Engine braking and air charging system for hydrogen internal combustion engines

Abstract

An intake system for an internal combustion engine and a method of operating the intake system. The system includes: a turbocharger; a supercharger connected in series with the turbocharger; a first intercooler between the turbocharger and the supercharger; and a second intercooler downstream of the supercharger. The method includes: operating the intake system to support the internal combustion engine in a drive mode by opening a first throttle valve in a first bypass line, bypassing the supercharger; and operating the intake system to support the internal combustion engine in a braking mode by closing the first throttle valve in the first bypass line.

Description

[0001] Cross-citation of related applications

[0002] This application claims priority to the following applications: U.S. Provisional Patent Application Serial No. 63 / 623,008, filed January 19, 2024; U.S. Provisional Patent Application Serial No. 63 / 603,993, filed November 29, 2023; U.S. Patent Application Serial No. 18 / 732,382, filed June 3, 2024; and Indian Provisional Patent Application Serial No. 202411064169, filed August 26, 2024, the entire contents of which are incorporated herein by reference. Background Technology

[0003] Traditional engine braking systems focus on precise control of engine operation to achieve effective braking. These systems typically employ a compression-release brake, which releases pressure in the cylinder during the compression stroke, creating resistance and slowing the engine. Additionally, the system may involve a throttle shut-off device to further reduce power. Integrated with the transmission (whether manual or automatic), optimized gear selection enhances braking performance. The overall design considers a balance between braking performance, fuel efficiency, noise control, and emissions compliance to provide an effective engine braking solution.

[0004] Traditional superchargers are typically driven by the engine crankshaft via a belt drive system, and can therefore be considered active devices. In some applications, the supercharger is coupled with a clutch to selectively activate it when continuous operation is not always required. This type of air supercharging system has capacity limitations and is not well-suited for certain applications. Improvements are needed. Summary of the Invention

[0005] Currently, vehicles with internal combustion engines (ICE) typically have a compression ratio of approximately 18:1 and a matching braking power, which is necessary for safe and effective braking in many ICE-powered vehicles. Hydrogen ICE (H2 ICE) has a reduced compression ratio of approximately 12:1 or 11:1 to prevent autoignition. H2 ICE is able to match the propulsion power of a conventional engine with this reduced compression ratio, but braking power is significantly reduced, by approximately 25-30%. As disclosed herein, pressurizing the air in the cylinders during braking operations increases the available braking power.

[0006] Automotive applications with high air pressure requirements (such as hydrogen internal combustion engines) may require multi-stage air supercharging structures instead of the current conventional single-stage supercharging. Different structures can be followed to meet these high airflow requirements. Examples include turbocharger-supercharger combinations, supercharger-turbocharger combinations, and / or two-stage turbochargers. In the case of turbocharger-supercharger and supercharger-turbocharger combinations, the supercharger can be used for low-speed, high-load conditions and transient operation, where the turbocharger alone cannot provide the required performance and eliminate turbo lag. It should also be noted that any additional supercharging devices incorporated to achieve high λ (2.0–2.5) should also maximize engine efficiency and minimize engine NOx output.

[0007] The example presented herein relates to an intake system for an internal combustion engine. The system includes: a turbocharger; a supercharger connected in series with the turbocharger; a first intercooler located between the turbocharger and the supercharger; and a second intercooler located downstream of the supercharger.

[0008] In some instances, the second intercooler has an outlet temperature of less than or equal to 50°C, more preferably less than or equal to 40°C, and even more preferably less than or equal to 30°C. In some instances, the first intercooler has an outlet temperature of less than or equal to 50°C, more preferably less than or equal to 40°C, and even more preferably less than or equal to 30°C.

[0009] In some instances, the system also includes a first bypass line that diverts flow around the turbocharger during drive operation. In some instances, the first bypass line diverts flow from the turbocharger inlet to the inlet of the second intercooler. In some instances, the system also includes a first throttle valve in the first bypass line.

[0010] In some instances, the system also includes a second bypass line that provides additional flow to the inlet of the turbocharger during braking. In some instances, the second bypass line diverts flow from the outlet of the second intercooler to the inlet of the turbocharger. In some instances, the system also includes a first bypass line that diverts flow around the turbocharger during drive operation, wherein the diameter of the first bypass line is larger than the diameter of the second bypass line. In some instances, the second bypass line is a rubber hose. In some instances, the system also includes a second throttle valve in the second bypass line.

[0011] In some instances, the turbocharger is a clutch-type turbocharger. In some instances, the clutch-type turbocharger includes an integrally formed clutch. In some instances, the system also includes an acceleration device connected to the clutch-type turbocharger.

[0012] In some instances, the supercharger is a pulley-driven supercharger, a gear-driven supercharger, or an electric motor-driven supercharger. In some instances, the supercharger is an electric motor-driven supercharger, and the supercharger is a two-speed supercharger.

[0013] In some instances, the second intercooler discharges gases into the intake manifold of the hydrogen internal combustion engine.

[0014] The examples presented herein relate to a method of operating an intake system for an internal combustion engine, the intake system including a turbocharger, a first intercooler, a supercharger, and a second intercooler connected in series. The method includes: bypassing the supercharger by opening a first throttle valve in a first bypass line to operate the intake system to support the internal combustion engine in a drive mode; and operating the intake system to support the internal combustion engine in a braking mode by closing the first throttle valve in the first bypass line.

[0015] In some instances, operating the intake system to support an internal combustion engine in braking mode also includes directing airflow from the outlet of the second intercooler to the inlet of the turbocharger by opening a second throttle valve in a second bypass line.

[0016] In some instances, the turbocharger is a clutch-type turbocharger. In some instances, operating the intake system to support the internal combustion engine in drive mode further includes: operating the clutch to disengage the turbocharger. In some instances, operating the intake system to support the internal combustion engine in braking mode further includes: operating the clutch to connect the turbocharger to an acceleration device. In some instances, the turbocharger is an electric motor-driven turbocharger, wherein the electric motor has at least two speeds; wherein operating the intake system to support the internal combustion engine in drive mode further includes: operating the electric motor at a first speed; and wherein operating the intake system to support the internal combustion engine in braking mode further includes: operating the electric motor at a second speed, wherein the second speed is greater than the first speed.

[0017] In some instances, the internal combustion engine is a hydrogen internal combustion engine.

[0018] The example given here relates to an intake system for an internal combustion engine, the intake system including a turbocharger, a first intercooler, a supercharger and a second intercooler arranged in series in an engine compartment, such that: the first intercooler is located at the rear boundary of the engine compartment; the second intercooler is located in front of the first intercooler; and both the turbocharger and the supercharger are located in front of the second intercooler.

[0019] In some instances, the system includes a turbocharger bypass line positioned between the second intercooler and the turbocharger. In some instances, the second intercooler is larger than the first intercooler.

[0020] Several other aspects of the invention will be set forth in the following description. These aspects may involve individual features and combinations thereof. It should be understood that the foregoing description and the following detailed description are merely exemplary and explanatory, and do not limit the broad inventive concept upon which the embodiments disclosed herein are based. Attached Figure Description

[0021] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate several aspects of this disclosure. A brief description of the drawings follows: Figure 1 This is the typical processing flow of a four-stroke internal combustion engine (ICE) cycle during engine braking.

[0022] Figure 2 It is a graph depicting a typical decompression braking lift curve.

[0023] Figure 3A It is a graph depicting the decompression braking lift curve used in a two-stroke braking cycle.

[0024] Figure 3B It is a graph depicting another decompression braking lift curve used in a two-stroke braking cycle.

[0025] Figure 4A This is a flowchart of an exemplary method for increasing the braking power of a decompression braking cycle.

[0026] Figure 4B This is a flowchart of another exemplary method for increasing the braking power of the decompression braking cycle.

[0027] Figure 5 These are exemplary engines and decompression braking systems.

[0028] Figure 6A This is an exemplary turbocharger device in an engine.

[0029] Figure 6B It can be connected to and Figure 6A An example of a dry clutch for a drive belt associated with a supercharger is shown.

[0030] Figure 6C yes Figure 6A The example shown is a supercharger equipped with an integrally formed magnetic clutch.

[0031] Figure 6D yes Figure 6A The example shown is a supercharger equipped with a drive belt that is connected to a multi-disc clutch.

[0032] Figure 6E Is it possible to... Figure 6A The example shown is a three-way clutch that is either connected to or integrally formed with a turbocharger.

[0033] Figures 7A to 7C It shows the method for increasing Figures 6A to 6B An example of the pressure ratio across the booster is shown.

[0034] Figure 7D A power graph is shown demonstrating the effectiveness of increasing the pressure ratio to increase the load applied by the booster.

[0035] Figure 8 This is a block diagram of an exemplary computer system on which the systems and methods of various aspects of this disclosure can be operated.

[0036] Figure 9 This is a schematic diagram illustrating a prior art air booster system.

[0037] Figure 10 This is a schematic diagram showing a hydrogen-based internal combustion engine and related intake and exhaust systems having features according to the present invention; Figure 11 It shows that it can be used with Figure 10 The diagram shows a turbocharger-turbocharger air booster system used in conjunction with an internal combustion engine.

[0038] Figure 12 It shows that it can be used with Figure 10 The diagram shows a turbocharger-turbocharger air booster system used in conjunction with an internal combustion engine.

[0039] Figure 13 It shows that it can be used with Figure 10 The diagram shows a turbocharger-turbocharger air booster system used in conjunction with an internal combustion engine.

[0040] Figure 14 It shows that it can be used with Figure 10 The diagram shows a turbocharger-turbocharger air booster system used in conjunction with an internal combustion engine.

[0041] Figure 15 It shows that it can be used with Figure 10 The diagram shows a turbocharger-turbocharger air booster system used in conjunction with an internal combustion engine.

[0042] Figure 16 It shows that it can be used with Figure 10 The diagram shows a turbocharger-turbocharger air booster system used in conjunction with an internal combustion engine.

[0043] Figure 17 It shows that it can be used with Figure 10 The diagram shows a turbocharger-turbocharger air booster system used in conjunction with an internal combustion engine.

[0044] Figure 18This is a summary table of the structural details of the various embodiments disclosed herein.

[0045] Figure 19A Is with Figure 14 The diagram shows the efficiency of the air booster system.

[0046] Figure 19B Is with Figure 13 The diagram shows the efficiency of the air booster system.

[0047] Figure 20 It is a graph showing a comparison of braking efficiency and braking power between clutch-type and non-clutch-type air booster system configurations.

[0048] Figure 21 yes Figure 10 The use shown in Figure 15 A schematic top view of an internal combustion engine with an air-charging system.

[0049] Figure 22 for Figure 21 The diagram shows a schematic end view of the internal combustion engine and air supercharging system.

[0050] Figure 23 This is a schematic diagram of the combustion and braking combined system structure.

[0051] Figure 24 yes Figure 23 A schematic diagram of alternative structural configurations for the combustion and braking combined system.

[0052] Figure 25 This is a schematic diagram of a combustion and braking combined system using a dual-valve structure.

[0053] Figure 26 yes Figure 25 A schematic diagram of alternative structural configurations for the combustion and braking combined system.

[0054] Figure 27 yes Figure 25 A schematic diagram of alternative structural configurations for the combustion and braking combined system.

[0055] Figure 28 These are a pair of graphs showing the effect of the acceleration device on braking power and boost power.

[0056] Figure 29 It is an efficiency graph related to the acceleration device.

[0057] Figure 30 This is a schematic diagram of a braking acceleration device that disconnects the supercharger during braking.

[0058] Figure 31AIt is a graph showing the braking performance without an acceleration device.

[0059] Figure 31B It is a graph showing the braking performance using the acceleration device.

[0060] Figure 32 This is an efficiency graph related to disconnecting the turbocharger during braking.

[0061] Figure 33 It is an exhaust gas recirculation structure without an acceleration device.

[0062] Figure 34 It is an exhaust gas recirculation structure with an acceleration device.

[0063] Figure 35 It is an exemplary exhaust gas recirculation structure with a turbocharger disconnect device. Figure 36 This is another example of an exhaust gas recirculation structure with a turbocharger disconnect device. Detailed Implementation

[0064] Reference will now be made in detail to exemplary aspects of this disclosure as illustrated in the accompanying drawings. Wherever possible, the same reference numerals will be used throughout the drawings to refer to the same or similar parts.

