CVCC is a trademark by the Honda Motor Company for a device used to reduce automotive emissions called a Compound Vortex Combustion Chamber, and it allowed Honda's cars to meet the 1970s US Emission requirements without a catalytic converter. It is a form of Stratified charge engine.Honda CVCC engines have normal inlet and exhaust valves, plus a small auxilary 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.
This mix of rich mixture near the spark plug, and lean mixture in the cylinder allowed stable running yet complete combustion of fuel, thus reducing CO ( carbon monoxide) and hydrocarbon emissions.
Pronouncing "C.V.C.C" as a word gave the Honda Civic its name.
