Internal combustion engine system

Abstract

An internal combustion engine system, in particular a spark-ignition internal combustion engine (ICE) system for a vehicle, comprising a two-stroke ICE; a first cylinder housing a reciprocating first piston operable between a bottom dead center and a top dead center and further defining a first combustion chamber at least partially with a top end of the first piston; at least one intake port disposed at a top end of the first cylinder and in fluid communication with the combustion chamber; the exhaust port is formed in the far side of the top end of the first air cylinder; a second cylinder housing a reciprocating second piston operable between a bottom dead center and a top dead center, and further defining a second combustion chamber at least partially with a top end of the second piston; at least one corresponding intake port disposed at a top end of the second cylinder and in fluid communication with the second combustion chamber; and further includes a corresponding exhaust port disposed distal to the top end of the second cylinder, the pair of first and second cylinders being disposed at a 180 degree crank angle from each other.

Description

Technical Field

[0001] The present disclosure generally relates to an internal combustion engine system and a method of operating an internal combustion engine system. 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, for example, be applicable to other types of vehicles propelled by an internal combustion engine, such as sedans and other lightweight and light vehicles, etc. In addition, the internal combustion engine of the internal combustion engine system may generally be an internal combustion engine that can be operated 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, reducing exhaust gas, improving engine efficiency (i.e. reducing fuel consumption) and reducing the noise level of the engine are some of the criteria that have become more important aspects when designing and selecting suitable internal combustion engine (ICE) systems and their engine components. Furthermore, in the field of heavy vehicles such as trucks, there are many current environmental regulations that set specific requirements for vehicles, such as restrictions 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 they are simply fed 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, it is necessary that the modification is not too complicated and not too expensive. Summary of the invention

[0004] According to a first aspect of the present disclosure, a spark ignition internal combustion engine (ICE) system for a vehicle is provided. The ICE system includes a two-stroke ICE that can be operated with gaseous fuel or liquid fuel. The ICE has at least one pair of first and second cylinders, and the at least one pair of first and second cylinders has corresponding first and second cylinder walls. The first cylinder accommodates a first reciprocating piston operable between a bottom dead center and a top dead center, and also at least partially defines a first combustion chamber with the top end of the first piston, wherein the first cylinder also includes: an ignition source arranged in the first combustion chamber, at least one intake port arranged at the top end of the first cylinder and connected to the combustion chamber fluid, wherein the flow of combustible gas through the at least one intake port can be controlled by an intake control valve, and the first cylinder also includes an exhaust port, which is arranged on the far side of the top end of the first cylinder, so that when the first piston is at its top dead center, at least one intake port and exhaust port are located at different positions and separated by the piston top end, the second cylinder accommodates a second reciprocating 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, a top end of the second cylinder arranged at least one corresponding intake port at the end thereof and connected to the fluid of the second combustion chamber, wherein the flow of combustible gas through the at least one corresponding intake port can be controlled by a corresponding intake control valve, and the second cylinder also includes a corresponding exhaust port, the corresponding exhaust port being arranged on the far side of the top end of the second cylinder, so that when the second piston is at its top dead center, the at least one corresponding intake port and the corresponding exhaust port are located at different positions and are separated by the top end of the piston, the pair of first cylinders and second cylinders being arranged to be separated from each other by a crank angle of 180 degrees; and an intake duct, the intake duct including a positive displacement device, the positive displacement device being configured to receive intake air and feed the intake air to the at least one pair of cylinders, the positive displacement device being further arranged in the intake duct to separate the upstream intake passage of the intake duct from the downstream plenum, and being configured to allow the downstream plenum to be fluidically connected to each of the first cylinder and the second cylinder of the at least one pair of cylinders.

[0005] A first aspect of the present disclosure may seek to provide an improved two-stroke ICE system that is controllable to prevent pressure pulses from being transmitted into the intake system, thereby avoiding or at least reducing flashback. Technical benefits may include increased versatility in combustion chamber temperature control. Furthermore, the proposed ICE system allows for a reduction in ignition timing while reducing the risk of flashback into the intake system of the ICE system.

[0006] Insofar as the positive displacement device is arranged in the intake duct, the displacement device is arranged to eliminate or at least reduce the risk of pressure pulses being transmitted from the combustion chamber back to the upstream intake port of the intake duct.

[0007] The intake port is thus mechanically isolated from the intake duct. The positive displacement device is therefore arranged to seal the cylinder and the downstream intake plenum from the upstream intake duct of the intake duct (intake manifold) in the event of a backfire.

[0008] Furthermore, with respect to the arrangement and configuration of the displacement device in the intake duct, the displacement device can still provide uniform flow by feeding alternate pairs of cylinders.

[0009] Furthermore, the proposed ICE system may suppress the knock and / or auto-ignition tendency of a fuel, such as a gaseous fuel, for example a hydrogen-based fuel.

[0010] By arranging the corresponding intake and exhaust ports of the cylinder at different positions, the corresponding piston will provide a blocking effect 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 / cylinder liner) will be completely isolated from the combustible gas (usually corresponding to the air / fuel mixture).

[0011] Therefore, the proposed ICE system implements a length scavenging system that separates the hot exhaust end of the cylinder from the cold intake end where combustibles are present. Therefore, the knock risk can be greatly reduced by the proposed ICE system.

[0012] By arranging a pair of first and second cylinders to be spaced 180 crank angle degrees apart from each other, the two cylinders may provide a 180 degree cycle interval regardless of the ICE and cylinder arrangement / configuration.

[0013] In summary, the proposed ICE system provides a separate intake plenum for each pair of cylinders with combustion phases spaced 180 degrees apart, wherein the intake duct has a close-coupled positive displacement device for each pair of cylinders. It should be noted that the proposed ICE system may not be limited to a system with a single 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.

[0014] Thus, an ICE system is provided having forced induction at the top of the cylinder; an ignition source for igniting the fuel while being configured to expel exhaust gas through exhaust ports in the lower to mid-portion of the cylinder (e.g., the lower portion of the cylinder wall / liner).

[0015] Furthermore, the proposed two-stroke ICE (which can advantageously be operated with hydrogen or any other gaseous fuel) improves BMEP potential due to doubling of firing frequency. Specifically, the two-stroke cycle enables the ICE to operate at higher lambda values ​​while maintaining power density compared to a four-stroke ICE.

[0016] "Two-stroke operation" or "two-stroke mode" refers to a cycle of an internal combustion engine in which the piston moves two strokes (up and down) between TDC and BDC during only one revolution of the crankshaft in order to complete one complete working cycle. Generally speaking, when the internal combustion engine is operated in a typical two-stroke mode, the operation of the internal combustion engine corresponds to repeated engine operation for each revolution of the crankshaft.

