Top: Prototype engine for automobiles; Below: Prototype engine for aircraftProf. Ken Naitoh of Waseda Univ.'s Faculty of Science and Engineering and his associates have discovered a new compressive combustion principle able to yield stand-alone engines with double or higher the thermal efficiency potential of conventional engines, independent of their size. If engines utilizing this principle can be put to use in practical applications, the researchers say they could help solve today's immediate environmental energy problems.

This new compressive combustion principle was formulated by Naitoh through the development of a new thermofluid dynamics theory, as well as thought experiments, supercomputer simulations and high-speed airflow experiments drawing on that theory. The fundamental principle is that thermal efficiency can be raised by reaching a higher compression ratio. This is achieved through pulsed collisions of multiple high-speed jets of an air-fuel gas mixture at microscopic regions in the central area of a combustion chamber. The approach has been improved to allow its use in practical applications with the addition of three new technologies.

According to Naitoh, the method is expected to be lower in cost than use of batteries in electrical vehicles, and could also reduce noise and eliminate the need for cooling mechanisms in internal combustion engines.

If the effectiveness of this principle can be confirmed through combustion tests, says Naitoh it will not only open up the doors to new lightweight, high-performance aerospace vehicles, it would also lead to prospects of next-generation, high-performance engines for automobiles. The maximum thermal efficiency of present-day gasoline engines for automobiles is on the order of 30%, and is believed to fall to a level as low as 15% in states from idling to low-speed city driving. At the 60% efficiency projected by Naitoh with his new combustion principle, a fuel consumption superior to that of current hybrid system automobiles could be possible.

These research results were announced in research papers at events including the spring congress of the Society of Automotive Engineers of Japan (JSAE), held in May 2013, and the conference of the American Institute of Aeronautics and Astronautics (AIAA), held in San Diego in June 2013, as well as in journals and magazines on science and technology.

Ken Naitoh Laboratory

Source: ACN Newswire