Turbocharged engine system and method for controlling air intake and emissions therefor - Patents.com

Abstract

A turbocharged engine system (1) is described. The turbocharged engine system comprises a combustion engine (10) having at least one cylinder (11), at least one intake valve (12) configured to supply intake air to the at least one cylinder (11), and at least one exhaust valve (13) configured to exhaust exhaust from the at least one cylinder (11). The at least one intake valve (12) is configured to provide a constant Miller timing or a constant Atkinson timing. Additionally, the turbocharged engine system includes at least one turbocharger (14) having a turbine (15) and a compressor (16) for pressurizing the intake air, at least one power converter (17) coupled to at least one of the compressor (16) and the turbine (15), and a controller (18) configured to control the at least one power converter (17) to supply power to or extract power from at least one of the compressor (16) and the turbine (15) to achieve a target value of at least one operating parameter of the combustion engine (10).

Description

[Technical Field]

[0001] FIELD OF THE DISCLOSURE Embodiments of the present disclosure relate to turbocharged engine systems. Further embodiments of the present disclosure relate to methods of air charge and emission control for turbocharged engine systems. [Background technology]

[0002] One of the most important pollutants of internal combustion engines is NO x (oxides of nitrogen). This pollutant is formed at high temperatures and in excess of O2, which is generally associated with good engine efficiency. Therefore, NO x Reducing NO generally results in a decrease in efficiency. x The lower the emissions, the lower the efficiency. NO after engine exit, known as conventional exhaust aftertreatment (EAT) x Countermeasures to reduce this are complex, bulky and expensive.

[0003] For example, at the engine outlet and before the optional EAT system, raw NO x Several solutions already exist to reduce emissions. A typical solution is exhaust gas recirculation (EGR), which recirculates part of the exhaust gases back into the intake. The aim is to introduce inert gas (CO2) into the cylinder together with the air and, to some extent, to reduce the highest cycle temperature during combustion (slow combustion and heat capacity effects). This technology can cause ageing problems and significantly reduce engine efficiency. For lean-burn gas engines, EGR reduces the amount of air at a given load and therefore also the excess O2, resulting in possible NO x Emissions can be reduced.

[0004] Another solution is to inject water directly into the intake or cylinder (similar concept to EGR, but using H2O instead of CO2). This technique requires additional tanks, pumps, and circuits, and often comes with a moderate [NOx; efficiency] trade-off.

[0005] Yet another solution is to combine Miller or Atkinson valve timing with a sophisticated supercharger or turbocharger system. In this case, the idea is to artificially shorten the intake stroke by closing the intake valve while the piston is still inhaling (Miller), or the compression stroke by closing the intake valve while the piston has already started to move upward (Atkinson), while simultaneously compensating for the lack of air volume by further increasing boost pressure. Thus, the higher overall compression ratio established by aftercooled supercharging or turbocharging (rather than piston-driven compression) results in a lower temperature at the end of the cylinder compression stroke, lowering the maximum combustion temperature and, consequently, NO x This leads to a reduction in production.

[0006] To increase efficiency while reducing NOx emissions, some internal combustion engines are now equipped with systems that allow them to operate with Miller timing. In such systems, the intake valve is closed much earlier during the intake stroke, significantly reducing cylinder air intake (volumetric efficiency). To maintain the required air mass flow rate for the engine, turbochargers are employed to compensate for the lack of intake by allowing a greater pressure ratio (greater intake receiver density). In many cases, this requires the addition of another compression stage, leading to a switch from a single-stage turbocharger to a two-stage turbocharger configuration.

[0007] However, the turbocharging system's compensation for this engine intake deficiency is only effective if there is sufficient energy in the exhaust gases at the turbocharger turbine inlet, which is almost always not the case at low engine speeds and / or loads. In other words, maintaining Miller timing at low engine speeds and / or loads is simply impossible because the turbocharger system cannot compensate for the lack of volumetric efficiency as it can at full engine power. Maintaining Miller timing at low engine speeds can also be problematic during engine start-up. The exact same difficulties can be encountered with constant Atkinson timing.

