EP1141541B1 - Carburetor for internal combustion engines - Google Patents

Abstract

The invention relates to a carburetor for internal combustion engines, comprising a throttle device (1) which is positioned in an intake port (3) of an internal combustion engine and can be pivoted about a pivot axis, as well as an output device (5, 6) for the fuel being supplied which in the direction of flow (8) of the intake air is positioned downstream of the throttle device (1) in the intake port (3). The output device (5, 6) discharges the fuel into the intake port (3) in such a direction (7) that especially during lower part-load operations of the internal combustion engine when the throttle device (1) is only slightly open the fuel substantially strikes at least sections of said throttle device. The throttle device then atomizes the fuel in the intake air in the opening (14) embodied between the throttle device (1) and the intake port (3) in the area of greatest intake air flow speed.

Description

The invention relates to device for mixture formation in internal combustion engines according to Preamble of claim 1.

As an essential performance-determining effect on the operation of internal combustion engines, For example, gasoline engines or the like, the mixture formation of an ignitable fuel-air mixture as well as the ignition itself. For this purpose, a large number of devices on internal combustion engines are in the prior art have been proposed, in particular to improve performance the internal combustion engine, and thus to improve the operating conditions of the Internal combustion engine must cooperate.

In the area of mixture formation or mixture preparation and supply of the processed Mixtures to the combustion chambers of an internal combustion engine are essentially two mixture formation systems in use. With one system is the mixture formation according to the so-called carburetor principle, at e.g. a naturally aspirated engine with an ignitable fuel-air mixture is supplied that the air drawn in from the Venturi nozzle principle Fuel reservoir automatically draws fuel and this drawn fuel in the area of an intake duct leading to the combustion chambers, atomized and thus produces a fuel-air mixture that is as homogeneous as possible. Such, only very much here Simplified mixture preparation systems based on the gasifier principle are known in a large number of variants. A particular disadvantage of such It is carburetor systems that the intake of the fuel according to the Venturi principle especially in the so-called partial load range of the internal combustion engine, e.g. e.g. at idle or at only a little above idle speed Engine speed does not work optimally, since the one prevailing through the intake air Negative pressure for a uniform swirling of the entering into the intake duct Fuel is not necessarily sufficient. Consequences of this are inadequate Mixing of fuel and air and the resulting operating conditions the internal combustion engine, which manifests itself in a restless run. Conventional Various auxiliary systems are used for this in order for the internal combustion engine to run as evenly as possible to ensure in these partial load ranges. Such additional devices are expensive and also prone to errors.

The other known ones work on the principle of so-called injection Mixture processing systems in which the fuel is supplied by a fuel pump and an injection nozzle either in the intake port of the internal combustion engine or also with the so-called direct injection directly into the combustion chamber of the Internal combustion engine is injected. Such injection systems have the advantage that by controlling the injection pressure and the injection times a good influence mixture formation is possible. The injection, however, has that Disadvantage that the swirling of e.g. fuel injected into the intake duct through an injector is extremely inadequate, especially if not to be worked with too high injection pressures. The pure injection process therefore does not allow sufficient atomization of the fuel and mixing the sucked in air. To avoid this disadvantage, it is known the injection this fuel at one point when injected into the intake port to make the intake duct as close as possible to the inlet valves in the Combustion chamber is arranged. With such an arrangement of the injection device, ideally if an injection direction of the fuel is provided directly into the opening area of the intake valve, the atomization of the fuel by the Swirl effect when the intake air flows through the inlet valve exploited to increase the degree of atomization of the injected fuel manufacture. However, this has the disadvantage that the injectors must be arranged as close as possible to the inlet valves, which results in especially in the case of very compact engine designs, such as these, for example exist in the area of two-wheel engines or the like, result in space problems. The location of the injection devices and their direction of delivery must also Fuel jet can be determined and adjusted very precisely to ensure optimal atomization to ensure the fuel directly in the inlet area of the inlet valves.

From JP 6-173830 A (abstract) is a nozzle arrangement in the intake duct Internal combustion engine known, which injects into the area behind the throttle valve, in order to realize an oil enrichment in push operation with the throttle valve closed, as is typically known as additional lubrication in 2-stroke machines is.

