WO2006066739A1

WO2006066739A1 - Method for operating an internal combustion engine with supercharged charge air and internal combustion engine

Info

Publication number: WO2006066739A1
Application number: PCT/EP2005/013179
Authority: WO
Inventors: Ulrich-Dieter Standt; Wilfried Rhode; Uwe Scher; Axel Groenendijk
Original assignee: Volkswagen
Priority date: 2004-12-17
Filing date: 2005-12-09
Publication date: 2006-06-29
Also published as: DE102004061613A1

Abstract

The invention relates to a method for operating an internal combustion engine and to an internal combustion engine (24) comprising an exhaust-gas turbocharger (30) for charging the air and an additional supercharger (compressor (40)) for injecting additional supercharged air during a performance increase or acceleration phase of the internal combustion engine. The additional supercharging is controlled by means of a regulation device to a great extent at the same time as an increase in the fuel-injection quantity, in such a way that the gross air ratio of λ (Lambda) = 1.1 is met. The additional supercharger (compressor (40)) can be directly coupled mechanically to the internal combustion engine (24) by means of a magnetic coupling (46), if the driver demands an increase in performance or acceleration via the accelerator pedal.

Description

Method for operating an internal combustion engine with charge air charging and internal combustion engine

The invention relates to a method of operating an internal combustion engine according to the preamble of claim 1 and a Verbrennungskräftmaschine according to the preamble of claim 5. ^■

Modern internal combustion engines, especially diesel engines, are usually operated with a supercharger, which makes it possible to increase the power of an engine over a naturally aspirated engine with a comparable displacement. It is already known to connect superchargers directly mechanically to the morter. This arrangement has advantages, particularly in terms of the response, since the speed-dependent delivery performance of the supercharger is in direct relation to the speed of the internal combustion engine and thus to the required amount of combustion air because of the direct coupling of the supercharger with the internal combustion engine. However, superchargers which are directly powered by the internal combustion engine are less favorable in terms of fuel consumption than the known exhaust gas turbochargers in which the drive energy for the supercharger is taken from the exhaust gas. However, this advantage is offset by the known problem of the slower response time of turbocharged turbocharged engines ("turbolag"). The lack of air during the power increase phase can also lead to a pronounced smoke emission, i. lead to increased particulate emissions, because the particles are formed by motor-induced local air deficiency conditions during combustion.

A remedy offers the delay of fuel enrichment, but with a reduction in performance and thus, for example, with an extension of the. Acceleration phase is connected. The limitation of the fuel injection is therefore not a viable alternative to the charge air charge.

In order to compensate for the disadvantages of the economical and therefore predominantly used exhaust gas turbocharger, means are already known for blowing in additional charge air into the charge air system during the phase of increasing the power of the internal combustion engine. DE 39 06 312 C1 shows and describes an acceleration aid for a charged by means of exhaust, gas turbocharged internal combustion engine, in which the additional charge air is taken from a compressed air tank, which is supplied by a coupled with the internal combustion engine gβr compressor with compressed air. Such an arrangement is structurally very complicated because of the additional compressed air tank and the installation space to be kept free for this reason and therefore comes essentially hur for trucks in question, in which a compressed air tank is present as part of the brake system anyway.

DE 199 34 606 A1 already discloses a device and a method for increasing the power of an internal combustion engine charged by means of an exhaust gas turbocharger, in which an additional compressor is provided, which is driven by a special electric machine drivingly connected to the internal combustion engine. The additional compressor is arranged parallel to the compressor of Äbgasturboladers and connectable via a system of valves and lines with the charge air line for the internal combustion engine. In addition to its function as a starter motor and as an alternator, the electric machine also has the function, if required, of driving the additional compressor, which supplies the additional charge air. For this purpose, the electric machine is brought to an extremely high speed required for the operation of the additional compressor via complicated control electronics. Apart from the fact that the entire arrangement is complex and structurally complex, there is also in this arrangement due to the time for the start-up of the electric machine response delay, so that even in this arrangement to be reckoned with the increased particulate emissions described above in connection with the exhaust gas turbochargers is. ,.

