Hydrogen engine system

Abstract

Provided is a hydrogen engine system in which energy efficiency is ensured and complexity and size increase are suppressed. This hydrogen engine system is provided with: a hydrogen engine that uses gaseous hydrogen as fuel; a tank that stores liquid hydrogen; a pump that pressure-feeds the liquid hydrogen to the hydrogen engine; and a vaporizer that converts the liquid hydrogen pressure-fed from the tank into gaseous hydrogen by heating and supplies the gaseous hydrogen to the hydrogen engine. A boil-off gas supply passage for supplying the boil-off gas in the tank to the vaporizer; and an oxygen supplier for supplying oxygen to the vaporizer. The vaporizer uses the heat of reaction between the boil-off gas supplied to the vaporizer and the oxygen as a heat source for heating the liquid hydrogen.

Description

Technical Field

[0001] This invention relates to hydrogen engine systems. Background Technology

[0002] A hydrogen engine system exists, comprising a hydrogen engine that uses gaseous hydrogen as fuel, a storage tank containing liquid hydrogen, a pump that pressurizes the liquid hydrogen to the hydrogen engine, and a vaporizer that heats the liquid hydrogen pressurized from the storage tank to change its state into gaseous hydrogen before supplying it to the hydrogen engine. For example, in the hydrogen engine system of Patent Document 1, the evaporated gas in the storage tank is used to generate electricity, and the warm water generated during power generation is supplied to the vaporizer as a heat source. Thus, energy efficiency is ensured by effectively utilizing the evaporated gas.

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2020-112236. Summary of the Invention The problem that the invention aims to solve

[0004] The hydrogen engine system described above requires a power generation device that uses evaporated gas to generate electricity, making the system more complex and larger.

[0005] Therefore, the object of the present invention is to provide a hydrogen engine system that ensures energy efficiency and suppresses the increasing complexity and size of the engine. Methods for solving problems

[0006] The above objective can be achieved by a hydrogen engine system comprising: a hydrogen engine fueled by gaseous hydrogen; a storage tank containing liquid hydrogen; a pump for pressurizing the liquid hydrogen to the hydrogen engine; a vaporizer for supplying the liquid hydrogen pressurized from the storage tank to the hydrogen engine by heating and converting it into gaseous hydrogen; an evaporation gas supply passage for supplying the vaporizer with evaporation gas from the storage tank; and an oxygen supplier for supplying oxygen to the vaporizer, wherein the vaporizer uses the heat of reaction between the evaporation gas supplied to the vaporizer and the oxygen as a heat source for heating the liquid hydrogen. Invention Effects

[0007] According to the present invention, a hydrogen engine system that ensures energy efficiency and suppresses the increasing complexity and size of existing systems can be provided. Attached Figure Description

[0008] Figure 1 This is a structural diagram of a hydrogen engine system. Detailed Implementation

[0009] Figure 1This is a structural diagram of the hydrogen engine system 1. In this embodiment, the hydrogen engine system 1 is mounted on a vehicle and includes a storage tank 10, a pump 20, a carburetor 30, a hydrogen engine 40, three-way valves 51, 52, 53, and 54, air compressors 61 and 62, a muffler 70, an ECU (electronic control unit) 100, and drive wheels 110. The power of the hydrogen engine 40 is transmitted to the drive wheels 110 via a transmission, thereby propelling the vehicle. The vehicle can be, for example, a hydrogen engine vehicle equipped only with the hydrogen engine 40 as its driving power source, or a hybrid vehicle equipped with both the hydrogen engine 40 and an electric motor as driving power sources. The hydrogen engine 40 is driven by burning gaseous hydrogen as fuel.

[0010] One end of pipe 81 is connected to pump 20, and the other end is connected to one end of heat exchanger 32 in vaporizer 30. One end of pipe 82 is connected to the other end of heat exchanger 32 inside vaporizer 30, and the other end is connected to three-way valve 53. One end of pipe 83 is connected to three-way valve 53, and the other end is connected to hydrogen engine 40. One end of pipe 84 is connected to the upper part inside storage tank 10, and the other end is connected to three-way valve 51. One end of pipe 85 is connected to three-way valve 51, and the other end is connected to three-way valve 52. One end of pipe 86 is connected to three-way valve 52, and the other end is connected to the lower part inside vaporizer 30. One end of pipe 87 is connected to three-way valve 52, and the other end is connected to three-way valve 53. One end of pipe 88 is connected to three-way valve 51, and the other end is connected to muffler 70. One end of pipe 91 is connected to hydrogen engine 40, and the other end is connected to three-way valve 54. One end of pipe 92 is connected to three-way valve 54, and the other end is connected to silencer 70. One end of pipe 93 is connected to three-way valve 54, and the other end is connected to vaporizer 30.

[0011] The ECU 100 is centered around a computer containing volatile and non-volatile memory such as a CPU (Central Processing Unit), RAM (Random Access Memory), and ROM (Read-Only Memory). The ECU 100 executes programs installed in memory on the CPU to perform various control processes related to the hydrogen engine system 1. Based on the preheating and operating status of the hydrogen engine 40, the ECU 100 controls the pump 20, three-way valves 51, 52, 53, and 54, and air compressors 61 and 62.

