DE202011050611U1 - Arrangement for providing a fuel-air mixture for an internal combustion engine - Google Patents

Abstract

Arrangement (100) comprising an air filter (10) and a membrane carburetor (20) for providing a fuel-air mixture for an internal combustion engine, wherein the membrane carburetor (20) via an intake passage (30) to the clean air side (14) of the air filter (10) and is provided with a control chamber (40) with a with the intake passage (30) connected to the fuel chamber (42), wherein the fuel chamber (42) is subjected to negative pressure from the intake passage (30) and by a for controlling the fuel supply to the fuel chamber ( 42) is separated from a compensation chamber (46), and wherein the compensation chamber (46) is connected via at least one compensation line (50) preferably to the clean air side (14) of the air filter (10), characterized in that the compensation line (50) is arranged at least one means (60) for throttling the prevailing in the compensation line (50) fluid flow.

Description

The present invention relates to an arrangement of an air filter and a diaphragm carburetor for providing a fuel-air mixture for an internal combustion engine, wherein the membrane carburetor is connected via an intake passage to the clean air side of the air filter and is designed with a control chamber with a suction chamber connected to the fuel chamber, wherein the fuel chamber is subjected to negative pressure from the intake passage and is separated from a compensation space by a control diaphragm designed to control the fuel supply to the fuel chamber, and wherein the compensation space is preferably connected to the clean air side of the air filter via at least one compensation line.

STATE OF THE ART

From the DE 10 2008 029 381 A1 is a generic arrangement of an air filter and a membrane carburetor for providing a fuel-air mixture for an internal combustion engine known. In order to achieve a position-independent operation of the membrane carburetor, the metered amount of fuel is not allowed, as with other carburetors by a float in a float chamber, but by a controller with a flexible membrane, which is referred to as a control membrane or control membrane. The control diaphragm is connected on a first side to the negative pressure in the intake passage, and on the other side is the control diaphragm with a compensation pressure, for example with ambient air pressure and / or the pressure of the clean air side of the air filter and / or the pressure of the intake duct and / or the pressure the crankcase of the internal combustion engine connected.

With this arrangement, both a fuel pump for allocating the fuel from a fuel tank to a fuel space and, on the other hand, a controller for metering the amount of fuel are integrated in the diaphragm carburetor. This controlling area is sealed by the control membrane against the environment, the control diaphragm forms an intermediate wall between the fuel-filled fuel chamber and a compensation space. The fuel chamber facing side of the control diaphragm is thus subjected to the negative pressure of the intake and the compensation space facing side of the control diaphragm is subjected to the pressure of the compensation chamber. When changing the pressure acting on the control membrane pressure ratio, the position of the control membrane is also changed. This changes the metering of the fuel in the gasifier and thus leads to a changed composition of the fuel-air mixture.

Depending on the design and the design of the equipped with a carburetor, especially with a diaphragm carburetor, internal combustion engine, it is possible that it emaciated under full load and falling speed, as disproportionately much air is supplied. In order to avoid this, it is known to connect the compensation chamber via a compensation path with a pressure source that depends on the engine speed. Such a pulsating pressure source, for example, the intake passage and thus also the air filter.

Depending on the speed of the internal combustion engine, pressure peaks may arise in the compensation chamber, in particular when the pressure oscillation in the intake duct and / or in the air filter causes resonance effects. The pressure peaks in the compensation chamber can lead to an allocation of a wrong amount of fuel, which causes disadvantages in the operation of the internal combustion engine, in particular with regard to the fuel consumption of the internal combustion engine.

It is therefore the object of the present invention to provide an arrangement of an air filter and a membrane carburetor for providing a fuel-air mixture for an internal combustion engine, with which the disadvantages of the above-described prior art are overcome and with the particular pressure peaks in the compensation chamber of the control chamber be avoided.

This object is achieved on the basis of an arrangement of an air filter and a membrane carburetor for providing a fuel-air mixture for an internal combustion engine according to the preamble of claim 1 in conjunction with the characterizing features. Advantageous developments of the invention are specified in the dependent claims.

DISCLOSURE OF THE INVENTION

The invention includes the technical teaching that at least one means for throttling the prevailing in the compensation line fluid flow is arranged in the compensation line.

The invention advantageously makes use of the possibility of arranging a means for throttling the fluid flow in the compensation line, which may be formed by a hose, a pipe or a duct. At pressure peaks in the clean air side of the air filter, these can not pass through the means for throttling in the compensation line or are at least throttled so much that the pressure peaks can not continue into the compensation chamber of the control chamber. The throttling means can be particularly progressive Have throttle behavior over a pressure difference before and after the means for throttling, so that a pressure compensation of the compensation chamber on the clean air side of the air filter remains possible, and only when the pressure difference above a threshold value, the throttle effect increases sharply.

