High-efficiency hydrogen fuel low-temperature high-pressure storage and conveying system for internal combustion engine

Abstract

The invention relates to the technical field of new energy automobiles, and discloses a high-efficiency hydrogen fuel low-temperature high-pressure storage and delivery system for an internal combustion engine, which comprises a low-temperature pressurized hydrogen storage tank for minimizing heat exchange between hydrogen and an external environment, and an adiabatic expansion machine equipped with an air inlet valve and an air outlet valve, the input end of the adiabatic expander is communicated with the input end of the adiabatic expander and used for reducing the high pressure of hydrogen to intermediate pressure, the input end of the constant-volume heating chamber is communicated with the output end of the adiabatic expander and used for heating the hydrogen entering the constant-volume heating chamber, and the pressure of the hydrogen is increased through the constant-volume heating process. By arranging the low-temperature pressurizing hydrogen storage tank with a heat insulation function, matching with the heat insulation expander / compressor capable of adjusting the hydrogen pressure as required and the constant-volume heating chamber capable of converting heat energy into pressure, high-efficiency recovery and utilization of low-pressure hydrogen in the hydrogen storage tank are realized, and meanwhile, the hydrogen storage efficiency per unit volume is improved.

Description

Technical Field

[0001] This invention relates to the field of new energy vehicle technology, specifically to a high-efficiency hydrogen fuel cryogenic high-pressure storage and transportation system for internal combustion engines. Background Technology

[0002] With the increasing global demand for clean alternative energy, hydrogen energy, with its advantages of zero carbon emissions and high energy density, is being increasingly applied in the automotive power sector. As a core component of hydrogen-powered vehicles, the performance of the hydrogen fuel delivery system directly determines the vehicle's range, operating efficiency, and safety. Currently, hydrogen fuel delivery technologies in the industry are mainly divided into two categories: one is the high-pressure ambient temperature hydrogen storage and delivery system used in hydrogen fuel cell vehicles (such as the Toyota Mirai), and the other is the non-insulated ambient temperature hydrogen storage and simple pressure reduction delivery system used in traditional hydrogen fuel cell internal combustion engines. The hydrogen storage and delivery systems of existing hydrogen fuel cell vehicles are mostly designed with non-insulated hydrogen storage tanks. When fully charged, they store hydrogen at high pressure. When needed, a pressure regulation system reduces the pressure from high pressure to the low operating pressure required by the fuel cell stack, ensuring stable electrochemical reactions. In contrast, traditional hydrogen fuel cell internal combustion engines typically rely on non-insulated, ambient-temperature hydrogen storage tanks with simple pressure-reducing valves. They mechanically regulate the hydrogen pressure to a level suitable for the engine, meeting basic combustion requirements, but this is insufficient to meet the high efficiency, energy saving, and long range demands of hydrogen-powered vehicles. Therefore, this invention proposes a high-efficiency hydrogen fuel cryogenic high-pressure storage and transportation system for internal combustion engines to address the shortcomings of existing technologies. Summary of the Invention

[0003] The purpose of this invention is to provide a high-efficiency hydrogen fuel cryogenic high-pressure storage and transportation system for internal combustion engines, in order to solve the problems mentioned in the background art.

[0004] The objective of this invention can be achieved through the following technical solutions: A high-efficiency cryogenic high-pressure hydrogen fuel storage and transportation system for internal combustion engines, characterized in that it comprises: Cryogenic pressurized hydrogen storage tanks are used to minimize heat exchange between hydrogen and the external environment; An adiabatic expander, equipped with inlet and outlet valves, for reducing the high pressure of hydrogen to an intermediate pressure; A constant-volume heating chamber, the input end of which is connected to the output end of the adiabatic expander, is used to heat the hydrogen entering the chamber and increase the hydrogen pressure through a constant-volume heating process.

[0005] Preferably, the adiabatic expander is preset with a pressure threshold, when the hydrogen pressure discharged from the hydrogen storage tank exceeds the pressure threshold, the adiabatic expander operates in the expansion mode to reduce the hydrogen pressure; When the hydrogen pressure discharged from the hydrogen storage tank does not exceed the pressure threshold, the adiabatic expander switches to the compression mode to increase the hydrogen pressure.

