elective 2 term paper...toti
TRANSCRIPT
-
8/7/2019 elective 2 term paper...toti
1/20
University of Southeastern PhilippinesObrero campus, Davao City
College of Engineering
In partial fulfillment of the requirements
in the subject of Elective 2
Submitted by:
Irwin Glenn O. JabagatBSME-5
Submitted to:
Dr. Roselio Lyndon Roble, PME, FPSME
-
8/7/2019 elective 2 term paper...toti
2/20
Diesel elements
Definition:
A diesel engine (also known as a compression ignition engine and sometimes capitalized
asDiesel engine) is an internal combustion engine that uses the heat of compression to
initiateignition to burn the fuel, which is injected into the combustion chamber during the final
stage of compression. This is in contrast to spark ignition engines such as a petrol engine (known
as agasoline engine in North America) or gas engine (using a gaseous fuel, not gasoline), which
uses a spark plug to ignite an air-fuel mixture. The diesel engine has the highest thermal
efficiency of any regular internal or external combustionengine due to its very high compression
ratio. Low-speed diesel engines (as used in ships and other applications where overall engine
weight is relatively unimportant) often have a thermal efficiency which exceeds 50 percent.
History:
The diesel engine is modelled on the Diesel cycleand the engine and thermodynamic cycle were
both developed by Rudolph Diesel in 1897. Rudolf Diesel, of German nationality, was born in
1858 in Paris where his parents were German immigrants. He was educated at Munich
Polytechnic. After graduation he was employed as a refrigerator engineer, but his true love lay in
engine design. Diesel designed many heat engines, including a solar-powered air engine. In 1892
he received patents in Germany, Switzerland, the United Kingdom and filed in the United States
for "METHOD OF AND APPARATUS FOR CONVERTING HEAT INTO WORK". In 1893
he published a paperdescribing a "slow-combustion engine" that first compressed air thereby
raising its temperature above the igniting-point of the fuel, then gradually introducing fuel while
letting the mixture expand "against resistance sufficiently to prevent an essential increase of
temperature and pressure", then cutting off fuel and "expanding without transfer of heat". In
1894 and 1895 he filed patents and addenda in various countries for his Diesel engine; the firstpatents were issued in Spain (No.16,654) France (No.243,531) and Belgium (No.113,139) in
December 1894, and in Germany (No.86,633) in 1895 and the United States (No.608,845) in
1898. He operated his first successful engine in 1897. His engine was the first to prove that fuel
could be ignited without a spark.
-
8/7/2019 elective 2 term paper...toti
3/20
Though best known for his invention of the pressure-ignited heat engine that bears his name,
Rudolf Diesel was also a well-respected thermal engineer and a social theorist. Diesel's
inventions have three points in common: they relate to heat transfer by natural physical processes
or laws; they involve markedly creative mechanical design; and they were initially motivated by
the inventor's concept of sociological needs. Rudolf Diesel originally conceived the diesel engine
to enable independent craftsmen and artisans to compete with industry.
At Augsburg, on August 10, 1893, Rudolf Diesel's prime model, a single 10-foot (3.0 m) iron
cylinder with a flywheel at its base, ran on its own power for the first time. Diesel spent two
more years making improvements and in 1896 demonstrated another model with a theoretical
efficiency of 75 percent, in contrast to the 10 percent efficiency of the steam engine. By 1898,
Diesel had become a millionaire. His engines were used to power pipelines, electric and water
plants, automobiles and trucks, and marine craft. They were soon to be used in mines, oil fields,
factories, and transoceanic shipping.
Types and Characteristics:
Two-stroke diesel engine
A two-stroke engine is an internal combustion engine that completes thethermodynamic cycle in
two movements of the piston (compared to twice that number for a four-stroke engine). This
increased efficiency is accomplished by using the beginning of the compression stroke and the
end of the combustion stroke to perform simultaneously the intake and exhaust (or scavenging)
functions. In this way two-stroke engines often provide strikingly high specific power. Gasoline
(spark ignition) versions are particularly useful in lightweight (portable) applications such as
chainsaws and the concept is also used in diesel compression ignition engines in large and non-
weight sensitive applications such as ships and locomotives.
