SwRI tackles pre-ignition challenges in hydrogen-fueled engines

SAN ANTONIO — November 26, 2025 — Engineers at Southwest Research Institute (SwRI) have developed a reliable testing methodology to study stochastic pre-ignition (SPI) in hydrogen-fueled internal combustion engines (H ₂ -ICEs), offering the automotive industry tools to address challenges associated with hydrogen fuel and advance cleaner engine technologies.

Pre-ignition, where unintentional combustion occurs before spark timing, is disruptive and sometimes detrimental to engine performance and durability. While hydrogen's low ignition threshold is a suspected SPI factor, SwRI explored whether lubricant autoignition contributes to SPI in H ₂ -ICEs.

“H ₂ -ICEs experience pre-ignition at higher frequencies than spark-ignited gasoline engines, although the events are milder compared to the intense SPI events observed in SI gasoline ICEs, which can cause severe mechanical damage,” said Dr. Vickey Kalaskar, lead engineer with SwRI’s Powertrain Systems Engineering Department. “The research conducted demonstrates that while additive chemistry appears to be the dominant driver for gasoline engine SPI, lubricant oil volatility and compression ratio are driving influences for hydrogen-fueled pre-ignition events.”

Through the course of this research, SwRI engineers developed a new testing methodology, which provides insight into lubricant-initiated SPI in H ₂ -ICEs and supports further work, such as refining SPI quantification methods, exploring mitigation strategies and evaluating commercial lubricants.

The research underlines SwRI’s leadership in hydrogen engine innovation, building upon initiatives like the Clean Highly Efficient Decarbonized Engines (CHEDE-9) program and the successful development of a fully functional H ₂ -ICE Class-8 truck. These efforts demonstrated advancements in H₂-ICE systems research with innovations such as SwRI’s fully functional H ₂ -ICE Class-8 truck. SwRI is also partnering with the University of Texas at San Antonio to integrate machine learning and AI for real-time pre-ignition detection in H ₂ -ICEs .

Kalaskar and his team will present their findings at the 2025 IAV Symposium on Pre-ignition, Auto-ignition, Reactivity and Knock (SPARK) on Dec. 2, 2025, in Detroit. This project was funded through the SwRI Internal Research and Development Program. In 2024, SwRI invested more than $11 million in tomorrow’s technology to broaden its knowledge base, expand its reputation as a leader in science and technology, and encourage its staff’s professional development. For more information, visit Southwest Research Institute Internal R&D .

For more information, visit https://www.swri.org/markets/automotive-transportation/automotive/hydrogen-powered-vehicles/hydrogen-internal-combustion-engine-2-h2-ice2-consortium .