[0006] Preferably, the delivery system alternately performs adiabatic expansion and constant-volume heating to achieve the required pressure and temperature for delivery, and the process of alternately performing adiabatic expansion and constant-volume heating is as follows: After the hydrogen is discharged from the hydrogen storage tank, the hydrogen is first subjected to adiabatic expansion in the adiabatic expander and then subjected to constant-volume heating in the constant-volume heating chamber. After the hydrogen is discharged from the hydrogen storage tank, the hydrogen is first subjected to constant-volume heating in the constant-volume heating chamber and then subjected to adiabatic compression in the adiabatic expander.

[0007] Preferably, the adiabatic structure of the low-temperature pressurized hydrogen storage tank is a multilayer vacuum adiabatic structure, and the multilayer vacuum adiabatic structure comprises aluminum foil barrier layers and glass fiber core materials arranged alternately.

[0008] Preferably, the adiabatic structure of the low-temperature pressurized hydrogen storage tank is used to maintain the low-temperature storage state of the hydrogen, and the pressure and temperature of the hydrogen change in accordance with the adiabatic process when the hydrogen is discharged from the hydrogen storage tank.

[0009] Preferably, the constant-volume heating chamber increases the temperature of the hydrogen to the ambient temperature through the constant-volume heating process, and the hydrogen pressure increases synchronously with the increase in the temperature.

[0010] Preferably, the constant-volume heating chamber heats the hydrogen under constant volume conditions, increases the hydrogen pressure through heat energy conversion, and makes the hydrogen reach the delivery pressure suitable for the injector.

[0011] The beneficial effects of the present application are as follows: 1. The present application sets a low-temperature pressurized hydrogen storage tank with adiabatic function, matches an adiabatic expander / compressor that can adjust the hydrogen pressure as required, and a constant-volume heating chamber that can convert heat energy into pressure, realizes the efficient recovery and utilization of low-pressure hydrogen in the hydrogen storage tank through the thermodynamic process of adiabatic expansion / compression and constant-volume heating, improves the hydrogen storage efficiency per unit volume, and finally solves the core problem that the low-pressure hydrogen cannot be utilized due to the high minimum available pressure threshold in the prior art, causing fuel waste and restricting the vehicle's endurance.

[0012] Of course, any product implementing the present application does not necessarily need to achieve all the advantages described above at the same time. BRIEF DESCRIPTION OF DRAWINGS

[0013] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the description of the embodiments. Obviously, the drawings described in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative effort on the basis of these drawings.

[0014] Fig. 1 A module block diagram of the present application is a high-efficiency hydrogen fuel low-temperature high-pressure storage and delivery system for internal combustion engines.

[0015] Fig. 2 A thermodynamic state change diagram of hydrogen of the present application is a high-efficiency hydrogen fuel low-temperature high-pressure storage and delivery system for internal combustion engines. DETAILED DESCRIPTION

[0016] The technical solutions in the embodiments of the present application will be described clearly and completely in the following with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present application.

[0017] Please refer to Figs. 1-2 As shown in the drawings, the present application is a high-efficiency hydrogen fuel low-temperature high-pressure storage and delivery system for internal combustion engines, which includes a hydrogen storage system: maximum pressure: when full, the hydrogen storage tank stores gas at high pressure, up to 700 bar, minimum usable pressure: when the pressure is lower than 20 bar, the fuel cell system cannot operate efficiently, at this time, the vehicle system will display that the hydrogen storage tank is empty, although there is still low-pressure hydrogen gas remaining, if the hydrogen storage tank is completely emptied, the pressure can reach 0 bar, but 20 bar is considered to be the minimum functional pressure for efficient hydrogen utilization, pressure regulation: high pressure to low pressure: hydrogen stored at 700 bar is reduced to the working pressure of the fuel cell stack, usually between 1 and 5 bar, a pressure reduction system ensures that hydrogen is delivered at a lower, safe working pressure, while maintaining efficiency and stable flow.

[0018] Reason for minimum pressure setting: Regulators are designed to function optimally within a specific pressure range, and if the input pressure is too low, near 1-5 bar, the regulator efficiency can decrease, leading to unstable hydrogen flow to the fuel cell. A minimum pressure of 20 bar ensures stable delivery, and maintaining a minimum pressure of 20 bar provides a safety buffer to prevent the fuel cell from experiencing a hydrogen supply shortage, which can lead to system damage or potential safety risks. This buffer also helps prevent air or contaminants from entering the system. While fuel cells can operate efficiently at lower pressures, 1-5 bar, delivering hydrogen at such low pressure directly from the hydrogen storage tank can lead to flow rate fluctuations, negatively impacting performance. A minimum pressure of 20 bar ensures more consistent and reliable flow, even though there is still hydrogen in the storage tank at 20 bar, the amount is not sufficient to significantly extend the vehicle's range. Therefore, the empty tank indication is set at 20 bar to provide an accurate and reliable estimate of the remaining fuel.