[0017] In some examples, including at least one preferred example, optionally, the pair of first and second cylinders may be arranged 180 crank angle degrees apart from each other to provide a 180 degree combustion phasing interval.

[0018] 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.

[0019] 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.

[0020] In some examples, including at least one preferred example, the ignition source may alternatively be any of a spark plug and a glow plug.

[0021] In some examples, including at least one preferred example, each of the intake control valve and the corresponding intake control valve may optionally be arranged to open and close a fluid passage of the corresponding intake port, thereby controlling the flow of fluid to the corresponding combustion chamber.

[0022] In some examples, including at least one preferred example, the ICE system may optionally include a fuel injector device arranged in a downstream plenum of the intake conduit to provide fuel injection upstream of the intake ports of the first cylinder and the second cylinder. Technical benefits may include improved fuel injection to the combustion chamber of the ICE. Here, the ICE system is configured to provide port injection of gaseous fuel or liquid fuel.

[0023] The use of port injection allows for a homogeneous mixture to be provided, which enables improved knock and auto-ignition control and also helps to reduce emissions.

[0024] Alternatively, the fuel injector device may be arranged in each of the combustion chambers of the first cylinder and the second cylinder, respectively.

[0025] 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 travels into the corresponding combustion chamber. Technical benefits may include an improved scavenging effect. Thus, the ICE system is configured to provide a scavenging effect through injection timing in the intake port. The fuel injector device is generally operable in response to a predetermined fuel injection event.

[0026] In some examples, including at least one preferred example, the fuel injector arrangement may optionally be controllable to provide sequential fuel injection to the first cylinder and the second cylinder so as to allow active cylinder scavenging during a later portion of a corresponding intake stroke of a corresponding one of the first cylinder and the second cylinder. In other words, the sequential injection may enable active cylinder scavenging (clearing the exhaust) during a later portion of the intake stroke, thereby generating a final pressure pulse (from the injected fuel) that increases the retained mass in the cylinder after any exhaust port and intake valve closure. Furthermore, the generated pressure pulse may increase the scavenging effect.

[0027] In some examples, including at least one preferred example, optionally, the intake control valve of the first cylinder can be controlled according to the movement of the first piston, and the intake control valve of the second cylinder can be controlled according to the movement of the second piston, so that the fluid communication between the corresponding combustion chamber and the plenum chamber is selectively opened and closed during the crankshaft rotation of the ICE. Technical benefits may include further reducing the risk of flashback.

[0028] In some examples, including at least one preferred example, optionally, the plenum can 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 can include an improved air supply system for supplying air to the cylinders. For example, the plenum is a Siamese design.

[0029] In some examples, each of the cylinder heads of the first cylinder and the second cylinder may have a plurality of 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 a plurality of four intake control valves. Technical benefits may include an even more improved air supply system for supplying air to the cylinders. The configuration of an ICE system having four intake control valves per cylinder may be particularly beneficial for a two-stroke operated ICE system that may generally have a shorter intake cycle than a four-stroke ICE system. The configuration of an ICE system having four intake control valves per cylinder allows an increase in the air intake rate into the combustion chamber of the cylinder. In addition, it may improve the scavenging phase of discharging (pushing out) the exhaust gas in a uniform pressure wave manner.

[0030] 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 for supplying air to cylinders during operation of an ICE system. Variable valve actuation can also allow for adjustment of phase (valve timing) to achieve better pulse capture and efficiency in synchronization with fuel injection and corresponding pulses in a plenum chamber.

[0031] 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 air flow and / or pressure 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 also improves the functionality of the ICE system overall.

[0032] 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 may be further improved.

[0033] In some examples, including at least one preferred example, the ICE system may optionally include additional cylinder pairs with corresponding intake ducts and positive displacement devices.

[0034] 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.

[0035] In some examples, including at least one preferred example, the ICE system may optionally further include a turbocharger arrangement 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 so as to drive the turbocharger compressor.

[0036] In some examples, including at least one preferred example, the ICE system may optionally further include an exhaust gas recirculation (EGR) system including an EGR conduit arranged to connect the exhaust duct and the intake duct to allow exhaust gas to recirculate through the cylinders during ICE operation.

[0037] In some examples, including at least one preferred example, the EGR system may optionally further include a corresponding positive displacement device.

[0038] 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.

[0039] In some examples, including in 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 may generally have a higher auto-ignition temperature; however, low ignition energy is only required when a spark (or glowing surface or particle) is present. However, the low ignition energy may pose some challenges to the ICE, for example, it may be difficult to use the cylinder head when the hot exhaust port / door is located in the same combustion chamber as the intake port / door, or when it is located near the compressed air / fuel mixture before ignition. The technical benefits of using the proposed ICE system with hydrogen-based fuels may include a more reliable and more robust hydrogen ICE system.

[0040] 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 (such as an electronic control unit including processing circuits). 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.

[0041] In some examples, including at least one preferred example, the ICE system may optionally be configured to be controllable to terminate fuel injection during the intake phase and before the intake valve closes, 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. For example, the ICE system may include a controller configured to terminate fuel injection during the intake phase and before the intake valve closes, 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.

[0042] In some examples, including at least one preferred example, the ICE system may optionally include a set of multiple cylinder pairs having corresponding intake ducts with corresponding positive displacement devices.

[0043] 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.

[0044] It will be appreciated by those skilled in the art that the disclosed aspects, examples (including any preferred examples), and / or the appended claims may be appropriately combined with each other. Additional features and advantages are disclosed in the following description, claims, and drawings, and will in part be apparent to those skilled in the art or recognized by practicing the disclosure as described herein. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Examples are described in more detail below with reference to the accompanying drawings.

[0046] Figure 1 is an exemplary embodiment of the present disclosure, including a side view of a vehicle in the form of a truck according to one example.

[0047] Figure 2 An internal combustion engine system according to one example is shown.

[0048] Figure 3 An internal combustion engine system according to one example is shown.

[0049] FIG. 4A to FIG. 4D Shows Figure 2 and / or Figure 3 An example of a combustion cycle for an internal combustion engine system in FIG. DETAILED DESCRIPTION

[0050] 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.

[0051] For internal combustion engine systems, it may be desirable to control the risk of flashback, i.e. the condition when a flame escapes from the combustion chamber of a cylinder and travels upstream into the intake duct. It has also been observed that managing auto-ignition and flashback in a reliable manner is particularly useful for hydrogen ICE systems.

[0052] The present disclosure may seek to provide an improved two-stroke ICE system that is controllable to prevent pressure pulses from entering the intake system, thereby avoiding or at least reducing flashback. Technical benefits may include increased versatility in combustion chamber temperature control. In addition, the two-stroke ICE system allows for reduced ignition timing while reducing the risk of flashback entering the intake system of the ICE system.

