EP1621776B1 - Internal combustion engine with a device for vacuum generation - Google Patents

Description

The invention relates to an internal combustion engine with an air supply channel and arranged in this air supply duct first means for generating a negative pressure, which generates a negative pressure by utilizing energy components of the air supply channel flowing through the air flow, wherein the internal combustion engine is equipped with at least one main vacuum line, which in the air supply duct opens and with a negative pressure in this air supply channel can be tapped.

Furthermore, the invention relates to the use of such an internal combustion engine.

According to the prior art, internal combustion engines, such as the generic engine mentioned above, are equipped, in particular, with a device for generating a negative pressure when operated with a throttle-free load control. For this reason, short position for throttle-free load control in general is taken in the following. In particular, it will be explained why an increasing development towards throttle-free operated internal combustion engines is to be observed and what consequences this entails for the conceptual design of an internal combustion engine.

Due to the limited resources of fossil fuels, especially due to the limited presence of mineral oil as a raw material for the production of fuels for the operation of internal combustion engines, the development of internal combustion engines is constantly striving to minimize fuel consumption, with an improved d. H. more effective combustion is at the forefront of the effort.

The problem is the fuel consumption and thus the efficiency, especially in gasoline engines. The reason for this lies in the basic working method of the gasoline engine. The Otto engine works with a homogeneous fuel-air mixture, that - if there is no direct injection - is prepared by external mixture formation by fuel is introduced into the intake air in the air supply channel. The desired power is adjusted by changing the filling of the combustion chamber, so that the operating method of the gasoline engine - unlike the diesel engine - is based on a quantity control.

This load control is usually carried out by means provided in the air supply passage throttle. By adjusting the throttle, the pressure of the intake air behind the throttle valve can be reduced more or less. The further the throttle is closed d. H. the more it obstructs the air intake passage, the higher the pressure loss of the intake air across the throttle and the lower the pressure of the intake air behind the throttle and before the intake into the combustion chamber. With a constant combustion chamber volume, the air mass, i. E. the quantity will be set.

The quantity regulation by means of throttle valve has thermodynamic disadvantages. In particular, due to the pressure reduction of the intake air, it leads to larger charge exchange losses. This also explains why this type of load control proves disadvantageous especially in the partial load range, because low loads require high throttling and pressure reduction in the air supply duct.

In order to reduce the throttle losses described and thus to reduce fuel consumption, various load control strategies have been developed which seek to dethrottle the engine, preferably by completely eliminating the throttle.

One approach to de-throttling the Otto engine method is to use a variable valve train. In contrast to conventional valve trains, in which both the stroke of the valves and the timing, ie the opening and closing times of the intake and exhaust valves, due to the non-flexible, as non-adjustable mechanism of the valve train are given as immutable sizes, they can the combustion process and thus the Fuel consumption influencing parameters are varied by variable valve trains more or less. The quantity control of the gasoline engine, ie the air or fresh mixture mass supplied to the combustion chamber, is not realized or regulated by means of a throttle valve, but via the variation of the timing and the stroke. With the throttle also eliminates the disadvantages associated with the throttle, in particular the throttle losses.
Due to the fact that in the gasoline engine due to the principle throttling in the partial load high charge exchange losses occur with the resulting relatively poor partial load efficiencies and on the other hand the diesel engine quality control leads to a relatively good efficiency in the partial load range and thus to a favorable fuel consumption, attempts were made early on, to combine both working methods.

Another approach to Entdrosselung according to the prior art therefore consists in a ottomotorischen working method with stratified combustion chamber charge. The stratified charge is in contrast to the otherwise homogeneous mixture, which sucks the gasoline engine, a way to operate a gasoline engine within narrow limits by means of a quality control. In this case, the direct injection of the fuel is a suitable means for realizing the stratified combustion chamber charge. The direct injection of the fuel into the combustion chamber leads in this way also, although not always to the complete omission of the throttle, so at least to reduce the throttle losses due to a smaller and less frequently required throttling.

The market share of gasoline engines, which have a direct injection and / or a variable valve train, is constantly increasing, which is why these engines are becoming increasingly important for car manufacturers.

A disadvantage of this development or of these motors is that the supply of so-called vacuum consumers made more difficult. Namely, according to the state of the art, the negative pressure arising behind the throttle valve in the air supply duct, which is due to the throttling of the sucked air flow inevitably builds up, used to certain devices - so-called vacuum consumers - to pressurize the engine with negative pressure. The area behind the throttle is used as a vacuum source.

