Internal combustion engine system

Abstract

An internal combustion engine system includes: a two-stroke ICE having a cylinder with a cylinder wall and also having a reciprocating piston axially movable within the cylinder between a bottom dead center and a top dead center, the piston extending axially and having an axially upper portion having a top end forming part of a combustion chamber, the piston further has an axially lower portion, the cylinder comprising at least one intake port arranged at a top end of the cylinder and in fluid communication with the combustion chamber, the cylinder further comprising an exhaust port axially arranged at a location remote from the top end of the cylinder, allowing the intake port and the exhaust port to be fluidly separated by the piston, an axially upper portion of the piston comprises a plurality of compression rings for sealing the combustion chamber and an axially lower portion of the piston comprises at least one compression ring sealing along an area of the cylinder wall axially below the exhaust port in order to reduce leakage of blow-by gas from the combustion chamber into a crankcase volume portion of the ICE.

Description

Technical Field

[0001] The present disclosure generally relates to internal combustion engine systems. The present disclosure may be applicable to heavy vehicles, such as trucks, buses, and construction equipment, as well as other vehicle types. Although the present disclosure may be described with respect to trucks, the present disclosure is not limited to any particular vehicle. The internal combustion engine system may be applicable to other types of vehicles propelled by an internal combustion engine, such as automobiles and other light-duty and light-duty vehicles, for example. In addition, the internal combustion engine of the internal combustion engine system may typically be an internal combustion engine that operates with a hydrogen-based fuel. Background Art

[0002] In order to reduce negative climate impacts, there is a growing interest in reducing the use of fossil fuels. For example, when designing and selecting suitable internal combustion engine (ICE) systems and their engine components, the reduction of exhaust gases, the improvement of engine efficiency (i.e., the reduction of fuel consumption) and the reduction of engine noise levels are some of the criteria that have become more important. Furthermore, in the field of heavy vehicles such as trucks, there are many current environmental regulations that set specific requirements for vehicles, such as limits on the maximum permissible amount of exhaust pollution.

[0003] One possibility is to use hydrogen produced in a fossil-free manner as a fuel for internal combustion engines instead of, for example, fossil-based diesel. A large number of conventional existing diesel engines cannot operate properly if simply supplied with hydrogen instead of diesel; these engines must be modified to use hydrogen fuel. However, in order for such a modification of existing diesel engines to be economically feasible, the modification must not be too complicated and expensive. Examples of various ICE systems with pistons and piston rings are disclosed in US 2132223A, US 2096327A, US 4016839A, US 4399778A and US 9441573B1. Summary of the invention

[0004] According to a first aspect of the present disclosure, an internal combustion engine (ICE) system for a vehicle is provided. The ICE system includes a two-stroke ICE that can be operated by fuel. The ICE has at least one cylinder with a cylinder wall, and also has a reciprocating piston that can move in an axial direction between a bottom dead center (BDC) and a top dead center (TDC) in the cylinder. The piston extends in the axial direction. In addition, the piston has an axial upper portion with a top end, the top end is intended to form a part of a combustion chamber; and the piston also has an axial lower portion. The at least one cylinder at least partially defines the combustion chamber with the top end of the piston. The at least one cylinder includes at least one intake port arranged at the top end of the at least one cylinder. The at least one intake port is in fluid communication with the combustion chamber. In addition, the at least one cylinder includes an exhaust port, the exhaust port is axially arranged at a position away from the top end of the at least one cylinder, thereby allowing the at least one intake port and the exhaust port to be separated by the piston fluid. In addition, the axially upper portion of the piston includes a plurality of compression rings for sealing at the combustion chamber, and the axially lower portion includes at least one compression ring, which is configured to seal along an area of ​​the cylinder wall axially below the exhaust port so as to reduce leakage of blowby gases from the combustion chamber into the crankcase volume portion of the ICE.

[0005] A first aspect of the present disclosure may seek to provide an improved two-stroke ICE system to achieve more reliable and stable fuel combustion. Specifically, the present disclosure may seek to provide an ICE system that allows a more stable combustion of a fuel (such as a hydrogen-based fuel). Technical benefits may include more efficient transfer of exhaust gas from the combustion chamber to the exhaust system because blow-by gases are allowed to escape through the exhaust port, thereby reducing the risk of blow-by gases entering the crankcase volume. More specifically, at least one compression ring is arranged at the axially lower portion of the piston for limiting the pressure above the at least one compression ring from being transferred downward into the crankcase volume portion of the crankcase. The arrangement of the compression ring at the axially upper portion in combination with at least one compression ring at the axially lower portion is used to guide the gas that has passed through the compression ring at the axially upper portion through the exhaust port, while preventing or at least reducing the gas from returning to the combustion chamber through the exhaust port when the compression ring at the axially upper portion is located above the exhaust port. By arranging the piston in the cylinder, the risk of soot and oil particles mixing into the combustion process can be reduced.

[0006] By arranging the respective intake and exhaust ports of the cylinder at different positions, the corresponding piston will provide a blocking action between the intake and exhaust ports when the piston is at its top dead center, so that the hot part of the cylinder (exhaust port and cylinder wall / liner) will be completely separated from the combustible gas (usually corresponding to the air / fuel mixture).

[0007] Thus, the proposed ICE system enables a length scavenging system that separates the hot exhaust end of the cylinder from the cold intake end where combustibles are present. Thus, the risk of knocking can be significantly reduced using the proposed ICE system. To this end, the proposed ICE system is used to suppress the knocking and / or autoignition tendency of a fuel, such as a gaseous fuel, for example a hydrogen-based fuel.

[0008] Furthermore, the proposed two-stroke ICE (advantageously operated with hydrogen or any other gaseous fuel) provides an increased BMEP potential due to twice the firing frequency. Specifically, the two-stroke cycle enables the ICE to be operated at higher lambda values ​​while maintaining power density compared to a four-stroke ICE.

[0009] "Two-stroke operation" or "two-stroke mode" refers to a cycle of an internal combustion engine in which the piston moves two strokes (upward and downward) between TDC and BDC during only one revolution of the crankshaft in order to complete one complete working cycle. Typically, when an internal combustion engine is operated in a general two-stroke operation, its operation corresponds to engine operation that is repeated for every revolution of the crankshaft.

[0010] The fuel may be a gaseous fuel, a liquid fuel, or a combination thereof, such as a dual fuel having a first fuel and a second fuel.

[0011] Blow-by gases may typically contain combustible fuel as well as exhaust residues.

[0012] By arranging the exhaust port axially away from the top end of at least one cylinder, allowing at least one intake port and exhaust port to be fluidly separated by the piston, when the piston is located in the upper portion of the cylinder, at least one intake port and exhaust port are located at different positions and fluidly separated by the top end of the piston. Specifically, when the piston is at its top dead center, at least one intake port and exhaust port are located at different positions and fluidly separated by the top end of the piston. Therefore, the fluid communication between the combustion chamber and the exhaust port is controlled by the position of the piston (usually corresponding to the axial position of the piston along the axial direction).

[0013] Typically, the crankcase volume portion may be arranged axially below the exhaust port. Additionally, or alternatively, the crankcase volume may be arranged axially below the BDC of the piston.

[0014] In some examples, including at least one preferred example, optionally, at least one compression ring of the axially lower portion and a compression ring of the plurality of compression rings of the axially upper portion are arranged on the piston to provide an intermediate land where blow-by gases can be captured and discharged through the exhaust port. A technical benefit of the intermediate land may be to provide an improved scavenging process in terms of discharging blow-by gases through the exhaust port. In other words, the intermediate land also helps to guide gases that have passed through the compression ring at the axially upper portion through the exhaust port, while preventing or at least reducing gas from returning to the combustion chamber through the exhaust port when the compression ring at the axially upper portion is located above the exhaust port.

[0015] In some examples, including at least one preferred example, optionally, the at least one compression ring of the axially lower portion may be arranged on the piston such that the position of the at least one compression ring is axially below the exhaust port at the TDC of the piston. Thus, the at least one compression ring of the axially lower portion may be arranged on the piston such that the position of the at least one compression ring is never above the lower end of the exhaust port at the TDC of the piston.

[0016] In some examples, including at least one preferred example, optionally, a plurality of compression rings in the axially upper portion may be arranged on the piston such that the plurality of compression rings are positioned axially below the exhaust port at the BDC of the piston. This arrangement further helps to separate any crankcase gases and lubricating oil from the combustion gases and blow-by gases.

[0017] In some examples, including at least one preferred example, optionally, the plurality of compression rings of the axially upper portion includes at least two compression rings. Technical benefits may include improved sealing between the combustion chamber and the exhaust port during the combustion process.

[0018] In some examples, including at least one preferred example, optionally, the axially lower portion of the piston includes an oil control ring, which is axially arranged below at least one compression ring at the axially lower portion of the piston. The oil control ring is configured to distribute oil during movement of the piston along the cylinder wall. Technical benefits can include improved lubrication between the piston and the cylinder wall at the lower portion of the cylinder wall (i.e., below the location of the exhaust port). In addition, the arrangement of the oil control ring in the ICE system can reduce oil in the combustibles from the cylinder wall, which oil may spontaneously ignite.

[0019] In some examples, including at least one preferred example, optionally, any of the compression rings are defined by a uniform rectangular cross-section or a tapered cross-section.

[0020] In some examples, including at least one preferred example, optionally, at least one compression ring of the axially lower portion is a Napier-type compression ring. The use of Napier-type compression rings in ICE systems allows reliable reduction of leakage of blowby gases along the area of ​​the cylinder wall axially located below the exhaust port. The use of Napier-type compression rings may have a positive impact on overall fuel consumption compared to other types of compression rings.

[0021] In some examples, including at least one preferred example, optionally, the axially lower portion of the piston includes at least one compression ring, an additional compression ring in the form of a Napier-type compression ring, which is axially arranged below the at least one compression ring, and the axially lower portion also includes an oil control ring, which is axially arranged below the Napier-type compression ring.

[0022] In some examples, including at least one preferred example, optionally, at least one compression ring of the axially lower portion is arranged in a groove extending circumferentially around the piston skirt. It should be noted that any of the compression rings, oil control rings and other rings can generally be arranged in a corresponding groove extending around the piston in the circumferential direction.

[0023] The piston defines an envelope extending in axial and circumferential directions, having an upper region at its upper portion with an upper ring set with one or more compression rings and a lower region at its lower portion with a corresponding lower ring set.

[0024] The compression ring typically extends in a circumferential direction around the piston.

[0025] Furthermore, the ICE system is a spark-ignition ICE system, at least one cylinder having an ignition source arranged in a combustion chamber.

[0026] In some examples, including at least one preferred example, optionally, the ICE system includes an injector device for injecting fuel, the injector device being arranged in the combustion chamber.

[0027] In some examples, including at least one preferred example, intake air flow through at least one intake port may optionally be controlled by an intake control valve.

[0028] In some examples, including at least one preferred example, optionally, the at least one cylinder is a first cylinder, and the piston is a first piston, and the ICE also has a second cylinder, the second cylinder forms a pair of cylinders with the first cylinder, the second cylinder accommodates a corresponding reciprocating second piston operable between a bottom dead center and a top dead center, and also at least partially defines a second combustion chamber with the top end of the second piston, wherein the second cylinder also includes a corresponding ignition source arranged in the second combustion chamber, at least one corresponding intake port arranged at the top end of the second cylinder and connected to the second combustion chamber fluid, and also includes a corresponding exhaust port, the corresponding exhaust port is axially arranged at a position away from the top end of the second cylinder, thereby allowing the at least one corresponding intake port and the corresponding exhaust port to be separated by the second piston fluid.

[0029] In some examples, including at least one preferred example, optionally, the first cylinder and the second cylinder may be separated from each other by 180 crank angle degrees.

[0030] By providing a pair of first and second cylinders arranged 180 degrees of crank angle apart from each other, the two cylinders may provide a 180 degree cycle separation regardless of the ICE and cylinder arrangement / configuration.

[0031] In some examples, including at least one preferred example, optionally, the pair of first and second cylinders may be arranged 180 degrees of crank angle apart from each other to provide a 180 degree combustion phasing separation.

[0032] In some examples, including at least one preferred example, optionally, the ICE system further comprises an intake duct having a positive displacement device, the positive displacement device being configured to receive intake air and supply it to at least one pair of cylinders, the positive displacement device also being arranged in the intake duct to separate an upstream intake duct of the intake duct from a downstream plenum chamber, the downstream plenum chamber being in fluid communication with each of the first cylinder and the second cylinder of the at least one pair of cylinders. By arranging the positive displacement device in the intake duct, the displacement device is arranged to eliminate or at least reduce the risk of pressure pulses being transmitted backward from the combustion chamber to the upstream intake duct of the intake duct. Thus, the intake port is mechanically isolated from the intake duct. Thus, the positive displacement device is arranged to seal the cylinder and the downstream intake plenum chamber from the upstream intake duct of the intake duct (intake manifold) in the event of a flashback. Moreover, by the arrangement and configuration of the displacement device in the intake duct, the displacement device can still provide a uniform flow by alternately supplying the cylinder pairs.