The means may be formed as a throttle element with a throttle cross section, which is smaller than the flow cross section of the compensation line. The throttle cross-sectional area can be 20% to 80% and preferably 40% to 60% of the flow cross-sectional area of the compensation line, and it has been shown that the throttle element can advantageously be designed in the manner of a diaphragm, wherein the throttle element with the reduced throttle cross-section can have a flow length which can at least correspond to the throttle diameter.

According to a further advantageous embodiment of the arrangement according to the invention, the means may be designed as a foam element, preferably as an open-cell foam element. The foam element can be inserted, pressed in and / or glued into the hose line or into the pipeline which forms the compensation line. For example, the foam element may have a cylindrical shape or a rod shape, so that the foam element can be inserted into the compensation line. As a further alternative, the means for throttling may be formed by a metal foam body. This can be dimensionally stable and comprise, for example, a metal hydride. In particular, the metal foam may consist of an aluminum material.

The foam element may have a specific gravity of 10 kg / m ³ to 65 kg / m ³ and in particular have a porosity of 10 PPI (pores per inch) to 60 PPI (pores per inch). Both a throttle element in the manner of a diaphragm and a foam element can be used equally in the compensation line. Consequently, a combination of both means for throttling the flow of fluid in the compensation line is possible.

According to a further advantageous embodiment, the compensation line may have a bypass via which the compensation space can be optionally ventilated. The bypass forms a parallel compensation line at least on a portion of the compensation line, and means may be provided for guiding the flow of fluid through the compensation line and / or through the bypass.

The means for throttling can be arranged with particular advantage in the bypass. Furthermore, at least one switching element can be provided by means of which the optional connection of the bypass is made possible. If the means for throttling the fluid flow is in the bypass, then with the switching element, the fluid flow can be guided via the means for throttling, or the fluid flow is passed through the compensation line, without flowing through the means for throttling the fluid flow in the bypass.

For example, at low speeds of the internal combustion engine up to a limit speed, the fluid flow through the compensation line run without the bypass is flowed through. If the speed of the engine further increases, and the speed exceeds the limit speed, the switching element can pass the fluid flow through the bypass, so that the means for throttling the fluid flow is flowed through, and to achieve the effect of reducing the pressure peaks, so that in general a speed-dependent switching of the valve results, which takes place, for example, with a control device as a function of operating parameters of the internal combustion engine.

The switching element may for example be designed as a 2/2-way valve, which is preferably arranged in the compensation line and can be looped around by the bypass. Thus, the 2/2-way valve can block the fluid flow through the compensation line, so that the fluid flow is passed through the bypass and consequently via the means for throttling. Opens the 2/2-way valve, the main part of the fluid flow can be passed through the compensation line, and the bypass with the means for throttling is only slightly flowed through, without achieving a throttle effect.

According to another possible embodiment, the switching element may be formed as a 4/3-way valve, which can be brought into three mutually different switching positions. In a first switching position, a connection between the compensation chamber and the clean air side can be created free from the means for throttling. In a second switching position, a connection between the compensation chamber and the clean air side can be provided, in which the means for throttling is arranged, and in a third switching position, a connection between the compensation space and a surrounding atmosphere can be created. The 2/2-way valve and / or the 4/3-way valve can be controlled with a solenoid actuator, and the magnetic actuator can be brought via a control device of the internal combustion engine in particular depending on the speed in the corresponding switching position.

With even further advantage, the throttle element may be formed as a controllable throttle element, wherein a control device may be provided and connected to the controllable throttle element, such that the control device changes the throttle cross-section of the throttle element in dependence on operating parameters of the internal combustion engine. The control device can also be connected to the at least one switching element, so that the switching element can be controlled by means of the control device.

PREFERRED EMBODIMENTS OF THE INVENTION

Further measures improving the invention will be described in more detail below together with the description of preferred embodiments of the invention with reference to FIGS. It shows:

1 1 is a cross-sectional view of an arrangement for providing a fuel-air mixture for an internal combustion engine having an arrangement according to the invention of a means for throttling the fluid flow in a compensation line;

2 a possible embodiment of a means for throttling in a compensation line,

3 a further embodiment of a means for throttling a fluid flow in a compensation line,

4a an embodiment of a switchable means for throttling in a first switching position,

4b the embodiment of the switchable means for throttling in a second switching position and

5 a further embodiment of the arrangement of a switching element in the compensation line.