[0008] To solve this problem, the current state of the art teaches the use of a variable intake valve train that is configured to switch from Miller timing at high speeds and / or loads to non-Miller timing at low speeds and / or loads. However, variable intake valve train systems have the disadvantage of being fairly complex and expensive, as are Atkinson timing systems. Summary of the Invention [Problem to be solved by the invention]

[0009] In view of the above, therefore, there is a need for an improved turbocharged engine system and method of providing air charge and emissions control for an improved turbocharged engine system that at least partially overcomes some of the problems of the prior art. [Means for solving the problem]

[0010] In view of the above, there are provided turbocharged engine systems and methods of air charge and emission control for turbocharged engine systems according to the independent claims. Furthermore, methods of controlling the operation and use of turbocharger assemblies according to the embodiments described herein are described. Further aspects, advantages, and features are apparent from the dependent claims, the description, and the accompanying drawings.

[0011] According to one aspect of the present disclosure, a turbocharged engine system is provided. The turbocharged engine system includes a combustion engine having at least one cylinder. The turbocharged engine system further includes at least one intake valve configured to supply intake air or an air-fuel mixture to the at least one cylinder and at least one exhaust valve configured to exhaust exhaust from the at least one cylinder. The at least one intake valve is configured to provide a constant cyclic valve timing between an open state and a closed state of the at least one intake valve. The constant cyclic valve timing is Miller timing or Atkinson timing. Additionally, the turbocharged engine system includes at least one turbocharger having a turbine and a compressor for compressing the intake air or the air-fuel mixture. The turbocharged engine system further includes at least one power converter coupled to at least one of the compressor and the turbine. The turbocharged engine system further includes a controller configured to control the at least one power converter to supply power to or extract power from at least one of the compressor and the turbine to achieve a target value of at least one operating parameter of the combustion engine. res,T and sized such that the power generated by the turbine provides the power required by at least the compressor to reach the target value of the at least one operating parameter without using the at least one power converter as a motor during non-accelerated operation of the combustion engine.

[0012] According to a further aspect of the present disclosure, there is provided a method for controlling air intake and emissions in a turbocharged engine system. The turbocharged engine system includes a combustion engine having at least one cylinder, at least one intake valve configured to supply intake air or an air-fuel mixture to the at least one cylinder, at least one exhaust valve configured to exhaust exhaust from the at least one cylinder, at least one turbocharger having a turbine and a compressor for compressing the intake air or the air-fuel mixture, at least one power converter coupled to at least one of the compressor and the turbine, and a controller configured to control the power converter. The turbine has an effective cross-sectional area S res,T The method includes a controller controlling the at least one power converter to power at least one of the compressor and the turbine only during an acceleration mode of the combustion engine. Alternatively or additionally, the method includes a controller controlling the at least one power converter to extract power from at least one of the compressor and the turbine only during a non-acceleration mode to achieve the target value of the at least one operating parameter of the combustion engine.

[0013] Thus, an improved turbocharged engine system and method for controlling the air intake and emissions of an improved turbocharged engine system are provided compared to the prior art. In particular, the embodiments described herein reduce system complexity, reduce costs, and provide NO xThis is beneficial for reducing emissions and improving efficiency. Additionally, the turbocharged engine system concepts of the present disclosure beneficially provide the potential for easy retrofitting of existing engine systems by providing constant Miller timing or Atkinson timing, as described herein, in combination with an easily add-on controller (e.g., during an upgrade procedure) for controlling a power converter coupled to the turbocharger. Furthermore, a power converter coupled to the turbocharger can also improve the performance of the turbocharged engine system, such as acceleration and load pickup capability.

[0014] So that the foregoing features of the present disclosure may be understood in detail, a more particular description of the disclosure briefly summarized above may be had by reference to the following embodiments. The accompanying drawings relate to embodiments of the present disclosure and are described below. [Brief explanation of the drawings]

[0015] [Figure 1] 1 shows a schematic diagram of a turbocharged engine system according to embodiments described herein. [Figure 2] FIG. 1 shows a schematic diagram of a turbocharged engine system according to further embodiments described herein. [Figure 3] FIG. 1 is a block diagram illustrating an embodiment of a method for air charge and emissions control of a turbocharged engine system according to embodiments described herein. [Figure 4] FIG. 1 is a block diagram illustrating an embodiment of a method for air charge and emissions control of a turbocharged engine system according to embodiments described herein. [Figure 5] FIG. 1 is a block diagram illustrating an embodiment of a method for air charge and emissions control of a turbocharged engine system according to embodiments described herein. [Figure 6] FIG. 1 is a block diagram illustrating an embodiment of a method for air charge and emissions control of a turbocharged engine system according to embodiments described herein. DETAILED DESCRIPTION OF THE INVENTION

[0016] Reference will now be made in detail to various embodiments, one or more examples of which are illustrated in each figure. Each example is provided by way of illustration and not by way of limitation. For example, features illustrated or described as part of one embodiment can be used on or in combination with any other embodiment to yield yet a further embodiment. The present disclosure is intended to include all such modifications and variations.

