Flight around the world without fuel (Amazing...)


 Flight around the world without fuel



Last year unveiled its first solar aircraft in the world.
Renewable energies are a major thrust of the Forum on the international media about climate change and the media, organized by Deutsche Welle. In this context, view the scale model of a plane preparing for a tour around the world using solar energy only.

Many of the obvious things in our day was, and for several centuries, from the seventh impossible. For example, the conquest of space and the ability to fly and move quickly from one continent to another. Without the presence of people believe in the possibility of realizing the dream of flight and walked the opposite beliefs in their time, the sky has remained to this day free of the aircraft.

This is the philosophy that believes in the famous navigator Swiss Bertrand Piccard, who succeeded in 1999 flew around the world in a balloon, he said in a lecture at the Global Media Forum, organized by Deutsche Welle in Bonn. Speaking about this experience "said Picard" The heart arrived in the throat "fear when the balloon above the Atlantic Ocean, for fear that performs fuel drops the balloon in the ocean, also noted that the wind was the captain of the airship real, not human because they are heading to where you want.

This experience made him think of a new innovation can fly around the world without fear of depletion of fuel and are to be determined is the same direction he wants. In 2004, the idea of the invention of the engine with solar energy, has sent 40 companies engines powered by solar energy to Picard, which forces convinced the possibility of achieving his dream. In 2007, began to Picard and his colleague Andre Borcburg work on the manufacture aircraft Solar, an aircraft can fly card derived from the beam the sun without the need for kerosene, such as other aircraft. Two years later managed to fly his plane Picard solar to be the first person to fly an aircraft without the "fuel" in the air.





The length of the wings 63 meters long and 40 cm has development took 6 years.

Flight of the day and night with solar energy

The problem of the new aircraft is its ability to fly during the day and only having to drop before sundown, and they can fly a long time under the clouds that obscure the sun for.

But in the past three years cut André Picard and fellow Borcburg an advanced stage in the development of solar plane as they prepare this year to experience the first of its kind in the world. The Picard intends to fly for 36 continuous hours flew the carbon-fiber reinforced and not more than the weight of 1600 kg. This experiment was made possible after the progress witnessed by the battery technology capable of storing electric energy or wind power Kkahraba to use when needed. Weighing up the battery to 450 kilograms, equivalent to a quarter of the weight of the aircraft. The wing aircraft amounts to 63,4 meters-foot panels were installed solar panels on them an area of 200 square meters.

Flight around the world after two years




Navigator Swiss Bertrand Piccard speaks about his project to an audience World Media Forum in Bonn.

If successful the flying experience for two days and one night this year will begin Picard and his colleague in the planning for a trip Stdechlhma history of the wider doors. The plan is to fly around the world with a stop over only five times, once in every continent, in 2012 Solar plane. Picard hopes to succeed in his venture to prove to the world could be dispensed with once for fossil fuels, including oil, gas and coal. He says, "do not convince me not to be dispensed with once and for fossil fuels, if managed aircraft from flying at night as flying during the day without the kerosene and the use of solar power only," This is the philosophy that believes in Picard, it seeks to validate through flight may constitute a qualitative leap in the history of humanity.

Aircraft Design Projects for engineering students(download)

Aircraft Design Projects for engineering students




Introduction
It is tempting to title this book ‘Flights of Fancy’ as this captures the excitement and
expectations at the start of a new design project. The main objective of this book is
to try to convey this feeling to those who are starting to undertake aircraft conceptual
design work for the first time. This often takes place in an educational or industrial
training establishment. Too often, in academic studies, the curiosity and fascination of
project work is lost under a morass of mathematics, computer programming, analytical
methods, project management, time schedules and deadlines. This is a shame as there
are very few occasions in your professional life that you will have the chance to let your
imagination and creativity flow as freely as in these exercises. As students or young
engineers, it is advisable to make the most of such opportunities.
When university faculty or counsellors interview prospective students and ask why
they want to enter the aeronautics profession, the majority will mention that they want
to design aircraft or spacecraft. They often tell of having drawn pictures of aeroplanes
since early childhood and they imagine themselves, immediately after graduation, producing
drawings for the next generation of aircraft. During their first years in the
university, these young men and women are often less than satisfied with their basic
courses in science, mathematics, and engineering as they long to ‘design’ something.
When they finally reach the all-important aircraft design course, for which they have
yearned for so long, they are often surprised. They find that the process of design
requires far more than sketching a pretty picture of their dream aircraft and entering
the performance specifications into some all-purpose computer program which will
print out a final design report.
Design is a systematic process. It not only draws upon all of the student’s previous
engineering instruction in structures, aerodynamics, propulsion, control and other
subjects, but also, often for the first time, requires that these individual academic
subjects be applied to a problem concurrently. Students find that the best aerodynamic
solution is not equated to the best structural solution to a problem. Compromises
must be made. They must deal with conflicting constraints imposed on their design
by control requirements and propulsion needs. They may also have to deal with real
world political, environmental, ethical, and human factors. In the end, they find they
must also do practical things like making sure that their ideal wing will pass through
the hangar door!


An overview of the book
This book seeks to guide the student through the preliminary stages of the aircraft
design process. This is done by both explaining the process itself (Chapters 1 and 2)
and by providing a variety of examples of actual student design projects (Chapters 3
to 10). The projects have been used as coursework at universities in the UK and the US.
It should be noted that the project studies presented are not meant to provide a ‘fill in
the blank’ template to be used by future students working on similar design problems
but to provide insight into the process itself. Each design problem, regardless of how
similar it may appear to an earlier aircraft design, is unique and requires a thorough
and systematic investigation. The project studies presented in this book merely serve
as examples of how the design process has been followed in the past by other teams
faced with the task of solving a unique problem in aircraft design.
It is impossible to design aircraft without some knowledge of the fundamental theories
that influence and control aircraft operations. It is not possible to include such
information in this text but there are many excellent books available which are written
to explain and present these theories. A bibliography containing some of these books
and other sources of information has been added to the end of the book. To understand
the detailed calculations that are described in the examples it will be necessary to use
the data and theories in such books. Some design textbooks do contain brief examples
on how the analytical methods are applied to specific aircraft. But such studies are
mainly used to support and illustrate the theories and do not take an overall view of
the preliminary design process.
The initial part of the book explains the preliminary design process. Chapter 1 briefly
describes the overall process by which an aircraft is designed. It sets the preliminary
design stages into the context of the total transformation from the initial request for
proposal to the aircraft first flight and beyond. Although this book only deals with
the early stages of the design process, it is necessary for students to understand the
subsequent stages so that decisions are taken wisely. For example, aircraft design is
by its nature an iterative process. This means that estimates and assumptions have
sometimes to be made with inadequate data. Such ‘guesstimates’ must be checked when
more accurate data on the aircraft is available. Without this improvement to the fidelity
of the analytical methods, subsequent design stages may be seriously jeopardized.
Chapter 2 describes, in detail, the work done in the early (conceptual) design process.
It provides a ‘route map’ to guide a student from the initial project brief to the validated
‘baseline’ aircraft layout. The early part of the chapter includes sections that deal with
‘defining and understanding the problem’, ‘collecting useful information’ and ‘setting
the aircraft requirements’. This is followed by sections that show how the initial aircraft
configuration is produced. Finally, there are sections illustrating how the initial aircraft
layout can be refined using constraint analysis and trade-off studies. The chapter ends
with a description of the ‘aircraft type specification’. This report is commonly used to
collate all the available data about the aircraft. This is important as the full geometrical
description and data will be needed in the detailed design process that follows.
Chapter 3 introduces the seven project studies that follow (Chapters 4 to 10). It
describes each of the studies and provides a format for the sequence of work to be
followed in some of the studies. The design studies are not sequential, although the
earlier ones are shown in slightly more detail. It is possible to read any of the studies
separately, so a short description of each is presented.
Chapters 4 to 10 inclusive contain each of the project studies. The projects are selected
from different aeronautical applications (general aviation, civil transports, military
aircraft) and range from small to heavy aircraft. For conciseness of presentation the
detailed calculations done to support the final designs have not been included in these
chapters but the essential input values are given so that students can perform their
own analysis. The projects are mainly based on work done by students on aeronautical
engineering degree courses. One of the studies is from industrial work and some have
been undertaken for entry to design competitions. Each study has been selected to
illustrate a different aspect of preliminary design and to illustrate the varied nature of
aircraft conceptual design.
The final chapter (11) offers guidance on student design work. It presents a set of
questions to guide students in successfully completing an aircraft design project. It
includes some observations about working in groups. Help is also given on the writing
of technical reports and making technical presentations.