[0065] Hydrogen internal combustion engines (H2 ICE) represent a class of internal combustion engines that use hydrogen as a fuel source instead of traditional hydrocarbon-based fuels such as gasoline or diesel. These engines operate on the same basic principles as conventional internal combustion engines, but have some key differences in fuel characteristics and combustion features.

[0066] Gaseous hydrogen is commonly used as a primary fuel. Hydrogen is considered a clean fuel because its combustion produces only water vapor and heat, making it an environmentally friendly alternative. Engine designs are modified to accommodate the unique properties of hydrogen, such as its wider range of combustibility and higher flame speed.

[0067] The combustion process in a hydrogen internal combustion engine involves the mixing of hydrogen with air in the engine cylinders. The unique combustion characteristics of hydrogen allow for flexibility in the design of hydrogen-powered engines. Hydrogen engines can typically operate at higher compression ratios to take advantage of hydrogen's high octane rating. However, unlike conventional hydrocarbon fuels such as diesel, hydrogen does not suffer from the same problems as pre-ignition or knocking. Therefore, hydrogen engines are also able to operate efficiently at lower compression ratios compared to diesel engines. This lower compression ratio can be advantageous for certain hydrogen engine designs.

[0068] In some cases, H2 ICEs are configured with lower compression ratios to prevent autoignition of hydrogen fuel. Lower compression ratios can also be advantageous in reducing mechanical stress on engine components and potentially simplifying the overall engine design. Hydrogen combustion tends to produce lower levels of nitrogen oxides (NOx), a major cause of air pollution. The lower compression ratio in hydrogen engines can also help reduce NOx emissions compared to diesel engines. This lower compression ratio can further impact the materials used in the engine structure. Engine components need to be designed to handle the specific requirements of hydrogen combustion, and a lower compression ratio can affect the total stress on these materials. In some implementations of H2 ICEs, a reduced compression ratio may be necessary for efficient operation. For example, in spark-ignition H2 ICEs, combustion may require a lower compression ratio.

[0069] While lowering the compression ratio offers advantages such as increased tolerance to lower octane fuels, smoother operation, and reduced knocking tendency, its effects require additional design considerations in certain areas of engine operation. During engine braking, the reduced compression ratio decreases the available braking power during engine braking operations. When there is no fuel supply (as in braking situations), the available cylinder pressure, which determines the available braking power, is driven by the compression ratio. Therefore, the potential power of an engine braking event decreases as the compression ratio decreases.

[0070] Methods and systems for improving engine braking power are disclosed herein. In one embodiment, an air compressor, such as a turbocharger, increases the pressure in the cylinder during an intake event, resulting in greater braking power as the piston approaches top dead center (TDC) and the exhaust valve opens for braking. In another embodiment, an increase in pressure is provided as the piston approaches bottom dead center (BDC). The disclosed systems and methods can provide specific advantages for braking H2 ICE engines, and even more specific advantages for H2 ICE engines with low compression ratios; however, the principles of this disclosure are applicable to and effective for a wide range of engines.

[0071] While this disclosure focuses on using an air compressor to increase braking power, it should be noted that the use of such a compressor (e.g., a turbocharger) can have additional advantages in the operation of H2 ICE. For example, incorporating a turbocharger can improve the efficiency of an H2 ICE operating at a high λ (lambda). In the context of internal combustion engines, the term "λ" refers to the air-fuel ratio, precisely the ratio of the actual air-fuel mixture to the stoichiometric air-fuel ratio. The stoichiometric ratio is the chemically ideal ratio for complete combustion. A λ value of 1.0 corresponds to a stoichiometric air-fuel ratio. When an engine operates at a λ greater than 1.0, this means that there is an excess of air in the mixture compared to the stoichiometric ratio. This condition is commonly referred to as "lean" operation. In a lean-burn mixture, the combustion temperature tends to be higher, which can affect engine performance and emissions. Lean-burn engines are often equipped with technologies such as exhaust gas recirculation (EGR) or catalytic converters to mitigate the impact on emissions.

[0072] Embodiments of this disclosure include systems configured to have a lower limit of 2.4λ. For example, the system configuration disclosed herein uses a booster to provide sufficient air delivery to the lower limit of 2.4λ. This configuration can be particularly advantageous during transient operation and high-load, low-speed operation.

[0073] See now Figure 1 This diagram illustrates the typical four-stroke ICE cycle processing flow 100 during engine braking. The process occurs in cylinder 102 via the operation of piston 104, intake valve 106, and exhaust valve 108. During the intake stroke 110, air is drawn into cylinder 102 through intake valve 106 as piston 104 is drawn out. During the compression stroke 112, work is performed to compress the air in cylinder 102 as piston 104 moves toward the top of cylinder 102. During compression release 114, unlike during engine drive operation where fuel to be burned is added to the cylinder, no fuel is added to cylinder 102, and pressure is released through exhaust valve 108. During the power stroke 116, piston 104 is drawn out again, but without expansion and without the positive force generated after the combustion event. During the exhaust stroke 118, the remaining air in cylinder 102 is expelled through exhaust valve 108.

[0074] See now Figure 2 This shows graph 200 depicting a typical decompression braking lift curve. Intake event 202 (which can correspond to...) Figure 1The intake stroke 110 occurs after the first piston stroke 204, at which point air is drawn into the cylinder. During intake event 202, the piston moves downward in the cylinder, creating a vacuum that allows the intake valves to open. When the piston reaches bottom dead center (BDC), air is drawn into the cylinder. BDC refers to the piston's position in the internal combustion engine at the lowest point of its stroke in the cylinder during the engine's four-stroke cycle.

[0075] Around the end of intake event 202, but before the second piston stroke 208, brake gas recirculation (BGR) event 206 occurs. The BGR event can be accomplished by opening the exhaust or auxiliary valve near the BDC during the piston's intake or expansion stroke and keeping the exhaust or auxiliary valve open during the first portion of the engine's exhaust or compression stroke. Opening the exhaust or auxiliary valve during this portion of the engine recirculation allows exhaust gas to flow from the relatively high-pressure exhaust manifold into the engine cylinders. Introducing exhaust gas from the exhaust manifold into the cylinders allows for faster cylinder pressurization than would occur during the compression stroke. The increased gas pressure in the engine cylinders can increase the braking power generated by the subsequent compression release event.

[0076] Compression release (CR) event 210 may occur just before or together with the second piston stroke 208, which may be related to the power stroke (such as...) Figure 1 The power stroke 116 is associated with this. During CR event 210, some pressure from the cylinder can be released, for example, through the exhaust valve. The opening of this exhaust valve releases compressed air from the cylinder into the exhaust system, bypassing the actual power stroke that would be driven by combustion of fuel in the cylinder. Without combustion in the affected cylinder, there is no power stroke to drive the engine. Because the engine acts as an air pump, this lack of power stroke produces a braking effect, absorbing energy from the vehicle's motion as the piston retracts from top dead center (TDC). TDC is the position where the piston reaches its highest point in the cylinder during the compression stroke. At TDC, the piston is temporarily stationary before it begins to move downwards again during the power stroke. Exhaust event 212 ends the decompression braking lift curve when the remaining air in the cylinder is released through the exhaust valve.

[0077] As disclosed herein, a boost event 214 is added to the braking cycle and additional air is introduced into the cylinder during intake event 202. In embodiments, boost event 214 may occur at the BDC (Body Control Center). Air can be supplied for boost event 214 from an air compressor (e.g., a turbocharger) integrally formed with the ICE. In addition to providing additional braking power by increasing the pressure within the cylinder to be released, the air compressor may also impose a parasitic load on the engine, which increases the total braking load. This load varies depending on the configuration of the compressor and the engine and can be significant in embodiments, such as up to 20 kW, up to 25 kW, up to 50 kW, up to 60 kW, up to 70 kW, up to 80 kW, or greater, in different embodiments. In some instances, the air compressor includes a turbocharger connected in series with the turbocharger, and in some instances, a turbocharger is included downstream of the turbocharger.

[0078] In some embodiments, the inclusion of boost event 214 is associated with the removal or elimination of BGR event 206 because boost event provides a more effective pressure increase than BGR event. Since the air supplied from the air compressor is not, for example, the hot exhaust gas supplied during a BGR event, it has a greater density and therefore provides greater power than the exhaust gas supplied during a BGR event. Furthermore, in some instances, BGR event can effectively reduce braking power by providing an alternative escape path for the boosted air in the cylinder. In several embodiments, eliminating BGR event may be preferred due to further advantages, such as simplification of the valve mechanism.

[0079] Increasing the pressure in the cylinders during an intake event increases the braking power available during the engine braking cycle. This is because the engine essentially acts as an air pump, releasing compressed air to produce a braking effect, thereby absorbing energy from the vehicle's motion, and releasing greater pressure to cause greater braking power. Furthermore, increasing the air supply from the air compressor during a boost event allows for a reduction in one or both of the intake stroke's height and duration. In some cases, such as if a simplified valve mechanism is preferred, the intake stroke may not change from its standard stroke.

[0080] See now Figure 3A A graph 300 depicting the decompression braking lift curve of a two-stroke braking cycle is shown. This engine braking lift curve uses four strokes of the engine cycle to achieve two two-stroke braking cycles. Four-stroke intake event 202 and exhaust event 214 are also shown for reference.

[0081] The first and second intake events 302 and 304 are each associated with the first and second BGR events 306 and 308, and the first and second CR events 310 and 312, respectively. Thus, an additional CR event with associated braking power is applied during each engine cycle. According to this disclosure, each intake event 302 and 304 can also be associated with SC events 314 and 316 to increase the braking power of each braking event. The addition of boost events 314 and 316 as disclosed herein... Figure 3A The two-stroke cycle shown can be particularly advantageous. By combining the boosting event, the additional braking event provided in the two-stroke braking can be used without losing the power of each braking event, and without the power loss associated with each braking event.

[0082] See now Figure 3B A graph 350 is shown depicting another decompression braking lift curve of a two-stroke braking cycle. In the embodiment shown in graph 350, the intake stroke is modified to reduce the stroke height and / or duration by adding air to the cylinder at the BDC (180 degrees and 540 degrees in this example). The SC events 318 and 320 of this example are shown at the BDC and can be consistent with the BGR events 306 and 308 of conventional two-stroke braking. Therefore, the BGR events can be eliminated and replaced by SC events 318 and 320 to improve braking performance. In some applications, eliminating the BGR events is advantageous to eliminate a possible leakage path formed through the exhaust pipe, through which air supplied from the cylinder via the intake port could escape. Due to the increased power provided by the SC events, the overall intake events may not need to be large enough to achieve the desired braking power.

[0083] See now Figure 4A and Figure 4B A flowchart of an example method 400 for increasing braking power in a decompression braking cycle is shown. In an embodiment, method 400 may be executed by a system controller that operates or directs the operation of one or more components of the engine. In an embodiment, the controller includes a propulsion mode and a braking mode. Each mode may be associated with specific operations and parameters. Method 400 may form part of braking mode operation.

[0084] At operation 402, the piston retracts from the cylinder head, and an intake event occurs. At operation 404, a boost event is performed during the intake phase, and compressed air is added to the cylinder from the air compressor. In this embodiment, the boost event is performed when the piston is in the BDC (Breakdown Control) phase. In this embodiment, the boost event may occur in conjunction with a BGR (Breakdown Reduction) event, or a BGR event may not occur during the entire decompression braking cycle. At operation 406, the piston moves toward the top of the cylinder, and a compression event occurs to compress the air in the cylinder since there is no fuel. At operation 408, compressed air is released from the cylinder during a compression release event.

[0085] When the piston is retracted after the compression release event, the power stroke 411 can occur without expansion or positive force, as in a standard decompression braking cycle. Then, any remaining air in the cylinder is expelled during the engine's standard exhaust stroke 413 before the start of another intake stroke.

[0086] In an embodiment using a two-stroke engine braking cycle, an additional braking-only intake event occurs at operation 410 when the piston is retracted after compression release event 408. At operation 412, a boost event is applied and air is added to the additional intake event. At operation 414, an additional compression event compresses the air in the cylinder as the piston moves toward the top of the cylinder (which would be the exhaust stroke in a standard braking cycle). At operation 416, an additional compression release event occurs, and the piston can be retracted to begin the next cycle.