The invention is therefore based on a method for operating an internal combustion engine with a Abgasturbόlader Ladeluftauflädung during normal operation and with an additional compressor or the like for blowing additional charge air during a phase of power increase or acceleration, as well as of an operating according to this method internal combustion engine, the The invention is, on the one hand, to improve the method described above in such a way that a power increase or acceleration without power limitation is possible to a value below the maximum possible power with simultaneous particle-poor combustion. Another object is to provide an internal combustion engine that operates according to the method described above and solves the underlying task. , These objects are achieved by a method according to claim 1 or by an internal combustion engine according to claim 5. In the claims according to these claims, favorable embodiments of the invention are described.

The inventive method provides that the additional charge air injection is controlled via a control device largely simultaneously with the increase of the fuel injection amount so that a gross air ratio of λ =: 1, 1 does not fall below, in other words λ is greater than or equal 1.1.

In normal driving, the air ratio is approximately at λ = 1, 9 - 2. If the driver requests, for example by pedaling the accelerator pedal performance or acceleration, then more fuel is injected, so that for the reasons described earlier without additional air injection, the air ratio would fall sharply. According to the invention, however, additional charge air is blown regulated at the same time with the increase of Kraftstoffeinspritzmeήge, in such a way that the air ratio does not fall below λ = 1.1 during the entire acceleration phase. In this way, without limiting the injection quantity, i. without a reduction, the engine performance by increasing the charge air mass causes an increase in the air ratio and thus a combustion with less particle formation.

According to a preferred embodiment of the method according to the invention, the additional charge air injection is controlled so that a gross air ratio in the range of, λ> 1, 2 is maintained;

In order to ensure the lowest possible response delay, it is provided according to a further embodiment of the invention that in the control device, the power requirement of the driver, such as the accelerator pedal position, is entered as a control variable. This ensures that the control device receives the important information for the control process with respect to the increased amount of fuel at the same time as the power requirement 'by the driver, so that they can respond to it without delay.

In a further embodiment of the invention, it is provided that the current λ-value is constantly measured and / or calculated and as a further controlled variable in the control device is entered. This makes it possible to regulate the additional charge air quantity so that the desired λ value is maintained.

Starting from an internal combustion engine with an exhaust gas turbocharger and with an additional charger for injecting additional charge air during an increase in power or acceleration of the internal combustion engine is provided according to the invention that the additional charger with the internal combustion engine is mechanically coupled directly. Due to the direct coupling of the supercharger with the internal combustion engine, the speed-dependent charging power always increases at the same time with a speed increase of the internal combustion engine, so that a delay-free injection of the additional charge air is ensured.

In a further embodiment of the invention, it is provided that the additional charger with the internal combustion engine is selectively coupled or decoupled from this. In this way, the loader can be completely decoupled during the operating phases in which no additional air injection is required, so that even an idle drive 'performance is eliminated.

The coupling of the additional supercharger with the internal combustion engine is carried out according to a further embodiment of the invention via a Mägnetkupplung. Magnetic couplings are very reliable, structurally simple and therefore cost-effective components.

In a preferred embodiment of the invention it is provided that the additional loader is arranged in series with the compressor of the exhaust gas turbocharger. It is possible to arrange the additional loader, for example, depending on the existing installation space in the flow direction of the charge air behind the compressor of the exhaust gas turbocharger; so that it further compresses the charge air precompressed by this compressor, or to arrange the loader upstream of the compressor in the flow direction, so that it supplies supercharged charge air to the compressor.

As additional loaders, for example, flow compressors or loader operating according to the displacement principle are considered, which are referred to below as compressors. The G-loaders known per se have proven to be particularly suitable. Several embodiments of the invention are illustrated in the drawings and described in more detail below. Show it:

Figure 1 is a block diagram of the basic arrangement of an engine associated with an exhaust gas turbocharger urtd ¹ additional supercharger (compressor), the additional supercharger is arranged in the flow direction of the charge air behind the exhaust gas turbocharger.

