Spark ignition engine exhaust system
AssigneeFord Motor Company
InventorsVemulapalli D. N. Rao, Harry A. Cikanek
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Abstract
An exhaust system for a spark ignition engine on an automotive vehicle including an exhaust filter disposed downstream of a spark ignition engine for condensing hydrocarbons in exhaust gases from the engine during a first time period after start of the engine, a bypass structure for bypassing at least a portion of exhaust gases around the exhaust-filter to heat the exhaust filter during a second time period after the first time period and evaporate the condensed hydrocarbons, and a catalytic converter disposed downstream of the exhaust filter to oxidize the evaporated hydrocarbons and reduce NO.sub.x in exhaust gases passing therethrough. A method is also provided.
Claims20
An exhaust system for a spark ignition engine on an automotive vehicle comprising:
- filter means disposed downstream of a spark ignition engine for condensing hydrocarbons in exhaust gases from the engine during a first time period after start of the engine;
- bypass means for bypassing at least a portion of exhaust gases around said filter means to heat said filter means during a second time period after said first time period and evaporate the condensed hydrocarbons;
- and
- a catalytic converter disposed downstream of said filter means to oxidize the evaporated hydrocarbons and reduce NO.sub.x in exhaust gases passing therethrough.
A method of reducing hydrocarbons and NO.sub.x in an exhaust system for a spark ignition engine on an automotive vehicle, said method comprising the steps of:
- providing a filter downstream of a spark ignition engine and a catalytic converter downstream of the filter for an exhaust system;
- condensing hydrocarbons in exhaust gases from the engine on the filter during a first time period after start of the engine;
- bypassing at least a portion of exhaust gases around the filter to heat the filter during a second time period after the first time period and evaporate the condensed hydrocarbons;
- and
- oxidizing the evaporated hydrocarbons and reducing NO.sub.x in exhaust gases passing through the catalytic converter.
Dependencies are inferred from the claim text.