[0053] Figure 1 is an exemplary embodiment of the present disclosure, comprising a side view of a vehicle 1 in the form of a truck according to one example.

[0054] 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.

[0055] 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. Here, the controller 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.

[0056] Figure 2 An example of an ICE system 10 is shown. By way of example only, Figure 2 The ICE system 10 can be used for Figure 1 The following will be about the vehicle 1. Figure 2 and Figures 4A to 4D The ICE system 10 is described.

[0057] Here, the ICE system 10 is a spark ignition ICE system. The ICE system 10 includes a two-stroke ICE 20 that can operate with a gas fuel 50 or a liquid fuel 50. An example of a gas 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.

[0058] 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 such a hydrogen ICE system 10 is based on the combustion of air and hydrogen, as is well 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 is well 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 gas. The hydrogen ICE system 10 as described herein contributes to the leaner operation of the ICE 20, which is advantageous from the perspective of NOx emissions.

[0059] like Figure 2 And further in FIG. 4A to FIG. 4D As depicted in FIG. 2 , 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.

[0060] Here, the first cylinder 30 and the second cylinder 40 are a pair of first cylinders 30 and second cylinders 40. Typically, although not strictly required, the first cylinder 30 and the second cylinder 40 here are a pair of adjacent first cylinders 30 and second cylinders 40. In the present context, the term "adjacent" generally means that the cylinders are arranged adjacent to each other, i.e., adjacent to each other within the ICE system, thereby allowing a pair of cylinders that operate according to a 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 ICE 20. 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, as long as the first cylinder and the second cylinder work as a pair of cylinders, the cylinders can be arranged slightly away from each other, i.e., the cylinders are connected to the same crankshaft and are spaced 180 crank angle degrees apart, as further described herein.

[0061] It should be noted that 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 .

[0062] like Figure 2As 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 operatively connected to a corresponding piston, as further described below.

[0063] The ICE system 20 may also include an oil sump 62 and an oil splash plate 68. These components are conventional parts of an ICE and are not further described herein.

[0064] 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.

[0065] More specifically, if combined Figure 4D from Figure 4A As can be seen in FIG. 1 , 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 located 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.

[0066] The first piston 31 can generally include a suitable number of piston rings. For example, the first piston 31 includes one or more compression rings and oil control rings. 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 top end 33 of the first piston 31.

[0067] 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 combustion chamber 32 is arranged at the end of the first cylinder 30 (ie, the first cylinder head 30b) so that an upper surface of the top end 33 defines a lower side of the first combustion chamber 32.

[0068] 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 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 2 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.

[0069] Ignition source 34 is configured to ignite hydrogen supplied via a fuel device, as described herein. For example, the ignition source is a spark plug 17. A spark plug is a device for transferring 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 controlling combustion pressure within the engine.

[0070] 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. Here, the top end 36 is a component of the cylinder head 30b.

[0071] Additionally, the flow of the combustible gas through the at least one air intake port 35 may be controlled by an air intake control valve 37. In this example, the combustible gas may typically comprise a mixture of air and port injected hydrogen (gaseous fuel).

[0072] 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 .

[0073] Furthermore, the first cylinder 30 of the ICE 20 includes an exhaust port 38 disposed distally of a 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 .

[0074] More specifically, if Figure 2 As shown, the first cylinder 30 includes a first exhaust port 38. The first exhaust port 38 is configured to exhaust the combusted gas from the first cylinder 30. The first exhaust port 38 is arranged distal to 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 separated by the top end 33. In this context, the term "distal end" means that the exhaust port 38 is arranged to be separated from the top end 33 in the direction Z of the cylinder 30 corresponding to the axial direction of the piston 31. Therefore, the top end 33 is considered to be a proximal portion of the first cylinder 30. In other words, the first piston 31 is arranged in the first cylinder 30 to reciprocate along the central axis ZA1, here, extending in 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 to be located axially far from the top end 33 of the first cylinder 30 in the axial direction of the first cylinder 30 and the first piston 31 (here, corresponding to the direction Z).

[0075] For example, the exhaust port 38 is disposed at a lower to middle portion 39 of the first cylinder 30 .

[0076] In some examples, such as Figure 2 As shown, when the first cylinder 30 includes a first cylinder liner, here, the cylinder liner also includes an exhaust port 38 located at a lower to middle portion 39 of the cylinder liner. Therefore, the exhaust port 38 is generally arranged at a distal side of the top end 33 of the first cylinder 30 and is positioned in the cylinder wall 30a of the cylinder liner of the first cylinder 30.

[0077] 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.

[0078] More specifically, if combined Figure 4D from Figure 4A As can be seen, the second piston 41 is arranged in the second cylinder 40 at BDC ( Figure 4A ) and TDC ( Figure 4D ) reciprocates between. Figure 4A , the second piston 41 is located 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.

[0079] The second piston 41 can generally include a suitable number of piston rings. For example, the second piston 41 includes one or more compression rings and oil control rings. 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 top end 43 of the second piston 41.

[0080] 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 the upper surface of the top end 43 defines the lower side of the second combustion chamber 42.

[0081] Each of the piston tops may have a flat top or the piston top may be slightly concave in order to avoid hot spots.

[0082] The second cylinder 40 further 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 at a position facing the combustion chamber 42. For example, the ignition source 44 is arranged at the upper end of the combustion cylinder 40, such as 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.

[0083] Here, each of the ignition sources 34, 44 is a spark plug. The ignition source could also be a glow plug.

[0084] 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.

[0085] 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. Here, the top end 46 is an integral part of the cylinder head 40b.

[0086] Additionally, the flow of the combustible gas through at least one corresponding air inlet 45 may be controlled by a corresponding air inlet control valve 47. In this example, the combustible gas may typically include a mixture of air and port injected hydrogen (gaseous fuel).

[0087] 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 .

[0088] In addition, the second cylinder 40 of the ICE 20 includes a corresponding exhaust port 48, which is arranged at a distal side of 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.

[0089] Similar to the first cylinder and its exhaust port, the corresponding exhaust port 48 is configured to exhaust combustion gas from the second cylinder 40. The corresponding exhaust port 48 is arranged distal to 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 separated by the top end 43. In this context, the term "distal" means that the exhaust port 48 is arranged to be spaced apart from the top end 43 in the direction Z of the second cylinder 40 corresponding 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.

[0090] More specifically, the second piston 41 is arranged in the second cylinder 40 to reciprocate along the center axis ZA2, here, extending in the direction Z. 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 to be located axially far from the top end 43 of the second cylinder 40 in the axial direction of the second cylinder 40 and the second piston 41 (here, corresponding to the direction Z).

[0091] For example, the exhaust port 48 is arranged at a lower to middle portion 49 of the second cylinder 40. The exhaust port 48 is arranged at a lower to middle portion 49 of the second cylinder 40 as can be seen along the center axis ZA2.

