Disc brakes
Disc brakes are an order of magnitude better at stopping
vehicles than drum brakes, which is why you'll find disc
brakes on the front of almost every car and motorbike built
today. Sportier vehicles with higher speeds need better
brakes to slow them down, so you'll likely see disc brakes on
the rear of those too.
Disc brakes are again a two-part system. Instead of the
drum, you have a disc or rotor, and instead of the brake
shoes, you now have brake caliper assemblies. The caliper
assemblies contain one or more hydraulic pistons which
push against the back of the brake pads, clamping them
together around the spinning rotor. The harder they clamp
together, the more friction is generated, which means more
heat, which means more kinetic energy transfer, which slows
you down. You get the idea by now.
This blog is about Mechanical Engineering; its Fundamental Subjects and everything related to Mechanical Engineering.......................
Monday, 16 December 2013
Disc brakes
Sunday, 15 December 2013
Surface Condenser
Surface Condenser ##
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A surface condenser is a commonly used term for a water-
cooled shell and tube heat exchanger installed on the
exhaust steam from a steam turbine in thermal power
stations. These condensers are heat exchangers which
convert steam from its gaseous to its liquid state at a
pressure below atmospheric pressure. Where cooling water
is in short supply, an air-cooled condenser is often used. An
air-cooled condenser is significantly more expensive and
cannot achieve as low a steam turbine exhaust pressure as
a water-cooled surface condenser.
Liquid Rocket Engine
Liquid Rocket Engine ##
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A liquid-propellant rocket or a liquid rocket is a rocket
engine that uses propellants in liquid form. Liquids are
desirable because their reasonably high density allows the
volume of the propellant tanks to be relatively low, and it is
possible to use lightweight centrifugal turbopumps to pump
the propellant from the tanks into the combustion chamber,
which means that the propellants can be kept under low
pressure. This permits the use of low-mass propellant tanks,
resulting in a high mass ratio for the rocket.
An inert gas stored in a tank at a high pressure is
sometimes used instead of pumps in simpler small engines
to force the propellants into the combustion chamber. These
engines may have a lower mass ratio, but are usually more
reliable 186,187 and are therefore used widely in satellites
for orbit maintenance.
4 stroke IC engine
The internal combustion engine is an engine in which the
combustion of a fuel (normally a fossil 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
combustion engine (ICE) the expansion of the high-
temperature and high- pressure gases produced by
combustion apply direct force to some component of the
engine. The force is applied typically to pistons, turbine
blades, or a nozzle. This force moves the component over
a distance, transforming chemical energy into useful
mechanical energy . The first commercially successful
internal combustion engine was created by Étienne Lenoir .
[1]
The term internal combustion engine usually refers to an
engine in which combustion is intermittent, such as the
more familiar four-stroke and two-stroke piston engines,
along with variants, such as the six-stroke piston engine
and the Wankel rotary engine. A second class of internal
combustion engines use continuous combustion: gas
turbines , jet engines and most rocket engines, each of
which are internal combustion engines on the same
principle as previously described.[1]
The ICE is quite different from external combustion
engines, such as steam or Stirling engines , in which the
energy is delivered to a working fluid not consisting of,
mixed with, or contaminated by combustion products.
Working fluids can be air, hot water, pressurized water or
even liquid sodium, heated in some kind of boiler . ICEs are
usually powered by energy-dense fuels such as gasoline or
diesel, liquids derived from fossil fuels . While there are
many stationary applications, most ICEs are used in mobile
applications and are the dominant power supply for cars,
aircraft, and boats.
A four-stroke engine (also known as four-cycle ) is an
internal combustion engine in which the piston completes
four separate strokes which comprise a single
thermodynamic cycle. A stroke refers to the full travel of
the piston along the cylinder, in either direction. While
risqué slang among some automotive enthusiasts names
these respectively the "suck," "squeeze," "bang" and "blow"
strokes. [1] they are more commonly termed
1. INTAKE: this stroke of the piston begins at top dead
center. The piston descends from the top of the
cylinder to the bottom of the cylinder, increasing the
volume of the cylinder. A mixture of fuel and air is
forced by atmospheric (or greater) pressure into the
cylinder through the intake port.
