Patent ID: 12258915

DETAILED DESCRIPTION

Aspects set forth below represent the necessary information to enable those skilled in the art to practice the inventive concept.

The inventive concept may seek to improve an overall efficiency of an engine system with parallel turbo arrangements. A technical benefit may include that surge may be avoided for the compressors of the parallel turbo arrangements.

Turning toFIG.1which is an exemplary illustration of a vehicle1according to one example. The vehicle1inFIG.1is exemplified as a truck, but the below described inventive concept may be provided in other vehicles, such as e.g. working machines, buses, cars, etc. The vehicle1comprises an internal combustion engine10. The internal combustion engine10is preferably a hydrogen internal combustion engine. In such case, the hydrogen internal combustion engine receives hydrogen gas for combustion in the combustion chamber(s). As will be evident from the below description, the vehicle1further comprises an engine system100connected to the internal combustion engine10. The engine system100also comprises a control unit140. The control unit140comprises a processor device configured to control the engine system100as will be described in further detail below.

In order to describe the engine system100in further detail, reference is now made toFIG.2, which is an exemplary illustration of the engine system100according to one example. As can be seen, the engine system100is connected to the internal combustion engine10. The exemplified internal combustion engine10comprises a first cylinder package12, inFIG.2exemplified as comprising three combustion chambers14, a first inlet manifold16and a first exhaust manifold18. The exemplified internal combustion engine10also comprises a second cylinder package22, inFIG.2exemplified as comprising three combustion chambers24, a second inlet manifold26and a second exhaust manifold28. Air is thus fed into each of the first16and second26inlet manifolds, and combustion gas from the first cylinder package12is exhausted to the engine system100via the first exhaust manifold18, while combustion gas from the second cylinder package22is exhausted to the engine system100via the second exhaust manifold28.

The engine system100comprises a first turbo arrangement102and a second turbo arrangement202, where the first102and second202turbo arrangements are arranged in parallel with each other. In detail, the first turbo arrangement102comprises a first turbine106which is connected in downstream fluid communication with the first exhaust manifold18, and the second turbo arrangement202comprises a second turbine206which is connected in downstream fluid communication with the second exhaust manifold28. Accordingly, the first106and second206turbines receives combustion gases exhausted from the internal combustion engine10in parallel.

The first turbo arrangement102further comprises a first compressor110operably connected to the first turbine106. In particular, a first turbo shaft112is connecting the first turbine106and the first compressor110to each other. The first turbine106is operated to rotate by the flow of combustion gases it receives, whereby the first compressor110rotates to pressurize a flow of air114fed into an inlet of the first compressor110. In addition to the flow of combustion gases exposing the first turbo arrangement102to achieve a rotational motion, the rotation of the first turbo shaft112can be controlled to increase and/or decrease by other means than the flow of combustion gases from the internal combustion engine10. For example, the rotation can be controlled by controlling the flow of exhaust gases fed to the first turbo, such as e.g. by means of bypass valve, or by using a variable turbo geometry (VTG). The rotation may also be controlled mechanically by a variable gear ratio. Preferably, and according to an example, the controllable first turbo arrangement102comprises a first electric machine120configured to control the rotational speed of the first turbo shaft112. The first turbo arrangement102may thus be referred to as a first electrically controlled turbo arrangement. According to an example, the first electric machine120is arranged between the first turbine106and the first compressor110, i.e. the first electric machine120is arranged in, or constitutes, the first turbo shaft112. Such first electric machine120preferably comprises a first rotor and a first stator.

The first electric machine120is preferably connected to the above described control unit140. Thus, the processor device of the control unit140is configured to control the rotational speed of the first turbo arrangement102. The first electric machine120is also preferably connected to an energy storage150, preferably a battery, in order to receive electric power for its propulsion.