[0092] It should be noted that Figure 2 , 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 crank angle degrees apart from each other.

[0093] In some examples, such as Figure 2 As shown, when the second cylinder 40 includes a second cylinder liner, the cylinder liner also includes a corresponding exhaust port 48 located at a lower to middle portion 49 of the cylinder liner. Therefore, the corresponding exhaust port 48 is generally arranged at the far side of the top end 43 of the second cylinder 40 and is positioned in the cylinder wall 40a of the cylinder liner of the second cylinder 40.

[0094] like Figure 2 As shown, the pair of adjacent first cylinder 30 and second cylinder 40 are arranged to be spaced 180 crank angle degrees (180 CAD) from each other. In this way, the cylinders 20, 30 are spaced from each other to provide a 180 degree combustion phase interval. Therefore, the cylinders 30, 40 can be arranged in the ICE system 10 to provide a 180 degree cycle interval regardless of the ICE and cylinder arrangement / configuration.

[0095] By arranging the exhaust ports 38, 48 in the lower to middle portion of the cylinders 30, 40, when the respective pistons are at their TDC, the respective 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 respective piston tops 33, 43. Therefore, by arranging the respective 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 respective pistons are at their TDC, the respective pistons will provide a blocking effect between the intake ports and the exhaust ports, so that the hot portions of the cylinders (exhaust ports and cylinder walls / cylinder liners) will be completely isolated from the combustible gas (air). Figure 2 as well as Figure 4A and Figure 4D The blocking effect is at least schematically shown in FIG.

[0096] Thus, the configuration of the intake and exhaust ports enables a length scavenging ICE system that separates the hot exhaust end of each cylinder from the cold intake end where combustibles are present. Thus, the risk of knocking can be reduced during operation of the ICE system 10. Compared to a two-stroke diesel ICE using multiple cylinders, this also allows for reverse scavenging of the corresponding combustion chambers via controllable intake valves in the cylinder head and exhaust ports 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.

[0097] By combining the arrangement of the ignition sources 34, 44 with the locations of the intake ports 35, 45 and exhaust ports 38, 48, the ICE system 10 is configured to provide forced induction at the top of the cylinder; an ignition source for igniting the fuel in each combustion chamber 32, 42, while also being configured to discharge exhaust gas through the corresponding exhaust ports 28, 38 in the lower to mid-portion of the corresponding cylinder (e.g., the lower portion of the wall 30a, 40a of the cylinder liner).

[0098] In addition, if Figure 2 As depicted, the ICE system 10 includes an intake conduit 22. The intake conduit 22 is a manifold that is arranged and configured to feed intake air to cylinders, in this example a first cylinder 30 and a second cylinder 40.

[0099] The intake duct 22 includes a positive displacement device 23, such as Figure 2 As shown. The positive displacement device 23 is configured to receive intake air 51 and feed the intake air 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 upstream intake duct 22 from the downstream plenum 25.

[0100] 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 some parts of the intake duct may be an integral part of the cylinder head of the cylinder.

[0101] 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 discharge its (full) internal displacement per revolution.

[0102] Here, the positive displacement device 23 is a positive displacement pump configured to discharge gas from an upstream position of the intake duct 22 to a downstream position by capturing a fixed amount of air and pushing the captured amount of air from an upstream position to a downstream position.

[0103] 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 can also be readily appreciated.

[0104] Here, the positive displacement device 23 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 can generally operate with flow and pressure as independent variables. This means that if the pressure increases and the speed remains unchanged, 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.

[0105] The positive displacement device 23 may be electrically driven, hydraulically driven, etc. An electrified positive displacement device may also improve turbo transients by boosting with scavenged air, which may also drive the turbine in the turbine. Such a configuration of an ICE system may allow for pressure reduction before the displacement pump and / or after the turbo compressor, thereby immediately reducing the work of the compressor.

[0106] Here, the upstream air intake passage 24 is a component of the air intake duct 22. By way of example, the air intake duct 24 is provided in the form of a cylindrical housing having an inner volume. A plenum 25 is also typically a component of the air intake duct 22.

[0107] In addition, if Figure 2 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 2 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 .

[0108] exist Figure 2 In the embodiment, the downstream plenum 25 is arranged in the form of a so-called Siamese design. Such a Siamese design has a first inlet duct 25a and a set of two outlet ducts 25b, 25c, such as Figure 2 The diameter and length of the inlet and outlet conduits may vary depending on the type of ICE system 10, and Figure 2 The gas collecting chamber 25 is shown only schematically.

[0109] 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.

[0110] 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 2 As depicted in .

[0111] 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, so minimizing the volume may be beneficial in view of the other volumes of other components.

[0112] 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 .

[0113] 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 having a 180 CAD spacing, air will continue to flow through the positive displacement device 23 as the pair of cylinders 30, 40 interact with respect to intake events.

[0114] With respect to the arrangement of 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 .

[0115] The intake ports 35, 45 are therefore mechanically isolated from the intake passage 24. The positive displacement device 23 is therefore arranged to seal the cylinders 30, 40 and the downstream plenum 25 from the upstream intake passage 24 of the intake duct 22 (intake manifold) in the event of a flashback.

[0116] Moreover, with respect to 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 feeding the cylinder pairs 30 , 40 .

[0117] Furthermore, the proposed ICE system can suppress the knock and / or auto-ignition tendency of a fuel, such as a gaseous fuel, for example a hydrogen-based fuel. This is provided, for example, by a combination of having a separate intake plenum 23 for each pair of cylinders 30, 40 with a combustion phase interval of 180 degrees and wherein the intake duct 22 has a close-coupled positive displacement device 23 for each pair of cylinders 30, 40. By arranging the positive displacement device 25 close to the cylinder, the internal volume of the plenum 25 can be minimized, thereby providing even more effective flashback protection.

[0118] Here, the ICE system 20 includes a fuel injector assembly 26 such as Figure 2 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, injection of fuel into the combustion chambers 32, 42 of the ICE 20 may be improved.

[0119] The fuel injector assembly 26 includes at least one fuel injector configured to inject fuel. Figure 2 In the embodiment of the present invention, the fuel injector arrangement 26 includes a set of two fuel injectors 26a, 26b. Typically, there is one fuel injector 26a, 26b 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 ports 35, 45. The use of port injection allows a homogeneous mixture to be provided, which enables improved knock and auto-ignition control, and helps reduce emissions.

[0120] The fuel injector device 26 can be operated / controlled in response to a fuel injection event so that the fuel injection is injected into one or more of the corresponding intake ports 35, 45, so that a pressure pulse is generated in the plenum 25 and then travels to 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 in the corresponding intake ports 35, 45.

