materials 1
TRANSCRIPT
COURSE PREPARED BYM.JAYAPRASAD
MATERIALS, MANUFACTURING AND TESTING OF ENGINE
221076 MATERIALS, MANUFACTURING AND TESTING OF ENGINE L T P C 3 0 0 3
AIM: To know the engine materials, manufacturing methodology and testing methodology.OBJECTIVE: To provide knowledge on engine materials, manufacturing and testing of engine components.
UNIT I MATERIALS 7
Selection – types of Materials – Ferrous – Carbon and Low Alloy steels, High Alloy Steels, Cast Irons – Non Ferrous – Aluminium, Magnesium, Titanium, Copper and Nickel alloys.
UNIT II ENGINE COMPONENTS 15
Cylinder Block, Cylinder Head, Crankcase and Manifolds, Piston Assembly, Connecting Rod, Crankshaft, Camshaft And Valve Train - Production methods – Casting, Forging, Powder Metallurgy – Machining – Testing Methods.
UNIT III ENGINE AUXILIARIES 7Carburettors, fuel injection system components, radiators, fans, coolant pumps, ignition System.
UNIT IV COMPUTER INTEGRATED MANUFACTURING 7
Integration of CAD, CAM and CIM- Networking, CNC programming for machining ofEngine Components.
UNIT V QUALITY AND TESTING 9
TS 16949, B I S codes for testing. Instrumentation, computer aided engine testing, metrology for manufacturing Engine Components.
TEXT BOOKS : TOTAL: 45 PERIODS
1. Grover, M.P., CAD/CAM, Prentice Hall of India Ltd., 1985.2. Heldt, P.M., High speed internal combustion engines, Oxford & IBH Publishing Co., 1960.3. Judge, A.W., Testing of high speed internal combustion engines,
Chapman & Hall., 1960.
REFERENCE BOOKS:1. Richard, W., He ine Carl R. Loper Jr. and Philip, C., Rosentha l , Principles of Metal Casting, McGraw-Hill Book Co., 1980.2. IS: 1602 – 1960 Code for testing of variable speed internal Combustion engines for Automobile Purposes, 1966.3. SAE Handbook, 1994.4. P.Radhakrishnan and S.Subramaniyan, CAD/CAM/CIM, New Age
International (P) Limited, Publishers, 1997.5 .Mikett P.Groover, Automation, production Systems and Computer – Integrated Manufacturing Printice Hall of India Private Limited, 1999.
UNIT I MATERIALS
Low carbon steels
.Low carbon steel contains approximately 0.05–0.15% carbon and mild steel contains
0.16–0.29% carbon, therefore it is neither brittle nor ductile. Mild steel has a relatively
low tensile strength, but it is cheap and malleable; surface hardness can be increased
through carburizing. The density of mild steel is approximately 7.85 g/cm3 and the
Young's modulus is 210,000 MPa If low carbon steel is only stressed to some point
between the upper and lower yield point then the surface may develop Lüder bands.
Medium carbon steel
Approximately 0.30–0.59% carbon content. Balances ductility and strength and has good
wear resistance; used for large parts, forging and automotive components
Higher carbon steels
Higher carbon steels Carbon steels which can successfully undergo heat-treatment have
carbon content in the range of 0.30–1.70% by weight. Trace impurities of various other
elements can have a significant effect on the quality of the resulting steel. Trace amounts
of sulfur in particular make the steel red-short. Low alloy carbon steel, such as A36
grade, contains about 0.05% sulfur and melts around 1,426–1,538 °C (2,599–2,800 °F).
Manganese is often added to improve the hardenability of low carbon steels.
Ultra-high carbon steel
Approximately 1.0–2.0% carbon content. Steels that can be tempered to great hardness.
Used for special purposes like (non-industrial-purpose) knives, axles or punches. Most
steels with more than 1.2% carbon content are made using powder metallurgy. Note that
steel with carbon content above 2.0% is considered cast iron.
Alloy steel
Alloy steel is steel alloyed with a variety of elements in total amounts of between 1.0%
and 50% by weight to improve its mechanical properties. Alloy steels are classified into
two groups: low alloy steels and high alloy steels. The following are a range of improved
properties in alloy steels (as compared to carbon steels): strength, hardness, toughness,
wear resistance, hardenability, and hot hardness. In order to achieve some of these
improved properties the metal may require heat treating.
