Engine assembly for an internal combustion engine of a motor vehicle

Abstract

Engine assembly (10) for an internal combustion engine of a motor vehicle, comprising at least one exhaust gas turbocharger (18) with a mechanically driven turbine (20) arranged in the exhaust branch (14) of the internal combustion engine, and a compressor (12) mechanically driven by the turbine (20) which is in fluid communication with an intake tract (26) of the internal combustion engine via a first line (28) in order to supply charged air to the intake tract (26) and to increase a pressure in the intake tract (26) of the internal combustion engine, and at least one electrically driven compressor (16) which is in fluid communication with an intake tract (26) of the internal combustion engine via a second line (30) in order to supply charged air to the intake tract (26) and to increase a pressure in the intake tract (26) of the internal combustion engine, wherein the first line (28) and the second line (30) open into one another at a junction point (32) and, starting from the junction point (32), a common line (34) runs to the intake tract (26), and wherein at least one valve element (36) is arranged between the mechanically driven compressor (12) and the node (32), which valve element is designed to either open or close a flow path from the mechanically driven compressor (12) to the intake tract (26), characterized in that the at least one valve element (36) is designed to be active.

Description

[0001] The invention relates to an engine assembly for an internal combustion engine of a motor vehicle.

[0002] To increase the performance and efficiency of internal combustion engines, it is common practice to increase the pressure in the intake system of an internal combustion engine, thereby increasing the amount of outside air drawn into a cylinder. For this purpose, a mechanically driven compressor is usually provided, which utilizes residual energy from the engine exhaust to increase the pressure in the intake system. Such mechanically driven compressors are, for example, components of exhaust gas turbochargers.

[0003] Since the mechanically driven compressor does not receive enough drive energy from the exhaust system in the low speed range to increase the pressure in the intake system, an electrically driven compressor can be provided in parallel and switched on when required.

[0004] The problem, however, is that the electrically driven compressor not only increases the pressure in the intake system but also builds up pressure toward the mechanically driven compressor. This is undesirable in terms of the efficiency of the combustion engine.

[0005] WO 1999 / 17008 A1 discloses an internal combustion engine with an air supply system comprising a turbocharger and an electrically driven compressor. A first line extends from the electrically driven compressor, and a second line extends from the turbocharger to the intake manifold of the internal combustion engine. The first line and the second line open into a common line section upstream of the intake manifold. A valve element in the form of a flap is arranged at a junction point between the two lines.

[0006] DE 199 34 606 A1 also discloses an internal combustion engine with an exhaust gas turbocharger and an electrically driven compressor.

[0007] EP 0 369 189 A1 describes an internal combustion engine with an exhaust gas turbocharger and an additional mechanically driven compressor.

[0008] It is therefore an object of the present invention to provide a motor assembly which is particularly efficient in operation.

[0009] This object is achieved according to the invention by an engine assembly for an internal combustion engine of a motor vehicle, comprising at least one exhaust gas turbocharger with a mechanically driven turbine which is arranged in the exhaust branch of the internal combustion engine, and a compressor which is mechanically driven by the turbine and which is in fluid communication with an intake tract of the internal combustion engine via a first line in order to supply charged air to the intake tract and to increase a pressure in the intake tract of the internal combustion engine, and at least one electrically driven compressor which is in fluid communication with an intake tract of the internal combustion engine via a second line in order to supply charged air to the intake tract and to increase a pressure in the intake tract of the internal combustion engine, wherein the first line and the second line open into one another at a junction point and a common line runs from the junction point to the intake tract.At least one valve element is arranged between the mechanically driven compressor and the junction point, which is designed to either open or close a flow path from the mechanically driven compressor to the intake tract. The at least one valve element is designed to be active.

[0010] In this way, the mechanically driven compressor and the electrically driven compressor can be avoided from competing with each other, thus increasing the efficiency of the engine assembly.

[0011] An active valve element has its own controllable drive motor and is, for example, electrically driven, which means that the direction of movement of the valve element can be selected relatively freely, taking into account the installation space situation.

[0012] The exhaust gas turbine uses the residual energy of the exhaust gases to drive the mechanically driven compressor, thereby increasing the air flow in the combustion engine and reducing the intake work of a piston in the combustion engine.

[0013] According to a preferred embodiment, the valve element opens the flow path from the mechanically driven compressor to the intake tract when the electrically driven compressor is inactive and closes the flow path when the electrically driven compressor is active. This ensures that the power of the electrically driven compressor, apart from the usual, unavoidable losses, is used exclusively to build pressure in the intake tract. In particular, it prevents the electrically driven compressor from driving the exhaust turbine of the exhaust gas turbocharger.