An injection system is known from JP 1-300059 A (abstract), in which an injection nozzle is arranged in front of a throttle valve in the intake duct and on a surface the throttle valve injects a fuel jet. The direction of injection runs here so that the beam onto the throttle valve substantially near the axis of rotation strikes and especially in full load positions of the internal combustion engine for bridging of bottlenecks in the mixture supply that serves, for example, at abrupt opening of the throttle valve when moving from the partial load range in the full load range occur. This is due to a pressure collapse in the intake duct the atomization of the fuel jet is insufficient, it can even condense the fuel in such a sudden Transition between part load and full load occur. Apart from that the injector Arranged upstream of the throttle valve is just in the partial load range the fuel jet from the throttle valve reflects so that it is more likely adversely affects.

It is also known from DE-OS 2057308, a partition so inside to arrange the intake duct that a from a downstream injector radiated fuel jet hits directly on the partition. The The partition wall forms an air duct in the area opposite the injection nozzle, by the almost at a relatively large swivel position of the throttle valve all of the air drawn in must pass through, making it particularly good Mixing of intake air and injected fuel should take place. The disadvantage of this arrangement is that there is an optimal operating point then results when the throttle valve just has such an open position, that it is exactly the clear width of the through partition and intake duct released air guiding area, but this operating point by the rigid arrangement of the partition is fixed and can not be changed. There A sufficient volume of air must pass through this air guiding area for the lower partial load range from the arrangement of DE-OS 2057308 not an optimal one Atomization of the fuel can be expected. Also, due to the Arrangement of the intermediate wall of the fuel jet predominantly film-forming on this Precipitate partition wall and almost completely through evaporation mix with the air.

DE 3028244 A1 describes a device for atomizing a fuel jet known on a throttle valve, the larger opening angles of the throttle valve is effective and improves atomization.

JP 06159201 and JP 60027737 also show atomization devices in the area of a throttle valve, although the atomization is independent is caused by the opening position of the throttle valve.

An object of the present invention is therefore a device for mixture formation to propose to internal combustion engines that have a particularly good atomization of a fuel when the fuel is injected into an intake duct an internal combustion engine in lower part-load operation and a design-independent Optimization of mixture preparation allowed.

The solution of the problem according to the invention relating to a device for mixture formation on internal combustion engines results from the characteristic features of claim 1 in cooperation with the features of the preamble. Further advantageous embodiments of the invention result from the subclaims.

The invention according to claim 1 is based on a device for mixture formation on internal combustion engines, comprising one in an intake duct of an internal combustion engine arranged throttle device pivotable about a pivot axis as well as one behind in the intake duct in the flow direction of the intake air the throttle device arranged injection device for a supplied fuel. Such a device for mixture formation is further developed that the injection device is directed towards the edge of the throttle device, that the fuel in the lower part-load operation of the internal combustion engine is already in the range under 10% opening of the throttle device mainly on the edge Portions of the throttle device strikes and the fuel from the throttle device into the opening formed between the throttle device and the intake duct in the area of the greatest flow velocity of the intake air into the aspirated air atomized. The device for mixture formation according to the invention starts from the fact that the mixture formation especially for the lower partial load range should be optimized, in which, according to experience, about 75 % of the driving operation of an average internal combustion engine at only a maximum approx. 10% opening of the throttle device takes place. Conventional mixture preparation devices, especially carburetors, but are in the essential to the best possible performance of the engine in Full load range designed, whereby the operating behavior of the internal combustion engine, especially the mixture preparation for the lower partial load range, only unsatisfactory is solved or a high cost of construction by appropriate additional devices requires. To achieve the best possible atomization in this lower part load range in the present invention is the delivery device for the fuel in the flow direction of the intake air so behind the throttle device arranged and aligned so that the fuel in one direction the intake duct emits that the fuel as far as possible in the lower partial load range opened section of the throttle device at least partially on the throttle device meets itself and in those passed through the throttle device Volume flow of the sucked air atomized and due to the prevailing there swirled at the greatest flow velocity of the intake air and is mixed with the intake air. This results, especially in this a particularly good and homogeneous mixture formation in the lower part-load range themselves in a particularly quiet running of the internal combustion engine in this lower one Expressed partial load range. As a result, the device according to the invention stands out known injection systems from in front of a throttle valve or the like inject the intake duct. By hitting the fuel jet, without that additional parts must be provided within the intake duct, the Throttle valve used as a baffle plate, so that the impinging fuel jet on the one hand bounces off the throttle valve immediately again under atomization, on the other hand parts of the fuel jet are on the surface of the throttle valve knock down and through the air flow to the edge of the throttle valve be pushed so that this edge of the throttle valve is used as a tear-off edge which has an additional atomizing effect.