For example, a brake booster for proper operation via a vacuum line must be supplied with negative pressure, which is why this brake booster in conventional internal combustion engines preferably by means of a vacuum line, which opens behind the throttle in the air supply duct, with negative pressure. An exhaust gas recirculation system, a tank ventilation, an air conditioning system or an automatic transmission are further examples of such vacuum consumers.

However, this results for Entschrosselte internal combustion engines, for example, for internal combustion engines, which are equipped with a variable valve timing and / or direct injection, especially for internal combustion engines, in which the throttle is completely eliminated, the need or the need to provide an alternative vacuum source available to continue to supply the vacuum consumers.

The problem described a missing or insufficient vacuum source occurs, moreover, even in conventional equipped with a throttle engine, when these engines in full load d. H. work with the throttle fully open unthrottled.

According to the prior art, Venturi nozzles or a Venturi nozzle-like channel elements are provided in the air supply channel to ensure the supply of vacuum consumers

DE 198 21 686 A1 describes a check valve unit, which serves a vacuum requiring working system of a vehicle, for example, the servo motor of a power steering or the brake booster one Vehicle brake system to connect with a negative pressure generating suction system, for example, the intake manifold or the intake port of an internal combustion engine. The check valve unit is intended to ensure that a negative pressure generated and required in the work system is maintained, even if the negative pressure rises or the vacuum generation in the suction system is completely interrupted. Therefore, even if the internal combustion engine described in DE 198 21 686 A1 is equipped with a throttle valve, the disclosed check valve unit can in principle also be used in internal combustion engines which have no throttle valve.

To ensure the supply of the work systems with a sufficiently high negative pressure and maintain this negative pressure, the check valve unit has a main channel, which is connected via its inlet to the working system, which is to be subjected to negative pressure, and with the interposition of two check valves in two places opens into an outside air channel. This outside air duct, which can also be referred to as an air supply duct with regard to the generic type internal combustion engine, is connected via its inlet to the air intake system of the internal combustion engine and leads via an intake duct to the combustion chamber or the combustion chambers of the internal combustion engine. In the outside air duct, a Venturi tube is arranged with a conventional cross-sectional constriction in a Venturi tube, wherein a connecting line between the main channel and outer air channel, which is referred to as Venturi channel, opens in the region of the cross-sectional constriction in the outer air channel. The second connection line opens downstream into the outside air channel.

Starting from a pressure-balanced situation, when the engine is started, air is extracted from the connected working system, predominantly via the second connecting line. When a certain vacuum level is reached, the non-return valve arranged in the second connecting line is closed and only air is sucked out via the Venturi channel. The outside air is sucked in through the Venturi tube, whereby the air flow is accelerated with increasing cross-sectional constriction, resulting in a lowering the static pressure that leads to the formation of a negative pressure in the Venturi tube. In the region of the narrowest cross section of the Venturi tube, this negative pressure is tapped by means of the first connecting line. The working system requiring this negative pressure is supplied with this negative pressure via the first connecting line and the main channel.

Thus, DE 198 21 686 A1 discloses an internal combustion engine of the generic type, namely an internal combustion engine, with an air supply channel and arranged in this air supply duct first means for generating a negative pressure, wherein the negative pressure can be tapped by means of a vacuum line.

The device for generating the negative pressure, which in the present case is designed as a Venturi nozzle or as Venturi tube, uses energy components of the air flow flowing through the air supply channel in the sense of the present invention. As an energy component, the kinetic energy of the vent flow is utilized by lowering the static pressure by increasing the flow velocity in order to generate a negative pressure in this way. Other forms of energy portions of the airflow within the meaning of the present invention are discussed below in connection with International Patent Application WO 00/29734.

DE 43 44 624 A1 describes a check valve, which is arranged in the vacuum line of an internal combustion engine. The check valve comprises a one-piece valve body having an inlet and an outlet, the inlet communicating with the outlet via a passage in which a Venturi tube is arranged. This passage can again be regarded as an air supply channel in the sense of the present invention.

As in the previously described check valve unit according to DE 198 21 686 A1, the air supply channel is connected with the interposition of a check valve by means of two connecting lines with another channel having at least two outlets, connected to the vacuum consumers can be. The first connecting line opens in the region of the cross-sectional constriction of the Venturi tube in the air supply channel. The other, second connecting line leads downstream in the air supply channel.