[0087] See now Figure 5 An exemplary engine and depressurization braking system are illustrated. Associated with depressurization brake 456, air compressor 600 (e.g., a supercharger) supplies air at the engine intake port to increase cylinder pressure during intake events. Controller 500 provides operating commands and / or control to the entire engine and / or braking system or components of the system. In embodiments, controller 500 may perform all operations described herein, including braking operations, such as those referenced above. Figure 4A and Figure 4B The method discussed is 400. The controller 500 can be configured as an electronic vehicle controller, such as... Figure 8 The controller is 500. Figure 5 Optional transmission system reducer 454 and pressure relief brake 456 are also shown, which can also be used in conjunction with the concepts disclosed herein. Transmission system reducer 454, pressure relief brake 456, and exhaust brake 457 are well known to those skilled in the art and do not need to be described further herein.

[0088] Exemplary turbocharger 600

[0089] See now Figures 6A to 6EAn exemplary arrangement of a supercharger 600 and its aspects are given. Figure 6A In the diagram, a supercharger 600 is shown mounted in a power unit 700. In the illustrated example, the power unit 700 is an internal combustion engine 700 configured to operate using hydrogen as a fuel source. As shown, the power unit 700 has an accessory or drive pulley 702 and one or more belts 704 operatively connecting the pulley 702 to a corresponding pulley 602 associated with the supercharger 600.

[0090] In one aspect, the booster 600 can be a fixed-displacement booster, such as a Roots-type or twin-scroll (TVS) booster, which outputs a fixed volume of air per rotation. Unlike some devices that change the volume of the working fluid when the fluid is sealed, the volume defined between the lobes and the housing of the booster is constant as the working fluid traverses the length of the rotor. Therefore, this booster can be called a "volumetric device" because the sealed or partially sealed volume of the working fluid does not change. In some instances, the booster can also be called a Roots-type booster or a twin-scroll booster, such as the TVS-type booster manufactured by the applicant. These types of boosters differ from other types of devices in which the working fluid is significantly compressed as it travels through the device.

[0091] The increased air output is then pressurized as it is forced into the intake chamber. This intensifier is a positive displacement device and therefore does not depend on rotational speed to generate pressure. The intensifier is a pair of rotors 626, 628 ( Figure 6C The volume of air delivered during each rotation of the turbocharger 600 (as shown) is constant (i.e., does not change with speed). Therefore, the turbocharger 600 can generate pressure at low engine and rotor speeds (where the turbocharger is powered by the engine), indicating that the turbocharger acts as a pump, where compression of the air delivered by the turbocharger 600 occurs downstream of the turbocharger 600, i.e., by increasing the air mass in the boost chamber of the fixed-displacement engine. Alternatively, the turbocharger 600 can be configured as a centrifugal turbocharger, which compresses air as it passes through the turbocharger 600, but the compression and therefore the volume of air delivered to the throttle valve 24 and the air pressure in the compressor chamber depend on the compressor speed.

[0092] In one aspect, and as Figure 6CReferenced elsewhere, a first rotor 626 rotates on a first shaft and has multiple protrusions that mesh with multiple protrusions of a second rotor 628 via a set of meshing timing gears 634, 636. It should be understood that the meshing of rotors 626, 628 means that their protrusions engage with each other when rotors 626, 628 rotate. However, the protrusions of rotors 626, 628 do not contact each other. The second rotor 628 rotates on a second shaft driven by the set of meshing timing gears 634, 636. Specifically, the first gear 634 is mounted on the first shaft to rotate with the first rotor 626. The second gear 636 is mounted on the second shaft to rotate with the second rotor 628. The first gear 634 meshes with the second gear 636. One of the first and second shafts is directly or indirectly connected to (e.g., via a gear train) an input / output shaft 656, which is further connected to a pulley 602.

[0093] In this implementation, the clutch 800 provides selective engagement and disengagement of the turbocharger 600 from the engine. Figure 6B An example of clutch 800 is shown, wherein clutch 800 is configured as a dry clutch operatively engaged with one or more belts via pulley 802. A clutch with similar features is disclosed in International PCT Publication WO 2014 / 150265A2, entitled “Dual-ratio drive for a variable-speed hybrid electric supercharger assembly,” the entire contents of which are incorporated herein by reference. This control over the supercharging process allows for a more nuanced approach to the supercharger. For example, by disengaging the supercharger during normal driving conditions or low-load conditions, the clutch helps to save energy and improve overall efficiency. This deliberate disengagement also helps to improve fuel efficiency and reduce wear on engine components. In an embodiment, clutch 800 is a two-position clutch having a first engaged position and a second neutral position. A two-position clutch will typically provide a single ratio between the drive speed or crankshaft speed and the supercharger speed. Examples include clutch-type superchargers used in automotive gasoline applications, such as superchargers that engage with an integrally formed magnetic clutch only when needed. Example supercharger and clutch arrangements applicable to the principles described herein are shown and described in WO'265 publication.

[0094] The actuation of clutch 800 can be performed by a pneumatic or electric actuator (such as a linear actuator), for example, via command from an electronic control unit or manual operation. Clutch 800 can be arranged in association with the turbocharger depending on engine package requirements. For example, the clutch can be configured on a front-end accessory device, in the turbocharger assembly, or connected to the crankshaft, for example, via an engine flywheel or similar gear. Clutch 800 can be configured as a two-way clutch for engaging or disengaging (i.e., neutral), or as a three-way clutch for disengaging and engaging at a first gear ratio or a second gear ratio. In either configuration, clutch 800 can be referred to as a two-speed clutch having a first gear ratio and a second gear ratio.

[0095] Based on the above, other types of clutch systems can be used with clutch 800. For example, such as... Figure 6C As shown, the turbocharger 600 may be equipped with an integrally formed magnetic clutch 800. Other examples include clutch-type turbochargers for heavy-duty diesel applications, such as those using a wet multi-plate clutch, a wet double-cone clutch, or a dry clutch for drive belt engagement at the engine front accessory drive. Figure 6D This is an example of a drive belt connected to a wet multi-plate clutch. Figure 6E This is an example of a three-way clutch 800. The clutch 800 includes positions 852 and 856 for two gear ratios and a neutral position 854. In the first position 852, the actuator 858 moves to the left, which also moves the claw clutch gear 864 to the left to engage with gear 860. In the neutral position 854, the actuator 858 moves the claw clutch gear 864 between gears 860 and 862 and disengages it from these gears. In the second position 856, the actuator 858 moves to the right, similarly moving the claw clutch gear 864 to the right to engage with gear 862. In this embodiment, the two ratios are different ratios.

[0096] The controlled boost support performance adjustment provided by clutch 800 allows for the flexibility of manually engaging or disengaging the supercharger based on power or braking needs. Furthermore, clutch 800 extends the life of the supercharger and related components. By minimizing unnecessary strain during periods when boost is not necessary, the clutch contributes to the lifespan of these components. While not all supercharging systems include a clutch, their presence is a design choice that meets the specific performance and efficiency objectives for a given application.

[0097] In one implementation, additional braking power is obtained from the supercharger by operating it at a higher speed. For example, a dual-speed ratioing device combines a first ratio for boosting and a second ratio for braking. The ratioing device adjusts the relationship between input and output parameters. The ratioing device can be used to change the speed, torque, or direction of rotational motion to meet specific operational requirements. In another implementation, the ratioing device is coupled with a clutch associated with the supercharger, such as... Figure 6A The clutch 800. This ratioing device can be integrated, for example, into a pulley-driven clutch housing or into a gear output at the flywheel, for example, in a rear-engine mounting implementation.

[0098] When clutch 800 is configured as a three-way clutch as described above and / or in WO'265 disclosure, clutch 800 can provide a neutral or disengaged state, a first gear ratio for nominal operation, and a different second gear ratio for braking operation. Thus, clutch 800 integrally functions as a ratioing device for turbocharger 600. In some cases, the second gear ratio is a faster or higher gear ratio than the first gear ratio. In embodiments, neutral is used to disengage turbocharger 600 when the user does not need or desires turbocharger 600 operation. Disengaging turbocharger 600 when not desired helps reduce engine parasitic losses.

[0099] Method for increasing the pressure ratio across the turbocharger 600

[0100] In implementations, the braking load can be further increased to further enhance engine braking by increasing the power consumption of the turbocharger. For example, the system is configured to increase the turbocharger pressure ratio (e.g., outlet pressure / inlet pressure) by adding limiting devices such as operable valves and / or by further controlling the position and timing of the intake valves. On the outlet side, additional limiting increases the outlet pressure, and on the inlet side, it decreases the turbocharger inlet pressure, effectively increasing the pressure ratio across the turbocharger and increasing the power consumed. If the mass flow rate decreases, the power will still increase due to the lower inlet density while maintaining a constant turbocharger speed.

[0101] refer to Figures 7A to 7D This paper presents a method to increase the pressure ratio across the turbocharger 600 by increasing the back pressure or decreasing the inlet pressure. Increasing the pressure ratio across the turbocharger 600 increases the pumping losses of the turbocharger 600, which in turn generates additional braking power during engine braking through parasitic losses. One way to increase the pressure ratio across the turbocharger 600 is to provide a controllable valve or orifice located at the inlet or outlet of the turbocharger, such as... Figures 7A to 7C As shown in the example.

[0102] refer to Figure 7ASystem 10 is shown as including a power unit 700 configured as an internal combustion engine 700 for use with a hydrogen fuel source. The internal combustion engine 700 is shown as including the aforementioned accessory or turbocharger pulley 702 and drive belt 704, and is also shown as including an intake manifold 706. In one aspect, system 10 is also shown as including an airflow path 12 extending from the intake or filter device 20 to the intake side of the turbocharger 600. An air flow sensor 22 and a throttle valve 24 are shown disposed within the airflow path 12. System 10 is further shown as including an outlet airflow path 14 extending from the outlet of the turbocharger 600 to the intake manifold 706. An air-to-water cooler 26 is shown disposed within the outlet airflow path 14. A bypass airflow path 16 is also shown extending from the outlet side downstream of the air-to-water cooler 26 of the turbocharger 600 to the intake side at a location between the throttle valve 24 and the turbocharger 600. Bypass valve 28 is shown as being disposed within bypass path 16, as Figure 6A As shown. In some arrangements, bypass valve 28 may be configured as a three-way valve connecting airflow paths 14, 16 and operable to divert some or all of the flow from booster 600 to bypass path 16 or manifold 706. Airflow paths 12, 14, 16 may be formed by piping systems, hoses, conduits, internal passages of system components, and combinations thereof. For example, bypass airflow path 16 may be integrally formed into the booster housing or externally provided with conduits or hoses. Figure 7A The configuration shown executes the above-mentioned procedures when bypass valve 28 is in the closed position. Figures 2 to 4B The described engine braking process requires all air supplied to the intake manifold 706 to be delivered by the supercharger 600. With the clutch 800 configured as a two-speed clutch, the clutch 800 can be engaged in a high-speed gear ratio during braking, as described above. In some instances, additional resistance can be achieved by increasing the pressure ratio or pressure difference across the supercharger 600 by operating the position of the throttle valve 24 independently or in coordination with the bypass valve 28. In some instances, additional resistance can be achieved by generating back pressure for the supercharger 600 by operating the position and timing of the engine intake valves. These strategies can also be combined... Figure 7B and Figure 7C The example presented in the document demonstrates this. This configuration also allows the turbocharger to operate in a vacuum during cruise, which reduces the input power requirements.

[0103] refer to Figure 7BAn alternative configuration is shown, in which additional back pressure valves 30a, 30b are disposed in the outlet airflow path 14, and in which the clutch 800 is configured with two different gear ratios. Although two back pressure valves 30a, 30b are shown, more or fewer back pressure valves may be provided. In one aspect, back pressure valve 30a is shown located between the supercharger 600 and the bypass path 16, while back pressure valve 30b is shown located between the manifold 706 and the bypass path 16. Although some locations may offer various advantages, back pressure valves 30a, 30b may be located at any point in the outlet airflow path 14 and may also be added to the inlet airflow path 12. In one aspect, back pressure valves 30a, 30b are configured to intentionally increase the parasitic pumping losses of the supercharger 600 to effectively provide additional braking to the engine 700. Therefore, for Figure 7B The configuration shown executes the above-mentioned procedures when bypass valve 28 is in the closed position. Figures 2 to 4B The described engine braking process ensures that all air supplied to the intake manifold 706 must be delivered by the turbocharger 600 and through valves 30a and 30b, with the clutch 800 in a high-speed gear ratio. In some instances, valves 30a and 30b are positioned by the controller 500 to a preset position or are throttled to meet specified operating setpoints, such as a pressure ratio setpoint or pressure differential setpoint across the turbocharger 600. Figure 7A As shown in the configuration, this configuration also allows the turbocharger to operate in a vacuum during cruise, which reduces the input power requirements.

