Kadenacy effect
Encyclopedia
The Kadenacy effect is an effect of pressure-waves in gases. It is named after Michel Kadenacy who obtained a French
patent
for an engine utilizing the effect in 1933. There are also European and US patents. In simple terms, the momentum of the exhaust gas leaving the cylinder of an internal combustion engine
creates a pressure-drop in the cylinder
which assists the flow of a fresh charge of air, or fuel-air mixture, into the cylinder. The effect can be maximized by careful design of the inlet and exhaust passages.
s.
compression and, in large engines, by the use of a Roots blower.
France
The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...
patent
Patent
A patent is a form of intellectual property. It consists of a set of exclusive rights granted by a sovereign state to an inventor or their assignee for a limited period of time in exchange for the public disclosure of an invention....
for an engine utilizing the effect in 1933. There are also European and US patents. In simple terms, the momentum of the exhaust gas leaving the cylinder of an internal combustion engine
Internal combustion engine
The internal combustion engine is an engine in which the combustion of a fuel occurs with an oxidizer in a combustion chamber. In an internal combustion engine, the expansion of the high-temperature and high -pressure gases produced by combustion apply direct force to some component of the engine...
creates a pressure-drop in the cylinder
Cylinder (engine)
A cylinder is the central working part of a reciprocating engine or pump, the space in which a piston travels. Multiple cylinders are commonly arranged side by side in a bank, or engine block, which is typically cast from aluminum or cast iron before receiving precision machine work...
which assists the flow of a fresh charge of air, or fuel-air mixture, into the cylinder. The effect can be maximized by careful design of the inlet and exhaust passages.
Uses
The Kadenacy effect has been utilized in pulse jet engines and in two-stroke piston engines and is important in the design of high-performance motorcycle engineMotorcycle engine
A motorcycle engine is an engine that powers a motorcycle.Motorcycle engines may be two-stroke or four-stroke, reciprocating or Wankel, single-cylinder or multicylinder , or single-rotor or twin-rotor . The engine typically drives the rear wheel, but some small bikes such as the Velosolex have a...
s.
Two-stroke engines
In a two-stroke engine the pressure-drop resulting from the Kadenacy effect assists the flow of a fresh fuel-air mixture charge into the cylinder. However, the Kadenacy effect alone is not sufficient and must be boosted in some way. In small engines this is done by crankcaseCrankcase
In an internal combustion engine of the reciprocating type, the crankcase is the housing for the crankshaft. The enclosure forms the largest cavity in the engine and is located below the cylinder, which in a multicylinder engine are usually integrated into one or several cylinder blocks...
compression and, in large engines, by the use of a Roots blower.
See also
- Exhaust pulse pressure chargingExhaust pulse pressure chargingExhaust pulse pressure charging is a system for supercharging two-stroke diesel engines of the loop-scavenge type. Loop-scavenge engines cannot be pressure-charged in the same way as uniflow engines or four-stroke engines because the inlet and exhaust ports are open at the same time.-Overview:The...
- Inertial supercharging effectInertial supercharging effectInertial supercharging effect is the result of incoming fuel/air charge developing momentum greater than intake stroke would generate alone. It is achieved by a combination of head/port configuration, and cam profile/valve timing....
- Pressure wave superchargerPressure wave superchargerA pressure wave supercharger is a type of supercharger technology that harnesses the pressure waves produced by an internal combustion engine exhaust gas pulses to compress the intake air. Its automotive use is not widespread; the most widely used example is the Comprex, developed by Brown Boveri...
- SuperchargerSuperchargerA supercharger is an air compressor used for forced induction of an internal combustion engine.The greater mass flow-rate provides more oxygen to support combustion than would be available in a naturally aspirated engine, which allows more fuel to be burned and more work to be done per cycle,...