In this way, the vacuum consumers can be acted upon with the negative pressure generated in the air supply channel, in particular with the negative pressure generated in the Venturi tube as a result of the acceleration of the air flow. If the pressure in the air supply duct is higher than the pressure on the side of the vacuum consumers close the check valves.

By means of the non-return valve described in DE 43 44 624 A1 thus means for generating a negative pressure can be formed to provide, for example, brake booster, automatic transmission and the like safe and sufficient with a sufficiently large negative pressure and maintain it.

The international patent application WO 00/29734 describes an internal combustion engine which is equipped for the realization of a throttle-free load control with gas exchange valves, which are fully variable controllable via a motor control. Due to the lack of throttle and the resulting negative pressure behind the throttle valve means for generating a negative pressure must be provided.

For this purpose, WO 00/29734 proposes a device which uses the energy components of the air flow flowing through the air supply channel to generate a negative pressure. The energy components used in the device on the one hand, the flow velocity of the air flowing through the air supply channel, whereby a corresponding reduction of the static pressure is brought about by increasing the flow velocity, and / or the resulting pulse-like pressure fluctuations due to a periodic opening of the gas inlet valves in the air flow in the air supply channel exploited, which can fall below the ambient pressure and generate in this way a negative pressure.

A proposed embodiment of the device provides for the arrangement of a Venturi tube in the air supply channel, wherein the negative pressure generated in the Venturi tube can be tapped via a vacuum line. A negative pressure consumer is connected by means of this vacuum line with the means for generating the negative pressure or with the air supply channel and supplied with negative pressure.

WO 00/29734 therefore also describes an internal combustion engine of the generic type.

In addition, reference is made to DE 692 17 182 T2, which relates to a vacuum booster valve. This vacuum boost valve also has a venturi d. H. a device for generating a negative pressure and serves to supply the vacuum consumers of an internal combustion engine with a sufficiently large negative pressure and thus to ensure the function of the partially indispensable auxiliary systems of an internal combustion engine, such as a brake booster.

Finally, it should be noted that diesel engines in principle, i. due to the load control by means of quality control have no throttle and must be equipped according to the prior art with a separate vacuum pump to generate a negative pressure, which is costly. These vacuum pumps also require a drive and additional drive energy, which must be provided by the internal combustion engine and reduces the output power.

The detailed description of the state of the art makes clear, on the one hand, that in principle there is an unavoidable need for devices which provide the negative pressure required for the safe operation of an internal combustion engine, in particular with regard to current engine concepts with a throttle-free load control, namely with a direct injection and / or or a variable valve timing.

On the other hand, however, it is also clear that the devices proposed according to the prior art have significant disadvantages. In particular, they are very complex and therefore very prone to failure and very expensive, with a separate vacuum pump - as it is currently used in diesel engines - not only very expensive, but also has a high additional space requirements. But this high space requirement is the goal of the designers, in the engine compartment of the motor vehicle as effective as possible d. H. To realize dense packaging of the entire drive unit, contrary.

Another significant disadvantage of conventional means for generating a negative pressure is also that these facilities can not provide a sufficiently high vacuum with the necessary security in all operating points. This is questionable especially with regard to auxiliary systems such as the brake booster but also with regard to a possibly existing servomotor power steering, since I am in these auxiliary systems to systems that have direct influence on driving safety, so that a sufficiently high negative pressure considered indispensable is.

Against this background, it is the object of the present invention to provide an internal combustion engine with an air supply channel and arranged in this air supply channel means for generating a negative pressure, with the vacuum consumers of the internal combustion engine, a sufficiently large negative pressure can be safely provided and with the According to the prior art known disadvantages are overcome, which thus in particular has a device for generating a negative pressure, which is less expensive than conventional devices.

A further sub-task of the present invention is to show uses of such an internal combustion engine.

The first sub-task is solved by an internal combustion engine with an air supply duct and with a first arranged in this air supply duct A device for generating a negative pressure which generates a negative pressure by utilizing energy components of the air flow flowing through the air supply duct, wherein the internal combustion engine is equipped with at least one main vacuum line, which opens into the air supply channel and with which a negative pressure in this air supply channel can be tapped, and characterized is that in the at least one main vacuum line, a second means for generating a negative pressure is arranged, which generates a negative pressure by utilization of energy components of the at least one main vacuum line flowing through the air flow.