In a similar vein, the second turbo arrangement202further comprises a second compressor210operably connected to the second turbine206. In particular, a second turbo shaft212is connecting the second turbine206and the second compressor210to each other. The second turbine206is operated to rotate by the flow of combustion gases it receives, whereby the second compressor210rotates to pressurize a flow of air214fed into an inlet of the second compressor210. In addition to the flow of combustion gases exposing the second turbo arrangement202to achieve a rotational motion, the rotation of the second turbo shaft212can be controlled to increase and/or decrease by other means than the flow of combustion gases from the internal combustion engine10. Preferably, and according to an example, the controllable second turbo arrangement202comprises a second electric machine220configured to control the rotational speed of the second turbo shaft212. The second turbo arrangement202may thus be referred to as a second electrically controlled turbo arrangement. According to an example, the second electric machine220is arranged between the second turbo206and the second compressor210, i.e. the second electric machine220is arranged in, or constitutes, the second turbo shaft212. Such second electric machine220preferably comprises a second rotor and a second stator.

In a similar vein as the first electric machine120, the second electric machine220is preferably also connected to the above described control unit140. Thus, the processor device of the control unit140is configured to control the rotational speed of the second turbo arrangement202. The second electric machine220is also preferably connected to the energy storage150in order to received electric power for its propulsion.

After the combustion gases have entered the first106and second206turbines, the combustion gas155from the respective turbine converge at an interconnection portion160and flow towards an ambient environment. The flow of air114,214entering the first110and second210compressors is pressurized and converges at a position165downstream each of the first110and second210compressors and fed into the first16and second26inlet manifolds of the internal combustion engine.

The above described engine system100with the first102and second202turbo arrangements in parallel can efficiently improve pulse utilization of the engine system to thereby improve an overall efficiency of the engine system100. However, with turbines arranged in parallel, where the exhaust flow from the turbines converge at the position downstream the turbines, there is a risk that the turbo arrangements can negatively affect each other. For example, the pressure downstream the first turbine106may be lower than desired based on the pressure of the combustion gas exhausted from the second turbine206. This may lead to a situation where one of the first110and second210compressors are exposed to a phenomena commonly referred to as surge.

Reference is now made toFIGS.3A-3Bin order to describe a solution to at least partly mitigate the above potential problem associated with the first102and second202turbo arrangements in parallel.FIGS.3A-3Bare exemplary illustrations of a compressor map300according to one example. The compressor map300is preferably predefined and may be designed from compressor rig tests and/or predicted or estimated from simulations. The compressor map may be provided to the processor device of the control unit140.

The compressor map300defines an area302in which a compressor is operated to increase the pressure of the air upstream the engine. The vertical axis304represent the pressure, or pressure ratio, and the horizontal axis306represents the mass flow. The area302is delimited by a surge line310and a choke line312. When the pressure vs. mass flow of a compressor approaches the surge line310there is a risk that the compressor will stall. When the pressure vs. mass flow of a compressor approaches the choke line312, the compressor will choke, reducing the efficiency.

During operation of the above-described engine system100, the processor device of the control unit140determines a first pressure and a first mass flow of the air114pressurized by the first compressor110. The processor device can hereby determine a first compressor map position320, i.e. an instant compressor map position of the first compressor110. In a similar vein, the processor device also determines a second pressure and a second mass flow of air214pressurized by the second compressor210to determine a second compressor map position330. The second compressor map position330is thus an instant compressor map position of the second compressor210.

As can be seen inFIG.3A, the first compressor map position320is located close to the surge line310. In detail, a distance335between the first compressor map position320and the surge line310is below a predetermined threshold distance. The second compressor map position330is however located at a sufficient distance340from the surge line310, i.e. the distance340between the second compressor map position330and the surge line310is above the predetermined threshold distance.

In order to avoid the first compressor to stall, the processing circuitry controls the rotational speed of the first turbo arrangement102when determining that the distance335between the first compressor map position320and the surge line310is below the predetermined threshold distance. The first compressor map position320is hereby moved in the compressor map300as exemplified inFIG.3B, such that the distance between the first compressor map position320and the surge line310is above the predetermined threshold distance. Preferably, the processor device transmits data to the first electric machine120, whereby the first electric machine120controls the rotational speed of the first turbo arrangement.

