Opposed-piston engine structure with a split cylinder block

An engine structure for an opposed-piston engine, comprising:

• a cylinder block having opposing sides extending in an elongate dimension, L, of the cylinder block;
• the cylinder block including a plurality of cylinders, each cylinder including longitudinally separated intake and exhaust ends and an intermediate portion between the intake and exhaust ends;
• the plurality of cylinders being arranged an inline array along the elongate dimension, L, of the cylinder block, between the opposing sides of the cylinder block, such that the intake and exhaust ends of the cylinders are aligned in respective first and second sides of the inline array;
• a first crankcase assembly aligned with the elongate dimension and disposed along the first side of the inline array;
• a second crankcase assembly aligned with the elongate dimension and disposed along the second side of the inline array;
• and,
• the cylinder block including a plurality of bearing webs interdigitated with the cylinders;
• in which each cylinder comprises a cylinder tunnel formed in the cylinder block and a cylinder liner retained in the cylinder tunnel and all of the cylinders have a first diameter in the intermediate portions, a second diameter in the intake and exhaust ends, and the first diameter is larger than the second diameter;
• and,
• in which the cylinder block is split into two block sections at a seam defined on a plane that is orthogonal to the axes of all of the cylinders and passes through the intermediate portions of the cylinders.