Abstract: An exhaust treatment system is provided. The system may include a particulate trap configured to remove one or more types of particulate matter from an exhaust flow of an engine. The system may also include a catalyst configured to chemically alter at least one component of the exhaust flow. Further, the system may include an exhaust conduit configured to direct the exhaust flow from the engine to the particulate trap and the catalyst. In addition, the exhaust treatment system may include a heating system configured to maintain the temperature of the catalyst above a first predetermined temperature. The heating system may also be configured to periodically raise the temperature of the particulate trap above a higher, second predetermined temperature to thereby effectuate a regeneration of the particulate trap by oxidizing particulate matter accumulated in the particulate trap.

Abstract: A method for recirculating exhaust gas includes operating an intake valve to open an intake port of a combustion chamber, operating an exhaust valve to open an exhaust port of the combustion chamber, and directing exhaust gas from the exhaust port to an exhaust recirculation port of the combustion chamber. The method also includes operating an exhaust recirculation valve to open the exhaust recirculation port to allow the exhaust gas to enter the combustion chamber and determining at least one valve actuation condition for controlling actuation of each of the intake valve and the exhaust recirculation valve.

Abstract: A first aspect of the present disclosure includes a power source for use with selective catalytic reduction systems for exhaust-gas purification. The power source may comprise a first cylinder group with a first air-intake passage and a first exhaust passage, and a second cylinder group with a second air-intake passage and a second exhaust passage. The power source may further include a first forced-induction system in fluid communication with the first air-intake passage, and a second forced-induction system in fluid communication with the second air-intake passage. A catalyst may be disposed downstream of the fuel-supply device to convert at least a portion of the exhaust stream in the first exhaust passage into ammonia.

Abstract: A method of operating an internal combustion engine may include selectively operating the engine in a first mode of operation, wherein fuel may be injected into compressed fluid to create a substantially heterogeneous mixture of fuel and compressed fluid, and fuel may be ignited by the heat of the compressed fluid. The method may also include selectively operating the engine in a second mode of operation, wherein fuel is injected into gas to create a substantially homogeneous mixture of gas and fuel, the substantially homogeneous mixture is compressed, and fuel is ignited by the heat of the compressed gas. The method may further include determining whether to operate the engine in the first or second mode according to engine conditions.

Abstract: A power source is provided for use with selective catalytic reduction systems for exhaust-gas purification. The power source has a first cylinder group fluidly connected to a first air-intake passage and a first exhaust passage, wherein the first air-intake passage is configured to provide air at a first set of characteristics. The power source also has a second cylinder group fluidly connected to a second air-intake passage and a second exhaust passage, wherein the second air-intake passage is configured to provide air at a second set of characteristics different from the first set of characteristics. An ammonia-producing catalyst may be disposed within the first exhaust passage and configured to convert at least a portion of a fluid in the first exhaust passage into ammonia.