A combustion chamber for an opposed-piston engine includes a squish zone defined between circumferential peripheral areas of opposing end surfaces of the pistons, a cavity defined by one or more bowls in the end surfaces, and at least one injection port that extends radially through the squish zone into the cavity. The cavity has a cross-sectional shape that imposes a tumbling motion on air flowing from the squish zone into the cavity.

An engine includes a combustion chamber including a cylinder wall defining a cylinder, a fuel injector disposed in a first opening in the cylinder wall and a piston head disposed in the cylinder. A piston bowl at least partially defined by a wall having a generally spiral shape is provided in a top of the piston head.

A combustion chamber for an opposed-piston engine has a rotationally skewed shape in a longitudinal section that is orthogonal to a chamber centerline, between diametrically-opposed openings of the combustion chamber through which fuel is injected. The rotationally skewed shape interacts with swirl to generate a tumble bulk charge air motion structure that increases turbulence.