DE102007052310A1 - Internal-combustion engine, particularly externally ignited internal-combustion engine, has multiple cylinders, air suction unit, compressor for promotion of combustion air, and combustion chamber arranged in cylinder - Google Patents

Abstract

The internal-combustion engine has multiple cylinders, an air suction unit (3), a compressor for promotion of the combustion air, and a combustion chamber arranged in the cylinder. The air suction unit is formed in such a manner that a part of air mass flows into the combustion chamber of the internal-combustion engine during expansion phase of air mass in the air suction unit.

Description

The The invention relates to an internal combustion engine, in particular a spark-ignited Internal combustion engine, with a compressor according to the Preamble of claim 1.

At the Operation of internal combustion engines are usually air suction systems using a vibratory or resonant tube charge or to achieve a combination of these two charges. In a charged Internal combustion engine is due to the compression of the intake combustion air an increase in the air temperature. The coveted for naturally aspirated engines Charging effect by vibration tube charging or resonance charging is undesirable, especially in turbocharged gasoline engines, because the charge air is heated by the gas-dynamic compression and thereby increasing the propensity for knocking combustion.

To avoid further charging, a charge air cooler for cooling the charge air is therefore positioned behind the compressor in charged diesel and gasoline engines. This should, especially in turbocharged gasoline engines, the risk of a knocking engine can be minimized. A further reduction of the charge air temperature is not possible by an enlarged intercooler usually for structural reasons. Accordingly, to increase the efficiency of the charge air cooler downstream of this relaxation facilities are provided to further reduce a combustion air temperature. From the DE 100 02 482 A1 For example, such a device for intercooling is known, in which the standing under increased boost pressure combustion air is released at a back pressure valve. The backflow valve is positioned between the intercooler and the air intake of the engine.

From the DE 36 27 312 A1 For example, in order to reduce the charge air temperature, a relaxation control device is known with which an adiabatic partial relaxation of the charged air is achieved. In this case, the expansion control device has a nozzle-like line section, which is designed in the manner of a Laval nozzle, wherein the nozzle-like line section is arranged in the intake pipe in front of the air suction. The known from the prior art measures for cooling the charge air after exiting the intercooler require the arrangement of a relaxation device in the intake and thus cause additional structural complexity in the engine compartment of the vehicle.

Of the Invention is therefore based on the object, a supercharged internal combustion engine to provide an optimized air intake are achieved can. This is inventively by a device solved with the features of claim 1.

The inventive internal combustion engine is characterized characterized in that the air suction system is designed such that the air intake into the combustion chamber during an expansion phase the air mass takes place in the air suction system. Accordingly flows at least part of the air mass into the combustion chamber during the expansion phase. The charge air expansion is partially in plenary, in the respective intake manifold and / or inside the distributor pipe instead of. According to the invention, a continuous, but not necessarily even, expansion between the entry of combustion air into the manifold until it flows the combustion air into the combustion chamber, d. h., until the exit the suction tube, achievable.

According to the invention the air suction on such a manifold tube length, that the air intake into the combustion chamber of the internal combustion engine during an expansion phase of the air mass takes place in the Luftsauganlage. Preferably, the manifold tube length is dimensioned such that At the time of air intake, a reduction of the boost pressure can be achieved within the Luftsauganlage. With the invention Design of the air intake, in particular the design of the Manifold tube length, will resonant effects at maximum engine power avoided, and in addition allows an air intake, with which a targeted and tailored to the intake timing expansion brought about becomes.

By the inventive design of the air suction A method for air intake is made possible with the at the time of air intake, the temperature of the respective Cylinder sucked air mass between the plenum and the combustion chamber the internal combustion engine is reduced. Preferably, a Reduction of the air mass temperature below a mean temperature value. The temperature values fluctuate around such a mean temperature value the air mass inside the air intake system. Such a mean temperature Adjusts approximately at the manifold center.

The Air suction system according to the invention is distinguished characterized in that the distributor tube length in dependence of an equivalent manifold diameter is. As a result, the oscillating air in the Luftsauganlage during the cooler expansion phase into the respective combustion chamber sucked so that a relatively low temperature of the fuel / air mixture present in the combustion chamber.

With the inventive design of the air suction is the effective expansion due to the achieved expansion the charge air inside the air intake without the use of additional moving Causes components. This will be a cost effective and efficient air intake system for supercharged internal combustion engines provided, wherein the inventive Expansion air intake system for both charged Otto and also suitable for diesel engines.