In the case of such an injection, there are lower flow velocities which are customary there the atomizing air has poor atomization efficiency in front. It is also advantageous compared to the known systems Injection close to the valve in the intake duct that problems in terms of space in the intake area close to the valve, since the injection in the proximity of the throttle device is also far from the inlet valves structurally favorable place of the intake duct can be made without this Reduce atomization efficiency.

In a further embodiment of the device for mixture formation, the Ratios in the atomization of the fuel depending on the Present pivot position of the throttle device, whereby the proportion between direct atomization by rebounding the fuel jet from the throttle valve as well as the atomization on the edge of the throttle valve which acts as a tear-off edge is characteristic for each swivel position of the throttle valve. Thus with the various load ratios of the internal combustion engine, which are in the position reflect the throttle valve, a favorable for partial load but also for full load Allow injection behavior to be set, in particular also by appropriate Shaping the surface of the throttle valve or adjacent parts the throttle valve can cause additional atomizing effects.

In a particularly advantageous embodiment, the injection device delivers the fuel under pressure as an essentially conically widening Jet in the intake duct, which means that the injection device is also a Conveniently located distance from the section open in the partial load range can have the throttle device. Therefore, the fuel jet becomes more appropriate Choice of injection direction even with changing opening conditions the throttle device in the lower part-load range essentially always in the range the greatest flow velocity through the between intake duct and throttle device formed opening and thus optimal atomization conditions cause. The problems of conventional carburetor designs are also particularly noticeable avoided with a vacuum suction of the fuel, so that by the control of the injection pressure of the fuel in the intake duct in particular good degrees of filling of the combustion chambers of the internal combustion engine can be achieved. By controlling the overpressure used in each case, one is also special good adaptation to the respective operating conditions of the internal combustion engine possible.

In a particularly advantageous embodiment, the throttle device can be a throttle valve with, advantageously central, rotationally movable articulation of the throttle valve be in the intake duct. Such throttle valves are generally known and form an approximately sickle-shaped in the lower part-load range on both sides of their axis of rotation Passage area for the intake air. Exactly in this area the crescent Opening between throttle valve and intake duct is in the invention Way the fuel jet is injected.

In a further embodiment, at least one outlet opening can be used as the injection device having injector can be provided, which is known in principle Way can deliver a single fuel jet into the intake duct. Such injection nozzles are widely known. It goes without saying that too several such injectors or array-like arrangements of such injectors corresponding design in the device for mixture formation according to the invention can be provided.

The device for mixture formation according to the invention can be designed in a further embodiment be designed such that the inlet opening of the Fuel is designed such that fuel is at least partially on the throttle device hits and the throttle device the delivered fuel in the flow direction deflects. For example, when designing the throttle device as a throttle valve, the opening angle of the throttle valve is approximately in the full-load range Be 90 °, so that the throttle valve extends approximately parallel to the direction of flow the sucked air comes to rest. With such training hits the emitted fuel jet from a size-dependent opening angle the throttle is no longer directly in the area of the largest Flow rate, but at least partially on the throttle valve. Since at full load the flow rate in the delivery area of the fuel is significantly lower than in part-load operation, the delivery of the fuel jet has an effect on the throttle device also positive in full load operation, since the on Throttle device impinging fuel jet on the one hand from the throttle device is deflected in the direction of flow of the intake air and at the same time when hitting the throttle device and when draining via the Edges of the throttle device is atomized.