Engineering units of measurement
Experience in running design projects has shown that students become confused by
the units used to define parameters in aeronautics. Some detailed definitions and conversions
are contained in Appendix A at the end of the book and a quick résumé is
given here.
Many different systems of measurement are used throughout the world but two have
become most common in aeronautical engineering. In the US the now inappropriately
named ‘British’ system (foot, pound and second) is widely used. In the UK and over
most of Europe, System International (SI) (metres, newton and second) units are standard.
It is advised that students only work in one system. Confusion (and disaster) can
occur if they are mixed. The results of the design analysis can be quoted in both types
of unit by applying standard conversions. The conversions below are typical:
1 inch = 25.4 mm
1 sq. ft = 0.0929 sq. m
1 US gal = 3.785 litres
1 US gal = 0.833 Imp. gal
1 statute mile = 1.609 km
1 ft/s = 0.305 m/s
1 knot = 1.69 ft/s
1 pound force = 4.448 newtons
1 horsepower = 745.7 watts
1 foot = 0.305 metres
1 cu. ft = 28.32 litres
1 Imp. gal = 4.546 litres
1 litre = 0.001 cubic metres
1 nautical mile = 1.852 km
1 knot = 0.516 m/s
1 knot = 1.151 mph
1 pound mass = 0.454 kilogram
1 horsepower = 550 ft lb/s
To avoid confusing pilots and air traffic control, some international standardization of
units has had to be accepted. These include:
Aircraft altitude – feet Aircraft forward speed – knots∗
Aircraft range – nautical miles Climb rate – feet per minute
(∗ Be extra careful with the definition of units used for aircraft speed as pilots like to use
airspeed in IAS (indicated airspeed as shown on their flight instruments) and engineers
like TAS (true airspeed, the speed relative to the ambient air)).
Fortunately throughout the world, the International Standard Atmosphere (ISA)
has been adopted as the definition of atmospheric conditions. ISA charts and data
can be found in most design textbooks. In this book, which is aimed at a worldwide
readership, where possible both SI and ‘British’ units have been quoted. Our apologies
if this confuses the text in places.




Design methodology

The start of the design process requires the recognition of a ‘need’. This normally comes
from a ‘project brief’ or a ‘request for proposals (RFP)’. Such documents may come
from various sources:
• Established or potential customers.
• Government defence agencies.
• Analysis of the market and the corresponding trends from aircraft demand.
• Development of an existing product (e.g. aircraft stretch or engine change).
• Exploitation of new technologies and other innovations from research and
development.
It is essential to understand at the start of the study where the project originated and to
recognise what external factors are influential to the design before the design process
is started.
At the end of the design process, the design team will have fully specified their design
configuration and released all the drawings to the manufacturers. In reality, the design
process never ends as the designers have responsibility for the aircraft throughout its
operational life. This entails the issue of modifications that are found essential during
service and any repairs and maintenance instructions that are necessary to keep the
aircraft in an airworthy condition.
The design method to be followed from the start of the project to the nominal end can
be considered to fall into three main phases. These phases are illustrated in Figure 1.1.
The preliminary phase (sometimes called the conceptual design stage) starts with the
project brief and ends when the designers have found and refined a feasible baseline
design layout. In some industrial organisations, this phase is referred to as the ‘feasibility
study’. At the end of the preliminary design phase, a document is produced which
contains a summary of the technical and geometric details known about the baseline
design. This forms the initial draft of a document that will be subsequently revised
to contain a thorough description of the aircraft. This is known as the aircraft ‘Type
Specification’.
The next phase (project design) takes the aircraft configuration defined towards
the end of the preliminary design phase and involves conducting detailed analysis to
improve the technical confidence in the design. Wind tunnel tests and computational
fluid dynamic analysis are used to refine the aerodynamic shape of the aircraft. Finite
element analysis is used to understand the structural integrity. Stability and control
analysis and simulations will be used to appreciate the flying characteristics. Mass and
balance estimations will be performed in increasingly fine detail. Operational factors
(cost, maintenance and marketing) and manufacturing processes will be investigated


to determine what effects these may have on the final design layout. All these investigations
will be done so that the company will be able to take a decision to ‘proceed
to manufacture’. To do this requires knowledge that the aircraft and its novel features
will perform as expected and will be capable of being manufactured in the timescales
envisaged. The project design phase ends when either this decision has been taken or
when the project is cancelled.
The third phase of the design process (detail design) starts when a decision to build
the aircraft has been taken. In this phase, all the details of the aircraft are translated
into drawings, manufacturing instructions and supply requests (subcontractor agreements
and purchase orders). Progressively, throughout this phase, these instructions
are released to the manufacturers.
Clearly, as the design progresses from the early stages of preliminary design to the
detail and manufacturing phases the number of people working on the project increases
rapidly. In a large company only a handful of people (perhaps as few as 20) will be
involved at the start of the project but towards the end of the manufacturing phase
several thousand people may be employed. With this build-up of effort, the expenditure
on the project also escalates as indicated by the curved arrow on Figure 1.1.
Some researchers1 have demonstrated graphically the interaction between the cost
expended on the project, the knowledge acquired about the design and the resulting
reduction in the design freedom as the project matures. Figure 1.2 shows a typical
distribution. These researchers have argued for a more analytical understanding of the
requirement definition phase. They argue that this results in an increased understanding
of the effects of design requirements on the overall design process. This is shown
on Figure 1.2 as process II, compared to the conventional methods, process I. Understanding
these issues will increase design flexibility, albeit at a slight increase in initial
expenditure. Such analytical processes are particularly significant in military, multirole,
and international projects. In such case, fixing requirements too firmly and too
early, when little is known about the effects of such constraints, may have considerable
cost implications.
Much of the early work on the project is involved with the guarantee of technical
competence and efficiency of the design. This ensures that late changes to the design


layout are avoided or, at best, reduced. Such changes are expensive and may delay the
completion of the project. Managers are eager to validate the design to a high degree
of confidence during the preliminary and project phases. A natural consequence of this
policy is the progressive ‘freezing’ of the design configuration as the project matures.
In the early preliminary design stages any changes can (and are encouraged to) be
considered, yet towards the end of the project design phase only minor geometrical
and system modifications will be allowed. If the aircraft is not ‘good’ (well engineered)
by this stage then the project and possibly the whole company will be in difficulty.
Within the context described above, the preliminary design phase presents a significant
undertaking in the success of the project and ultimately of the company.
Design project work, as taught at most universities, concentrates on the preliminary
phase of the design process. The project brief, or request for proposal, is often used to
define the design problem. Alternatively, the problem may originate as a design topic
in a student competition sponsored by industry, a government agency, or a technical
society. Or the design project may be proposed locally by a professor or a team of
students. Such design project assignments range from highly detailed lists of design
objectives and performance requirements to rather vague calls for a ‘new and better’
replacement for existing aircraft. In some cases student teams may even be asked to
develop their own design objectives under the guidance of their design professor.
To better reflect the design atmosphere in an industry environment, design classes at
most universities involve teams of students rather than individuals. The use of multidisciplinary
design teams employing students from different engineering disciplines is
being encouraged by industry and accreditation agencies.
The preliminary design process presented in this text is appropriate to both the individual
and the team design approach although most of the cases presented in later
chapters involved teams of design students. While, at first thought, it may appear that
the team approach to design will reduce the individual workload, this may not be so.

