Power Plugs: Templates
Department of mechanical
engineering g.I.e.t (polly&tech)
CONTENTS:• What is an Air Powered Engine ?
• History of air engine.
• Classification of Air Engine.
• Various important parts of the engine.
(compressor, PLC circuit, Pulsed Pressure Control Valve,
Cam & Follower)
• Detail working of engine with compare to Two stroke petrol
• Advantages & Limitations.
What is an Air Powered Engine ?
• An engine powered by Compressed air is known as
air powered engine.
• Compressed air cars are powered by motors driven
by compressed air, which is stored in a tank at high
pressure such as 30 Mpa (4500 psi or 310 bar).
Rather than driving engine pistons with an ignited
fuel-air mixture, compressed air cars use
the expansion of compressed air, in a similar
manner to the expansion of steam in a steam engine.
History of air engine.
• Compressed air has been used since the 19th
century to power mines, locomotives and trains in
cities was previously the basis of
naval torpedo propulsion.
• In 1903, the Liquid Air Company located in London
England manufactured a number of compressed-air
and liquefied-air cars. The major problem with
these cars and all compressed-air cars is the lack of
torque produced by the "engines" and the cost of
compressing the air.
Classification Of Air Engine:
• Air engine is classified according to Position and
Number of Cylinders.
(a)Single Cylinder. Engine
has one cylinder and piston
connected to the crankshaft.
Opposed Cylinder Engine.
• Two banks of cylinders opposite each other on a
single crankshaft (a V engine with a 180 V). These
are common on small aircraft and some automobiles
with an even number of cylinders from two to eight
or more. These engines are often called flat engines.
Process description and discussion:
• To convert a conventional IC(four stroke petrol)
engine into an Air Powered one, few components
are to be replaced. First of all
1.Replace the spark plug with a pulsed pressure
control valve which can create required pressure.
2. Replace fuel tank with air vessel, as engine requires
pressurized air as input.
3. Replace cam with a modified cam. This is to be
done, so that both the inlet and outlet valves open and
close at the same time.
Various important parts of the engine.
• The parts which are newly introduced to be used in
air engine are:
• PLC circuit.
• pulsed pressure control valve.
• air vessel(Compressed Air Tank made up of carbon
• modified cam.
• A digitally operating electronic apparatus which uses a
programmable memory for the internal storage of
instructions for implementing specific functions such as
logic, sequencing, timing, counting, and arithmetic to
control, through digital or analog input/output modules,
various types of machines or processes.
• In essence, the programmable logic controller consists of
computer hardware, which is programmed to simulate the
operation of the individual logic and sequence elements that
might be contained in a bank of relays, timers, counters,
and other hard-wired components.
Pulsed Pressure Control Valve.
• The pulse sensing valve is a valve offered to provide
emergency closure based upon a decompression
pulse in the hydraulic medium used in large
hydraulic piping systems.
• A fluid decompression pulse is generally initiated
during a severe loss of compression on a fluid
• This decompression pulse travels at the speed of
sound in the hydraulic fluid from the load interface
point to the supply source.
Air vessel(Compressed Air Tank).
• A pressure vessel is a closed container designed to
hold gases or liquids at a pressure substantially
different from the ambient pressure.
• The pressure differential is dangerous and fatal
accidents have occurred in the history of pressure
vessel development and operation.
• So in case of air engine the vessel is made up of
• Which has high tensile & compressive strength with
lighter in weight.
• Replacement cam with a modified cam. This is to be
done, so that both the inlet and outlet valves open
and close at the same time. Main advantage of doing
this is to achieve better scavenging system.
• Also this will result in conversion of 4 stroke engine
into 2 stroke air engine, which in turn gives us the
benefit of low mean effective pressure requirement
in addition to other operational benefits.
About Carbon Fiber Used for Air Tank
• Carbonfiber,alternatively graphite fiber, carbon graphite or CF, is a
material consisting of fibers about 5–10 μm in diameter and composed
mostly of carbon atoms. The carbon atoms are bonded together in
crystals that are more or less aligned parallel to the long axis of the
fiber. The crystal alignment gives the fiber high strength-to-volume
ratio. Several thousand carbon fibers are bundled together to form
a tow, which may be used by itself or woven into a fabric.