In the example illustrated inFIGS.3A-3B, the rotational speed of the first turbo arrangement102is thus controlled such that the air pressurized by the first compressor110assumes an updated compressor map position as indicated inFIG.3B. According to a preferred example, the processor device may control the rotational speed of the first turbo arrangement102such that the first320and second330compressor map positions substantially coincide with each other.

The above description ofFIGS.3A-3Bfocus on an instant detection of the first compressor map position320being too close to the surge line310. However, the processor device may also receive map data of the topography of the upcoming route for the vehicle. The processor device may hereby estimate that the first320compressor map position will be moved towards the surge line310when arriving at the upcoming route. The processor device may hereby in advance control the rotational speed of the first turbo arrangement102such that the first compressor map position is moved even further away from the surge line310before the vehicle1arrives at the upcoming route. A safety margin preventing the first compressor to stall is obtained.

Turning now toFIG.4which is an exemplary illustration of an engine system100according to one example. The engine system100inFIG.4comprises the same features as described above in relation to the description ofFIG.2, which features will not be described in further detail.

In addition to the features described above in relation toFIG.2, the engine system100exemplified inFIG.4also comprises a secondary air pressure arrangement402. The secondary air pressure arrangement402is arranged in downstream fluid communication with each of the first110and second210compressors. In detail, the secondary air pressure arrangement402receives the air pressurized by the first110and second210compressors. The secondary air pressure arrangement402is arranged to pressurize the air even further before feeding the pressurized air to the inlet manifold.

The secondary air pressure arrangement402is preferably a mechanical supercharger which is connected and propelled by a crankshaft404of the internal combustion engine10. The exemplified mechanical supercharger402is depicted as connected to the crankshaft by a fixed gear ratio, although a variable gear ratio is also conceivable, as is schematically illustrated inFIG.5where a gear stage502and a planetary gear set504is arranged between mechanical supercharger402and the crankshaft404for presenting a non-limiting example of a variable gear ratio. The variable gear ratio may also be obtained by other means than what is depicted inFIG.5, such as a belt transmission, etc.FIG.5also illustrates the supercharger in the form of a roots blower. The roots blower should however also be applicable for the fixed gear stage depicted inFIG.4. The secondary air pressure arrangement402can preferably be of a displacement type. Such secondary air pressure arrangement402may be able to match a piston engine which in itself is also a displacement pump. A continuous additional boost can be obtained for substantially the entire range of speed of revolution of the engine. A displacement type of secondary air pressure arrangement402may be advantageously combined with a hydrogen internal combustion engine since the risk of backfire in the engine is reduced. A technical benefit of a secondary air pressure arrangement402positioned downstream the first and second turbines is that an over-charging of the engine system100can be obtained, whereby an improved efficiency can be provided, in particular for an internal combustion engine operating with a high charge pressure. In further detail, boosting is provided together with the force obtained from the first and second turbines, whereby the electric motors of the first and second turbos can be used for controlling the position of the first compressor map position. This may be particularly advantageous for a hydrogen internal combustion engine.

As exemplified inFIG.4, the engine system100also comprises a by-pass conduit406. Hereby, pressurized air from the first110and second210compressors can bypass, either partly or completely, the secondary air pressure arrangement402. The by-pass conduit406also comprises a by-pass valve408for controlling bypassing of the secondary air pressure arrangement402.

Moreover, the engine system100inFIG.4also comprises a charge air cooler410downstream the first110and second210compressors and upstream the secondary air pressure arrangement402. The temperature level of the air pressurized by the first110and second210compressors can hereby be reduced before entering the secondary air pressure arrangement402.

To summarize and to describe a method of controlling the engine system100according to one example, reference is made toFIG.6. As described above, during operation the processor device determines S1a first pressure and a first mass flow of air pressurized by the first compressor110, as well as a second pressure and a second mass flow of air pressurized by the second compressor210. By the first pressure and first mass flow, the processor device determines S2a first compressor map position320of the air pressurized by the first compressor110. Thereafter, the processor device controls S3the rotational speed of the first turbo arrangement102in response to the distance335between the first compressor map position320and the surge line310being below the predetermined threshold distance. The second turbo arrangement may obviously also be controlled if the second compressor map position is too close to the surge line.