[0104] refer to Figure 7C An alternative configuration is shown where the airflow sensor 22 and throttle valve 24 are located within the outlet airflow path 14, between the bypass airflow path 16 and the intake manifold 706. In some arrangements, the clutch 800 is configured to have two different gear ratios. With this configuration, during braking, the throttle valve 24 and the bypass valve 28 work together, wherein the throttle valve 24 is controlled based on the desired mass flow rate, and the bypass valve 28 is controlled to maintain the desired pressure ratio. In normal operation, the bypass valve 28 is typically open when the throttle valve 24 is closed. However, according to the above regarding... Figures 2 to 4B During the braking process described, the bypass valve 28 can be actively controlled to maintain the pressure ratio or pressure difference across the turbocharger 600. When using a dual-speed clutch, the clutch 800 can engage at a high-speed gear ratio during braking. This configuration maintains a small volume at sub-atmospheric pressure between the throttle valve and the intake port, providing a rapid response time.

[0105] refer to Figure 7DPower diagram 900 is shown to demonstrate that increasing the pressure ratio can effectively increase the load applied by the booster. As described above, the pressure ratio across the booster can be increased by implementing the aforementioned limiting strategy using one or more valves 24, 28, 30a, 30b in the inlet, outlet, and / or bypass airflows 12, 14. Figure 7D An example is shown in which this strategy is implemented, thereby increasing the pressure ratio from a normal operating state 910 with a pressure ratio between 1.2 and 1.4 to a second state 920 with a pressure ratio between 2.0 and 2.2, without changing the speed of the supercharger 600 via the clutch 800. Compared to the baseline case 910, this pressure ratio change (which represents an increase of approximately 50% to 60%) can cause the associated parasitic power loss of the supercharger 600 to exceed 150%.

[0106] To illustrate, calculations show that for the exemplary supercharged system associated with power diagram 900, a 1900cc supercharger 600 operating at 10,000 rpm has already shown a 37 kW power loss in case 920, compared to a 14 kW power loss in baseline case 910. As shown in cases 930, 940, and 950, this effect can be further increased when the supercharger speed is changed. In case 930, the speed of supercharger 600 is increased, for example, from 10,000 rpm or less in case 910 to 16,000 rpm in case 930, which increases the pressure ratio to approximately 1.6, but at a significantly higher mass flow rate compared to case 910. Therefore, the above-described supercharger example can be expected to have a power loss of approximately 39 kW in case 930, representing a 172% increase in power loss relative to baseline case 910.

[0107] Based on the operation and configuration of the limiting valve via any of the methods described above, the pressure ratio can be further increased from case 940 to cases 950a and 950b, which are between 2.2 and 2.5, although the mass flow rate is reduced compared to case 930. Even at the lower pressure ratio case 950a, the resulting power loss in the above-described booster example increases to approximately 66 kW, which represents a 359% increase in power loss relative to the baseline case 910.

[0108] Traditional hydrocarbon-based fuels such as gasoline or diesel. These engines operate on the same basic principles as conventional internal combustion engines, but have some key differences in fuel characteristics and combustion features.

[0109] Gaseous hydrogen is commonly used as a primary fuel. Hydrogen is considered a clean fuel because its combustion produces only water vapor and heat, making it an environmentally friendly alternative. Engine designs are modified to accommodate the unique properties of hydrogen, such as its wide range of combustibility and high flame speed.

[0110] The combustion process in a hydrogen internal combustion engine involves the mixing of hydrogen with air in the engine cylinders. The unique combustion characteristics of hydrogen allow for flexibility in the design of hydrogen-powered engines. Hydrogen engines can typically operate at higher compression ratios to take advantage of hydrogen's high octane rating. However, unlike conventional hydrocarbon fuels such as diesel, hydrogen does not suffer from the same problems as pre-ignition or knocking. Therefore, hydrogen engines can also operate efficiently at lower compression ratios compared to diesel engines. This lower compression ratio can be advantageous for certain hydrogen engine designs.

[0111] In some cases, H2 ICE engines are configured with a lower compression ratio to prevent autoignition of hydrogen fuel. A lower compression ratio can also be advantageous in reducing mechanical stress on engine components and potentially simplifying the overall engine design. Hydrogen combustion tends to produce lower levels of nitrogen oxides (NOx), a major cause of air pollution. The lower compression ratio in hydrogen engines can also help reduce NOx emissions compared to diesel engines. A lower compression ratio can further impact the materials used in the engine structure. Engine components need to be designed to handle the specific requirements of hydrogen combustion, and a lower compression ratio can affect the total stress on these materials.

[0112] The use of an air-charging system can improve the efficiency of H2 ICE engines operating at high λ. In the context of internal combustion engines, the term "λ" refers to the air-fuel ratio, which is precisely the ratio of the actual air-fuel mixture to the stoichiometric air-fuel ratio. The stoichiometric ratio is the chemically ideal ratio for complete combustion. A λ value of 1.0 corresponds to a stoichiometric air-fuel ratio. When an engine operates at a λ greater than 1.0, it means that there is an excess of air in the mixture compared to the stoichiometric ratio. This condition is often referred to as "lean-burn" operation. In lean-burn mixtures, combustion temperatures tend to be higher, which can affect engine performance and emissions. Lean-burn engines are often equipped with technologies such as exhaust gas recirculation (EGR) or catalytic converters to mitigate the impact on emissions. While lowering the compression ratio brings many advantages, its effects require additional design considerations in some areas of engine operation. For example, because hydrogen fuel has a stoichiometric ratio of 34:1, compared to diesel fuel's 14.4:1, an H2 ICE engine requires more than twice the intake airflow.

[0113] refer to Figure 9 This paper presents a prior art intake and exhaust system for an internal combustion engine, wherein the intake side includes an air filter, a turbocharger (Tc-Comp), an intercooler (IC), and an intake manifold (IM), and the exhaust side includes an exhaust manifold (EM), a turbine (Tc-Turbine) powered by exhaust and driving the turbocharger, and an exhaust aftertreatment system (EATS). (See reference...) Figure 10This provides an improved intake system that can provide additional air pressure to an internal combustion engine. As shown in the figure, Figure 10 The intake system further includes a supercharger (Sc) downstream of the turbocharger (Tc-Comp.) and a valved bypass device for bypassing the supercharger Sc and connecting the outlet of the turbocharger Tc-Comp to the inlet of the intercooler IC. In one aspect, the supercharger and turbocharger can be characterized as being connected in series with each other.

[0114] Figures 11 to 17 An additional intake system variant is shown, which can also be used with the intake system serving the H2 ICE. Figure 11 The intake system is shown, which includes, in sequence, an air filter, a turbocharger (Tc-C), a supercharger (Sc), and an intercooler (intercooler 1). Figure 12 The intake system is shown, which sequentially includes an air filter, a turbocharger (Tc-C), a supercharger (Sc), a bypass device with a valve, and an intercooler, the intercooler being configured in a manner generally similar to... Figure 11 The intercooler of the intake system shown. Figure 13 The intake system is shown, which includes, in sequence, an air filter, a turbocharger (Tc-C), a clutch-type turbocharger (Sc), a bypass device with a valve, and an intercooler.

[0115] Figure 14 The intake system is shown, which sequentially includes an air filter, a turbocharger (Tc-C), an intercooler (intercooler 2), a clutch-type turbocharger (Sc) and a bypass device with a valve, and another intercooler (intercooler 1). A specific advantage gained by providing an intercooler upstream of the turbocharger is that the size of the turbocharger can be significantly reduced. By cooling the air leaving the turbocharger with the intercooler, the air density increases, resulting in a smaller volume for the same mass flow rate. Since the turbocharger is a volumetric device, this reduction in volume allows for the use of a smaller turbocharger compared to the size required without an intercooler. This advantage also extends to the size of the clutch, as the clutch size depends on the size of the turbocharger.

[0116] Figure 15 The intake system is shown, which includes, in sequence, an air filter, a turbocharger (Tc-C), an intercooler (intercooler 2), a supercharger (Sc) and a bypass device with a valve, and another intercooler (intercooler 1). Figure 16An intake system is shown, which sequentially includes: an air filter; a turbocharger (Tc-C); an intercooler (intercooler 2); a recirculation valve 1602 that returns air to an upstream position of the turbocharger; a turbocharger (Sc); a bypass device with a valve; a separate recirculation valve 1604 that returns air from the downstream position of the turbocharger to the upstream position of the turbocharger; and a separate intercooler (intercooler 1).

[0117] Figure 17 An intake system is shown, comprising, in sequence, an air filter, a clutch-type supercharger (Sc) and a bypass device with a valve, a turbocharger (Tc-C), and an intercooler. In this arrangement, the supercharger is designed to be larger than in the configuration where the supercharger is downstream of the turbocharger. At any load point, for the same gear or pulley ratio, the corrected mass flow rate of the supercharger is increased. Alternatively, for a supercharger of the same size used in a configuration where the supercharger is downstream of the turbocharger, the pulley or gear size can be increased. The compressor size can also be larger compared to the configuration where the supercharger is downstream, due to the higher pressure drop in the additional piping leading to the compressor inlet. The supercharger bypass valve size can also be increased, for example, by about 30% to about 50%, compared to the configuration where the supercharger is downstream of the turbocharger. The higher inlet pressure drop in the turbocharger can result in lower boost for the same pressure specific capacity compared to the configuration where the supercharger is downstream of the turbocharger.

[0118] Figure 18 This is a summary table of the structural details of the various embodiments disclosed herein.

[0119] Figure 19A and Figure 19B They are shown respectively Figure 14 and Figure 17 The efficiency graph of the system is shown. High-efficiency islands 1902 and 1904 are identified in each efficiency graph. For example... Figure 14 As shown in structure 1902, a high-efficiency island with a near-low pressure ratio and low modified mass flow rate is preferred. Figure 19B In this process, the turbocharger operation will feature high turbocharger speed, pressure ratio, and higher corrected mass flow rate, resulting in a higher pressure ratio, higher corrected mass flow rate, and a more dispersed high-efficiency island 1904. Due to the high power of the turbocharger, Figure 19B In the example, the engine braking thermal efficiency (BTE) will be even lower.

[0120] Figure 20 The diagram shows the braking power and braking efficiency of the selected clutch-type turbocharger intake system. Figure 21 and Figure 22 A view of the proposed intake system structure is shown, for example... Figure 14 and Figure 15The exemplary system structure shown includes a turbocharger and a supercharger connected in series, and a structure including two intercoolers. According to an embodiment of this disclosure, the supercharger is provided with a bypass device with a valve, which can... Figure 21 and Figure 22 The encapsulation is shown in the diagram.

[0121] exist Figure 21 In this configuration, condenser 2102 is closest to the shroud boundary 2104. The shroud boundary 2104 defines the foremost boundary of the engine compartment 2100. A larger intercooler 2106 is located behind condenser 2102, or further away from the shroud boundary 2104. In this embodiment, the larger intercooler 2106 and... Figure 14 and Figure 15 The first intercooler in the exemplary structure or the intercooler disposed between the turbocharger and the downstream turbocharger is related.

[0122] Radiator 2108 is located behind the larger intercooler 2106, such that the larger intercooler 2106 is positioned between the condenser 2102 and the radiator 2108, and is closer to the hood boundary 2104 than the radiator 2108. Fan 2110 is located behind the radiator 2108, such that the radiator 2108 is positioned between the larger intercooler 2106 and the fan 2110, and is closer to the engine hood boundary 2104 than the fan 2110. Engine 2112 is arranged behind the fan 2110 and extends from the fan 2110 to the rear boundary 2114, such that the fan 2110 is positioned between the radiator 2108 and the engine 2112, and is closer to the hood boundary 2104 than the foremost portion of the engine 2112. The rear boundary 2114 is the boundary of the engine compartment 2100 furthest from the hood boundary 2104.