According to the invention in the first device - which is arranged in a conventional manner in the air supply duct - created negative pressure by means of a main vacuum line and amplified by means of a further second device which is provided in the main vacuum line. The static pressure of the air flow is lowered in this way in a two-stage process to a level that can not be realized with conventional means for generating a negative pressure - as described in the introduction - or only at the expense of adjusting unacceptable disadvantages in terms of Operation of the internal combustion engine can be realized.

Although an arbitrarily low pressure level could be generated with conventional devices of the prior art, for example, if the cross-sectional constriction of the Venturi tube is chosen to be sufficiently small. With increasing cross-sectional constriction but also correspondingly large flow resistance in the air supply channel, which are associated with performance losses and efficiency losses.

Characterized in that in the internal combustion engine according to the invention, a second means for generating a negative pressure is provided away from the air supply channel, the generation of a sufficiently high negative pressure is possible without adversely affecting the flow in the air supply channel, the supply of the internal combustion engine with combustion air or Fresh mixture is used and therefore basically a low flow resistance should have. The generation of the negative pressure and the supply of the internal combustion engine with combustion air or fresh mixture is not completely decoupled in this way, but partially and to a considerable extent.

In addition, the proposed device for generating a negative pressure can be realized with a relatively low cost. In particular, because - as the introduction can be seen - already conventional internal combustion engines are often equipped with a first means for generating a negative pressure in the air supply duct and have a vacuum line for tapping this negative pressure, so that for the formation of an internal combustion engine according to the invention only a second device for generating a negative pressure in the already existing vacuum line, which is referred to as the main vacuum line according to the invention, must be arranged.

For this reason, the proposed solution according to the invention for generating a sufficiently high negative pressure is also suitable for retrofitting already on the market internal combustion engines, which is fundamentally advantageous in terms of the introduction of new concepts, if it is taken into account that the average life of an internal combustion engine is more than ten years , Thus, internal combustion engines located in traffic can be converted to the internal combustion engine according to the invention by inserting a second device for generating a negative pressure in the already existing main vacuum line.

An additional space requirement is also not given, but at least negligible, so that the internal combustion engine according to the invention does not preclude the most effective possible packaging of the entire drive unit. This is a significant advantage of the present invention, particularly as compared to the prior art diesel engine separate vacuum pump.

Thus, the first underlying object of the invention is achieved by the internal combustion engine according to the invention, namely to provide an internal combustion engine with which a sufficiently large negative pressure can be safely provided and which is in particular less expensive than conventional internal combustion engines.

Further advantageous embodiments of the internal combustion engine are explained in connection with the subclaims. It will also become apparent which possibilities the internal combustion engine according to the invention opens above the advantages already set out above.

Particularly advantageous embodiments of the internal combustion engine, in which the first means for generating a negative pressure is formed as a nozzle, which has a cross-sectional constriction. The air flow in the nozzle is accelerated due to the narrowing cross-section, whereby the static pressure is lowered. This embodiment uses as an energy component, the flow velocity of the air flowing through the air supply duct to generate the negative pressure, without additional measures are required, in particular no additional auxiliary power is needed.

Embodiments of the internal combustion engine in which the size of the cross section of the cross-sectional constriction is variable are advantageous. As a result, the cross-sectional constriction can be adapted to the respective operating state. At low speeds or low loads sufficiently large negative pressures can be generated in this way even with the then present small air mass flows with correspondingly narrow flow cross sections. These narrow flow cross sections, which represent an undesirable flow resistance with increasing speed or increasing load due to the increasing air mass flows, can then be adapted in a targeted manner. be enlarged.

Embodiments of the internal combustion engine in which this first device for generating a negative pressure is designed as a Venturi nozzle are advantageous. This offers advantages because a Venturi nozzle or a Venturi tube the Air flow with only slight flow losses in a certain section accelerated briefly. The flow is influenced and disturbed only insofar as it is necessary for the generation of a sufficiently high negative pressure, the venturi was designed just for this application. In addition, a Venturi tube is a known component, so that there is sufficient knowledge and experience with regard to the use of such a tube, which not only simplifies the design of the internal combustion engine according to the invention, but also makes it more cost-effective.

