Unsteady Three-Dimensional Computational Experiments of the Single-Point Auto-Ignition Engine Based on Semispherical Supermulti-Jets Colliding with Pulse for Automobiles

Supercomputer simulations substantiate a high potential of the new compressive combustion principle based on supermulti-jets colliding with pulse, which was previously proposed by us and can maintain high compression ratio for various air-fuel ratios. An original governing equation extended from the stochastic Navier-Stokes equation lying between the Boltzmann and Langevin equations is proposed and the numerical methodology based on the multi-level formulation proposed previously by us is included. For capturing instability phenomena, this approach is better than direct numerical simulation (DNS) and large eddy simulation (LES). A simple two-step chemical reaction model modified for gasoline is used. A small engine having a semispherical distribution of seventeen jets pulsed is examined here. Pulse can be generated by a rotary plate valve, while a piston of a short stroke of about 65mm is also included. Computations from 2,000 rpm to 20,000rpm at some loads for the present engine having supermulti-jets colliding with pulse and conventional super- or turbo-charged system are done, which show a high thermal efficiency over 60%, because there is very less heat loss on combustion chamber and piston surface. Emphasis is also placed on the fact that, in this new engine (Fugine), higher compression results in less combustion noise.