Common alloyants include manganese (the most-common one), nickel, chromium,
molybdenum, vanadium, silicon, and boron. Less common alloyants include aluminum,
cobalt, copper, cerium, niobium, titanium, tungsten, tin, and zirconium.
Some of these find uses in exotic and highly-demanding applications, such as in the
turbine blades of jet engines, in spacecraft, and in nuclear reactors. Because of the
ferromagnetic properties of iron, some steel alloys find important applications where their
responses to magnetism are very important, including in electric motors and in
transformers,
Cast iron
Cast iron usually refers to grey iron, but also identifies a large group of ferrous alloys,
which solidify with a eutectic. The colour of a fractured surface can be used to identify an
alloy. White cast iron is named after its white surface when fractured, due to its carbide
impurities which allow cracks to pass straight through. Grey cast iron is named after its
grey fractured surface, which occurs because the graphitic flakes deflect a passing crack
and initiate countless new cracks as the material rupture.
Carbon (C) and silicon (Si) are the main alloying elements, with the amount ranging from
2.1 to 4 wt% and 1 to 3 wt%, respectively. While this technically makes these base alloys
ternary Fe-C-Si alloys, the principle of cast iron solidification is understood from the
binary iron-carbon phase diagram. Since the compositions of most cast irons are around
the eutectic point of the iron-carbon system, the melting temperatures closely correlate,
usually ranging from 1,150 to 1,200 °C (2,102 to 2,192 °F), which is about 300 °C (572
°F) lower than the melting point of pure iron.
Cast iron tends to be brittle, except for malleable cast irons. With its relatively low
melting point, good fluidity, castability, excellent machinability, resistance to
deformation and wear resistance, cast irons have become an engineering material with a
wide range of applications and are used in pipes, machines and automotive industry parts,
such as cylinder heads (declining usage), cylinder blocks and gearbox cases (declining
usage). It is resistant to destruction and weakening by oxidisation (rust).
Grey cast iron
Grey cast iron is characterized by its graphitic microstructure, which causes fractures of
the material to have a grey appearance. It is the most commonly used cast iron and the
most widely use cast material based on weight. Most cast irons have a chemical
composition of 2.5 to 4.0% carbon, 1 to 3% silicon, and the remainder is iron. Grey cast
iron has less tensile strength and shock resistance than steel, however its compressive
strength is comparable to low and medium carbon steel.
White cast iron
With a lower silicon content and faster cooling, the carbon in white cast iron precipitates
out of the melt as the metastable phase cementite, Fe3C, rather than graphite. The
cementite which precipitates from the melt forms as relatively large particles, usually in a
eutectic mixture, where the other phase is austenite (which on cooling might transform to
martensite). These eutectic carbides are much too large to provide precipitation hardening
(as in some steels, where cementite precipitates might inhibit plastic deformation by
impeding the movement of dislocations through the ferrite matrix). Rather, they increase
the bulk hardness of the cast iron simply by virtue of their own very high hardness and
their substantial volume fraction, such that the bulk hardness can be approximated by a
rule of mixtures. In any case, they offer hardness at the expense of toughness. Since
carbide makes up a large fraction of the material, white cast iron could reasonably be
classified as a cermet. White iron is too brittle for use in many structural components, but
with good hardness and abrasion resistance and relatively low cost, it finds use in such
applications as the wear surfaces (impeller and volute) of slurry pumps, shell liners and
lifter bars in ball mills and autogenous grinding mills, balls and rings in coal pulverisers,
and the teeth of a backhoe's digging bucket (although cast medium-carbon martensitic
steel is more common for this application).
It is difficult to cool thick castings fast enough to solidify the melt as white cast iron all
the way through. However, rapid cooling can be used to solidify a shell of white cast
iron, after which the remainder cools more slowly to form a core of grey cast iron. The
resulting casting, called a chilled casting, has the benefits of a hard surface and a
somewhat tougher interior.