Embodiments of the internal combustion engine in which the first device designed as a nozzle for generating a negative pressure is formed as part of the air supply channel are advantageous, in that the outer walls of the nozzle form part of the outer walls of the air supply channel. In this case, the nozzle is preferably formed integrally with the air supply channel as a monolithic component. This is particularly appropriate in embodiments of the internal combustion engine, in which the air supply channel is designed as Ansaugsammelrohr. The intake manifold is usually a molded, often injection molded plastic part, so that the design of the nozzle already in the design and manufacture of the intake manifold can be considered. An assembly of the nozzle is omitted in this embodiment, which supports the solution of the invention underlying task to provide a cost-effective concept as possible.

However, embodiments of the internal combustion engine may also be advantageous in which the first device designed as a nozzle for generating a negative pressure in the air supply channel is arranged in such a way that the nozzle is surrounded by the air supply channel, so that the air flow can flow through the nozzle inside and outside , In this way, not all of the air flow passage through the air supply passage is passed through the nozzle and constricted, but only a more or less small partial flow. The remaining part of the air flow is passed outside the nozzle and remains almost unaffected.

It is considered that, especially at high speeds and the then present large air mass flows, the constriction of the flow cross-section - as stated above - also disadvantages, especially a power loss, can bring with it, it seems reasonable, the supply of the internal combustion engine via the air supply channel not too much to disturb or influence, which can be achieved by providing the air flow under all operating conditions, a sufficiently large flow area available. The present embodiment ensures this by offering the flow between the air supply duct and the nozzle an unchangeable cross-section available under all operating conditions

Also advantageous in this embodiment, embodiments of the internal combustion engine, in which the air supply channel is designed as Ansaugsammelrohr. The reasons are those already mentioned above in connection with the previously discussed embodiment.

Also advantageous in certain applications, embodiments of the internal combustion engine, in which the air supply channel is formed as a bypass line of an intake manifold. These are essentially applications in which the air flow in Ansaugsammelrohr should not be disturbed. In particular, use cases are meant in which one would like to have the possibility of completely suppressing the flow through the device for generating negative pressure, as provided, for example, in DE 198 21 686 A1. However, this can only be realized by means of a valve provided in the bypass line. A complete blockage of the air supply channel is prohibited.

Embodiments of the internal combustion engine in which the at least one main vacuum line in the region of the cross-sectional constriction of the first device for generating a negative pressure opens into the air supply channel are advantageous. Background of this embodiment is that the static pressure in the narrowest cross section is lowest, since the flow velocity of the Air flow is the highest, which promotes or supports the provision of the largest possible negative pressure.

With regard to the configuration of the second device for generating a negative pressure, similar preferred embodiments result as in the first device.

Thus, embodiments of the internal combustion engine are advantageous in which the second means for generating a negative pressure is formed as a nozzle having a cross-sectional constriction.

Furthermore, embodiments of the internal combustion engine are advantageous in which the size of the cross-section of the cross-sectional constriction is variable.

Also advantageous are embodiments of the internal combustion engine in which the second device for generating a negative pressure is designed as a Venturi nozzle.

The reasons why the three last-mentioned embodiments of the second negative pressure generating means are advantageous are those mentioned in connection with the description of advantageous embodiments of the first means, and therefore they are not to be repeated here and referred to.

Embodiments of the internal combustion engine in which the second device designed as a nozzle for generating a negative pressure is formed as part of the at least one main vacuum line are also advantageous, in that the outer walls of the nozzle form part of the outer walls of the at least one main vacuum line.

Also advantageous are embodiments of the internal combustion engine, in which the second device designed as a nozzle for generating a negative pressure in the at least one main vacuum line is arranged, in such a way that the nozzle Is surrounded by the main vacuum line, so that the nozzle is internally and externally flowed through by the main vacuum line flowing through the air flow.

Embodiments of the internal combustion engine in which at least one secondary vacuum line is provided, which opens into the at least one main vacuum line and with which a negative pressure in the main vacuum line can be tapped off, are advantageous. About this at least one secondary vacuum line vacuum consumers can be connected and subjected to negative pressure.

Although this embodiment initially appears to be the only sensible, since it follows the procedure that is considered to be expedient in the first device for generating a negative pressure, namely, to tap the negative pressure by means of a vacuum line. But it must be considered that in principle a vacuum consumers can be connected directly to the main vacuum line and is completely dispensed with a secondary vacuum line, wherein - if the second means for generating a negative pressure, for example, is designed as a nozzle - the narrowest cross-section of the nozzle preferably at Junction is arranged to the vacuum consumers, whereby the tapped in the air supply duct vacuum is actually amplified in the main vacuum line.

