Unfortunately, just adding extra fuel to an engine doesnt make more power,a greater amount of air must also be added to supply the additional oxygen needed for proper combustion.Fuel is only added by the engine management system according to the corresponding fix ratio to air as set by the manufacturer or by resetting the engine management system when it detects the air through the sensors.
Problem
A naturally aspirated combustion engine is volumetrically efficient so that it can pack in more air into the combustion chamber than what is normally supplied by the intake system.However,it also needs and consumes more air at speeds than what can be delivered with the stock intake system.It is therefore said to have the capability but not so much the ability.Therefore , you can basically require an air pump which forces more air/fuel mixture into the engine giving you more power with the same engine capacity.Therefore , to make more power,we need to add more fuel,and to achieve this,we need to force more air into the engine.A forced Induction system accomplishes this. Volumetric efficiency compares the amount of air that flows into the cylinder with the cylinder swept volume as the cylinder breathes on the intake stroke.ie the ratio of the volume of fresh charge taken in during the suction stroke to the full piston displacement.
Volumetric efficiency depends not only on the engine displacement value and current engine speed but also on other factors such as how efficient the ports flow is and the length of the intake stroke.To put it simply, an engine will consume large volumes of air each minute depending on its displacement.
For example, at 6000rpm a normal 1.6 engine requires 120 CFM,2000 cc requires 190 CFM,and 5000cc requires 470 CFM of air. The forced induction system must ideally supply more air than what its engine requires at wide open throttle.
Solution : Forced Induction
Forced Induction is simply the process of using a mechanical system to pressurize the air available to your engine intake system.There are several methods which may either include a supercharger; which is belt driven from the crank to work an air compressor.The other more popular method is for the supercharger that uses exhaust gas from the outlet exhaust manifold to drive a turbine.A less popular system utilizes an electric boost system that positions an enclosed electric boosts system that positions an enclosed electric fan module in line with the air intake pipe.Lastly,a passive blower (static swirling device) without an electric motor placed in line with the air intake pipe to work the blower.The air induction from the air intake will cause the blower to swirl thus creating air pressure when placed at the right direction. The greater the induction pressure,the greater the blower swirls, creating even greater pressures. Many enthusiasts claim to have experience actual HP gained using the passive version claiming better atomization of fuel and air. The other design variation is made popular by Cyclone that utilizes static fins fashion in such a way to channel air flow in order to create pressure.
Electric Fan Boost
Electric fan boost uses a high powered electric motor drawing energy from the car battery to drive a small mechanical fan (normally an axial - flow fan unit) to slightly pressurize the intake air.The fan can either be operated at full throttle or by a switch on demand like Nitrous.At full throttle they use a micro switch link to the throttle foot paddle or to the throttle by wire link at the engine bay.This is a mild form of forced induction that helps push more air into the engine : some call it a light turbo effect.
Manufactures like e-Ram, VPM, ADM, electric supercharger and many other systems are designed to operate only at full throttle since this is when you want the most air pressure available to your engine.Products such as the ADM Air charger have a variable speed system and a separate electronic controller to monitor the engine load through the vacuum system and vary the fan speed to match the engine load.The electric fan boost works as a standalone and does not to be linked to the Electronic Fuel Injection (EFI) system.
The "light turbo effect" is said to provide 5 to 15 hp of power and 10-18 % of torque on a number of engines.Moreover, because it is electrically powered , there are no associated parasitic power losses.The ADM is said to take up about 15 amps of current and will flow more than 500 CFM of air even at 2,000rpm when it detects a high engine load.The e-RAM uses a 791 watt axial flow fan drawing 57 amps from the batteries that produces 1 to 1.7 psi depending whether you use one or two of their fan units.
The e-RAM claims to flow at 1000 CFM of air and promises 4-6% horsepower increases through out the 3000 to 6000 RPM range.Electric fan boost basically produces a much lower level boost when compare to a supercharger or turbo but spool up faster than the other two systems due to its lightweight.However,the open axial-flow fans is very efficient in moving tots of air flow at small pressures,where traditional turbo/superchargers are very good at making pressure,but need extreme speeds to match flow rates of most engines.
Electric boost systems are unlike the full blown turbo or supercharging systems which employs a centrifugal impeller that must run all the time to produce matched engine airflow,with high pressure air compression (4 to 15 psi is normal) . Generating pressure at air flow rates takes a large amount of power. That is why roots , screw and centrifugal compressors require between 15-20 hp taken directly from the engine in order to generate just 5 psi to 6 psi on a small engine.Larger engines require even more HP to drive the compressor in order to generate this level of boost at the higher air flow rates these engines require. The engine belts (or exhaust for turbos) must drive the compressor at a high enough rate of speed to generate enough air flow so as to continually provide more air than the engine is trying to take in.Coupling the rotation of the compressor directly with the rotation of the engine allows the compressor to continue to generate pressure,even when the engines requirement for air increases. Also,each 1 psi that is added to the intake at these flow rates drastically increases the amount of power required to perform this task.For example,the airflow needed for a 2.5 liter engine at 6000 rpm is 265 CFM.At only 6 PSI you would need 10 to 15 HP to create this type of pressure.
The idea of using an electrically driven fan for boost is a good concept except that it restricts air flow because it needs to be situated in line with the intake system.The fan should be ideally constantly running
at speeds and also generate pressure in order not to create restriction when it is stationary.
This means it will have to use a low powered electric motor that wont draw any significant electrical energy so it wont overheat if used in constant duty or use a bigger diameter fan from that of your intake tube ,otherwise it will just restrict air flow.Some manufacturers like the e Ram has 3.6 inches inside diameter to mitigate the restriction when not energize. One way to beat this,is to havea twin intake pipe that dedicates
one of its pipe for the fan if you have the space.
u understand all this Yaz??wakakakaka
ReplyDeleteno. but i think our manufacturers do.
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