The interpersonal dynamics of working in a team requires extra effort. However, this
greatly enhances the design experience and adds team communications, management
and interpersonnel interaction to the technical knowledge gained from the project work.
It is normal in team design projects to have all students conduct individual initial
assessments of the design requirements, study comparable aircraft, make initial estimates
for the size of their aircraft and produce an initial concept sketch. The full team will
then begin its task by examining these individual concepts and assessing their merits
as part of their team concept selection process. This will parallel the development of
a team management plan and project timeline. At this time, the group will allocate
various portions of the conceptual design process to individuals or small groups on
the team.
At this point in this chapter, a word needs to be said about the role of the computer
in the design process. It is natural that students, whose everyday lives are filled with
computer usage for everything from interpersonal communication to the solution of
complex engineering problems, should believe that the aircraft design process is one in
which they need only to enter the operational requirements into some supercomputer
and wait for the final design report to come out of the printer (Figure 1.3).
Indeed, there are many computer software packages available that claim to be ‘aircraft
design programs’ of one sort or another. It is not surprising that students, who have
read about new aircraft being ‘designed entirely on the computer’ in industry, believe
that they will be doing the same. They object to wasting time conducting all of the
basic analyses and studies recommended in this text, and feel that their time would
be much better spent searching for a student version of an all-encompassing aircraft
design code. They believe that this must be available from Airbus or Boeing if only they
can find the right person or web address.
While both simple aircraft ‘design’ codes and massive aerospace industry CAD
programs do exist and do play important roles, they have not yet replaced the basic processes
outlined in this text. Simple software packages which are often available freely at
various locations on the Internet, or with many modern aeronautical engineering texts,
can be useful in the specialist design tasks if one understands the assumptions and limitations
implicit in their analysis. Many of these are simple computer codes based on





Download Aircraft Design Projects For Engineering Students Book from here:

Queen Elizabeth Hospital in Summit Innovation

 Queen Elizabeth Hospital in Summit Innovation



I do not think that any one of us, whether young or child like hospitals  atmosphere , from this point  the Queen Elizabeth Hospital in Berlin, create a special section for children and young people living with mental illness, but it's not like you saw a hospital by:





you will not feel that this is a hospital of mental illness when you see this picture , that is the Excellent creativity that the hospital has achived with the help of Dan Perlman agency of creative projects


This project named "Ellis Island" , in this project every chamber was designed with high professionality and take care of accurate details (colors, materials, illuminations ,decorations,...) including giving a sense of security and positive thinking in children and young people, at the same time give them the incentive for creativity and innovation!


The supervisors of Queen Elizabeth Hospital say the project that all of these objectives have been achieved distinction through tours for those who were treated in this place.


This project draws attention to a very serious point, namely, that the biggest problem of the mentally ill lies in the "social stigma" that make society and rejected by discarding them, connecting them sometimes crazy! Ignoring the fact that a large part of mental illness can be treated with any organic disease such as usual!


This Queen Elizabeth Hospital draws attention to a very serious point, namely, that the biggest problem of the mentally ill lies in the "social stigma" that make society and rejected by discarding them, connecting them sometimes crazy! Ignoring the fact that a large part of mental illness can be treated with any organic disease such as usual!

So I think that the most beautiful he has done this project is to notice the mentally ill through the safe reintegration in an environment that is both exhilarating and comfortable make them feel part of this life!

This is another set of Queen Elizabeth Hospital photos:

5- On a Large Industrial Diesel Or Gas Engine (monitoring, start-up ,and preventive maintenance programs,....) - automobile engineering








 in the previous sections we had discuss :

- Classification of Internal Combustion Engines and Engine Components (Course)

- Internal Combustion Engines Components 2 (Course)

 3- Internal Combustion Engines cooling and lubrication system (Course)

 4-crankcase ventilation and induction systems(function, operation, inspection, and service)

 

 

 

 In This  section we will discuss :

- Explain the monitoring, protection and control devices on a large industrial diesel or gas engine,including shutdowns and governing.
- Explain a typical start-up procedure for a large industrial diesel engine, plus the routine
monitoring requirements of a running engine & Start up procedure.
- State the purpose and methods of engine preventive maintenance programs




 SECTION 5



Objective 11
Explain the monitoring, protection and control devices on a large industrial diesel or gas engine,
including shutdowns and governing.

ENGINE MONITORING AND PROTECTION
The systems necessary to keep a large engine running must be continuously monitored.The main systems, which must be monitored, are:
• The lubrication system including oil level, temperature, and pressure
• The cooling system temperatures and pressures
• The fuel system including fuel tank level, fuel filters and fuel injector pressure
• The air intake system including air filter differential pressure
• The exhaust system including temperature and pressure
• The electrical system including voltage, amperage, and charging conditions
• Engine speed
• Turbo or supercharger boost pressure

Engine Sensors and Their Function
Industrial engine control sensors and shutdowns are very important compared to engine
mobile applications. In mobile applications (such as cars), the driver can control the speed
and monitor the gauges and sounds of the engine to make sure all is well. In industrial
applications, there is, usually no one to monitor any functions of the engine. Many early
industrial engines had either no any or very few methods of monitoring the operation of the
engine. Today's engines are well-equipped with many devices and methods of monitoring the
operation of an engine. Electronic sensors can be used to continually monitor the engine.
These sensors have the added feature of recording information that is outside of the normal
operating range of the engine and then storing this as fault codes in the computer module.
(Encoding is the process of converting this information so that it can be understood by the
millwright/operator.)

There are two basic categories for engine monitoring devices. The first type monitors engine
and shuts or slows it down if the conditions become dangerous to the life of the engine. The
other type of monitor senses the engine's operating conditions to provide information to a simple or complex logic device, which may then change the engine's operation.



Engine Shutdown Devices
Engine shutdown devices can tell you what has failed and some panels indicate which
malfunction occurred first. These devices include:

• Shock And Vibration Shutdowns And Monitors,
• Engine Overspeed,
• Crankcase Level Switches,
• Engine Low Oil Pressure Switches,
• Coolant Low Level Switches And
• Tattletale Alarm Panels.

Engine Monitoring Devices
Most engines are equipped with an instrumentation panel that allows the operator or
millwright to make several observations.
• The engine can be monitored for normal conditions on the engine's essential functions.
• When records are kept of the engine's functions, trends can be established to determine
if there is deterioration in the engine's functions.
• Troubleshooting is much easier if recent and current readings of essential engine
functions are available.

Intake Manifold Pressure Sensors
Intake manifold pressure sensors (transducer) are used on engines with lean bum or catalytic
equipment. These sensors are used as feedback to the AFM as an indicator of engine load.

Oxygen Sensors
Oxygen sensors are used to measure the amount of oxygen content that is left in the exhaust
gases after combustion. The sensor is located in the exhaust system just after the exhaust
manifold. The sensor is connected to the air-fuel module (AFM), which controls the fuel
pressure regulator. The oxygen sensor helps the fuel system control to change the fuel
mixture for the best emissions power and economy. The oxygen sensor must reach a
predetermined temperature (approximately 316°P or 600°F) before it sends a signal to the
AFM. The engine may have more than one oxygen sensor. There are some variations in
oxygen sensor types. Some depend only on exhaust temperature while others have heaters to
bring them to temperature as early as possible. Oxygen sensors have an expected life span of
approximately 8000 hours or one year of continuous operation.

There are several types of engine sensors including:
• Coolant temperature sensors help control the amount of fuel needed. The sensors not
only monitor the engine; they are also engine protection devices that warn and/or shut
down the engine at high temperatures.
• Oil temperature sensors serve the same purpose as all other temperature sensors in
that the information is used to protect the engine. The signals are sent to the computer
module so that the appropriate action can be taken.
• A fuel temperature sensor provides a signal as to the fuel's temperature. The control
module utilizes the information to calculate and adjust fuel consumption. Fuel density
is a function of temperature, and these changes allow the engine to operate at peak
efficiency.
• Air intake temperature sensors monitor and react to temperature at either the intake
manifold or the air filter assembly. The information is then used by the computer
module to adjust the fuel amount for the proper ratio.