In An embodiment of the invention is the manifold tube length as a function of a rated speed of the internal combustion engine sized. Thus, the present air suction is charged with Engine optimally used and a targeted vote, especially for sports vehicles, for higher load points and speeds possible.

With the air suction system according to the invention decreases Temperature of the aspirated air mass in the plenum below the mean value during a crank angle range between 90 ° after the upper charge cycle dead center and 20 ° after the lower charge cycle dead center. This allows more than 20 ° temperature reduction be achieved. Consequently, a significant shift of the ignition angle allows for early, so that the efficiency the internal combustion engine improved. Due to the earlier ignition timing decreases the exhaust gas temperature, leaving a need for enrichment for protection the exhaust gas turbine is lower. As a further consequence of the efficiency improvement will charge less for the same engine power and Fuel is needed, reducing the entire charging process the internal combustion engine is optimized.

To Another aspect of the invention, the formation of the Manifold tube length depending on the equivalent Distributor tube diameter such that a ratio of equivalent Manifold tube diameter to manifold tube length of 0.05 to 0.14 is present. The suction tube length should not more than 200 mm or 150 mm, especially at rated speed be rated between 5500 and 7000 revolutions per minute. Vorzugesweise is the ratio of equivalent Manifold tube diameter to manifold tube length 0.066, 0.114 or 0.136. This results in an optimized within the air suction Expansion of the compressed combustion air, so that the Combustion air from the air intake with a much lower Temperature in the inlet channel flows in the cylinder head.

By the novel geometric determination of the distributor tube of the air suction system is compared to the usual suction a manifold with a small diameter in front, so the construction effort is optimized in the engine compartment. The inventive Air suction system returns through the invention Dimensioning the known resonance charging effect, especially at high engine speeds, completely over. Instead of compression will achieved an expansion of the combustion air and this cooled further. Thus, there is a lower temperature of the fuel / air mixture in the combustion chamber before, so that the ignition timing of the internal combustion engine is optimal performance adjustable.

In A further embodiment of the invention, the internal combustion engine one or two rows of cylinders, with the number of cylinders a total of six. According to the invention has been in a spark-ignited 6-cylinder internal combustion engine the boxer model showed that the present air intake system too leads to a significant improvement in efficiency. Yet The present air suction system is also suitable for Internal combustion engines with four cylinders.

In An embodiment of the invention provides the present invention to further improve the cylinder filling, in particular in supercharged spark-ignition internal combustion engines, a additional increase of the boost pressure by the Compressor in front of the reduced boost pressure through the within the air suction system to compensate for expansion. Preferably is at the same engine power a higher boost pressure 3 to 10% set as the usual boost pressures. The usual charge pressures are in between 0.9 bar and 1.5 bar.

By a higher set boost pressure rises after the compressor the combustion air temperature, so that through the higher Set temperature level of the combustion air in the intercooler a larger amount of heat dissipated becomes. According to the invention is a higher Temperature difference over the intercooler to about 3 to 10% than in conventional charging pressures. This results in a combustion air temperature after the intercooler which is only slightly higher than the with a conventional or conventional charging, as the amount of heat removed from the intercooler Up to 55% higher than normal boost pressure conditions. The here by the use of the invention Air intake additionally achieves thermal gain leads to a lower temperature of the fuel / air mixture in the combustion chamber, because both the pressure and the temperature level in the combustion chamber to the intake valve closing timing is between 3 and 4% lower is lower than normal air suction systems. Consequently, at a Sports vehicle with a supercharged engine, especially at high Load points and speeds, with the same engine power a cheaper Fuel consumption or a higher engine power at the same Fuel consumption can be achieved.

In a further advantageous embodiment of the invention takes place in the internal combustion engine according to the invention the use of an exhaust gas turbocharger with an adjustable turbine geometry in connection with the expansion air intake system according to the invention a constant adaptation of the achieved expansion of the combustion air within the air intake system to the operating condition of the engine. hereby can in the internal combustion engine according to the invention an optimization of the ignition timing and therefore another Efficiency improvement can be achieved.