Of particular advantage in the device for mixture formation according to the invention is that the mixture formation facility for retrofitting to existing ones Internal combustion engines can be provided. For example, it follows from the legal requirements for reducing the exhaust gas pollution of older internal combustion engines the requirement that older internal combustion engines e.g. on motorcycles or vehicles of older construction can be retrofitted with new technology in this way must meet the applicable legal requirements for exhaust gas behavior comply. The retrofitting of such existing internal combustion engines can only be carried out economically if in one embodiment of the invention Device for mixture formation this device is connection compatible to carburettors and injection systems provided on existing internal combustion engines or the like is formed. This can be done without extensive Reworking on the existing internal combustion engines will be necessary by simply replacing the built-in carburetor with the Device for mixture formation according to the invention the conversion of the internal combustion engine be made. It is a further advantage that in a further embodiment the device for mixture formation regardless of the type of existing Internal combustion engine provided carburetor and without adjustment predetermined arrangements of the intake valves or the like of the internal combustion engines can be retrofitted. By dispensing the fuel in the area of the throttle device and thus e.g. structurally distant from the inlet valves one such standardized device according to the invention for mixture formation for a Large number of differently constructed internal combustion engines are used become. It is therefore only an insignificant adaptation of the invention Device for mixture formation on the respective existing construction of the engine as well as the position of intake valves, intake duct or the like. This can be achieved particularly advantageously in that only Flange devices of the device according to the present invention Dimensions of the carburetor are adjusted.

It when the device for mixture formation as a replacement for is particularly advantageous Flat current carburetor is used on internal combustion engines for two-wheelers, because straight Such flat-flow carburettors have extremely limited space, at retrofitting with injection systems working close to the valve is extremely problematic are.

It is also conceivable that a sensor for, preferably continuous detection of the opening position of the throttle device is provided. Such a sensor is used to transmit the information via the respective position of the throttle device e.g. to a digital engine control.

Due to the particularly favorable atomization of the fuel in the invention Device for mixture formation will continue to be the consumption of fuel, preferably in the lower part-load range of the internal combustion engine, compared to the use conventional carburetor reduced, thereby ensuring compliance with the law increasingly stringent exhaust gas regulations is also further improved.

The injection pressure can also be used in the device for mixture formation according to the invention of the fuel in the intake duct compared to conventional injection systems can be reduced with injection close to the valve because of the better atomization in the area of the greatest flow velocity of the intake air the otherwise high injection pressures are unnecessary. This can be for example, reduce the pump output of the injection pump, especially when retrofitting existing internal combustion engines in their available power due to the electrical power supply can be limited, for example.

It is also conceivable that in the device for mixture formation according to the invention the time of dispensing fuel and the quantity of fuel dispensed can be predefined in the intake duct by sensors arranged on the internal combustion engine with which the operating state of the internal combustion engine, in particular the Angular position of the crankshaft and its speed can be detected. As a result, a further adjustment of the fuel injection and in particular the Atomization conditions in the lower part-load range can be brought about, resulting in a further improvement of the smooth running of the internal combustion engine can be achieved can.

Particularly preferred embodiments of the device according to the invention for The drawing shows mixture formation.

Figur 1 -

eine Einrichtung zur Gemischbildung an Brennkraftmaschinen aus dem Stand der Technik mit Einspritzung des Kraftstoffes nahe des Einlaßventiles,

Figur 2 -

eine Ausführungsform der erfindungsgemäßen Einrichtung zur Gemischbildung mit nahe der Drosseleinrichtung angeordneter Einspritzung des Kraftstoffes, dargestellt im Teillastbereich,

Figur 3 -

eine Einrichtung gemäß Figur 2, dargestellt im Vollastbereich der Brennkraftmaschine.

Show it:

Figure 1 -

a device for mixture formation on internal combustion engines from the prior art with fuel injection near the inlet valve,

Figure 2 -

1 shows an embodiment of the device for mixture formation according to the invention with fuel injection arranged near the throttle device, shown in the partial load range,

Figure 3 -

a device according to Figure 2, shown in the full load range of the internal combustion engine.

