Patent ID: 7818963

Claim:
A two-stroke system, comprising: a two-stroke natural gas fueled engine comprising at least one cylinder with an inlet port and an exhaust port; a silencer/catalytic converter unit comprising: a first volume configured to dampen spurious exhaust pressure excursions and to remove at least a portion of particulates contained in an untreated engine exhaust; and a second volume downstream from the first volume, wherein the second volume houses an oxidation catalyst configured to receive the untreated engine exhaust after dampening of the spurious exhaust pressure excursions and after removal of the portion of particulates, and the oxidation catalyst is configured to output a treated engine exhaust having lower emissions than the untreated engine exhaust; wherein the exhaust port is in fluid communication with the silencer/catalytic converter unit via an intake port in the first volume, and the first and second volumes are in fluid communication with each other; and an exhaust pipe configured to transport the untreated engine exhaust from the exhaust port of the two-stroke natural gas fueled engine to the intake port of the silencer/catalytic converter unit, wherein the exhaust pipe has a length tuned to maximize power output from the two-stroke natural gas fueled engine, wherein the length is dependent on a swept volume of a power cylinder, a crank angle at which an exhaust ports opens, and a rated speed for the two-stroke natural gas fueled engine.