[0017] In the following description of the drawings, the same reference numbers refer to the same or similar components. Generally, only the differences with respect to individual embodiments are described. Unless otherwise specified, the description of a part or aspect in one embodiment may also apply to the corresponding part or aspect in another embodiment.

[0018] A turbocharged engine system 1 according to the present disclosure is described, by way of example, with reference to FIG. 1 . According to an embodiment that may be combined with other embodiments described herein, the turbocharged engine system 1 includes a combustion engine 10 having at least one cylinder 11, at least one intake valve 12 configured to supply intake air or an air-fuel mixture (i.e., intake gas / intake gas mixture) to the at least one cylinder 11, and at least one exhaust valve 13 configured to exhaust exhaust from the at least one cylinder 11. It should be understood that the intake gas / intake gas mixture may include at least one of air, fuel, recirculated exhaust gas, and water. The at least one intake valve 12 is configured to provide a constant periodic valve timing between an open state and a closed state of the at least one intake valve. In particular, the phrase "at least one intake valve" can be understood as "at least one intake valve system." The constant periodic valve timing may be Miller timing or Atkinson timing. The turbocharged engine system 1 further includes at least one turbocharger 14 having a turbine 15 and a compressor 16 for compressing intake air or an air-fuel mixture. Generally, the turbine 15 is configured to recover enthalpy from the exhaust gases. The turbocharged engine system 1 further includes at least one power converter 17 coupled to at least one of the compressor 16 and the turbine 15. The turbocharged engine system 1 further includes a controller 18 configured to control the at least one power converter 17 to supply power to or extract electrical power from at least one of the compressor 16 and the turbine 15 to achieve a target value of at least one operating parameter of the combustion engine 10. The turbine 15 has an effective cross-sectional area S res,T which is sized so that the power generated by the turbine 15 provides the power required by at least the compressor to reach the target value of the at least one operating parameter without using the at least one power converter 17 as a motor during non-accelerated operation of the combustion engine 10.

[0019] Thus, an improved turbocharged engine system is provided compared to the prior art. In particular, the turbocharged engine system described herein provides a NOx reduction while reducing system complexity resulting in overall cost savings. x This is beneficial for reducing emissions and improving efficiency. Additionally, the turbocharged engine system concepts described herein beneficially provide the ability to easily retrofit existing engine systems, i.e., by providing constant Miller timing or Atkinson timing in combination with a controller for controlling a power converter coupled to a turbocharger as described herein. Furthermore, embodiments of the turbocharged engine systems described herein beneficially provide improved performance, particularly improved acceleration performance and improved load pickup capability.

[0020] Before describing various further embodiments of the present disclosure in more detail, some aspects regarding some of the terms used herein will be explained.

[0021] In the present disclosure, "at least one cylinder" can be understood to mean one or more cylinders. For example, the combustion engine described herein may have a number N C It can contain N cylinders C is 1≦N C It can be selected from the range of ≦30.

[0022] In the present disclosure, "at least one intake valve" can be understood to mean that one or more intake valves can be provided. For example, the at least one cylinder described herein may have a number N IV The intake valve may include N IV is 1≦N IV It can be selected from the range of ≦4.

[0023] In the present disclosure, "at least one exhaust valve" can be understood to mean that one or more exhaust valves can be provided. For example, the at least one cylinder described herein may have a number N OV The exhaust valve may include OV is 1≦N OV It can be selected from the range of ≦4.