[0033] To this end, the ICE system may provide a separate intake plenum for each pair of cylinders with a 180 degree combustion phasing separation, wherein the intake duct has a close coupled positive displacement device for each pair of cylinders. Such an ICE system may help reduce ignition time and reduce the risk of flashback in the intake system of the ICE system.

[0034] It should be noted that the proposed ICE system may not be limited to a system with a pair of cylinders, but may also be implemented in four cylinders, six cylinders, etc. Thus, the proposed ICE system may have at least two cylinders, but multiples of two cylinders are also possible.

[0035] In some examples, including at least one preferred example, optionally, the intake control valve of the first cylinder can be controlled in association with movement of the first piston and the intake control valve of the second cylinder can be controlled in association with movement of the second piston so that during crankshaft rotation of the ICE, fluid communication between the corresponding combustion chamber and the downstream plenum chamber is selectively opened and closed.

[0036] In some examples, including at least one preferred example, the plenum may optionally include an air inlet configured for fluid communication with the positive displacement device and a plurality of outlets configured for fluid communication with intake ports of the first and second cylinders.

[0037] In some examples, including at least one preferred example, the ICE system may optionally include a common crankcase housing for the pair of cylinders, or the ICE system may include multiple groups of paired cylinders and the ICE system includes a common crankcase housing for all cylinders of the ICE.

[0038] Furthermore, the ICE system is a hydrogen ICE system configured to operate with a gaseous fuel including a hydrogen-based gaseous fuel.

[0039] ICE systems may benefit all forced scavenging two-stroke ICE systems including but not limited to compression ignition fuel engines such as H2 ICE systems with diesel pilot injection in two-stroke mode.

[0040] In some examples, including at least one preferred example, the fuel may optionally be a gaseous fuel. One example of a gaseous fuel is a hydrogen-based fuel.

[0041] In some examples, including at least one preferred example, optionally, the fuel is a liquid fuel. An example of a liquid fuel is an NH3-based fuel.

[0042] In some examples, including at least one preferred example, the ignition source may alternatively be any of a spark plug and a glow plug.

[0043] In some examples, including at least one preferred example, each of the intake control valves and corresponding intake control valves may optionally be arranged to open and close a fluid passage of a corresponding intake port, thereby controlling fluid flow to a corresponding combustion chamber.

[0044] In some examples, including at least one preferred example, the ICE system may optionally include a fuel injector arrangement disposed in a downstream plenum of the intake duct to provide fuel injection upstream of the intake ports of the first cylinder and the second cylinder. Technical benefits may include improved fuel injection into the combustion chamber of the ICE. Here, the ICE system is configured to provide port injection of gaseous fuel or liquid fuel.

[0045] The use of port injection allows for a homogeneous mixture, thereby improving knock and auto-ignition control and also helping to reduce emissions.

[0046] Alternatively, a fuel injector device may be arranged in each of the combustion chambers of the first cylinder and the second cylinder, respectively.

[0047] In some examples, including at least one preferred example, optionally, the fuel injector device may be controllable to inject fuel into the intake port and the corresponding intake port so that a pressure pulse is generated in the downstream plenum and then enters the corresponding combustion chamber. Technical benefits may include improved scavenging effects. Therefore, the ICE system is configured to provide a scavenging effect through the injection timing of the intake port. The fuel injector device is generally controllable in response to a predetermined fuel injection event.

[0048] In some examples, including in at least one preferred example, the fuel injector device can optionally be controllable to provide sequential fuel injection to the first cylinder and the second cylinder to allow active cylinder scavenging during the second half of the corresponding intake stroke of the corresponding cylinder in the first cylinder and the second cylinder.

[0049] In some examples, including at least one preferred example, optionally, the intake control valve of the first cylinder can be controlled in association with the movement of the first piston and the intake control valve of the second cylinder can be controlled in association with the movement of the second piston, so that during the crankshaft rotation of the ICE, the fluid communication between the corresponding combustion chamber and the plenum chamber is selectively opened and closed. Technical benefits can include further reducing the risk of flashback.

[0050] In some examples, including at least one preferred example, optionally, the plenum chamber may include an air inlet in fluid communication with the positive displacement device and a plurality of outlets configured to be in fluid communication with the intake ports of the first cylinder and the second cylinder. Technical benefits may include an improved air supply system for supplying air to the cylinders. For example, the plenum chamber is a Siamese-shaped design.

[0051] In some examples, each of the cylinder heads of the first cylinder and the second cylinder may have multiple intake control valves. The number of intake control valves per cylinder may generally be any practical number and may generally be selected based on the cylinder type and the ICE type. For example, each of the cylinder heads may have four intake control valves. Technical benefits may include a further improved air supply system for supplying air to the cylinders. The configuration of an ICE system with four intake control valves per cylinder may be particularly beneficial for a two-stroke operated ICE system, which typically has a shorter intake cycle than a four-stroke ICE system. The configuration of an ICE system with four intake control valves per cylinder allows for an increased intake rate into the combustion chamber of the cylinder. In addition, it may improve the scavenging phase of expelling (pushing out) the exhaust gas in a uniform pressure wave manner.

[0052] In some examples, including at least one preferred example, the intake control valve can optionally be configured to provide variable valve actuation. Technical benefits can include improved control of an air supply system that supplies air to the cylinders during operation of an ICE system. Variable valve actuation can also allow for adjustment of phasing (valve timing) to achieve more optimized pulse capture and efficiency in synchronization with fuel injection and corresponding pulses in the air chamber.

[0053] In some examples, including at least one preferred example, the positive displacement device may optionally be a variable positive displacement device configured to operate in a variable manner. Technical benefits may include improved control of the flow and / or pressure of air flowing to the cylinders during operation of the ICE system. In addition, the variable drive positive displacement device allows for greater flexibility in the intake system of the ICE system and improves the functionality of the ICE system as a whole.

[0054] In some examples, including at least one preferred example, optionally, the pair of first and second cylinders are arranged as a pair of adjacent cylinders. In this way, the volumetric efficiency of the ICE system can be further improved.

[0055] In some examples, including at least one preferred example, the ICE system may optionally further include additional pairs of cylinders with corresponding intake ducts and positive displacement devices.

[0056] In some examples, including at least one preferred example, the exhaust port may optionally be arranged in fluid communication with an exhaust conduit arranged to convey exhaust gas away from the cylinder.

[0057] In some examples, including at least one preferred example, the ICE system may optionally further include a turbocharger device having a turbocharger turbine operably connected to a turbocharger compressor, wherein the turbocharger compressor is arranged in an intake duct leading to an intake duct, and wherein the turbocharger turbine is arranged in the exhaust duct to drive the turbocharger compressor.

[0058] In some examples, including at least one preferred example, the ICE system may optionally further include an exhaust gas recirculation (EGR) system comprising an EGR conduit arranged to connect the exhaust duct and the intake duct so as to allow exhaust gas to be recirculated through the cylinders during operation of the ICE.

[0059] In some examples, including at least one preferred example, the EGR system may optionally also include a corresponding positive displacement device.

[0060] In some examples, including at least one preferred example, the EGR conduit may optionally be connected to the intake conduit at a location downstream of the turbocharger compressor and further connected to the exhaust conduit at a location upstream of the turbocharger turbine.

[0061] In some examples, including at least one preferred example, the ICE system may optionally be a hydrogen ICE system configured to operate with a gaseous fuel including a hydrogen-based gaseous fuel. Therefore, the proposed ICE system may be particularly useful for hydrogen ICE systems. Hydrogen-based fuels typically have higher auto-ignition temperatures, but require lower ignition energies only when a spark (or hot surface or particles) is present. However, the low ignition energy may pose some challenges to the ICE, for example, it may be difficult to use a cylinder head where the hot exhaust ports / valves are located in the same combustion chamber as the intake ports / valves or are located near the compressed air / fuel mixture before ignition. The technical benefits of using the proposed ICE system with hydrogen-based fuels may include more reliable and robust hydrogen ICE systems.

[0062] In some examples, including at least one preferred example, optionally, the ICE system can be configured to jointly control the positive displacement device and the intake valve to control the flow of gas to the combustion chamber. The positive displacement device and the intake valve can be controlled by a controller. In addition or alternatively, the positive displacement device can be controlled by the controller, and the intake valve can be controlled by one or more camshafts and / or the intake valve can be controlled by one or more corresponding actuators of the intake valve.

[0063] In some examples, including at least one preferred example, the ICE system may optionally further include a controller configured to terminate fuel injection during the intake phase and prior to intake valve closing, whereby the remainder of the intake phase includes purging the plenum of fuel and subsequently introducing fresh air into the plenum by operating the positive displacement device.

[0064] In some examples, including at least one preferred example, the ICE system may optionally include multiple groups of paired cylinders having corresponding intake ducts with corresponding positive displacement devices.

[0065] According to a second aspect of the present disclosure, there is provided a vehicle comprising an internal combustion engine system according to the first aspect and / or any one of the examples of the first aspect.

[0066] The disclosed aspects, examples (including any preferred examples), and / or the appended claims may be appropriately combined with each other, which is obvious to any person skilled in the art. Additional features and advantages are disclosed in the detailed description, claims, and drawings, and in part will be obvious to those skilled in the art or recognized by practicing the disclosure as described herein. BRIEF DESCRIPTION OF THE DRAWINGS

[0067] Examples are described in more detail below with reference to the accompanying drawings.

[0068] Figure 1 is an exemplary embodiment of the present disclosure, which includes a side view of a vehicle in the form of a truck according to one example.

[0069] Figure 2a An internal combustion engine system according to one example is shown.

[0070] Figure 2b An internal combustion engine system according to one example is shown.

[0071] Figure 2c An internal combustion engine system according to one example is shown.

[0072] Figure 3 A cross-sectional view of a piston compression ring of an internal combustion engine system is shown according to one example.

[0073] FIG. 4A to FIG. 4D Shows Figure 2a to Figure 2c An example of a combustion cycle for an internal combustion engine system in FIG. DETAILED DESCRIPTION

[0074] The detailed description set forth below provides information and examples of the disclosed technology in sufficient detail to enable those skilled in the art to practice the disclosure.

[0075] The present disclosure may seek to provide an improved two-stroke ICE system to achieve more reliable and stable fuel combustion. Technical benefits may include more efficient transfer of exhaust gas from the combustion chamber to the exhaust system, as blow-by gases are allowed to escape more directly through the exhaust ports of the ICE system, thereby reducing the risk of blow-by gases entering the crankcase volume. In addition, the proposed ICE system allows for a reduction in oil in the combustibles from the cylinder walls.

[0076] Figure 1 is an exemplary embodiment of the present disclosure, which includes a side view of a vehicle 1 in the form of a truck according to one example.

[0077] Although the illustrated embodiment shows a truck, the present disclosure may relate to any vehicle, such as an automobile, bus, industrial vehicle, boat, ship, etc., in which power may be derived from an internal combustion engine.

[0078] The vehicle 1 includes an internal combustion engine system 10. The internal combustion engine system may generally be referred to as the ICE system 10 herein. In addition, the vehicle 1 may also include a controller 90. The controller here is part of the control system. The controller 90 may be part of the ECU of the vehicle 1. The controller 90 includes a processing circuit 91 configured to control the ICE system 10, as described herein.

[0079] The following will combine Figure 2a to Figure 2c An ICE system 10 is described, in which an example of an ICE system is shown. Figure 3 and FIG. 4A to FIG. 4D Describes further details of the ICE system. More specifically, Figure 2a to Figure 2b An example of an ICE system 10 is shown. Purely by way of example, Figure 2a to Figure 2c The ICE system 10 can be used for Figure 1 Vehicle 1.

[0080] The ICE system 10 includes a two-stroke ICE 20. Here, the ICE 20 can operate with a gaseous fuel 50. In other examples, the ICE 20 can operate with a liquid fuel. An example of a gaseous fuel is a hydrogen-based fuel. An example of a liquid fuel is an NH3-based fuel. Other examples of liquid fuels are LNG, LPG, gasoline, etc.

[0081] Figure 2c Shows Figure 2a to Figure 2b Further details of the ICE system 10 are shown in . Figure 2c Further details are provided in the ICE system to describe the optional features. Figure 2a to Figure 2b The described ICE system 10 may be implemented in any type of two-stroke ICE 12 .