Pyrometers
Pyrometers (thermocouples) measure the temperature of the exhaust. Some engines have only
one pyrometer to give an indication of overall exhaust temperature; other engines have a
pyrometer on each exhaust port.
Pyrometers can perform several functions. They are used to indicate engine exhaust overall
temperature, but can also be used to indicate the individual temperature of each cylinder. This
is valuable in balancing the load on the engine. The cylinders with the highest temperatures
carry the greatest load.
An exhaust pyrometer should be used any time that an oxygen analyzer is used. The
temperature must be measured for every cylinder in order to confirm proper firing. If
cylinders are misfiring, cool temperatures are recorded at that particular cylinder at the same
time. Because full combustion has not occurred the oxygen analyzer detects higher levels of
oxygen at the exhaust. To correct the problem, the millwright, unaware of the misfiring,
increases the fuel ratio for richer bum, when in fact this causes severe detonation in cylinders
that are not misfiring.

Fluid Levels
Fluid level sensors monitor both high and low levels. When monitoring oil and coolant levels,
warning and/or shutdown devices. are activated to protect the engine. Scrubbers also have
either an automatic drain feature or a monitoring device to warn when liquid levels reach a
point of concern (see the Compressor module on scrubbers).

Air Cleaner Restriction Gauges
Engines are sometimes equipped with an air restriction indicator/sensor. This indicator
provides a warning when the differential pressure reaches a point to indicate it is time an
intake air filter change. This pressure differential is a measure of negative pressure is in
inches of water.

Oil Pressure Sensors
Oil pressure sensors are located in oil lines and monitor pressure during engine operation If
there is a significant reduction in oil pressure the computer receives this signal and shuts
down the engine.

Fuel Pressure Sensors
See the information on fuel gas regulating valves.

Cylinder Pressures and Kiene Indicator Valves
Kiene indicator valves are used in conjunction with pressure indicators to sense pressure at
each individual cylinder. This is done for engine balancing. Another name for this valve is a
cylinder indicator cock.

Detonation Sensors
Detonation sensors are used to measure any degree of detonation and to send that information
to the ignition module. The ignition module then changes the ignition timing to the best
position, based on the operating condition of that cylinder. The detonation sensor is
essentially an accelerometer that measures the vibrations from inside the cylinder. Smaller
engines may only have one sensor, but larger engines have a detonate sensor on each
cylinder. The sensors are usually located near the top of each cylinder.

Pneumatic Engine Control Panels
There are many control panels in the gas field and other installations using pneumatic control
and safety systems. This system can be used as a warning system or a shutdown system and
flags the cause of the shutdown on the panel. The control system is powered by clean, dry air
or gas at moderate pressures. This can be an ideal arrangement for so hazardous locations.
Almost all of the engines in natural gas compressor installations prior to the 1990s were
equipped with these pneumatic control panels. The pneumatic control panels would flag Red
or Green, depending on the status of each control. These panels show:
• Low coolant level,
• Low oil pressure,
• High coolant temperature,
• Engine vibration,
• Compressor vibration,
• Compressor discharge pressure,
• Compressor suction pressure and
• Engine overspeed.

Electronic Engine Control Panels
Engine Turbo Boost Control System
Turbocharged engines use the throttle to control the amount of boost until the engine is in the
wide-open throttle position. At this point there is no longer be any control of the turbo boost
pressures. To control the maximum boost pressures the engine is equipped with a waste gate
and a waste gate control system. This system is used to prevent the turbocharger compressor
from surging and to prevent rapid fluctuation in engine speed during certain conditions: To
keep the turbocharger in the correct range of operation for the operating conditions, a
Turbocharger Control Module (TCM) is often incorporated into the engine's electronic
control system.

Engine Throttle Controllers
These controllers are attached to the engine governor or in some case ,to the engine throttle to
automatically change the engine speed according to the load conditions required at the driven
machine. This can be for simple operations like speeding up a welding machine when the
welder strikes an arc, or an engine speed can be controlled to maintain desired pressure in a
pump.

Engine Micro-Controllers
These are control panels that are capable of starting up unattended engines and monitoring
engine functions while doing so. These operations include: pre-lube operation, cranking
intervals, warm-up time and loading of the engine. All of these operations all automatically
executed. These systems are also capable of shutting the engine down in the sequence that is
not detrimental to the engine's integrity. This includes such things as cool-down times and
post-lube functions. These systems also perform normal monitoring of the engine while it is
in operation.

Documentation and Laboratory Reports.
Documentation and report analysis is an essential link in preventive maintenance programs.
Millwrights work with P.M. work orders, regular work orders, oil analysis reports, coolant
analysis reports and work history documentation. All of these documents are important in the
development of a preventive maintenance program that aids in the maintenance and repair of the engine (see the module on Maintenance Planning).




The monitoring system may consist of a field panel with analog gauges. This type of panel is
usually mounted close to the engine. From this panel the operator can start the engine and
monitor the gauges on the panel. This panel usually has a throttle and start and shutdown
switches. The gauges on the panel incorporate shutdown switches. For example, the
temperature gauge has a built-in switch, which will trip the engine if the temperature goes
above a certain limit. The oil pressure gauge will also have a trip, which shuts down the
engine on low oil pressure. An example of this type of panel is shown in Fig. 45.
The digital type of monitoring and control system has become very popular. Digital systems,
as shown in Fig. 46, monitor and control most engine functions. It has a microprocessor
based control module (ECM), which takes inputs from engine sensors. It controls all engine
functions such as engine speed, timing, boost pressure and exhaust gas recirculation. The
digital system may be connected to a field mounted operator interface panel 47, or a remote
panel in a control room. The operator is able to input some control variables such as engine
speed and load. Most functions are controlled by the microprocessor.



Shutdowns of the engine are also built into digital based systems. They are programmed to
shut the engine down if limits are exceeded. The shutdowns are connected to an alarm panel,
which makes the operator aware of the alarm condition that exists. The alarm must be cleared
before the engine will restart. The engine may also shutdown if the microprocessor fails.
Microprocessor problems can be difficult to troubleshoot, and repair involves replacing
electronic components.

Objective 12
Explain a typical start-up procedure for a large industrial diesel engine, plus the routine
monitoring requirements of a running engine & Start up procedure.

Basic Engine Ture-Up
Ture-Up
Tune-up procedures for engines are as varied as the type of engine that is to be tuned. Most of
the tune-up information here is for engines that operate on natural gas or gaseous fuels.
Specific tune-up information should be obtained from the engine's service ' manuals. Many
checks are performed during tune-up. Some checks are made more frequently than only at
tune-up time, but when the engine is stopped for a tune-up the engine systems can be checked
more carefully.

Oil and Coolant levels
Oil and coolant levels should be checked daily, but 30150 during tune-up. Tune-up is also a
time to change oil and filters as recommended.

Crankcase Breather
Check the crankcase breather to make sure that it is clean so that the engine crankcase
receives fresh air. The breather must have a filter; otherwise, dust can enter the engine and
contaminate the oil.

Fuel Strainers (If Applicable)
If the engine has fuel filters, strainers, or scrubbers they should be checked, drained or
changed regularly. This can include disassembly, cleaning, or washing the strainer elements.

Air Cleaners
Air cleaners can be checked or changed and the restriction indicator checked to see whether it
shows red (reset if red is showing). If are available, follow the directions attached to the
cleaner. If no directions are visible, examine the cleaner to determine whether it is an oil bath
type or a dry type. Oil bath cleaners have an oil reservoir that traps the dirt in the oil to form a
thick sludge in the bottom of the oil reservoir. Wipe or wash out such accumulations and
replenish the reservoir to the indicated level with clean engine oil of the correct viscosity. The
oil in the air cleaner should be changed at each engine oil change.
Many intake systems have an air restriction indicator device mounted in the piping from the
air filter to the intake manifold. This device serves as positive evidence that air filter service
is necessary.

Dry-type air cleaners can be changed or cleaned. To clean the dry type's elements, first use
low-pressure compressed air in the opposite direction of the normal airflow. This can be
followed with washing with a soap and water solution. Then, set the filter out to air dry. Do
not use compressed air to dry air cleaners. Always replace the element after three cleanings.