Further Features and feature combinations result from the description. Concrete embodiments of the invention are shown in the drawings shown simplified and in the following description in more detail explained. Showing:

1 1 shows an illustration of an air intake system according to the invention of a supercharged internal combustion engine with cylinders arranged in two rows,

2 a schematic representation of the air intake after 1 according to a first embodiment,

3 a schematic representation of the air intake after 1 according to a second embodiment,

4 1 is a schematic representation of an air suction system according to the invention of an internal combustion engine with cylinders arranged in a row according to a third exemplary embodiment,

5 a schematic representation of the air intake after 4 according to a fourth embodiment,

6 a schematic representation of the air intake after 1 according to a fifth embodiment,

7 a schematic representation of the air intake after 4 according to a sixth embodiment,

8th a schematic diagram of the pressure, temperature and mass flow curve within the Luftsauganlage the internal combustion engine according to the invention,

9 a schematic illustration of the dimensional ratios of the air suction system of the internal combustion engine according to the invention,

10 a schematic representation of the charge temperature in the combustion chamber of an internal combustion engine,

11 a schematic representation of the effect of the air suction after 1 on the engine power of an internal combustion engine,

12 a schematic representation of the temperature values of the cylinder charge in the combustion chamber of an internal combustion engine according to the invention at the time "intake valve closes" in dependence on the set speed,

13 a mass flow and temperature profile in the manifold of the air intake after 1 at a time prior to the charge cycle dead center,

14 a mass flow and temperature profile in the manifold of the air intake after 1 at a time after the charge cycle dead center,

15 a mass flow and temperature profile in the manifold of the air intake after 1 at a time between charge cycle dead center and bottom dead center and

16 a mass flow and temperature profile in the manifold of the air intake after 1 at bottom dead center.

An internal combustion engine 1 with charge has at least one cylinder 2 on, in which an unillustrated combustion chamber between one in the cylinder 2 formed longitudinally displaceable piston and a cylinder head is formed. The internal combustion engine 1 sucks combustion air through a compressor 8th at. The charging of the internal combustion engine 1 can according to the invention by a compressor 8th come about, which is designed as part of an exhaust gas turbocharger, a mechanical compressor or an electric compressor. Compressing the combustion air increases the charge air temperature. To reduce this is the compressor 8th a charge air cooler 9 downstream.

In 1 is an air suction system designed according to the invention 3 shown in the charge air in a manifold 4 through an air duct 5 is encouraged. In the 1 illustrated air suction system 3 is for an internal combustion engine 1 formed with two rows of cylinders such that for each row of cylinders an intake manifold or plenum 6 is provided. The air supply takes place in the middle of the distributor pipe 4 , There is a non-illustrated throttle body flanged. It is at every plenum 6 three suction pipes 7 per cylinder row provided over the charge air not darge inlet channel in the cylinder head and then the combustion chamber can be fed. Both plenen 6 are on a central manifold 4 connected. Here is the plenum 6 with the suction pipes 7 integrally formed. According to the present invention is between the two plenen 6 a manifold 4 arranged, in the present embodiment of a distributor module 4a and from two pipe sections 4b is formed, which are formed integrally with the respective plenum. The connection can be made by means of band clamps or with a bayonet-like closure.

According to the invention, a distributor tube length L _{V is} dimensioned as a function of an equivalent distributor tube diameter D _V such that a reduction of the charge pressure of the combustion air within the air suction system 3 by a targeted expansion takes place, wherein the expansion takes place partly in the plenum and / or within the manifold. According to the invention, the expansion takes place in a range between an entry of the combustion air into the manifold 4 , z. B. from the distributor module 4a , and an exit from the suction pipe 7 instead of. Depending on the firing order of the respective cylinder 2 occurs within the Luftsauganlage on a vibration, wherein the expansion of the charge air to the respective combustion chamber referred to continuously within the Luftsauganlage, but not necessarily uniform, can be achieved. As a result, the charge air temperature can be lowered when entering the combustion chamber and thus the fuel / air mixture temperature in the combustion chamber, so that the engine power can be increased while lowering the specific fuel consumption.

According to the present invention, the oscillating air in the Luftsauganlage 3 sucked during the cooler expansion phase for the mixture preparation, whereby the temperature of the fuel mixture in the combustion chamber is reduced. This leads to a significant increase in efficiency. For example, at maximum power of a six-cylinder boxer engine, fuel economy reduction of about 15% is achieved.

