It is often said that if you breathe well then you live
longer. Coming from a sports background, I always came across such motivational
lines by my coach. He always told me to breathe well whenever I used to train
for my 100m and 200m event. I thought that he was just acting smart to behave
like an alpha coach but actually he was giving a lesson of science through his
teaching. I am writing this blog just after Teachers' day that why I thought of
mentioning one of the greatest teachers who gave me life changing lessons and
one of which is in fact relevant to the topic. I realised it later that deep
breathing actually sends in more oxygen to the body which ultimately gets
converted into energy. My coach was right. Automobile also works like a human
body.
Every automobile has an engine that also requires oxygen
which gets mixed with the fuel and later combusted to crank out power. It is
known to everyone that more air means more oxygen and more oxygen means more
power production. We cannot replace a nose for improved breathing in human body
but it could definitely be done in an automobile. A conventional automobile has
an air intake system which is a path provided for the air to travel, purify and
in the end enter into the cylinder for combustion process. Stock air intake
system is not performance focused but rather focused on mileage and sound (air
intake system also defines the sound of a vehicle). Stock intakes have small
air tubes with sharper bends that waste a lot of energy when the air strikes
the wall at the exit end. Aftermarket/custom/performance air intake system is
tailored to improve air flow into the cylinders to trigger up torque with
horsepower by improving combustion. If rich mixture(more fuel less air) is send
to the cylinders, you would find some unburnt fuel at the tail pipe end. A lean
mixture(more air less fuel) on the other hand is believed to be the best for
optimum power production with no fuel left unburnt. A perfect air fuel ratio or
stoichiometric air fuel ratio is obtained when exactly 14.7 gram of air is combusted
with 1 gram of fuel. This means that 14.7 gram of air is enough to burn 1 gram
of fuel without any wastage of horsepower.
OXYGEN=HORSEPOWER
There are different types of air intake system used across
the globe which are:-
RAM air intake, short air intake and cold air intake system.
I’ll be confining myself to RAM air intakes only.
RAM air?
Ram intake is a racing or competition technology in which air
is associated with a moving automobile. Here is when Ram air comes into the
picture which is a forced jet of air. It is basically a principle used up by a
moving automobile where air starts to flow with respect to that moving
automobile in opposite direction towards each other. Air follows law of inertia
according to physics where the air won’t stop easily if it is moving or won’t
start moving easily if it is at rest. The moving air with greater dynamic
pressure gets forced into the intake is called ram air and slows down due to
the increased cross-section area of the tube which ultimately increases static
pressure. Much greater cylinder air filling could be obtained by this as
earlier it was just the downward movement of the piston which pulled in the air
due to vacuum created by the piston and only up till the time it reached
BDC(bottom dead centre). But now, the ram air would keep pushing itself into
the cylinder due to its inertia. Remember that ram air is continuously entering
the air tube and the fresh air entering the tube would push the already air
present inside the tube and this way as soon as the throttle is opened, ram air
would catapult or force itself to enter the cylinders. This allows greater
volume of air inside the tube.
Early life
Ram air intakes were first installed in 1960s in cars if road
vehicles are considered. Brands like Ford Mustang, Chevrolet Camaro, and
Pontiac GTO etc used this system earlier but later in 1970s due to some issues,
it lost its existence in production market. Cars with Ram intakes had hoods
with air ducts which raised its height. Cars in 80s era evolved with improved
power and performance. This happened by opening up the boundaries of racing
world and bringing technologies to the production world. Ram intake was already
used in different racing formats and was a bit on the higher side of cost.
Technicians needed to replace the hood in order to install Ram intakes. Some
felt it made the car look ugly and also blocked the front vision through the
cabin and finally discontinued it. Of course, it was available as an
aftermarket part but no longer was installed as a stock part. It made its
comeback in 1990s where again big brands started featuring this part in their
production cars. First production bike to come with this system was 1990
Kawasaki Ninja ZX12R which was one of the fastest bikes of its time and the
performance actually attracted many customers round the globe. Other competing
brands followed the same trend later.