Cooling Systems and Thermostat Change
Thermostats seldom need replacement. They should be checked from time to time, and are
accessible by removing the thermostat housing at the forward end of the engine or cylinder
head.
Use clean water for an engine coolant with the proper inhibitors, or antifreeze solutions. This
ensures that the radiator and cooling passage accumulations are not excessive. The engine
benefits if the cooling system is cleaned of sludge and sediment about a year.

Valve Train Adjustment
Periodic valve clearance adjustments must be made on engines that have solid lifters. Check
the valve lash at every tune-up or as the manual suggests.
Most gaseous-fuelled engines have very high combustion temperatures (2538°C or4600°F)
compared to those of diesel or gasoline engines. The valves on gaseous-fuelled engines are
made of materials specifically designed for these applications. Industrial engines are also
subjected to long, continuous operation. Due to the heat and the long duration of operation
the valves and seats wear and cause a reduction in valve lash, which eventually leads to a
valve not being able to close completely.
Accurate valve clearance settings can prolong engine life and help engine performance.
Valves that are not accurately set can impair performance, and excessive clearances are
detrimental to cams and tappets. When clearances are too tight, timing is slightly changed and
the possibility of burned valves becomes much greater.
One very important consideration during valve adjustment is the accurate positioning of the
camshaft in relation to the valve being adjusted. Valve clearance must be set only when the
cam follower is on the base circle of the camshaft. This means that the cam follower must not
be on any part of the camshaft lobe.
The least confusing way to set valves is to start with number one cylinder at TDC firing and
then proceed in the ruing order. Using a six-cylinder engine as an example, the" order is 1-5-
3-6-2-4. Remember that the engine rues on all cylinders in two complete revolutions (720°).
This means that on a six-cylinder engine you can set the valves of another cylinder every
120°.
The best way to determine TDC firing is to slowly rotate the engine crankshaft until push
rods of the same cylinder can be rotate by hand after the exhaust valve closes.

Compression Testing
Engine compression should be checked when the spark plugs are out of the engine. Check the
compression of gas and gasoline engines, a standard, automotive-type compression tester
with a threaded adapter can be used.
Before checking compression, ensure that the engine has been warmed up to operation
temperature. Gas and gasoline engines must have the throttle held in the open position and
the ignition switch in the off position. Pay attention to the number of compression strokes
needed to obtain the highest pressure reading. The compression pressures the range from 130
psi to approximately 190 psi ( or consult the manual for that engine) Uneven compression or
pressures lower than normal call for further checking. Valve seat regrinding, piston ring
replacement, or other overhaul procedures may be required to correct the problem.

Troubleshooting and Failure Analysis
Some basic steps can be used to find engine problems. Before these steps can be used, you
should be very familiar with the basic operating principles of the engine and the engine
systems.
There are two areas of engine troubleshooting. The first is determining if the engine has the
basic requirements necessary for it to operate. The second is that the engine may operate, but
the mechanical state may need correction.
All engines have a few basic things that they need in order to run. These are: fuel, air,
compression, and a source of ignition. If one of these is removed the engine does not start.
You must be able to identify which of these essentials is missing

Troubleshooting
The most common errors in troubleshooting are:
• Not investigating operations records,
• Not using readily available information as a diagnostic tool, and
• Making arbitrary adjustments and not fixing the real trouble.
Troubleshooting often begins with random replacement of parts or by adjusting balance
valves on all the power cylinders, when only a few need adjustment in order to improve the
load carrying availability of the engine. If the real problem is not detected or fixed, other
parts of the engine can easily be overloaded to make up for the defect of a single item.

Basic Steps
Troubleshooting requires a complete understanding of how the particular engine works and
the resources available to diagnose the problem. Tables and charts can only give basic
direction as to where a problem might be and how to correct it. Additional repair work is
sometimes needed beyond what is recommended on the chart. Electronic diagnostic tools are
available to help in troubleshooting most modem engines. Still, common sense can go a long
way in solving some engine problems.

STARTING A DIESEL ENGINE
Before starting a diesel engine, special care should be taken to see that the fuel-injection
pump is primed and that it will deliver fuel oil to the cylinders with the first revolution of the
engine. Precautions should also be taken to ensure that all valves work freely in their guides.
If the valve stems should appear sticky a little clean kerosene applied with a brush will
usually free them.
All lubricators, mechanical and otherwise should be filled, the feed opened and the pumps
primed to ensure prompt delivery of the lubricating oil to all relative moving parts. In
circulation systems the level of oil in the main reservoir should be checked and where
independently driven circulating pumps are employed, they must be put into operation before
starting the engine. In some designs manually operated semi-rotary pumps are fitted to the
engine circulation system in order that oil can be manually fed to the bearings, etc. before the
engine actually starts up.
The engine manufacturers instructions with regard to the cooling system arrangements should
also receive detailed attention and any recommendations strictly observed. If air-cooling is
used, the coolant level in the radiator should be checked. When water-cooling is used,
cooling water flow to the cooler should be turned on.
A bypass switch or bypass button is usually provided to disable or override trips during the
start-up mode. For example, the oil pressure may not go above the low oil pressure trip
setting until the engine has started up. While starting the engine the bypass switch is turned to
the startup position or the bypass button is pushed in to bypass the trips. Once oil pressure is
above the trip setting, the bypass button may be released or the switch returned to the run
position.
If possible the diesel engine should be run with little or no load until normal operating
temperature has been reached. A cold diesel engine sounds rough or harsh and smoothes out
as the engine temperature increases. When the engine operating temperature has been
reached, the load can be applied slowly.
Once the engine is under load, it should be monitored until the operating variables have
stabilized. It should be monitored both physically, at the location of the engine, and remotely
by control room operators. Notes should be made of any problems and logged for
communication to operators on other shifts and for follow up action if maintenance is needed.

Objective 13
State the purpose and methods of engine preventive maintenance programs

Preventive Maintenance Programs
Preventive maintenance programs are only effective if they have the support and effect both
the Maintenance and Operations departments of the company. If support and effect are not
available, time, money and effort are wasted. Some problems with maintenance programs are
due to previous decisions, which may have resulted in the wrong type of size of machinery
being used (for example, machinery that is too small for the production expected).
• Check to see whether the engines and related equipment are properly sized or
designed to fit the application. If they are not, it is impossible to maintain the engine
and driven equipment.
• The quality of the engines and driven equipment could make them a maintenance
problem.
• If the company or operations policies do not allow downtime, then the maintenance is
going to have to be patch-and-fix on a rush basis.
The purpose of any good preventive maintenance program is to achieve maximum of line
availability of the engines at reasonable cost. Various types of programs are used.
• Catastrophic maintenance - repair or overhaul are performed after a failure.
• Progressive maintenance - repair or overhaul is performed as part of the complete fix,
such as fixing one or two cylinders at a time.
• Periodic maintenance and inspection for example - the engine parts are periodically
inspected and replaced as required.
• Planned maintenance and overhaul - overhauls are done based on equipment
experience. The overhauls are planned and scheduled well in advance of a noticed.
• Predictive maintenance programs - the engine is monitored on a regular bases and
work is performed when there are signs that a problem may be progress the point
where correction should take place. Some of this monitoring includes oil analysis,
coolant checks, and observing the operations charts, pressures and temperatures.
Planned maintenance and predictive maintenance programs are often considered to be most
economical and have the greatest impact on the productivity of the machinery involved.


Overhauls should be well-planned and, if a specialty company is hired to I work, the
company should be consulted to form a plan of action. If work is scheduled properly, with
carefully laid-out disassembly and the parts required projected, costs easily be cut. Wellplanned
overhauls result in decreased downtime.
Accurate troubleshooting is an important part of a good preventive maintenance program.
Many problems can be detected by reviewing properly maintained operating logs and
detecting trends in pressure, temperature and speed. If the data is kept in well-designed logs,
problems should be apparent early.
Some of the basic pressure devices that should be monitored are lube oil, jacket water, air
manifold and crankcase pressure. Additional recommended monitoring systems or alarm and
shutdown devices are engine overspeed and excessive vibration systems.

