| 摘要 |
A four-stroke reciprocating internal combustion engine that uses stratified exhaust gas recirculation to improve combustion is disclosed. The engine includes at least one combustion chamber defined by a cylinder, a reciprocating piston contained within the cylinder, and a cylinder head. Each combustion chamber is in fluid communication with at least one intake port and at least one exhaust port. At least one intake port includes an associated intake valve and an intake flow motion generating device for creating an intake fluid flow near the intake port. At least one exhaust port includes an exhaust valve that opens during the intake stroke at part load, and an exhaust flow motion generating device for creating an exhaust fluid flow near the exhaust port during the intake stroke at part load. An engine controller processes signals from at least one sensor and outputs a control signal to a variable valve lift and timing system for operating each intake valve and each exhaust valve such that an exhaust residual flow is inducted through at least one exhaust port into the combustion chamber and air or an air/fuel mixture is simultaneously inducted through at least one intake port into the combustion chamber. If air is inducted into chamber, fuel is injected into the air in the chamber. The engine produces a stratified exhaust gas and air-fuel mixture that includes: (i) recirculated exhaust gas which rotates in a first portion of the combustion chamber adjacent the exhaust port and which rotates about an exhaust vortex axis that extends substantially in the direction of reciprocation of the piston within the combustion chamber; and (ii) an air-fuel mixture which rotates in a remaining portion of the combustion chamber adjacent the intake port and which rotates about an intake fluid vortex axis extending substantially in the direction of reciprocation of the piston within the combustion chamber. Because of the stoichiometric operation of the engine, conventional three-way catalysts can be used for emission control. |
