Stoichiometric mixture: “If exactly enough air is provided to completely burn all of the fuel, the ratio is known as the stoichiometeric mixture”, wiki.
The Green Machine gasoline vapor system helps your fuel injected system provide a better stoichiometric mixture inside the combustion chamber, providing for a more complete burn of the fuel without leaning out the Air/Fuel ratio and creating Carbon Monoxide (CO). When all the fuel is burnt inside the chambers, the less heat is transferred to the metal helping the engine to maintain a proper operating temperature and reducing wear.
The Green Machine Vapor significantly reduces the amount of unburnt and half burnt fuel released into the atmosphere. More than EGR, Catalytic converters, and other emission technologies. Burn more fuel equals more horsepower and better mileage with cleaner emissions.