[0082] Now go to Figure 2a and Figure 2b , shows an example of an ICE 20 having at least one cylinder 30 with a cylinder wall 30a. Typically, the at least one cylinder is a first cylinder 30 of the ICE 20. Thus, the ICE 20 includes at least the first cylinder 30. However, the ICE 20 may typically include a plurality of cylinders, such as a pair of a first cylinder and a second cylinder, as described with respect to Figure 2c The cylinder 30 extends in an axial direction A and a radial direction R. The cylinder 30 also has an extension in a circumferential direction C.

[0083] Thus, the cylinder wall 30a extends in the axial direction A and the circumferential direction C. The cylinder wall 30a is the inner wall of the cylinder 30. In addition, the inner wall of the cylinder may be provided by a so-called cylinder liner, as is known in the art. Thus, the cylinder wall 30a may be a part of the cylinder liner.

[0084] The cylinder 30 here also includes a cylinder head 30b. Here, the cylinder head 30b defines the uppermost part of the cylinder 30, as seen in the axial direction A.

[0085] For example, the cylinder head 30b may have a substantially flat bottom inner surface. Other examples of cylinder heads are also possible. Therefore, given the design of the cylinder head 30b, the design of the combustion chamber may be adopted in several different ways. Therefore, the design of the cylinder head and cylinder in the figure is provided only for illustrating one example of cylinder design.

[0086] The ICE 20 also includes a reciprocating piston 31. The reciprocating piston 31 is movable in the axial direction A within the cylinder 30. The reciprocating piston 31 is movable in the axial direction A between a bottom dead center (BDC) and a top dead center (TDC) within the cylinder 30. For ease of reference, the reciprocating piston 31 is hereinafter simply referred to as a piston.

[0087] Figure 2a is a cross-sectional view of a piston 31 disposed within a cylinder 30 . Figure 2a The reciprocating piston 31 is shown at its top dead center (TDC). Figure 2b is another cross-sectional view of the piston 31 disposed within the cylinder 30 . Figure 2b The reciprocating piston 31 is shown at its bottom dead center (BDC).

[0088] The piston 31 extends in an axial direction A and a radial direction R. The diameter of the piston 31 is smaller than the inner diameter of the cylinder 30, as shown in FIG. 2. In addition, the piston 31 extends circumferentially along a circumferential direction C. The piston 31 also has a longitudinal center axis Z A1 (See Figure 2c ), which may generally be indicated as the axial center axis hereinafter.

[0089] As used herein, the terms "radial" or "radially" refer to a relative direction that is substantially perpendicular to the axial centerline of a particular component. Additionally, the terms "longitudinal," "longitudinally," "axially," or "axially" refer to a relative direction that is substantially parallel and / or coaxially aligned with the axial centerline of a particular component. Additionally, the terms "longitudinal," "longitudinally," "axially," or "axially" refer to a direction that extends at least between the axial ends of a particular component, typically along the device or component thereof in the direction of longest extension of the device and / or component. The terms "vertical" and "vertically" generally correspond to an axial direction.

[0090] Similarly, terms such as “upper”, “above” and “top” as well as “lower”, “bottom” and “below” generally refer to the relative positions of parts or components with respect to the axial direction A.

[0091] Furthermore, the piston 31 extends in the axial direction A. Furthermore, the piston 31 also extends in the circumferential direction. To this end, the piston 31 comprises an envelope surface extending in the axial direction A and in the circumferential direction C.

[0092] Furthermore, the piston 31 comprises an axially upper portion 74. The axially upper portion 74 here refers to the portion forming the piston crown. In other words, the axially upper portion 74 is generally the piston crown of the piston 31. The axially upper portion 74 comprises a top end 33. The top end 33 is intended to form a part of the combustion chamber 32. The top end 33 here is a piston head. In other words, the piston 31 has a top end 33 in the form of a piston head.

[0093] Furthermore, the piston 31 comprises an axially lower portion 75 . The axially lower portion 75 is arranged axially below the axially upper portion 74 .

[0094] In this example, the axially upper portion 74 and the axially lower portion 75 are parts of a one-piece piston. However, the piston can also be a multi-piece piston comprising a plurality of individual parts that together form the piston. The plurality of pieces of the piston can be made of the same material, or of different materials.

[0095] The axially upper portion 74 and the axially lower portion 75 are opposite portions of the piston 31, as shown in FIG. Figure 2a More specifically, as viewed in the axial direction A of the piston 31 , the axially upper portion 74 and the axially lower portion 75 are opposite portions of the piston 31 .

[0096] The piston 31 here generally further comprises a piston skirt 70 extending in the axial direction A. The piston skirt 70 also extends in the circumferential direction C of the piston 31. The piston skirt 70 defines an envelope surface extending in the axial direction and the circumferential direction.

[0097] Therefore, the piston skirt 70 is also divided into an upper region located at the axial upper portion 74 and a lower region located at the axial lower portion 75 .

[0098] At least one cylinder 30 and the top end 33 (piston head) of the piston 31 partially define the combustion chamber 32. That is, at least one cylinder 30 and the piston head of the piston top partially define the combustion chamber 32. The combustion chamber 32 is arranged at the end of the cylinder 30 (i.e., the cylinder head 30b) so that the upper surface of the top end 33 defines the lower side of the combustion chamber 32. As described herein, the upper surface of the top end 33 of the axial upper portion 74 may be referred to as the piston head of the piston top.

[0099] The cylinder 30 here also includes an ignition source 34. The ignition source 34 is arranged in the first combustion chamber 32. The ignition source 34 is arranged in the cylinder 30 and is located at a position facing the combustion chamber 32. For example, the ignition source 34 is arranged at the upper end of the cylinder 30, such as Figure 2a As shown. Specifically, the ignition source 34 is arranged at the cylinder head 30b of the cylinder 30. Other arrangements of the ignition source are also conceivable. The ignition source 34 is configured to ignite, for example, injected hydrogen supplied via a fuel device, as described herein. For example, the ignition source is a spark plug. A spark plug is a device for transmitting electric current from an ignition system to a combustion chamber of a spark-ignition engine to ignite a compressed fuel / air mixture by an electric spark while maintaining combustion pressure within the engine.

[0100] It should be noted that the ICE system 10 is not limited to spark plug ICE systems, but may be applied to other types of ICE systems based on a diffusion combustion cycle.

[0101] Furthermore, the at least one cylinder 30 comprises at least one intake port 35 arranged at a top end 36 of the at least one cylinder 30. The top end 36 here is a component of the cylinder head 30b.

[0102] The air intake port 35 is configured to be in fluid communication with the combustion chamber 32 .

[0103] In addition, the flow of combustible gas through at least one intake port 35 can be controlled by an intake control valve 37. In this example, the combustible gas typically comprises a mixture of air and hydrogen (gaseous fuel) injected into the intake port. The intake control valve 37 is arranged to open and close the fluid passage of the intake port 35, thereby controlling the flow of fluid to the combustion chamber 32.

[0104] Furthermore, the at least one cylinder 30 includes an exhaust port 38 axially disposed away from a top end 36 of the at least one cylinder 30 , thereby allowing the at least one intake port 35 and the exhaust port 38 to be fluidly separated by the piston 31 .

[0105] Therefore, when the first piston 31 is at its top dead center, the intake port 35 and the exhaust port 38 are located at different positions and are separated by the piston top 33 .

[0106] The exhaust port 38 is configured to discharge the combusted gas from the cylinder 30. The exhaust port 38 is arranged at a position away from the top end 33 of the first cylinder 30. Therefore, when the first piston 31 is at its TDC, the intake port 35 and the exhaust port 38 are located at different positions and are separated by the top end 33. In this context, the term "away" means that the exhaust port 38 is arranged in the direction Z (see FIG. 1 ) of the cylinder 30. Figure 2c ) is spaced apart from the top end 33, the direction Z corresponding to the axial direction A of the piston 31. The top end 33 is therefore considered to be a proximal portion of the cylinder 30. In other words, the piston 31 is arranged in the cylinder 30 for reciprocating movement along the central axis ZA1, where the central axis ZA1 extends in the direction Z. In other words, in this example, the axial direction A of the piston 31 corresponds to the direction Z (see Figure 2c ). Therefore, the center axis ZA1 is arranged parallel to the direction Z. Therefore, the exhaust port 38 is arranged at a position axially away from the top end 33 of the cylinder 30 in the axial direction A (corresponding to the direction Z here) of the cylinder 30 and the piston 31 .

[0107] For example, the exhaust port 38 is arranged at a lower middle portion of the cylinder 30 .

[0108] Go to again Figure 2a and Figure 2b , an axially upper portion 74 of the piston 31 includes compression rings 71, 72 for sealing the combustion chamber.

[0109] like Figure 2a and Figure 2b As further shown, the axially lower portion 75 includes at least one compression ring 78 configured to seal along a region 73 of the cylinder wall 30a axially below the exhaust port 38 to reduce leakage of blow-by gases from the combustion chamber 32 into the crankcase volume 69 of the ICE 20. In this document, blow-by gases generally refer to combustible fuel and exhaust residues. That is, blow-by gases contain combustible fuel and exhaust residues.

[0110] Thereby, the risk of soot and oil particles being mixed into the combustion process can be reduced. This arrangement of the ICE system can further help to reduce the ignition time while also reducing the risk of flashback in the intake system of the ICE system.

[0111] During the combustion process, the force of the high pressure gases compresses the compression rings 71, 72, 78 against the cylinder wall 30a, thereby providing an effective seal. This pressure pushing each of the rings is generally proportional to the combustion gas pressure.

[0112] The topmost compression ring 71 is used to seal any kind of leakage inside the combustion chamber 32 during the combustion process. Another compression ring 72 provides further sealing in a similar manner. Thus, the compression rings 71, 72 provide sealing above the piston 31 and prevent gas leakage from the combustion side.

[0113] With regard to the crankcase volume portion 69 , a variety of options are possible in the layout of the ICE system 10 .

[0114] Usually, if Figure 2a As shown, crankcase volume 69 is disposed axially below exhaust port 38 and generally axially below BDC of piston 31 .

[0115] For example, the ICE system 10 includes a common crankcase housing 65 for a pair of cylinders including cylinder 30. In this example, the common crankcase housing 65 includes a crankcase volume portion 69. Alternatively, the ICE system 10 includes multiple sets of paired cylinders, wherein the ICE system 10 includes a common crankcase housing for all cylinders of the ICE 20. In this example, the common crankcase housing includes a crankcase volume portion 69.

[0116] Turn again Figure 2a , at least one compression ring 78 of the axially lower portion 75 and a compression ring of the plurality of compression rings of the axially upper portion 74 are arranged on the piston 31 to provide an intermediate land 79, where blow-by gases can be captured and discharged through the exhaust port. Therefore, the piston 31 also includes an intermediate land 79. The intermediate land 79 extends in the axial direction A and the circumferential direction C of the piston 31. The intermediate land 79 is indicated as "intermediate land" because it extends axially between the compression rings 72 and 78. The intermediate land is a surface area on the piston skirt 70.

[0117] More specifically, if Figure 2a As shown, the intermediate land 79 extends in the axial direction A between the lowermost compression ring 72 of the plurality of compression rings of the axially upper portion 74 and the compression ring 78 of the axially lower portion 75 .

[0118] In some examples, the axially lower portion of the piston 31 includes at least one compression ring 78, an additional compression ring (not shown) disposed axially below the at least one compression ring 78, and an oil control ring 76 disposed axially below the Napier-type compression ring.

[0119] In some examples, the axially lower portion of the piston 31 includes at least one compression ring 78, an additional compression ring in the form of a Napier-type compression ring, which is axially arranged below the at least one compression ring 78; and also includes an oil control ring 76, which is axially arranged below the Napier-type compression ring.

[0120] Thus, in this example, the piston skirt 70 is defined by an axially upper portion 74, an axially lower portion 75, and an intermediate land 79 extending between the axially upper portion 74 and the axially lower portion 75. Other configurations are possible, such that the intermediate land 79 is an integral part of either portion 74 or 75.

[0121] More specifically, the piston 31 is provided with a piston skirt 70 , wherein an upper region of the piston skirt comprises an upper ring set with one or more compression rings 71 , 72 , while a lower region has a corresponding lower ring set with compression rings 78 .

[0122] like Figure 2a As shown, at least one compression ring 78 of the axially lower portion 75 is arranged on the piston 31 such that the position of the at least one compression ring 78 is axially below the exhaust port 38 at the TDC of the piston 31. More specifically, as shown in FIG. Figure 2a As shown, the compression ring 78 of the axially lower portion 75 is arranged on the piston 31 so that the compression ring 78 is axially located below the lower end 38b of the exhaust port 38 at TDC of the piston 31. Therefore, during the combustion cycle, as seen in the axial direction A, the compression ring 78 is never located above the exhaust port 38.

