Patent ID: 8375701
Filing Date: 2013-02-19
Classification: F01N,Y02T

Abstract:
1. An engine method, comprising: storing exhaust hydrocarbons by routing engine exhaust through a hydrocarbon trap assembly in a first direction through a first hydrocarbon trap and then a second hydrocarbon trap; storing fuel tank vapors in both a purging canister and the first and second hydrocarbon traps by routing the fuel tank vapors in the first direction; and purging both the hydrocarbon traps and the canister to an engine intake with an adjustable mixture of exhaust gas and fresh air routed through the hydrocarbon traps opposite the first direction, wherein the first hydrocarbon trap has a larger porosity than the second hydrocarbon trap, and wherein the adjustable mixture has a composition that brings a temperature of the adjustable purging mixture entering the hydrocarbon traps below a threshold that is based on each of oxygen content of the exhaust gas, adsorbent used in the hydrocarbon traps and canister housing used in the hydrocarbon trap assembly.