Present life
Now manufacturers care no longer about front, side or back vision area. For example, you may go and check the visibility level by sitting inside a Chevrolet Camaro which is a great car but the area of vision through front screen along with other windows is reduced to make it a more aerodynamic car. Air filter is the largest part of the system and mostly is mounted right behind the nose or car grill. Grill is nothing but a mesh which allows air to flow through it. Right behind the grill is the air scoop which leads to air box followed by the rest parts of the system. Developers have come up with new locations of air duct or snorkel. Some cars come with air duct integrated in the front fender. This is just to isolate the snorkel from the engine and allow cold air to enter the cylinders. Hyper cars with top level performance have headlights designed specially to complete dual task. Firstly, to illuminate the road i.e. to light up the light and secondly to scoop in air. The headlight has a duct in the epicentre area which allows air to flow into it which later enters the air box.
Ram air intake is used in nearly all performance m/cs right from sportsbike to airplane. In sportsbike, due to its geometry cannot go through heavy parts like turbo charger and supercharger as it would increase the overall weight and reduce its nimbility. Recall that turbochargers and superchargers are not just a part but a system containing tubes, turbo and inter-coolers. It is possible to fit these systems in a bike and there are some production bikes like Kawasaki Ninja H2 which comes with these and have broken records but at the same time they are no less than riding a tank. Ram air intake system fits best into the picture and has given an impressive increase in power output figures. The system could be installed in a fuel injected bike without hassle as fitting it with a carburetor bike is a sweating job and often gives trouble even after installing one. However, if the carburetor is redesigned to fit with the system then it could work perfectly but eventually increase the overall cost of installation. Nearly all modern bikes come with this system and you might have even observed it but could not figure out anything about it. Bike has fairing with large scoops or snorkels integrated in it. Some of them are shown below.
My personal experience about this cosmetic change was that I
used to think that the bike had ability to fire bullets or missiles through
those ducts or scoops due to their shapes. C’mon, I was just a kid then!!! These
scoops are big hollow openings and are mounted inside the fairing. The shape
and location is precisely decided to forcefully induce greater volume of ram
air i.e. on the front end near the headlights usually on either side. The
location also determines stability of the bike as air exerts a great amount of
force on the bike when it hits the tube inside the intakes. This would
otherwise make the bike unstable at high speed and could lift the front end to
pop wheelies at high speed making high speed runs very dangerous. This is why
intake location should be synchronised well with the aerodynamics of the bike
which makes location an important factor to be considered. It is a more common
feature in bikes due to reliability, less wear and tear due to less moving
parts and a cheaper solution to improve horsepower.
The main parts are:-
Air box – Air duct or snorkel rams scoops in air and later sends it to the air
box. Air box is simply a hollow box containing air filter.
Air filter - In air filter, air with impurities is made to flow through
several layers of oil and charcoal and absorb the particulates/other impurities
and later pass on fresh air to the air tube.
Air tube - It is a plastic or metal tube depending on the automobile and does the
job of providing a smooth and straight path to the clean flowing air. More
energy is lost when the air strikes sharp bends in the air tube. Either by
making the bends smooth or using straight tubes could help in reducing the
energy loss.
Heat shield – It is an aluminium sheet or powder coated sheet that is
made to cover air filter and reduce sucking of warm air from the engine. At
high speed, cold air is sucked inside and no warm air travels to the air filter
due to high velocity of the car. Heat shield comes into picture when the
vehicle is moving at slow speed with warm engine. Also there is an extra shield
which avoids splashed water or mud from getting inside the intakes in wet
conditions.
Throttle body – It is a main part of the intake that controls the volume
of air travelling into the cylinders. It has one or more fancy butterfly valves
which move on their axis to open and close the throttle body. It is directly
connected and controlled by the accelerator pedal in cars or accelerator
throttle in bikes.
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