High-chromium white iron alloys allow massive castings (for example, a 10-tonne
impeller) to be sand cast, i.e., a high cooling rate is not required, as well as providing
impressive abrasion resistance.[citation needed]
Malleable cast iron
Malleable iron starts as a white iron casting that is then heat treated at about 900 °C
(1,650 °F). Graphite separates out much more slowly in this case, so that surface tension
has time to form it into spheroidal particles rather than flakes. Due to their lower aspect
ratio, spheroids are relatively short and far from one another, and have a lower cross
section vis-a-vis a propagating crack or phonon. They also have blunt boundaries, as
opposed to flakes, which alleviates the stress concentration problems faced by grey cast
iron. In general, the properties of malleable cast iron are more like mild steel. There is a
limit to how large a part can be cast in malleable iron, since it is made from white cast
iron.
Non Ferrous
Aluminium is a soft, durable, lightweight, ductile and malleable metal with appearance
ranging from silvery to dull gray, depending on the surface roughness. Aluminium is
nonmagnetic and non sparking. It is also insoluble in alcohol, though it can be soluble in
water in certain forms. The yield strength of pure aluminium is 7–11 MPa, while
aluminium alloys have yield strengths ranging from 200 MPa to 600 MPa. Aluminium
has about one-third the density and stiffness of steel. It is easily machined, cast, drawn
and extruded.
Corrosion resistance can be excellent due to a thin surface layer of aluminium oxide that
forms when the metal is exposed to air, effectively preventing further oxidation. The
strongest aluminium alloys are less corrosion resistant due to galvanic reactions with
alloyed copper. This corrosion resistance is also often greatly reduced when many
aqueous salts are present, particularly in the presence of dissimilar metals.
Aluminium atoms are arranged in a face-centered cubic (FCC) structure. Aluminium has
stacking-fault energy of approximately 200 mJ/m2.
Aluminium is one of the few metals that retain full silvery reflectance in finely powdered
form, making it an important component of silver paints. Aluminium mirror finish has the
highest reflectance of any metal in the 200–400 nm (UV) and the 3,000–10,000 nm (far
IR) regions; in the 400–700 nm visible range it is slightly outperformed by tin and silver
and in the 700–3000 (near IR) by silver, gold, and copper.
Applications
Transportation (automobiles, aircraft, trucks, railway cars, marine vessels, bicycles etc.)
as sheet, tube, castings etc. Packaging (cans, foil, etc.)
Construction (windows, doors, siding, building wire, etc.)
A wide range of household items, from cooking utensils to baseball bats, watches.
Street lighting poles, sailing ship masts, walking poles etc.
Outer shells of consumer electronics, also cases for equipment e.g. photographic
equipment.
Electrical transmission lines for power distribution
MKM steel and Alnico magnets
Super purity aluminium (SPA, 99.980% to 99.999% Al), used in electronics and CDs.
Heat sinks for electronic appliances such as transistors and CPUs.
Substrate material of metal-core copper clad laminates used in high brightness LED
lighting.
Powdered aluminium is used in paint, and in pyrotechnics such as solid rocket fuels and
thermite. Aluminium can be reacted with hydrochloric acid to form hydrogen gas.
A variety of countries, including France, Italy, Poland, Finland, Romania, Israel, and the
former Yugoslavia, have issued coins struck in aluminium or aluminium-copper alloys.
Some guitar models sports aluminium diamond plates on the surface of the instruments,
usually either chrome or black. Kramer Guitars and Travis Bean are both known for
having produced guitars with necks made of aluminium, which gives the instrument a
very distinct sound.
Magnesium
Physical and chemical properties Elemental magnesium is a fairly strong, silvery-white,
light-weight metal (two thirds the density of aluminium). It tarnishes slightly when
exposed to air, although unlike the alkali metals, storage in an oxygen-free environment
is unnecessary because magnesium is protected by a thin layer of oxide that is fairly
impermeable and hard to remove. Like its lower periodic table group neighbor calcium,
magnesium reacts with water at room temperature, though it reacts much more slowly
than calcium. When it is submerged in water, hydrogen bubbles will almost unnoticeably
begin to form on the surface of the metal, though if powdered it will react much more
rapidly. The reaction will occur faster with higher temperatures (see precautions).
Magnesium also reacts exothermically with most acids, such as hydrochloric acid (HCl).
As with aluminium, zinc and many other metals, the reaction with hydrochloric acid
produces the chloride of the metal and releases hydrogen gas.
