DE102012015290A1 - Combustion engine for driving motor car, has nozzle with flow portion that is connected with specific terminal section in fluid-conductive manner, such that flow direction of intake air from compressor is opened into intake manifold - Google Patents

Abstract

The combustion engine (1) has nozzles (11,12) having flow portions (15,16) that are arranged coaxially in flow axis (sa). The flow portion (15) is connected with a terminal section (21) in fluid-conductive manner, such that the flow direction of intake air from a compressor (7) is opened into an intake manifold (2) in upstream. The flow portion (16) is connected with a terminal section (22) in fluid-conductive manner, such that the flow direction of intake air is opened in the intake manifold between the downstream of a throttle cap (24) and combustion engine.

Description

The invention relates to an internal combustion engine with a vacuum generating system for motor vehicles, wherein the vacuum generating system has a nozzle operating according to the Bernoulli effect.

Such a vacuum generating system is from the document US 2009/0132149 A1 known. A jet pump is bypassed around a throttle. Gas flowing through the jet pump is used to generate a negative pressure. The negative pressure can, for example, drive a brake booster.

An object of the invention is to provide a supercharged vacuum generating system capable of generating the negative pressure for the vacuum reservoir even with an overpressure in the intake tract.

This object is solved by the features of patent claim 1. Further advantageous embodiments of the invention are each the subject of the dependent claims. These can be combined in a technologically meaningful way. The description, in particular in conjunction with the drawing, additionally characterizes and specifies the invention.

Accordingly, there is provided an internal combustion engine having a vacuum generating system for a motor vehicle, comprising a Bernoulli effect nozzle for generating a vacuum, the nozzle having two flow portions coaxial with a flow axis and one orthogonal to the nozzle at a narrowest cross section between the flow portions A conduit portion, wherein the conduit portion is fluidly connected to a vacuum chamber, and wherein a first flow portion is fluidly connected to a first port portion which opens in the intake air flow direction upstream of a compressor in an intake tract, and wherein a second flow portion fluidly communicating with a second connection portion is connected, which opens between in the intake air flow direction downstream of a throttle cap and an internal combustion engine in the intake.

The generated vacuum can be used, for example, in a brake booster and / or in negative pressure operated actuators and actuators. The compressor may be the compressor of a turbocharger, a compressor or similar device for compressing or sucking in aspirated air. A gas stream conducted through the nozzle is used to generate negative pressure. In this case, the operating according to the Bernoulli effect nozzle is connected in the intake manifold, that in some operating points of the compressor generated overpressure is used to generate the gas flow, namely at relatively wide-opened throttle. An additional vacuum pump for generating the necessary vacuum for the brake booster can be omitted if necessary or be dimensioned smaller.

In one embodiment, the first connection section opens into the intake tract downstream of an air mass meter.

The air mass meter detects a volume flow of sucked air. From this, a correct air-fuel ratio is calculated. By arranging the air mass meter upstream of the first connecting line, the measurement result is not falsified by the intake air being taken off.

In one embodiment, the nozzle is designed as a jet pump.

Jet pumps are relatively simple. From the air flow, a relatively large negative pressure can be generated.

In a further embodiment, the vacuum generating system has a second nozzle arranged parallel to the first nozzle.

In this embodiment, the first nozzle generates a negative pressure with only slightly open throttle, for example, at idle. In this first operating point prevails between the first connection portion and the second connection portion, a pressure gradient, d. H. the pressure at the first connection section is greater than at the second connection section. At the first connection section in front of the turbocharger, there is almost ambient pressure in this operating state. At the second connection portion downstream of the throttle valve, there is a negative pressure. Intake air flows according to the pressure gradient through the first nozzle from the first connection portion to the second connection portion and generates by the Bernoulli effect a negative pressure, which can be used by the brake booster.

At operating points in which the throttle cap is wide open, there is a pressure increase, ie, that the pressure downstream of the throttle cap and thus at the second connection portion due to the charging of the intake air is greater than before the compressor at the first connection portion. Air now flows in the reverse direction according to the pressure increase from the second connection section through the second nozzle into the first connection section. By the Bernoulli effect can also in this operating state, a vacuum can be generated.

According to a further embodiment, the vacuum generating system on check valves, which are arranged so that either the first nozzle or the second nozzle is flowed through.

The check valves allow either a flow through the first nozzle or the second nozzle, depending on whether there is a pressure gradient or an increase in pressure. It can be used by a matched to the respective flow direction nozzle.

In a further embodiment, the vacuum generating system has a switching valve for switching off the nozzle.

When considered negative in the negative pressure in the brake booster can be closed via the switching valve of the bypass to avoid boost pressure losses.

According to one embodiment, the vacuum generating device described herein may be integrated into a molded part, which has a connection for connection to the first connection section and a connection for connection to the second connection section. A third connection can be provided in the molded part for the fluid-conducting connection to the vacuum reservoir or the brake booster.

The molded part can be made in one piece and contain all parts of the vacuum generating system. Thereby, the assembly of the vacuum generating system can be simplified.

