It is always a challenge for the engine designers to increase power output while improving efficiency. Namikoshi Electronics of Japan has designed an unorthodox 4-in-1 concept engine as an alternative powerplant to automobile industry.
Initially it was designed as an electrical generator; however, the company realized that the engine could possibly change to suit the automotive industry. Instead of the conventional engine layout, the new 4-in-1 engine layout will consist of a big central unit surrounded by ball bearings, a central rod and a planetary gear.
This design has significant advantages over traditional engines in terms of friction and vibration. Compared to the conventional design which use lubricated friction bearings in crankshaft, connecting rod and piston pins, the new design mounts opposing pistons onto a reciprocating hub which uses ball bearings. In this way, the friction will be reduced. On top of that, the conventional design put the pistons connected in-line to the crankshaft whereas Namikoshi puts the opposing pistons onto one central unit which enables the engine to move back and forth in parallel. This design is believed to reduce vibration and it produces vibration levels similar to a rotary engine.
The Namikoshi concept engine weighs around 90 kg (198 lb), 1,500 cc and measured 800 mm (31.5 in) x 500 mm (19.7 in) x 250 mm (9.8 lb). The diameter is measured at 62 mm (2.4 in) and the stroke of each piston is set at 125 mm (4.9 in).