[0123] Air filter 2116 is arranged toward the rear boundary 2114 and may coincide with or overlap with the rear portion of engine 2112. Air filter 2116 may be arranged above engine 2112. Air filter 2116 is arranged off-center, such that it is closer to exhaust side boundary 2118 than intake side boundary 2120.

[0124] exist Figure 22 In this configuration, engine 2212 is positioned near shroud boundary 2204. Shroud boundary 2204 defines the foremost boundary of engine compartment 2200. Turbocharger (TC) 2222 is positioned at the end of engine 2212 adjacent to shroud boundary 2204. Turbocharger 2222 is positioned off-center, such that it is closer to exhaust side boundary 2218 than intake side boundary 2220.

[0125] A duct 2224 extends from the outlet of the turbocharger 2222 to the inlet of the larger intercooler 2206. The duct 2224 is generally arranged around the exhaust side 2218 of the engine 2212. In this embodiment, the larger intercooler 2206 and... Figure 14 and Figure 15 The first intercooler in the exemplary configuration is associated with an intercooler disposed between the turbocharger and the downstream turbocharger. The larger intercooler 2206 is located behind the engine 2212, further away from the shroud boundary 2204. The smaller intercooler 2226 is located behind the larger intercooler 2206 and may be the rearmost component in the engine compartment 2200, arranged near the rear boundary 2214. In this embodiment, the larger intercooler 2206 is associated with... Figure 14 and Figure 15 This relates to a second intercooler in an exemplary configuration or an intercooler located downstream of the turbocharger. The larger intercooler 2206 and the smaller intercooler 2226 may be arranged generally along the centerline of the engine compartment 2200.

[0126] A duct 2228 extends from the outlet of the larger intercooler 2206 to the inlet of the turbocharger 2230. The duct 2228 is generally positioned behind and towards the intake side 2220 of the engine 2212. The turbocharger 2230 is positioned at the end of the engine 2212 away from the shroud boundary 2204. The turbocharger 2230 is arranged off-center, such that it is closer to the intake side boundary 2220 than the exhaust side boundary 2218.

[0127] The duct 2232 extends from the outlet of the supercharger 2230 to the inlet of the smaller intercooler 2226. The duct 2232 is typically arranged in a first leg extending from the supercharger 2230 toward the shroud boundary 2204, a second leg generally parallel to the shroud boundary 2204, and a third leg generally along the periphery of the exhaust side 2218 of the engine 2212 and the larger intercooler 2206.

[0128] The conduit 2234 extends from the outlet of the smaller intercooler 2226 to the intake manifold. The bypass conduit 2236 for bypassing the turbocharger 2230 extends from the conduit 2228 to the third leg of the conduit 2232, connecting the outlet of the larger intercooler 2206 and the inlet of the smaller intercooler 2226.

[0129] Figure 22The arrangement specifically illustrates how the two intercooler designs disclosed herein can be configured to occupy a similar coverage area within the engine compartment as the current design. These two intercoolers can be configured to provide a heat capacity comparable to the current design, such that the outlet temperature of the second intercooler downstream of the turbocharger is no greater than 50°C, less than 50°C, no greater than 40°C, less than 40°C, no greater than 30°C, less than 30°C, etc. In an embodiment, the outlet temperature of the first intercooler located between the turbocharger and the supercharger is no greater than 50°C, less than 50°C, no greater than 40°C, less than 40°C, no greater than 30°C, less than 30°C, etc. For example, when the supercharger bypass line is fully closed and the supercharger is running. Ensuring that the supercharger inlet temperature, for example, is no greater than 50 degrees Celsius, allows the use of common automotive materials in the supercharger, saving cost and weight compared to using high-temperature materials. For example, common automotive materials include steel alloys, aluminum, various plastics, and rubber, while high-temperature materials are typically composed of refractory metals such as tungsten, molybdenum, tantalum, and specialized ceramics.

[0130] In some implementations, it is advantageous to position the supercharger downstream of the turbocharger in terms of supercharger size and power consumption, because the density of the intake air received from the turbocharger is greater than that of atmospheric air.

[0131] In this example, a valved bypass device around the turbocharger allows power to be reduced from 80 kW to 15 kW (13 L; LPDI; λ–2.2 and BMEP 23 bar).

[0132] In this example, providing a clutch to the turbocharger allows the turbocharger to consume zero power when not in use, thus saving 15 kW (13 L; LPDI; λ–2.2 and BMEP 23 bar).

[0133] In some instances, and as previously noted, providing an intercooler between the turbocharger and the supercharger allows for a reduction in the supercharger's size. In some instances, the intercooler is integrally formed into the supercharger. In some instances, the system includes a supercharger with an integrally formed intercooler and one or more separate intercoolers. In some instances, the intercooler is separate from the supercharger. As previously mentioned, this arrangement is made possible by the increased density of the intake air to the supercharger (which is a volumetric device that increases mass flow rate). Note that a smaller supercharger has less inertia, which makes a clutch more feasible.

[0134] In this example, the supercharger is located upstream of the turbocharger. With this arrangement, the supercharger can be either clutch-type or non-clutch-type. Integrating an intercooler between the turbocharger and the supercharger allows for a reduction in the turbocharger's size. The intercooler can be integrally formed into the supercharger or turbocharger or separate from it.

[0135] In some configurations, for steady-state conditions at low altitudes (preferably below 4000 feet), at least two possible operating strategies exist, as follows. In one strategy, the supercharger operates at a lower speed (<1200 RPM) along with the turbo compressor. This may be a preferred strategy considering the system's BTE (brake thermal efficiency) because the turbocharger can handle high speed and load demands (relatively large turbocharger). In one example, the supercharger operates below 900 RPM on the H2 ICE. In another example, this strategy is implemented when the H2 ICE load exceeds 50% of its maximum load.

[0136] In alternative strategies, the turbocharger is used in conjunction with a relatively small turbine (lower mass flow handling capacity) at high speeds (<2100 RPM) and high loads (50%–100%). Due to the high power consumption of the turbocharger resulting in a low BTE, this strategy may not be preferred in some applications. For low-speed operation (<1200 RPM), a clutch for the turbocharger may be required, along with an additional intercooler, which can be the same as the truck intercooler.

[0137] During transient operation and at high altitudes, the supercharger and turbocharger can work together, for example, at loads above 25%, engine speeds above 700 RPM H2 ICE, and altitudes above 4,000 feet.

[0138] Turbochargers can be configured in various ways. For example, a turbocharger can be a standard-grade turbocharger capable of handling outlet temperatures below 180°C (not necessarily requiring an intercooler); if the outlet temperature is within the 180°C limit, the inlet temperature can be up to 140°C. A turbocharger can also be configured as a high-temperature turbocharger capable of handling high inlet temperatures (~240°C). The turbocharger can also be belt- or motor-driven and may or may not have a bypass line. In examples, the bypass line is an electronic or mechanical bypass line and may include a switching valve or a regulating valve. In examples, a clutch can be provided for the turbocharger, for example when the turbocharger is a belt-driven turbocharger. In examples without a clutch, the turbocharger can operate at very low pressure ratios at high engine speeds, with the compressor handling the boost requirement entirely. Dual-valve configurations can also be used in special clutchless cases, where the valve assembly assists the turbocharger in rotating to achieve the required pressure ratio, and the compressor meets the boost requirement through a bypass passage to the engine manifold. If the increased gear and / or pulley ratio can be handled, the clutch configuration can help reduce the size of the turbocharger and improve BTE, transient performance, and durability.

[0139] In some applications, a turbocharger can be used to extract hydrogen from the crankcase. In this case, the turbocharger will blow air into the oil pan to maintain an H2 level below 3%-6%. This operation can be performed by blowing or pulling air across the oil pan at discrete intervals (preferably) or continuously. This operation can be prevented during transient situations.

[0140] By increasing the intake manifold pressure, the turbocharger can also be used as a secondary braking device.

[0141] Figure 23 This is a schematic diagram of the combustion and braking combined system structure 2300 using a three-way valve 2302. Figure 23 The structure sequentially includes an air filter, a turbocharger (TC), a first intercooler (IC 1), a supercharger (SC), a second intercooler (CAC), and extends to the intake manifold. In an embodiment, the second intercooler (CAC) may be a supercharged air cooler. A three-way valve 2302 is provided to replace the supercharger bypass line, such as in... Figure 14 The example system shows a bypass line. Therefore, a three-way valve 2302 is used to provide a recirculation path 2304 in addition to the booster bypass path 2306.

[0142] Return to reference Figure 7D Power diagram 900 illustrates the increased braking power provided by the high-speed turbocharger compared to a single-speed turbocharger. In example structure 2300, the speed device 2314 is connected to the turbocharger (SC) via a clutch 2316 and provides high-speed operation of the turbocharger for increased braking power. In this example, the speed device 2314 provides speed factors of 1.1, 1.2, 1.3, 1.4, 1.5, etc., exceeding the baseline speed factor 1 associated with the turbocharger without the speed device 2314. In implementations, the speed device 2314 can be omitted from the structure.

[0143] The turbocharger bypass path 2306 directs fluid from the turbocharger inlet 2310 to the turbocharger outlet 2308, bypassing the turbocharger. In this embodiment, the turbocharger bypass path 2306 allows 100% flow to pass through the turbocharger inlet 2310. The recirculation path 2304 directs flow from the downstream intercooler outlet 2312 back to the turbocharger inlet 2310. During operation, the turbocharger bypass path 2306 is used during drive operation.

[0144] During braking, the three-way valve 2302 is reconfigured to alternatively use the recirculation path 2304 to provide additional load to the turbocharger to increase braking power. The increased inlet pressure consumes more turbocharger power compared to the standard inlet pressure condition. Braking power is further increased by the increased fluid density as the fluid exits the downstream intercooler.

[0145] Figure 24 yes Figure 23 A schematic diagram of an alternative configuration 2350 for a combustion and braking combined system structure. Exemplary configuration 2350 includes a turbocharger bypass path 2306 and an alternative cooling path 2352. The alternative cooling path 2352 directs flow from the turbocharger outlet 2308 to the upstream intercooler inlet 2354. In an embodiment, the speed device can be excluded from the configuration.

[0146] Figure 25 This is a schematic diagram of a combustion and braking combined system using a dual-valve structure. Figure 25 The structure consists of an air filter, a turbocharger (TC), a first intercooler (IC 1), a supercharger (SC), a second intercooler (CAC), and extends to the intake manifold.

[0147] The turbocharger bypass line 2502 directs flow from the turbocharger inlet (SC) to the inlet of the second intercooler (CAC), bypassing the turbocharger. Flow through the turbocharger bypass line 2506 is controlled by a valve in the turbocharger bypass line. This valve may be a throttle valve. The valve can typically open during drive operation to bypass the turbocharger and close during braking operation to allow the turbocharger to assist braking. The turbocharger bypass line 2506 can be configured to allow up to 100% flow to bypass the turbocharger when the valve is fully open. The turbocharger (SC) can also be engaged or disengaged via clutch 2516 during bypass operation. In an embodiment, the valve in the turbocharger bypass line can be throttled during transient or low-load drive operation.

[0148] During braking operation, brake recirculation path 2504 is used to provide additional flow and pressure to the inlet of the booster (SC). Figure 25 An example illustrates a brake recirculation path 2504 that directs flow from the outlet of the downstream intercooler (CAC) to the inlet of the supercharger (SC). In this embodiment, the valve in the brake recirculation path 2504 is a throttle valve used to control the load on the supercharger (SC) by controlling the flow through the brake recirculation path 2504. A throttle valve in the supercharger bypass line provides variable control of bypassing the supercharger. For example, the supercharger can be bypassed during a subset of drive conditions, where the throttle valve is fully open; and throttled or closed when supercharger operation is desired, such as during transient or low-speed, high-load conditions. The throttle valve for supercharger bypass can be coupled with the operation of a clutch in a clutch-type supercharger. For example, the supercharger can be in neutral when the throttle valve is fully open and in online mode when the throttle valve is throttled or closed.

