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US 9,869,258 B2Granted
EGR for a two-stroke cycle engine without a supercharger
AssigneeAchates Power, Inc.
InventorEric P. Dion
Life of this patent
Estimating the term…
Abstract
A two-stroke cycle, turbo-driven, opposed-piston engine with one or more ported cylinders and uniflow scavenging has no supercharger. The engine includes a high pressure EGR loop and a pump in the EGR loop to boost the pressure of the recirculated exhaust products.
Claims3
A uniflow-scavenged, two-stroke cycle, opposed-piston engine comprising:
- at least one cylinder with piston-controlled exhaust and intake ports, the exhaust and intake ports being longitudinally spaced so as to be disposed near respective ends of the at least one cylinder;
- two crankshafts, in which each exhaust piston couples to a first crankshaft and each intake piston couples to a second crankshaft;
- an exhaust channel coupled to at least one exhaust port of the engine;
- a charge air channel coupled to at least one intake port of the engine;
- a power-assisted turbocharger with:
- a compressor output coupled to the charge air channel;
- a turbine coupled to the exhaust channel for being rotated by exhaust gas passing through the turbine;
- and
- a turbine output coupled to an exhaust pipe;
- a high pressure exhaust gas recirculation (EGR) loop having a loop input coupled to the exhaust channel upstream of the turbine and a loop output coupled to the charge aft channel downstream of the compressor and simultaneously connected to an inlet of at least one charge aft cooler;
- an electrically-driven pump in the high pressure EGR loop to pump exhaust gas through the high pressure EGR loop into the charge air channel;
- an electrically-controlled variable valve in the high pressure EGR loop between the loop input and the pump;
- and
- a control unit connected to provide control signals for the power-assisted turbocharger, the pump, and the valve,
- wherein the engine has no supercharger.
12 more elements
A method of operating the uniflow-scavenged, two-stroke cycle, opposed-piston engine, the opposed-piston engine including:
- at least one cylinder with piston-controlled exhaust and intake ports, the exhaust and intake ports being longitudinally spaced so as to be disposed near respective ends of the at least one cylinder;
- two crankshafts, in which each exhaust piston couples to a first crankshaft and each intake piston couples to a second crankshaft;
- an exhaust channel coupled to at least one exhaust port of the engine;
- a charge air channel coupled to at least one intake port of the engine;
- a power-assisted turbocharger with:
- a compressor output coupled to the charge air channel;
- a turbine coupled to the exhaust channel for being rotated by exhaust gas passing through the turbine;
- and
- a turbine output coupled to an exhaust pipe;
- a high pressure exhaust gas recirculation (EGR) loop having a loop input coupled to the exhaust channel upstream of the turbine and a loop output coupled to the charge air channel downstream of the compressor and simultaneously connected to an inlet of at least one charge air cooler;
- an electrically-driven pump in the high pressure EGR loop to pump exhaust gas through the high pressure EGR loop into the charge air channel;
- an electrically-controlled variable valve in the high pressure EGR loop between the loop input and the pump;
- a control unit connected to provide control signals for the power-assisted turbocharger, the pump, and the valve;
- in which the engine has no supercharger, the method comprising:
- pressurizing charge air via the compressor of the power-assisted turbocharger;
- cooling the charge air being pressurized in at least one cooler;
- delivering the charge air being pressurized and cooled to an intake port of each of the one or more cylinders;
- and
- pumping engine exhaust gas in the high pressure exhaust gas recirculation (EGR) loop to an inlet of the at least one air charge cooler by controlling the electrically-driven pump in the high pressure EGR loop to reduce Nox emissions.
16 more elements
Dependencies are inferred from the claim text.