[0121] For example, the fuel injector arrangement 26 is operable / controllable to provide sequential fuel injection to the cylinders 30 , 40 so as to enable active cylinder scavenging during a rear portion of a corresponding intake stroke of a corresponding one of the cylinders 30 , 40 .

[0122] In other words, sequential injection enables active cylinder scavenging (emptying the exhaust) during the latter part 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 may also result in the plenum and / or intake ports being empty of fuel after the intake valve closes.

[0123] Furthermore, the pressure pulses generated increase the scavenging effect.

[0124] It may be noted that sequential injection can be adjusted for different speeds and valve timings.

[0125] Generally speaking, the pressure pulse will also propagate backward in the downstream plenum 25. For example, the pressure pulse will be reflected in the closed sister cylinder intake valve. Thereafter, the pressure pulse travels back 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.

[0126] In some examples, although not shown, the fuel injectors 26 a , 26 b of the fuel injector arrangement 26 may be arranged in each of the combustion chambers of the cylinders.

[0127] Turning again to the air inlet 35, 45 and the air inlet valve 37, 47, here, Figure 2 The ICE system 10 in FIG. 1 is provided with a plurality of two intake valves 37 for the first cylinder 30 and a plurality of two intake control valves 47 for the second cylinder 40 .

[0128] Therefore, in some examples, each of the cylinder heads 30b, 40b includes a plurality of 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 a plurality of intake control valves. For example, each of the cylinder heads may have a plurality of four intake control valves. Such a configuration provides an even 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 that can operate with hydrogen-based fuels, because the two-stroke ICE system has a shorter intake cycle than 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 air intake rate of the combustion chambers 32, 42 of the cylinders 30, 40, thereby also improving volumetric efficiency. To this end, the ICE system 10 including the arrangement of the positive displacement device 23 in combination with an arrangement of four intake valves in each cylinder enables even greater improvements in volumetric efficiency at least compared to conventional ICE systems, such as four-stroke ICE systems.

[0129] exist Figure 2In some examples, the intake control valves 37, 47 are configured to provide variable valve actuation. Variable valve actuation can be provided by a hydraulic system, an electronic system, or a pneumatic system. However, the intake control valves 37, 47 can also be conventional intake control valves, such as camshaft-based systems commonly used in diesel ICE systems. Therefore, 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 can also include variable valve actuation.

[0130] exist Figure 2 In the embodiment, the ICE system 10 includes an inlet control valve actuation assembly 63 for actuating at least one inlet control valve 37 and a corresponding inlet control valve 47. The inlet valve actuation assembly 63 is adapted to actuate the inlet 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 is given.

[0131] If also from Figure 2 As can be seen, 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.

[0132] Figure 3 is another example of the ICE system 10. Here, the ICE system 10 includes Figure 2 and Figures 4A to 4D Features and components of the ICE system 10 are described. Figure 3 The ICE system 10 shown in FIG. Figure 2 The ICE system shown in FIG. 1 is different in that the ICE system 10 further includes a turbocharger device 70. The turbocharger device 70 includes a turbocharger turbine 71 operatively connected to a turbocharger compressor 72, wherein the turbocharger compressor 72 is arranged in an intake duct 73 in fluid communication with the intake duct 22. The turbocharger turbine 71 is arranged in the exhaust duct 61 so as to drive the turbocharger compressor 72. In other words, the turbine 71 is configured to convert engine exhaust gas into mechanical energy to drive the compressor 72.

[0133] The turbocharger turbine 71 may be a conventional turbine used in the ICE system 10. Alternatively, the turbocharger turbine 71 may be a variable geometry turbine in fluid communication with the cylinders.

[0134] exist Figure 3 , the ICE system 10 further comprises an exhaust gas recirculation (EGR) system 80 comprising an EGR conduit 81 arranged to connect the exhaust gas conduit 61 and the intake conduit 22 so as to allow exhaust gas to recirculate through the cylinders during operation of the ICE 20 .

[0135] Here, the EGR system 80 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. The positive displacement device 82 is, for example, a Roots blower.

[0136] The EGR conduit 81 connects to the intake conduit 73 at a location 84 downstream of the turbocharger compressor 72 and further connects to the exhaust conduit 61 at a location 85 upstream of the turbocharger turbine 71 .

[0137] Usually, if Figure 3 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 73. More specifically, as seen in the flow direction from the compressor 72 to the intake duct 22, the CAC 67 is arranged in the intake duct 73 and between the turbocharger compressor 72 and the intake duct 72.

[0138] It should be easy to understand that Figure 2 and / or Figure 3 The intake duct of may have its own inlet for receiving fresh air from the outside and / or be configured to receive air from the intake conduit 73 .

[0139] For Figure 3 In the illustrated ICE system 10 with a turbocharger 70, the positive displacement device 23 can operate in conjunction with the upstream mounted turbine in a number of ways:

[0140] If the intake air flow is at the desired level, the positive displacement device 23 rotates to move the air volume past the rotor. In this case, the positive displacement device consumes little energy because no compression occurs. Then, the portion of the intake duct 22 that blocks the upstream intake duct 24 also plays a role (depending on the design).

[0141] If in a transient state and the turbocharger has not yet spun up, the positive displacement device 23 can spin up 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 can lead to knock tendencies or NO x By controlling the air during the transient with additional boost, this problem can be eliminated or at least reduced to a large extent.

[0142] At some operating points where the turbine is insufficient to provide boost, the positive displacement device 23 may be supported by additional boost to improve control of the air / fuel ratio, cylinder scavenging etc., ie combustion control.

[0143] In addition, regarding Figure 2 and / or Figure 3 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 .

[0144] 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 .

[0145] Below, there is an example of an operational sequence of the ICE system 10 during two-stroke operation. FIG. 4A to FIG. 4D The sequence of two-stroke operation is described.

[0146] 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 and is located in the upper half of the corresponding cylinder, the compression event occurs. When the corresponding piston travels from TDC to BDC and is located 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 located in the lower half of the corresponding cylinder. For example, when the corresponding piston is located in the lower half of the cylinder and travels toward its BDC, passes through its BDC and / or when the corresponding piston is located in the lower half of the cylinder and travels toward its TDC, exhaust and intake events occur.

[0147] However, it should be noted that the exhaust and intake events may occur in different areas of the cylinder and may be slightly separated, but the exhaust and intake events will generally occur simultaneously. During the exhaust and intake events, the ICE system provides a scavenging effect, where fresh intake air pushes residual exhaust gas out of the exhaust port.

[0148] 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 approximately 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).