2. COMPRESSION: with both intake and exhaust valves
closed, the piston returns to the top of the cylinder
compressing the air or fuel-air mixture into the
cylinder head.
3. POWER: this is the start of the second revolution of
the cycle. While the piston is close to Top Dead
Centre, the compressed air–fuel mixture in a
gasoline engine is ignited, by a spark plug in gasoline
engines, or which ignites due to the heat generated
by compression in a diesel engine. The resulting
pressure from the combustion of the compressed
fuel-air mixture forces the piston back down toward
bottom dead centre.
4. EXHAUST: during the exhaust stroke, the piston once
again returns to top dead centre while the exhaust
valve is open. This action expels the spent fuel-air
mixture through the exhaust valve(s).
Diesel Engine Technical details:
Diesel Engine Technical details:
The design of Diesel engine is mostly alike the one of the
petrol engine – both have pistons, cylinders, valves. But the
ignition system in Diesel engines is lack in principle. Instead
of the usual spark in Diesel engines the fuel-air mixture is
ignited by high temperature of the compressed air. Let’s
review the Diesel engine operating principle.
The Diesel engine operating scheme
1-th stroke. The piston is moving down till lower dead point
and the fresh air is blown from intake valve.
2-th stroke. The piston is moving up till upper dead point
and the air in the cylinder is compressed multiple times (14
up to 25) and its temperature raises up to 700-800 C.
3-th stroke. At the moment the pistol reaches the upper
dead point the fuel is injected into cylinder. Combustion act.
The fuel-air mixture is expands and the piston is going
down.
4-th stroke. The piston is going down, and gases are
exhausted throw the open exhaust valve.
The fuel in the cylinder ignites with rapid pressure jump that
makes the engine to work noisy and with vibration. To
preserve the operation safety on the required level the Diesel
engine is designed much more durable than the petrol
engine. More durability assumes more heavy-weighted.
The fuel supply system of Diesel engine also differs from the
petrol-powered engine. The first thing to say it is more
complicated. The fuel in the combustion chamber should be
injected under high pressure and it is very minor in volume.
The engine is controlled by the electronic unit, which
controls the fuel pump and the injector according to data get
from sensors. That kind of design makes the engine much
more expensive.
Multimode manual transmission (MMT )
Multimode manual transmission (MMT )
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Multimode Manual Transmission (MMT or M/M, also
Multimode Transmission) is a type of sequential manual
transmission offered by Toyota. It uses a traditional manual
gearbox with an electronically controlled clutch. Multimode
Manual Transmission is available in the Aygo, Yaris, Corolla,
Corolla Verso and Auris in Europe, and should not be
confused with Multimode Automatic Transmission, which is
offered in the North American market by Toyota.
The Multimode Manual Transmission has the following gears:
R, N, E, M+, M-.
•R: R is the reverse gear. It is similar to R in both traditional
manual and in full automatic cars.
•N: N is the neutral gear. It is similar to N in both traditional
manual and full automatic.
•E: E is the functional equivalent of D in a full automatic. As
the gearbox in a MMT car is a manual gearbox, instead of
one with a torque converter as in a traditional automatic,
gear changes are noticeable. The accelerator should be
eased off slightly when gear changes to produce a smooth
ride.
•M- : Downshifts a gear in sequential fashion, from M5 (M6
in 6-speed MMT cars) to M1.
•M+: Up-shifts a gear in sequential fas
IC Engine Cooling System By Air Cooling Method
IC Engine Cooling System By Air Cooling Method ##
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Heat engines generate mechanical power by extracting
energy from heat flows, much as a water wheel extracts
mechanical power from a flow of mass falling through a
distance. Engines are inefficient, so more heat energy enters
the engine than comes out as mechanical power; the
difference is waste heat which must be removed. Internal
combustion engines remove waste heat through cool intake
air, hot exhaust gases, and explicit engine cooling.Engines
with higher efficiency have more energy leave as mechanical
motion and less as waste heat. Some waste heat is
essential: it guides heat through the engine, much as a water
wheel works only if there is some exit velocity (energy) in
the waste water to carry it away and make room for more
water. Thus, all heat engines need cooling to operate.
