream of a compressor (14), wherein Blow-by gas channel (18) in the region of the opening point (16) to the fresh air duct (12) has an inlet connection (20), wherein the inlet connection (20) at least one, in the flow cross-section of the fresh air channel (12) protruding projection (22 ) having a length LV which reduces the flow cross section available for the fresh air at least in a portion extending over part of the length LE of the inlet nozzle (20) relative to the region of the fresh air channel (12) adjoining immediately upstream of the projection (22) ,

Description

The invention relates to an intake tract of an internal combustion engine with a blow-by gas channel for returning blow-by gas from a crankcase into a fresh air duct according to the preamble of claim 1. In particular, the invention relates to the structural design of a mouth of a blow-by -Gas channel in a fresh air duct, preferably for internal combustion engines of motor vehicles.

When supercharged by exhaust gas turbochargers engines negative pressure for the venting of the crankcase of an internal combustion engine is generated in particular using the intake of the exhaust gas turbocharger in front of the compressor. At low engine speeds, especially in the range below 2000 rev / min, in a supercharged engine operation and thus a low exhaust gas turbocharger speed or a low mass flow of fresh gas through the exhaust gas turbocharger may not be sufficient vacuum to vent the crankcase or a sufficient blow -By actively promote gas from the crankcase.

Out DE 10 2015 008 291 A1 For example, a method for operating an internal combustion engine with an intake tract and a compressor of an exhaust gas turbocharger is known. By means of a return device, at least part of the compressed air downstream of the compressor can be branched off, returned and introduced again into the intake tract at a feed point upstream of the compressor. It is also described to direct the recirculated compressed air to the feed point via a Venturi nozzle to generate a negative pressure to effect crankcase ventilation by means of the branched air.

Out DE 10 2010 029 150 A1 For example, a system for a variable venturi engine is known which is intended to include a slidable "egg" and coupled into an inlet of the engine. In addition, reference is made to vacuum generating devices which may be provided in addition.

The invention has for its object to provide an intake tract of an internal combustion engine available, with which a simple way, a crankcase can be vented efficiently.

The object is achieved according to the invention by the features of claim 1. Further practical embodiments and advantages of the invention are described in connection with the dependent claims.

An inventive intake tract of an internal combustion engine comprises a blow-by gas passage for returning blow-by gas from a crankcase into a fresh air passage upstream of a compressor, the compressor being part of an exhaust gas turbocharger. The blow-by gas channel has in the region of an opening point of the blow-by gas channel in the fresh air duct to an inlet. The inlet connection piece furthermore has at least one projection projecting into the flow cross-section of the fresh air channel and having a length LV which adjoins the flow cross-section available for the fresh air, at least in a longitudinal section extending over part of the length LE of the inlet connection piece, in relation to that immediately upstream of the projection Area of the fresh air duct reduced. The orientation of the above indicated lengths corresponds to the main flow direction of the air flowing through the fresh air passage, i. the longitudinal extension direction of the fresh air duct in the region of the inlet.

By the formation of at least one protrusion with the length LV at the inlet pipe extending over part of the length of the inlet nozzle LE as described above, an additional negative pressure is generated in the blow-by-gas channel in a simple manner and the pumping of blown gas is achieved. Improved by gas from the crankcase, because by the projection caused (preferably only small) cross-sectional reduction, the flow velocity in the fresh air duct is locally increased, whereby an additional negative pressure in the blow-by gas channel is generated. It is particularly advantageous that an inventive intake tract can be realized by simple geometric adjustment of the inlet pipe almost no additional cost and without additional space requirements.

As a projection in the context of the invention, any area provided or formed in the area of the inlet nozzle is considered, which extends from the inlet nozzle transversely to the main flow direction through the fresh air channel into the fresh air channel and thus acts cross-section reducing. The formation or arrangement of such a projection on the inlet connection can be realized in a particularly simple and cost-effective manner by a projecting arrangement and suitable design of the pipe end of a tubular inlet connection.

The intake manifold according to the invention can be implemented not only simple and inexpensive, but is also a robust and durable construction for permanent improvement of the crankcase ventilation. It is also advantageous that a constructive change of the fresh air duct for the realization of the invention is not required is. An inventive intake tract can also be created simply by retrofitting or retrofitting by replacing an existing inlet nozzle with a suitably designed projection. Through experiments and simulation calculations it was found that with an intake tract according to the invention a sufficient ventilation of the crankcase can be achieved even at low engine speeds and low mass flow through the exhaust gas turbocharger. Due to the improved venting, the so-called reverse-blow-by effect is reduced or largely eliminated, resulting in lower oil consumption and a reduction in particulate emissions.

