Naturally aspirated engine: An engine using only the atmospheric pressure and vacuum in the intake manifold to fill the cylinder. Supercharged and turbo-charged engines are not naturally aspirated. Related posts: Personnel Management Operative Functions Administrative Role of PM Competency HR Management Role Change Personnel Policies Personnel Procedures Appealed Policies Implied Policies Specific Policies Personnel records Research Pure research Personnel research Attitude or Opinion Survey Turnover Secondary research Applied research Personnel audit Read more articles Previous PostMuffler Next PostNOx