Breakthrough in Chemicals and Chemistry: Oval Rotary Engine Harnesses Hydrogen Power

Researchers from the Beijing University of Technology have made significant advancements in the field of chemicals and chemistry, specifically in the development of an oval rotary engine (ORE) that utilizes hydrogen direct-injection spark-ignition. The innovative engine boasts variable compression ratio, fixed combustion chambers, and a simple seal structure, offering improved performance and efficiency. The research, funded by various institutions, has led to notable findings and statistics that shed light on the engine's capabilities and potential applications.

Key Takeaways:

• The oval rotary engine retains the Wankel rotary engine's smooth rotation and high power density while featuring variable compression ratio, fixed combustion chambers, and a simple seal structure.
• Numerical simulation studies reveal that the impact of intake and rotor wall movement on the flow field leads to two vorticity peaks in the intake stroke and before top dead center.
• Oxygen-enrichment solves the problem of slow combustion in atmospheric conditions but brings higher NOx emissions, while higher oxygen concentrations lead to decreased combustion efficiency and indicated thermal efficiency.
• Reduced injection pulse width results in a wider distribution of hydrogen during combustion, promoting combustion and improving combustion efficiency and indicated thermal efficiency, but leading to more NOx emissions.
• The optimal condition for the engine is achieved with oxygen concentration at 24% and injection pulse width at 12 degrees CA, resulting in improved combustion efficiency and indicated thermal efficiency by 6.7% and 3.4%, respectively.
• The engine's optimal condition also leads to a 0.3 mg per cylinder per cycle increase in NOx emissions.

Statistics:

• 24% oxygen concentration and 12 degrees CA injection pulse width result in a 6.7% improvement in combustion efficiency and a 3.4% increase in indicated thermal efficiency.
• The engine achieves a 0.3 mg per cylinder per cycle increase in NOx emissions under optimal conditions.
• The research results in improved combustion efficiency and indicated thermal efficiency by 6.7% and 3.4%, respectively, under initial atmospheric conditions.

Sources:

• "Effect of Injection Pulse Width On Hydrogen Direct-injection Oval Rotary Engine Under Different Oxygen-enriched Strategy." Energy, 2025; 328.
• NewsRx. Beijing University of Technology Reports Findings in Chemicals and Chemistry (Effect of Injection Pulse Width On Hydrogen Direct-injection Oval Rotary Engine Under Different Oxygen-enriched Strategy). Chemicals & Chemistry. August 8, 2025; p 199.
• Pergamon-Elsevier Science Ltd. The Boulevard, Langford Lane, Kidlington, Oxford OX5 1GB, England.
• Elsevier. www.elsevier.com.
• Beijing University of Technology. College of Mechanical and Energy Engineering. Beijing Lab New Energy Vehicles. Beijing 100124, People's Republic of China.