Caterpillar Inc.
Early pilot lean burn strategy in dual fuel engine using targeted pilot flames

Abstract:

Operating a dual fuel engine system includes injecting an early shot and a second shot of a liquid fuel into a cylinder after a late closing timing of an intake valve, and producing a first and a second pilot flame based on ignition of the early shot and the second shot of liquid fuel. The early shot of liquid fuel is targeted such that a distribution of ignition points of the first pilot flame is biased outwardly of a combustion bowl in the piston. Propagation of the first and second pilot flames from geometrically distinct ignition locations rapidly increases pressure and temperature in the cylinder to provide fast combustion of a lean mixture of a gaseous fuel and air in a main charge in the cylinder.