Some embodiments will be explained in more detail with reference to the drawing. Show it:

1 schematically a combustion engine, its intake and exhaust tract and a brake booster, which is supplied via two counter-rotating Venturi nozzles with a negative pressure,

2 : schematically the internal combustion engine off 1 , wherein the brake booster is supplied via two counter-rotating jet pumps with a negative pressure, and

3 : schematically the combustion engine from the 1 and 2 , wherein the brake booster is supplied via a single bi-directional Venturi nozzle with a negative pressure.

In the figures, identical or functionally identical components are provided with the same reference numerals.

1 shows an internal combustion engine 1 with an intake tract 2 and an exhaust tract 3 , Through the intake tract 2 becomes the internal combustion engine 1 Supplied with air. The intake tract 2 extends from an air filter 4 up to the combustion engine 1 , In operation, exhaust gas from the internal combustion engine 1 through a turbine 5 a turbocharger 6 directed. The turbine 6 drives a compressor 7 at. The compressor 7 compresses the intake air.

The internal combustion engine 1 can be used to drive an otherwise not shown motor vehicle. The motor vehicle can be braked via a brake system, also not shown. To assist the driver in applying the necessary braking force, the motor vehicle also has a brake booster 8th on. The brake booster 8th uses a pressure difference between a vacuum chamber 9 and a second chamber 10 , which can be subjected to ambient pressure to increase the braking force. In the vacuum chamber 9 This is a vacuum or vacuum required. The vacuum is passed through a vacuum generating system 14 generated. The vacuum generating system has a first nozzle 11 and a second nozzle 12 on and check valves 13 , The check valves 13 are arranged so that only one nozzle at a time 11 or 12 is flowed through.

The nozzles 11 and 12 have flow sections arranged on a flow axis sa 15 and 18 respectively. 17 and 16 on.

A first flow section 15 the first nozzle 11 is fluid-conducting with a first connection section 21 connected. The first connection section 21 is fluid-conducting with a section 20 of the intake tract 2 connected. The section 20 is in the intake air flow direction S downstream of an air mass meter 19 and in front of the compressor 7 , By the intake air flow direction S is meant a flow of sucked air which is substantially parallel to the respective tubular members through which the air is passed. For example, the air can be connected to the compressor 7 can be redirected. In many operating points of the internal combustion engine 1 or the turbocharger 6 prevails in the section 20 Atmospheric pressure or a slight negative pressure, which is due to the fact that air through the air filter 4 as well as at the air mass meter 19 must be sucked over (if necessary, depending on the engine concept, the air mass meter 19 omitted).

The second flow section 16 the first nozzle 11 is fluid-conducting with a check valve 13 connected, in such a way that air from the nozzle 11 through the check valve 13 in a second connection section 22 can flow. The second connection section 22 is with a section 23 of the intake tract 2 fluidly connected. The section 23 is in the intake air flow direction S downstream of a throttle valve 24 and upstream of the engine 1 , For example, in a quantity-controlled internal combustion engine 1 gets over the throttle 24 regulated a volume flow of sucked air. This can be the throttle 24 be pivoted until it opposes the air almost no resistance. The use of a pressure drop for generating a negative pressure in the manner described herein is also possible in a quality-controlled internal combustion engine without throttle. In many operating points, for example, when idling or in overrun operation of the internal combustion engine 1 is the throttle 24 only partially open. In the intake air flow direction S downstream of the throttle valve 24 prevails in these operating points, a negative pressure, which is due to the fact that the internal combustion engine 1 Air sucks. Accordingly, the pressure applied to the first port portion 21 is present, at these operating points greater than at the second connection section 22 , Accordingly acts on the vacuum generation system 14 a pressure gradient, which is an air flow through the first nozzle 11 promotes. The second nozzle 12 is not flowed through, as connected in series with the second nozzle check valve 13 is kept closed at the prevailing pressure gradient.

At a narrowest cross-section 25 the airflow is accelerated. As a result, the pressure in the air drops locally. In the area of the narrowest cross-section 25 is a line section 26 arranged, which in the vacuum chamber 9 of the brake booster 8th empties. One in the line section 26 arranged check valve 13 ensures that no air in the reverse direction in the brake booster 8th can get.

At operating points in which the throttle 24 is wide open and the compressor 7 works, is the pressure in the second connection section 22 higher than in the first connection section 21 , Accordingly, the vacuum generation system prevails 14 a pressure increase. The second nozzle 12 Now air is flowed through. The second nozzle 12 is also designed as a Venturi nozzle. At its narrowest cross section 25 is also a line section 26 connected. The second line section 26 also opens into the brake booster 8th , Thus, it always works even when the compressor is working 7 used an air flow to a vacuum in the brake booster 8th to create.