The present invention is characterized in that the expansion suction system described here 3 for internal combustion engines 1 good with six or four cylinders. For a turbocharged six-cylinder engine, the manifold tube length L _V shall be determined by the following formula: 200 - 4/3 · L S + 1.7 n N -2.22 · (D V - 30) <L V <7.2 · 10 6 / n N - 1.5 · L S

For a turbocharged four-cylinder engine, the range for the manifold tube length L _V in which the expansion aspirator can achieve beneficial results is determined by the formula: 34 · D V - 650 - 4/3 · L S <L V

In this case, L _S corresponds to a suction pipe length between the plenum 6 and the cylinder head, not shown. The value L _V stands for the manifold tube length, which is to be determined differently depending on the embodiment. L _V is the tube length of the connecting tube between the first and the second plenum 6 , In the embodiments with the container 4c respectively. 11 according to 3 respectively. 5 L _{V is} the sum of the distribution pipe sections L _V = L _V1 + L _V2 . Further, n _N corresponds to a rated engine speed at which maximum power is achieved.

In a manifold 4 with variable cross-sectional area A _V (x), the internal volume V _{V of} the connecting pipe shall be determined by the following formula: V V = ∫A V (x) dx, where A M = V V / L V

Where x is the path coordinate along a pipe centerline. Areas where A _V (x) is greater than twice the average cross-sectional area AM are considered not as a pipe but as a container and are not included in the calculations of the pipe length L _V and the equivalent pipe diameter D _V.

This results in the equivalent connecting tube diameter D _V according to the formula:

In the first embodiment according to 2 the distributor tube length L _{V is} equal to the distance between the two plenums 6 to put. In the second embodiment according to 3 the distributor tube length L _{V is} composed of the lengths of the two sections L _V1 and L _V2 , wherein in the third embodiment according to 4 the manifold tube length of the arc length of the manifold 4 equivalent. In the fourth embodiment according to 5 the distributor tube length L _{V is} composed of the two section lengths L _V1 and L _V2 . In the fifth embodiment is according to 6 manifold length L _V equals the distance between the two plenums 6 to set, wherein in the sixth embodiment according to 7 the manifold tube length of the arc length of the manifold 4 equivalent.

According to the invention result in a design of the expansion suction 3 on the basis of the above formula advantageous low temperatures at the inlet opening of the combustion chamber. In particular, with a manifold tube length of about 440 mm and an equivalent manifold through diameter D _V of 50 or 60 mm or between 50 and 60 mm, high degrees of expansion can be set. This point, the suction pipes 7 a length L _S , which is below 200 or 150 mm, preferably between 110 and 140 mm. Accordingly, the design of the distributor tube length L _V as a function of the equivalent distributor tube diameter D _V is to be selected such that a ratio of equivalent distributor tube diameter D _V to distributor tube length L _{V is} in a range of 0.05 to 0.14, in particular in a range of 0 , 06 to 0.13. In the case of a six-cylinder engine, it has been shown that ratios of 0.066, 0.114 or 0.136 or ratios lying between these values have led to optimum results in the sense of the present invention, in particular if the intake pipe length L _{S is} shorter than 150 mm.

The internal combustion engine described here 1 operates on the four-stroke principle, wherein the present invention is also suitable for two-stroke internal combustion engines. The longitudinal movement of the piston extends between a top dead center OT and a bottom dead center UT. In the first intake stroke of the four-stroke internal combustion engine 1 is the combustion chamber through an inlet channel or a suction pipe 7 Combustion air supplied, wherein the piston moves in a downward movement from a charge cycle dead center LW-TDC to a lower charge exchange dead center UT. In a subsequent compression stroke, the piston moves in an upward movement up to an upper ignition dead center ZOT, around which the ignition is made. Thereafter, the piston expands in a downward movement to a bottom dead center, wherein in a last cycle of the piston in an upward movement up to an upper charge exchange dead center LW-OT expels the gases from the combustion chamber.

In the 2 Plenen shown 6 are with the manifold 4 connected, this manifold 4 is formed such that the combustion air is supplied to the respective combustion chamber at a time to which in plenary 6 a charge air pressure prevails, which is lower than the charge air pressure in the air duct 5 prevails. To clarify the effect achieved by the invention Luftsauganlage 3 are in 8th some air statuses in plenary 6 or in the intake manifold 7 the internal combustion engine 1 shown. The curve for the settling tank represents an idealized state of the art. This system is designed with a very large intake volume such that no pressure oscillations occur within the intake system. Here is such a system for evaluation, as it usually out of package, weight and Fahrbarkeitsgründen for practice rarely comes into question.