[0019] Cooling and temperature regulation: When hydrogen is delivered from high-pressure storage, up to 700 bar, to the low-pressure fuel cell, it undergoes expansion. However, hydrogen is an exception to the Joule-Thomson effect, which generally applies to other gases. For hydrogen, the inversion temperature under standard conditions is approximately 200 K, and the system manages temperature changes to prevent significant variations that could impact performance. Fuel cells operate at temperatures between 60°C and 85°C, and the temperature regulation system ensures that hydrogen is properly delivered to support optimal electrochemical reactions. Since the fuel tank is not insulated, and hydrogen is supplied at ambient temperature, this means that the storage capacity is reduced, and the cooling effect during expansion cannot be utilized, nor can the process of warming up to ambient temperature.

[0020] This innovative hydrogen fuel delivery system is designed specifically for internal combustion engines, using low-temperature pressurized hydrogen storage technology to provide high-pressure, typically 350 bar, but ambient-temperature hydrogen to the engine's injectors. The system effectively manages the extreme pressure and temperature fluctuations of hydrogen by combining adiabatic expansion / compression and isochoric heating, ensuring stable fuel delivery at high pressure for high-performance combustion while improving storage efficiency.

[0021] Adiabatic hydrogen storage: Hydrogen is initially stored in a cryogenic, adiabatic tank at high pressure, typically 700 bar, and low temperature, typically 120 K, designed to minimize heat exchange, keeping the hydrogen at high pressure and low temperature. During engine operation, as hydrogen is drawn from the tank, its density decreases, and pressure and temperature drop according to the adiabatic principle of real gases. This means that there is no heat exchange with the environment during this process. This results in a drop in temperature and pressure of the hydrogen as it leaves the storage tank, which helps to partially cool and expand the gas without energy loss to the surroundings. The density, pressure, and temperature within the storage tank are monitored. For adiabatic ambient temperature storage tanks and ambient pressure liquid hydrogen storage tanks, the venting requirement is very significant, but for non-adiabatic ambient temperature compressed gaseous hydrogen storage tanks, the requirement is greatly reduced. In this system, since the temperature and pressure drop as the tank is emptied, the venting requirement is primarily limited to when the tank is full, and, conversely, to prevent liquefaction of the hydrogen. Therefore, the hydrogen is heated to prevent the temperature from dropping below a threshold value, typically 35 K.

[0022] Adiabatic expander / compressor: After leaving the hydrogen storage tank, the hydrogen enters an adiabatic expander / compressor, which is a variable volume device with inlet and outlet valves. The expander is used to reduce the high pressure of the hydrogen to an intermediate pressure, while the temperature also drops according to the adiabatic process of real gases. If the hydrogen pressure is lower than the intermediate pressure, the compressor will start to increase the hydrogen pressure, ensuring stable delivery to the next stage of the system.

[0023] Constant volume heating chamber: After adiabatic expansion or compression, the hydrogen enters a constant volume chamber where it is heated to ambient temperature. During this isochoric heating process, as the temperature of the hydrogen increases to ambient temperature, its pressure also increases to the target delivery pressure, typically 350 bar, which is the ideal pressure for delivery to the ejector. To increase the work done and reduce the input work, the system can be further optimized by placing the isochoric heating process before the adiabatic expansion process, or by placing the adiabatic compression process before the isochoric heating process.

[0024] Cryogenic storage and low pressure utilization of hydrogen: This system is designed to store hydrogen efficiently, as the density of hydrogen at low temperature, typically 120 K, is much greater than at ambient temperature. In addition, the system is designed to use hydrogen even at lower tank pressures, typically as low as 5-10 bar, to more fully utilize the hydrogen stored on board the vehicle. The system takes advantage of the temperature drop effect during adiabatic expansion of real gases, as well as the pressure build-up effect during isochoric heating.

[0025] The hydrogen fuel delivery system utilizes advanced thermodynamic principles to effectively manage the dramatic pressure and temperature changes of hydrogen gas as it flows from a cryogenic, high pressure storage tank to the engine injectors. By combining the use of adiabatic expansion and compression, along with a constant volume heating chamber, the system is able to deliver hydrogen gas at high pressure, typically 350 bar, and ambient temperature, which are ideal operating conditions for advanced internal combustion engine combustion systems.