[0123] In other words, the at least one compression ring 78 of the axially lower portion 75 is arranged on the piston 31 such that the at least one compression ring 78 is never located above the lower end 38 b of the exhaust port 38 at TDC of the piston 31 .

[0124] In addition, in this example, Figure 2a and Figure 2b As depicted, the plurality of compression rings 71 , 72 of the axially upper portion 74 are arranged on the piston 31 such that the compression rings 71 , 72 are axially located below the exhaust port 38 at the BDC of the piston 31 .

[0125] Therefore, the compression ring 78 of the axially lower portion 75 is never located above the lower end 38b of the exhaust port 38 during the reciprocating movement of the piston 31 in the cylinder 30. Figure 2a As shown, the compression rings 71, 72 of the axial upper portion 74 always pass through the entire opening of the exhaust port 38 during the reciprocating movement of the piston 31, as shown in FIG. Figure 2b This generally means that the compression rings 71, 72 pass under the lower end 38b of the exhaust port 38 as the piston 31 travels from TDC to BDC. Figure 2b This is also shown.

[0126] In addition, the piston 31 and the cylinder 30 are also arranged here so that the axial length of the piston 31 relative to the axial length of the cylinder wall 30a ensures that during the reciprocating movement of the piston 31 in the cylinder 30, the compression ring 78 of the axial lower part 75 is never located above the lower end 38b of the exhaust port 38, and the compression rings 71, 72 of the axial upper part 74 always pass through the entire opening of the exhaust port 38 during the reciprocating movement of the piston 31.

[0127] For completeness, the exhaust port 38 also has an upper end 38a, such as Figure 2a and Figure 2b Thus, the opening of the exhaust port 38 is generally defined by the axial distance between the upper end 38a and the lower end 38b. Figure 2a and Figure 2b As shown, the intermediate land 79 is generally greater than the axial distance between the upper end 38a and the lower end 38b.

[0128] Therefore, the opening of the exhaust port 38 is opened and closed by the piston 31 (when reciprocating between BDC and TDC).

[0129] The plurality of compression rings 71, 72 of the axial upper portion 74 here include at least two compression rings. In other examples, the number of the plurality of compression rings of the axial upper portion 74 may be more than two, for example three compression rings.

[0130] Each of the compression rings 71 , 72 , and 78 extends in the circumferential direction C. As shown in FIG.

[0131] exist Figure 2a and Figure 2b In the embodiment of the present invention, a compression ring 78 of an axially lower portion 75 is arranged in a groove 77 extending circumferentially around the piston skirt.

[0132] It should be noted that all compression rings can generally be positioned in corresponding grooves, e.g. Figure 2a and Figure 2b Thus, the compression rings 71, 72 are arranged in corresponding circumferentially extending grooves.

[0133] In this example, the axially lower portion 75 of the piston 31 also includes an oil control ring 76 disposed axially below the compression ring 78. The oil control ring 76 is configured to distribute oil during the movement of the piston 31 along the cylinder wall 30a. The oil control ring 76 is typically located at the bottom of the piston 31 and closest to the crankcase volume. The oil control ring also serves to scrape any excess oil from the wall of the cylinder liner as the piston 31 moves.

[0134] However, the oil control ring 76 is an optional ring of the piston 31, and other ring arrangements are possible. The oil control ring 76 is also arranged like the other rings and positioned in the corresponding groove. The oil control ring can be a single piece or a multi-piece. In order to increase the contact pressure between the ring and the liner surface, the ring can have a chamfered edge on the outside of the land or facing the combustion chamber to reduce oil consumption by improving oil scraping from the hole.

[0135] It should be noted that any of the compression rings 71, 72, 78 may be defined by a uniform rectangular cross section or a tapered cross section. Figure 2a and Figure 2b In the embodiment, each of the compression rings 71, 72, 78 has a uniform rectangular cross section. In this context, the cross section is defined by the extension in the axial direction A and the extension in the radial direction R.

[0136] The compression rings 71, 72, 78 and the oil control rings can be made of cast iron and are often coated with alloys, which are well known. The most common alloy cast irons are chromium, molybdenum, vanadium, titanium, nickel and copper. The piston ring material should usually be harder than the cylinder liner to extend service life.

[0137] Figure 3 Shows Figure 2a and Figure 2b Another type of compression ring of the piston 31. Figure 3 In one example, at least one compression ring 78 of the axially lower portion is a Napier type compression ring.

[0138] There are at least two designs of Napier-type compression rings. The first has a rectangular cross section with a concave geometry on the bottom outer surface. The second is similar, but with a slightly tapered outer surface. Because the inner surface is undercut, the cross section forms a kind of hook or claw shape. Figure 3 , a Napier-type compression ring 78 having such a recessed geometry 178 is shown.

[0139] Now go to Figure 2c , which shows that Figure 2a to Figure 2b Further details of the ICE system 10 are shown.

[0140] exist Figure 2c middle, Figure 2a to Figure 2b At least one cylinder in is represented as a first cylinder 30. Similarly, Figure 2a and Figure 2b Other features described in Figure 2c In other words, Figure 2a and Figure 2bThe piston in the cylinder is here a reciprocating first piston 31, or simply referred to as the first piston 31, the cylinder wall is here a first cylinder wall 30a, the cylinder head is here a first cylinder head 30b, etc. The above-mentioned arrangement examples of the cylinder 30, the piston 31, the cylinder wall 30a, the cylinder head 30b, and any one of the rings (such as the compression ring 78) are applicable to the first cylinder and its components and any other cylinders described herein, such as the second cylinder, the third cylinder, etc.

[0141] exist Figure 2c In the embodiment of the present invention, the ICE system 10 is a spark ignition ICE system. The ICE system 10 includes a two-stroke ICE 20 that can operate on a gaseous fuel 50 or a liquid fuel 50 .

[0142] In this example, the two-stroke ICE 20 can be operated with a gaseous fuel in the form of a hydrogen-based fuel. The combustion in this hydrogen ICE system 10 is based on the combustion of air and hydrogen, as known in the art. Although the combustion of hydrogen and oxygen may only produce water as its only product in the pure combustion process between hydrogen and oxygen, the hydrogen ICE system 10 based on the combustion of air and hydrogen usually produces water, heat and NOx, as known in the art. In addition, hydrogen can be burned in various fuel-air mixtures in an internal combustion engine. The hydrogen ICE system 10 can be operated to produce very low emissions during certain conditions. The hydrogen ICE system 10 can be operated based on hydrogen liquid or hydrogen. The hydrogen ICE system 10 described herein contributes to the leaner operation of the ICE 20, which is advantageous from the perspective of NOx emissions.

[0143] like Figure 2c as well as FIG. 4A to FIG. 4D As depicted, the ICE 20 includes a first cylinder 30 and a second cylinder 40. The first cylinder 30 includes a first cylinder wall 30a and a first cylinder head 30b. The first cylinder wall may be part of a cylinder liner. Similarly, the second cylinder 40 includes a second cylinder wall 40a and a second cylinder head 40b. The second cylinder wall may be part of a corresponding cylinder liner.

[0144] The first cylinder 30 and the second cylinder 40 here are a pair of first cylinders 30 and second cylinders 40. Typically, although strictly speaking not necessary, the first cylinder 30 and the second cylinder 40 here are a pair of adjacent first cylinders 30 and second cylinders 40. In this article, the term "adjacent" generally means that the cylinders are arranged adjacent to each other, that is, adjacent to each other in the ICE system, so as to allow a pair of cylinders that operate according to two-stroke operation to be formed. In other words, the first cylinder 30 and the second cylinder 40 are arranged adjacent to each other in the ICE20. This may have a positive impact on the volumetric efficiency of the ICE system 10. However, it should be noted that in some ICE systems, the first cylinder and the second cylinder can be arranged to be slightly spaced apart from each other, as long as these cylinders work as a pair of cylinders, that is, these cylinders are connected to the same crankshaft and are separated by a crank angle of 180 degrees, as further described herein.

[0145] It should be noted that the ICE 20 may include any number of cylinders. Specifically, the ICE 20 may include any even number of cylinders. For example, the ICE 20 may include four, six, or eight cylinders. However, for ease of reference, the description herein is directed to an ICE system 10 having a pair of cylinders 30, 40.

[0146] like Figure 2c As shown, the ICE system 10 also includes a crankshaft 27, a set of connecting rods 28, 29, and a crankcase 65. The crankcase 65 is configured to house the crankshaft 27 and the connecting rods 28, 29. Each of the connecting rods 28, 29 is operably connected to a corresponding piston, as further described below.

[0147] In this example, if Figure 2c As shown, the ICE system 10 includes a common crankcase housing 65 for both cylinders 30, 40. Thus, in this example, the common crankcase housing 65 includes a common crankcase volume portion 69 for the pair of cylinders 30, 40.

[0148] The ICE system 10 may also include an oil sump 62 and an oil splash plate 68. These components are conventional parts of an ICE and will not be described further herein.

[0149] The first cylinder 30 is configured to accommodate a reciprocating first piston 31. The reciprocating first piston 31 is operable between a bottom dead center BDC and a top dead center TDC.

[0150] More specifically, if Figure 4A Combination Figure 4D It can be seen that the first piston 31 is arranged in the first cylinder 30 at BDC ( Figure 4D ) and TDC ( Figure 4A ) reciprocates between. Figure 4D, the first piston 31 is at the TDC position at -360°, 0° and 360° CAD. As with a conventional internal combustion engine, the first piston 31 is connected to the crankshaft 27 via a connecting rod 28 .

[0151] The first piston 31 here includes Figure 2a and Figure 2b The piston rings described and shown. For example, the first piston 31 includes compression rings 71, 72, compression ring 78 and oil control ring 76. The number of piston rings and the type of piston rings are selected based on the fuel of the ICE system 10. In this example, the piston rings are arranged at the axial upper portion 74 of the top end 33 of the first piston 31 and at the axial lower portion 75 of the first piston 31, as shown in FIG. Figure 2a and Figure 2b shown.

[0152] The reciprocating first piston 31 also at least partially defines a first combustion chamber 32 with a top end 33 of the first piston 31. The first combustion chamber 32 is arranged at an end of the first cylinder 30 (ie, the cylinder head 30b) such that an upper surface of the top end 33 defines a lower side of the first combustion chamber 32.

[0153] The first cylinder 30 further includes an ignition source 34. The ignition source 34 is arranged in the first combustion chamber 32. The ignition source 34 is arranged in the first cylinder 30 and is located facing the combustion chamber 32. For example, the ignition source 34 is arranged at the upper end of the cylinder 30, as shown in FIG2. Specifically, the ignition source 34 is arranged at the cylinder head 30b of the first cylinder 30. Other arrangements of the ignition source are also conceivable.

[0154] As described herein, the ignition source 34 is configured to ignite hydrogen supplied via a fuel device. For example, the ignition source is a spark plug 17. A spark plug is a device for delivering electrical current from an ignition system to a combustion chamber of a spark-ignition engine to ignite a compressed fuel / air mixture by an electrical spark while maintaining combustion pressure within the engine.

[0155] Furthermore, the first cylinder 30 of the ICE 20 includes at least one intake port 35 which is arranged at a top end 36 of the first cylinder 30 and is in fluid communication with the combustion chamber 32. The top end 36 here is a component of the cylinder head 30b.

[0156] Additionally, the flow of combustible gas through the at least one intake port 35 may be controlled by an intake control valve 37. In this example, the combustible gas typically comprises a mixture of air and port injected hydrogen (gaseous fuel).

[0157] The intake control valve 37 is arranged to open and close a fluid passage of the intake port 35 , thereby controlling the flow of fluid to the combustion chamber 32 .

[0158] Furthermore, the first cylinder 30 of the ICE 20 includes an exhaust port 38 disposed at a position away from the top end 36 of the first cylinder 30 such that when the first piston 31 is at its top dead center, the at least one intake port 35 and the exhaust port 38 are located at different positions and separated by the piston top end 33.