In a particularly efficient embodiment, the projection in the flow direction of the fresh air viewed in a front longitudinal section of the inlet nozzle on a maximum Einragtiefe in the fresh air duct. In this case, the projection preferably has a maximum penetration depth at least in the region of the front half of the length LE of the inlet nozzle, more preferably at least in the region of the front third and particularly preferably in the region of the first quarter. In other words, in this case, the flow area of the fresh air passage is most reduced in a front length portion of the introduction port due to the protrusion, so that by increasing the flow rate in a downstream portion, i.e., the downstream direction. still within the length LE of the inlet, an increased negative pressure is generated.

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 flow of fresh air - already at the upstream beginning of the inlet nozzle has a maximum Einragtiefe in the fresh air duct. As a result, the fresh air already flows at the beginning of the length of the inlet nozzle with increased speed through the discharge point and generates the desired, increased negative pressure starting at the upstream beginning of the Einleitstutzes.

By further simulation calculations it was determined that an efficient ventilation of the crankcase over a particularly large speed range of the internal combustion engine is achieved when the inlet nozzle over a length L1 starting with a maximum Einragtiefe E _max a projection with an oriented in the main flow direction, projecting into the fresh air duct edge , 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%, more preferably over more than 50% and more preferably over more than 60% of the length of the inlet nozzle LE.

Alternatively or in addition to this, it is preferred if the projection with the length L1, viewed transversely to the flow direction of the fresh gas, extends over at least 60% of the (maximum) width and particularly preferably over 100% of the width of the inlet connecting piece. With respect to the width of the fresh air duct, the width of the protrusion may extend only over part of the width, in particular only over about 30%, about 40% or about 50%. If the inlet nozzle has a circular cross-sectional geometry and the projection is already at the upstream beginning of the inlet as extending into the fresh air duct extension of a circular cross-section pipe wall is to extend over 100% of the width of the inlet, the projection must inevitably over at least 50% extend the length LE of the inlet.

In a further practical embodiment, the inlet connection piece at the downstream end has a step-free transition to the wall of the fresh air channel adjoining in the flow direction of the fresh air. That is, the projection depth of the projection is zero at the latest at the downstream end of the inlet nozzle. By means of a step-free transition associated with efficiency losses flow turbulence of the fresh gas at the end of the Einleitstutzes be effectively avoided, whereby the efficiency with respect to the vacuum generation is improved.

Alternatively or additionally, it is advantageous if, viewed in the direction of flow of the fresh air, downstream of a longitudinal section having a maximum penetration depth E _max into the fresh air duct, the penetration depth of the projection is continuously decreasing. In this context, it has proven to be particularly advantageous both in terms of production technology and efficiency when the penetration depth is designed to decrease linearly starting from a maximum penetration depth. This geometric design also avoids the formation of (in particular larger) flow turbulences in the fresh gas. It is particularly preferred if the Einragtiefe is designed so continuously decreasing that it is zero before or at the latest at the downstream end, so that a stepless transition to the fresh air duct is realized.

As already indicated, the projection on the inlet connection piece is designed in a structurally particularly easily implementable embodiment in the form of an extended tube wall of the blow-by gas channel projecting into the fresh air channel. The projection can be realized in this case by a simple adaptation of a tool, in particular an injection molding tool for producing a blow-by gas channel made of plastic.

In a further 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 were achieved over a large speed range of the internal combustion engine, in particular even at low speeds of less than 2000 rpm. These results have been achieved mainly in connection with embodiments in which the projection begins at the upstream start of the inlet nozzle and has a continuous, in particular linearly decreasing, penetration depth in the area of a downstream end of the inlet nozzle. It is particularly preferred if the projection extends over at least 50%, at least 60%, particularly preferably at least 70%, and more preferably more than 80% or even more than 90% of the length LE of the inlet connecting piece.

It is intended that with the intake manifold according to the invention the efficiency of the compressor not or only slightly (i.e., not more than 10%, not more than 5% or significantly less) to reduce and simultaneously to generate an increased negative pressure. To achieve this, the maximum penetration depth of the at least one projection is preferably not more than 20%, more preferably not more than 18% and more preferably not more than 16% of the maximum width or diameter of the fresh air duct. Alternatively or in addition, the change in efficiency of the compressor can also be determined directly. In this case, it is preferable if the flow cross section for the fresh air is reduced by a maximum of 5% due to the projection, 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%.

In a further easily produced embodiment, viewed downstream of a length section with maximum entry depth into the fresh air duct, the entry depth of the projection can be formed in a stepwise decreasing manner in the direction of flow. In particular, the Einragtiefe can be formed over several stages or over a step decreasing.

