ClearFlame Leadership Team

This team leads industry veterans and engineers who have collectively amassed over 400 years of experience crafting engines for market use for companies such as Cummins, Caterpillar, Ford, and Navistar.

Dr. BJ Johnson
Co-Founder & Chief Executive Officer

Dr. BJ Johnson is CEO and co-founder at ClearFlame Engine Technologies, a company dedicated to creating innovative solutions that rapidly decarbonize heavy-duty industries. ClearFlame’s technology uses various clean, renewable fuels to power diesel engines, reducing emissions and ownership costs and maintaining performance. BJ’s vision has attracted significant investors and strategic partners, including the Department of Energy, Mercuria, and Breakthrough Energy Ventures. In 2021, BJ was named to the Grist 50—a list of emerging leaders working on real-world solutions to the world’s biggest challenges. BJ earned his BS, MS, and Ph.D. in mechanical engineering from Stanford University.  

Dr. Julie Blumreiter
Co-Founder & Chief Technology Officer

Dr. Julie Blumreiter is Chief Technology Officer and Co-founder of ClearFlame Engine Technologies, a company dedicated to creating innovative solutions that rapidly decarbonize heavy-duty industries. She leads engineering research and development of ClearFlame’s engine modification technology, which powers heavy-duty engines with clean, renewable fuels. Julie earned her B.S. in mechanical engineering from Johns Hopkins University and both her M.S. and Ph.D. in mechanical engineering from Stanford University. She is a member of the Society of Women Engineers, SAE International and a contributing author of SAE’s award-winning book ‘Doing the Hard Work.’

Kirk Roller
Chief Operating Officer

As ClearFlame’s Chief Operating Officer, Kirk Roller leads strategies to guide the company’s continued growth in key market sectors and developing critical fleet, fuel, and service partnerships to support customer needs. He joined ClearFlame in 2021 as VP of business development, following more than 35 years in renewable energy and high-tech. Kirk previously held leadership roles in sales and marketing at Hyliion, Cenergestic and CommScope. As president and COO of Emulex, he grew the company’s market cap from $30 million to $7 billion. Kirk earned a BBA in business administration and management from the University of Texas at Austin.

Craig Barnes
Chief Product Officer

Craig Barnes is Chief Product Officer for ClearFlame, responsible for all product initiatives, including strategy, planning and implementation. An industry veteran, Craig’s career in the commercial vehicle and off-highway industries spans nearly 50 years. For 27 years he served in a variety of leadership roles at Cummins, most recently as CTO of both the company’s components business in the U.S. and before that, its operations in India. He began his career with John Deere overseeing engineering design and development. Craig is an active member and advisor for SAE International and earned his Bachelor of Science in Mechanical Engineering at the University of Missouri-Rolla (now the Missouri University of Science and Technology).

Dr. Cathy Choi
Chief Sustainability Officer and VP of Engineering

As Chief Sustainability Officer and Vice President of Engineering at ClearFlame, Cathy Choi oversees the company’s engineering development and execution of product launches while also ensuring that the company’s innovative engine technology is supporting critical sustainability targets. With more than three decades of energy and transportation experience, she joins ClearFlame from Cummins, where she led new technology strategy and development. She also previously supported business and technology strategy at Caterpillar, developing a global business strategy to meet net-zero greenhouse gas goals by 2050 and launching more than 100 low-emissions engines and their applications, generating $30 billion in business. Cathy earned her Ph.D. in Mechanical Engineering from UW— Madison, specializing in combustion and emissions formation and alternative fuels research.