Piston
A piston is a component of reciprocating engines ,
reciprocating pumps, gas compressors and pneumatic
cylinders, among other similar mechanisms. It is the
moving component that is contained by a cylinder and is
made gas-tight by piston rings. In an engine, its purpose is
to transfer force from expanding gas in the cylinder to the
crankshaft 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.
Piston engines
Main article: Reciprocating engine
Internal combustion engines
Internal combustion engine piston, sectioned to show the
gudgeon pin.
The piston of an internal combustion engine is acted upon
by the pressure of the expanding combustion gases in the
combustion chamber space at the top of the cylinder. This
force then acts downwards through the connecting rod and
onto the crankshaft . The connecting rod is attached to the
piston by a swivelling gudgeon pin (US: wrist pin). This pin
is mounted within the piston: unlike the steam engine,
there is no piston rod or crosshead (except big two stroke
engines).
The pin itself is of hardened steel and is fixed in the
piston, but free to move in the connecting rod. A few
designs use a 'fully floating' design that is loose in both
components. All pins must be prevented from moving
sideways and the ends of the pin digging into the cylinder
wall, usually by circlips .
Gas sealing is achieved by the use of piston rings. These
are a number of narrow iron rings, fitted loosely into
grooves in the piston, just below the crown. The rings are
split at a point in the rim, allowing them to press against
the cylinder with a light spring pressure. Two types of ring
are used: the upper rings have solid faces and provide gas
sealing; lower rings have narrow edges and a U-shaped
profile, to act as oil scrapers. There are many proprietary
and detail design features associated with piston rings.
Pistons are cast from aluminium alloys . For better
strength and fatigue life, some racing pistons may be
forged instead. Early pistons were of cast iron , but there
were obvious benefits for engine balancing if a lighter alloy
could be used. To produce pistons that could survive
engine combustion temperatures, it was necessary to
develop new alloys such as Y alloy and Hiduminium ,
specifically for use as pistons.
A few early gas engines [note 1] had double-acting
cylinders, but otherwise effectively all internal combustion
engine pistons are single-acting . During World War II, the
US submarine Pompano[note 2] was fitted with a prototype
of the infamously unreliable H.O.R. double-acting two-
stroke diesel engine. Although compact, for use in a
cramped submarine, this design of engine was not
repeated.
CRAWLER DOZER KOMASTU
## CRAWLER DOZER KOMASTU ##
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The Komatsu D575A is a 1,150 horsepower (860 kW) tractor
crawler available as a bulldozer/ripper, the D575A-3, or as a
dedicated bulldozer, the D575A-3 SD Super Dozer.Equipped
with a standard blade, both versions are capable of moving
90 cubic yards (69 m3) of material per pass although the
D575A-3 SD Super Dozer is capable of moving 125 cubic
yards (96 m3) of material per pass if equipped with an
optional blade.The D575A-3 can dig to a maximum depth of
6 feet 9 inches (2.06 m) using its single shank ripper.
An indexing head
An indexing head:-
also known as a dividing head or spiral head,is a specialized
tool that allows a workpiece to be circularly indexed; that is,
easily and precisely rotated to preset angles or circular
divisions.
Indexing heads are usually used on the tables of milling
machines, but may be used on many other machine tools
including drill presses, grinders, and boring machines.
Common jobs for a dividing head include machining the
flutes of a milling cutter, cutting the teeth of a gear, milling
curved slots, or drilling a bolt hole circle around the
circumference of a part.
Whitworth quick return mechanism
Whitworth quick return mechanism :
The Whitworth quick return mechanism converts rotary
motion into reciprocating motion, but unlike the crank and
slider, the forward reciprocating motion is at a different rate
than the backward stroke. At the bottom of the drive arm,
the peg only has to move through a few degrees to sweep
the arm from left to right, but it takes the remainder of the
revolution to bring the arm back. This mechanism is most
commonly seen as the drive for a shaping machine.
Gas Turbine
## Gas Turbine ##
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An internal-combustion engine consisting of an air
compressor, combustion chamber, and turbine wheel that is
turned by the expanding products of combustion. The four
major types of gas turbine engines are the turboprop,
turbojet, turbofan, and turboshaft. Gas turbine - turbine that
converts the chemical energy of a liquid fuel into mechanical
energy by internal combustion; gaseous products of the fuel
(which is burned in compressed air) are expanded through a
turbine.
