Jet Air Suction Port (JASP) Improves Fuel Consumption of 4-Stroke Cycle Gasoline Engines at Idle

On 4-stroke cycle engines, the authors reported that under certain conditions the cylinder pressure, measured during the suction stroke with a low-pressure pickup, dropped below the critical pressure. Noting this considerable negative cylinder pressure during the suction stroke, the authors devised a Jet Air Suction Port (JASP), which was opened and closed by piston movement near bottom dead center.

As a result, it was possible not only to burn lean mixtures steadily, but also to decrease the fuel consumption 10 to 30 % at idle by the jet air flow generated automatically from the JASP. Reductions in THC, CO and NO at idle were also noted.