Skewed combustion chamber for opposed-piston engines

A method for operating a two-stroke cycle, compression ignition, opposed-piston engine including at least one cylinder with a bore and a sidewall, piston-controlled exhaust and intake ports near respective ends of the cylinder, a pair of fuel injectors that are mounted in the sidewall, and a pair of pistons disposed in opposition in the bore, by:

• introducing swirling charge air into the cylinder between end surfaces of the pistons, in which the end surfaces have flat aspects without outwardly-extending ridges;
• moving the pistons toward each other in a compression stroke;
• and,
• forming a combustion chamber between the end surfaces of the pistons,
• the combustion chamber having a centerline and further comprising:
• a rotationally skewed shape in a first longitudinal section of the combustion chamber that is symmetrical with respect to the combustion chamber centerline;
• and,
• an elongated shape in a second longitudinal section of the combustion chamber that is orthogonal to the first longitudinal section with opposite end portions that taper along the combustion chamber centerline toward the fuel injectors;
• and,
• the method further comprising the fuel injectors injecting opposing fuel sprays into swirling charge air in the combustion chamber.