1 shows an arrangement 100 from an air filter 10 and a diaphragm carburetor 20 for providing a fuel-air mixture. In the housing of the diaphragm carburetor 20 is a suction channel 30 formed by an air filter 10 filtered ambient air sucks, the air intake via a throttle 38 and a starter flap 36 is regulated. The suction direction of the air is indicated by an arrow.

Over the intake channel 30 is due to the negative pressure formed in this via inlet openings 32 . 34 and 35 from a fuel room 42 Fuel sucked. The fuel room 42 is a control chamber 40 of the membrane carburetor 20 assigned and is by means of a flexible membrane 44 , the so-called control membrane, from a compensation room 46 separated. The control membrane 44 Controls the fuel supply from a fuel tank into the fuel chamber via an inlet valve 42 ,

For a pressure compensation in the compensation room 46 to create, this is about a compensation line 50 with the clean air side 14 of the air filter 10 connected. Particularly advantageous proves the through the compensation line 50 Conditional pressure equalization in particular at the first inlet opening 32 , via which the intake duct 30 the main part of the fuel is supplied.

Due to the connection of the compensation space 46 with the clean air side 14 through the compensation line 50 there is no directed flow in this. The flow in the compensation line 50 is therefore marked by double-sided arrows. Alternatively, the compensation room 46 vented through an opening in its wall to the atmosphere, so that the ambient pressure on the control membrane 44 acts.

To prevent unwanted pressure peaks, especially with resonance vibrations in the compensation line 50 , in the compensation room 46 is in the compensation line 50 a means 60 arranged to throttle the fluid flow. The middle 60 is exemplary executed in the manner of a throttle, and is intended to indicate only a throttling effect, without the symbolically represented means 60 would be limited to the type of throttle or, for example, a diaphragm.

2 shows a first embodiment of the means 60 for throttling the fluid flow in the compensation line 50 , The middle 60 is as a throttle element 61 trained, and is in the compensation line 50 arranged. The throttle element 61 has a centrally arranged bore, which has a throttle cross-sectional area 62 forms. The throttle cross-sectional area 62 may have a value that is only 40% to 60% of the flow cross-sectional area of the compensation line 50 is. The throttle element 61 may consist of a plastic or of a metal, wherein the throttle element 61 preferably has a resistance to oil and gasoline. For example, the throttle element 61 be designed as a metal turned part or as a plastic injection-molded component, and the funnel-shaped bevels shown 68 have. This favors the flow through the throttle opening.

3 shows a further embodiment for the formation of the agent 60 for throttling the flow in the compensation line 50 , The embodiment shows the means 60 as a foam element 63 that in the compensation line 50 is used. The foam element 63 has an open-cell foam, and is approximately cylindrical in shape to the compensation line 50 to be used.

The example in the 4a and 4b shows the compensation line 50 with a bypass 64 , In the compensation line 50 is a switching element 65 used, the arrangement of the switching element 65 in a section of the compensation line 50 is provided by the by-pass 64 is looped around. In the bypass 64 is the throttle element 61 arranged, which is exemplified switchable and with a variable cross section the means 60 forms for throttling. This is the throttle element 61 adjustable, and the control of the throttle element 61 takes place via the control device 67 , The switching element 65 is designed as a 2/2-way valve, and thus can take two switching positions.

4a shows the switching element 65 in a first switching position, with the compensation line 50 can not be flowed through. Consequently, the bypass becomes 64 with the agent 60 flows through to restrict the flow, so that the means 60 can develop its throttling effect.

In 4b is the switching element 65 shown in a second switching position, and the flow can through the compensation line 50 done without interruption. Consequently, the bypass becomes 64 only slightly or, as shown by the course of the double arrows, does not flow through.

5 finally shows a further embodiment of a switching element 66 in the manner of a 4/3-way valve 66 , The 4/3-way valve 66 can in three switch positions I . II and III to be brought. In a first switching position I can connect the compensation space 46 and the clean air side 14 free of funds 60 be created for throttling. This switch position I For example, can be taken by the 4/3-way valve when the internal combustion engine is operated only at low speeds. Furthermore, the 4/3-way valve 66 in a second switching position II be brought, with the connection between the compensation space 46 and the clean air side 14 is created, in which the means 60 is arranged for throttling. This switching position shown in the view, for example, then through the 4/3-way valve 66 be taken when the internal combustion engine is operated at high speeds.

Furthermore, the 4/3-way valve 66 in a third switching position III be brought, with the connection between the compensation space 46 and a surrounding atmosphere 70 , For example, the environment is created. The 4/3-way valve shown 66 can also by a control device 67 be controlled.

