Internal combustion engines are useful in various applications, including propulsion, electricity generation, and operation of heavy machinery. Internal combustion engines include one or more pistons that each reciprocate within a piston cylinder. The motion of the piston is driven by at least one combustion event in a combustion cycle. Internal combustion engines may be designed to run on gasoline fuel, in which a spark plug initiates combustion, on diesel fuel, that is compression ignited, or on other fuels, such as gaseous fuels. Engines can also run by combusting two different fuel types in a single combustion cycle.
The use of two fuels in a single combustion cycle can provide benefits by substituting a portion of fuel that may produce greater emissions, or that may have higher cost, with another fuel that may produce fewer emissions and/or have a reduced cost. However, the substitution of a large amount of fuel can lead to incomplete combustion or hot spots in the combustion chamber, which can result in decreased engine performance, greater emissions, and increased wear, among other potential issues. Such dual-fuel systems may be assisted by piston designs that address the unique aspects of combusting two fuels in a single combustion cycle.
An exemplary piston design is disclosed in U.S. Pat. No. 8,459,229 (“the '229 patent”) to Rothbauer et al. The '229 patent discloses a piston having a piston bowl including “surface features.” The surface features are located at the outer edge of the piston bowl and form a target for fuel spray from an injector. The surface features are intended to reduce soot and improve fuel-air mixing. While the piston surface features described in the '229 patent may be useful in some circumstances, they may be less helpful in other situations. For example, the position and shape of the surface features of the '229 patent may not be configured for dual-fuel combustion.
The disclosed method and combustion system for an internal combustion engine may solve one or more of the problems set forth above and/or other problems in the art. The scope of the current disclosure, however, is defined by the attached claims, and not by the ability to solve any specific problem.