Four-stroke diesel engine
The four strokes refer to intake, compression, combustion (power), and exhaust strokes that
occur during two crankshaft rotations per working cycle of the gasoline engine and diesel engine.
-
8/7/2019 elective 2 term paper...toti
4/20
The cycle begins at Top Dead Center (TDC), when the piston is farthest away from the axis of
thecrankshaft. A stroke refers to the full travel of the piston from Top Dead Center (TDC) to
Bottom Dead Center (BDC). (See Dead centre.)
Diesel Applications:
Passenger cars
Diesel engines have long been popular in bigger cars and this is spreading to smaller cars.
Diesel engines tend to be more economical at regular driving speeds and are much better at city
speeds. Their reliability and life-span tend to be better (as detailed). Some 40% or more of all
cars sold in Europe are diesel-powered where they are considered a low CO2 option. Mercedes-
Benz in conjunction with Robert Bosch GmbH produced diesel-powered passenger cars starting
in 1936 and very large numbers are used all over the world (often as "Grande Taxis" in the Third
World).
Railroad rolling stock
Diesel engines have eclipsed steam engines as the prime mover on all non-electrified
railroads in the industrialized world. The first diesel locomotives appeared in the early 20th
century, and diesel multiple units soon after.
While electric locomotives have now replaced the diesel locomotive almost completely
on passenger traffic in Europe and Asia, diesel is still today very popular for cargo-
hauling freight trains and on tracks where electrification is not feasible.
Most modern diesel locomotives are actually diesel-electric locomotives: the diesel
engine is used to power an electric generator that in turn powers electric traction engines with no
mechanical connection between diesel engine and traction.
Other transport uses
Larger transport applications (trucks, buses, etc.) also benefit from the diesel's reliability
and high torque output. Diesel displaced paraffin (or tractor vaporising oil, TVO) in most parts
of the world by the end of the 1950s with the U.S. following some 20 years later.
-
8/7/2019 elective 2 term paper...toti
5/20
In merchant ships and boats, the same advantages apply with the relative safety of diesel
fuel an additional benefit. The German pocket battleships were the largest diesel warships, but
the German torpedo-boats known as E-boats (Schnellboot) of the Second World War were also
diesel craft. Conventional submarines have used them since before the First World War, relying
on the almost total absence of carbon monoxide in the exhaust. American World War II diesel-
electric submarines operated on two-stroke cycle as opposed to the four-stroke cycle that other
navies used.
Military fuel standardisation
NATO has a single vehicle fuel policy and has selected diesel for this purpose. The use of
a single fuel simplifies wartime logistics. NATO and the United States Marine Corps have even
been developing a diesel military motorcycle based on a Kawasaki off road motorcycle, with a
purpose designed naturally aspirated direct injection diesel at Cranfield University in England, to
be produced in the USA, because motorcycles were the last remaining gasoline-powered vehicle
in their inventory. Before this, a few civilian motorcycles had been built using adapted stationary
diesel engines, but the weight and cost disadvantages generally outweighed the efficiency gains.
Current and Future Developments
As of 2008, many common rail and unit injection systems already employ new injectors
using stacked piezoelectric wafers in lieu of a solenoid, giving finer control of the injectionevent. Variable geometry turbochargers have flexible vanes, which move and let more air into
the engine depending on load. This technology increases both performance and fuel economy.
Boost lag is reduced as turbo impeller inertia is compensated for.
Accelerometer pilot control (APC) uses an accelerometer to provide feedback on the
engine's level of noise and vibration and thus instruct the ECU to inject the minimum amount of
fuel that will produce quiet combustion and still provide the required power (especially while
idling).
The next generation of common rail diesels is expected to use variable injection
geometry, which allows the amount of fuel injected to be varied over a wider range, and variable
valve timing (see Mitsubishi's 4N13 diesel engine) similar to that on petrol engines. Particularly
in the United States, coming tougher emissions regulations present a considerable challenge to
-
8/7/2019 elective 2 term paper...toti
6/20
diesel engine manufacturers. Ford's HyTrans Project has developed a system which starts the
ignition in 400 ms, saving a significant amount of fuel on city routes, and there are other
methods to achieve even more efficient combustion, such as homogeneous charge compression
ignition, being studied.