[0149] More specifically, if FIG. 4A to FIG. 4DAs shown, the intake control valve 37 of the first cylinder 30 can be operated according to the movement of the first piston 31, and the intake control valve 47 of the second cylinder 40 can be operated according to the movement of the second piston 41. In this way, the fluid communication between the respective combustion chambers 32, 42 and the plenum 25 is selectively opened and closed during the crankshaft rotation of the ICE 20. As mentioned herein, such a 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.

[0150] The inlet control valve 37 and the corresponding inlet control valve 47 are controlled and actuated by an inlet control valve actuation assembly 63. Purely by way of example, the inlet control valve actuation assembly 63 may include an electric actuator (not shown) adapted to actuate the inlet control valve in at least two lift modes, i.e. between an open mode and a closed mode.

[0151] Furthermore, as mentioned above, the cylinders 30, 40 are spaced 180 degrees crank angle apart from each other. Such an arrangement and configuration of the ICE system 20 allows for a 180 degree combustion phase interval. The effect of the intake valve on the control of the intake port in conjunction with the 180 degree combustion phase interval can be achieved by Figure 4A and Figure 4D The following diagram is used as an example:

[0152] exist Figure 4A In the embodiment, the first intake port 35 of the first cylinder 30 is closed by the inlet control valve 37 to close the fluid communication between the first combustion chamber 32 and the plenum 25, while the corresponding intake port 45 of the second cylinder 40 is opened by the inlet control valve 47 to provide fluid communication between the second combustion chamber 42 and the plenum 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 inlet control valve 37 is therefore closed. In addition, in Figure 4A In FIG. 4 , the second piston 41 is at its BDC and the corresponding inlet 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, i.e., fresh intake air from the intake port 45 enters the second cylinder 40 and pushes the residual exhaust gas out of the exhaust port 48. Since there is a 180 degree crank angle interval between the cylinders 30, 40, the operation of the first piston 31 and the second piston 41 can be performed simultaneously, and a 180 degree combustion phase interval is also provided here.

[0153] 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 inlet control valve 37 is closed. In addition, as shown in FIG. Figure 4BAs 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 inlet control valve 47 is partially open, as shown in FIG. Figure 4B Since there is a 180 degree crank angle interval between the cylinders 30 and 40, the operation of the first piston 31 and the second piston 41 can be performed simultaneously, and a 180 degree combustion phase interval is also provided here.

[0154] exist Figure 4C , 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 inlet control valve 37 is controlled to move from its closed position to an open position. Figure 4C , the inlet control valve 37 is shown in a partially open position. Figure 4C As shown, the second piston 41 is close to its TDC, and the corresponding inlet 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 there is a 180 degree crank angle interval between the cylinders 30, 40, the operation of the first piston 31 and the second piston 41 can be performed simultaneously, and a 180 degree combustion phase interval is also provided here.

[0155] Finally, if Figure 4D As shown, the first piston 31 is at its BDC and the corresponding inlet control valve 37 of the first cylinder 30 is fully open. Here, the first cylinder 30 and the first piston 31 are in positions corresponding to exhaust and intake events, that is, 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 inlet control valve 47 is therefore closed. Since there is a 180-degree crank angle interval between the cylinders 30 and 40, the operation of the first piston 31 and the second piston 41 can be performed simultaneously, and a 180-degree combustion phase interval is also provided here.

[0156] If also from Figure 4D It can be seen that the inlet control valve 37 at the first intake port 35 of the first cylinder 30 is opened to provide fluid communication between the first combustion chamber 32 and the accumulator chamber 25, while the corresponding intake port 45 of the second cylinder 40 is closed by the inlet control valve 47 to close the fluid communication between the second combustion chamber 42 and the accumulator chamber 25.

[0157] In addition, if FIG. 4A to FIG. 4DIt can be seen that since the first cylinder 30 and the second cylinder 40 are arranged to be separated from each other by 180 crank angle degrees, 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 is at a half position in the cylinder, the intake valves 37, 47 of the cylinders 30, 40 are fully closed, which can further reduce the risk of backfire.

[0158] Thus, by combining the arrangement of the first cylinder 30 and the second cylinder 40 being spaced 180 crank angle degrees apart from each other with the arrangement of the positive displacement device 23, such as for example Figure 2 Combination FIG. 4A to FIG. 4D As shown, the risk of flashback can be reduced.

[0159] In addition, despite FIG. 4A to FIG. 4D It is not explicitly shown in the figure, but it should be easily understood that upon injection, after scavenging has begun, 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, while also increasing the pressure in the cylinder. However, the positive displacement device 23 acts as a check valve and also increases the boost pressure momentarily during the pulse, while limiting the pulse from traveling backward in the intake duct (intake system).

[0160] 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, thereby improving efficiency.

[0161] Furthermore, because the two-stroke cycle of the ICE system 10 provides twice as many power cycles per revolution as a conventional four-stroke ICE, the ICE system 10 allows operation in lean conditions where it is not possible to obtain as much power per power cycle as a conventional diesel ICE. x The two-stroke cycle allows twice as many power cycles at the same ICE rpm, although hydrogen and other gases need to be kept lean for power control purposes.

[0162] In operation of the ICE system 10, the ICE system 10 may perform the following methods:

[0163] 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 uncovered, the effective power stroke ends and the gas is exhausted through the exhaust port. Subsequently, in step S20, the intake valve of one of the cylinders is opened and the cylinder is purged with intake air fed 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.

[0164] 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 is operated to inject, for example, hydrogen fuel. The hydrogen fuel is injected into the intake port, thereby generating a pressure pulse by the injected hydrogen fuel. Therefore, the ICE system 10 is operated to start injecting hydrogen into the air flow in the plenum 25, thereby feeding air and hydrogen into the cylinder. Just after the initial scavenging (cylinder purge), the intake valve opens, and then the injection begins, and the injection ends before the intake valve closes, thereby providing an intake port that is substantially free of combustible gas.

[0165] The initial scavenging (purge) of the cylinder is the time between IVO and the start of hydrogen injection.

[0166] In step S50, the piston continues to travel upward through the stroke (approximately halfway) and the intake valve closes.

[0167] In step S60 , the piston travels to just before TDC, TDC, or just after TDC (ie, close to TDC).

[0168] Subsequently, in step S70, an ignition source (eg, a spark plug) ignites the homogeneous air / hydrogen mixture in the cylinder.

[0169] Then, in step S80, the piston is forced downward (expanded) in a power stroke.

[0170] Thereafter, in step S90, the above steps S10 to S80 are cyclically repeated.

[0171] As can be easily understood from the above, the purge operation, the scavenging operation and the subsequent fuel injection operation produce a boost pulse, and the hydrogen (H2) / air mixture is pushed into the cylinder at the end of the 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 can avoid or at least reduce the risk of a hydrogen mixture in the plenum chamber 25, thereby reducing the risk of flashback.