2 shows an alternative embodiment, in which counter-switched, as jet pumps 31 and 32 designed nozzles 11 and 12 be used to generate a negative pressure. A first jet pump 31 is fluid-conducting with the first connection section 21 connected. A check valve 13 is switched so that the first jet pump 31 at pressure gradient between the first connection section 21 and the second terminal portion 22 is flowed through. Another check valve 13 is a second jet pump 32 assigned. This check valve 13 is closed at the prevailing pressure gradient. If there is a pressure increase, this is the first jet pump 31 associated check valve 13 closed and one of the second jet pump 32 associated check valve 13 open. Analogous to the above-described operation, by utilizing an air flow, a negative pressure for the brake booster 8th generated.

3 shows a further embodiment, which only one nozzle 11 has, which is designed as a venturi. The nozzle 11 can be traversed in both directions by an air flow. The nozzle 11 generated at a narrowest cross-section 25 a negative pressure by accelerating the air flow. One of the narrowest cross section 25 arranged line section 25 connects the nozzle 11 fluid-conducting with the brake booster 8th , To reverse the flow of air through the pipe section 26 to prevent is in the line section 26 a check valve 13 arranged. The nozzle 11 can be constructed and dimensioned so that an exploitation of the gas flows is ensured in both directions.

The in the 1 to 3 illustrated nozzles 11 and 12 can via a normally open switching valve 33 be actively interrupted when the negative pressure in the brake booster 8th considered sufficient to bypass the compressor 7 to avoid.

The nozzles 11 and 12 as well as the switching valve 33 and the check valves 13 are in a dashed illustrated molding 34 integrated, which is a first connection 35 for connection to the first connection section 21 and a second connection 36 for connection to the second connection section 22 as well as a third connection 37 for connecting a brake booster 8th having.

Although some possible embodiments of the invention have been disclosed in the foregoing description, it is understood that Numerous other variants of embodiments by combination options of all mentioned and further all obvious to those skilled in technical features and embodiments exist. It is further understood that the embodiments are to be understood as examples only, which in no way limit the scope, applicability and configuration. Rather, the foregoing description would suggest a suitable way for the skilled person to realize at least one exemplary embodiment. It should be understood that in an exemplary embodiment, numerous changes in the function and arrangement of the elements may be made without departing from the scope and equivalents disclosed in the claims.

LIST OF REFERENCE NUMBERS

1

internal combustion engine

2

intake system

3

exhaust tract

4

air filter

5

turbine

6

turbocharger

7

compressor

8th

Brake booster

9

Vacuum chamber

10

second chamber

11

first nozzle

12

second nozzle

13

check valve

14

Vacuum induction system

15

first flow section

16

second flow section

17

first flow section

18

second flow section

19

Air flow sensor

20

Section in front of turbocharger

21

first connection section

22

second connection section

23

Section downstream of throttle

24

throttle

25

closest cross section

26

line section

31

first jet pump

32

second jet pump

33

switching valve

34

molding

35

first connection

36

second connection

37 third

connection

S

Intake air flow direction

Sat.

flow axis

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

• US 2009/0132149 A1 [0002]

Claims (8)

Internal combustion engine ( 1 ) with a vacuum generating system for a motor vehicle, comprising a Bernoulli effect nozzle ( 11 . 12 ) for generating a vacuum, wherein the nozzle ( 11 . 12 ) two coaxial with a flow axis (sa) lying flow sections ( 15 . 16 ) and one at a narrowest cross section ( 25 ) between the flow sections ( 15 . 16 ) orthogonal to the nozzle ( 11 . 12 ) section ( 26 ), wherein the line section ( 26 ) fluid-conducting with a vacuum chamber ( 9 ), and wherein a first flow section ( 15 ) fluid-conducting with a first connection section ( 21 ) in the intake air flow direction (S) upstream of a compressor ( 7 ) into an intake tract ( 2 ), and wherein a second flow section ( 16 ) fluidly with a second connection section ( 22 ) connected between in the intake air flow direction (S) downstream of a throttle cap ( 24 ) and an internal combustion engine ( 1 ) in the intake tract ( 2 ) opens. Internal combustion engine ( 1 ) according to claim 1, wherein the first connection section ( 21 ) downstream of an air mass meter ( 19 ) in the intake tract ( 2 ) opens. Internal combustion engine ( 1 ) according to claim 1, wherein the nozzle ( 11 . 12 ) as a jet pump ( 31 . 32 ) is configured. Internal combustion engine ( 1 ) according to claim 1, comprising a parallel to the first nozzle ( 11 ) arranged second nozzle ( 12 ). Internal combustion engine ( 1 ) according to claim 4, comprising check valves ( 13 ), which are arranged so that only the first nozzle ( 11 ) or only the second nozzle ( 12 ) is flowed through. Internal combustion engine ( 1 ) according to one of the preceding claims, comprising a switching valve ( 33 ) to shut off the nozzle ( 11 . 12 ). Internal combustion engine ( 1 ) according to one of the preceding claims, which in a molding ( 34 ), which has a first connection ( 35 ) for connection to the first connection section ( 21 ), a second port ( 36 ) for connection to the second connection section ( 22 ) as well as a third connection ( 37 ) for connecting a brake booster ( 8th ) having. Use of an internal combustion engine ( 1 ) according to one of claims 1 to 7 arranged Venturi () for generating a vacuum in a brake booster ( 8th ).

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