[0012] Tank 10 stores hydrogen in a liquid state. Pump 20 pressurizes the liquid hydrogen (LH2) stored in tank 10 to hydrogen engine 40. Vaporizer 30 heats the liquid hydrogen pressurized by pump 20 through pipe 81 to convert it into gaseous hydrogen (GH2), and supplies it to hydrogen engine 40 through pipes 82 and 83. As the liquid hydrogen flows through heat exchanger 32 (details to be described later), it is heated and converted into gaseous hydrogen. ECU 100 controls three-way valve 53 to supply gaseous hydrogen to hydrogen engine 40 through pipes 82 and 83.

[0013] The storage tank 10 is vacuum insulated, but due to heat input, the stored liquid hydrogen will naturally vaporize over time. The hydrogen produced by natural vaporization, i.e., the vaporized gas (BOG-H2), will remain in the upper part of the storage tank 10. The vaporized gas causes the internal pressure of the storage tank to rise. Therefore, when the hydrogen engine 40 stops, the ECU 100 uses the air compressor 61 to dilute the vaporized gas discharged through the three-way valve 51 via pipes 84 and 88 to the muffler 70 and release it into the atmosphere.

[0014] During the preheating process after the hydrogen engine 40 starts, the ECU 100 controls three-way valves 51 and 52 to introduce the evaporated gas into the carburetor 30 via pipes 84, 85, and 86. Pipes 84, 85, and 86 are an example of the evaporated gas supply passage. Furthermore, the ECU 100 uses an air compressor 62 to supply air into the carburetor 30, thereby supplying oxygen to the carburetor 30. The air compressor 62 is an example of an oxygen supplier. Thus, within the carburetor 30, oxygen (O2) from the air and hydrogen (H2) from the evaporated gas are agitated, and the hydrogen and oxygen react as follows to produce water and generate heat of reaction. 2H₂ + O₂ = 2H₂O + 286kJ

[0015] Using the aforementioned heat of reaction, the liquid hydrogen within the heat exchanger 32 is heated and transformed into gaseous hydrogen. This effectively utilizes the evaporated gas, ensuring energy efficiency. Furthermore, since the heat of reaction between oxygen in the air and the hydrogen in the evaporated gas is used to heat the liquid hydrogen, there is no need for a power generation device to generate electricity to transform the liquid hydrogen into gaseous hydrogen. This reduces the complexity and size of the hydrogen engine system 1.

[0016] Furthermore, a thermocouple 31 is installed within the vaporizer 30. The ECU 100 uses the thermocouple 31 to heat the gas within the vaporizer 30. This further promotes the reaction between hydrogen and oxygen. Utilizing the heat of reaction thus generated, the produced water becomes high-temperature water vapor. This, in turn, promotes the state change from liquid hydrogen to gaseous hydrogen within the heat exchanger 32. It should be noted that the reaction between hydrogen and oxygen is further promoted by using copper as a catalyst. Therefore, by employing copper wire for the thermocouple 31, the power consumption of the thermocouple 31 can be reduced.

[0017] When the carburetor 30 does not require evaporated gas, the ECU 100 controls three-way valves 51, 52, and 53 to supply evaporated gas to the hydrogen engine 40 via pipes 84, 85, 87, and 83. This improves fuel efficiency. Furthermore, when the hydrogen engine 40 starts and releases evaporated gas to the atmosphere, the ECU 100 controls three-way valve 54 to dilute the evaporated gas emitted to the muffler 70 using the exhaust gas from the hydrogen engine 40, which is discharged to the muffler 70 via pipes 91 and 92. This allows for dilution of the evaporated gas and release to the atmosphere even when the air compressor 61 is stopped, reducing power consumption.

[0018] Furthermore, after the hydrogen engine 40 has been fully preheated, the ECU 100 controls the three-way valve 54 to guide the exhaust gas from the hydrogen engine 40 into the carburetor 30 via pipes 91 and 93. This utilizes the heat from the exhaust gas to promote the change of state from liquid hydrogen to gaseous hydrogen, thereby improving fuel efficiency.

[0019] As described above, energy efficiency is ensured because the heat of reaction between oxygen in the air and hydrogen in the evaporated gas is used to change the state of liquid hydrogen to gaseous hydrogen. Furthermore, since there is no need for a power generation device to generate electricity to facilitate this state change, system complexity and size are reduced. Additionally, by using copper wire for the thermocouple 31, supplying evaporated gas to the hydrogen engine 40, diluting the evaporated gas with exhaust gas, and using exhaust gas to promote the state change from liquid hydrogen to gaseous hydrogen, power consumption can be reduced and fuel efficiency improved.

[0020] The embodiments of the present invention have been described in detail above, but the present invention is not limited to these specific embodiments. Various modifications and alterations can be made within the scope of the spirit of the present invention as set forth in the claims. Explanation of reference numerals in the attached figures

[0021] 1 Hydrogen Engine System

[0022] 10 storage tanks

[0023] 20 pumps

[0024] 30 vaporizer

[0025] 40 hydrogen engine

[0026] 62 Air compressor (oxygen supply unit)

[0027] Piping 84, 85, 86 (evaporation gas supply passage).

Claims

1. A hydrogen engine system, comprising: Hydrogen engines use gaseous hydrogen as fuel; Storage tank, containing liquid hydrogen; The pump pressurizes the liquid hydrogen into the hydrogen engine; A vaporizer converts the liquid hydrogen pressurized from the storage tank into gaseous hydrogen by heating, and supplies it to the hydrogen engine. The evaporation gas supply passage supplies the evaporation gas from the storage tank to the vaporizer; and An oxygen supplier supplies oxygen to the vaporizer. The vaporizer uses the heat of reaction between the evaporated gas and the oxygen supplied to it as a heat source for heating the liquid hydrogen.

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