[0172] It should be noted that if the intake valves are all open 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 gases, so that a low mixture between fresh charge air and hot exhaust gas combustibles is obtained. This may have the advantage of reducing the temperature of the mixture and the residues in the mixture preparation process. When the piston is halfway in the cylinder, the intake valve is completely closed, which reduces the risk of flashback.

[0173] 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 using, for example, the controller 90 .

[0174] The combustion chamber can be designed in several different ways and can be any of a flat design, a hemispherical design or a sloped roof design with only intake valves. It may be beneficial to cover a large area of ​​the combustion chamber with valves so that the cylinder can be filled in an efficient manner.

[0175] All moving parts in the ICE 20 can typically be lubricated by conventional pressure lubrication. Other options are also possible.

[0176] The positive displacement device 23 and plenum 25 of the intake duct 22 are generally considered cold parts and may be made of aluminum alloy. The intake duct 22 may generally be fastened to a cylinder head which may be hotter, and which is made of cast iron or steel. This may minimize the risk of hydrogen embrittlement, as no hydrogen-containing gas comes into contact with any iron or steel at a temperature below 150 degrees Celsius, which is the threshold at which hydrogen embrittlement is considered to occur.

[0177] The ICE system 10 can be cooled in several 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 combustibles (H2 produces H2O when burned). In addition, the ICE system 10 may include a water injection system. The water injection system can 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, it is beneficial to mix and evaporate / cool 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.

[0178] It should be noted that the ICE system 10 may not be limited to systems having a single 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 equally possible.

[0179] In an ICE system 10 that further includes additional pairs of adjacent cylinders, each arrangement of a pair of adjacent cylinders has a corresponding intake duct with a corresponding positive displacement device.

[0180] 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, each of which is arranged to cooperate with a given pair of cylinders. In this arrangement, the flow of fluid (air) to each pair of cylinders should be separated from each other. The cylinder pairs can be spaced apart to allow the fuel to be ignited in three cylinders at a time (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 causing unwanted pulsations because one cylinder is on its intake stroke while the other is on its power stroke.

[0181] Furthermore, the present disclosure may be illustrated by any of the following examples.

[0182] Example 1: A spark ignition internal combustion engine ICE system 10 for a vehicle, comprising: a two-stroke ICE 20 capable of operating with a gaseous fuel or a liquid fuel 50, the ICE having at least one pair of first cylinders 30 and second cylinders 40, the first cylinders and second cylinders having corresponding first cylinder walls 30a and second cylinder walls 40a, the first cylinder accommodating a reciprocating first piston 31 capable of operating between a bottom dead center and a top dead center, and also at least partially defining a first combustion chamber 32 with a top end 33 of the first piston, wherein the first cylinder further comprises: an ignition source 34 arranged in the first combustion chamber, at least one intake port 3 arranged at a top end 36 of the first cylinder and in fluid communication with the combustion chamber 5, wherein the flow of the combustible gas through the at least one intake port can be controlled by an intake control valve 37, and the first cylinder also includes an exhaust port 38, the exhaust port is arranged on the far side of the top end of the first cylinder, so that when the first piston is at its top dead center, the at least one intake port and the exhaust port are located at different positions and separated by the piston top end, the second cylinder accommodates a reciprocating second piston 41 that can operate between the bottom dead center and the top dead center, and also at least partially defines a second combustion chamber 42 with the 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 in fluid communication with the second combustion chamber, wherein the flow of the combustible gas through the at least one corresponding intake port can be controlled by a corresponding intake control valve 47, and the second cylinder also includes a corresponding exhaust port 48, the corresponding exhaust port is arranged on the far side of the top end of the second cylinder, so that when the second piston is at its top dead center, the at least one corresponding intake port and the corresponding exhaust port are located Different positions and separated by the piston top, the pair of first cylinders and the second cylinder pair are arranged to be 180 crank angles apart from each other; and an intake duct 22, the intake duct includes a positive displacement device 23, the positive displacement device is configured to receive intake air and feed the intake air to the at least one pair of cylinders, the positive displacement device is also arranged in the intake duct to separate the upstream intake passage 24 of the intake duct from the downstream collecting chamber 25, the downstream collecting chamber is fluidically connected to each of the first cylinder and the second cylinder of the at least one pair of cylinders.

[0183] Example 2: The ICE system according to example 1, wherein the ICE system comprises a fuel injector device 26 arranged in the downstream plenum of the intake duct to provide fuel injection upstream of the intake ports of the first cylinder and the second cylinder.

[0184] Example 3: An ICE system according to Example 2, wherein the fuel injector device is controllable in response to a fuel injection event so that fuel injection is injected into the intake port and the corresponding intake port so that a pressure pulse is generated in the plenum and then travels into the corresponding combustion chamber.

[0185] Example 4: An ICE system according to any one of Examples 2 and 3, wherein the fuel injector device is capable of being controlled to provide sequential fuel injection to the first cylinder and the second cylinder to allow active cylinder scavenging during the rear portion of the corresponding intake stroke of the corresponding cylinder in the first cylinder and the second cylinder.

[0186] Example 5: An ICE system according to any of the preceding examples, wherein the intake control valve of the first cylinder is controllable according to the movement of the first piston, and the intake control valve of the second cylinder is controllable according to the movement of the second piston, so that the fluid connection between the corresponding combustion chamber and the downstream plenum chamber is selectively opened and closed during rotation of the crankshaft of the ICE.

[0187] Example 6: The ICE system of any of the preceding examples, 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 and second cylinders.

[0188] Example 7: An ICE system according to any of the preceding examples, wherein the intake control valve is configured to provide variable valve actuation.

[0189] Example 8: An ICE system according to any of the preceding examples, wherein the positive displacement device is a variable positive displacement device configured to operate in a variable manner.

[0190] Example 9: An ICE system according to any of the preceding examples, wherein the exhaust port is arranged in fluid communication with an exhaust duct 61 arranged to convey exhaust gas away from the cylinder.

[0191] Example 10: An ICE system according to any of the preceding examples, further comprising a turbocharger device 70 having a turbocharger turbine 71 operably connected to a turbocharger compressor 72, wherein the turbocharger compressor is arranged in an intake duct 73 leading to the intake duct, wherein the turbocharger turbine is arranged in the exhaust duct so as to drive the turbocharger compressor.

[0192] Example 11: An ICE system according to any of the preceding examples, further comprising an exhaust gas recirculation (EGR) system 80, the EGR system comprising an EGR conduit 81 arranged to connect the exhaust duct 61 and the intake duct 22 so as to allow exhaust gas to recirculate through the cylinders during operation of the ICE.

[0193] Example 12: The ICE system of Example 11, wherein the EGR system further comprises a corresponding positive displacement device 82 .