Figure:
Geothermal Elements
Definition:
Geothermal energy (from the Greek roots geo, meaning earth, and thermos, meaning heat)
is power extracted from heat stored in the earth. This geothermal energyoriginates from theoriginal formation of the planet, from radioactive decay of minerals, from volcanic activity and
from solar energy absorbed at the surface. It has been used for bathing since Paleolithic times
and for space heating since ancient Roman times, but is now better known for generating
electricity. Worldwide, about 10,715 megawatts(MW) of geothermal power is online in 24
-
8/7/2019 elective 2 term paper...toti
7/20
countries. An additional 28 gigawatts of directgeothermal heating capacity is installed for district
heating, space heating, spas, industrial processes, desalination and agricultural applications.[1]
Geothermal power is cost effective, reliable, sustainable, and environmentally friendly, but has
historically been limited to areas near tectonic plate boundaries. Recent technological advanceshave dramatically expanded the range and size of viable resources, especially for applications
such as home heating, opening a potential for widespread exploitation. Geothermal wells release
greenhouse gases trapped deep within the earth, but these emissions are much lower per energy
unit than those of fossil fuels. As a result, geothermal power has the potential to help
mitigate global warming if widely deployed in place of fossil fuels.
History:
Hot springs have been used for bathing at least since paleolithic times. The oldest known spa is a
stone pool on Chinas Lisan mountain built in the Qin dynasty in the 3rd century BC, at the same
site where the Huaqing Chi palace was later built. In the first century AD, Romans
conquered Aquae Sulis, now Bath, Somerset, England, and used the hot springs there to
feedpublic baths and underfloor heating. The admission fees for these baths probably represent
the first commercial use of geothermal power. The world's oldest geothermal district heating
system inChaudes-Aigues, France, has been operating since the 14th century. The earliest
industrial exploitation began in 1827 with the use of geyser steam to extract boric
acid from volcanic mud inLarderello, Italy.
Application:
In the geothermal industry, low temperature means temperatures of 300 F (149 C) or less.
Low-temperature geothermal resources are typically used in direct-use applications, such
as district heating, greenhouses, fisheries, mineral recovery, and industrial process heating.
However, some low-temperature resources can generate electricity using binary cycle electricity
generating technology.[8]
-
8/7/2019 elective 2 term paper...toti
8/20
Approximately 70 countries made direct use of 270 petajoules (PJ) of geothermal heating in
2004. More than half went for space heating, and another third for heated pools. The remainder
supported industrial and agricultural applications. Global installed capacity was 28 GW, but
capacity factors tend to be low (30% on average) since heat is mostly needed in winter. The
above figures are dominated by 88 PJ of space heating extracted by an estimated
1.3 million geothermal heat pumps with a total capacity of 15 GW.[1] Heat pumps for home
heating are the fastest-growing means of exploiting geothermal energy, with a global annual
growth rate of 30% in energy production.[9]
Direct heating is far more efficient than electricity generation and places less demanding
temperature requirements on the heat resource. Heat may come from co-generation via a
geothermal electrical plant or from smaller wells or heat exchangers buried in shallow ground.
As a result, geothermal heating is economic at many more sites than geothermal electricity
generation. Where natural hot springs are available, the heated water can be piped directly
into radiators. If the ground is hot but dry, earth tubes or downhole heat exchangers can collect
the heat. But even in areas where the ground is colder than room temperature, heat can still be
extracted with a geothermal heat pump more cost-effectively and cleanly than by conventional
furnaces.[10] These devices draw on much shallower and colder resources than traditional
geothermal techniques, and they frequently combine a variety of functions, including air
conditioning, seasonal energy storage, solar energycollection, and electric heating. Geothermal
heat pumps can be used for space heating essentially anywhere.
Geothermal heat supports many applications. District heating applications use networks of piped
hot water to heat many buildings across entire communities. In Reykjavk, Iceland, spent water
from the district heating system is piped below pavement and sidewalks to
meltsnow.[11]
Geothermal desalination has been demonstrated.