Turning finally toFIG.7which is a schematic diagram of a computer system700for implementing examples disclosed herein. The computer system700is adapted to execute instructions from a computer-readable medium to perform these and/or any of the functions or processing described herein. The computer system700may be connected (e.g., networked) to other machines in a LAN, an intranet, an extranet, or the Internet. While only a single device is illustrated, the computer system700may include any collection of devices that individually or jointly execute a set (or multiple sets) of instructions to perform any one or more of the methodologies discussed herein. Accordingly, any reference in the disclosure and/or claims to a computer system, computing system, computer device, computing device, control system, control unit, electronic control unit (ECU), processor device, etc., includes reference to one or more such devices to individually or jointly execute a set (or multiple sets) of instructions to perform any one or more of the methodologies discussed herein. For example, control system may include a single control unit or a plurality of control units connected or otherwise communicatively coupled to each other, such that any performed function may be distributed between the control units as desired. Further, such devices may communicate with each other or other devices by various system architectures, such as directly or via a Controller Area Network (CAN) bus, etc.

The computer system700may comprise at least one computing device or electronic device capable of including firmware, hardware, and/or executing software instructions to implement the functionality described herein. The computer system700may include a processor device702(may also be referred to as a control unit), a memory704, and a system bus706. The computer system700may include at least one computing device having the processor device702. The system bus706provides an interface for system components including, but not limited to, the memory704and the processor device702. The processor device702may include any number of hardware components for conducting data or signal processing or for executing computer code stored in memory704. The processor device702(e.g., control unit) may, for example, include a general-purpose processor, an application specific processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA), a circuit containing processing components, a group of distributed processing components, a group of distributed computers configured for processing, or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. The processor device may further include computer executable code that controls operation of the programmable device.

The system bus706may be any of several types of bus structures that may further interconnect to a memory bus (with or without a memory controller), a peripheral bus, and/or a local bus using any of a variety of bus architectures. The memory704may be one or more devices for storing data and/or computer code for completing or facilitating methods described herein. The memory704may include database components, object code components, script components, or other types of information structure for supporting the various activities herein. Any distributed or local memory device may be utilized with the systems and methods of this description. The memory704may be communicably connected to the processor device702(e.g., via a circuit or any other wired, wireless, or network connection) and may include computer code for executing one or more processes described herein. The memory704may include non-volatile memory708(e.g., read-only memory (ROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), etc.), and volatile memory710(e.g., random-access memory (RAM)), or any other medium which can be used to carry or store desired program code in the form of machine-executable instructions or data structures and which can be accessed by a computer or other machine with a processor device702. A basic input/output system (BIOS)712may be stored in the non-volatile memory708and can include the basic routines that help to transfer information between elements within the computer system700.

The computer system700may further include or be coupled to a non-transitory computer-readable storage medium such as the storage device714, which may comprise, for example, an internal or external hard disk drive (HDD) (e.g., enhanced integrated drive electronics (EIDE) or serial advanced technology attachment (SATA)), HDD (e.g., EIDE or SATA) for storage, flash memory, or the like. The storage device714and other drives associated with computer-readable media and computer-usable media may provide non-volatile storage of data, data structures, computer-executable instructions, and the like.

A number of modules can be implemented as software and/or hard-coded in circuitry to implement the functionality described herein in whole or in part. The modules may be stored in the storage device714and/or in the volatile memory710, which may include an operating system716and/or one or more program modules718. All or a portion of the examples disclosed herein may be implemented as a computer program product720stored on a transitory or non-transitory computer-usable or computer-readable storage medium (e.g., single medium or multiple media), such as the storage device714, which includes complex programming instructions (e.g., complex computer-readable program code) to cause the processor device702to carry out the steps described herein. Thus, the computer-readable program code can comprise software instructions for implementing the functionality of the examples described herein when executed by the processor device702. The processor device702may serve as a controller or control system for the computer system700that is to implement the functionality described herein.

