EGR Rate Control For Internal Combustion Engine With Dual Exhaust-Ported Cylinders

摘要

A method of using exhaust gas recirculation (EGR) in an internal combustion engine. At least two of the cylinders are “dual exhaust-ported cylinders” having two exhaust ports. For each of these cylinders, one of the exhaust ports is connected to the EGR loop and the other of the exhaust ports is connected to the main exhaust line. These cylinders are controlled such that one exhaust port is open and the other exhaust port is closed during each engine cycle, and are operated, on a cycle-by-cycle basis so that all of the exhaust produced by a cylinder may be delivered to the EGR loop at any cycle. The number of cylinders operating as EGR cylinders per engine cycle is in response to a desired EGR rate.

主权项

1. A method of using exhaust gas recirculation (EGR) in an internal combustion engine having a number of cylinders, at least two of the cylinders being “dual exhaust-ported cylinders” having two exhaust ports, the engine further having an EGR loop and a main exhaust line, comprising:
for at least two dual exhaust-ported cylinders, connecting, via exhaust valves, one of the exhaust ports to the EGR loop and the other of the exhaust ports to the main exhaust line; controlling the at least two dual exhaust-ported cylinders on a cycle-by-cycle basis, such that for any engine cycle, one exhaust valve may be opened and the other exhaust valve may be closed; determining, for a selected engine cycle, whether at least one of the dual exhaust-ported cylinders is to be operated as an EGR cylinder, such that all of the exhaust produced by that cylinder is delivered to the EGR loop; and repeating the operating step for successive engine cycles, such that the number of cylinders operated as an EGR cylinder may vary from cycle to cycle; wherein the number of cylinders operating as EGR cylinders per engine cycle and the frequency of operation of any cylinder as an EGR cylinder are in response to one or more desired EGR rates.