Figure 2 is a view similar to Figure 1, with the additional loader (compressor), however, is arranged in front of the exhaust gas turbocharger.

3 shows a schematic representation of the different functional elements of an internal combustion engine according to FIG. 1;

Fig. 4. in a schematic representation of the basic functional elements of an internal combustion engine according to FIG. 2.

1 shows a verbnηnungskraftmaschine 2, for example, a self-ignition or spark-ignition engine whose exhaust gases represented by the arrow 4 of the turbine 6 as a whole with. 8 designated exhaust gas turbocharger be supplied. After the exhaust gases have passed through the turbine 6, they are cleaned in a filter 10 and then released into the environment.

The compressor 12 of the exhaust gas turbocharger 8 sucks fresh air represented by an arrow 14 and compresses it to the charge pressure intended for normal driving operation. During normal driving operation, the compressed charge air indicated by the arrow 16 is passed around the compressor 18 and fed directly to the internal combustion engine 2.

In a request for an increase in power or acceleration input by the driver, the air compressed by the compressor 12 is supplied to and compressed by the compressor 18, so that the internal combustion engine 2 is supplied with a charge air amount corresponding to the increased fuel injection Measures that particle formation is largely prevented. , With the arrows 20 and 22, the possible ways of exhaust gas recirculation are designated. Accordingly, a part of the exhaust gases (arrow 4) can be discharged behind the internal combustion engine 2 and mixed with the compressed or recompressed charge air. Another possibility is to divert a portion of the exhaust gases behind the filter 10 and to mix the non-compressed charge air (arrow 14). ,

Fig. 2 shows an arrangement similar to Fig. 1, wherein like elements are provided with the same reference numerals. The arrangement according to FIG. 2 differs from that of FIG. 1 essentially only in that the compressor 18 'is arranged upstream of the compressor 12 of the exhaust gas turbocharger 8 in the direction of flow of the charge air indicated, for example, by the arrow 14. The uncompressed charge air (arrow 14) is guided around the compressor 18 'in normal operation and compressed in the compressor 12 of the exhaust gas turbocharger 8 to the intended for normal operation boost pressure. In the case of a request for an increase in power or acceleration, the uncompressed charge air (arrow 14) is precompressed in the compressor 18 ', subsequently compressed in the compressor 12 of the exhaust gas turbocharger 8 and then supplied to the internal combustion engine 2.

The arrows 20 and 22 again indicate possible ways of exhaust gas recirculation, as already explained in connection with FIG.

FIG. 3 shows a more detailed schematic representation of an internal combustion engine arrangement, for example according to FIG. 1. The exhaust gases of the internal combustion engine 24 are collected in an exhaust manifold 26 and fed to the turbine 28 of an exhaust gas turbocharger, designated as a whole by 30, which drives a compressor 32. The compressor 32 sucks in fresh air via an air filter 34 and compresses it to a charge pressure intended for normal driving operation. The compressed charge air is cooled in a Lädeluftkühjer 36 arranged, for example behind the compressor 32 and fed in normal driving over a Bypassveπtil 38 of the internal combustion engine 24. -,

For example, when the operator inputs a request for an increase in power via the accelerator pedal, the bypass valve 38 is closed and the precompressed air is passed over the compressor 40 and subsequently recompressed therein, so that the internal combustion engine 24 receives the increased fuel injection correspond The larger amount of charge air is supplied in such a way that particle formation is prevented.

The compressor 40 can be coupled, for example via a belt drive 42, to the combustion engine 24. For this purpose, the compressor-side pulley 44 is associated with a controllable by means of a control device magnetic coupling 46, by means of which the compressor 40 is selectively coupled to the internal combustion engine 24 and decoupled from this.

48 designates a charge air cooler, which may be provided as an alternative or in addition to the intercooler 36.

