2003 Honda S2000 Owner's Manual - Page 253

Emissions Controls Exhaust Emissions Controls The exhaust emissions controls include four systems: PGM-FI, Ignition Timing Control, Secondary Air Injection System, and Three Way Catalytic Converter. These four systems work together to control the engine's combustion and minimize the amount of HC, CO, and NOx that comes out the tailpipe. The exhaust emissions control systems are separate from the crankcase and evaporative emissions control systems. PGM-FI System Ignition Timing Control System This system constantly adjusts the ignition timing, reducing the amount of HC, CO and NOx produced. Secondary Air Injection System During engine warm-up, air is pumped into the exhaust to reduce emissions when the engine is cold. Three Way Catalytic Converter The PGM-FI System uses sequential multiport fuel injection. It has three subsystems: Air Intake, Engine Control, and Fuel Control. The Engine Control Module (ECM) uses various sensors to determine how much air is going into the engine. It then controls how much fuel to inject under all operating conditions. The three way catalytic converter is in the exhaust system. Through chemical reactions, it converts HC, CO, and NOx in the engine's exhaust to carbon dioxide (CO2), dinitrogen (N2), and water vapor. Replacement Parts The emissions control systems are designed and certified to work together in reducing emissions to levels that comply with the Clean Air Act. To make sure the emissions remain low, you should use only new Genuine Honda replacement parts or their equivalent for repairs. Using lower quality parts may increase the emissions from your car. The emissions control systems are covered by warranties separate from the rest of your car. Read your warranty manual for more information. Onboard Refueling Vapor Recovery The Onboard Refueling Vapor Recovery (ORVR) system captures the fuel vapors during refueling. The vapors are adsorbed in a canister filled with activated carbon. While driving, the fuel vapors are drawn into the engine and burned off. Technical Information 257