Magnesium compounds are typically white crystals. Most are soluble in water, providing
the sour-tasting magnesium ion Mg2+. Small amounts of dissolved magnesium ion
contribute to the tartness and taste of natural waters. Magnesium ion in large amounts is
an ionic laxative, and magnesium sulfate (common name: Epsom salt) is sometimes used
for this purpose. So-called "milk of magnesia" is a water suspension of one of the few
insoluble magnesium compounds, magnesium hydroxide. The undissolved particles give
rise to its appearance and name. Milk of magnesia is a mild base commonly used as an
antacid, which has some laxative side effect
Magnesium Applications
Niche and illustrative uses of magnesium compounds Magnesium hydroxide is used in
milk of magnesia, its chloride, oxide, gluconate, malate, orotate and citrate used as oral
magnesium supplements, and its sulfate (Epsom salts) for various purposes in medicine,
and elsewhere. Oral magnesium supplements have been claimed to be therapeutic for
some individuals who suffer from Restless Leg Syndrome (RLS).
Magnesium borate, magnesium salicylate and magnesium sulfate are used as antiseptics.
Magnesium bromide is used as a mild sedative (this action is due to the bromide, not the
magnesium).
Magnesium carbonate (MgCO3) powder is also used by athletes, such as gymnasts and
weightlifters, to improve the grip on objects – the apparatus or lifting bar.
Magnesium stearate is a slightly flammable white powder with lubricating properties. In
pharmaceutical technology it is used in the manufacturing of tablets, to prevent the tablets
from sticking to the equipment during the tablet compression process (i.e., when the
tablet's substance is pressed into tablet form).
Magnesium sulfite is used in the manufacture of paper (sulfite process).
Magnesium phosphate is used to fireproof wood for construction.
Magnesium hexafluorosilicate is used in mothproofing of textiles.
Titanium
A metallic element, titanium is recognized for its high strength-to-weight ratio. It is a
strong metal with low density that is quite ductile (especially in an oxygen-free
environment), lustrous, and metallic-white in color. The relatively high melting point
(more than 1,650 °C or 3,000 °F) makes it useful as a refractory metal. It is paramagnetic
and has fairly low electrical and thermal conductivity.
It is fairly hard (although not as hard as some grades of heat-treated steel), non-magnetic
and a poor conductor of heat and electricity. Machining requires precautions, as the
material will soften and gall if sharp tools and proper cooling methods are not used. Like
those made from steel, titanium structures have a fatigue limits which guarantees
longevity in some applications. Titanium alloys specific stiffnesses are also usually not as
good as other materials such as aluminium alloys and carbon fiber, so it is used less for
structures which require high rigidity.
The metal is a dimorphic allotrope whose hexagonal alpha form changes into a body-
centered cubic (lattice) β form at 882 °C (1,620 °F). The specific heat of the alpha form
increases dramatically as it is heated to this transition temperature but then falls and
remains fairly constant for the β form regardless of temperature. Similar to zirconium and
hafnium, an additional omega phase exists, which is thermodynamically stable at high
pressures, but is metastable at ambient pressures. This phase is usually hexagonal (ideal)
or trigonal (distorted) and can be viewed as being due to a soft longitudinal acoustic
phonon of the β phase causing collapse of (111) planes of atoms.
Applications
Pigments, additives and coatings
Aerospace and marine
Industrial
Consumer and architectural
Medical Orthopedic implants
Piercing
Copper
Occupies the same family of the periodic table as silver and gold, since they each have
one s-orbital electron on top of a filled electron shell which forms metallic bonds. Like
silver and gold, copper is easily worked, being both ductile and malleable. The ease with
which it can be drawn into wire makes it useful for electrical work as does its excellent
electrical conductivity. Copper is normally supplied, as with nearly all metals for
industrial and commercial use, in a fine grained polycrystalline form. Polycrystalline
metals have greater strength than monocrystalline forms, and the difference is greater for
smaller grain (crystal) sizes.
In direct mechanical contact with metals of different electropotential (for example, a
copper pipe joined to an iron pipe), especially in the presence of moisture, as the
completion of an electrical circuit (for instance through the common ground) will cause
the juncture to act as an electrochemical cell (like a single cell of a battery). The weak
electrical currents themselves are harmless but the electrochemical reaction will cause the
conversion of the iron to other compounds, eventually destroying the functionality of the
union.