The computer system700also may include an input device interface722(e.g., input device interface and/or output device interface). The input device interface722may be configured to receive input and selections to be communicated to the computer system700when executing instructions, such as from a keyboard, mouse, touch-sensitive surface, etc. Such input devices may be connected to the processor device702through the input device interface722coupled to the system bus706but can be connected through other interfaces such as a parallel port, an Institute of Electrical and Electronic Engineers (IEEE) 1394 serial port, a Universal Serial Bus (USB) port, an IR interface, and the like. The computer system700may include an output device interface724configured to forward output, such as to a display, a video display unit (e.g., a liquid crystal display (LCD) or a cathode ray tube (CRT)). The computer system700may also include a communications interface726suitable for communicating with a network as appropriate or desired.

EXAMPLE LIST

Example 1

An engine system for a vehicle, the engine system comprising:a first turbo arrangement comprising a first turbine and a first compressor operably connected to each other, the first turbine being configured to be arranged in downstream fluid communication with an internal combustion engine,a second turbo arrangement comprising a second turbine and a second compressor operably connected to each other, the second turbine being configured to be arranged in downstream fluid communication with the internal combustion engine and in parallel with the first turbine, wherein the first and second turbo arrangements are individually controllable, anda control unit comprising a processor device operable to individually control a rotational speed of the first and second turbo arrangements, respectively, the processor device being configured to:determine a first pressure and a first mass flow of air pressurized by the first compressor, and a second pressure and a second mass flow of air pressurized by the second compressor,determine a first compressor map position of the air pressurized by the first compressor, the first compressor map position being a position, defined by the first pressure and the first mass flow, within a compressor map, the compressor map defining a surge line, andcontrol the rotational speed of the first turbo arrangement in response to a distance between the first compressor map position and the surge line being below a predetermined threshold distance.

Example 2

The engine system according to example 1, wherein the processor device is configured to, in response to the distance between the first compressor map position and the surge line being below the predetermined threshold distance, control the rotational speed of the first turbo arrangement such that the air pressurized by the first compressor assumes an updated compressor map position, wherein a distance between the updated compressor map position and the surge line is above the predetermined threshold distance.

Example 3

The engine system according to any one of examples 1 or 2, wherein the processor device is further configured to:determine a second compressor map position of the air pressurized by the second compressor, the second compressor map position being a position, defined by the second pressure and the second mass flow, within the compressor map.

Example 4

The engine system according to example 3, wherein the processor device is further configured:determine a first turbo rotational speed of the first turbo arrangement, the first turbo rotational speed providing a compressor map position of the air pressurized by the first compressor to substantially coincide with the second compressor map position, andcontrol the rotational speed of the first turbo arrangement by controlling the rotational speed of the first turbo arrangement to assume the first turbo rotational speed.

Example 5

The engine system according to any one of the preceding examples, wherein the first turbo arrangement is a first electrically controlled turbo arrangement.

Example 6

The engine system according to example 5, wherein the first electrically controlled turbo arrangement comprises a first electric motor between the first turbo and the first compressor.

Example 7

The engine system according to example 6, wherein the first electric motor is operably coupled to the processor device.

Example 8

The engine system according to any one of the preceding examples, wherein the second turbo arrangement is a second electrically controlled turbo arrangement.

Example 9

The engine system according to example 8, wherein the second electrically controlled turbo arrangement comprises a second electric motor between the second turbo and the second compressor.

Example 10

The engine system according to example 9, wherein the second electric motor is operably coupled to the processor device.

Example 11

The engine system according to any one of the preceding examples, further comprising a secondary air pressure arrangement arranged in downstream fluid communication with each of the first and second compressors.

Example 12

The engine system according to example 11, wherein the secondary air pressure arrangement is a mechanical supercharger operatively connectable to a crankshaft of the internal combustion engine.

Example 13

The engine system according to example 11, wherein the mechanical supercharger is operatively connectable to the crankshaft by a fixed gear ratio.

Example 14

The engine system according to example 11, wherein the mechanical supercharger is operatively connectable to the crankshaft by a variable gear ratio.

