An apparatus and method for improving efficiency of combustion engines. At least two combustion chambers are provided by contouring the surface of a piston or a cylinder head or a combination thereof. Such a contoured piston or cylinder head controls the peak temperature and pressure in order to combust the mixture efficiently, to increase power generated, and to decrease the amount of unused mixture exhausted from the combustion chamber. With the ability to control the peak pressure, the ignition plug can be fired at advanced ignition timing, thereby extending its life. The chambers are also designed to control flame propagation speed to reduce knock. Additionally, the chambers can also decrease the amount of pollutants such as NO.sub.x produced during combustion.
Charles Edward Roberts Jr.