Patent ID: 7278259

Claim:
A method for retrofitting a diesel engine, the diesel engine drawing intake air through an air intake structure including an air filter for filtering the intake air, the method comprising: (a) installing a blow-by filter for filtering blow-by gas generated by the diesel engine to reduce blow-by gas emissions, the blow-by filter being installed in gas-flow communication with a blow-by vent structure of the diesel engine and in further gas-flow communication with the engine air intake structure; and (b) installing an exhaust treatment device for treating exhaust gas generated by the diesel engine to reduce exhaust gas emissions, the exhaust treatment device being installed in gas-flow communication with an engine exhaust port structure of the diesel engine, the exhaust treatment device including a substrate for reducing the exhaust gas emissions, the substrate being catalyzed with a diesel oxidation catalyst to promote the oxidation of hydrocarbons, wherein the blow-by filter and the exhaust treatment device are configured to provide at least a 25 percent reduction in total engine particulate matter emissions when the blow-by filter and the exhaust treatment device are used to retrofit a model year 1991-2003 on-highway diesel engine rated to produce from 150-600 horsepower.