[0159] More specifically, if Figure 2c As shown, the first cylinder 30 includes a first exhaust port 38. The first exhaust port 38 is configured to discharge the combusted gas from the first cylinder 30. The first exhaust port 38 is arranged at a position away from the top end 33 of the first cylinder 30. Therefore, when the first piston 31 is at its TDC, the intake port 35 and the exhaust port 38 are located at different positions and are separated by the top end 33. In this article, the term "away" means that the exhaust port 38 is arranged to be spaced apart from the top end 33 along the direction Z of the cylinder 30, and the direction Z corresponds to the axial direction of the piston 31. Therefore, the top end 33 is considered to be a proximal part of the first cylinder 30. In other words, the first piston 31 is arranged in the first cylinder 30 for reciprocating movement along the central axis ZA1, where the central axis ZA1 extends along the direction Z. In other words, in this example, the axial direction of the piston 31 corresponds to the direction Z. Therefore, the central axis ZA1 is arranged to be parallel to the direction Z. Therefore, the first exhaust port 38 is arranged at a position away from the top end 33 of the first cylinder 30 in the axial direction of the first cylinder 30 and the first piston 31 (corresponding to the direction Z here).

[0160] For example, the exhaust port 38 is arranged at a lower middle portion 39 of the first cylinder 30 .

[0161] In some examples, such as Figure 2c As shown, when the first cylinder 30 includes a first cylinder liner, the cylinder liner here also includes an exhaust port 38 located at a lower middle portion 39 of the cylinder liner. Therefore, the exhaust port 38 is generally arranged at a position away from the top end 33 of the first cylinder 30 and is located in the cylinder wall 30a of the cylinder liner of the first cylinder 30.

[0162] The second cylinder 40 is configured to accommodate a reciprocating second piston 41. The reciprocating second piston 41 is operable between a bottom dead center BDC and a top dead center TDC.

[0163] More specifically, if Figure 4A Combination Figure 4D It can be seen that the second piston 41 is arranged in the second cylinder 40 at BDC ( Figure 4A ) and TDC ( Figure 4A ) reciprocates between. Figure 4A , the second piston 41 is at the TDC position at -360°, 0° and 360° CAD. As with a conventional internal combustion engine, the second piston 41 is connected to the crankshaft 27 via a connecting rod 29.

[0164] The second piston 41 here includes Figure 2a and Figure 2b A set of piston rings is described and shown. For example, the second piston 41 includes corresponding compression rings 71, 72, corresponding compression ring 78 and corresponding oil control ring 76. The number of piston rings and the type of piston rings are selected based on the fuel of the ICE system 10. In this example, the piston rings are arranged at the axial upper portion 74 of the top end 33 of the second piston 41 and at the axial lower portion 75 of the second piston 41, as shown in FIG. Figure 2a and Figure 2b shown.

[0165] The reciprocating second piston 41 also at least partially defines a second combustion chamber 42 with a top end 43 of the second piston 41. The combustion chamber 42 is arranged at the end of the second cylinder 40 (ie, the second cylinder head 40b) so that an upper surface of the top end 43 defines a lower side of the second combustion chamber 42.

[0166] Each of the piston tips may have a flat top or the piston tips may be slightly concave to avoid hot spots.

[0167] The second cylinder 40 also includes a corresponding ignition source 44 arranged in the second combustion chamber 42. The ignition source 44 is arranged in the second cylinder 40 and is located facing the combustion chamber 42. For example, the ignition source 44 is arranged at the upper end of the combustion cylinder 40, as shown in Figure 2. Specifically, the ignition source 44 is arranged at the cylinder head 40b of the second cylinder 40. Other arrangements of the ignition source are also conceivable.

[0168] Each of the ignition sources 34, 44 is a spark plug in this case. The ignition source may also be a glow plug.

[0169] Therefore, in each cylinder, there is a corresponding spark plug arranged to ignite the fuel and oxygen mixture in the cylinder. The hydrogen fuel is usually compressed to a certain level. The spark plug thereby ignites the compressed air-fuel mixture.

[0170] Furthermore, the second cylinder 40 of the ICE 20 comprises at least one corresponding intake port 45, which is arranged at a top end 46 of the second cylinder 40 and is in fluid communication with the second combustion chamber 42. The top end 46 here is an integral part of the cylinder head 40b.

[0171] Additionally, the flow of combustible gas through at least one corresponding intake port 45 may be controlled by a corresponding intake control valve 47. In this example, the combustible gas typically comprises a mixture of air and port injected hydrogen (gaseous fuel).

[0172] The intake control valve 47 is arranged to open and close a fluid passage of the intake port 45 , thereby controlling the flow of fluid to the combustion chamber 42 .

[0173] In addition, the second cylinder 40 of the ICE 20 includes a corresponding exhaust port 48, which is arranged at a position away from the top end 46 of the second cylinder 40, so that when the corresponding second piston 41 is at its top dead center, at least one corresponding intake port 45 and the corresponding exhaust port 48 are located at different positions and separated by the piston top end 43.

[0174] Similar to the first cylinder and its exhaust port, the corresponding exhaust port 48 is configured to discharge the combusted gas from the second cylinder 40. The corresponding exhaust port 48 is arranged at a position away from the top end 43 of the second cylinder 40. Therefore, when the second piston 41 is at its TDC, the intake port 45 and the exhaust port 48 are located at different positions and are separated by the top end 43. In this context, the term "distant" means that the exhaust port 48 is arranged to be spaced apart from the top end 43 along the direction Z of the second cylinder 40, which corresponds to the axial direction of the second piston 41. Therefore, the top end 43 is considered to be a proximal portion of the second cylinder 40.

[0175] More specifically, the second piston 41 is arranged in the second cylinder 40 for reciprocating movement along the center axis ZA2, which here extends in the Z direction. In other words, in this example, the axial direction of the second piston 41 corresponds to the direction Z. Therefore, the center axis ZA2 is arranged to be parallel to the direction Z. Therefore, the second exhaust port 48 is arranged at a position away from the top end 43 of the second cylinder 40 in the axial direction of the second cylinder 40 and the second piston 41 (which here corresponds to the direction Z).

[0176] For example, the exhaust port 48 is arranged at a lower middle portion 49 of the second cylinder 40. The exhaust port 48 is arranged at a lower middle portion 49 of the second cylinder 40 as viewed along the center axis ZA2.

[0177] It should be noted that in Figure 2c , the first center axis ZA1 of the first piston 31 is arranged parallel to the second center axis ZA2 of the second piston 41. However, the pistons may also be arranged in a slightly different configuration, wherein the first center axis ZA1 of the first piston 31 is arranged non-parallel to the second center axis ZA2 of the second piston 41, at least as long as the first cylinder and the second cylinder are arranged 180 degrees apart from each other by a crank angle.

[0178] In some examples, such as Figure 2cAs shown, when the second cylinder 40 includes a second cylinder liner, the cylinder liner includes a corresponding exhaust port 48 located at the lower middle portion 49 of the cylinder liner. Therefore, the corresponding exhaust port 48 is generally arranged at a position away from the top end 43 of the second cylinder 40 and is located in the cylinder wall 40a of the cylinder liner of the second cylinder 40.

[0179] like Figure 2c As shown, a pair of adjacent first cylinders 30 and second cylinders 40 are arranged to be separated from each other by 180 degrees (180 CAD) of crank angle. In this way, the cylinders 20, 30 are separated from each other to provide a 180 degree combustion phasing separation. Therefore, the cylinders 30, 40 can be arranged in the ICE system 10 to provide a 180 degree cycle separation regardless of the ICE and cylinder arrangement / configuration.

[0180] By arranging the exhaust ports 38, 48 in the lower middle portion of the cylinders 30, 40, when the corresponding piston is at its TDC, the corresponding intake ports 35, 45 and the exhaust ports 38, 48 are located at different positions in each cylinder 30, 40 and are separated by the corresponding piston top 33, 43. Therefore, by arranging the corresponding intake ports 35, 45 and the exhaust ports 38, 48 of the cylinders 30, 40 at different positions along the direction Z (i.e., along the axial direction of the piston and the cylinder), when the corresponding piston is at its TDC, the corresponding piston will provide a blocking effect between the intake port and the exhaust port, so that the hot part of the cylinder (exhaust port and cylinder wall / liner) will be completely separated from the combustible gas (air). Figure 2c as well as Figure 4A and 4D The blocking effect is at least schematically shown.

[0181] Thus, the configuration of the intake and exhaust ports enables the length-scavenging ICE system to separate the hot exhaust end of each cylinder from the cold intake end where combustibles are present. As a result, the risk of knock during operation of the ICE system 10 can be reduced. Compared to a two-stroke diesel ICE using multiple cylinders, this also allows the corresponding combustion chambers to be reversely scavenged via a controllable intake valve in the cylinder head and an exhaust port at the cylinder wall / liner (e.g., in the lower portion of the cylinder wall). In other words, compared to more conventional ICE systems, there are no exhaust valves in the cylinder head.

[0182] Through the combination of the arrangement of the ignition sources 34, 44 and the locations of the intake and exhaust ports 35, 45, 38, 48, the ICE system 10 is configured to provide forced induction in the top of the cylinder, provide an ignition source for igniting the fuel in each combustion chamber 32, 42, and is also configured to discharge exhaust gas through the corresponding exhaust ports 28, 38 in the lower middle portion of the corresponding cylinder (e.g., the lower portion of the wall 30a, 40a of the cylinder liner).

[0183] In addition, if Figure 2c As depicted, the ICE system 10 includes an intake conduit 22. The intake conduit 22 is a manifold that is arranged and configured to supply intake air to cylinders, in this example a first cylinder 30 and a second cylinder 40.

[0184] The intake duct 22 includes a positive displacement device 23, such as Figure 2c As shown. The positive displacement device 23 is configured to receive the intake air 51 and supply it to at least one pair of adjacent cylinders 30, 40. The intake duct 22 includes an intake passage 24 and a plenum 25. The intake passage 24 is arranged upstream of the positive displacement device 23. The plenum 25 is arranged downstream of the positive displacement device 23. The positive displacement device 23 is also arranged in the intake duct 22 to separate the upstream intake passage 24 of the intake duct 22 from the downstream plenum 25.

[0185] It should be noted that in some examples, the plenum 25 may be an integral part of the cylinder head of the cylinder. Thus, at least part of the intake duct may be an integral part of the cylinder head of the cylinder.

[0186] The positive displacement device 23 is configured to be fluid-tight to prevent backflow from the combustion chambers 32, 42. Furthermore, the positive displacement device 23 is configured to exhaust its (complete) internal displacement per revolution.

[0187] The positive displacement device 23 here is a positive displacement pump. The positive displacement pump is configured to displace gas from an upstream position to a downstream position of the intake duct 22 by capturing a fixed amount of air and pushing the captured amount of air from an upstream position to a downstream position.

[0188] By way of example, the positive displacement device 23 is a rotary Roots-type blower having a pair of rotating members 23a, 23b provided with engaging lobes.Other configurations of the positive displacement device are also readily understood.

[0189] The positive displacement device 23 here is a variable positive displacement device configured to operate in a variable manner. The use of a variable drive positive displacement device allows the intake duct forming the intake system of the ICE system 10 to have greater flexibility. The use of a variable drive positive displacement device also helps to improve the overall functionality of the ICE system 10. Positive displacement devices generally operate with flow and pressure as independent variables. This means that if the pressure increases while the velocity remains constant, the flow rate is substantially unaffected. A variable positive displacement device (such as a pump) is a device that converts mechanical energy into hydraulic (fluid) energy. The displacement can vary when the pump is running. The positive displacement device can be driven variably to achieve a high degree of flexibility and improved functionality of the ICE system.

[0190] The positive displacement device 23 may be electrically driven, hydraulically driven, etc. An electric positive displacement device may also improve turbocharger transients by boosting scavenged air, which may also drive the turbine in the turbocharger. This configuration of an ICE system may allow for pressure reduction before the displacement pump and / or after the turbocharger compressor, thereby immediately reducing the workload of the compressor.

[0191] The upstream air intake passage 24 is here a component of the air intake duct 22. The air intake duct 24 is provided, for example, in the form of a cylindrical housing with an inner volume. A plenum 25 is usually also a component of the air intake duct 22.

[0192] In addition, if Figure 2c As shown, the downstream plenum 25 is in fluid communication with each of the first cylinder 30 and the second cylinder 40. For example, Figure 2c As shown, the downstream plenum 25 is in fluid communication with each of the first cylinder 30 and the second cylinder 40 via respective intake ports 35 , 45 .

[0193] exist Figure 2c In the embodiment, the downstream plenum 25 is provided in the form of a so-called Siamese design. This Siamese design has a first inlet duct 25a and a set of two outlet ducts 25b, 25c, such as Figure 2c The diameter and length of the inlet and outlet conduits may vary depending on the type of ICE system 10, and Figure 2c The air chamber 25 in FIG. 2 is only shown schematically.

[0194] The plenum 25 includes an air inlet 25d in fluid communication with the positive displacement device 23 and a plurality of outlets 25e, 25f configured to be in fluid communication with the intake ports 35, 45 of the first and second cylinders 30, 40, respectively. The first inlet conduit 25a has an air inlet, and the outlet conduits 25b, 25c have corresponding outlets.

