The Texaco Controlled-Combustion System, a stratified charge concept utilizing a coordinated arrangement of air swirl, fuel injection and positive ignition, has been shown over many years of development in numerous engine conversions to produce excellent fuel economy, inherently low exhaust emissions and the ability to prevent combustion knock without regard to fuel octane or cetane number. Recent work has demonstrated the capability of the system to meet the very stringent emission levels of the 1976 U.S. Federal Standards for light duty vehicles and the potential to maintain these levels during 50,000 miles of testing.