The dimensions of the opposed Luftsauganlagen according 8th were chosen to better illustrate the characteristic features so that the typical differences stand out particularly clearly. The selected diameter of the resonance tube of the used for comparison resonance suction is 120 mm, the tube length was tuned for 6000 l / min. The suction tank or plenen 6 correspond to those of a sports car with six cylinders. The suction tubes were assumed to be the same and extremely short with 50 mm length in all three examples.

In the upper diagram in 8th are the pressure gradients in plenary 6 to 13 to 16 shown. When sucking in from the settling tank with a volume of about 15 liters virtually no pressure amplitudes occur. The constant pressure in the tank marks the boost pressure. In the case of resonance charging, the charge pressure P, that is to say the time-averaged value, is lower by approximately 0.25 bar, because the resonance charge is added for charging by the compressor. In the expansion suction system, the boost pressure P is about 0.25 bar above that of the calming tank system and 0.5 bar above that of the resonance system. The pressure amplitudes are significantly higher than known from naturally aspirated engines, as due to the higher density of the charge air correspondingly more mass between the plenen 6 swings.

According to 8th The phase angles of the pressure oscillation differ by approx. 70 ° crank angle. Nevertheless, up to 90 ° phase difference is possible due to other geometries. Due to the phase position of the pressure P, different mass flow characteristics are established at the inlet. If one compares, for example, the mass flow curve with the temperature profile in plenum 6 the cylinder bank row 1-2-3 according to 8th respectively. 13 to 16 , it can be seen that in the Expansionssauganlage during 120 degrees crank angle of 90 degrees after the upper charge cycle dead center LW-OT to 20 degrees after the lower charge exchange dead center UT, the temperature in plenary 6 below its mean T _medium sinks.

The result is finally reflected in the temperature profile T _B in the combustion chamber of the first cylinder. Compared to the tranquilizer suction system, which is intended to represent the idealized state of the art, a temperature reduction of more than 20 degrees is achieved. This effect allows according to 10 in conventional engine designs a significant shift of the ignition angle to early. This improves the high-pressure efficiency, the engine power increases accordingly 11 , With earlier ignition, the exhaust gas temperature drops, so that the Anfettungsbedarf to protect the exhaust gas turbine is lower.

As in the upper diagram 8th is shown, a maximum valve lift at the inlet in a second half of the intake stroke is set, ie, between the upper charge cycle dead center LW-OT and the bottom dead center UT. As in the middle diagram in 8th is shown, the temperature of the combustion air in the second half of the intake stroke by the expansion in plenum 6 a minimum temperature value T _min . The present invention is characterized in that the air suction system according to the invention 3 is designed such that at the time of combustion air intake within the Luftsauganlage 3 especially in plenary 6 as well as in the suction pipes 2 , a gas-dynamic expansion prevails. As a result, the combustion air substantially at a low temperature T _min when the combustion air flows into the combustion chamber.

According to 3 a second embodiment is shown, in which in the middle of the manifold 4 instead of the distributor module 4a a container 4c is provided. According to this embodiment, the manifold tube length L _{V is} composed of the distances between the respective plenum 6 and the container 4c lie. According to a third embodiment according to 4 has the internal combustion engine according to the invention 1 also six cylinders, which are arranged in series. Here is the air suction 3 formed such that the combustion air is divided so that for the three front cylinder 2a a first plenum 6a is provided, wherein for the remaining three cylinders 2 B a second plenum 6b is provided. For this purpose, the manifold 4 arcuate, wherein the manifold tube length L _V corresponds to the arc length. According to the invention, the manifold 4 depending on the cylinder arrangement and engine design within the scope of the invention in any conceivable form, for. B. arcuate, straight or square or as a combination of different shapes, be formed.

A modified form of the third embodiment is shown in FIG 5 illustrated according to a fourth embodiment, in which case the manifold 4 is divided into two sections, being between the air duct 5 and the respective distributor pipe sections 10 a container 11 is positioned. In this embodiment, the manifold pipe length L _{V is} composed of the two manifold pipe section lengths L _V1 and L _V2 .

