The Kadenacy effect is an effect of pressure-waves in gases. It is named after Michel Kadenacy who obtained a
French patent
A patent is a type of intellectual property that gives its owner the legal right to exclude others from making, using, or selling an invention for a limited period of time in exchange for publishing an enabling disclosure of the invention."A p ...
for an engine utilizing the effect in 1933. There are also European and US patents. In simple terms, the momentum of the
exhaust gas
Exhaust gas or flue gas is emitted as a result of the combustion of fuels such as natural gas, gasoline (petrol), diesel fuel, fuel oil, biodiesel blends, or coal. According to the type of engine, it is discharged into the atmosphere through an ...
leaving the cylinder of an
internal combustion engine
An internal combustion engine (ICE or IC engine) is a heat engine in which the combustion of a fuel occurs with an oxidizer (usually air) in a combustion chamber that is an integral part of the working fluid flow circuit. In an internal combus ...
creates a pressure-drop in the
cylinder
A cylinder (from ) has traditionally been a three-dimensional solid, one of the most basic of curvilinear geometric shapes. In elementary geometry, it is considered a prism with a circle as its base.
A cylinder may also be defined as an infin ...
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
300px, Diagram of a pulsejet
A pulsejet engine (or pulse jet) is a type of jet engine in which combustion occurs in pulses. A pulsejet engine can be made with few or no moving parts, and is capable of running statically (i.e. it does not need ...
engines and in
two-stroke
A two-stroke (or two-stroke cycle) engine is a type of internal combustion engine that completes a Thermodynamic power cycle, power cycle with two strokes (up and down movements) of the piston during one power cycle, this power cycle being comple ...
piston engines and is important in the design of high-performance
motorcycle engine
A motorcycle engine is an engine that powers a motorcycle. Motorcycle engines are typically two-stroke or four-stroke internal combustion engines, but other engine types, such as Wankels and electric motors, have been used.
Although some moped ...
s.
Pulse jets
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
crankcase
In a piston engine, the crankcase is the housing that surrounds the crankshaft. In most modern engines, the crankcase is integrated into the engine block.
Two-stroke engines typically use a crankcase-compression design, resulting in the fuel/a ...
compression and, in large engines, by the use of a
Roots supercharger
The Roots-type blower is a
positive displacement lobe pump which operates by pumping a fluid with a pair of meshing lobes resembling a set of stretched gears. Fluid is trapped in pockets surrounding the lobes and carried from the intake si ...
or
turbocharger
In an internal combustion engine, a turbocharger (often called a turbo) is a forced induction device that is powered by the flow of exhaust gases. It uses this energy to compress the intake gas, forcing more air into the engine in order to pro ...
.
See also
*
Exhaust pulse pressure charging Exhaust pulse pressure charging (EPPC) 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 ...
*
Inertial supercharging effect The inertial supercharging effect is the increase of volumetric efficiency in the cylinder of an engine.
Background
The internal combustion engine is the most common engine found in mechanical devices across the world. The engine is powered by an ...
*
Pressure wave supercharger
A pressure wave supercharger (also known as a wave rotor) 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 wi ...
*
Supercharger
In an internal combustion engine, a supercharger compresses the intake gas, forcing more air into the engine in order to produce more power for a given displacement.
The current categorisation is that a supercharger is a form of forced induct ...
References
Pulse-jets website
External links
Reference to European patent
Engine technology
Two-stroke engine technology
Supercharging
Exhaust systems
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