[0024] In this disclosure, "Miller timing" can be understood as timing according to the Miller cycle. In a Miller cycle, the intake valve closes earlier in the cycle than in a conventional diesel engine or a Baux de Rochas / Otto cycle engine. In effect, the intake stroke is shortened, reducing volumetric efficiency and resulting in a lower mass (charge) of air or fuel-air mixture trapped in the cylinder for a given intake-canister air density. This loss of charge generally results in a loss of power. However, in a Miller cycle, this can be compensated for by the use of a turbocharger. Generally, the turbocharger must be positive displacement due to its ability to generate sufficient boost already at relatively low engine speeds and / or loads. Otherwise, power output at low engine speeds and / or loads will have a reduced capacity for load pickup. In a Miller cycle engine, at the beginning of the compression stroke when the piston is at its lowest point, the cylinder pressure is lower than the intake-canister pressure. This means that it takes a sufficient time for the cylinder pressure to reach the same level as the intake-canister pressure after the piston has moved upward from its lowest point. Therefore, in a Miller cycle engine, the piston actually compresses the air or fuel-air mixture only for the remainder of the compression stroke after the intake valve has closed. Miller valve timing can be defined as when at least one of the intake valves is already closed before the piston reaches its lowest position, 20 degrees crank angle, at the end of the intake stroke. A closed valve can be defined as "the point when the valve under consideration is at or below 10% of its maximum lift." For example, if an intake valve has a maximum lift of 26 mm, the valve is considered closed when the lift is below 2.6 mm.

[0025] In this disclosure, "Atkinson timing" can be understood as timing according to the Atkinson cycle. In the Atkinson cycle, the intake valves remain open longer than normal, allowing the reverse flow of intake air or fuel-air mixture toward the intake manifold. The effective compression ratio decreases (at this point, the intake air or fuel-air mixture is freely expelled from the cylinder rather than compressed), but the expansion ratio remains unchanged (i.e., the compression ratio is less than the expansion ratio). Atkinson valve timing can be defined as when at least one of the intake valves is open at the bottom of the piston, after the end of the intake stroke, and 20 crank angles. An open valve can be defined as "the point when the valve under consideration is at or above 10% of its maximum lift." For example, if the maximum lift of an intake valve is 41 mm, the valve is considered open when the lift is 4.1 mm or greater.

[0026] It should be understood that originally the goal of the Miller and Atkinson cycles was to make the expansion stroke longer than the compression stroke (or equivalent), resulting in improved cycle efficiency. Implicitly and as already explained, these two cycles ultimately provide a better compromise in supercharged or turbocharged engines, particularly through a reduction in maximum combustion temperature. x , efficiency].

[0027] In the present disclosure, "at least one turbocharger" can be understood to mean that one or more turbochargers can be provided. According to one embodiment, one turbocharger can provide a single-stage air intake system, two turbochargers can provide a two-stage air intake system, and three turbochargers can provide a three-stage air intake system. Thus, a turbocharged engine system can have a number N TC It can be equipped with a turbocharger of N TC is 1≦N TC It may be selected from the range of ≦4. When two or more turbochargers are provided, the two or more turbochargers may be arranged in parallel.

[0028] In this disclosure, the phrase "at least one power converter coupled to at least one of the compressor and the turbine" may be understood to mean that one or more power converters may be provided that may be coupled to the compressor and / or the turbine. For example, the at least one power converter may be coupled to a shaft connecting the compressor and the turbine. Thus, the at least one power converter may be disposed between the compressor and the turbine of a turbocharger. Such a configuration may be referred to as an e-turbo. Alternatively, the at least one power converter may be coupled only to the compressor, for example, via a shaft, and such a configuration may be referred to as an e-compressor.

[0029] According to another embodiment, the at least one power converter may be coupled only to the turbine, for example via a shaft, which may also be referred to as an e-turbine. Typically, the at least one power converter is configured to convert electrical power into mechanical power or vice versa. In other words, the at least one power converter may be understood as an electrical device configured to recover energy by converting mechanical power into electrical power, in particular by electrically braking the turbine, when the turbine power is greater than the required compressor power, or configured to provide mechanical power from or to, for example, a turbocharger, in particular from or to a compressor / turbine, when the compressor requires more power than the turbine can provide.

[0030] In the present disclosure, the expression "controller configured to control at least one power converter" may be understood as an electronic device that is able to control at least one power converter, for example by means of a control signal.

[0031] In the present disclosure, "at least one operating parameter of the combustion engine" may be understood as any parameter of the combustion engine during operation that makes it possible to characterize the operating state of the combustion engine.

