Ram-air intake
 | This articleneeds additional citations forverification.(June 2018) |
Aram-air intakeis anyintakedesign which uses the dynamic airpressurecreated by vehicle motion, orram pressure,to increase the static air pressure inside of the intake manifold on an internal combustion engine, thus allowing a greater massflow through the engine and hence increasing engine power.[1]
Design features[edit]
The ram-air intake works by reducing the intake air velocity by increasing the cross-sectional area of the intake ducting. When gas velocity goes the pressure is increased. The increased pressure in the air box will ultimately have a positive effect on engine output as more oxygen will enter the cylinder during each engine cycle.
Ram-air systems are used on high-performance vehicles, most often onmotorcyclesand performance cars. The 1990Kawasaki Ninja ZX-11C1 model used a ram-air intake, the very first on any production motorcycle.[2][3]Ram-air was a feature on some cars in the sixties. It fell out of favor in the seventies, but recently made a comeback. While ram-air intakes may increase thevolumetric efficiencyof an engine, they can be difficult to combine with carburetors, which rely on aventuri-engineered pressure drop to draw fuel through the main jet. As the pressurised ram-air may kill this venturi effect, the carburetor needs to be designed to take this into account, or, alternatively, the engine may needfuel-injection.
At low speeds (subsonic speeds) increases in static pressure are however limited to a few percent.
Aircraft[edit]
Pitotsensors are used to measure ram pressure which, along with static pressure, is used to estimate theairspeedof an aircraft.
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TA-4SU Super Skyhawk,note the ram-air intake mounted on the portside air intake for cooling the jet engine. -
Mikoyan-Gurevich MiG-15 -
Diagram of piston engine with (from left to right):
See also[edit]
References[edit]
- ^Cabello, Cabello; Baz, Pablo (2015-06-13)."Sistema aerodinámico Ram-Air: funcionamiento"[Aerodynamic system ram-air: operating mode].Motociclismo(in Spanish).Retrieved2016-08-20.
- ^Burns, John (December 24, 2013)."30 Years of Ninjas: 1984 GPz900 Ninja to 1990 ZX-11!".Cycle World.RetrievedDecember 2,2016.
- ^"Ram Air: Test".Sport Rider. October 1999.RetrievedDecember 2,2016.