[0014] The at least one valve element is, for example, a flap that, in a closed position, closes the flow path from the mechanically driven compressor to the intake tract and, in an open position, opens the flow path. A flap represents a mechanically simple solution for selectively closing or opening a flow path.

[0015] According to a preferred embodiment, the valve element is subjected to a preload force in its closed position. This has the advantage that the valve element automatically moves into a closed position in the lower speed range of the internal combustion engine. In particular, the valve element is only moved into the open position when the mechanically driven compressor generates sufficient pressure to push the valve element into the open position against the preload force.

[0016] In order to generate a preload force on the valve element in a mechanically simple and cost-effective manner, the valve element can be biased into its closed position by a spring force.

[0017] For example, a cooler is located between the mechanically driven compressor and the valve element. The cooler allows a larger air mass to be transported into the intake tract of the combustion engine at the same pressure because the specific volume of the gas decreases upon cooling.

[0018] According to a further embodiment, a throttle valve is arranged in the common line leading to the intake tract. The throttle valve regulates the amount of air supplied to the combustion engine. This throttle valve can also be moved by a separate, controllable motor.

[0019] Further advantages and features of the invention will become apparent from the following description and the accompanying drawings, to which reference is made. In the drawings: - Fig. 1 a diagram of an engine assembly according to the invention and - Fig. 2 a diagram of another embodiment of a motor assembly according to the invention.

[0020] Fig. Figure 1 shows a diagram of an engine assembly 10 according to the invention for an internal combustion engine, in particular for a three-cylinder engine. The engine assembly 10 comprises a mechanically driven compressor 12, which is arranged in an exhaust branch 14 of the engine assembly, and an electrically driven compressor 16.

[0021] The mechanically driven compressor 12 is a component of an exhaust gas turbocharger 18. The operation of an exhaust gas turbocharger is well known in the art. The exhaust air drives a turbine 20, which in turn drives a compressor wheel of the mechanically driven compressor 12 via a shaft 22.

[0022] The electrically driven compressor 16 is driven by an electric motor 24 which is controlled by the engine control unit.

[0023] In order to supply charged air to an intake tract 26 of the internal combustion engine and to increase a pressure in the intake tract 26, the mechanically driven compressor 12 is in fluid communication with the intake tract 26 of the internal combustion engine via a first line 28.

[0024] The electrically driven compressor 16 is fluidly connected to the intake tract 26 of the internal combustion engine via a second line 30 in order to also supply supercharged air to the intake tract and increase the pressure in the intake tract 26 of the internal combustion engine. The electrically driven compressor 16 is particularly active when the pressure in the exhaust branch 14 is insufficient to generate the necessary compression by the mechanically driven compressor 12. This primarily occurs in a lower speed range. This range is also referred to as turbo lag.

[0025] The first line 28 and the second line 30 merge at a junction 32, with a common line 34 extending from the junction 32 to the intake tract 26. This allows compressed air to be supplied to the intake tract 26 either by the mechanically driven compressor 12 or by the electrically driven compressor 16.

[0026] Between the mechanically driven compressor 12 and the node 32, at least one valve element 36 is arranged, which is designed to either open or close a flow path from the mechanically driven compressor 12 to the intake tract 26.

[0027] In particular, the valve element 36 opens the flow path from the mechanically driven compressor 12 to the intake tract 26 when the electrically driven compressor 16 is inactive, and closes the flow path from the mechanically driven compressor 12 to the intake tract 26 when the electrically driven compressor 16 is active. This prevents the two compressors 12, 16 from competing with each other and prevents the electrically driven compressor 16 from building up pressure toward the mechanically driven compressor 12. This would lead to pressure losses in the intake tract 26 and negatively impact the efficiency of the internal combustion engine. Fig. 1, the valve element 36 is shown in a position in which it closes the flow path from the mechanically driven compressor 12 to the intake tract 26.

[0028] The valve element 36 is active, meaning it is driven electrically, hydraulically, or pneumatically. The drive of the active valve element can also be controlled by the motor controller.

[0029] The valve element 36 is mounted, for example, so that it can pivot and / or move linearly.

[0030] In the embodiment shown, the valve element 36 is a flap that, in a closed position, closes the flow path from the mechanically driven compressor 12 to the intake tract 26 and, in an open position, opens the flow path. For this purpose, the flap is pivotally mounted.