[0195] Thus, the plenum 25 is defined by the conduit arrangement between the intake ports 35, 45 of the first and second cylinders 30, 40 and the positive displacement device 23, such as for example Figure 2c Depicted.

[0196] The plenum 25 may also be provided in other ways, such as by a single large internal volume defined by a common conduit. The internal volume of the plenum should generally be selected to provide effective flashback protection, and therefore minimizing the internal volume of the plenum may be beneficial in view of the other volumes of other components.

[0197] The arrangement and configuration of the plenum 25 in combination with the positive displacement device 23 provides an improved air supply system for supplying air to the cylinders 30 , 40 .

[0198] It should be noted that even though the positive displacement device 23 provides a substantially fluid-tight seal in the intake conduit 22, due to the configuration of the cylinders 30, 40 being separated by 180 CAD, air will continue to flow through the positive displacement device 23 as the pair of cylinders 30, 40 interact with respect to intake events.

[0199] By arranging the positive displacement device 23 in the intake duct 22 , the positive displacement device 25 is arranged to eliminate or at least reduce the risk of pressure pulses being transmitted from the combustion chambers 30 , 40 back to the upstream intake port 24 of the intake duct 22 .

[0200] The intake ports 35, 45 are thus mechanically isolated from the intake duct 24. The positive displacement device 23 is thus arranged to seal the cylinders 30, 40 and the downstream plenum 25 from the upstream intake duct 24 of the intake duct 22 (intake manifold) in the event of a flashback. This arrangement of the ICE system thus allows a better control of the risk of flashback, i.e. a situation in which a flame escapes from the combustion chamber of a cylinder and enters upstream into the intake duct.

[0201] Furthermore, through the arrangement and configuration of the positive displacement device 23 in the intake conduit 22 , the positive displacement device 23 can still provide uniform flow by alternately supplying the cylinder pairs 30 , 40 .

[0202] Furthermore, in some examples, such as regarding Figure 3 As described, a general ICE system 10 is used to suppress the knock and / or autoignition tendency of a fuel, such as a gaseous fuel, for example a hydrogen-based fuel. This is achieved, for example, by a combination of having a separate intake plenum 23 for each pair of cylinders 30, 40 having a 180 degree combustion orientation separation, and wherein for each pair of cylinders 30, 40, the intake conduit 22 has a close coupled positive displacement device 23. By arranging the positive displacement device 25 close to the cylinder, the internal volume of the plenum 25 can be minimized, thereby providing more effective flashback protection.

[0203] The ICE system 10 herein includes a fuel injector assembly 26 such as Figure 2c A fuel injector device 26 is arranged in the plenum 25 of the intake duct 22 to provide fuel injection upstream of the intake ports 35, 45 of the cylinders 30, 40. In this way, improved fuel injection into the combustion chambers 32, 42 of the ICE 20 is provided.

[0204] The fuel injector assembly 26 includes at least one fuel injector configured to inject fuel. Figure 2cIn the embodiment of the present invention, the fuel injector device 26 includes a set of two fuel injectors 26a, 26b. Typically, one fuel injector 26a, 26b is arranged upstream of the respective intake port 35, 45. For example, the outlet conduit 25b includes the first fuel injector 26a, and the outlet conduit 25c includes the second fuel injector 26b. Thus, the ICE system 10 is configured to provide port injection of the gaseous fuel 50 upstream of the respective intake port 35, 45. The use of port injection allows a homogeneous mixture to be provided, thereby improving knock and auto-ignition control and helping to reduce emissions.

[0205] The fuel injector device 26 can be controlled / operated in response to a fuel injection event so that fuel is injected into one or more of the corresponding intake ports 35, 45, thereby generating a pressure pulse in the plenum 25, and the pressure pulse subsequently enters the corresponding combustion chamber 32, 42. Thus, an improved scavenging effect is provided. Therefore, the ICE system 10 is configured to provide a scavenging effect through the injection timing of the corresponding intake ports 35, 45.

[0206] For example, the fuel injector arrangement 26 may be controlled / operated to provide sequential fuel injection to the cylinders 30, 40 so as to allow active cylinder scavenging during the second half of the respective intake stroke of the respective ones of the cylinders 30, 40. The fuel injector arrangement is here controlled by a control unit.

[0207] In other words, sequential injection enables active cylinder scavenging (emptying the exhaust) during the second half of the intake stroke and creates a final pressure pulse (from the injected fuel) that increases the trapped mass in the cylinder after any exhaust and intake valves close. This can also result in the plenum and / or intake ports being empty of fuel after the intake valve closes.

[0208] Furthermore, the pressure pulses generated enhance the scavenging effect.

[0209] It should be noted that sequential injection can be adjusted for different speeds and valve timings.

[0210] Generally speaking, the pressure pulse will also travel backwards into the downstream chamber 25. For example, the pressure pulse will be reflected in the closed sister cylinder intake valve. Thereafter, the pressure pulse returns to the still open intake valve and enters the cylinder through the open valve and completes the cylinder filling, thereby also helping to completely capture the mass.

[0211] In some examples, although not shown, a fuel injector 26 a , 26 b of the fuel injector arrangement 26 may be arranged in each of the combustion chambers of the cylinders.

[0212] Turning again to the intake ports 35 , 45 and the intake valves 37 , 47 , the ICE system 10 in FIG. 2 is here provided with two intake valves 37 for the first cylinder 30 and two intake control valves 47 for the second cylinder 40 .

[0213] Therefore, in some examples, each of the cylinder heads 30b, 40b includes at least two intake control valves. In some examples, each of the cylinder heads 30b, 40b of the first cylinder 30 and the second cylinder 40 may have multiple intake control valves. For example, each of the cylinder heads may have four intake control valves. This configuration provides a more improved air supply system for supplying air to each of the cylinders. The configuration of the ICE system with four intake control valves per cylinder is particularly beneficial for a two-stroke ICE system operating with a hydrogen-based fuel because its intake cycle is shorter than that of a four-stroke ICE system. In addition, the configuration of the ICE system with four intake control valves per cylinder allows an increase in the intake rate of the combustion chambers 32, 42 of the cylinders 30, 40, thereby also improving the volumetric efficiency. For this reason, at least compared to conventional ICE systems (such as four-stroke ICE systems), the ICE system 10 including the arrangement of the positive displacement device 23 combined with the arrangement of four intake valves in each cylinder can achieve even higher volumetric efficiency.

[0214] exist Figure 2c In some examples, the intake control valves 37, 47 are configured to provide variable valve actuation. Variable valve actuation may be provided by a hydraulic system, an electronic system, or a pneumatic system. However, the intake control valves 37, 47 may also be conventional intake control valves, such as camshaft-based systems commonly used in diesel ICE systems. Thus, in some examples, the intake control valves are conventional camshaft-actuated valves. Depending on the arrangement and configuration of the valves, such camshaft-actuated valves may also include variable valve actuation.

[0215] exist Figure 2c In the embodiment, the ICE system 10 includes an intake control valve actuation assembly 63 for actuating at least one intake control valve 37 and a corresponding intake control valve 47. The intake valve actuation assembly 63 is adapted to actuate the intake control valves 37, 47 according to one or more lift modes during a combustion cycle of the ICE system, which will also be described with respect to FIG. FIG. 4A to FIG. 4D Further description.

[0216] As from Figure 2c It can also be seen that each of the exhaust ports 38 , 48 is arranged in fluid communication with an exhaust conduit 61 arranged to convey exhaust gas away from each of the cylinders.

[0217] In addition, if Figure 2cAs shown, the ICE system 10 here includes a turbocharger device 170. The turbocharger device 170 includes a turbocharger turbine 171 operatively connected to a turbocharger compressor 172, wherein the turbocharger compressor 172 is arranged in an intake duct 173 in fluid communication with the intake duct 22. The turbocharger turbine 171 is arranged in the exhaust duct 61 so as to drive the turbocharger compressor 172. In other words, the turbine 171 is configured to convert engine exhaust gas into mechanical energy to drive the compressor 172.

[0218] The turbocharger turbine 171 may be a conventional turbine for use with the ICE system 10. Alternatively, the turbocharger turbine 171 may be a variable geometry turbine in fluid communication with the cylinders.

[0219] exist Figure 2c , the ICE system 10 further comprises an exhaust gas recirculation (EGR) system 80 comprising an EGR conduit 81 arranged to connect the exhaust conduit 61 and the intake conduit 22 so as to allow exhaust gas to be recirculated through the cylinders during operation of the ICE.

[0220] The EGR system 80 here also includes a corresponding positive displacement device 82. The positive displacement device 82 is arranged in the EGR duct 81. The positive displacement device 82 is generally of the same type as the device 23, but can also be provided in other ways. For example, the positive displacement device 82 is a Roots blower.

[0221] The EGR conduit 81 connects to the intake conduit 73 at a location 84 downstream of the turbocharger compressor 172 and further connects to the exhaust conduit 61 at a location 85 upstream of the turbocharger turbine 171 .

[0222] Usually, if Figure 2c As shown, the ICE system 10 may also include an air cooler 67, such as a charge air cooler (CAC). For example, the CAC 67 is arranged in the intake duct 173. More specifically, as seen in the flow direction from the compressor 172 to the intake duct 22, the CAC 67 is arranged in the intake duct 173 between the turbocharger compressor 172 and the intake duct 172.

[0223] It should be easy to understand that Figure 2c The intake duct may have its own inlet for receiving fresh air from the outside and / or be configured to receive air from the intake conduit 73 .

[0224] For Figure 2c In the illustrated ICE system 10 with a turbocharger 170, the positive displacement device 23 may cooperate with the upstream mounted turbocharger in a number of ways:

[0225] If the intake air flow is at the desired level, the positive displacement device 23 simply rotates to move the air volume through the rotor. In this case, the positive displacement device consumes little energy because no compression occurs. Then, the blocking part of the intake duct 22 and the upstream intake duct 24 also plays a role (depending on the design).

[0226] If in a transient state and the turbocharger has not yet spun up, the positive displacement device 23 can spin faster and support increased boost pressure, thereby increasing the response of the ICE 20. Transient operation is often challenging for H2 ICE systems 10 with traditional boost settings because transients often result in a reduced air / fuel ratio, which in turn results in knock tendencies or NOx production. By controlling the air during the transient with additional boost, this problem can be eliminated or at least reduced to a large extent.

[0227] At certain operating points, when the turbocharger is insufficient to provide boost, the positive displacement device 23 may be supported with additional boost to improve control of air / fuel ratio, cylinder scavenging, etc. (ie, combustion control).

[0228] In addition, regarding Figures 2a to 2c In the depicted ICE system 10 , the ICE system 10 also includes a controller 90 configured to collectively control the positive displacement device 23 and the intake valves 37 , 47 to control the flow of gas to the respective combustion chambers 32 , 42 .

[0229] For example, controller 90 is configured to terminate fuel injection during the intake phase and prior to intake valve closing such that the remainder of the intake phase includes purging plenum 25 of fuel and then introducing fresh air into plenum 25 by operating positive displacement device 23 .

[0230] The following is an example of a sequence for operating the ICE system 10 during two-stroke operation. FIG. 4A to FIG. 4D Describe the sequence of two-stroke operation.

[0231] In general, it should be noted that each of the first cylinder 30 and the second cylinder 40 has three main events. These events are compression events, combustion and power events, and exhaust and intake events. When the corresponding piston travels from BDC to TDC, when the corresponding piston is in the upper half of the corresponding cylinder, the compression event occurs. When the corresponding piston travels from TDC to BDC, when the corresponding piston is in the upper half of the corresponding cylinder, the combustion and power events occur. Exhaust and intake events usually occur when the corresponding piston is in the lower half of the corresponding cylinder. For example, when the corresponding piston is in the lower half of the cylinder and travels toward its BDC, passes through its BDC and / or when the corresponding piston is in the lower half of the cylinder and moves toward its TDC, exhaust and intake events occur.

[0232] However, it should be noted that the exhaust and intake events may occur in different areas of the cylinder and can be slightly separated, but the exhaust and intake events will generally occur simultaneously. During the exhaust and intake periods, the ICE system provides a scavenging effect, where fresh intake air pushes residual exhaust gas out of the exhaust port.

[0233] In view of the above, the piston 31, 41 of one of the cylinders 30, 40 may typically perform a compression phase (or event) during about 270-0 CAD, followed by a combustion and power phase (event) during 0-90 CAD in the upper half of the corresponding cylinder as the piston travels from TDC to BDC, while the other piston of the other cylinder performs an exhaust and intake phase (event) in the lower half of the other cylinder during 90 to 270 CAD. It should also be noted that there is typically an overlap between the end of the combustion and power phase (event) and the beginning of the exhaust and intake phase (event).