The invention is not limited in its execution to the above-mentioned preferred embodiment. Rather, a number of variants is conceivable, which makes use of the illustrated solution even with fundamentally different types of use. All of the claims, the description or the drawings resulting features and / or advantages including constructive details and / or spatial arrangements may be essential to the invention both in itself and in various combinations.

LIST OF REFERENCE NUMBERS

100

arrangement

10

air filter

14

Clean air side

20

carburetor

30

intake port

32

inlet port

34

inlet port

35

inlet port

36

choke

38

throttle

40

control chamber

42

Fuel space

44

Controlled Disc

46

compensation chamber

50

compensation line

60

medium

61

throttle element

62

Throttle cross-sectional area

63

foam element

64

bypass

65

Switching element, 2/2-way valve

66

Switching element, 4/3-way valve

67

control device

68

funnel-shaped slope

70

the atmosphere

I

first switching position

II

second switch position

III

third shift position

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 102008029381 A1 [0002]

Claims (12)

Arrangement ( 100 ) from an air filter ( 10 ) and a membrane carburetor ( 20 ) for providing a fuel-air mixture for an internal combustion engine, wherein the membrane carburetor ( 20 ) via a suction channel ( 30 ) with the clean air side ( 14 ) of the air filter ( 10 ) and with a control chamber ( 40 ) with one with the intake duct ( 30 ) connected fuel space ( 42 ) is executed, wherein the fuel space ( 42 ) with negative pressure from the intake channel ( 30 ) and by a for controlling the fuel supply to the fuel chamber ( 42 ) formed control membrane ( 44 ) of a compensation space ( 46 ) and the compensation space ( 46 ) via at least one compensation line ( 50 ) preferably with the clean air side ( 14 ) of the air filter ( 10 ), characterized in that in the compensation line ( 50 ) at least one means ( 60 ) for throttling in the compensation line ( 50 ) prevailing fluid flow is arranged. Arrangement according to claim 1, characterized in that the means ( 60 ) as a throttle element ( 61 ) with a throttle cross-section ( 62 ), wherein the throttle cross-section ( 62 ) is smaller than the flow cross-section of the compensation line ( 50 ). Arrangement according to claim 1 or 2, characterized in that the throttle cross-sectional area ( 62 ) 20% to 80% and preferably 40% to 60% of the flow cross-sectional area of the compensation line ( 50 ) is. Arrangement according to one of claims 1 to 3, characterized in that the means ( 60 ) as preferably open-pored foam element ( 63 ) is executed. Arrangement according to claim 4, characterized in that the foam element ( 63 ) has a specific gravity of 10 kg / m ³ to 65 kg / m ³ , and in particular has a porosity of 10 PPI (pores per inch) to 60 PPI (pores per inch). Arrangement according to one of the preceding claims, characterized in that the compensation line ( 50 ) a bypass ( 64 ) over which the compensation space ( 46 ) is optionally ventilated. Arrangement according to one of the claims 6, characterized in that the means ( 60 ) for throttling in the bypass ( 64 ) is arranged. Arrangement according to claim 6 or 7, characterized in that at least one switching element ( 65 . 66 ) is provided, by means of the optional connection of the bypass ( 64 ) is possible. Arrangement according to claim 8, characterized in that the switching element ( 65 ) as a 2/2-way valve ( 65 ) is formed, which preferably in the compensation line ( 50 ) and in particular from the bypass ( 64 ) is looped around. Arrangement according to one of the preceding claims, characterized in that the switching element ( 66 ) as 4/3-way valve ( 66 ) is formed, which - in a first switching position ( I ) a connection between the compensation space ( 46 ) and the clean air side ( 14 ) free of funds ( 60 ) creates for throttling, and preferably - in a second switching position ( II ) a connection between the compensation space ( 46 ) and the clean air side ( 14 ), in which the means ( 60 ) is arranged for throttling and preferably - in a third switching position ( III ) a connection between the compensation space ( 46 ) and a surrounding atmosphere ( 70 ) creates. Arrangement according to one of the preceding claims, characterized in that the throttle element ( 61 ) as a controllable throttle element ( 61 ), and wherein a control device ( 67 ) and with the controllable throttle element ( 61 ), in particular such that the control device ( 67 ) in dependence on operating parameters of the internal combustion engine, the throttle cross section ( 62 ) of the throttle element ( 61 ) changed. Arrangement according to one of claims 8 to 11, characterized in that the control device ( 67 ) with the at least one switching element ( 65 . 66 ), so that the switching element ( 65 . 66 ) by means of the control device ( 67 ) is controllable.

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