[0026] The main advantages include: higher storage efficiency compared to conventional systems that use non-adiabatic, ambient temperature hydrogen storage and simple pressure relief valves, as more hydrogen gas is stored in the adiabatic fuel tank at cryogenic temperatures, and the pressure is regulated with minimal energy loss through adiabatic and isochoric processes, allowing the use of high pressure direct injectors, typically 350 bar, suitable for advanced combustion strategies such as direct injection jet ignition, resulting in higher efficiency and cleaner combustion in hydrogen fuelled internal combustion engines, compared to conventional pressurized fuel systems, especially those designed for fuel cells, as the use of cryogenic storage and effective pressure management through adiabatic and isochoric transformations is allowed, ensuring improved performance and fuel economy for hydrogen-powered vehicles.

[0027] Hydrogen gas is stored in a cryogenic, pressurized tank at high pressure, for example 700 bar, and low temperature, for example 120 K, the tank is adiabatically treated to minimize heat exchange. When hydrogen gas leaves the storage tank, its pressure and temperature adiabatically decrease, this process creates an efficient cooling effect as the hydrogen gas leaves the tank, adiabatic expander / compressor: the hydrogen gas flows through an adiabatic expander, the pressure decreases from 700 bar or lower to a threshold pressure, the temperature also decreases accordingly. If the tank pressure falls below this threshold pressure, the compressor will start to increase the pressure, ensuring that the hydrogen gas is always delivered at a suitable pressure for the engine after the constant volume heating process, constant volume heating chamber: after decompression and cooling, the hydrogen gas enters a constant volume chamber where it is heated to ambient temperature. The pressure increases proportionally to the temperature. This heating process prepares the hydrogen gas for injection into the engine at high pressure, for example 350 bar, low pressure hydrogen utilization: the system ensures efficient utilization of hydrogen gas even at low pressure, for example 10 bar, as the compressor can raise the low pressure hydrogen gas to the desired high pressure, for example 350 bar, for delivery to the engine, ensuring maximum utilization of stored fuel and maximum efficiency of engine use, sequence of adiabatic and isochoric processes: adiabatic compression can be arranged after isochoric heating, and adiabatic expansion can be arranged before isochoric heating, to maximize output work and minimize input work.

[0028] By isochoric confinement of low-temperature hydrogen, efficient pressure build-up through heating, and seamless integration of thermodynamic processes for optimal hydrogen utilization, the system uses an isochoric chamber to heat and depressurize low-temperature hydrogen, increasing its pressure while maintaining a constant volume. Unlike traditional systems that rely solely on mechanical compression or simple expansion, this system converts thermal energy into pressure build-up, reducing the energy demand for mechanical compression. By heating the hydrogen to ambient temperature, the system achieves a significant pressure increase, for example, from approximately 10 bar to 350 bar, without the need for additional compression stages, ensuring efficient delivery to the ejector. Compared to simple mechanical compression, the system has lower energy consumption, providing stable delivery pressure for high-performance injection. Integration of adiabatic and isochoric processes, adiabatic expansion / compression: After leaving the cryogenic tank, hydrogen undergoes adiabatic expansion or compression. These processes minimize heat exchange with the environment, optimizing the thermodynamic efficiency of the system. Sequential thermodynamic processes: The system alternates between adiabatic expansion / compression and isochoric heating to achieve the required pressure and temperature for delivery, for example: Sequence 1: Adiabatic expansion followed by isochoric heating.

[0029] Sequence 2: Isochoric heating followed by adiabatic compression.

[0030] These sequences are fine-tuned to maximize work and minimize energy input. The flexible process sequence allows for optimization based on tank pressure and engine requirements, ensuring robust and adaptable performance. Low-temperature storage for increased hydrogen density: Hydrogen is stored at extremely low temperatures, for example, 120 K, and high pressures, for example, 700 bar. At low temperatures, the density of hydrogen is 67.781 kg / m 3 , significantly exceeding its density at ambient temperature, 39.237 kg / m 3 . This increase in density allows for the storage of more hydrogen mass per unit volume, improving vehicle range and efficiency. The increased density allows for the use of smaller, lighter tanks, improving vehicle range and efficiency. Low-temperature storage naturally supports adiabatic cooling during expansion, further improving system efficiency. The existing systems usually require a minimum pressure of e.g. 20 bar to operate, resulting in residual hydrogen in the tank that cannot be used. The present system utilizes a compressor to boost the hydrogen pressure even when the tank pressure drops to a low level of 5-10 bar, maximizing hydrogen utilization, reducing waste, extending vehicle range using the same initial amount of hydrogen, boosting performance with high pressure direct injection, supporting advanced combustion strategies such as direct injection jet ignition that require precise, high pressure hydrogen delivery, higher thermal efficiency, cleaner combustion, reduced nitrogen oxides, emissions, enhanced engine power output, minimized exhaust losses and prevention of liquefaction by maintaining stable pressure and temperature during storage and extraction, minimizing hydrogen exhaust losses by maintaining stable pressure and temperature during storage and extraction, fine temperature management prevents hydrogen from reaching the liquefaction threshold of ~35 K ensuring safe and stable operation, utilizing the natural cooling effect of adiabatic expansion, reducing the energy required for subsequent compression or heating, converting thermal energy into pressure boost, offsetting the mechanical work typically required for pressure regulation, the combination of adiabatic and isochoric processes ensures minimal energy losses while maintaining optimal delivery conditions.