Performance Evaluation:
Geothermal power requires no fuel (except for pumps), and is therefore immune to fuel cost
fluctuations, but capital costs are significant. Drilling accounts for over half the costs, and
exploration of deep resources entails significant risks. A typical well doublet (extraction and
-
8/7/2019 elective 2 term paper...toti
9/20
injection wells) in Nevada can support 4.5 megawatts (MW) and costs about $10 million to drill,
wit
h a
20
%
fail
ure
rate
.
In
tota
l,
elec
trical plant construction and well drilling cost about 2-5 million per MW of electrical capacity,
while the breakeven price is 0.04-0.10 per kWh.[18] Enhanced geothermal systems tend to be
on the high side of these ranges, with capital costs above $4 million per MW and breakeven
above $0.054 per kWh in 2007.[19] Direct heating applications can use much shallower wells
with lower temperatures, so smaller systems with lower costs and risks are feasible. Residential
geothermal heat pumps with a capacity of 10 kilowatt (kW) are routinely installed for around
$13,000 per kilowatt. District heating systems may benefit from economies of scale if demand
is geographically dense, as in cities, but otherwise piping installation dominates capital costs.
The capital cost of one such district heating system in Bavaria was estimated at somewhat over
1 million per MW.[20] Direct systems of any size are much simpler than electric generators and
have lower maintenance costs per kWh, but they must consume electricity to run pumps and
compressors. Some governments subsidize geothermal projects.
Figure:
-
8/7/2019 elective 2 term paper...toti
10/20
Fuel Systems
Definition:
The function of the fuel system is to store and supply fuel to the cylinder chamber where it can
be mixed with air, vaporized, and burned to produce energy. The fuel, which can be
either gasoline or diesel is stored in a fuel tank. A fuel pump draws the fuel from
the tank through fuel lines and delivers it through a fuel filter to either a carburetor or fuel
injector, then delivered to the cylinder chamber for combustion.
GASOLINE
Gasoline is a complex blend of carbon and hydrogen compounds. Additives are then added to
improve performance. All gasoline is basically the same, but no two blends are identical. The
two most important features of gasoline are volatility and resistance to knock (octane). Volatility
is a measurement of how easily the fuel vaporizes. If the gasoline does not vaporize completely,
it will not burn properly (liquid fuel will not burn).
If the gasoline vaporizes too easily the mixture will be too lean to burn properly. Since high
temperatures increase volatility, it is desirable to have a low volatility fuel for warm
temperatures and a high volatility fuel for cold weather. The blends will be different for summer
and winter fuels. Vapor lock which was a persistent problem years ago, exists very rarely today.
-
8/7/2019 elective 2 term paper...toti
11/20
In today's cars the fuel is constantly circulating from the tank, through the system and back to the
tank. The fuel does not stay still long enough to get so hot that it begins to vaporize. Resistance
to knock or octane is simply the temperature the gas will burn at. Higher octane fuel requires a
higher temperature to burn. As compression ratio or pressure increases so does the need for
higher octane fuel. Most engines today are low compression engines therefore requiring a lower
octane fuel (87). Any higher octane than required is just wasting money. Other factors that affect
the octane requirements of the engine are: air/fuel ratio, ignition timing, engine temperature, and
carbon build up in the cylinder. Many automobile manufacturers have
installed exhaust gas recirculation systems to reduce cylinder chamber temperature. If these
systems are not working properly, the car will have a tendency to knock. Before switching to a
higher octane fuel to reduce knock, make sure to have these other causes checked.
DIESEL
Diesel fuel, like gasoline is a complex blend of carbon and hydrogen compounds. It too requires
additives for maximum performance. There are two grades of diesel fuel used in automobiles
today: 1-D and 2-D. Number 2 diesel fuel has a lower volatility and is blended for higher loads
and steady speeds, therefore works best in large truck applications. Because number 2 diesel fuel
is less volatile, it tends to create hard starting in cold weather. On the other hand number 1 diesel
is more volatile, and therefore more suitable for use in an automobile, where there is constant
changes in load and speed. Since diesel fuel vaporizes at a much higher temperature than
gasoline, there is no need for a fuel evaporation control system as with gasoline. Diesel fuels are
rated with a cetane number rather than an octane number. While a higher octane of gasoline
indicates resistance to ignition, the higher cetane rating of diesel fuel indicates the ease at which
the fuel will ignite. Most number 1 diesel fuels have a cetane rating of 50, while number 2 dieselfuel have a rating of 45. Diesel fuel emissions are higher in sulfur, and lower in carbon monoxide
and hydrocarbons than gasoline and are subject to different emission testing standards.
