Porsche Carrera 911 997 owners manual page 221

text version of content this owner's manual page from owners manual to the vehicle Porsche Carrera 911, year of production 2004 - 2011:

How Emission Control Works Oxygen sensor The catalytic converters will be damaged by: When an automobile engine is running, it uses en- The oxygen sensor, installed in the exhaust pipe – push or tow starting the vehicle ergy generated through the combustion of a mix-continuously senses the oxygen content of the – misfiring of the engine ture of air and fuel. Depending on whether a car is exhaust and signals the information to an electron-– turning off the ignition while the vehicle is mov- driven fast or slowly or whether the engine is cold ic control unit. The control unit corrects the air/ing or or hot, some of the fuel (hydrocarbons) may not fuel ratio, so the engine always receives an accu- be burned completely, but may be discharged into rately metered air/fuel mixture. – driving until the fuel tank is completely empty the engine crankcase or exhaust system. Additon- – by other unusual operating conditions. al hydrocarbons may enter the atmosphere Crankcase ventilation through evaporation of fuel from the fuel tank. f Do not continue to operate your vehicle under These hydrocarbons (HC), when released into the Through crankcase ventilation, undesirable emis-these conditions, since raw fuel might reach air, contribute to undesirable pollution. sions from the engine crankcase are not permit-the catalytic converters. This could result in In addition, carbon monoxide (CO) and oxides of ted to reach the outside atmosphere. These emis-overheating of the converters. Federal law pro- nitrogen (NOx) contribute to engine emissions. sions are recirculated from the crankcase to the hibits use of leaded fuel in this car. They, too, are formed during the combustion proc-air intake system. From here the emissions mix ess and discharged into the exhaust system. with the intake air and are later burned in the en- gine. To reduce these pollutants, your Porsche is equipped with a precisely calibrated fuel injection Catalytic converters system to assure a finely balanced air/fuel mixture under all operating conditions.The catalytic converters are efficient “clean-up” devices built into the exhaust system of the vehi- cle. The catalytic converters burn the undesirable pollutants in the exhaust gas before it is released into the atmosphere. The exclusive use of unleaded fuel is critical- ly important for the life of the catalytic con- verters. Therefore, only unleaded fuel must be used. Maintenance, Car Care 219

owners manual Porsche Carrera 911

owners manual Porsche Carrera 911 - year of production: 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 - Porsche Carrera 911 997 owners manual EN