Some suggested inspections are:
• Check the load on the engine and the driven unit.
• Frequently check all the liquid levels.
• Listen for excessive noise.
• Feel for vibration.
• Check the engine for lube oil consumption.
• Regular tune-ups are recommended. This includes adjusting valve clearances,
servicing air and oil filters, changing sparkplugs and checking the timing.
• The rod and main bearings should be inspected every year of continuous operation.
• The cylinder head should be removed and reconditioned every two or three years of
continuous operation.

Oil Changes
Lubrication intervals should coincide with other preventive maintenance services. However,
under unusual conditions, intervals should be shortened if there is evidence of dirt, sludge or
breakdown of lubricant.
Engines operating with low oil temperatures (below 160°F or 71°C) can be expected to show
excessive sludging and wear. Engines operating with high oil temperatures (above 230°F or
110°C) may experience lacquering and ring sticking due to oil oxidation.
Multi-viscosity oils (IOW-30, for example) should be used only when cold starting
conditions make it absolutely necessary.

The dark appearance of the oil is not necessarily an indication that the oil should be changed.
The use of some types of oil, a dusty environment, marginal installation, internal engine
condition and/or operating the engine with malfunctioning carburetion or injection equipment
may require more frequent oil changes. Lubricating oil should be monitored with a good oil
analysis program.

Monitoring and Shutdown Devices
Monitoring temperatures and pressures and the need for alarms and shutdowns, cannot be
overlooked. You should monitor the lube oil temperature out of the engine as well as the lube
oil temperature into the engine. The lube oil system should always have a pressure indicator
and shutdown device on the lube oil header.
The crankcase breather system on some engines is intended to maintain a vacuum at all times.
The amount of vacuum that is recommended is 0 to 0.5 inches water column. On some
engines the pressure is set to between 0 and 1 inch negative.

The advantages of the crankcase vacuum are:
• It helps prevent lube oil leaks and
• It helps detect problems within the engine.
Whenever blow by around the piston rings and liner is experienced, the crankcase
immediately changes from a vacuum to a positive pressure. If the pressure becomes high, oil
can be forced past the gaskets mid seals, causing an increase in oil consumed The importance
of this cannot be overstated. Different equipment and devices are used adjust this pressure.
On some engines this adjustment can be as simple as a butterfly valve that can be rotated to a
position that maintains optimum crankcase pressure. The adjustment devices must be
adjusted when the engine is operating at normal engine Crankcase gas analysis also gives an
indication of excessive blow by.

Oil Consumption
Some customers refer to lube oil consumption in gallons per day. Most people think the
larger the number, the more oil consumed in a given period. But when expressed correctly,
the opposite is the case.
Most original engine manufacturers today publish a specific list of approved lube oil
Oil Analysis
The recommended period for engine lube oil changes is every 1000 hours.

Another purpose of the lube oil analysis program is to detect different wear rates with the
engine and other contaminants, such as ethylene glycol. For example, the present iron
indicates piston and/or liner wear; copper and brass are associated with bearing bushing wear;
silicone is associated with air inlet problems; and high acid or low pressure related to water
problems.
Oil analysis is a maintenance tool that should not be overlooked. Become associate
a reputable oil analysis firm and log the rate of change of all contaminants.

Oil Contamination
All engines are susceptibility to contamination from ethylene glycol, either due to 1 gasket or
through major failures. Ethylene glycol contamination in small amounts can seriously
damage engine parts. After contamination, a sludge forms throughout engine; liners become
glazed; rings stick and tri-metal bearings can be severely dangerous
A flushing procedure that uses butyl cellosolve is recommended to remove the ethylene
glycol contamination.
Pre-lube pump or motor driven pump needs to be sized to pressurize the entire system Then,
using a mixture of 50% butyl cellosolve and 50% ten weight engine oil, flushing system at a
temperature between 21°C and 66°C (70 and 150° F). Flush for approximately ½ hour,
barring the engine over slowly to allow fluid to work into the moving parts. The system
should then be completely drained and the filters change

Oil Samples
The purpose of taking oil samples is to establish the condition of the engine oil, to check for
contamination and determine whether the oil is breaking down. It is wise to take a sample of
new oil; this establishes a baseline, which is helpful when a used oil sample sent for analysis.
Special care must be taken while drawing the oil sample. Samples can be taken from the
crankcase, the sump Or reservoir drain. Always take oil samples from the same location on
the engine. Use the following guidelines for taking samples:
• Follow the manufacturer's reconunendations for oil sample intervals.
• The sample should be taken while the engine is at or near operating temperature
Always take samples prior to adding oil.
• Only use the containers supplied by the laboratory and ensure that the container are
not contaminated.
• Follow the laboratory's procedure for taking samples.
An analysis provide some of the following information:
• Viscosity,
• Fuel dilution,
• Coolant contamination,
• Water contamination,
• Spectrographic analysis and ferrographic (metallurgical) analysis results,
• Total base number,
• Total acid number and
• Oxidation levels.
The above results aid in deciding the oil change intervals.

Coolant Samples
Coolant analysis consists of three main activities:
• Using the recommended coolant from the engine and coolant manufacturer,
• Sending in samples as prescribed by the testing laboratory and
• Following up on the lab's recommendations and report directions in order to address
coolant deficiencies.
The steps for taking coolant samples are basically the same as those for taking oil samples.
Although cooling analysis is similar to oil analysis, there is one major difference: with
coolants there is an opportunity to add inhibitors to address any deficiency that is
encountered.



the course has been finished 
good luck

4-crankcase ventilation and induction systems(function, operation, inspection, and service) - automobile engineering



  
in the previous sections we had discuss :

- Classification of Internal Combustion Engines and Engine Components (Course)

- Internal Combustion Engines Components 2 (Course)

 3- Internal Combustion Engines cooling and lubrication system (Course)






 In This  section we will discuss :
-Describe the crankcase ventilation systems, function, operation, inspection, and
service.
-Describe the induction systems, functions, operation, inspection, and service
-Describe engine-starting devices/systems for diesel and gas engines.

 


 SECTION 4



Objective 8

Describe the crankcase ventilation systems, function, operation, inspection, and
service.



CRANKCASE VENTILATION

Function of the Crankcase Ventilation System

The crankcase ventilation system keeps the engine crankcase purged of blowby and
water

vapour. BIowby is burned and unburned gases that escape past the rings into the
crankcase.

The water comes from condensation or water vapour from incoming air and as a
product of

combustion. These gases and water together form corrosive acids and sludge in
the crankcase.


NOTE
The volume of the crankcase changes constantly as the pistons
move up and down, so the crankcase ventilation system has to "make up" air or breathe.
 

Operation of the Crankcase Ventilation System
The most common methods of crankcase ventilation are:

• Passive ventilation systems
A passive system usually has a breather on the valve cover, with a mesh filter
to let air into the engine and a vent tube along the side of the engine to allow crankcase
air to escape to the atmosphere. This system usually has some positive pressure in thecrankcase.


• Positive crankcase ventilation

Most industrial engines have a positive crankcase ventilation system. Positive ventilation systems can have either a positive pressure in the crankcase  (typical of automotive engines) or a vacuum in the crankcase. Both systems have breathers
for air to enter the crankcase, but the air is pulled out of the engine by a tube
attached from the crankcase to the intake manifold. On turbocharged engines with pressure in
the intake manifold, the line is connected before the turbo or, on some engines,
connected to a venturi set up in the exhaust system. The negative pressure positive
crankcase systems create a vacuum of 0 to 0.5 inches of water column in the crankcase. Changing the orifice size in the breather line sets the amount of vacuum created
in the crankcase. A vacuum in the crankcase helps prevent lube oil leaks, crankcase explosions and, since these engines are equipped with a crankcase manometer, provides early indication of engine problems.

Inspection and Service of the Crankcase Ventilation System
The breather on the crankcase ventilation system should be checked to make sure
it is present and not plugged. If it is not present, dirty air enters the crankcase and
contaminates the engine oil. Systems that have positive suction on the crankcase can have a problem with  overscavenging. This occurs when too much air is pulled through the system along with oil vapours, resulting in oil consumption. A breather assembly filled with a wire
mesh eliminates this 'pull-over' of oil and also an orifice limits the amount of air that passes
through the system. The crankcase ventilation system can be checked with a manometer for the
correct value. The manometer also indicates if there is too much blowby, which is caused
by leaking rings or scuffed liners.


