CVCC

CVCC is a trademark by the Honda Motor Company for an engine with reduced automotive emissions, which stood for "Compound Vortex Controlled Combustion". The first mention of Honda developed CVCC technology was done by Mr. Soichiro Honda February 12, 1971, at the Federation of Economic Organizations Hall in Otemachi, Chiyoda-ku, Tokyo. Honda's engineers at the time, Mr. Date conferred with Mr. Yagi and Mr. Nakagawa about the possibility of creating lean combustion via a prechamber, which some diesel engines utilized. The first engine to be installed with the CVCC approach for testing was the single-cylinder, 300 cc Honda EA engine used in the Honda N600 hatchback in January 1970. This technology allowed Honda's cars to meet Japanese and United States emission standards in the 1970s without a catalytic converter. A type of stratified charge engine, it first appeared on the 1975 ED1 engine. As emission laws advanced and required more stringent admissible levels, Honda abandoned the CVCC method and introduced PGM-FI, or Programmed Fuel Injection on all Honda vehicles. Some vehicles in Japan had a combination of electronically controlled carburetors, called PGM-Carb on specific, transitional Honda D, E and ZC engines.

Toyota briefly used a similar technology in the mid-to-late seventies, called TTC-V. In 2007, the Honda CVCC technology was added to the Mechanical Engineering Heritage of Japan.

Honda CVCC engines have normal inlet and exhaust valves, plus a small auxiliary inlet valve which provides a relatively rich air–fuel mixture to a volume near the spark plug. The remaining air–fuel charge, drawn into the cylinder through the main inlet valve, is leaner than normal. The volume near the spark plug is contained by a small perforated metal plate. Upon ignition flame fronts emerge from the perforations and ignite the remainder of the air–fuel charge. The remaining engine cycle is as per a standard four-stroke engine.

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