-
8/7/2019 elective 2 term paper...toti
12/20
FUEL TANK
Tank location and design are always a compromise with available space. Most automobiles have
a single tank located in the rear of the vehicle. Fuel tanks today have internal baffles to prevent
the fuel from sloshing back and forth. If you hear noises from the rear on acceleration and
deceleration the baffles could be broken. All tanks have a fuel filler pipe, a fuel outlet line to the
engine and a vent system. All catalytic converter cars are equipped with a filler pipe restrictor so
that leaded fuel, which is dispensed from a thicker nozzle, cannot be introduced into the fuel
system. All fuel tanks must be vented. Before 1970, fuel tanks were vented to the atmosphere,
emitting hydrocarbon emissions. Since 1970 all tanks are vented through a charcoal canister, into
the engine to be burned before being released to the atmosphere. This is called evaporative
emission control and will be discussed further in the emission control section. Federal law
requires that all 1976 and newer cars have vehicle rollover protection devices to prevent fuel
spills.
FUEL LINES
Steel lines and flexible hoses carry the fuel from the tank to the engine. When servicing or
replacing the steel lines, copper or aluminum must never be used. Steel lines must be replaced
with steel. When replacing flexible rubber hoses, proper hose must be used. Ordinary rubber
such as used in vacuum or water hose will soften and deteriorate. Be careful to route all hoses
away from the exhaust system.
FUEL PUMPS
Two types of fuel pumps are used in automobiles; mechanical and electric. All fuel injected cars
today use electric fuel pumps, while most carbureted cars use mechanical fuel pumps.
Mechanical fuel pumps are diaphragm pumps, mounted on the engine and operated by an
-
8/7/2019 elective 2 term paper...toti
13/20
eccentric cam usually on the camshaft. A rocker arm attached to the eccentric moves up and
down flexing the diaphragm and pumping the fuel to the engine. Because electric pumps do not
depend on an eccentric for operation, they can be located anywhere on the vehicle. In fact they
work best when located near the fuel tank.
Many cars today, locate the fuel pump inside the fuel tank. While mechanical pumps operate on
pressures of 4-6 psi (pounds per square inch), electric pumps can operate on pressures of 30-40
psi. Current is supplied to the pump immediately when the key is turned. This allows for constant
pressure on the system for immediate starting. Electric fuel pumps can be either low pressure or
high pressure. These pumps look identical, so be careful when replacing a fuel pump that the
proper one is used. Fuel pumps are rated by pressure and volume. When
checking fuel pump operation, both specifications must be checked and met.
FUEL FILTERS
The fuel filter is the key to a properly functioning fuel delivery system. This is more true with
fuel injection than with carbureted cars. Fuel injectors are more susceptible to damage from dirt
because of their close tolerances, but also fuel injected cars use electric fuel pumps. When the
filter clogs, the electric fuel pump works so hard to push past the filter, that it burns itself up.
Most cars use two filters. One inside the gas tank and one in a line to the fuel injectors or
carburetor. Unless some severe and unusual condition occurs to cause a large amount of dirt to
enter the gas tank, it is only necessary to replace the filter in the line.
Types:
Mechanical
The term Mechanical when applied to fuel injection is used to indicate that metering
functions of the fuel injection (how the correct amount of fuel for any given situation is
determined and delivered) is not achieved electronically but rather through mechanical means
alone.
-
8/7/2019 elective 2 term paper...toti
14/20
-
8/7/2019 elective 2 term paper...toti
15/20
information about the Bendix system in December 1956 was followed in March 1957 by a price
bulletin that pegged the option at US$395, but due to supplier difficulties, fuel-injected Rebels
would only be available after June 15. This was to have been the first production EFI engine, but
Electrojector's teething problems meant only pre-production cars were so equipped: thus, very
few cars so equipped were ever sold and none were made available to the public. The EFI system
in the Rambler was a far more-advanced setup than the mechanical types then appearing on the
market and the engines ran fine in warm weather, but suffered hard starting in cooler
temperatures.