Furthermore, in each case a consumer can be connected both to the secondary vacuum line and to the main vacuum line. The negative pressure consumer connected to the secondary vacuum line is then subjected to the vacuum boosted according to the invention, while the consumer connected to the main vacuum line is subjected to the vacuum tapped in the air supply duct. In this case, preferably sensitive consumers are connected to the secondary vacuum line, which must be safely supplied under all operating conditions with a sufficiently high negative pressure, because they are - for example - as the brake booster - indispensable for driving safety. To the main vacuum line then less relevant systems would be connected, such as an air conditioner.

According to the invention, both a plurality of main vacuum lines and a plurality of secondary vacuum lines can be provided, which takes into account the fact that an internal combustion engine generally has a plurality of vacuum consumers to be connected.

Embodiments of the internal combustion engine in which the at least one secondary vacuum line in the region of the cross-sectional constriction of the second device for generating a negative pressure opens into the at least one main vacuum line are advantageous. As already mentioned, the static pressure in the narrowest cross-section is lowest or the negative pressure most pronounced.

Advantageous embodiments of the internal combustion engine, in which at least one secondary vacuum line is provided which opens into the air supply channel and with which a negative pressure in this air supply channel can be tapped. This secondary vacuum line differs from a main vacuum line in that it has no second means for generating a negative pressure, so that it is acted upon only with the tapped in the air supply passage negative pressure. At this secondary vacuum line vacuum consumers can also be connected, preferably consumers who only need a low vacuum.

The second of the invention underlying subtask is achieved by a use of the described internal combustion engine for supplying a brake booster, to which the brake booster with the at least one main vacuum line, with the at least one secondary vacuum line, but preferably is connected to the at least one secondary vacuum line.

The second of the invention underlying subtask is also achieved by a use of the described internal combustion engine to power an automatic transmission, an air conditioner, an exhaust gas recirculation system, a tank ventilation, a power steering or the like. The connection of this Systems or vacuum consumers takes place in the same way as described for the brake booster.

What has already been said for the internal combustion engine according to the invention also applies to the use according to the invention. The use of the internal combustion engine according to the invention provides in particular for increased driving safety, which is achieved by providing a sufficiently high negative pressure under all operating conditions of the internal combustion engine.

Fig. 1

schematisch eine erste Ausführungsform in einer Seitenansicht und geschnitten,

Fig. 2a

schematisch eine zweite Ausführungsform in einer Seitenansicht und geschnitten, und

Fig. 2b

schematisch die in Figur 2a dargestellte zweite Ausführungsform entlang des in der Figur 2a kenntlich gemachten Schnittes A-A.

In the following the invention with reference to two embodiments according to Figures 1, 2a and 2b will be described in more detail. Hereby shows:

Fig. 1

schematically a first embodiment in a side view and cut,

Fig. 2a

schematically a second embodiment in a side view and cut, and

Fig. 2b

schematically the second embodiment shown in Figure 2a along the marked in Figure 2a section AA.

Figure 1 shows schematically a section of a first embodiment of the internal combustion engine according to the invention in a side view and cut. Shown here is only the part of the internal combustion engine, which is relevant to the generation of a negative pressure in question here.

Figure 1 shows an air supply channel 1, which has an inlet opening 2 and an outlet opening 3 and which serves to supply an internal combustion engine with combustion air or fresh mixture. For this purpose, an air flow or fresh mixture flow through the inlet opening 2 in the air supply channel 1, wherein the outlet port 3 is connected in the manner of the internal combustion engine that sucked through the air supply duct air or the sucked fresh mixture to a combustion chamber or the combustion chambers of the internal combustion engine is guided (not shown).

In the air supply channel 1, a first means for generating a negative pressure 4 is arranged. In this case, this first device for generating a negative pressure 4 is designed as a nozzle 10. The nozzle 10 has a cross-sectional constriction 12 and is formed in such a way that the nozzle 10 forms part of the air supply channel 1. In this case, the outer walls of the nozzle 10 form part of the outer walls of the air supply channel. 1

This provides advantages in particular in the production of the nozzle 10 and the air supply channel 1. A separate mounting of the nozzle 10 in the air supply channel 1 is omitted. The airflow entering through the inlet port 2 is accelerated in the nozzle 10, the static pressure decreasing with increasing cross-sectional constriction. In the smallest section, the static pressure is lowest.

