Doxfords vertical, opposed-piston two-stroke diesel engined had a single-crankshaft with connecting rods for both the lower and upper pistons. They are completely different to the well-known Junkers layout opposed-piston design, although Junkers also produced a small automotive engine based on the same system as Doxford. The upper pistons are connected to the single crankshaft by connecting rods each side of the main cylinder.
The connecting rods had self-aligning bearings at the top, and were hinged at their midpoint, connecting to the trunk piston guide pressure plate to provide location. Pressure oil feeds for lubrication were provided to all bearings. Large guides were provided for the upper piston connection plate and bearing, making the engine quite high in relation to its length.
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