A conventional piston engine has pistons with solid metal tops. In a valved-piston engine, the top of the piston has holes in it and valves are installed in the holes. The piston also contains a mechanism for opening and closing the valves.
As shown in the illustration above, a valved-piston engine would have two crankshafts. There would be two pistons inside each cylinder. One of these pistons is referred to as the intake piston, the other piston is referred to as the exhaust piston. One side of the engine is called the intake side, the other side is called the exhaust side. The illustration above shows the four strokes of the engine: the intake stroke, the compression stroke, the power stroke, and the exhaust stroke.
An offset-bore engine is an engine with cylinder bores that are out-of-line with each other. The pistons in an offset-bore engine may have solid heads or valved heads, like in a valved-piston engine.
Dual Connecting Rods.
The illustrations below show pistons with dual connecting rods. If dual connecting rods are used, the pistons can be made larger. If the engine is a valved-piston engine, a larger number of valves can be installed in each piston.
Improved Valved-Piston Engine With Single Crankshaft.
The valved-piston engines shownat the top of this page are designed with dual crankshafts. If it also possible to design a valved-piston engine that has only one crankshaft. The illustrations below show valved-piston engines with a single crankshaft.