[0031] The low temperature conditions allow for more hydrogen to be stored per volume compared to conventional systems, efficiently utilizing low pressure hydrogen, minimizing fuel residuals, isochoric heating reduces dependence on mechanical compression, stable high pressure delivery supports advanced combustion technologies, the novel combination of adiabatic and isochoric processes sets this system apart from existing hydrogen fuel delivery technologies.

[0032] The above merely provides an illustration of the basic concept of the present application. Those skilled in the art can make various modifications or additions to the specific embodiments described or adopt similar means to replace them without departing from the basic concept of the present application or exceeding the scope of the present application defined by the claims.

Claims

1. A high-efficiency cryogenic and high-pressure hydrogen fuel storage and transportation system for internal combustion engines, characterized in that, include: Cryogenic pressurized hydrogen storage tanks are used to minimize heat exchange between hydrogen and the external environment; An adiabatic expander, equipped with inlet and outlet valves, for reducing the high pressure of hydrogen to an intermediate pressure; A constant-volume heating chamber, the input end of which is connected to the output end of the adiabatic expander, is used to heat the hydrogen entering the chamber and increase the hydrogen pressure through a constant-volume heating process.

2. The high-efficiency hydrogen fuel cryogenic high-pressure storage and transportation system for internal combustion engines according to claim 1, characterized in that, The thermal expansion device is preset with a pressure threshold. When the pressure of the hydrogen flowing out of the hydrogen storage tank exceeds the pressure threshold, the thermal expansion device operates in expansion mode to reduce the hydrogen pressure. When the hydrogen pressure flowing out of the hydrogen storage tank does not exceed the pressure threshold, the adiabatic expander switches to compression mode to increase the hydrogen pressure.

3. The high-efficiency hydrogen fuel cryogenic high-pressure storage and transportation system for internal combustion engines according to claim 1, characterized in that, The conveying system alternately performs adiabatic expansion and constant-volume heating to achieve the required pressure and temperature for conveying. The process of alternating adiabatic expansion and constant-volume heating is as follows: After hydrogen flows out of the hydrogen storage tank, it first undergoes adiabatic expansion through an adiabatic expander, and then enters a constant volume heating chamber for constant volume heating. After hydrogen flows out of the hydrogen storage tank, it first enters the constant volume heating chamber for constant volume heating, and then passes through the adiabatic expander for adiabatic compression.

4. The high-efficiency hydrogen fuel cryogenic high-pressure storage and transportation system for internal combustion engines according to claim 1, characterized in that, The thermal insulation structure of the cryogenic pressurized hydrogen storage tank is a multi-layer vacuum thermal insulation structure, which includes alternating aluminum foil barrier layers and glass fiber core material.

5. A high-efficiency hydrogen fuel cryogenic high-pressure storage and transportation system for internal combustion engines according to claim 4, characterized in that, The thermal insulation structure of the cryogenic pressurized hydrogen storage tank is used to maintain the cryogenic storage state of hydrogen. When hydrogen flows out of the storage tank, the pressure and temperature of the hydrogen change according to the thermal insulation process.

6. A high-efficiency hydrogen fuel cryogenic high-pressure storage and transportation system for internal combustion engines according to claim 1, characterized in that, The constant-volume heating chamber raises the hydrogen temperature to ambient temperature through a constant-volume heating process, and the hydrogen pressure increases synchronously with the temperature increase.

7. A high-efficiency hydrogen fuel cryogenic high-pressure storage and transportation system for internal combustion engines according to claim 1, characterized in that, The constant-volume heating chamber heats hydrogen under constant volume conditions, so that the hydrogen reaches the delivery pressure suitable for the injector.

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