Modular engine architecture

A reciprocating piston internal combustion engine comprising

• an extruded metal cylinder bore block defining a plurality of cylinder bores and corresponding cylinder coolant passages all extending completely through said block in the direction of extrusion, said cylinder bore block having flat, upper and lower surface portions adapted to be sealed to a cylinder head and a crankcase respectively, the diameter of each cylinder bore being adapted to accommodate a piston of specified diameter and the length of each said bore being adapted to accommodate a specified piston stroke;
• a crankcase for containing a crankshaft, a connecting rod from said crankshaft to each piston, and crankshaft bearing caps, said crankcase being adapted for location below said cylinder bore block in the operating position of said engine, said crankcase having side walls and a closed bottom for enclosing said crankshaft and an open top for assembly there-through of said crankshaft, connecting rods and bearing caps in said crankcase, the sides of said crankcase having top portions for sealing engagement with said cylinder bore block;
• and
• a mid-plate adapted for sealing engagement between said lower surface of said cylinder bore block and said top portions of said crankcase.

A method of making, on a single manufacturing line or in a single manufacturing cell, different members of a family of two or more multi-cylinder, reciprocating piston, internal combustion engines differing in specified piston displacement values, said method comprising

• selecting for each said engine an extruded metal cylinder bore block defining a plurality of cylinder bores all extending completely through said block in the direction of extrusion, said cylinder bore block having flat, upper and lower surface portions adapted to be sealed to a cylinder head and a crankcase respectively, the diameter of each cylinder bore being adapted to accommodate a piston of specified diameter and the length of each said bore being adapted to accommodate a specified piston stroke to produce the displacement value for the engine family member currently being made;
• using a cylinder head for the engine family member currently being made;
• using a common crankcase for each said member of said family of engines, said crankcase having a closed bottom with side and end walls shaped to contain a crankshaft, and piston connecting rods selected for the engine currently being made, said crankcase having an open top and said walls having flat, co-planar surfaces for sealing engagement with said cylinder bore block;
• selecting a mid-plate adapted for sealing engagement between said cylinder bore block and said surfaces of said crankcase, and
• assembling said cylinder head, said selected cylinder bore block, said mid-plate and said common crankcase in an engine structure in making members of said engine family.

A method of making, on a single manufacturing line or in a single manufacturing cell, different members of a family of two or more multi-cylinder, reciprocating piston, internal combustion engines differing in specified piston displacement values, said method comprising

• selecting for each said engine an extruded metal cylinder bore block defining a plurality of cylinder bores and corresponding coolant passage all extending completely through said block in the direction of extrusion, said cylinder bore block having flat, upper and lower surface portions adapted to be sealed to a cylinder head and a crankcase respectively, the diameter of each cylinder bore being adapted to accommodate a piston of specified diameter and the length of each said bore being adapted to accommodate a specified piston stroke to produce the specified displacement value for the engine family member currently being made;
• using a cylinder head for the engine family member currently being made;
• using a common cast crankcase for each said member of said family of engines, said crankcase having (1) a closed bottom with integral bearing supports for a crankshaft, (2) side and end walls shaped to contain said crankshaft, crankshaft bearing caps, and piston connecting rods selected for the engine currently being made, and (3) an open top, and said walls having flat, co-planar surfaces for sealing engagement with said cylinder bore block;
• selecting a mid-plate adapted for sealing engagement between said cylinder bore block and said surfaces of said crankcase, and
• assembling said crankshaft, bearing caps and connecting rods through the top of said common crankcase without inverting the crankcase and further assembling said cylinder head, said selected cylinder bore block, and said mid-plate with said crankcase in an engine structure in making members of said engine family.