In the region of this cross-sectional constriction 12 of the nozzle 10, a main vacuum line 5 4 opens into the air supply duct 1 or into the nozzle 10, with which a negative pressure setting in the cross-sectional constriction 12 during operation of the internal combustion engine can be tapped. In the main vacuum line 5, a second device for generating a negative pressure 6 is arranged, wherein this second device 6 is formed as a nozzle 11 having a cross-sectional constriction 13. The tapped by means of the main vacuum line 5 vacuum is in this way - in a sense in a two-step process - amplifies verst and the vacuum consumers available.

The vacuum consumers can be connected to the main vacuum line 5 and / or to the secondary vacuum line 7, which opens into the main vacuum line 5. In the embodiment shown in FIG. 1, the secondary vacuum line 7 opens into the main vacuum line 5 in the region of the cross-sectional constriction 13 of the second device for generating a negative pressure 6.

Optionally, a secondary vacuum line 8 are provided (shown in dashed lines) to which also vacuum consumers can be connected and in the illustrated embodiment - as the main vacuum line 5 - in the region of the cross-sectional constriction 12 of the nozzle 10 into the air supply channel 1 and the nozzle 10 opens ,

This secondary vacuum line 8 can also be equipped with a device for generating a negative pressure and then serve as a second main vacuum line to amplify the tapped in the nozzle 10 negative pressure.

In principle, a plurality of main vacuum lines 5, a plurality of secondary vacuum lines 8 and / or a plurality of secondary vacuum lines 7 can be provided, which leads to further embodiments of the internal combustion engine according to the invention. The number of these lines can be adapted to the number of vacuum consumers to be supplied.

Figure 2a shows schematically a section of a second embodiment of the internal combustion engine according to the invention in a side view and cut. Figure 2b shows this second embodiment along the section A-A, which is indicated in Figure 2a. Only the differences from the embodiment shown in Figure 1 will be discussed, for which reason reference is otherwise made to Figure 1. For the same components, the same reference numerals have been used.

In contrast to the embodiment shown in FIG. 1, in the embodiment illustrated in FIGS. 2 a and 2 b, the first device designed as a nozzle 10 for generating a negative pressure 4 is arranged in the air supply channel 1. The nozzle 10 is surrounded by the air supply channel 1, so that the nozzle 10 is flowed through inside and outside of the air flow flowing through the air supply channel 1.

For this purpose, the nozzle 10 by means of struts 9a ', 9a ", 9b', 9b", 9c ', 9c ", 9d', 9d" fixed to the inner wall of the air supply channel 1. In this way, not all of the air flow passage through the air supply channel 1 is passed through the nozzle 10 and constricted, but only a more or less small partial flow. The remaining part of the air flow is passed outside the inner wall of the air supply duct 1 and nozzle 10 to the nozzle 10 and remains - apart from the struts 9a ', 9a ", 9b', 9b", 9c ', 9c ", 9d', 9d" - almost unaffected.

This offers advantages, for example, with large air mass flows, as they are set at high speeds, since then the constriction of the flow cross-section of the air supply channel 1 is to be regarded as increasingly disturbing.

reference numeral

1

Air supply duct

2

inlet port

3

outlet

4

first device for generating a negative pressure

5

Main vacuum line

6

second device for generating a negative pressure

7

In addition to vacuum line

8th

secondary vacuum line

9a '

strut

9a "

strut

9b '

strut

9b "

strut

9c '

strut

9c "

strut

9d '

strut

9d "

strut

10

jet

11

jet

12

Cross-sectional narrowing

13

Cross-sectional narrowing

Claims (22)