According to a fifth embodiment of the invention according to 6 is between the plenums 6 an additional manifold 12 arranged, by a switching element, here as a flap 13 trained, can be switched on depending on the engine parameters. By in the additional manifold 12 arranged switching flap 13 the size of the equivalent distributor diameter D _{V is} adjustable. As a result, the achievable expansion of the charge air as a function of the speed of the internal combustion engine 1 be set. The arrangement of an additional manifold 12 with a switching flap 13 is also conceivable in all previously described embodiments. Depending on the shape of the distributor pipe, one or two additional distributor pipes are used 12 in the appropriate places to adjust the size of the equivalent distribution diameter D _V to position. In the 7 Illustrated sixth embodiment illustrates a modified form of the fifth embodiment 4 represents.

In 12 are exemplary curves of the charge temperature T _B in the combustion chamber after the end of the inflow of the expanded charge air is shown in the combustion chamber. In the three pictures out 12 are different temperature values as a function of the speed of the internal combustion engine 1 shown. Thus, through the additional switchable manifold 12 depending on the operating parameters of the internal combustion engine, such as the rotational speed, set a certain equivalent distributor diameter D _V , and thus a coordinated expansion of the charge air can be achieved. Accordingly, the setting of a lowest temperature of the charge air at the time of entry into the combustion chamber in dependence on the operating parameters is made possible, so that an optimal efficiency at the respective operating point of the internal combustion engine 1 is present.

The expansion suction system according to the invention 3 and their configuration is explained in more detail below with further details. The schematic representation of in 9 illustrated dimensional ratios of the air suction 3 to 1 are based on the temperature curves of the charge air in 12 derived. Here are the in 9 displayed triangles the temperature ranges with the low temperature values of the charge air 12 Here, the distributor tube length L _{V is} to be selected as a function of the equivalent distributor tube diameter D _{V in} such a way that an intersection within one of the in 9 shown triangles results. With such an interpretation results in the invention Expansionssauganlage 3 at the inlet of the combustion chamber, a charge air temperature T _Min , which is lower than a mean temperature T _medium .

The geometric design of the air suction system 3 leads to such a charge-air expansion, that the expansion phase of the charge air oscillation in the second half of the second intake according to 8th , upper diagram, lies. In the second half of the suction come in accordance 8th During the expansion phase, the lowest temperature values of the charge air are achieved. Due to the relatively cold sucked air masses results then according to the invention a combustion chamber cylinder filling with a relatively lower temperature. This effect causes a shift of the knock limit toward early according to 11 so that a previous ignition is possible.

Consequently, the engine output can be increased by the ignition timing of the internal combustion engine 1 is set earlier than with a warmer cylinder filling. This leads to a significant performance gain. It is conceivable by the lower knock tendency achieved an increase in the compression ratio of the internal combustion engine.

To the achieved expansion in the air suction system 3 Compensate is through the compressor 8th set an adjusted boost pressure, which is higher than in conventional supercharged internal combustion engines. An increase in the boost pressure with the existing expansion suction system 3 For example, it can be between 0.15 and 0.3 bar higher than conventional suction systems. By such a boost pressure increase results in a charge air temperature increase by about 10 degrees before the intercooler 9 , wherein after the intercooler 9 a charge air temperature increase of about 2 to 3 degrees is measured. Accordingly, the set expansion causes a further reduction of the charge air temperature, so that at the inlet of the combustion chamber while maintaining the desired boost pressure level, a low charge air temperature than the usual temperatures 8th and 10 is present. Therefore, the higher air flow rate is maintained in the combustion chamber and at the same time an increase in performance by shifting the knock limit of the internal combustion engine 1 according to 10 and 11 achieved.

The present invention is based on the Luftsauganlage 3 for a six-cylinder engine with two cylinder banks explained in detail. Compared to a classic intake system with such a motor is the manifold 4 the air suction system 3 longer and smaller in diameter, with the individual suction tubes 7 are shorter.

With the present invention, the air intake system of the invention reverses the resonance charging effect at higher engine speeds, so that expansion is utilized instead of compression. Due to this expansion within the air suction system 3 the air is expanded. As a result, the air is cooled, so that a lower temperature of the fuel-air mixture in the combustion chamber is achieved. This makes it possible to ignite the cooler fuel-air mixture optimized performance.