[0194] Example 13: The ICE system of Example 12 or Example 13, wherein the EGR conduit is connected to the intake conduit at a location 84 downstream of the turbocharger compressor and further connected to the exhaust conduit at a location 85 upstream of the turbocharger turbine.

[0195] Example 14: 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.

[0196] Example 15: An ICE system according to any of the preceding examples, wherein the ICE system is configured to collectively control the positive displacement device and the intake valve to control the flow of gas to the combustion chamber.

[0197] Example 16: An ICE system according to Example 15, wherein the ICE system is configured to terminate fuel injection during the intake phase and before intake valve closing, so that the remainder of the intake phase includes purging the fuel in the plenum and then introducing fresh air into the plenum by operating the positive displacement device.

[0198] Example 17: An ICE system according to any of the preceding examples, wherein the ICE system comprises a set of a plurality of cylinder pairs having corresponding intake ducts with corresponding positive displacement devices.

[0199] Example 18: A vehicle comprising an internal combustion engine system according to any one of Examples 1 to 17.

[0200] 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.

[0201] 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.

[0202] The terms used herein are only for the purpose of describing specific aspects and are not intended to limit the present disclosure. As used herein, unless the context clearly indicates otherwise, the singular forms "one" and "said" are intended to include plural forms as well. 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" and / or "comprising" when used herein indicate 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.

[0203] It should be understood that although the terms first, second, etc. can be used to describe various elements in this article, 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, the first element can be referred to as the second element, and similarly, the second element can be referred to as the first element.

[0204] 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 will 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 intervening elements. In contrast, when an element is referred to as being "directly connected" or "directly coupled" to another element, there are no intervening elements.

[0205] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by those of ordinary skill 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.

[0206] 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 disclosure is set forth in the appended claims.

Claims

1. A spark-ignition internal combustion engine (ICE) system (10) for a vehicle, the spark-ignition ICE system comprising: - a two-stroke ICE (20) capable of operating on gaseous fuel or liquid fuel, the two-stroke ICE having at least one pair of first and second cylinders (30, 40), the at least one pair of first and second cylinders having corresponding first and second cylinder walls (30a, 40a), ○ The first cylinder accommodates a reciprocating first piston (31) capable of operating between a bottom dead center and a top dead center, and also at least partially defines a first combustion chamber (32) with a top end (33) of the first piston, wherein the first cylinder also includes an ignition source (34) arranged in the first combustion chamber, at least one intake port (35) arranged at the top end (36) of the first cylinder and connected to the first combustion chamber fluid, wherein the flow of combustible gas through the at least one intake port can be controlled by an intake control valve (37), and the first cylinder also includes an exhaust port (38), the exhaust port is arranged on the far side of the top end of the first cylinder, so that when the first piston is at its top dead center, the at least one intake port and the exhaust port are located at different positions and are separated by the top end of the first piston, ○ The second cylinder accommodates a reciprocating second piston (41) capable of operating between a bottom dead center and a top dead center, and also at least partially defines a second combustion chamber (42) with the 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, wherein the flow of combustible gas through the at least one corresponding intake port can be controlled by a corresponding intake control valve (47), and the second cylinder also includes a corresponding exhaust port (48), the corresponding exhaust port is arranged on the far side of the top end of the second cylinder, so that when the second piston is at its top dead center, the at least one corresponding intake port and the corresponding exhaust port are located at different positions and separated by the top end of the second piston, - the pair of first cylinder and second cylinder are arranged to be spaced apart from each other by 180 crank angle degrees; and - an intake duct (22), the intake duct comprising a positive displacement device (23), the positive displacement device being configured to receive intake air and feed the intake air to the at least one pair of first and second cylinders, the positive displacement device being further arranged in the intake duct to separate an upstream intake passage (24) from a downstream plenum (25) of the intake duct, the downstream plenum being in fluid communication with each of the first cylinder and the second cylinder of the at least one pair of first and second cylinders.

2. The ICE system according to claim 1, wherein the ICE system comprises a fuel injector device (26) arranged in the downstream plenum of the intake duct so as to provide fuel injection upstream of the intake ports of the first cylinder and the second cylinder.

3. The ICE system of claim 2, wherein the fuel injector arrangement is controllable to provide sequential fuel injection to the first cylinder and the second cylinder so as to allow active cylinder scavenging during a rear portion of a corresponding intake stroke of a corresponding one of the first cylinder and the second cylinder.

4. An ICE system according to any one of the preceding claims, wherein the intake control valve of the first cylinder is controllable according to the movement of the first piston, and the corresponding intake control valve of the second cylinder is controllable according to the movement of the second piston, so that the fluid communication between the corresponding first and second combustion chambers and the downstream plenum chamber is selectively opened and closed during rotation of the crankshaft of the ICE.

5. The ICE system of any one of the preceding claims, wherein the plenum comprises 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 and second cylinders.

6. An ICE system according to any preceding claim, wherein the positive displacement device is a variable positive displacement device configured to operate in a variably manner.

7. An ICE system according to any one of the preceding claims, further comprising a turbocharger device (70), the turbocharger device having a turbocharger turbine (71) operatively connected to a turbocharger compressor (72), wherein the turbocharger compressor is arranged in an intake duct (73) leading to the intake duct, and wherein the turbocharger turbine is arranged in the exhaust duct (61) so as to drive the turbocharger compressor.

8. An ICE system according to any one of the preceding claims, further comprising an exhaust gas recirculation (EGR) system (80), the EGR system comprising an EGR conduit (81) arranged to connect the exhaust duct and the intake duct so as to allow exhaust gas to recirculate through the cylinders during operation of the ICE.

9. The ICE system of claim 8, wherein the EGR system further comprises a corresponding positive displacement device (82).

10. An ICE system according to claim 8 or claim 9, when dependent on claim 7, wherein the EGR conduit is connected to the intake conduit at a position (84) downstream of the turbocharger compressor and further connected to the exhaust duct at a position (85) upstream of the turbocharger turbine.

11. An ICE system according to any one of the preceding claims, wherein the ICE system is a hydrogen ICE system configured to operate on a gaseous fuel comprising a hydrogen-based gaseous fuel.

12. An ICE system according to any one of the preceding claims, wherein the ICE system is configured to collectively control the positive displacement device and the intake valve to control the flow of gas to the first combustion chamber and the second combustion chamber.

13. An ICE system according to any one of the preceding claims, wherein the ICE system is configured to terminate fuel injection during the intake phase and before intake valve closing, whereby the remainder of the intake phase comprises purging the plenum of fuel and subsequently introducing fresh air into the plenum by operating the positive displacement device.

14. An ICE system according to any preceding claim, wherein the ICE system comprises a set of a plurality of cylinder pairs having corresponding intake ducts with corresponding positive displacement devices.

15. A vehicle comprising an internal combustion engine system according to any one of claims 1 to 14.

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