[0149] In implementations, the turbocharger bypass line is sized such that when the bypass line is open (e.g., when the valve in the bypass line is fully open), 100% of the system flow can bypass the turbocharger. In examples, the size of the turbocharger bypass line can be determined by the turbocharger outlet, for example, the diameter of the bypass line is chosen to be equal to the turbocharger outlet path. In some examples, the diameter of the turbocharger bypass line can be 4 inches, 4.5 inches, 5 inches, etc. The recirculation path can be smaller than the turbocharger bypass line, for example, having a diameter of 1 inch, 2 inches, or 3 inches. In examples, the recirculation path can be constructed using flexible hoses (e.g., rubber tubing).

[0150] Figure 26 yes Figure 25 A schematic diagram of the alternative structural configuration for the combustion and braking combined system. Figure 26 An example illustrates a brake recirculation path 2604, which directs flow from the outlet of the turbocharger (SC) to the inlet of the upstream intercooler (IC 1). In this embodiment, the valve in the brake recirculation path 2604 is a throttle valve used to provide control over the flow through the brake recirculation path 2604.

[0151] Figure 27 yes Figure 25 A schematic diagram of an alternative configuration for the combustion and braking combined system structure. Figure 27 The example illustrates a brake recirculation path 2704, which directs flow from the outlet of the downstream intercooler (CAC) to the inlet of the upstream intercooler (IC1). In this embodiment, the valve in the brake recirculation path 2704 is a throttle valve.

[0152] In these cases, refer to Figures 23 to 27 An example of a combustion and braking combined system structure is shown where the braking recirculation path is configured to reduce the temperature of the recirculated air entering the turbocharger during braking. This increases the air density as it passes through intercoolers (e.g., upstream intercooler (IC1) or downstream intercooler (CAC)) and thus enables greater braking power. In some embodiments, one or more intercoolers, and in some cases preferably the downstream intercooler, may be a boost air cooler. Increasing the size of the intercooler can further increase braking power in both upstream and downstream cases. The cooled air leaving the intercooler has a greater density and therefore can contribute more braking power when directed to the turbocharger because denser air requires more power from the turbocharger to move, increasing the parasitic load imposed on the system by the turbocharger.

[0153] Figure 28These are a pair of graphs illustrating the effect of the accelerator on the braking and boosting power of the turbocharger. In this example, the effect is demonstrated based on an accelerator providing a speed factor of 1.4. When the turbocharger outlet temperature is below 150 degrees Celsius, the mechanical losses associated with the turbocharger almost double to improve braking performance by 10% to 45%. In examples where the turbocharger operates at speeds exceeding 20,000 rpm, a larger speed factor (e.g., > 1.4) can be used, and therefore greater braking power can be achieved.

[0154] Braking power can be further increased by allowing the turbocharger outlet temperature to rise to up to 180°C over a short period of time, such as a continuous duration of about 2 minutes. A 2-minute duration is typically much longer than a normal engine braking event, which usually lasts less than 30 seconds.

[0155] Figure 29 These are efficiency diagrams related to the accelerator. Diagram 2902 shows the efficiency of an exemplary single-speed supercharger with a gear ratio of 7 and a speed factor of 1. Diagram 2904 shows the change in efficiency when an accelerator is added to a system with a supercharger. In this example, the accelerator increases the gear ratio to 9.8 with a speed factor of 1.4. The introduction of the accelerator allows the supercharger to operate at high pressure ratios and high airflow, increasing supercharger power and providing greater braking power. When the supported supercharger can withstand high pressure ratios and correspondingly higher flow rates, greater braking power from the supercharger can be utilized. Due to the high airflow, the turbine inlet temperature decreases at low speeds. This helps cool the injectors and avoids hot spots in the combustion chamber, thus helping to prevent pre-ignition and misfire when switching to drive mode.

[0156] Figure 30 This is a schematic diagram of a combustion and braking combined system structure 3000, in which the turbocharger is disconnected during braking. Structure 3000 sequentially includes an air filter, a turbocharger (TC), a first intercooler (IC1), a first disconnect device 3008, a turbocharger (SC), a second disconnect device 3006, a second intercooler (CAC), and exhaust to the intake manifold. In an embodiment, one or both of the first and second disconnect devices 3008 and 3006 are three-way valves.

[0157] Figure 30 The implementation allows the supercharger (SC) to disconnect by opening the first and second disconnect devices 3008, 3006. The supercharger (SC) can then be operated at full power to maximize braking performance. A throttle valve 3002 in the supercharger bypass line 3010 allows bypassing the supercharger (SC). During braking operation, the throttle valve 3002 operates in the open position when the supercharger is disconnected.

[0158] Another throttle valve 3004 is located downstream of a second disconnect device 3006, which is positioned at the outlet of the supercharger (SC). The throttle valve 3004 and the second disconnect device 3006 operate to switch the supercharger (SC) to an independent supercharger mode. The independent supercharger mode allows the supercharger to operate at its maximum possible power ratio to draw more power from the drive shaft. In this independent supercharger mode, fluid can be supplied directly from the air filter to the inlet of the supercharger (SC) via an alternative path 3012 provided by the first disconnect device 3008. The increased supercharger power consumption enables a significant increase in braking power.

[0159] Figure 31A This is a graph showing braking performance without an acceleration device. The supercharger contributes 100% of its power to provide increased braking performance at high engine speeds, exceeding that of the unsupercharged H2 engine. Figure 31B This is a graph showing the braking performance with the accelerator and supercharger (SC) disconnected. At an engine speed of 2000 RPM, in this example, the supercharger (SC) with the accelerator disconnected provides an additional 28 kW of braking power benefit compared to a supercharger without the accelerator in the circuit. While the absolute value of the power increase (in kW) can vary between different applications, the disclosed design consistently achieves a power increment of 8-10%.

[0160] The braking benefit is present at engine speeds of 1600 rpm, while the benefit is relatively smaller (approximately 6 kW) when the turbocharger without acceleration is disconnected, compared to a turbocharger without acceleration in the circuit. Figure 32 This is an efficiency diagram related to the deactivation of the turbocharger during braking. When the turbocharger is deactivated with a speed factor of 1, its operating point shifts to the maximum power ratio and maximum power at the same operating speed. When the turbocharger is deactivated with a speed factor of 1.4 (e.g., with an acceleration device), the operating point shifts further to the maximum speed and maximum power achievable by the turbocharger.

[0161] Figure 33 This is an example of an exhaust gas recirculation architecture. Figure 34 It is another exhaust gas recirculation structure. Figure 34 The structure includes an optional acceleration device. Figure 34 Structure and Figure 33 The difference also lies in the provision of the brake recirculation line 3404. Figure 33 and Figure 34Each of these components, in sequence, includes an air filter, a turbocharger (TC), a first intercooler (IC 1), a clutch-type turbocharger (SC) with a bypass line including a throttle valve, a second intercooler (CAC), and exhaust to the intake manifold. Exhaust gas from the exhaust manifold is diverted from the turbine through an exhaust gas recirculation (EGR) valve and enters the EGR cooler. The cooled gas is then directed to the inlet of the turbocharger (SC). The turbochargers (SC) in these examples are pulley-driven turbochargers, driven by connecting rods from the engine crankshaft.

[0162] Recirculating a portion of the exhaust gas to the turbocharger (SC) inlet allows a dense, high-pressure exhaust flow to further pressurize the turbocharger (SC), thereby pushing more air mass into the cylinders and increasing braking power. Exhaust gas recirculation (EGR) allows for lower turbine inlet pressure, thereby reducing the turbocharger (TC) pressure ratio and thus the turbocharger (TC) speed, providing a higher boost margin. Including an EGR cooler also lowers the temperature of the gases to increase their density. In some embodiments, the EGR cooler may be omitted. An active device such as an EGR pump (not shown) may be used to regulate the EGR flow rate instead of an EGR valve. Figure 33 and Figure 34 An example is shown upstream of the EGR cooler. The EGR valve provides control over the recirculation flow rate to achieve maximum possible braking.

[0163] Figure 35 It is an exemplary exhaust gas recirculation structure with a turbocharger disconnect device. Figure 36 This is another exemplary exhaust gas recirculation structure with a turbocharger disconnect device. Figure 36 The structure includes an optional acceleration device. Figure 35 and Figure 36 Each of these components sequentially includes an air filter, a turbocharger (TC), a first intercooler (IC 1), a first disconnect device 3502, a clutch-type turbocharger (SC) with a bypass line including a throttle valve (throttle valve A), a second disconnect device 3504, a second intercooler (CAC), and exhaust to the intake manifold. Exhaust gas from the exhaust manifold is diverted from the turbine by an exhaust gas recirculation (EGR) valve and enters the EGR cooler. The cooled gas is then directed through the first disconnect device 3502 to the inlet of the turbocharger (SC), which may be a three-way valve to receive an alternative inlet EGR passage. The second disconnect device 3504 may also be a three-way valve with an alternative outlet path, discharging exhaust gas to the atmosphere via a throttle valve (throttle valve B) to allow the turbocharger (SC) to disconnect and operate at maximum power. The turbocharger (SC) in these examples is a pulley-driven turbocharger, driven by the engine crankshaft via a connecting rod.

[0164] A portion of the exhaust gas is recirculated to the turbocharger (SC) inlet, allowing the dense, high-pressure exhaust flow to be further pressurized, thereby achieving higher turbocharger mechanical parasitic loads and braking power. A throttle valve (throttle valve B) in the downstream turbocharger disconnect line, leading to ambient air, helps control the turbocharger pressure ratio via a second disconnect device 3504. The turbocharger pressure ratio is controlled to its maximum limit to provide maximum turbocharger power.

[0165] Controller 500

[0166] Implementations of the systems and methods disclosed herein can be carried out on computing devices such as electronic controllers. Reference now is made to... Figure 8 A block diagram of an instance of controller 500 is shown, on which various aspects of this disclosure can be implemented. In an embodiment, controller 500 is deployed as a component of a cloud computing node.

[0167] The controller 500 can work with other general-purpose or special-purpose computing system environments or configurations. Examples of well-known computing systems, environments, or configurations suitable for use with the controller 500 include, but are not limited to, personal computer systems, server computer systems, thin clients, thick clients, handheld or notebook devices, multiprocessor systems, microprocessor-based systems, set-top boxes, programmable consumer electronics, network PCs, microcomputer systems, mainframe computer systems, and distributed cloud computing environments that include any of the above systems or devices.

[0168] Controller 500 can be described within the general context of computer system processing instructions (such as program modules) processed by a computer system. Generally, program modules may include routines, programs, objects, components, logic, data structures, etc., that perform specific tasks or implement specific abstract data types. Controller 500 can be implemented in a distributed cloud computing environment where tasks are performed by remote processing devices linked via a communication network. In a distributed cloud computing environment, program modules may reside in local and / or remote computer system storage media, including memory storage devices.

[0169] like Figure 8 As shown, the controller 500 is illustrated in the form of a general-purpose computing device. Components of the controller 500 may include, but are not limited to, one or more processors 502, a memory 504, and a bus 506 that connects different system components (including the memory 504) to the processor 502.

[0170] Processor 502 processes instructions for software that can be loaded into memory 504. Processor 502 can be multiple processors, multiprocessor cores, or some other type of processor, depending on the specific implementation. Furthermore, processor 502 can be implemented using one or more different processor systems, where the main processor and secondary processors coexist and may reside on a single chip. In another example, processor 502 can be a symmetric multiprocessor system containing multiple processors of the same type.

[0171] Bus 506 represents one or more of a variety of bus architectures, including memory buses or memory controllers, peripheral buses, accelerated graphics ports, and processor buses or local buses that use any of the various bus architectures. As examples and not limitations, such architectures include the Industry Standard Architecture (ISA) bus, the Micro Channel Architecture (MCA) bus, the Enhanced ISA (EISA) bus, and the Peripheral Component Interconnect (PCI) bus.

[0172] The controller 500 may include various computer system readable media. Such media may be any available media accessible by the controller 500, and may include volatile and non-volatile media as well as removable and non-removable media.

[0173] Memory 504 may include computer system readable media in the form of volatile memory, such as random access memory (RAM) 508 and / or cache 510. Controller 500 may also include other removable / non-removable, volatile / non-volatile computer system storage media. By way of example only, storage system 512 may be provided for reading and writing from non-removable, non-volatile magnetic media, such as hard disk drives. Although not shown, disk drives for reading and writing to removable non-volatile disks and optical disk drives for reading or writing to removable non-volatile optical disks or other optical media may be provided. In this case, each drive may be connected to bus 506 via one or more data media interfaces. Memory 504 may include a program product having at least one set of program modules configured to perform embodiments of the invention. As used herein, "set" means one or more items when referring to items. For example, a set of program modules is one or more program modules.