Fig. 4 shows an arrangement similar to Fig. 3; the same elements are each provided with the same reference numerals.

FIG. 4 again differs from FIG. 3 only in that the compressor 40 'is arranged in front of the compressor 32 of the exhaust-gas turbocharger 30 in the flow direction of the charge. -,

During normal driving operation, the fresh air sucked in via the air filter 34 is supplied to the compressor 32 via the bypass valve 38. The compressed air in the compressor 32 is supplied via the intercooler 48 of the internal combustion engine 24.

In the case of a request for an increase in power or acceleration, the bypass valve 38 is closed, so that the fresh air in the compressor 40 'pre-compressed and then fed to the compressor 32, in which it is recompressed, so that the internal combustion engine 24 one of the increased fuel injection corresponding larger charge air quantity supplied and particle formation is prevented.

The compressor 40 'is as in the example of FIG. 3 via a magnetic coupling 46 selectively coupled to the internal combustion engine 24 and can be uncoupled from this.

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LIST OF REFERENCE NUMBERS

Internal combustion engine

Arrow - exhaust gases

Turbine. ,

Turbocharger 0 Filter 2 Compressor 4 Arrow Fresh air 6 Arrow - Charge air

18 'Compressor 0 Arrow - Exhaust gas recirculation 2 Arrow - Exhaust gas recirculation 4 Internal combustion engine 6 Exhaust manifold 8 Turbine 0 Exhaust gas turbocharger 2 Compressor 4 Air filter 6 Charge air cooler 8 Bypass valve 0, 40' Compressor 2 Belt drive 4 Belt pulley 6 Magnetic clutch 8 Charge air cooler

Claims

PATENT CLAIMS E

1. A method for operating an internal combustion engine with an exhaust gas turbocharger for supercharging and with an additional charger for injecting additional charge air during a phase of increasing the power or acceleration of the internal combustion engine, characterized in that the additional charge air injection by means of a control device largely simultaneously with an increase in Kraftstόff Injection amount is controlled so that a gross air ratio of λ (lambda) = 1, 1 is not exceeded.

2. The method according to claim 1, characterized in that the additional charge air injection is controlled so that a gross air ratio in the range of λ> 1, 2 is maintained.

3. The method according to claim 1 or 2, characterized in that in the control device, the requirement of a Leistungsuηgserhöhung or acceleration by the driver (accelerator pedal position) is entered as a control variable. , ; , , _,

4. The method according to any one of claims 1 to 3, characterized in that the current lambda value is constantly measured and / or calculated and entered as a controlled variable in the control device.

5. Internal combustion engine with an exhaust gas turbocharger and with an additional charger for blowing additional charge air during a phase of power increase or acceleration of the internal combustion engine, characterized in that the additional charger (compressor 40, 40 ') with the internal combustion engine (24) directly coupled mechanically is.

6. Internal combustion engine according to claim 5, characterized in that the additional loader (compressor 40, 40 ') with the internal combustion engine (24) is selectively coupled or decoupled from this.

7. Internal combustion engine according to claim 5, characterized in that the additional loader (compressor 40, 40 ') with the internal combustion engine (24) via a magnetic coupling (46) can be coupled.

8. Internal combustion engine according to one of claims 5 to 7, characterized in that the additional loader (compressor 40, 40 ') in series with the compressor (32) of the exhaust gas turbocharger (30) is arranged.

9. internal combustion engine according to claim 8, characterized in that the additional charger (compressor 40) is arranged in the flow direction of the charge air behind the compressor (32).

10. Internal combustion engine according to claim 8, characterized in that the additional loader (compressor 40 ') in the flow direction of the charge air upstream of the compressor (32) is arranged.

11. Internal combustion engine according to one of claims 5 to 10, characterized in that the additional loader is a compressor (40, 40 ').

12. Internal combustion engine according to claim 11, characterized in that the additional loader (compressor 40, 40 ') is a G-loader. ,.