Copper does not react with water, but it slowly reacts with atmospheric oxygen forming a
layer of brown-black copper oxide. In contrast to the oxidation of iron by wet air, this
oxide layer stops the further, bulk corrosion. A green layer of copper carbonate, called
verdigris, can often be seen on old copper constructions, such as the Statue of Liberty.
Copper reacts with hydrogen sulfide- and sulfide-containing solutions, forming various
copper sulfides on its surface. In sulfide-containing solutions, copper is less noble than
hydrogen and will corrode. This is observed in everyday life when copper metal surfaces
tarnish after exposure to air containing sulfur compounds.
Copper is slowly dissolved in oxygen-containing ammonia solutions because ammonia
forms water-soluble complexes with copper. Copper reacts with a combination of oxygen
and hydrochloric acid to form a series of copper chlorides.
Copper reacts with an acidified mixture of hydrogen peroxide to form the corresponding
copper salt:
Uses
Electronics and related devices
Architecture and industry
Biomedical applications
Aquaculture applications
Nickel
Category: Nickel alloys
Alnico (aluminium, cobalt; used in magnets)
Alumel (nickel, manganese, aluminium, silicon)
Chromel (chromium)
Cupronickel (bronze, copper)
Ferronickel (nickel)
German silver (copper, zinc)
Hastelloy (molybdenum, chromium, sometimes tungsten)
Inconel (chromium, iron)
Monel metal (copper, iron, manganese)
Nichrome (chromium)
Nicrosil (chromium, silicon, magnesium)
Nisil (silicon)
Nitinol (titanium, shape memory alloy)
Soft magnetic alloys
Mu-metal (iron)
Nickel is a silvery-white metal with a slight golden tinge that takes a high polish. It is one
of only four elements that are magnetic at or near room temperature. Its Curie
temperature is 355 °C. That is, nickel is non-magnetic above this temperature. The unit
cell of nickel is a face centered cube with the lattice parameter of 0.352 nm giving an
atomic radius of 0.124 nm. Nickel belongs to the transition metals and is hard and ductile.
UNIT II ENGINE
Cylinder block is an integrated structure comprising the cylinder(s) of a reciprocating
engine and often some or all of their associated surrounding structures (coolant passages,
intake and exhaust passages and ports, and crankcase). The term engine block is often
used synonymously with "cylinder block"
In the basic terms of machine elements, the various main parts of an engine (such as
cylinder(s), cylinder head(s), coolant passages, intake and exhaust passages, and
crankcase) are conceptually distinct, and these concepts can all be instantiated as discrete
pieces that are bolted together. Such construction was very widespread in the early
decades of the commercialization of internal combustion engines (1880s to 1920s), and it
is still sometimes used in certain applications where it remains advantageous (especially
very large engines, but also some small engines). However, it is no longer the normal
way of building most petrol engines and diesel engines, because for any given engine
configuration, there are more efficient ways of designing for manufacture (and also for
maintenance and repair). These generally involve integrating multiple machine elements
into one discrete part, and doing the making (such as casting, stamping, and machining)
for multiple elements in one setup with one machine coordinate system (of a machine
tool or other piece of manufacturing machinery). This yields lower unit cost of
production (and/or maintenance and repair).
Today most engines for cars, trucks, buses, tractors, and so on are built with fairly highly
integrated design, so the words "monobloc" and "en bloc" are seldom used in describing
them; such construction is often implicit. Thus "engine block", "cylinder block", or
simply "block" are the terms likely to be heard in the garage or on the street.
Cylinder Crown
In an internal combustion engine, the cylinder head (often informally abbreviated to just
head) sits above the cylinders on top of the cylinder block. It consists of a platform
containing the poppet valves, spark plugs and usually part of the combustion chamber. In
a flathead engine, the mechanical parts of the valve train are all contained within the
block, and the head is essentially a flat plate of metal bolted to the top of the cylinder
bank with a head gasket in between; this simplicity leads to ease of manufacture and
repair, and accounts for the flathead engine's early success in production automobiles and
continued success in small engines, such as lawnmowers. This design, however, requires
the incoming air to flow through a convoluted path, which limits the ability of the engine
to perform at higher revolutions per minute (rpm), leading to the adoption of the
overhead valve (OHV) head design, and the subsequent overhead camshaft (OHC)
design.