[0174] A program 514 having a set of program modules 516, along with an operating system, one or more application programs, other program modules, and program data, can be stored in memory 504 as an instance. Each or some combination of the operating system, one or more application programs, other program modules, and program data may include an implementation of a network environment. Program modules 516 typically perform functions and / or methods as described herein in embodiments of the invention. Program modules 516 include a fusion module 514, a weight / confidence module 418, and a fault detection module 520.

[0175] The controller 500 can also communicate with one or more external devices 518, such as a keyboard, mouse, monitor, or one or more other devices, to enable a user to interact with the controller 500. The external devices 518 may also include any device (e.g., a network interface card, modem, etc.) that enables the controller 500 to communicate with one or more other computing devices. This communication may occur via I / O interface 520. I / O interface 520 may correspond to external interface 518. The controller 500 may communicate with one or more networks, such as a local area network (LAN), a general wide area network (WAN), or a public network (such as the Internet), via network adapter 522.

[0176] Network adapter 522 communicates with other components of controller 500 via bus 506. Figure 5 Other hardware and / or software components, which may not be described herein, may be used with the controller 500. Examples include, but are not limited to, microcode, device drivers, redundant processor units, external disk drive arrays, RAID systems, tape drives, and data archiving storage systems.

[0177] Illustrative examples of the systems and methods described herein are provided below. Implementations of the systems or methods described herein may include any one or more, and any combination of, the aspects described below.

[0178] Aspect 1. An intake system for an internal combustion engine. The system includes: a turbocharger; a supercharger connected in series with the turbocharger; a first intercooler between the turbocharger and the supercharger; and a second intercooler downstream of the supercharger.

[0179] Aspect 2. The system according to Aspect 1, wherein the second intercooler has an outlet temperature of less than or equal to 50°C, more preferably less than or equal to 40°C, and even more preferably less than or equal to 30°C.

[0180] Aspect 3. The system according to Aspect 2, wherein the first intercooler has an outlet temperature of less than or equal to 50°C, more preferably less than or equal to 40°C, and even more preferably less than or equal to 30°C.

[0181] Aspect 4. The system according to any one of aspects 1-3 further includes a first bypass line that diverts the flow around the booster during drive operation.

[0182] Aspect 5. The system of claim 4, wherein the first bypass line diverts the flow from the inlet of the turbocharger to the inlet of the second intercooler.

[0183] Aspect 6. The system according to aspect 4 or 5 also includes a first throttle valve in the first bypass line.

[0184] Aspect 7. The system according to any one of Aspects 1-6 further includes a second bypass line that provides additional flow to the inlet of the booster during braking.

[0185] Aspect 8. The system according to aspect 7, wherein the second bypass line directs flow from the outlet of the second intercooler to the inlet of the turbocharger.

[0186] Aspect 9. The system according to aspect 7 or 8 further includes a first bypass line that diverts flow around the turbocharger during drive operation, wherein the diameter of the first bypass line is larger than the diameter of the second bypass line.

[0187] Aspect 10. The system according to aspect 9, wherein the second bypass line is a rubber hose.

[0188] Aspect 11. The system according to any one of Aspects 7-10 further includes a second throttle valve in the second bypass line.

[0189] Aspect 12. A system according to any one of aspects 1-11, wherein the turbocharger is a clutch-type turbocharger.

[0190] Aspect 13. The system according to aspect 12, wherein the clutch-type turbocharger includes an integrally formed clutch.

[0191] Aspect 14. The system according to aspect 12 or 13 also includes an acceleration device connected to a clutch-type supercharger.

[0192] Aspect 15. A system according to any one of Aspects 1-14, wherein the supercharger is pulley driven, gear driven, or electric motor driven.

[0193] Aspect 16. The system according to aspect 15, wherein the supercharger is driven by an electric motor and the supercharger is a two-speed supercharger.

[0194] Aspect 17. The system according to any one of Aspects 1-16, wherein the second intercooler is discharged into the intake manifold of the hydrogen internal combustion engine.

[0195] Aspect 18. A method of operating an intake system for an internal combustion engine, the intake system comprising, in sequence, a turbocharger, a first intercooler, a supercharger, and a second intercooler. The method includes: operating the intake system to support the internal combustion engine in a drive mode by opening a first throttle valve in a first bypass line to bypass the supercharger; and operating the intake system to support the internal combustion engine in a braking mode by closing the first throttle valve in the first bypass line.

[0196] Aspect 19. According to the system of aspect 18, wherein operating the intake system to support the internal combustion engine in braking mode further includes: directing airflow from the outlet of the second intercooler to the inlet of the turbocharger by opening a second throttle valve in a second bypass line.

[0197] Aspect 20. According to the method of Aspect 18 or 19, wherein the turbocharger is a clutch-type turbocharger.

[0198] Aspect 21. The method according to aspect 20, wherein operating the intake system to support the internal combustion engine in drive mode further includes: operating the clutch to put the turbocharger in neutral when the throttle valve in the first bypass line is opened.

[0199] Aspect 22. The method according to aspect 20 or 21, wherein operating the intake system to support the internal combustion engine in braking mode further includes: operating the clutch to connect the turbocharger to the acceleration device.

[0200] Aspect 23. The method according to any one of Aspects 18-22, wherein the turbocharger is an electric motor driven turbocharger having an electric motor having at least two speeds, wherein operating the intake system to support the internal combustion engine in a drive mode further includes: operating the electric motor at a first speed, and wherein operating the intake system to support the internal combustion engine in a braking mode further includes: operating the electric motor at a second speed, wherein the second speed is greater than the first speed.

[0201] Aspect 24. The method according to any one of Aspects 18 to 23, wherein the internal combustion engine is a hydrogen internal combustion engine.

[0202] Aspect 25. An intake system for an internal combustion engine, comprising a turbocharger, a first intercooler, a supercharger, and a second intercooler arranged in series in an engine compartment, such that the first intercooler is located at the rear boundary of the engine compartment, the second intercooler is located in front of the first intercooler, and the turbocharger and the supercharger are each located in front of the second intercooler.

[0203] Aspect 26. The intake system according to aspect 25 also includes a turbocharger bypass line arranged between the second intercooler and the turbocharger.

[0204] Aspect 27. The intake system according to Aspect 25 or 26, wherein the second intercooler is larger than the first intercooler.

[0205] Aspect 28. A method for enhancing depressurized engine braking to compensate for reduced dynamic braking potential in a low-compression internal combustion engine. The method includes initiating engine braking operation in an internal combustion engine, wherein the internal combustion engine consumes hydrogen fuel and has a compression ratio of no more than 14:1 in normal operating mode, increasing intake manifold pressure using an air compressor to generate a pressurized airflow, introducing the pressurized airflow into cylinders of the internal combustion engine, compressing air in the cylinders using pistons, and releasing the compressed air from the cylinders in a controlled compression release event.

[0206] Aspect 29. According to the method of aspect 28, wherein when the piston is at the bottom dead center of the cylinder, an increase in pressure in the cylinder is generated by the air compressor.

[0207] Aspect 30. The method according to Aspect 28 or 29, wherein the air compressor is one of a booster, an electric booster, a turbocharger, and an electric turbocharger.

[0208] Aspect 31. According to the method of aspect 30, wherein the air compressor is a booster, and the booster includes a clutch.

[0209] Aspect 32. According to the method of aspect 31, the clutch is a three-way clutch.

[0210] Aspect 33. According to the method of aspect 32, the three-way clutch includes: a neutral position; a first gear drive position for driving; and a second gear drive position for braking.

[0211] Aspect 34. According to the method of aspect 33, the second gear drive position operates the supercharger at a higher speed than the first gear drive position.

[0212] Aspect 35. According to the method of aspect 34, wherein the second gear drive position connects the booster to the acceleration device.

[0213] Aspect 36. The method according to aspect 35 also includes operating a valve in the cooling bypass line during engine braking operation.

[0214] Aspect 37. According to the method of aspect 36, wherein the cooling bypass line is connected to one of the downstream intercooler outlet and the turbocharger inlet, the turbocharger outlet and the upstream intercooler inlet, and the downstream intercooler outlet and the upstream intercooler inlet.

[0215] Aspect 38. According to the method of aspect 36 or 37, wherein the valve is a three-way valve.

[0216] Aspect 39. The method according to any one of Aspects 30 to 38, wherein the air compressor includes a ratioing device having at least two speeds.

[0217] Aspect 40. The method according to aspect 39, wherein at least two speeds include a first speed for driving operation and a faster second speed for braking operation.

[0218] Aspect 41. The method according to any one of Aspects 28-40, wherein the air compressor applies a parasitic load to the internal combustion engine.

[0219] Aspect 42. The method according to any one of Aspects 28-41, wherein the air compressor includes a throttle valve in the intake airflow.

[0220] Aspect 43. The method according to any one of Aspects 28-42, wherein the internal combustion engine has a compression ratio in the range of 10:1 to 13:1.

[0221] Aspect 44. The method according to any one of Aspects 28-43 further includes drawing air into the cylinder by a piston during the second intake stroke, wherein the internal combustion engine has four cycles of the crankshaft of the internal combustion engine, and the second intake stroke is the third of the four cycles; adding additional air to the cylinder by an air compressor during the second intake stroke; compressing the air in the cylinder by a piston during the exhaust stroke; and releasing the compressed air from the cylinder.

[0222] Aspect 45. A system for decompression braking, comprising: a hydrogen internal combustion engine (H2 ICE) having at least one cylinder, the at least one cylinder including a piston and an intake valve; an air compressor in communication with the intake valve; and a controller having a propulsion mode and a braking mode, wherein during the braking mode, the air compressor is operated by the controller to supply air to the cylinder via the piston during the intake stroke.

[0223] Aspect 46. The system according to aspect 45, wherein the intake valve has a lift height and a lift duration, and at least one of the lift height and the lift duration is reduced during the braking mode compared to the lift height and the lift duration during the propulsion mode, so as to increase the pressure ratio across the air compressor.

[0224] Aspect 47. The system according to aspect 45 or 46, wherein the system includes a limiting valve device operable in the braking mode to increase the pressure ratio across the air compressor during operation in the braking mode.

[0225] Aspect 48. The system according to aspect 47, wherein the controller operates the air compressor in braking mode at an increased speed compared to the speed of the air compressor in propulsion mode.

[0226] Aspect 49. A method of operating a system comprising a hydrogen internal combustion engine and a turbocharger between a normal operating mode and an engine braking mode. The method includes: operating the system in a normal operating mode, wherein the turbocharger operates at a first rotational speed to deliver air to the intake manifold of the engine; and operating the system in an engine braking mode. The engine braking mode includes operating the turbocharger to deliver an airflow to the intake manifold; increasing the pressure ratio across the turbocharger by operating the turbocharger at a second rotational speed higher than the first rotational speed and by operating one or both of an operating limiting valve device to increase parasitic losses; introducing the airflow into the cylinders of the internal combustion engine; compressing the air in the cylinders using a piston; and releasing the compressed air from the cylinders in a controlled compression release event.

[0227] Aspect 50. According to the method of aspect 49, the step of increasing the pressure ratio across the booster includes operating the limiting valve device.

[0228] Aspect 51. According to the method of aspect 50, the step of increasing the pressure ratio at both ends of the booster includes operating the booster at a second rotational speed.

[0229] Aspect 52. According to the method of aspect 51, the step of increasing the pressure ratio across the booster includes operating the booster at a second rotational speed and operating the limiting valve device.

[0230] Aspect 53. The method according to any one of Aspects 50-52, wherein the limiting valve device is located in the inlet airflow path upstream of the turbocharger or in the outlet airflow path downstream of the turbocharger.

[0231] Aspect 54. The method according to any one of aspects 50-53, wherein the limiting valve device comprises a plurality of limiting valve devices.

[0232] Aspect 55. The method according to any one of Aspects 50-54, wherein the limiting valve device is located between the engine intake manifold and the turbocharger.