Example 15

The engine system according to any one of examples 11-14, further comprising a by-pass conduit bypassing the secondary air pressure arrangement.

Example 16

The engine system according to example 15, wherein the by-pass conduit comprises a by-pass valve.

Example 17

The engine system according to any one of the preceding examples, further comprising a charge air cooler arranged in downstream fluid communication with each of the first and second compressors.

Example 18

The engine system according to example 17 when dependent on any of examples 11-16, wherein the charge air cooler is arranged in upstream fluid communication with the secondary air pressure arrangement.

Example 19

The engine system according to any one of the preceding examples, wherein the processor device is further configured to:determine a lambda value of combustion gas exhausted from the internal combustion engine, andcontrol the rotational speed of at least one of the first and second turbo arrangements in response to the lambda value being outside a predetermined lambda threshold range.

Example 20

A vehicle comprising an internal combustion engine and an engine system according to any one of the preceding examples, wherein the engine system is connected to internal combustion engine.

Example 21

The vehicle according to example 20, wherein the internal combustion engine is a hydrogen internal combustion engine.

Example 22

The vehicle according to any one of examples 20 or 21, wherein the internal combustion engine comprises at least a first exhaust manifold and second exhaust manifold, the first compressor being arranged in downstream fluid communication with the first exhaust manifold, and the second compressor being arranged in downstream fluid communication with the second exhaust manifold.

Example 23

A method of controlling an engine system connected to an internal combustion engine, the engine system comprising:a first turbo arrangement comprising a first turbine and a first compressor operably connected to each other, the first turbine being arranged in downstream fluid communication with the internal combustion engine, anda second turbo arrangement comprising a second turbine and a second compressor operably connected to each other, the second turbine being arranged in downstream fluid communication with the internal combustion engine in parallel with the first turbine, wherein the first and second turbo arrangements are individually controllable,the method comprising:determining a first pressure and a first mass flow of air pressurized by the first compressor, and a second pressure and a second mass flow of air pressurized by the second compressor,determining a first compressor map position of the air pressurized by the first compressor, the first compressor map position being a position, defined by the first pressure and the first mass flow, within a predefined compressor map, wherein the predefined compressor map defines a surge line, andcontrolling the rotational speed of the first turbo arrangement in response to a distance between the first compressor map position and the surge line being below a predetermined threshold distance.

The operational steps described in any of the exemplary aspects herein are described to provide examples and discussion. The steps may be performed by hardware components, may be embodied in machine-executable instructions to cause a processor to perform the steps, or may be performed by a combination of hardware and software. Although a specific order of method steps may be shown or described, the order of the steps may differ. In addition, two or more steps may be performed concurrently or with partial concurrence.

The terminology used herein is for the purpose of describing particular aspects only and is not intended to be limiting of the inventive concept. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. It will be further understood that the terms “comprises,” “comprising,” “includes,” and/or “including” when used herein specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

It will be understood that, although the terms first, second, etc., may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element without departing from the scope of the present inventive concept.

Relative terms such as “below” or “above” or “upper” or “lower” or “horizontal” or “vertical” may be used herein to describe a relationship of one element to another element as illustrated in the Figures. It will be understood that these terms and those discussed above are intended to encompass different orientations of the device in addition to the orientation depicted in the Figures. It will be understood that when an element is referred to as being “connected” or “coupled” to another element, it can be directly connected or coupled to the other element, or intervening elements may be present. In contrast, when an element is referred to as being “directly connected” or “directly coupled” to another element, there are no intervening elements present.

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this inventive concept belongs. It will be further understood that terms used herein should be interpreted as having a meaning consistent with their meaning in the context of this specification and the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

It is to be understood that the present inventive concept is not limited to the aspects described above and illustrated in the drawings; rather, the skilled person will recognize that many changes and modifications may be made within the scope of the present inventive concept and appended claims. In the drawings and specification, there have been disclosed aspects for purposes of illustration only and not for purposes of limitation, the scope of the inventive concepts being set forth in the following claims.