[0234] More specifically, if FIG. 4A to FIG. 4D As schematically shown, the intake control valve 37 of the first cylinder 30 may be controlled / operated in association with the movement of the first piston 31, and the intake control valve 47 of the second cylinder 40 may be controlled / operated in association with the movement of the second piston 41. In this way, fluid communication between the respective combustion chambers 32, 42 and the plenum 25 is selectively opened and closed during crankshaft rotation of the ICE 20. As described herein, this configuration of the ICE system 10 in combination with the positive displacement device 23 in the intake duct 22 allows for a reduced risk of flashback.

[0235] The intake control valve 37 and the corresponding intake control valve 47 are controlled and actuated by an intake control valve actuation assembly 63. Purely by way of example, the intake control valve actuation assembly 63 may include an electric actuator (not shown) adapted to actuate the intake control valve in at least two lift modes (i.e., between an open mode and a closed mode). The control valve may alternatively or additionally be controlled by a control unit.

[0236] Furthermore, as described above, the cylinders 30, 40 are separated from each other by 180 degrees of crank angle. This arrangement and configuration of the ICE system 10 allows for 180 degrees of combustion phasing separation. The effect of the control of the intake valves over the intake ports combined with the 180 degrees of combustion phasing separation can be achieved by Figure 4A and 4D The diagram in is an example: exist Figure 4A In the embodiment, when the corresponding intake port 45 of the second cylinder 40 is opened by the intake control valve 47 to provide fluid communication between the second combustion chamber 42 and the plenum chamber 25, the first intake port 35 of the first cylinder 30 is closed by the intake control valve 37 to close the fluid communication between the first combustion chamber 32 and the plenum chamber 25. Figure 4A In the embodiment, the first piston 31 is at its TDC. In this position, the ignition event of the first cylinder 30 is about to start, or has just started. The intake control valve 37 is thus closed. In addition, in Figure 4A In the figure, the second piston 41 is at its BDC and the corresponding intake control valve 47 of the second cylinder 40 is fully open. The second cylinder 40 and the second piston 41 are shown here in positions corresponding to exhaust and intake events, that is, fresh intake air from the intake port 45 enters the second cylinder 40 and pushes residual exhaust gas out of the exhaust port 48. Since the cylinders 30, 40 are separated by 180 degrees of crank angle (also provided here with 180 degrees of combustion phasing separation), the first piston 31 and the second piston 41 can perform such simultaneous operation.

[0237] Then, if Figure 4B As shown, the first cylinder 30 and the first piston 31 perform the combustion and power generation phases, wherein the first piston 31 travels from its TDC to its BDC. In this position, the intake control valve 37 is closed. In addition, as shown in FIG. Figure 4B As shown, the second piston 41 in the second cylinder 40 travels from its BDC to its TDC while performing its intake phase to receive fresh air from the corresponding intake port 45. In this position, the corresponding intake control valve 47 is partially open, as shown in FIG. Figure 4B Since the cylinders 30, 40 are separated by 180 degrees of crank angle (also providing 180 degrees of combustion phasing separation here), the first piston 31 and the second piston 41 can perform such simultaneous operation.

[0238] exist Figure 4C In FIG. 1 , the first cylinder 30 and the first piston 31 are shown at the end of the combustion and power generation phase, wherein the first piston 31 is close to its BDC. In this position, the intake control valve 37 is controlled to move from its closed position to an open position. Figure 4C In FIG. 1 , the intake control valve 37 is shown in a partially open position. Figure 4CAs shown, the second piston 41 is close to its TDC, and the corresponding intake control valve 47 is set to its closed position. In this position, the second cylinder 40 and the second piston 41 perform a compression phase to compress the received fresh air. Since the cylinders 30, 40 are separated by 180 degrees of crank angle (also provided here with 180 degrees of combustion phasing separation), the first piston 31 and the second piston 41 can perform such simultaneous operation.

[0239] Finally, if Figure 4D As shown, the first piston 31 is at its BDC and the corresponding intake control valve 37 of the first cylinder 30 is fully open. The first cylinder 30 and the first piston 31 are here in a position corresponding to the exhaust and intake events, that is, the fresh intake air from the intake port 35 enters the first cylinder 30 and pushes the residual exhaust gas out of the exhaust port 38. In addition, the second piston 41 is at its TDC. At this position, the ignition event of the second cylinder 40 is about to start, or has just started. The corresponding intake control valve 47 is therefore closed. Since the cylinders 30, 40 are separated by 180 degrees of crank angle (here also 180 degrees of combustion phasing separation is provided), the first piston 31 and the second piston 41 can perform such simultaneous operation.

[0240] As from Figure 4D It can also be seen that when the corresponding intake port 45 of the second cylinder 40 is closed by the intake control valve 47 to close the fluid connection between the second combustion chamber 42 and the accumulator chamber 25, the intake control valve 37 at the first intake port 35 of the first cylinder 30 is opened to provide fluid connection between the first combustion chamber 32 and the accumulator chamber 25.

[0241] In addition, if FIG. 4A to FIG. 4D It can be seen that since the first cylinder 30 and the second cylinder 40 are arranged to be 180 degrees apart from each other in crank angle, the ICE system 10 is configured to operate the intake valves 37, 47 of the first cylinder 30 and the second cylinder 40 so that when the corresponding piston moves up halfway in the cylinder, the intake valves 37, 47 of the cylinders 30, 40 are completely closed, which can further reduce the risk of backfire.

[0242] Therefore, by configuring the first cylinder 30 and the second cylinder 40 to be spaced 180 degrees crank angle apart from each other and combining the arrangement of the positive displacement device 23, as shown in FIG. FIG. 4A to FIG. 4D As shown, the risk of flashback can be reduced.

[0243] In addition, despite FIG. 4A to FIG. 4DIt is not explicitly shown in the diagram, but it should be readily understood that upon injection, after scavenging begins, the injected hydrogen fuel will expand and generate a pulse in the intake port and plenum. This pulse will propagate and enhance the scavenging effect and also increase the pressure in the cylinder. However, the pulse is limited from traveling backwards in the intake duct (intake system) by the positive displacement device 23, which acts as a check valve and also momentarily increases the boost pressure during the pulse.

[0244] Furthermore, depending on the closing time of the intake valves 37, 47, the ICE system 10 is operable to cause the combustible gases to expand in the combustion chambers 30, 40 for a period longer than the duration of the compression phase. In this way, a built-in Miller or Atkinson cycle function is provided that improves efficiency.

[0245] Furthermore, because the two-stroke cycle of the ICE system 10 provides twice as many work cycles per revolution as a conventional four-stroke ICE, the ICE system 10 allows operation in lean conditions where it would not be possible to obtain as much work per work cycle as a conventional diesel ICE. That is, the two-stroke cycle can produce twice as many work cycles at the same ICE speed despite the need to run hydrogen and other gases lean for emissions purposes (NOx control).

[0246] In operation of the ICE system 10, the ICE system 10 may perform the following methods: In step S10, when the piston travels downward from TDC to BDC in one of the cylinders during the expansion of the combustibles and the corresponding exhaust port is opened, the effective power stroke ends and the gas is discharged through the exhaust port. Subsequently, in step S20, the intake valve of one of the cylinders is opened and the cylinder is flushed with intake air supplied by the aforementioned supercharging system (e.g., by the turbocharger device 70 and the positive displacement device 23). At this stage, there is no fuel in the supercharged mass or cylinder.

[0247] Then, in step S30, the piston reaches BDC. Subsequently, in step S40, the piston begins to move upward toward its TDC, and the piston eventually covers the exhaust port again. In this position, the fuel injector device operates to inject, for example, hydrogen fuel. The hydrogen fuel is injected into the intake port, thereby generating a pressure pulse of the injected hydrogen fuel. Therefore, the ICE system 10 operates to start injecting hydrogen into the air flow in the plenum 25, thereby supplying air and hydrogen into the cylinder. The injection starts after the intake valve opens just after the initial scavenging (cylinder cleaning) and ends before the intake valve closes, which provides an intake passage that is substantially free of combustible gas.

[0248] The initial scavenging (purge) of the cylinder is the time between IVO and the start of hydrogen injection.

[0249] In step S50 , the piston continues to travel upward in the stroke (approximately halfway) and the intake valve closes.

[0250] In step S60 , the piston travels to just before TDC, TDC, or just after TDC (ie, close to TDC).

[0251] Subsequently, in step S70 , an ignition source (eg, a spark plug) ignites the uniform air / hydrogen mixture in the cylinder.

[0252] Then, in step S80, the piston is forced downward in a power stroke (expansion).

[0253] Thereafter, in step S90, the above steps S10 to S80 are looped and repeated.

[0254] As can be readily appreciated from the above, the flushing, scavenging and subsequent fuel injection operations create a boost pulse, and a hydrogen (H2) / air mixture is pushed into the cylinder at the end of fuel injection, which allows the plenum chamber 25 to be emptied, while the positive displacement device 23 is operated to push fresh air into the plenum chamber 25. In this way, the arrangement and configuration of the ICE system 10 avoids or at least reduces the risk of a hydrogen mixture being present in the plenum chamber 25, thereby reducing the risk of flashback.

[0255] It should be noted that if the intake valves are all opened at the same time, a flow effect can be obtained over the entire cross-sectional area of ​​the cylinder, so that the cylinder is filled evenly from top to bottom, thus discharging the exhaust gas, thus achieving a low mixture between the fresh charge air and the hot exhaust gas combustibles. This may help to reduce the temperature of the mixture and the residues in the mixture preparation process. Then when the piston is halfway up in the cylinder, the intake valve is completely closed, thus reducing the risk of flashback.

[0256] It should be noted that the above description of the ICE system 10 should also be considered to disclose a method for controlling the ICE system 10 , for example using the control system 90 .

[0257] The combustion chamber can be of a number of different designs and can be any of a flat, hemispherical or mono-pitched roof design with only the intake valves. Covering a large area of ​​the combustion chamber with the valves can be beneficial so that cylinder filling can be done in an efficient manner.

[0258] All moving parts in the ICE 20 can generally be lubricated using conventional pressure lubrication. Other options are also possible.

[0259] The positive displacement device 23 and plenum 25 of the intake duct 22 are generally considered cold parts and can be made of aluminum alloy. The intake duct 22 can usually be fastened to the hotter cylinder head, which is made of cast iron or steel. This can minimize the risk of hydrogen embrittlement because no hydrogen-containing gas comes into contact with any iron or steel at a temperature below 150 degrees Celsius, which is the threshold for hydrogen embrittlement.

[0260] The ICE system 10 can be cooled in a variety of different ways. For example, the ICE system 10 includes a controlled low-temperature coolant loop for controlling the temperature of the CAC (compressed air cooler) and / or the EGR cooler. This is used to control the condensation level of water returned from the combustible (H2 produces H2O when H2 is burned). In addition, the ICE system 10 may include a water injection system. The water injection system may be arranged and configured to inject water into the intake port, directly into the cylinder, or before the intake positive displacement device 23. In addition, condensed water in the exhaust gas can be used for water injection. If injected before the positive displacement device, there are benefits of mixing and evaporation / cooling in the Roots blower. After the positive displacement device, water injection is used as a cooling medium for the charge air, which is an advantage in examples where the positive displacement device is used to perform compression work for additional boost.

[0261] It should be noted that the ICE system 10 may not be limited to systems having a pair of cylinders 30 , 40 , but may also be implemented in ICE systems including four cylinders, six cylinders, etc. Thus, the ICE system 10 may have at least two cylinders, but multiples of two cylinders are also possible.

[0262] In ICE systems 10 that further include additional pairs of adjacent cylinders, each arrangement of a pair of adjacent cylinders has a corresponding intake duct with a corresponding positive displacement device.

[0263] In other words, a four cylinder ICE will have two positive displacement devices, and a six cylinder ICE will have three positive displacement devices. Such ICE systems may also use a positive displacement device with multiple separate sections, where each section is provided to cooperate with a given pair of cylinders. In this arrangement, the fluid (air) flowing to each pair of cylinders should be separate from each other. The cylinder pairs can be spaced apart so that the fuel of three cylinders is ignited simultaneously (flat crank), or evenly offset from each other to achieve an evenly distributed firing order. In this way, one cylinder in a pair of cylinders can be charged at the same time without unnecessary pulsation due to one cylinder being on the intake stroke while the other cylinder is on the power stroke.

[0264] Furthermore, the present disclosure may be illustrated by any of the following examples.