Objective 9

Describe the induction systems, functions, operation, inspection, and service.


INDUCTION AND EXHAUST SYSTEMS

Function of the Induction System

The induction system must be able to supply clean air at the proper temperature
and Quantity to the engine for combustion.

• The induction system cleans the air so that it is free of abrasive particles
that can affect the life of the engine.

• The induction system ensures that a sufficient quantity of air is supplied for
the size of the engine.

• The air should be at the correct temperature to aid in combustion and engine efficiency.

• The air also aids in cooling the valves and other internal parts. This is
particularly important on turbo-charged engines.

• The inlet system must also silence the incoming air.

Industrial engines use a lot of air ! An inadequate volume of air for a given amount of fuel causes excessive fuel consumption and can lead to a loss in power. A typical
industrial engine can use approximately 4320000 cubic feet of air in one day. That is a lot of air
to clean. Clean air is important. Dirt in the air is the engine's worst enemy because it
is abrasive and prematurely wears the rings and liners. An engine without an air filter can be
ruined in a very short time. On industrial sites, the air may appear to be clean, but there is a
lot of dirt suspended in the air. Air temperature is also important. For maximum efficiency the best temperature is from 15ºC (60º P) to 32ºC (90º P). If the air is too hot the power drops off
approximately 1 % for every 10º C (l8º P) rise in temperature over 32º C (90º P). If the air is too
cold in winter, the low air temperature leads to a drop in compression temperature, which results in poorer fuel ignition and thermal shock to the engine.


Operation of the Induction System

Paris of the Induction System

The induction system is contains a pre-cleaner, an air cleaner and an intake
manifold and may have a turbo, blower, or a piston-type air pump.


Air Filters

Pre-cleaners are installed before the air cleaner to increase the service
intervals of the air cleaner and are usually installed in an area relatively free from dust.
Pre-cleaners remove larger particles of dirt or other foreign matter. Some pre-cleaners have a
spiral vaned drum that spins the air and forces the dirt out via centrifugal force. Dry air filters are the most common and have an efficiency of approximately 99%. The" density of paper used in the element controls the cleaning. As the element becomes dirty, the cleaning ability increases, but the flow through the element decreases. Dry  paper elements are versatile and are not messy to service.

Oil bath air cleaners have an efficiency of 95% to 98%. There are several
types, but most direct the air so that it has to make a sharp comer, at which point the air
encounters the oil. The dirt particles are caught in the oil. A mesh that is covered with oil traps
the remaining particles. Proper operation of the cleaner depends on maintaining the oil at the
correct level. It is also critical to use the correct viscosity and type of oil in the air
cleaner and that the correct size cleaner for the airflow of that engine be used; otherwise, the.
cleaning ability can be affected. An air cleaner that is too small for the application draws oil into
the intake. An air cleaner that is too large does not clean the air properly;


Spiral rotor air cleaners do not use an element; instead, they use the speed
of the air passing through a tube with a spiral inside. The air is spun by the spiral, throwing the
dirt particles outward and into a collector that is emptied by a venturi mechanism in the
exhaust stack. These systems can be used alone or in conjunction with dry cleaners as a
pre-cleaner.


Methods of Induction
Natural aspiration relies on atmospheric pressure to push air into the cylinders
when the piston moves downward. This is due to the fact that a slight vacuum is created
in the cylinder. If the cylinders are not sealing very well, the amount of air entering the
cylinder is affected. The speed of the engine also affects the amount of air entering the cylinder
because there is less time for atmospheric pressure to push the air in. Naturally aspirated
engines cannot reach 100% volumetric efficiency. Only four-stroke engines can be naturally aspirate?

Artificially aspirated engines use some mechanical means to push the air into
the cylinder.This can be a blower, turbocharger, or piston-type scavenge pump. With
artificial aspiration, the charge of air in the cylinder can be above atmospheric pressure.. If the
charge of air in the cylinder is above atmospheric pressure, it is referred to as supercharging or
boost pressure. The more boost the engine has, the more power the engine is capable of
producing. There are limits to the amount of supercharging because engine life can be threatened by too much boost. Two-stroke engines must be artificially aspirated; four-stroke engines can be artificially aspirated. Methods for moving the air are discussed later in the
module. Piston-type scavenging pumps (reciprocating blowers) are used on some very large
two stroke industrial engines. This is not the most effective way to move air into the
cylinder and the pump is often supplemented by a turbocharger. Very small two-stroke engines use the bottom of the piston and a sealed crankcase to push air into the cylinder.

Blowers are air pumps that are mechanically driven by the engine. They can be
belt or gear drive. The speed at which they are driven determines the boost given to the
engine. Blowers have a parasitic effect on the engine because of the amount of power required to drive the blower. There are two types of blowers:


• Lobed blowers (roots blowers), which are positive displacement units that are
used on engines. These blowers have two rotary members with two or three lobes. The
lobes are timed with gears to avoid contact. The air delivered is proportional to
engine speed and run at relatively low rotational speeds (2000 to 6000 rpm). These are mostly used on two-stroke industrial engines.

• Centrifugal blowers, which are non-positive displacement units that look like turbochargers except that they are mechanically driven by the crankshaft. These blowers use high velocity air to increase air pressure and have high rotational speeds (10 000 to 50 000 rpm). Their most common use is on large, stationary, two-stroke engines.

Turbochargers (turbo) are the most popular and effective method used to increase
the power on modern engines. Turbochargers are radial flow centrifugal compressors
driven by turbine wheels. The engine's exhaust gases drive the turbine wheel. There is no
mechanical link between the turbocharger and the engine. This may make it appear as if there are no parasitic

losses when using a turbocharger. This is only partially true; the turbocharger
causes back pressure in the exhaust system, leading to some pumping losses Turbo speed
is determined by the amount of fuel burned (exhaust produced); not by engine speed. Turbochargers are more efficient than blowers except that they do not start
turning until the engine is making exhaust. This makes it difficult to use a turbo on a two.
stroke engine. Twostroke engines that have turbochargers have mechanically driven blowers and a turbo, or have only a turbo with provision for jets of compressed air to star the turbo turning
for start-up and low speed operation. (More on turbochargers in turbocharger section of this
module).


Two-Stroke Scavenging
Supercharging should not be confused with scavenging. The scavenging process in
a two cycle engine is used to force out the spent exhaust gases and to replace them
with fresh air at approximately atmospheric pressure. The engine mechanically drives the
scavenging pump. The air density after cylinder scavenging is no greater than it would have been had atmospheric air pressure filled the cylinders. Scavenging pumps may be roots or
centrifugal blowers, piston-type pumps, or turbochargers.

Types of Scavenging
Loop flow scavenging occurs when the flow of the air into the cylinder and the
exhaust flow out of the cylinder come from the same side of the cylinder. This forms a loop
in the gas flow.

Uniflow scavenging is used on engines. The inlet and exhaust ports are at
opposite ends of the cylinder; thus, the airflow is from one end of the cylinder to the opposite.
This is a very affective scavenging arrangement.The crossflow scavenging arrangement has the exhaust ports on opposite sides of the cylinders. The flow of the gas is from one side (intake side) of the cylinder to the top and

back down to the opposite side (exhaust side) to the exhaust ports.




Inspection and Service of Induction Systems

Air Cleaner Service
For all filter types it is important that the ducting after filtration does not
leak. Check to ensure that the filter elements have sealed properly (some use rubber strips).
Leakage through the piping or past the air filter allows dirt into the engine and reduces engine
life considerably.


Air cleaner condition can be checked for restriction with several methods:
• Air cleaner service indicators are commonly used on intake manifolds. They
flag when restriction in the manifold reaches a predetermined amount.

• The most accurate method of measuring air cleaner restriction is using a water manometer.