Cylinder Crankcase
In an internal combustion engine of the reciprocating type, the crankcase is the housing
for the crankshaft. The enclosure forms the largest cavity in the engine and is located
below the cylinder(s), which in a multicylinder engine are usually integrated into one or
several cylinder blocks. Crankcases have often been discrete parts, but more often they
are integral with the cylinder bank(s), forming an engine block. Nevertheless, the area
around the crankshaft is still usually called the crankcase. Crankcases and other basic
engine structural components (e.g., cylinders, cylinder blocks, cylinder heads, and
integrated combinations thereof) are typically made of cast iron or cast aluminium via
sand casting. Today the foundry processes are usually highly automated, with a few
skilled workers to manage the casting of thousands of parts.
A crankcase often has an opening in the bottom to which an oil pan is attached with a
gasket bolted joint. Some crankcase designs fully surround the crank's main bearing
journals, whereas many others form only one half, with a bearing cap forming the other.
Some crankcase areas require no structural strength from the oil pan itself (in which case
the oil pan is typically stamped from sheet steel), whereas other crankcase designs do (in
which case the oil pan is a casting in its own right). Both the crankcase and any rigid cast
oil pan often have reinforcing ribs cast into them, as well as bosses which are drilled and
tapped to receive mounting screws/bolts for various other engine parts.
Besides protecting the crankshaft and connecting rods from foreign objects, the crankcase
serves other functions, depending on engine type. These include keeping the motor oil
contained, usually hermetically or nearly hermetically (and in the hermetic variety,
allowing the oil to be pressurized); providing the rigid structure with which to join the
engine to the transmission; and in some cases, even constituting part of the frame of the
vehicle (such as in many farm tractors).
Cylinder Manifold
Manifolds are used to connect two or more cylinders of gas together increasing the
supply volume available to provide a continuous flow when one cylinder is not sufficient
and a tube trailer or other bulk supply is not practical. Manifolds are also used when a
single cylinder of gas is not capable of supplying the required flow rate required by a
process.
Piston Assembly
The main parts of a piston are:
1 The top, which may also called the Head or Crown .
2 The Ring belt.
3 The Pin bosses.
4 The Skirt.
The top is part of the Combustion chamber The top may be flat , or a combustion
chamber may be cut into the top of the piston, the top may be raised or have a bowl cut
into it. Soot contamination of the lubricating oil in Diesel engines is reduced when the
combustion chamber is located in the piston, as opposed to the Cylinder head .
The piston skirt, which wraps around the lower part of the piston, distributes the side
loads and prevents the piston from rocking in the cylinder . long pistons rock less than
short ones and are used in diesel engine to reduce the number of required compression
rings . The pin boss supports the piston pin and transmits the force of combustion to the
pin. it is one of the most highly loaded areas of the piston .The piston pin is usually
hollow to reduce it's weight. The piston iS fitted with rings which ride in grooves cut in
the piston head to seal against gas leakage and control oil flow.
Piston Assembly
Pressure die casted, gravity die casted, shell moulded piston assembly are made out of
aluminium alloys, graded closed grained cast iron. Piston rings are individually
centrifugally casted out of high grade cast iron materials. Models available off shelf.
Packing/Piston Rings
We manufacture Carbon Packing Rings which are used in steam, Turbine, Water
Turbine, gas Turbine for different type of industries like Sugar, Cement, Textiles, Power
Plant and Electricity Board etc. These packing rings are of various types and size used in
turbine of various kind also the piston Rings which are also used in Compressors not only
as the Piston Rod Packing but also as the components of Pistons, Piston Rings and Guide
Rings. Carbon glands are used in the sealing of liquids and gases, restricting leakage to a
minimum. Carbon gland rings are provides an economical simple and effective seal on
impulse turbines, water turbines, steam turbines, gas turbines, low pressure fans and
blowers.
Piston Assemblies
In-house Manufacturing, Supplied with Piston Pin
Range: Over 1000 types
Material: Available in LM13, LM17 and LM21 material.
Type: Normal type, Ring Carrier type, Oil cooling gallery type, All types of coatings also
available.