[0032] According to an embodiment, which can be combined with other embodiments described herein, the effective cross-sectional area S res,T is S res =(S Rt ×S St ) / (S Rt 2 +S St 2 ) 1 / 2 where S St is cm 2 The throat area of ​​the turbine stator in cm 2 is the throat area of ​​the nozzle ring of the turbine in units of S Rt is cm 2 The rotor throat area of ​​the unit turbine. It should be understood that the stator throat area is the smallest cross-sectional area of ​​the stator. The rotor throat area is the smallest cross-sectional area of ​​the rotor.

[0033] According to an embodiment, which can be combined with other embodiments described herein, the power from the turbine to be or to be supplied to the compressor is determined by the following formula:

number

number

[0034] According to an embodiment, which may be combined with other embodiments described herein, the controller 18 is configured to compare an actual value of the at least one operating parameter with a target value of the at least one operating parameter. Furthermore, the controller 18 is configured to control the at least one power converter 17 when there is a deviation between the actual value and the target value. For example, the actual value of the at least one operating parameter may be a measured value of the at least one operating parameter. According to another example, the actual value may be a calculated value from the measured value of the at least one operating parameter.

[0035] 2, according to an embodiment that may be combined with other embodiments described herein, the turbocharged engine system 1 includes at least one sensor 19 for measuring at least one operating parameter. Typically, the at least one operating parameter is an air mass flow rate Q in , air-fuel ratio λ, intake pressure p in , in particular the intake pressure or intake-fuel mixture pressure, the exhaust temperature T ex , and NO x Emission rate Q out It should be understood that one or more sensors configured to measure at least one operating parameter may be provided. For example, the at least one sensor 19 may be a flow meter, a lambda sensor, a pressure sensor, a temperature sensor, and / or a NO sensor. x A sensor may be included.

[0036] According to embodiments that may be combined with other embodiments described herein, at least one power converter 17 is configured for use as a motor and / or a generator. As exemplarily shown in FIG. 2 , according to embodiments that may be combined with other embodiments described herein, power converter 17 may include rotor 171 and stator 172. Typically, rotor 171 is coupled to shaft 141 that connects compressor 16 and turbine 15.

[0037] 3 to 6, an embodiment of a method 20 for controlling air intake and emissions of a turbocharged engine system 1 according to the present disclosure is described. The turbocharged engine system 1 includes a combustion engine 10 having at least one cylinder 11, at least one intake valve 12 configured to supply intake air or a fuel-air mixture to the at least one cylinder 11, and at least one exhaust valve 13 configured to discharge exhaust from the at least one cylinder 11. The turbocharged engine system 1 further includes at least one turbocharger 14 having a turbine 15 and a compressor 16 for compressing the intake air or the fuel-air mixture. In addition, the turbocharged engine system 1 includes at least one power converter 17 coupled to at least one of the compressor 16 and the turbine 15. The turbocharged engine system 1 further includes a controller 18 configured to control the power converter 17. The turbine 15 has an effective cross-sectional area S res,T , which is sized so that the power generated by the turbine 15 provides the power required by at least the compressor to reach the target value of at least one operating parameter without using the at least one power converter 17 as a motor during non-accelerated operation of the combustion engine 10. According to an embodiment, which can be combined with other embodiments described herein, the effective cross section S res,Tis sufficiently small so that the supply of electrical power is not required at low loads to reach the target value of at least one operating parameter, thereby allowing the engine to operate in the event of an electrical failure of at least one power converter (recovery mode).

[0038] According to an embodiment that may be combined with other embodiments described herein, a method 20 includes providing a constant periodic valve timing between an open state and a closed state of at least one intake valve (represented by block 21 in FIGS. 3-6 ). The constant periodic valve timing is Miller timing or Atkins timing. Furthermore, the method includes controlling at least one power converter 17 (represented by block 22 in FIGS. 3-6 ) by the controller 18 to supply power to at least one of the compressor 16 and the turbine 15 (represented by block 23 in FIGS. 3-6 ) only during an acceleration mode of the combustion engine 10. Additionally or alternatively, the method includes controlling at least one power converter 17 (represented by block 22 in FIGS. 3-6 ) by the controller 18 to extract power from at least one of the compressor 16 and the turbine 15 (represented by block 24 in FIGS. 3-6 ) only during a non-acceleration mode to achieve a target value of at least one operating parameter of the combustion engine 10. The at least one operating parameter may be a mass air flow rate (Q ). in , air-fuel ratio λ, intake pressure p in , in particular the intake pressure or intake-fuel mixture pressure, the exhaust temperature T ex , and NO x Emission rate Q out Typically, powering at least one of the compressor 16 and the turbine 15 (represented by block 23 in FIGS. 3-6 ) involves converting electrical power to mechanical power. Thus, extracting power from at least one of the compressor 16 and the turbine 15 (represented by block 24 in FIGS. 3-6 ) typically involves converting mechanical power to electrical power.

