An example of this is Sturman Industries' ADAPT system, which combines electronic fuel delivery, VVA air control, air-injection emission control, and a digital-hydraulic approach to a free-piston engine
developer of the long-stroke free-piston engine
and Sprague gear transmission that are licensed to Green Well Power the world's leading company in oil and gas / geothermal co-production, which recently signed a multi-million dollar project financing deal with Free Green Energy of Houston for the conversion of 200 end-of-life oil and gas wells into long-life electrical power generators expected to cost $280 million.
The company designs and builds a proprietary line of long-stoke, free-piston engines
and permanent magnet linear alternators.