According to 8th in the case of resonance charging, the charge pressure, ie the value determined over time, is lower by about 0.25 bar, because the resonance charging is added to the charge through the compressor. In the air suction system according to the invention 3 By contrast, the boost pressure is about 0.25 bar above that of the contact tank system and 0.5 bar above that of the resonance system. The pressure amplitudes are significantly higher than those of the naturally aspirated engines, as a result of the higher density of the charge air correspondingly more mass between the plenums 6 swings. The phase angles of the pressure oscillations differ by approx. 70 ° crank angle. Due to the phase position of the pressure, different mass flow curves at the inlet in accordance with the lower diagram in 8th one. In the middle diagram in 8th is to be seen that in the air suction system according to the invention 3 the temperature in plenary 6 below the mean T _medium decreases. This effect becomes apparent in the course of the temperature, where the temperature decrease is more than 20 ° during an intake phase between 90 ° crank angle after the charge cycle dead center and 20 ° crank angle after the bottom dead center.

In the 13 to 16 is the spatial waveform, as in the Luftsauganlage invention 3 occurs. Here, the mass flow in the manifold and in the respective intake manifolds of a cylinder bank is shown. During engine operation, the air mass oscillates within the air intake system 3 around the manifold center due to the staggered opening and closing of the intake valves. Accordingly, the air mass oscillates between the two plenums 6 back and forth around the manifold center. The different path positions at the right end of the 13 to 16 arise from the different run lengths through the plenum 6 the cylinder bank, here the cylinders 1, 2 and 3. For reasons of illustration, the cylinder bank 1-2-3 in the 13 to 16 shown on the right. D. h., The observer looks against the direction of travel A of the vehicle. The path shown begins at zero at a transition B from the plenum 6 The opposite cylinder bank, here the cylinder 4, 5 and 6. The introduction of the charge air through a throttle body therefore takes place in the middle of the manifold, ie at a distance of 0.22 meters. According to 13 then the charge air flows everywhere in the direction of the cylinder bank 1-2-3, the figure in 13 represents a momentary recording, which corresponds to a time shortly before the charge cycle dead center LW-OT. The representation in 14 is also a snapshot compared to the 13 a piston position corresponds to the 60 ° crank angle later than the off 13 ,

In addition, in 15 also shown an instantaneous view, which corresponds to a time at which the piston is between the charge cycle and the bottom dead center. In this illustration according to 15 is the Air intake process for the cylinder No. 1 shown, in which case the air intake between the time of maximum piston speed and shortly before reaching a maximum intake valve. At this time, the charge air oscillates in the intake system in the direction of the opposite cylinder bank to cylinder No. 6. In the internal combustion engine shown here is a firing order 1, 6, 2, 4, 3 and 5 before. Accordingly, in the intake manifold 7 of the cylinder No. 1 the air is pulled to the right, so that the charge air in plenary 6 expanded. This results in an air temperature of more than 20 ° below the average T _means according to 16 , According to the 13 to 16 FIG. 4 shows four time recordings within one cycle of the charge air oscillation with a 240 ° crank angle oscillation period. This results from the fact that the present internal combustion engine passes through three cycles per four-stroke cycle within 720 ° crank angle. By the air suction system according to the invention 3 a significant reduction in temperature of the charge air is achieved below the average T _means .

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 10002482 A1 [0003]
• - DE 3627312 A1 [0004]

Claims (17)

