Piston assembly with opposing injection regions for an opposed-piston engine

An opposed-piston engine, comprising:

• a cylinder block with a plurality of cylinders disposed in an inline array along a length of the cylinder block;
• a pair of pistons disposed in opposition in each cylinder;
• each piston of the pair of pistons comprising an inner ring belt region, an outer ring belt region, and a wristpin bore with a wristpin axis, the wristpin bore for receiving a wristpin coupling the piston to a connecting rod that swings in a connecting rod motion envelope that is substantially orthogonal to the wristpin axis, the piston further comprising a crown with an end surface and a bowl in the end surface configured to form a combustion chamber in cooperation with a bowl of an adjacent end surface of an opposing piston, the end surface including a pair of injection regions across which fuel is injected into the bowl;
• a respective injection trench situated in each injection region;
• wherein the injection regions are disposed in respective diametrically-opposed quadrants of the end surface, situated at locations that are offset arcuately between the wristpin bore axis and the envelope of motion;
• wherein each injection region extends along a respective arc concentric with the center of the circular peripheral edge;
• and,
• wherein the respective arc of each injection region subtends an angle of 50-70 degrees, with the vertex of the angle being coincident with a longitudinal axis of the piston.