1999 Honda Civic Owner's Manual - Page 254

Emissions Controls Exhaust Emissions Controls The exhaust emissions controls include three systems: PGM-FI, Ignition Timing Control and Three Way Catalytic Converter. These three 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 under all operating conditions. Ignition Timing Control System This system constantly adjusts the ignition timing, reducing the amount of HC, CO and NOx produced. Exhaust Gas Recirculation (EGR) System 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)/ Powertrain Control Module (PCM)/ Transmission Control Module (TCM-HX model only) uses various sensors to determine how much air is going into the engine. It then controls how much fuel to inject Only on HX model The Exhaust Gas Recirculation (EGR) system takes some of the exhaust gas and routes it back into the intake manifold. Adding exhaust gas to the air/fuel mixture reduces the amount of NOx produced when the fuel is burned. Three Way Catalytic Converter 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 Acura 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. 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 (CO 2 ), dinitrogen (N 2 ), and water vapor. Technical Information