Further practical embodiments of the invention are described below in conjunction with the drawings. Show it:

1 an intake tract in a schematic representation,

2 the in 1 II with part of the intake tract according to a first embodiment of a Einleitstutzens with a projection in a sectional view,

3 the section of the intake tract marked II in accordance with the first embodiment of the inlet nozzle with a projection in a view in the flow direction through the fresh air duct upstream of the inlet nozzle,

4 a second embodiment of only one Einleitstutzens with a projection in a side view,

5 a third embodiment of a Einleitstutzens with a projection in a side view, and

6 a fourth embodiment of a Einleitstutzens with a projection in a side view.

In 1 is an inventive intake tract 10 shown schematically. The intake tract 10 includes a fresh air duct 12 through which fresh air in the direction of arrow F to a compressor 14 flows. The compressor 14 is part of a turbocharger, not shown. Upstream of the compressor 14 flows at a confluence point 16 a blow-by gas channel 18 , by which blow-by gas from a crankcase (not shown) in the direction of arrow B in the fresh air duct 12 can be promoted.

In 2 is the intake tract 10 in the area of the estuary 16 shown in detail. 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 through the fresh air duct 12 flowing air can blow-by gas in the direction of arrow B through the blow-by gas channel 18 to an estuary 16 and at this confluence 16 in the fresh air channel 12 flow. In the embodiment shown, both the blow-by gas channel 18 as well as the fresh air channel 12 formed as tubes with a circular cross section, ie the channels 12 . 18 each have a circular inner cross section and a circular outer cross section. The inner diameter of the fresh air channel 12 is in the embodiment shown in the region of the mouth 16 about twice the inner diameter of the blow-by gas channel 18 ,

Like from the 2 and 3 is clearly evident, the blow-by gas channel 18 in the area of the estuary 16 an inlet pipe 20 on, at which a in the flow cross-section of the fresh air channel 12 protruding projection 22 is trained. The lead 22 is present as an extension of the pipe wall 24 formed of the blow-by gas channel. By the projection 22 becomes the flow area of the fresh air channel 12 about the length LV of the projection 22 compared to the immediately upstream of the projection 22 adjoining area of the fresh air duct 12 reduced. The lead 22 in the present case extends from an upstream beginning 26 the inlet pipe 20 in the flow direction F of the fresh air considered over a portion of the length LE of the inlet 20 , here about 45% of the length LE of the inlet 20 , The penetration depth of the projection 22 decreases starting from a maximum Einragtiefe E _max at the upstream beginning 26 the inlet pipe 20 continuous and linear to zero.

The fresh air duct 12 points in the area of the mouth 16 a conical shape with a decreasing in the flow direction according to the arrow F diameter. The maximum penetration depth E _{max of} the projection 22 is at the upstream beginning 26 the inlet pipe 20 about 20% of the diameter of the fresh air channel 12 ,

In 3 is a view into the fresh air duct 12 in the flow direction F upstream of the mouth 16 shown. Viewed transversely to the flow direction F is the projection 22 over a part of the width BE of the inlet 20 educated. The width decreases with increasing length of the projection 22 from the upstream beginning 26 the inlet pipe 20 to a total of about 90% of the width of the inlet 20 to. This width corresponds to the width in the region of the length LV, measured from the upstream beginning 26 the inlet pipe 20 ,

As in 2 is clearly visible, the inlet pipe 20 at the downstream end a stepless transition to a downstream wall in the flow direction 30 of the fresh air channel 12 on.

In the 4 to 6 are only the respective inlet pipe 20 with a lead 22 of further embodiments of inventive intake tracts 10 shown. For describing these embodiments, the same reference numerals will be used below for identical or at least functionally identical elements as for the description of the first variant.

In the in 4 shown second embodiment of a Einleitstutzens 20 has the lead 22 over a length L1 beginning with a maximum Einragtiefe E _max at the upstream beginning 26 a lead 22 with an oriented in the main flow direction, in the fresh air duct 12 protruding edge. The entire lead 22 extends over the length LV, that of the entire length LE of the inlet 20 equivalent. In the present case, L1 is 50% of the length LE, or the length LV. Starting from the upstream beginning 26 the inlet pipe 20 with the maximum penetration depth E _max , the penetration depth in two sections decreases continuously linearly in the direction of the downstream end 28 the inlet pipe 20 , first over the length L1, then over the remaining length. The reduction of the penetration depth in the region of the length L1 results from the conical design of the fresh air duct 12 , like out 2 seen.