[0233] Aspect 56. The method according to any one of Aspects 50-55, wherein the system includes a throttle valve device and a booster bypass valve device separate from the limiting valve device.

[0234] Aspect 57. The method according to aspect 56, wherein the air flow sensor is located between the turbocharger and the engine intake manifold, and wherein one or both of the throttle valve device and the bypass valve device operate in engine braking mode based at least in part on the input from the air flow sensor.

[0235] Aspect 58. The method of any one of Aspects 49-57, wherein the step of increasing the pressure ratio across the turbocharger comprises: operating the turbocharger at a second speed higher than the first speed.

[0236] Aspect 59. According to the method of aspect 58, operating the booster includes operating the clutch.

[0237] Aspect 60. According to the method of aspect 59, wherein the acceleration device is connected to the supercharger via a clutch.

[0238] Aspect 61. The method according to aspect 60, wherein the acceleration device is used to increase the second speed during engine braking operation.

[0239] Aspect 62. The method according to aspect 60 or 61, wherein the system includes a booster bypass valve device separate from the limiting valve device, the booster bypass valve device including a three-way valve.

[0240] Aspect 63. The method according to aspect 62, wherein a first path provided by a three-way valve directs flow from the outlet of the turbocharger to the inlet of the turbocharger, and a second path provided by a three-way valve directs flow from the outlet of the downstream intercooler to the inlet of the turbocharger.

[0241] Aspect 64. The method according to aspect 62 or 63, wherein a first path provided by a three-way valve directs flow from the outlet of the turbocharger to the inlet of the turbocharger, and a second path provided by a three-way valve directs flow from the outlet of the turbocharger to the inlet of the upstream intercooler.

[0242] Aspect 65. The method according to any one of aspects 60-64, wherein the system includes a booster bypass valve device separate from the limiting valve device, the booster bypass valve device including a throttle valve.

[0243] Aspect 66. The method according to aspect 65, wherein the system includes a first three-way valve upstream of the turbocharger and a second three-way valve downstream of the turbocharger, and the first three-way valve and the second three-way valve together disconnect the turbocharger.

[0244] Aspect 67. The method according to aspect 66 also includes disconnecting the supercharger during engine braking operation.

[0245] Aspect 68. An intake system for delivering ambient air to an intake manifold of a low-compression internal combustion engine. The intake system includes: a turbocharger; a clutch-type turbocharger connected in series with the turbocharger; and a valved bypass device configured to selectively allow air to bypass the clutch-type turbocharger.

[0246] Aspect 69. The intake system according to aspect 68, wherein the supercharger is downstream of the turbocharger.

[0247] Aspect 70. The intake system according to aspect 68 or 69, wherein the supercharger is upstream of the turbocharger.

[0248] Aspect 71. The intake system according to any one of Aspects 68-70 further includes a first intercooler located between the supercharger and the turbocharger.

[0249] Aspect 72. The intake system according to aspect 71 also includes a second intercooler located downstream of the turbocharger.

[0250] Aspect 73. The intake system according to aspect 72, wherein at least one of the first intercooler and the second intercooler is integrally formed with the turbocharger in a shared housing.

[0251] Aspect 74. An intake system according to aspect 72 or 73, wherein at least one of the first intercooler and the second intercooler is separate from the turbocharger.

[0252] Aspect 75. An intake system according to any one of Aspects 68-74, wherein the supercharger is driven by an electric motor.

[0253] Aspect 76. An intake system according to any one of Aspects 68-75, wherein the supercharger is driven by a pulley.

[0254] Aspect 77. An intake system for delivering ambient air to an intake manifold of a low-compression internal combustion engine. The intake system includes: a turbocharger; a clutch-type turbocharger connected in series with the turbocharger and downstream of the turbocharger; an intercooler located downstream of the turbocharger and upstream of the turbocharger; and a valved bypass device configured to selectively allow air to bypass the clutch-type turbocharger.

[0255] Aspect 78. According to the intake system of aspect 77, it also includes another intercooler located downstream of the turbocharger.

[0256] Aspect 79. The intake system according to aspect 77 or 78 also includes an acceleration device associated with a clutch-type supercharger.

[0257] Aspect 80. The intake system according to aspect 79 also includes: another bypass device with a valve, connecting the outlet of the turbocharger and the inlet of the intercooler.

[0258] Aspect 81. The intake system according to any one of Aspects 77-80 further includes an exhaust recirculation path.

[0259] Aspect 82. The intake system according to aspect 81, wherein the exhaust recirculation path directs the exhaust flow to the inlet of the turbocharger.

[0260] Aspect 83. An intake system according to aspect 81 or 82, wherein the exhaust recirculation path includes at least one of a control valve and a pump.

[0261] Aspect 84. An intake system according to any one of aspects 81-83, wherein the exhaust recirculation path includes a cooler.

[0262] Aspect 85. A method of operating an intake system, the method comprising: operating a clutch-type supercharger during transient operation, wherein the clutch-type supercharger is connected in series with a turbocharger; and bypassing the clutch-type supercharger during drive operation using a valved bypass line.

[0263] Aspect 86. The method according to aspect 85 also includes operating the clutch-type turbocharger during low-speed steady-state operation.

[0264] Aspect 87. The method according to Aspect 85 or 86, wherein low-speed steady-state operation includes steady-state operation having a speed not exceeding 1400 RPM.

[0265] Aspect 88. According to the method of aspect 87, the low-speed steady-state operation includes steady-state operation with a speed not exceeding 1200 RPM.

[0266] Aspect 89. According to the method of aspect 88, the low-speed steady-state operation includes steady-state operation with a speed not exceeding 1000 RPM.

[0267] Aspect 90. An intake system for delivering ambient air to an intake manifold of a low-compression internal combustion engine, the intake system comprising: a front boundary and an opposing rear boundary arranged along a first axis; an intake-side boundary and an opposing exhaust-side boundary arranged along a second axis, wherein the second axis is perpendicular to the first axis, and a compartment is defined by a combination of the front boundary, the rear boundary, the intake-side boundary, and the exhaust-side boundary. The low-compression internal combustion engine is disposed within the compartment such that a turbocharger is arranged along the first axis toward the front boundary and along the second axis toward the exhaust side; and a supercharger is disposed along the first axis behind the turbocharger and along the second axis toward the intake side.

[0268] Aspect 91. The intake system according to aspect 90 further includes a bypass line configured to bypass the turbocharger, wherein the bypass line is arranged along a first axis behind the turbocharger and centrally arranged along a second axis.

[0269] Aspect 92. The intake system according to aspect 91, wherein the bypass line is further configured to bypass the intercooler.

[0270] Aspect 93. The intake system according to aspect 92, wherein the intercooler is downstream of the turbocharger.

[0271] Aspect 94. The intake system according to aspect 93, wherein the intercooler is arranged along a first axis and centrally along a second axis at the rear boundary of the compartment.

[0272] Aspect 95. An intake system according to any one of Aspects 92-94, wherein the intercooler is upstream of the turbocharger.

[0273] Aspect 96. The intake system according to aspect 95, wherein the intercooler is arranged along a first axis behind the turbocharger and centrally arranged along the second axis.

[0274] Aspect 97. An intake system according to any one of Aspects 91-96, wherein the front boundary coincides with the outer casing boundary.

[0275] Aspect 98. According to any of aspects 91-97, the intake system is provided with a top boundary and an opposite bottom boundary along a third axis, the third axis being perpendicular to each of the first and second axes.

[0276] Preferred aspects and implementations of this disclosure have been described, and modifications and equivalents of the disclosed concepts will readily conceive of those skilled in the art. However, it is intended that such modifications and equivalents be included within the scope of the appended claims.

Claims

1. An intake system for a low compression ratio internal combustion engine, the system comprising: Turbocharger; A supercharger is located downstream of the turbocharger. A first intercooler is located between the turbocharger and the supercharger; as well as The second intercooler is located downstream of the turbocharger.

2. The system according to claim 1, wherein, The turbocharger is a clutch-type turbocharger.

3. The system according to claim 2, wherein, The clutch-type turbocharger includes an integrally formed clutch.

4. The system according to claim 2 or 3 further includes an acceleration device connected to the clutch-type supercharger.

5. The system according to any one of claims 1 to 4, wherein, The booster is constructed from an aluminum rotor.

6. The system according to any one of claims 1 to 5, further comprising: The turbocharger bypass line diverts the flow around the turbocharger during drive operation.

7. The system according to claim 6, wherein, The turbocharger bypass line diverts 100% of the flow from the turbocharger inlet to the inlet of the second intercooler.

8. The system according to claim 6 or 7 further includes a bypass throttle valve in the booster bypass line.

9. The system according to any one of claims 1 to 8, further comprising: The brake recirculation line extends from a location downstream of the second intercooler to a location between the first intercooler and the turbocharger.

10. The system according to claim 9, further comprising: A turbocharger bypass line that diverts flow around the turbocharger during drive operation, wherein the diameter of the turbocharger bypass line is larger than the diameter of the brake recirculation line.

11. The system according to claim 10, wherein, The brake recirculation line is a rubber hose.

12. The system according to any one of claims 9 to 11, further comprising a recirculation throttle valve in the brake recirculation line.

13. The system according to any one of claims 1 to 12, wherein, The turbocharger is a pulley-driven turbocharger, a gear-driven turbocharger, or an electric motor-driven turbocharger.

14. The system according to claim 13, wherein, The turbocharger is a two-speed turbocharger.

15. The system according to any one of claims 1 to 14, wherein, The second intercooler discharges gas into the intake manifold of the low-compression internal combustion engine.

16. A method of operating an intake system for an internal combustion engine, the intake system comprising a turbocharger, a first intercooler, a supercharger, and a second intercooler connected in series, the method comprising: The intake system is operated to support the internal combustion engine in braking mode by closing the throttle valve in the turbocharger bypass line; as well as The intake system is operated to support the internal combustion engine in drive mode by selectively operating the throttle valve in the turbocharger bypass line according to load conditions, wherein the throttle valve is fully open when the load conditions are low load conditions.

17. The method according to claim 16, wherein, The load condition is met when the engine load is less than 50%.

18. The system according to claim 16 or 17, wherein, Operating the intake system to support the internal combustion engine in the braking mode further includes directing airflow from the outlet of the second intercooler to the inlet of the turbocharger by opening a second throttle valve in the brake recirculation line.

19. The method according to any one of claims 16 to 18, wherein, The turbocharger is a clutch-type turbocharger.

20. The method according to claim 19, wherein, Operating the intake system to support the internal combustion engine in the drive mode further includes: operating the clutch to put the turbocharger in neutral when the throttle valve in the turbocharger bypass line is open.

21. The method according to claim 19 or 20, wherein, Operating the intake system to support the internal combustion engine in the braking mode further includes operating the clutch to connect the turbocharger to the acceleration device.

22. The method according to any one of claims 16 to 21, wherein, The turbocharger is a motor-driven turbocharger, and the motor of the motor-driven turbocharger has at least two speeds; Operating the intake system to support the internal combustion engine in the drive mode further includes: running the electric motor at a first speed; and The operation of the intake system to support the internal combustion engine in the braking mode further includes: operating the electric motor at a second speed, wherein the second speed is greater than the first speed.

23. The method according to any one of claims 16 to 22, wherein, The internal combustion engine is a hydrogen internal combustion engine.

24. The method according to any one of claims 16 to 23, wherein, During the driving mode, the second intercooler has an outlet temperature of less than or equal to 50°C, more preferably less than or equal to 40°C, and even more preferably less than or equal to 30°C.

25. The method according to claim 24, wherein, During the drive mode, when the throttle valve in the turbocharger bypass line is closed and the turbocharger is engaged, the first intercooler has an outlet temperature of less than or equal to 50°C, and more preferably less than or equal to 40°C, and even more preferably less than or equal to 30°C.

26. An intake system for an internal combustion engine, the system comprising: The turbocharger, the first intercooler, the supercharger, and the second intercooler are arranged in series and located in the engine compartment, such that: The second intercooler is located at the rear boundary of the engine compartment; The first intercooler is located in front of the first intercooler; as well as The turbocharger and each of the turbochargers are located in front of the second intercooler.

27. The intake system of claim 26 further includes a turbocharger bypass line disposed between the first intercooler and the turbocharger.

28. The intake system according to claim 26 or 27, wherein, The first intercooler is larger than the second intercooler.

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