FIG. 1 shows a device for mixture formation known in the prior art shown, in which the injection of the fuel by means of an injection device 6 with an injection nozzle 5 in an intake duct 3 in such a way that the fuel jet 9 substantially in the inlet area of the inlet valve 10 in the Combustion chamber 11 of the internal combustion engine on the volume flow of the intake air hits and is atomized there. The sucked-in air occurs in the flow direction 8 through the suction side flange 4 of the device and is in its quantity changed by a throttle valve 1 on both sides around a throttle valve shaft 2 is adjustable in the pivoting direction 15. Depending on the desired operating status the internal combustion engine, the throttle valve 1 is either in the pivoting direction 15 opened or closed, with only small opening areas, especially in the partial load range are present in the form of gap regions 14 arranged at the top and bottom. The sucked-in air with the highest flow velocity passes through these gap regions 14 through, after the passage of the gap areas 14 the The flow rate of the intake air decreases again significantly. Here is in the prior art, the injection device 6 between the throttle valve 1 and the inlet valve 10 arranged that the delivery of the fuel jet 9 from the injection nozzle 5, especially in this area of relatively low flow velocities takes place. Therefore, the fuel jet 9 must run along the injection direction 7 be directed precisely into the area that ultimately near the intake valve 10 one Swirling of the fuel jet 9 with the sucked-in air brings about that intake air in the area of the inlet valve 10 is in turn greatly accelerated. Since the storage and control of the intake valve 10 is complicated and relative requires high volume, the injector 6 is relatively far from the inlet valve 10 come to lie away. As a result, the injected fuel jet reaches 9 but not necessarily the area of greatest flow velocity of the intake air in the area of the inlet valve 10, thereby causing the atomization of the fuel jet 9 is insufficient.

In the proposed configuration of the device according to the invention for In contrast, the mixture formation according to FIG. 2 is the atomization of the fuel jet 9 regardless of the arrangement of a combustion chamber 11 or an intake valve 10 arranged in the area of a throttle device, here a throttle valve 1 can be located at a convenient location within the intake duct 3. The Intake duct 3 is in an example of a tubular intake manifold 16 provided, in which, for example, a throttle valve 1 in principle known manner around a throttle valve shaft 2 in the pivoting direction 15 on both sides can be pivoted. Approximately perpendicular to the direction of flow 8 of the suctioned In an embodiment according to the invention, air becomes an injection device 6, for example arranged with an injection nozzle 5 such that the fuel jet 9 in Injection direction 7, here approximately perpendicular to the flow direction 8 of the drawn Air takes place. However, this is not the vertical arrangement of the flow direction 8 and injection direction 7 of importance, but it comes first insists that the location of the. Injection device 6 and the injection device 7 so be chosen that the fuel jet 9 particularly in the lower part-load range thus between the gap region 14 which forms when the throttle valve 1 is opened Throttle valve 1 and intake duct 3 is directed that the fuel jet 9 in Area of greatest flow velocity of the intake air through the Gap area 14 mixed with the sucked air and atomized. This is from Another advantage is that the injection device 6 is sucked in the flow direction 8 Air is arranged behind the throttle valve 1, particularly in the lower Partial load range of the fuel jet 9 runs virtually in the slipstream of the throttle valve 1 and essentially only interact with the sucked-in air in the gap region 14 and can be atomized. One detrimental to fine atomization Deflection of the fuel jet 9 in the area of not so high flow velocities the sucked in air does not take place or only insignificantly.

This assignment of the injection direction 7 of the fuel jet 9 and the flow direction 8 of the air sucked in through the gap area 14 becomes special good atomization of the fuel achieved, for example, even at relative low injection pressures with which the injection device 6 can work is present. The particularly good atomization also makes it particularly homogeneous Combustion of the mixture formed is possible, resulting in an overall reduction fuel consumption while reducing harmful emissions is possible.

In particular for retrofitting existing internal combustion engines, for example due to increased demands on the amount of dispensed Exhaust gases, it is favorable that the device for mixture formation according to the invention largely independent of the structural position of the mixture feed in is the combustion chamber 11 of an internal combustion engine because of the high flow velocities in the area of the inlet valves 10 of an internal combustion engine for atomization and mixture formation are not required at all. This can easily an exchange of a conventional carburetor system, for example old internal combustion engine only by removing the carburetor and by one in the area of the suction-side flange 4 and the valve-side Flange 13 connection-compatible design of the intake 16 are replaced can. For example, a possibly provided one can not go further Shown sensor for detecting the position of the throttle valve 1 connection compatible be designed.

