Naitoh, K., Hasegawa, K., Kubota, T., Hashimoto, T. et al., "Development Of Fugine Based on Supermulti-Jets Colliding with Pulse: Leading to Stable Plug-Less Start and Improvement of HCCI with Satisfactory Strength of Structure," SAE Technical Paper 2014-01-2639, 2014, doi:10.4271/2014-01-2639.
In our previous reports based on computational experiments and fluid dynamic theory, we proposed a new compressive combustion principle for an inexpensive, lightweight, and relatively quiet engine reactor that has the potential to achieve incredible thermal efficiency over 60% even for small combustion chambers having less than 100 cc. This level of efficiency can be achieved with colliding supermulti-jets that create complete air insulation to encase burned gas around the chamber center, thereby avoiding contact with the chamber walls, including the piston.We originally developed an actual prototype engine system for gasoline. The engine has a strongly-asymmetric double piston and the supermulti-jets colliding with pulse, although there are no poppet valves. The number of jets pulsed for intake and exhaust is eight, while both of bore and stroke are about 40mm. The present prototype engine can widely vary point-compression strength due to the supermulti-jets and mechanical homogeneous compression level, by changing the phase of two gears and size ratio of two gears between the double piston.Experimental data obtained by combustion tests with a traditional starter motor indicates a possibility of stable engine start for gasoline without any plugs in case of mechanical compression ratio less than 10:1.