The third in 5 illustrated variant of a Einleitstutzens 20 has a lead 22 extending over a length LV, which is also the entire length LE of the inlet 20 equivalent. In this case, the projection extends 22 first with an edge parallel to the main flow direction F seen from the upstream beginning 26 the inlet pipe 20 over the length L1. Subsequently, the insertion depth decreases more strongly and linearly so as to reach the downstream end 28 the inlet pipe 20 is reduced to zero. In contrast to the second embodiment, the length L1 of the length portion in the third embodiment is 75% of the length LV of the protrusion 22 or the length LE of the inlet nozzle 20 ,

In the 6 illustrated fourth embodiment of a Einleitstutzens 20 also has a lead 22 on, at the upstream beginning 26 the inlet pipe 20 has its maximum Einragtiefe E _max . The lead 22 in turn extends first over the length LV with an edge parallel to the main flow direction of the air according to the arrow F. At the end of the length LV is a stepped shoulder on the projection 22 provided such that the Einragtiefe is only minimal and to the downstream end 28 the inlet pipe 20 taking into account the conical internal geometry of the fresh air duct 12 in the area of the estuary 16 drops to zero. It is in turn a step-free transition of the flow of the inlet pipe 20 on the adjoining in the flow direction F wall of the fresh air duct 12 realized. Since the penetration depth in the region along the length L1 is only minimal and it is considered that it has practically no effect, in the embodiment, the length L1 became the length LV of the projection 22 considered.

The features of the invention disclosed in the present description, in the drawings and in the claims may be essential both individually and in any desired combinations for the realization of the invention in its various embodiments. The invention may be varied within the scope of the claims and in consideration of the knowledge of the person skilled in the art. Thus, in particular, the maximum penetration depth E _max and the ratios of the lengths LE, LV and L1 can be varied as required.

LIST OF REFERENCE NUMBERS

10

intake system

12

Fresh air duct

14

compressor

16

opening point

18

Blow-by gas channel

20

feed connection

22

head Start

24

pipe wall

26

upstream start

28

downstream end

30

Wall of fresh air channel

E _max

maximum landing depth

LE

Length of the inlet

LV

Length of the projection

L1

Length of section with E _max

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102015008291 A1 [0003]
• DE 102010029150 A1 [0004]

Claims (10)

Intake tract of an internal combustion engine with a blow-by gas channel ( 18 ) for returning blow-by gas from a crankcase into a fresh air duct ( 12 ) of an intake tract ( 10 ) upstream of a compressor ( 14 ), wherein the blow-by gas channel ( 18 ) in the area of a confluence point ( 16 ) of the blow-by gas channel ( 18 ) in the fresh air channel ( 12 ) an inlet nozzle ( 20 ), characterized in that the inlet nozzle ( 20 ) at least one, in the flow cross-section of the fresh air channel ( 12 protruding projection ( 22 ) having a length LV, which defines the flow cross-section available for the fresh air at least in one, over a part of the length LE of the inlet ( 20 ) extending longitudinal portion opposite to immediately upstream of the projection ( 22 ) adjoining region of the fresh air channel ( 12 ) decreased. Intake tract according to the preceding claim, characterized in that the projection ( 22 ) viewed in the flow direction of the fresh air in a front longitudinal section of the inlet ( 20 ) a maximum Einragtiefe (E _max ) in the fresh air channel ( 12 ) having. Intake tract according to the preceding claim, characterized in that the projection ( 22 ) in the flow direction of the fresh air at the upstream beginning ( 26 ) of the inlet ( 20 ) a maximum Einragtiefe (E _max ) in the fresh air channel ( 12 ) having. Intake tract according to one of the preceding claims, characterized in that the inlet nozzle ( 20 ) over a length L1 starting with a maximum insertion depth (E _max ) a projection ( 22 ) oriented in the main flow direction, in the fresh air channel ( 12 ), wherein the length L1 over more than 30 percent of the length LE of the inlet ( 20 ). Intake tract according to one of the preceding claims, characterized in that the inlet nozzle ( 20 ) at the downstream end ( 28 ) a stepless transition to the adjoining in the flow direction of the fresh air wall ( 30 ) of the fresh air channel ( 12 ) having. Intake tract according to one of the preceding claims, characterized in that, viewed in the flow direction of the fresh air, downstream of a longitudinal section with maximum insertion depth (E _max ) into the fresh air channel ( 12 ) the insertion depth of the projection ( 22 ) is formed continuously decreasing. Intake tract according to one of the preceding claims, characterized in that the projection ( 22 ) at the inlet nozzle ( 20 ) in the form of a prolonged, in the fresh air channel ( 12 ) projecting pipe wall ( 24 ) of the blow-by gas channel ( 18 ) is trained. Intake tract according to one of the preceding claims, characterized in that the projection ( 22 ) extends over a length LV which is at least 40 percent of the length LE of the inlet ( 20 ) corresponds. Intake tract according to one of the preceding claims, characterized in that the maximum penetration depth (E _max ) of the at least one projection ( 22 ) is at most 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. Intake tract according to one of the preceding claims, characterized in that, viewed in the flow direction, downstream of a longitudinal section with maximum insertion depth (E _max ) into the fresh air channel ( 12 ) the insertion depth of the projection ( 22 ) be formed stepwise decreasing.

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