Transonic Combustion focuses on the development of fuel injection systems for internal combustion engines. Its main product is a Fuel Injection System that allows injection of heated fuel up to a supercritical state, which is intended to improve engine efficiency and reduce emissions. The company serves the automotive and aerospace industries. It was founded in 2006 and is based in Camarillo, California.

Tour Engine is involved in the development of internal combustion engines for the power generation and mobility sectors. Their main offering is a split-cycle engine that utilizes thermal management to enhance fuel efficiency and reduce emissions. The company also provides a combined heat and power system, Tour ENABLE, which is designed to power microgrids and integrate renewable biofuels while reducing CO2 emissions. It was founded in 2005 and is based in San Diego, California.

Achates Power focuses on the development of opposed-piston engine technology within the transportation sector. The company provides engines for various applications, including passenger and commercial vehicles, military, and off-road power generation, with an emphasis on fuel efficiency and emissions compliance. It was founded in 2004 and is based in San Diego, California.

GoTek Energy develops rotary internal combustion engines for various transportation and stationary power generation sectors. The company offers products including rotary engines that operate on clean and standard fuels, as well as compressors and pumps for industrial applications. GoTek Energy serves the OEM and aftermarket sectors with its rotary technology. It was founded in 2011 and is based in Oxnard, California.

Tenneco focuses on manufacturing and distributing products for the transportation industry, including original equipment and aftermarket solutions. It offers services such as emissions control systems, engine components, and performance improvements for vehicles. It primarily serves sectors such as light vehicles, commercial trucks, and off-highway vehicles. Tenneco was formerly known as Tenneco Automotive. It was founded in 1930 and is based in Northville, Michigan.

Precision Combustion, Inc. develops and manufactures catalytic devices and systems for applications in the energy sector. The company produces products for power generation, emissions control, and chemical manufacturing, including fuel processors, solid oxide fuel cell systems, and air cleaning technologies. Precision Combustion serves sectors such as aerospace, defense, automotive, and indoor air quality. It was founded in 1986 and is based in North Haven, Connecticut.