[0031] Instead of one valve element 36, multiple valve elements 36 can also be provided, for example, two valve elements 36. This can be justified by the installation space conditions. In particular, with a pivotably mounted valve element 36, a certain amount of free space must be available to allow the required movement of the valve element 36. Specifically, during an opening movement, the valve element 36 must not strike surrounding installation space components before a required opening angle of the valve element 36 is reached to allow a sufficient air flow through. By providing multiple valve elements 36, they can have smaller geometric dimensions and can therefore be integrated more flexibly into an installation space environment.

[0032] In order to transport the largest possible air mass into the intake tract 26, a cooler 38 is arranged between the mechanically driven compressor 12 and the valve element 36. This is also an option.

[0033] In addition, a throttle valve 40 is optionally arranged in the common line 34 leading to the intake tract 26 in order to regulate the amount of air supplied to the combustion engine.

[0034] Fig. Figure 2 shows a diagram of another engine assembly 10 according to the invention for an internal combustion engine. In contrast to the Fig. The embodiment shown in Figure 1 is an engine assembly for a six-cylinder engine.

[0035] For identical structures with identical functions known from the above embodiment, the same reference numerals are used below and reference is made to the previous explanations, with the differences between the respective embodiments being discussed below in order to avoid repetition.

[0036] In an engine assembly 10 for a six-cylinder engine, as shown in Fig. 2, a plurality of exhaust gas turbochargers 18, each with a mechanically driven compressor 12, may be provided, in particular two exhaust gas turbochargers 18 arranged in parallel. This allows the individual exhaust gas turbochargers 18 to be smaller than when using a single exhaust gas turbocharger 18.

[0037] The second mechanical compressor 12, like the first mechanical compressor 12, is fluidly connected to the intake tract 26 of the internal combustion engine via an additional line 28 to supply charged air to the intake tract 26. The additional line 28 also opens into the line 30 leading from the electrically driven compressor 16 to the intake tract at a junction 32.

[0038] By using two smaller exhaust gas turbochargers 18 with correspondingly lower moments of inertia instead of one larger exhaust gas turbocharger 18, the response of the combustion engine and the efficiency of the entire system can be improved.

[0039] The invention is not limited to the described embodiments. For example, it is also possible to provide more than two exhaust gas turbochargers to achieve further improvement. Furthermore, the internal combustion engine can also be a two-cylinder, four-cylinder, or five-cylinder engine.

Claims

[1] Engine assembly (10) for an internal combustion engine of a motor vehicle, comprising at least one exhaust gas turbocharger (18) with a mechanically driven turbine (20) arranged in the exhaust branch (14) of the internal combustion engine, and a compressor (12) mechanically driven by the turbine (20) which is in fluid communication with an intake tract (26) of the internal combustion engine via a first line (28) in order to supply charged air to the intake tract (26) and to increase a pressure in the intake tract (26) of the internal combustion engine, and at least one electrically driven compressor (16) which is in fluid communication with an intake tract (26) of the internal combustion engine via a second line (30) in order to supply charged air to the intake tract (26) and to increase a pressure in the intake tract (26) of the internal combustion engine, wherein the first line (28) and the second line (30) open into one another at a junction point (32) and, starting from the junction point (32), a common line (34) runs to the intake tract (26), and wherein at least one valve element (36) is arranged between the mechanically driven compressor (12) and the node (32), which valve element is designed to either open or close a flow path from the mechanically driven compressor (12) to the intake tract (26), characterized by that the at least one valve element (36) is designed to be active. [2] Motor assembly (10) according to claim 1, characterized by that the valve element (36) opens the flow path from the mechanically driven compressor (12) to the intake tract (26) when the electrically driven compressor (16) is inactive and closes it when the electrically driven compressor (16) is active. [3] Engine assembly (10) according to one of the preceding claims, characterized by that the at least one valve element (36) is a flap which, in a closed position, closes the flow path from the mechanically driven compressor (12) to the intake tract (26) and, in an open position, releases the flow path. [4] Engine assembly (10) according to one of the preceding claims, characterized by that the valve element (36) is subjected to a prestressing force in its closed position. [5] Motor assembly (10) according to claim 4, characterized by that the valve element (36) is biased into its closed position by a spring force. [6] Engine assembly (10) according to one of the preceding claims, characterized by , a cooler (38) is arranged between the mechanically driven compressor (12) and the valve element (36). [7] Engine assembly (10) according to one of the preceding claims, characterized bythat a throttle valve (40) is arranged in the common line (34) leading to the intake tract (26).

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