Trapped burned gas fraction control for opposed-piston engines with uniflow scavenging

摘要

A trapped burned gas fraction is controlled in a two-stroke cycle opposed-piston engine with uniflow scavenging by adjusting an external EGR setpoint in real time. The adjusted setpoint is used to control EGR flow in the engine's air handling system.

主权项

1. A uniflow-scavenged opposed-piston engine equipped with an air handling system, comprising:
at least one cylinder with a bore, longitudinally-spaced exhaust and intake ports, and a pair of pistons disposed in opposition in the bore and operative to open and close the exhaust and intake ports during operation of the engine; a charge air channel to provide charge air to at least one intake port; an exhaust channel to receive exhaust gas from at least one exhaust port; an exhaust gas recirculation (EGR) loop having a loop input coupled to the exhaust channel and a loop output coupled to the charge air channel; and, a control mechanization operable to:
determine a value of a trapped air handling parameter based on elements of combustion trapped in the cylinder by the last port of the cylinder to close during a cycle of engine operation and adjust the value of the trapped air handling parameter in response to a rate of EGR flow in the EGR loop; andadjust the rate of EGR flow in the EGR loop based on the adjusted value of the trapped air handling parameter.