Dry Air Cleaners
Dry or paper element filters can be checked visually by placing a light behind
the element and looking for the amount of light that comes through. The element can easily
be replaced. Dry elements can be cleaned by carefully using compressed air (blow from the
inside outward). Some paper elements can be washed and dried when they become too
dirty. The element should be inspected for holes or tears if it is to be reused. Never use
an air cleaner that has holes in the element.


Oil Bath Air Cleaners
Service oil-type filters by removing the oil cup, then cleaning and replacing
the oil to the correct level. Allow no more than ½ inch of sludge to accumulate before
servicing the filter.

(USE THE CORRECT VISCOSITY OIL. This is very critical in cold weather).


NOTE
Oil bath air cleaners should be the correct size for the engine. Failure to
use the correct size air cleaner results in several problems. If the cleaner is too small, oil
"pull over" into the engine can result. If the filter is too big for the engine, the engine
does not filter well because of the reduced air velocity.


Pre-Cleaner Service
Some pre-cleaners are serviced daily, depending on the dust conditions. Others
have a oneway rubber ejector valve in the canister to eject dirt and water. Most larger air
cleaners eject the dirt automatically with the aid of a venturi in the exhaust system. Check
pre-cleaners for damage; otherwise, they will be rendered useless.


Manometers
Manometers are valuable tools for checking air cleaner restriction, turbo boost,
and manifold pressure or vacuum. The V-tube manometer is a primary measuring device that indicates pressures or vacuums by the difference in the height of two columns of fluid. It is usually used for low-pressure applications. There are two types: water-filled and mercury-filled.


Water Manometers
Connect the manometer to the source of pressure or vacuum. When a pressure is
imposed, add the number of inches by which the water in one column of fluid travels
upwards to the amount the other column travels downwards to obtain the pressure (of vacuum)
reading.


Mercury Manometers
The height of a column of mercury is read differently than that of a column of
water. Mercury does not wet the inside surface of the tube; therefore, the top of the column
has a convex meniscus (shape). Water wets the surface and therefore has a concave meniscus. A mercury column is read by sighting horizontally between the top of the convex mercury
surface and the scale. A water manometer is read by sighting horizontally between the bottom
of the concave water surface and the scale. Should one column of fluid travel farther
than the fluid in the other column, due to minor variations in the inside diameter of the tube
or to the pressure imposed, the accuracy of the reading obtained is 1101 impaired. Refer
to the Conversion Chart to convert the manometer reading into other units of
measurement.

Intake Manifold Boost Pressure (Turbo Boost)
Use a mercury manometer to check pressure in the intake manifold of a
supercharged engine. The engine must be run at full load in order to check a turbocharged engine. The pressure ranges from 10 to 50 in. Hg.


Function of the Exhaust System
The exhaust system has an exhaust manifold, piping and a silencer. The exhaust
system must remove the exhaust with a minimum of restriction, good flow characteristics, and
adequate silencing.


Operation of the Exhaust System
Exhaust systems are tailored for the engine. Piping that is too large or too
small can affect the efficiency of the exhaust flow. The length of the piping can also affect the
exhaust flow. Connecting the exhaust systems of several engines causes condensation in the
cylinders of the engine that is not running. Silencers or mufflers should have a minimum
backpressure, but must reduce the noise from pulsations in the exhaust system. Some newer
engine installations are equipped with catalytic converters to comply with government
exhaust emission standards. Many natural gas engines have water-cooled exhaust manifolds. This is because of  the high exhaust temperatures experienced by the engines. Water-cooled exhaust manifolds help prevent warping and cracking of the manifold, but also reduce the radiant heat  to other parts of the engine and surroundings. .


Waste Gates and Dump Valves
If too much boost is produced in the intake the engine can generate more power
than the engine parts can withstand; therefore, the maximum pressure boost is regulated.
Waste gates are used on some turbochargers to regulate the turbo air pressure by dumping
the. exhaust gas to a bypass lireaches the turbine; thus, the turbine speed decreases and is not
able to compress as much air. Waste gates may have various controls, from very simple to sophisticate with multiple controls.'


Intercoolers and Aftercoolers
Intercoolers and aftercoolers cool the air between the turbocharger and the
cylinder. These units are heat exchangers placed between the supercharger (turbocharger) and the  engine. Some are located in the engine intake manifold (intercooler) or elsewhere (afrercooler), and they can use engine coolant or ambient air to absorb the heat from' incoming
compressed air from the supercharger. By cooling the air, the air's density is increased; thus,
more fuel can be added and a further power increase can be obtained from the same displacement  engine. Air at 32°C (90°F) compressed by a turbocharger to double atmospheric pressure reaches approximately 150°C (300°F). Aftercooling results in cooler and more air
entering the cylinder. This helps in cooling engine parts (valves and pistons), lowering
cylinder peak pressures, and lowering the exhaust temperature. The most common aftercoolers
are air-towater or air-to-air. Many larger engines have a separate cooling system and water pump for the aftercooler.


Objective 10

Describe engine-starting devices/systems for diesel and gas engines.



STARTING METHODS
In order to start an internal combustion engine it is necessary to rotate the
engine by some means. This rotation will allow a charge of air (diesel engine) or air-fuel
mixture (gasoline engine) to be drawn into the cylinders and compressed prior to firing. The
rotation will also cause certain auxiliaries to operate such as the fuel injection system in the
diesel or the carburetor and ignition system in the gasoline engine. Several different methods of rotating the engine may be employed. In the case of a very small engine, a hand turned crank may be used. With larger engines, the method usually used is an electric motor driven by a storage battery. Large diesel engines most commonly use compressed air, which is admitted into one or more cylinders to drive the engine pistons.


Electric Starters
An electric starter motor powered by a storage battery may start small engines
and even engines up to 1000 kW. The motor cranks the engine until ignition takes place.
The engine speed increases and disengages the starter motor gearing. The operator shuts off
power to the starting motor, when the engines fires up. An electric starter motor is shown in
Fig.41. The pinion drive gear connects it mechanically to the engine flywheel. The electric  motor is a dc type, enclosed to make it weatherproof.


Air Starting Systems
Some medium sized and most large diesel engines are started with compressed air.
Starting by compressed air takes one of two forms: the air might be directed to an air
motor to carry out cranking, or it might be led through a distributing device to the main power
cylinders of the diesel engine. This system requires a two or three-stage compressor to fill
the starting air receiver with air at a pressure of 2000 - 2500 kPa. The air receiver capacity
should be sufficient for twelve starts without recharging from the compressor. When air is to be fed to the main power cylinders, the air-distributing device  is operated by the camshaft and serves to direct the high-pressure air to each cylinder on its  power stroke. The air, usually at about 2100 kPa, is fed through air-starting valves fitted in the cylinder heads. The air admitted drives the engine in a manner similar to that of steam driving a steam engine.

The expansion of the starting air cools the cylinders and makes ignition
difficult. Therefore, only a few of the cylinders are used for starting. The engine is turned to a
specified starting position indicated on the flywheel. The engine must have timing valves to supply starting air through starting valves (see Fig.42) to the cylinders on their power strokes.


The engine should fire after the first full compression stroke and no more
starting air is supplied. A starting system using an air motor is shown in Fig.43. The air starting
system has its own tank, compressor and drying system. A push button valve activates flow of air to the starting motor via a relay valve. The air, which turns the starting, motor and is vented
to atmosphere. As the air is dry and has no lubrication qualities, lubricating oil is added to
the air motor. The air motor will turn over the diesel engine until it starts or until the air
supply runs out. The air motor system will turn the engine faster than an electric starter. This is an
advantage in building up the temperature for the diesel to start.


Hydraulic Starting Systems
The hydraulic starting system uses a hydraulic motor to turn over the diesel for
starting. This type of system is shown in Fig.44. The accumulator holds a quantity of oil under
high pressure, 10 000 to 20 000 kPa. To start the motor the oil flows from the
accumulator to the hydraulic motor, causing rotation. The low-pressure oil flows back to a
reservoir. The starter motor has a pinion, which turns the diesel engine flywheel. When
the diesel starts, the flow of oil is shut off and the pinion drive disengages. The engine driven
hydraulic pump restores the pressure in the accumulator. A hand pump is also supplied as a back up should the engine driven hydraulic pump fail.