Figure:
-
8/7/2019 elective 2 term paper...toti
16/20
DIESEL POWER PLANT
Diesel plants are more efficient than any other heat engine of comparable size. Diesel
power plant issuitable for small and medium outputs (2-50MW). These power plants are suitable
for peak load power requirements, fuel cost are favour and where the water scarcity present. Itcan be started very quickly and immediately generate the electric power.
The major components of the plant are:
a) Engine
Engine is the heart of a diesel power plant. Engine is directly connected through a gear
box to the generator. Generally two-stroke engines are used for power generation. Now a day,
advanced super & turbo charged high speed engines are available for power production.
b) Air supply system
Air inlet is arranged outside the engine room. Air from the atmosphere is filtered by air
filter and conveyed to the inlet manifold of engine. In large plants supercharger/turbocharger is
used for increasing the pressure of input air which increases the power output.
-
8/7/2019 elective 2 term paper...toti
17/20
c) Exhaust System
This includes the silencers and connecting ducts. The heat content of the exhaust gas is
utilized in a turbine in a turbocharger to compress the air input to the engine.
d) Fuel System
Fuel is stored in a tank from where it flows to the fuel pump through a filter. Fuel is
injected to the engine as per the load requirement.
e) Cooling system
This system includes water circulating pumps, cooling towers, water filter etc. Cooling
water is circulated through the engine block to keep the temperature of the engine in the safe
range.
f) Lubricating system
Lubrication system includes the air pumps, oil tanks, filters, coolers and pipe lines.
Lubricant is given to reduce friction of moving parts and reduce the wear and tear of the engine
parts.
g) Starting System
There are three commonly used starting systems, they are;
1) A petrol driven auxiliary engine,
2) Use of electric motors,
3)Use of compressed air from an air compressor at a pressure of 20 Kg/cm.
h) Governing system
The function of a governing system is to maintain the speed of the engine constant
irrespective of load on the plant. This is done by varying fuel supply to the engine according to
load.
Advantages of diesel power plants
1. More efficient than thermal plant
2. Design, Layout etc are simple and cheap
3. Part load efficiency is very high
4. It can be started quickly
5. Simple & easy maintenance
6. No problem with fuel & dust handling
-
8/7/2019 elective 2 term paper...toti
18/20
7. It can be located in the heart of town
8. Less cooling water required.
Disadvantages
1. There is a limitation for size of a diesel engine
2. Life of plant is comparatively less
3. Noise pollution is very high
4. Repair cost is very high
5. High lubrication cost
Steam is used for heating and process work as it isan ideal carrier of heat. Its three
main advantagesas a heat transfer medium are as follows:
It transfers heat at constant temperature.This is extremely useful whendealing with
heat sensitive materials.The temperature of steam is dependentupon the steam
pressure.This results ina simple method of temperature control.It is compact in terms of
heat content perunit volume.This means heat can heconveyed in simple piping systems.
Steam has many uses in industry. It is used for process heating, pressure control,
mechanical drive, component separation and is a source of water for many process reactions.
Steam has many performance advantages that make it an attractive means of delivering energy
including low toxicity, ease of transportability, high efficiency, high heat capacity and low cost
relative to other alternatives.
Steam systems provide process heating, pressure control, mechanical drive, component
separation, and are a source of water for many process reactions. In 1994, US industries used
about 5,676 trillion Btu of steam energy, which represents about 34 percent of the total energy
used in industrial applications for product output 1. Steam use is especially significant in the pulp
and paper (2,197 trillion Btu), chemical (1,855 trillion Btu), and petroleum refining (1,373
trillion Btu), representing 83 percent, 57 percent, and 42 percent respectively of the total energy
used by theses industries.
-
8/7/2019 elective 2 term paper...toti
19/20
Figure:
-
8/7/2019 elective 2 term paper...toti
20/20