[0265] Example 1: An ICE system comprises a two-stroke ICE operated with fuel, the ICE having at least one cylinder with a cylinder wall, and also having a reciprocating piston movable in the cylinder between a bottom dead center BDC and a top dead center TDC in an axial direction, the piston having a piston skirt 70 extending in the axial direction. In addition, the piston comprises an axial upper portion 74 having a top end 33, the top end being intended to form a part of a combustion chamber. In addition, the piston comprises an axial lower portion 75. The at least one cylinder and the top end of the piston at least partially define the combustion chamber 32. The at least one cylinder includes at least one intake port 35 arranged at the top end 36 of the at least one cylinder and connected to the combustion chamber fluid, and also includes an exhaust port 38, which is axially arranged at a position away from the top end of the at least one cylinder, thereby allowing the at least one intake port and the exhaust port to be separated by the piston fluid, and wherein the axially upper portion 74 of the piston includes a plurality of compression rings 71, 72 for sealing at the combustion chamber, and the axially lower portion 75 includes at least one compression ring 78, which is configured to seal along an area 73 of the cylinder wall axially below the exhaust port so as to reduce leakage of blowby gases from the combustion chamber into the crankcase volume portion of the ICE.

[0266] Example 2: The ICE system according to Example 1, wherein the at least one compression ring 78 of the axially lower portion and a compression ring of the plurality of compression rings of the axially upper portion are arranged on the piston to provide an intermediate ring land 79 where blowby gases can be captured and discharged through the exhaust port.

[0267] Example 3: The ICE system of Example 1 or Example 2, wherein the at least one compression ring 78 of the axially lower portion is arranged on the piston such that the position of the at least one compression ring 78 is axially below the exhaust port at the TDC of the piston.

[0268] Example 4: The ICE system of any of the preceding examples, wherein the plurality of compression rings of the axially upper portion are arranged on the piston such that the plurality of compression rings are positioned axially below the exhaust port at the BDC of the piston.

[0269] Example 5: The ICE system of any of the preceding examples, wherein the plurality of compression rings of the axially upper portion includes at least two compression rings.

[0270] Example 6: The ICE system of any of the preceding examples, wherein the axially lower portion of the piston includes an oil control ring 76 disposed axially below the compression ring.

[0271] Example 7: The ICE system of any of the preceding examples, wherein any of the compression rings is defined by a uniform rectangular cross-section or a tapered cross-section.

[0272] Example 8: The ICE system of any of the preceding Examples 1 to 6, wherein the at least one compression ring of the axially lower portion is a Napier-type compression ring.

[0273] Example 9: The ICE system of any of the preceding examples, wherein the at least one compression ring of the axially lower portion is arranged in a groove 77 extending circumferentially around the piston skirt.

[0274] Example 10: An ICE system according to any of the preceding examples, wherein the ICE system is a spark ignition ICE system, the at least one cylinder having an ignition source 34 arranged in the combustion chamber.

[0275] Example 11: An ICE system according to any of the preceding examples, wherein the ICE system comprises an injector device for injecting fuel, the injector device being arranged in the combustion chamber.

[0276] Example 12: An ICE system according to any of the preceding examples, wherein intake air flow through the at least one intake port is controllable by an intake control valve 37 .

[0277] Example 13: An ICE system according to any one of the preceding examples, wherein the at least one cylinder is a first cylinder and the piston is a first piston, and the ICE also has a second cylinder, the second cylinder forming a pair of cylinders with the first cylinder, the second cylinder accommodating a corresponding reciprocating second piston 41 operable between a bottom dead center and a top dead center, and also at least partially defining a second combustion chamber 42 with a top end 43 of the second piston, wherein the second cylinder also includes a corresponding ignition source 44 arranged in the second combustion chamber, at least one corresponding intake port 45 arranged at the top end 46 of the second cylinder and connected to the second combustion chamber fluid, and also includes a corresponding exhaust port 48, the corresponding exhaust port being axially arranged at a position away from the top end of the second cylinder, thereby allowing the at least one corresponding intake port and the corresponding exhaust port to be separated by the piston fluid.

[0278] Example 14: The ICE system of Example 13, wherein the first cylinder and the second cylinder are separated from each other by a crank angle of 180 degrees.

[0279] Example 15: An ICE system according to Example 13 or Example 14, wherein the ICE system further comprises an intake duct 22 having a positive displacement device 23, the positive displacement device being configured to receive intake air and supply it to at least one pair of cylinders, the positive displacement device being further arranged in the intake duct to separate an upstream intake passage 24 of the intake duct from a downstream plenum 25, the downstream plenum being fluidically connected to each of a first cylinder and a second cylinder of the at least one pair of cylinders.

[0280] Example 16: An ICE system according to Example 15, wherein the intake control valve of the first cylinder can be controlled in association with the movement of the first piston and the intake control valve of the second cylinder can be controlled in association with the movement of the second piston, so that during the rotation of the crankshaft of the ICE, the fluid connection between the corresponding combustion chamber and the downstream plenum chamber is selectively opened and closed.

[0281] Example 17: The ICE system of example 15 or example 16, wherein the plenum includes an air inlet in fluid communication with the positive displacement device and a plurality of outlets configured to be in fluid communication with the intake ports of the first cylinder and the second cylinder.

[0282] Example 18: An ICE system according to any of the preceding examples 13 to 17, wherein the ICE system comprises a common crankcase housing 65 for the pair of cylinders, or the ICE system comprises a plurality of pairs of cylinders and the ICE system comprises a common crankcase housing for all cylinders of the ICE.

[0283] Example 19: An ICE system according to any of the preceding examples, wherein the ICE system is a hydrogen ICE system configured to operate on a gaseous fuel including a hydrogen-based gaseous fuel.

[0284] Example 20: A vehicle comprising an internal combustion engine system according to any one of Examples 1 to 19.

[0285] As used herein, the terms "upstream" and "downstream" refer to the relative direction of fluid flow in a fluid path. For example, "upstream" refers to the direction of fluid outflow, while "downstream" refers to the direction of fluid inflow.

[0286] Furthermore, the terms "longitudinal", "longitudinally", "axially" or "axial" refer to a direction extending at least between the axial ends of a particular component, generally along the device or component thereof in the direction of longest extension of the device and / or component. The terms "vertical" and "vertically" generally correspond to the axial direction.

[0287] The terms used herein are only for the purpose of describing specific aspects and are not intended to be limitations of the present disclosure. As used herein, unless the context clearly indicates otherwise, the singular forms "one", "a kind of" and "the" are intended to also include plural forms. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. It should also be understood that the terms "include", "comprising" when used herein specify the presence of stated features, integers, actions, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, integers, actions, steps, operations, elements, parts and / or their groups.

[0288] It should 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 element. For example, without departing from the scope of the present disclosure, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element.

[0289] Relative terms such as "below" or "above" or "upper" or "lower" or "horizontal" or "vertical" may be used herein to describe the relationship of one element to another element, as shown in the figures. It should be understood that these terms and those discussed above are intended to cover different device orientations in addition to the orientations depicted in the figures. It should be understood that when an element is referred to as being "connected" or "coupled" to another element, the element may be directly connected or directly coupled to the other element, or there may be intermediate elements. In contrast, when an element is referred to as being "directly connected to" or "directly coupled to" another element, there are no intermediate elements.

[0290] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as those commonly understood by those skilled in the art to which the present disclosure belongs. It should also be understood that, unless otherwise clearly defined herein, the terms used herein should be interpreted as meanings consistent with their meanings in the context of this specification and the relevant art, and should not be interpreted in an idealized or overly formal sense.

[0291] It should be understood that the present disclosure is not limited to the aspects described above and shown in the accompanying drawings; rather, those skilled in the art will recognize that many changes and modifications may be made within the scope of the present disclosure and the appended claims. In the drawings and description, various aspects have been disclosed for illustrative purposes only and not for limiting purposes, and the scope of the present disclosure is set forth in the appended claims.

Claims

1. A hydrogen spark ignition internal combustion engine (ICE) system (10) for a vehicle (1), the ICE system comprising: A two-stroke ICE (20) capable of operating on a hydrogen-based gaseous fuel (50), The ICE has at least one cylinder (30) with a cylinder wall (30a), and also has a reciprocating piston (31) which is movable in the cylinder in an axial direction (A) between a bottom dead center (BDC) and a top dead center (TDC), the piston extending in the axial direction and having an axial upper portion (74) having a top end (33) intended to form a part of a combustion chamber (32), and the piston also having an axial lower portion (75), The at least one cylinder and the top end of the piston at least partially define the combustion chamber, the at least one cylinder having an ignition source (34) arranged in the combustion chamber, wherein the at least one cylinder comprises at least one intake port (35) arranged at a top end (36) of the at least one cylinder and in fluid communication with the combustion chamber, The at least one cylinder further includes an exhaust port (38) disposed axially away from the top end of the at least one cylinder to allow the at least one intake port and the exhaust port to be separated by the piston fluid, and The axially upper portion of the piston includes a plurality of compression rings (71, 72) for sealing the combustion chamber, and the axially lower portion of the piston includes at least one compression ring (78), the at least one compression ring being configured to seal along an area (73) of the cylinder wall axially below the exhaust port so as to reduce leakage of blowby gases from the combustion chamber into a crankcase volume portion (69) of the ICE.

2. The ICE system of claim 1 , wherein the at least one compression ring of the axially lower portion and a compression ring of the plurality of compression rings of the axially upper portion are arranged on the piston to provide an intermediate land (79) where blow-by gases can be captured and discharged through the exhaust port.

3. The ICE system according to claim 1 or 2, wherein the at least one compression ring (78) of the axially lower portion is arranged on the piston so that the position of the at least one compression ring (78) is axially below the exhaust port at the TDC of the piston.

4. The ICE system according to any one of the preceding claims, wherein the plurality of compression rings of the axially upper portion are arranged on the piston such that the position of the plurality of compression rings is axially below the exhaust port at the BDC of the piston.

5. The ICE system according to any one of the preceding claims, wherein the plurality of compression rings of the axially upper portion comprises at least two compression rings.

6. The ICE system according to any one of the preceding claims, wherein the axially lower portion of the piston comprises an oil control ring (76) arranged axially below the at least one compression ring at the axially lower portion of the piston.

7. The ICE system of any one of the preceding claims, wherein the at least one compression ring and any of the compression rings in the plurality of compression rings are defined by a uniform rectangular cross-section or a tapered cross-section.

8. The ICE system according to any one of the preceding claims 1 to 6, wherein the at least one compression ring of the axially lower portion is a Napier type compression ring.

9. An ICE system according to any one of the preceding claims, wherein the ICE system comprises an injector device for injecting fuel, the injector device being arranged in the combustion chamber.

10. An ICE system according to any preceding claim, wherein intake air flow through the at least one intake port is controllable by an intake control valve (37).

11. An ICE system according to any one of the preceding claims, wherein the at least one cylinder is a first cylinder and the piston is a first piston, and the ICE also has a second cylinder, the second cylinder forming a pair of cylinders with the first cylinder, the second cylinder accommodating a corresponding reciprocating second piston (41) capable of operating between a bottom dead center and a top dead center, and also at least partially defining a second combustion chamber (42) with a top end (43) of the second piston, wherein the second cylinder also includes a corresponding ignition source (44) arranged in the second combustion chamber, at least one corresponding intake port (45) arranged at the top end (46) of the second cylinder and connected to the fluid of the second combustion chamber, and also includes a corresponding exhaust port (48), the corresponding exhaust port being axially arranged at a position away from the top end of the second cylinder, thereby allowing the at least one corresponding intake port and the corresponding exhaust port to be separated by the second piston fluid. 12 . The ICE system of claim 11 , wherein the first cylinder and the second cylinder are separated from each other by a crank angle of 180 degrees.

13. The ICE system according to claim 11 or 12 further comprises an intake duct (22), the intake duct having a positive displacement device (23), the positive displacement device being configured to receive intake air and supply it to the pair of cylinders, the positive displacement device being further arranged in the intake duct to separate an upstream intake passage (24) of the intake duct from a downstream plenum (25), the downstream plenum being fluidically connected to each of the first cylinder and the second cylinder of the pair of cylinders.

14. The ICE system of claim 13, wherein the intake control valve of the first cylinder is controllable in association with movement of the first piston and the intake control valve of the second cylinder is controllable in association with movement of the second piston, so that during rotation of the crankshaft of the ICE, the fluid connection between the corresponding combustion chamber and the downstream plenum chamber is selectively opened and closed.

15. An ICE system according to any one of claims 11 to 14, wherein the ICE system comprises a common crankcase housing (65) for the pair of cylinders, or the ICE system comprises a plurality of pairs of cylinders and the ICE system comprises a common crankcase housing for all cylinders of the ICE.

16. A vehicle comprising an internal combustion engine system according to any one of claims 1 to 15.

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