An opposed-piston engine includes a ported cylinder and a pair of pistons disposed to reciprocate in the bore of the cylinder. A combustion chamber is defined by opposing shaped piston end surfaces as the pistons approach respective top dead center (TDC) locations in the bore. At the end of scavenging, the shaped end surfaces of the pistons interact with swirl to produce turbulence in the charge air motion in the combustion chamber; the additional bulk motions include tumble. Fuel is injected into the turbulent charge air motion along a major axis, of the combustion chamber.