3 shows the device according to the invention for mixture formation in the full-load range shown, with the description of the basic structure of device for mixture formation according to the invention is referred to FIG. 1. The Throttle valve 1 is essentially parallel to the flow direction in the full-load range 8 of the intake air aligned, which means there are no explicit gap areas 14 for the passage of the intake air through between the throttle valve 1 and intake duct 3 results in more opening. In this full load range the Internal combustion engine comes rather subordinate to the atomization of the fuel Significance to, it is particularly important that a corresponding Amount of fuel is introduced into the combustion chamber 11 of the internal combustion engine. This can be further in the mixture formation device according to the invention thereby improve that the fuel jet 9 on the perpendicular to the injection direction 7 arranged throttle valve 1 hits and atomized there like a baffle plate becomes. For example, the fuel jet 9 striking the throttle valve 1 accelerated towards the edges of the throttle valve 1 and can be finer there Droplets entrained by the intake air flowing around the throttle valve 1 become. Furthermore, the throttle shaft 2 can be provided with a bevel 17 are in the form of a surface section reflecting the fuel jet 9 the deflection of the fuel jet 9 in the flow direction 8 causes and thus also to good atomization of the fuel jet 9 also in the Full load operation contributes.

Part number list

1 -

throttle

2 -

throttle shaft

3 -

intake port

4 -

Inlet flange

5 -

injection

6 -

Injector

7 -

Injection direction

8th -

Air flow direction

9 -

Fuel jet

10 -

intake valve

11 -

combustion chamber

12 -

block

13 -

Valve side flange

14 -

gap region

15 -

pan direction

16 -

intake

17 -

bevel

Claims (10)

1. Device for the carburation in combustion engines, showing a throttling unit (1) placed in an inlet channel (3) of a combustion engine, which is turnable around a swivel pin, as well as an injection unit (5, 6) for a supplied fuel which is placed in the inlet channel (3) behind the throttling unit (1) respective to the direction of flow (8) of the taken in air,
   characterized in that
   the injection unit (5, 6) is directed in such a manner to the edge of the throttling unit (1), that in the state of lower underload operation mode of the combustion engine even in the range of less than 10 % of the opening of the throttling unit (1) the fuel impacts predominantly onto sections at the edges of the throttling unit (1) and the fuel is sprayed from the throttling unit (1) into the opening (14) which is formed between the throttling unit (1) and the inlet channel (3) in the area of the highest velocity of flow of the taken in air.
2. Device for the carburation in accordance with claim 1, characterized in that the conditions of the spraying of the fuel change according to the respectively present swivel position of the throttling unit (1).
3. Device for the carburation in accordance to one of the claims 1 or 2, characterized in that the injection unit (5, 6) delivers the fuel under excess pressure into the inlet channel (3) as a beam (9) which is essentially formed conically enlarging.
4. Device for the carburation in accordance to one of the preceding claims, characterized in that that a throttle valve is provided as a throttling unit (1) with an advantageously centrally fixed, rotationally movable coupling (2) of the throttle valve (1) inside of the inlet channel (3).
5. Device for the carburation in accordance to one of the preceeding claims, characterized in that as injection unit (6) an injection nozzle (5) is provided showing at least one outlet.
6. Device for the carburation in accordance to one of the preceding claims, characterized in that also in the full load operation mode the inlet direction (7) of the fuel is formed in such a way, that fuel impacts at least partly onto the throttling unit (1) and the throttling unit (1) deviates the delivered fuel into the flow direction (8).
7. Device for the carburation in accordance to one of the preceding claims, characterized in that the device for the carburation is provided for retrofitting of existing combustion engines.
8. Device for the carburation in accordance with claim 7, characterized in that the device for the carburation is provided connection-compatible to carburettors, injection arrangements or the like scheduled at existing combustion engines.
9. Device for the carburation in accordance to one of the claims 7 to 8, characterized in that the device for the carburation is usable for combustion engines at two-wheeled vehicles.
10. Device for the carburation in accordance to one of the preceeding claims, characterized in that the time for delivering of fuel and the amount of fuel delivered into the inlet channel (3) is providable by sensors arranged at the combustion engine, with which the operating state of the combustion engine, respectively the rotational position of the crankshaft (27) and/or their rotational speed can be taken.

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