Saturday, 14 December 2013
Radiators
Radiators:-
Radiators are heat exchangers used to transfer thermal
energy from one medium to another for the purpose of
cooling and heating. The majority of radiators are
constructed to function
in automobiles , buildings , and electronics . The radiator is
always a source of heat to its environment, although this
may be for either the purpose of heating this environment, or
for cooling the fluid or coolant supplied to it, as for engine
cooling . Despite the name, radiators generally transfer the
bulk of their heat via convection, not by thermal radiation.
DTSI Technology & DTS-Si
What is DTSI Technology & DTS-Si ?
In DTSi, in Technology stead of 1 we are using 2 spark plugs. Flame front
formed is able to consume more air-fuel mixture as
compared with 1 spark plug, thus more complete burning and
more efficiency.
in DTS-Si, with addition of 2nd spark plug, what they are
doing is relocating valves position. With proper designing of
inlet and outlet valves you can induce extra swirl for inoming
air fuel mixture. Due to turbulence, extra efforts are provided
for proper mixing of air and fuel. (We can not allow petrol to
go in liquid droplet form, it should be finely atomized). With
well atomized air fuel mixture, efficiency increases.
Thursday, 12 December 2013
DUKE ENGINE
DUKE ENGINE- low vibration engine
* The engine with lowest vibration level 0.01 - 0.1 %
* variable compression ratio is possible
* multifuel capable
* Compact small dimensions
* 80% thermal efficiency
Duke Engines are in an advanced stage of developing a
unique high-speed, valve-less 5 cylinder, 3 injector axial
internal combustion engine with zero first-order vibration,
significantly reduced size and weight, very high power
density and the ability to run on multiple fuels and bio-fuels.
The Duke engine is suited for many uses including marine,
military, automobile, light aircraft and range extender
applications.
meaning of APDV, ASFS, ATFT.
What is the meaning of APDV, ASFS, ATFT... which we
generally find in bike engines????
APDV :
The term APDV stands for "Advanced Pro Series Digital
Variable Ignition System". APDV means, the injection of the
spark plugs is controlled digitally, which offers better and
efficient combustion of fuel. Bikes which APDV engine are
Splendor Pro, Passion Pro and the Splendor NXG.
ASFS:
The term ASFS stands for "Advanced Swirl Flow Induction
System". The technology is similar to that of the Bajaj
Auto’s DTS-Si (Digital Twin Spark – Swirl Induction)
technology. Previously Super Splendor was marketed as the
Quantum Core but it was not a great success. So the
company marketed the bikes in the name ASFS.
ATFT:
ATFT stands for "Advanced Tumble Flow Induction
Technology”.
Centrifugal pump
Centrifugal pump:-
Centrifugal pumps are a sub-class of dynamic
axisymmetric work-absorbing turbomachinery.
Centrifugal pumps are used to transport fluids by the
conversion of rotational kinetic energy to the
hydrodynamic energy of the fluid flow. The rotational
energy typically comes from an engine or electric motor.
The fluid enters the pump impeller along or near to the
rotating axis and is accelerated by the impeller, flowing
radially outward into a diffuser or volute chamber
(casing), from where it exits.
Common uses include water, sewage, petroleum and
petrochemical pumping. The reverse function of the
centrifugal pump is a water turbine converting potential
energy of water pressure into mechanical rotational
energy.
Wednesday, 11 December 2013
CANTILEVER BEAM
CANTILEVER BEAM-
A cantilever is a beam anchored at only one end. The beam
carries the load to the support where it is resisted by
moment and shear stress.Cantilever construction allows for
overhanging structures without external bracing. Cantilevers
can also be constructed with trusses or slabs.
Cantilevers are widely found in construction, notably in
cantilever bridges and balconies. In cantilever bridges the
cantilevers are usually built as pairs, with each cantilever
used to support one end of a central section. The Forth
Bridge in Scotland is an example of a cantilever truss
bridge.
p-V Diagram for the Ideal Diesel cycle
p-V Diagram for the Ideal Diesel cycle. The cycle follows the
numbers 1-4 in clockwise direction. In the diesel cycle the
combustion occurs at almost constant pressure and the
exhaust occurs at constant volume. On this diagram the
work that is generated for each cycle corresponds to the
area within the loop.