1. Internal combustion engine having an air feed duct (1) and a first vacuum-generating device (4), which is arranged in this air feed duct (1) and which generates a vacuum by utilizing energy components of the air flow passing through the air feed duct (1), the internal combustion engine being equipped with at least one main vacuum line (5), which opens into the air feed duct (1) and by means of which a vacuum in this air feed duct (1) can be tapped, characterized in that a second vacuum-generating device (6), which generates a vacuum by utilizing energy components of the air flow passing through at least one main vacuum line (5) is arranged in at least one main vacuum line (5).
2. Internal combustion engine according to Claim 1, characterized in that the first vacuum-generating device (4) is configured as a nozzle (10) having a narrowed cross section (12) .
3. Internal combustion engine according to Claim 2, characterized in that the size of the narrowed cross section (12) is variable.
4. Internal combustion engine according to any one of the preceding claims, characterized in that the first vacuum-generating device (4) is configured as a venturi nozzle (10).
5. Internal combustion engine according to any one of Claims 2 to 4, characterized in that the first vacuum-generating device (4) configured as a nozzle (10) forms a part of the air feed duct (1), in such a way that the outside walls of the nozzle (10) form a part of the outside walls of the air feed duct (1).
6. Internal combustion engine according to any one of Claims 2 to 4, characterized in that the first vacuum-generating device (4) configured as a nozzle (10) is arranged in the air feed duct (1), in such a way that the nozzle (10) is enclosed by the air feed duct (1), so that the air flow flows inside and outside the nozzle (10).
7. Internal combustion engine according to any one of the preceding claims, characterized in that the air feed duct (1) is configured as an inlet manifold.
8. Internal combustion engine according to any one of Claims 1 to 6, characterized in that the air feed duct (1) is configured as a bypass line of an inlet manifold.
9. Internal combustion engine according to any one of Claims 2 to 8, characterized in that at least one main vacuum line (5) opens into the air feed duct (1) in the area of the narrowed cross section (12) of the first vacuum-generating device (4).
10. Internal combustion engine according to any one of the preceding claims, characterized in that the second vacuum-generating device (6) is configured as a nozzle (11) having a narrowed cross section (13).
11. Internal combustion engine according to Claim 10, characterized in that the size of the narrowed cross section (13) is variable.
12. The internal combustion engine according to any one the preceding claims, characterized in that the second vacuum-generating device (6) is configured as a venturi nozzle (11).
13. Internal combustion engine according to any one of Claims 10 to 12, characterized in that the second vacuum-generating device (6) configured as a nozzle (11) forms a part of at least one main vacuum line (5), in such a way that the outside walls of the nozzle (11) form a part of the outside walls of at least one main vacuum line (5).
14. Internal combustion engine according to any one of Claims 10 to 12, characterized in that the second vacuum-generating device (6) configured as a nozzle (11) is arranged in at least one main vacuum line (5), in such a way that the nozzle (11) is enclosed by the main vacuum line (5), so that the air flow passing through the main vacuum line (5) flows inside and outside the nozzle (11).
15. Internal combustion engine according to any one of the preceding claims, characterized in that at least one auxiliary vacuum line (7) is provided, which opens into at least one main vacuum line (5) and which is capable of tapping a vacuum in the main vacuum line (5).
16. Internal combustion engine according to Claim 15, characterized in that at least one auxiliary vacuum line (7) opens into at least one main vacuum line (5) in the area of the narrowed cross section (13) of the second vacuum-generating device (6).
17. Internal combustion engine according to any one of the preceding claims, characterized in that at least one secondary vacuum line (8) is provided, which opens into the air feed cut (1) and which is capable of tapping a vacuum in this air feed duct (1).
18. Use of an internal combustion engine according to any one of the preceding claims for supplying a vacuum to a device, characterized in that the internal combustion engine is used to supply a brake booster, for which purpose the brake booster is connected to at least one main vacuum line (5), to at least one auxiliary vacuum line (7), or to at least one secondary vacuum line (8).
19. Use of an internal combustion engine according to any one of Claims 1 to 17 for supplying a vacuum to a device, characterized in that the internal combustion engine is used to supply an automatic transmission, for which purpose the automatic transmission is connected to at least one main vacuum line (5), to at least one auxiliary vacuum line (7), or to at least one secondary vacuum line (8).
20. Use of an internal combustion engine according to any one of Claims 1 to 17 for supplying a vacuum to a device, characterized in that the internal combustion engine is used to supply an air conditioning system, for which purpose the air conditioning system is connected to at least one main vacuum line (5), to at least one auxiliary vacuum line (7), or to at least one secondary vacuum line (8).
21. Use of an internal combustion engine according to any one of Claims 1 to 17 for supplying a vacuum to a device, characterized in that the internal combustion engine is used to supply an exhaust gas recirculation system, for which purpose the exhaust gas recirculation system is connected to at least one main vacuum line (5), to at least one auxiliary vacuum line (7), or to at least one secondary vacuum line (8).
22. Use of an internal combustion engine according to any one of Claims 1 to 17 for supplying a vacuum to a device, characterized in that the internal combustion engine is used to supply a tank ventilation system, for which purpose the tank ventilation system is connected to at least one main vacuum line (5), to at least one auxiliary vacuum line (7), or to at least one secondary vacuum line (8).

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