[0039] In this disclosure, acceleration mode can be understood as a mode in which engine power output changes at a constant or variable engine speed. In other words, acceleration mode is a mode in which engine power output fluctuations occur in a predetermined time slot. For example, for a constant engine speed of 1500 rpm, power output increases by 80-100% in 5 seconds. Another example of acceleration mode is that for a variable speed engine, power output increases by 20-40% in 1 minute.

[0040] In this disclosure, non-acceleration mode can be understood as engine load and speed being constant, i.e., engine load and speed not varying during a given time slot. For example, if the engine speed is 1000 rpm, the engine load is constant at 85% for 30 seconds. Another example of non-acceleration mode is, for a variable speed engine, engine load being constant at 40% and speed being constant at 40% for 4 hours.

[0041] 4-6 by way of example, according to an embodiment that may be combined with other embodiments described herein, method 20 further includes comparing an actual value of at least one operating parameter with a target value of the at least one operating parameter (represented in FIGS. 4-6 by block 25), and controlling at least one power converter 17 by controller 18 if there is a deviation between the actual value and the target value (represented in FIGS. 4-6 by block 22). In particular, at least one power converter 17 may be controlled by controller 18 to minimize the deviation between the actual value and the target value in order to achieve the target value of the at least one operating parameter of the combustion engine.

[0042] According to embodiments that may be combined with other embodiments described herein, the actual value of the at least one operating parameter may be a measured value of the at least one operating parameter. Thus, and referring by way of example only to Figures 5 and 6, method 20 may include measuring the actual value of the at least one operating parameter with sensor 19 (represented by block 26 in Figures 5 and 6).

[0043] According to another embodiment, the actual value may be a calculated value calculated from measurements of the at least one operating parameter. Thus, and illustratively referring to Figure 6, method 20 may include calculating (represented in Figure 6 by block 27) an actual value of the at least one operating parameter from measurements of the at least one operating parameter.

[0044] Therefore, in view of the embodiments described herein, a turbocharged engine system and a method for controlling the air intake and emissions of a turbocharged engine system may be provided that, among other things, improves system efficiency and NOx reduction. x It is understood that this provides an improvement over the prior art in terms of emission reduction, while at the same time allowing for a reduction in the complexity of the system and therefore good cost efficiency. Furthermore, according to an embodiment which can be combined with other embodiments described herein, the effective cross section S res,T Note that is small enough so that the supply of electrical power is not required at low loads to reach the target value of at least one operating parameter, which allows the engine to operate in the event of an electrical failure of at least one power converter (recovery mode).

[0045] While the above is directed to exemplary embodiments, other and further embodiments may be devised without departing from the basic scope thereof, which scope is determined by the claims that follow. [Explanation of symbols]

[0046] 1. Turbocharged engine system 10 Combustion Engine 11 cylinders 12 Intake valve 13 Exhaust valve 14 Turbocharger 141 Shaft 15 Turbine 16 Compressor 17 Power Converter 171 Rotor 172 Stator 18 Control Device 19 Sensors 20. Method for controlling air intake and emissions from a combustion engine 21, 22, 23, 24, 25, 26, 27 Block diagram for explaining an embodiment of the method for controlling the air intake and emissions of a combustion engine of the present invention P in Intake pressure Q in Air Mass Flow Rate Q out NOx emission rate λ Air-fuel ratio T ex Exhaust temperature

Claims

1. A turbocharged engine system (1), comprising: a combustion engine (10) having at least one cylinder (11); at least one intake valve (12) configured to supply intake air or an air-fuel mixture to the at least one cylinder (11), the at least one intake valve (12) configured to provide a constant cyclic valve timing between an open state and a closed state of the at least one intake valve, the constant cyclic valve timing being Miller timing or Atkinson timing; at least one exhaust valve (13) configured to discharge exhaust from said at least one cylinder (11); at least one turbocharger (14) having a turbine (15) and a compressor (16) for compressing the intake air or air-fuel mixture; at least one power converter (17) coupled to at least one of the compressor (16) and the turbine (15); a control device (18) configured to control the at least one power converter (17) to supply power to or extract power from at least one of the compressor (16) and the turbine (15) to achieve a target NO x emission rate Q out of the combustion engine (10); Equipped with The turbine (15) has an effective cross-sectional area S res,T and the effective cross-sectional area S res,T The turbocharged engine system (1), wherein the power generated by the turbine (15) is sized to supply at least the power required by the compressor to reach the target value of NO x emission rate Q out without using the at least one power converter (17) as a motor during non-accelerated operation of the combustion engine (10).