• The properties of carbon fibers, such as high stiffness, high tensile
strength, low weight, high chemical resistance, high temperature
tolerance and low thermal expansion, make them very popular in
aerospace, civil engineering, military, and motorsports, along with
other competition sports. However, they are relatively expensive when
compared to similar fibers, such as glass fiber or plastic fibers.
Other parts Air engine.
• Piston : piston is a component of reciprocating engines,
reciprocating pump, gas compressor and pneumatic cylinder,
among other similar mechanisms. It is the moving component
that is contained by a cylinder and is made gas-tight
by piston ring.
• In an engine, its purpose is to transfer force from expanding
gas in the cylinder to the crank shaft via a piston
rod and/or connecting rod. In a pump, the function is
reversed and force is transferred from the crankshaft to the
piston for the purpose of compressing or ejecting the fluid in
the cylinder. In some engines, the piston also acts as
a valve by covering and uncovering ports in the cylinder wall.
Connecting Rod & Cylinder:
• Connecting Rod:
In a reciprocating piston engime, the connecting
rod or conrod connects the piston to the crank or crank shaft .
Together with the crank, they form a simple mechanism that
converts reciprocating motion into rotating motion.
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 blocks, which is typically
cast from aluminum, or cast iron before receiving precision
Crank Shaft:• Crank Shaft: The crankshaft, sometimes abbreviated
to crank, is the part of an engine that
translates reciprocating linear piston motion into rotation.
To convert the reciprocating motion into rotation, the
crankshaft has "crank throws" or “crank pins", additional
bearing surfaces whose axis is offset from that of the crank,
to which the "big ends" of the connecting rod from each
Crank Case:• Crank case: 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 cylinders which in a multicylinder engine are
usually integrated into one or several cylinder
Working Details Of Air Engine with
comparing normal 4 stroke IC engine.
Initial torque is supplied from the DC exciter motor, and then the
engine operation starts.
Stage 1: When the piston is in the TDC, compressed air is injected
through the pulsed air firing valve, which pushes the piston to BDC.
• On comparing it with the working of normal SI 4 stroke engine:
“Stage 1” of the air engine comprises of the combined operation of
“Suction stage” and “Power stage” of the normal 4 stroke SI engine.
“Stage 2” of the air engine comprises of the combined operation of
the “Compression stage” and “Exhaust stage” of the normal 4 stroke
• Stage 2: Due to the motion of the engine and its
inertia, the piston moves back to TDC, pushing the
air out of the valves.
• The plunger of the pulsed firing valve is controlled
by a timing circuit which is specifically a PLC
programmed circuit. It supplies the electronic
signals by which the plunger moves so that it opens
and closes the pulsed firing valve.
Benefits of Using Air Engine:
• Technical benefits:
The temperature of the engine while working will be
slightly less than the ambient temperature. Smooth
working of the engine due to very less wear and tear of
the components. There is no possibility of knocking.
No need of cooling systems and spark plugs or
complex fuel injection systems.
No use of expensive fossil fuels as the free air is
compressed and taken to use. For this reason people
can easily shift to the new technology. Compressors use
electricity for generating compressed air which is
relatively much cheaper and widespread. Smooth
working will lead to less wear & tear, so lesser
maintenance cost. cheaper in cost and maintenance and
it doesn’t cause any kind of harm to the environment.
Thus it is surely a futuristic mode of transport.
Limitations of Air engine:
• When air expands in the engine it cools dramatically
and must be heated to ambient temperature.
• This also leads to the necessity of completely
dehydrating the compressed air. pressure using a
• Refueling the compressed air container using a home
or low-end conventional air compressor may take as
long as 4 hours, though specialized equipment at
service stations may fill the tanks in only 3 minutes
Limitations of Air engine:
• The overall efficiency of a vehicle using compressed
air energy storage, using the above refueling
figures, is around 5-7%.For comparison, well to
wheel efficiency of a conventional internalcombustion drivetrain is about 14%,
• Early tests have demonstrated the limited storage
capacity of the tanks; the only published test of a
vehicle running on compressed air alone was
limited to a range of 7.22 km.