Development of Ammonia Direct Injection 4-Cylinder Spark-Ignition Engine 2024-01-2818

As the carbon neutrality to reduce greenhouse gas emissions has become a global movement, the development of power sources using carbon-free fuels is an essential task for the industry. Accordingly, many companies in various fields that need carbon reduction are striving to develop power sources and build energy value chains using carbon-free or carbon-neutral fuels such as hydrogen and E-fuel. Ammonia, which is also a carbon-free fuel, stands as an efficient energy vector delivering high energy density and flexibility in transportation and storage, capable of mitigating hydrogen’s key drawbacks. However, difficulty of controlling combustion of ammonia due to its fuel characteristics limited the development of internal combustion engines using ammonia to the basic research stage in the limited operating conditions. Hyundai Motor Company presents the development of ammonia fueled 4-cylinder SI engine using direct injection strategy, designed based on 2.5L LPG T-DI engine. It is the first multi-cylinder engine using liquefied ammonia direct injection fuel system (DI), making it possible to meet the performance and efficiency targets by overcoming the low air-fuel ratio characteristic of ammonia. Many other improvements were also carried out by design changes, hydrogen addition, and control optimization to overcome the low flame propagation speed of ammonia. Basic performance evaluation was carried out in all operating ranges of the engine, showing the potential of ammonia fueled carbon-free internal combustion engine as an alternative energy source for vehicles and power generations.