Emission Control Systems
Fuel Injection
The primary emission control is fuel injection. Fuel injection offers precise fuel control over a wide range of conditions. Feedback supplied by the exhaust gas oxygen sensor and various engine sensors allows the injection system to compensate for changes in atmospheric conditions (temperature, altitude, etc.) as well as mechanical conditions (such as state of tune, etc.).
Catalytic Converter
The catalytic converter effectively changes harmful pollutants into carbon dioxide and water.
Fill Pipe Restrictor
The fill pipe restrictor prevents the larger diameter fuel nozzles used for leaded fuels from entering the fill pipe. Leaded fuel will permanently contaminate the oxygen sensor, and the catalytic converter.
Positive Crankcase Ventilation (PCV)
The PCV system prevents blow by (emissions produced by the engine combustion chambers which escape into the crankcase) from entering the atmosphere. By re-circulating the gases back into the intake system, blow by gases are burned along with the incoming air fuel mixture.
Evaporative Control System
The emissions created by the evaporation of raw fuel is controlled by the use of a closed ventilation system for the fuel tank, and a canister filled with activated charcoal to capture the fuel vapors. The charcoal canister captures and stores the vapors as they expand. When the engine is started, a valve is opened allowing the engine to draw air through the charcoal canister thereby also drawing in and burning the stored fuel vapors.
Engine Design: Improved Combustion System (IMCO)
Starting in the 1960's a group of engine modifications were designed to improve combustion and reduce HC and CO in the exhaust. It included a heated primary air system, carburetor design changes, fuel injection, engine "breathing" refinements and spark timing controls.
