In the last issue, we talked about the application of hydrogen energy in the field of transportation, which is mainly completed by hydrogen fuel cells and hydrogen internal combustion engines, and in this issue, we will introduce the technical composition, R&D progress, and application scenarios of hydrogen internal combustion engines.
1. Composition of hydrogen internal combustion engine technologyTechnological progress in fuel cells, internal combustion engines and hybrid powertrains over the past 20 years has enabled hydrogen internal combustion engines to make full use of the existing industrial base and promote their application in vehicle power. Compared with other internal combustion engines, the cost advantage of hydrogen-fueled internal combustion engines will help increase the demand for hydrogen use and promote the construction of hydrogen infrastructure.
Hydrogen internal combustion engine stroke (Figure**: Yundian Daolin's "2023 China Hydrogen Energy Industry - Hydrogen Application In-depth Research Report") Hydrogen internal combustion engine refers to the replacement of gasoline, diesel, natural gas, methanol and other fuels in the traditional internal combustion engine with hydrogen, and the hydrogen is burned in the cylinder to push the piston to do work to generate kinetic energy, the principle is similar to that of ordinary natural gas engines, and the hydrogen injection system is added, and the conversion of chemical energy to mechanical energy is completed according to the 4 strokes of suction - compression - work - exhaust.
Hydrogen internal combustion engine working cycle (Figure**: Yundian Daolin's "2023 China Hydrogen Energy Industry - In-depth Research Report on Hydrogen Application Links").
Compared to hydrogen fuel cells,Hydrogen internal combustion engines do not require high purity of hydrogen, and have the characteristics of low ignition energy, fast flame propagation, high unit calorific value, and no carbon in combustionIt is suitable for high-load operation, so it is suitable for heavy trucks, buses, etc.
2. R&D route of hydrogen internal combustion engine technology in ChinaThe research and development of hydrogen internal combustion engine technology is based on the past fuel cell and hybrid powertrain, and the research and development of hydrogen engine in China began in the early 80s of the 20th century, and the research and development has accelerated in the past two years. 
Research and development of hydrogen internal combustion engine technology (Figure**: Yundian Daolin's "2023 China Hydrogen Energy Industry - In-depth Research Report on Hydrogen Application Links") In 2022, domestic enterprises will compete to launch hydrogen internal combustion engines in the field of heavy-duty commercial vehicles, among which the more prominent ones include Yuchai with the largest displacement, and Weichai and Sinotruk took the lead in realizing commercial application, and the liberating thermal efficiency exceeded 55%. 
In 2022, domestic car companies will make breakthroughs in the research and development of hydrogen internal combustion engines (Figure**: Yundian Daolin's "2023 China Hydrogen Energy Industry - In-depth Research Report on Hydrogen Application Links").3. Advantages of hydrogen internal combustion engineConsidering factors such as cost, performance, and reliability, hydrogen internal combustion engines have advantages over other fuel cells in the medium and long term.
Hydrogen internal combustion engines can be developed using the existing internal combustion engine industrial system, and most of the components are common to existing mature internal combustion engine products such as gasoline engines and natural gas enginesIt retains the main architecture and system of the traditional internal combustion engine, does not need to rebuild the industrial chain, can greatly shorten the development cycle, reduce the technical difficulty and cost investment, and is more conducive to the industrialization transformation
In addition, hydrogen internal combustion engines have the advantages of fast hydrogen refueling and no range anxiety, and have higher application potential in commercial vehicles in all fields
The hydrogen internal combustion engine adopts the traditional combustion work mode, which has lower requirements for the purity of hydrogen fuel, and has a higher comprehensive efficiency in the heavy-duty trucks and high-load vehicles that undertake goods, which is a more economical and efficient choice. In addition, hydrogen internal combustion engines have a variety of fuel adaptability, can use pure hydrogen as fuel, can also be blended with methanol, effectively reduce dependence on oil, one of the important means to implement the "double carbon" goal.
4. Application scenarios of hydrogen internal combustion enginesThe application fields of hydrogen internal combustion engines mainly include heavy trucks and ships, because methanol reforming hydrogen production and hydrogen power generation routes have been used in ship industrialization and gradually entered the mass production stage, we will leave it to the next issue to introduce it separately, and this issue only introduces the application scenarios of heavy trucks. In the application of heavy trucks, for long-distance transportation scenarios, through accounting and comparative analysis, pure hydrogen internal combustion engine and fuel cell technology route are the most competitive, pure hydrogen internal combustion engine cost cycle will be about 2025 and diesel vehicles "equal", fuel cells will have economic advantages over diesel vehicles after 2030. Pure electric and plug-in hybrid technologies are relatively competitive with diesel vehicles for a certain period of time, but the further they develop, the weaker their competitiveness will be compared with hydrogen internal combustion engines and fuel cell technologies.
Hydrogen internal combustion engine heavy truck power technology path (Figure**: Yundian Daolin's "2023 China Hydrogen Energy Industry - Hydrogen Application In-depth Research Report").
Therefore, from the perspective of the long-term development path,The future technology route of long-distance transportation scenarios will be dominated by diesel and natural gas by 2030Hydrogen internal combustion engine technology is complementaryThe period from 2030 to 2040 is the stage of coexistence and development of multiple technology routesAfter 2040, fuel cells and hydrogen internal combustion engines will be the mainstay, and natural gas and diesel will coexist in small amounts. (The content of this article is an excerpt from the author's report on Yundian Daolin's "2023 China Hydrogen Energy Industry - Hydrogen Application In-depth Research Report" and the author's personal views during the reading process. ）