2. The turbocharged engine system (1) of claim 1, wherein the control device (18) is configured to compare an actual value of the NO x emission rate Q out with a target value of the NO x emission rate Q out, and the control device (18) controls the at least one power converter (17) when there is a deviation between the actual value and the target value.

3. A turbocharged engine system (1) as described in claim 2, wherein the actual value of the NO x emission rate Q out is a measured value of the NO x emission rate Q out, or the actual value is a calculated value from the measured value of the NO x emission rate Q out.

4. A turbocharged engine system (1) according to any one of claims 1 to 3, further comprising at least one sensor (19) for measuring the NO x emission rate Q out .

5. 4. The turbocharged engine system (1) of claim 1, wherein the at least one power converter (17) is configured to be used as at least one of a motor during an acceleration mode of the combustion engine (10) and as a generator only during a non-acceleration mode.

6. The effective cross-sectional area S res,T is S res = (S Rt ×S St ) / (S Rt 2 +S St 2 ) 1 / 2 where S St is cm 2 is the throat area of ​​the stator of the turbine in units of S Rt is cm 2 4. The turbocharged engine system (1) according to any one of claims 1 to 3, wherein the rotor throat area of ​​the turbine is a unit.

7. A method (20) for controlling intake and emissions of a turbocharged engine system (1), the turbocharged engine system (1) comprising: a combustion engine (10) having at least one cylinder (11); at least one intake valve (12) configured to supply intake air or an air-fuel mixture to said at least one cylinder (11); at least one exhaust valve (13) configured to discharge exhaust from said at least one cylinder (11); at least one turbocharger (14) having a turbine (15) and a compressor (16) for compressing the intake air or air-fuel mixture; at least one power converter (17) coupled to at least one of the compressor (16) and the turbine (15); a control device (18) configured to control the power converter (17); Equipped with The turbine (15) has an effective cross-sectional area S res,T and the effective cross-sectional area S res,T is sized such that the power generated by the turbine (15) provides at least the power required by the compressor to reach a target value of NO x emission rate Q out without using the at least one power converter (17) as a motor during non-accelerating operation of the combustion engine (10); The method comprises: providing a constant periodic valve timing between an open state and a closed state of the at least one intake valve, the constant periodic valve timing being Miller timing or Atkinson timing; controlling (22) the at least one power converter (17) by the control device (18) to supply (23) power to at least one of the compressor (16) and the turbine (15) only during acceleration modes of the combustion engine (10) and / or to extract (24) power from at least one of the compressor (16) and the turbine (15) only during non-acceleration modes to achieve the target value of the NO x emission rate Q out of the combustion engine (10); A method (20).

8. A method (20) as described in claim 7, further comprising a step (22) of comparing (25) the actual value of the NO x emission rate Q out with a target value of the NO x emission rate Q out, and controlling the at least one power converter (17) by the control device (18) if there is a deviation between the actual value and the target value.

9. The method (20) of claim 8, wherein the actual value of the NO x emission rate Q out is a measured value of the NO x emission rate Q out, or the actual value is a calculated value from a measured value of the NO x emission rate Q out.

10. The method (20) of claim 8, further comprising the step (26) of measuring the actual value of the NO x emission rate Q out by means of a sensor (19).

11. The method (20) of any one of claims 8 to 10, further comprising the step (27) of calculating the actual value of the NO x emission rate Q out from measured values ​​of the NO x emission rate Q out .

12. 11. The method (20) of any one of claims 8 to 10, wherein powering (23) at least one of the compressor (16) and the turbine (15) comprises converting electrical power to mechanical power.

13. 11. The method (20) of any one of claims 8 to 10, wherein extracting (24) power from at least one of the compressor (16) and the turbine (15) comprises converting mechanical power to electrical power.

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