Internal combustion engine ( 1 ) with several cylinders ( 2 ), an air suction system ( 3 ), a compressor ( 8th ) for the promotion of the combustion air, and one in the cylinder ( 2 ) arranged combustion chamber, which is delimited between a piston and a cylinder head, wherein - the air suction system ( 3 ) from at least one distributor tube ( 4 ), several suction pipes ( 7 ) and at least one plenary session ( 6 ), the plenum ( 6 ) between the manifold ( 4 ) and the suction pipes ( 7 ), wherein - the combustion air to the air intake system ( 3 ) via an air duct ( 5 ), which enters the distributor pipe ( 4 ), and - the charge pressure (p) of the combustion air after exiting the compressor ( 8th ) until entry into the combustion chamber of the internal combustion engine ( 1 ), characterized in that - the air suction system ( 3 ) is formed such that at least a portion of the air mass into the combustion chamber of the internal combustion engine ( 1 ) flows during an expansion phase of the air mass in the Luftsauganlage. Internal combustion engine ( 1 ) according to claim 1, characterized in that a distributor tube length is dimensioned such that at the time of air intake, a reduction of the boost pressure (P) within the air intake system ( 3 ) is achievable. Internal combustion engine ( 1 ) according to claim 1 or 2, characterized in that at the time of air intake, the temperature of the sucked by the respective cylinder air mass between the plenary ( 6 ) and the combustion chamber of the internal combustion engine ( 1 ) is reduced. Internal combustion engine ( 1 ) according to claim 3, characterized in that the reduction of the air mass temperature below the average temperature (T _medium ) during a crank angle range between 50 ° after the upper charge exchange dead center (LW-TDC) and 40 ° after the lower charge exchange dead center (UT), in particular between 90 ° after the upper charge exchange dead center (LW-TDC) and 20 ° after the lower charge exchange dead center (TDC), takes place. Internal combustion engine ( 1 ) according to one of claims 1 to 4, characterized in that the air suction system ( 3 ) is designed such that a distributor tube length (L _V ) is dimensioned as a function of an equivalent distributor tube diameter (D _V ). Internal combustion engine ( 1 ) according to claim 5, characterized in that the configuration of the distributor tube length (L _V ) in dependence on an equivalent distributor tube diameter (D _V ) is such that the ratio of equivalent distributor tube diameter (D _V ) to distributor tube length (L _V ) 0.05 bis 0.14, or 0.06 to 0.13. Internal combustion engine ( 1 ) according to one of claims 1 to 6, characterized in that the design of the air suction system ( 3 ) takes place such that the suction tube length (L _S ) is shorter than 200 mm, or as 150 mm. Internal combustion engine ( 1 ) according to one of claims 1 to 7, characterized in that air suction system ( 3 ) two plenums ( 6 ), wherein the manifold ( 4 ) from a distributor module ( 4a ) and two distribution pipe sections ( 4b ) is formed, each distribution pipe section ( 4b ) between the distributor module ( 4a ) and one of the plenaries ( 6 ) is positioned. Internal combustion engine ( 1 ) according to one of claims 1 to 8, characterized in that the internal combustion engine ( 1 ) is designed as a spark-ignited internal combustion engine, in particular the boxer type, wherein the number of cylinders ( 2 ) is four, six or eight. Internal combustion engine ( 1 ) according to one of claims 1 to 9, characterized in that the distributor tube length (L _V ) is greater than a length L ₁ , which by a first Fromel: L ₁ = 200 - 4/3 · L _S + 1.7 · n _N ^-2.22 * (D _V ^-30 ) is determined, where L _{S of} the respective intake manifold, n _{N of} the rated speed of the internal combustion engine ( 1 ) and D _V corresponds to the equivalent manifold diameter. Internal combustion engine ( 1 ) according to one of claims 1 to 9, characterized in that the distributor tube length (L _V ) is smaller than a length (L ₂ ) represented by a second formula: L ₂ = 7.2 · 10 ⁶ / n _N -1, 5 · L _{S is} determined, where L _{S of} the respective length of the suction tube ( 7 ) and n _{N of} the rated speed of the internal combustion engine ( 1 ) corresponds. Internal combustion engine ( 1 ) according to one of claims 1 to 9, characterized in that the distributor tube length (L _V ) is greater than a length (L ₃ ) determined by a third Fromel: L ₃ = 34 · D _V - 650 · 4 / 3L _S. where L _S corresponds to the respective intake manifold length and D _V corresponds to the equivalent manifold diameter. Internal combustion engine ( 1 ) according to one of claims 1 to 12, characterized in that a second switchable distributor tube ( 12 ) is arranged. Internal combustion engine ( 1 ) according to one of claims 1 to 13, characterized in that in the second distributor tube ( 4 ) a switching flap ( 13 ) in front is seen, with the size of the equivalent manifold diameter (D _V ) is adjustable. Internal combustion engine ( 1 ) according to one of claims 1 to 14, characterized in that the internal combustion engine ( 1 ) has an exhaust gas turbocharger with an adjustable turbine geometry. Internal combustion engine ( 1 ) according to one of claims 1 to 15, characterized in that an additional increase of the boost pressure by the compressor ( 8th ), whereby the set boost pressure values are between 5% and 15% higher than a value which is between 0.9 bar and 1.5 bar. Internal combustion engine ( 1 ) according to one of claims 1 to 16, characterized in that the inside of the air suction ( 3 ) achievable expansion as a function of operating parameters, in particular the rotational speed (n _N ) of the internal combustion engine ( 1 ), is adjustable.