Yuchai Co., Ltd. develops the world’s first high-pressure direct-injection pure ammonia internal combustion engine for heavy-duty commercial vehicles

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On April 26, the mid-term meeting of the **key research and development program “Development and Application of Key Technologies for Ammonia Engines Dedicated to Hybrid Heavy-Duty Commercial Vehicles”**, led by Yuchai Co., Ltd., was held in Changshu, Jiangsu. The first pure ammonia (single-ammonia-fuel) prototype developed under the project was successfully ignited and operated stably. It is the world’s first high-pressure direct-injection pure ammonia internal combustion engine for heavy-duty commercial vehicles. This marks a historic breakthrough for Yuchai in the field of zero-carbon power, as it has achieved both the coordinated operation with a high-pressure ammonia-to-hydrogen production system and the practical validation of the technology involving pre-chamber jet ignition for high-pressure direct injection of liquid ammonia. This internal combustion engine incorporates numerous key advanced core technologies, including a domed combustion chamber, an active pre-combustion chamber, high-pressure direct injection of liquid ammonia into the cylinder, coupled post-treatment for the conversion of multi-nitrogen-based products at low temperatures and with high efficiency, as well as intelligent control of the synergistic injection of multi-hydrogen-based fuels. Its thermal efficiency matches that of the most efficient existing heavy-duty diesel engines. This engine represents a novel zero-carbon power solution for heavy-duty long-distance commercial vehicles, balancing advantages in life-cycle costs with the requirements for low-carbon emissions; it thus facilitates the transition of traditional internal combustion engines toward green and zero-carbon operations. In terms of controllers, the project specifically developed a controller for hybrid ammonia internal combustion engines, filling the gap in Yuchai’s ability to develop proprietary core control software for such engines. This self-developed controller is equipped with a high-computational-power multi-core processor and a high-capacity storage module. Its core control logic is fully under proprietary control, enabling precise regulation of the pre-combustion chamber ignition, as well as the injection of ammonia-hydrogen mixtures and liquid ammonia. This significantly enhances Yuchai’s core competitiveness in the field of zero-carbon internal combustion engines. The ammonia-to-hydrogen system utilized in this ignition employs a technical approach involving catalytic cracking under high pressure to produce hydrogen, thereby overcoming the technological barriers to efficient catalytic conversion of ammonia into hydrogen under low-temperature and high-pressure conditions. The system is equipped with a new type of low-temperature ruthenium-based catalyst, which enables efficient hydrogen production from ammonia at low temperatures ranging from 400°C to 450°C. This significantly reduces the energy consumption and high-temperature losses associated with hydrogen production in the equipment. In recent years, Yuchai has been making continuous efforts in the field of low-carbon and zero-carbon power, achieving breakthroughs across the entire value chain from hydrogen energy and ammonia energy to methanol power. In the field of hydrogen energy, we have successfully developed YCK16H, the domestic engine with the largest displacement capable of running on hydrogen, and completed its demonstration operation in vehicles. Additionally, we have mastered PEM hydrogen production technology and launched a 30kW-class high-efficiency electrolyzer ； In the ammonia energy sector, we delivered China’s first ammonia-dual-fuel low-speed engine, the 6X52DF-A-1.0, marking China’s ship propulsion industry’s entry into the zero-carbon shipping arena ； In terms of methanol power, we have overcome the technical challenge of methanol’s poor ignitability. As a result, we have launched the highest-power spark-ignition single-methanol engine in China, which has also received certification from classification societies. In addition, Yuchai has developed a flexible fuel technology platform to provide core power support for multi-energy transportation. Yuchai stated that in the future, it will actively respond to the **“dual carbon” strategy** by making comprehensive efforts in the research and development of zero-carbon power technologies. It will continue to advance at the forefront of power technology innovation. With independent research and development as its core, the company aims to establish a complete intellectual property system for hybrid ammonia internal combustion engines. Furthermore, Yuchai is committed to building innovative R&D capabilities in the field of ammonia energy applications. Together with its partners, it seeks to create a full-chain demonstration ecosystem for ammonia energy applications in transportation, thereby contributing to the optimization of China’s transportation structure and the attainment of the “dual carbon” goals.