Size Range: 60 mm to 175 bore size
Manufacturing Process: Automatic Die casting, T9 Heat Treated
Machining: On CNC and SPM
Installed Capacity: 25000 per month
Sample Development: 8 weeks, No tooling costs charged for order above 300 Pieces
Product Quality: OEM and after market
Connecting rod
In a reciprocating piston engine, the connecting rod or conrod connects the piston to the
crank or crankshaft. Together with the crank, they form a simple mechanism that
converts linear motion into rotating motion.
Connecting rods may also convert rotating motion into linear motion. Historically, before
the development of engines, they were first used in this way.
As a connecting rod is rigid, it may transmit either a push or a pull and so the rod may
rotate the crank through both halves of a revolution, i.e. piston pushing and piston
pulling. Earlier mechanisms, such as chains, could only pull. In a few two-stroke engines,
the connecting rod is only required to push.
Today, connecting rods are best known through their use in internal combustion piston
engines, such as car engines. These are of a distinctly different design from earlier forms
of connecting rods, used in steam engines and steam locomotives
While the two competing forging processes are similar, there are a number of subtle
differences between the two. The forged steel rod is fabricated by starting with a wrought
steel billet, heating the billet and forging it in the material’s plastic temperature range,
fracturing or cutting the rod cap end, and then machining portions of the product to
realize the final dimensional characteristics of the component.
The powder forged (PF) rod is: fabricated by consolidating metal powders into a perform
that is sintered, reheated to forging temperature (or in some cases forged subsequently to
sintering), fully densified by forging to final shape, fracturing of the rod cap end, and
then machined (minimally) to final dimensions.
A new steel, C-70, has been introduced from Europe as a crackable forging steel.
Alloying elements in the material enable hardening of forged connecting rods when they
undergo controlled cooling after forging. This material fractures in a fashion similar to
powder forged materials.
Crankshaft
The crankshaft, sometimes casually abbreviated to crank, is the part of an engine which
translates reciprocating linear piston motion into rotation. To convert the reciprocating
motion into rotation, the crankshaft has "crank throws" or "crankpins", additional bearing
surfaces whose axis is offset from that of the crank, to which the "big ends" of the
connecting rods from each cylinder attach.
It typically connects to a flywheel, to reduce the pulsation characteristic of the four-stroke
cycle, and sometimes a torsional or vibrational damper at the opposite end, to reduce the
torsion vibrations often caused along the length of the crankshaft by the cylinders farthest
from the output end acting on the torsional elasticity.
Crankshafts materials should be readily shaped, machined and heat-treated, and have
adequate strength, toughness, hardness, and high fatigue strength. The crankshaft are
manufactured from steel either by forging or casting. The main bearing and connecting
rod bearing liners are made of babbitt, a tin and lead alloy. Forged crankshafts are
stronger than the cast crankshafts, but are more expensive. Forged crankshafts are made
from SAE 1045 or similar type steel. Forging makes a very dense, tough shaft with a
grain running parallel to the principal stress direction. Crankshafts are cast in steel,
modular iron or malleable iron. The major advantage of the casting process is that
crankshaft material and machining costs are reduced because the crankshaft may be made
close to the required shape and size including counterweights. Cast crankshafts can
handle loads from all directions as the metal grain structure is uniform and random
throughout. Counterweights on cast crankshafts are slightly larger than counterweights on
forged crankshafts because the cast metal is less dense and therefore somewhat lighter.
Crankshaft Materials
Manganese-molybdenum Steel
1%-Chromium-molybdenum Steel
2.5%-Nickel-chromium-molybdenum Steel
3%-Chromium-molybdenum or 1.5%-Chromium-aluminium-modybdenum Steel.
Nodular Cast Irons
1. HARDENABLE IRON
This is Grade 17 cast iron with an addition of 1% chrome to create 5 to 7% free carbide.
After casting, the material is flame/or induction hardened, to give a Rockwell hardness of
52 to 56 on the C Scale. This material was developed in the 1930’s in America as a low-
cost replacement for steel camshafts and is mainly suited in applications where there is an
excess of oil, i.e., camshafts that run in the engine block and that are splash-fed from the
sump. (This is the material that the Ford OHC camshafts were manufactured from).
It is not the most suitable material for performance camshafts in OHC engines. As a
company, we only use this material for performance camshafts if the camshaft is splash-
fed in the sump.
2. SPHEROIDAL GRAPHITE CAST IRON KNOWN AS SG IRONA material giving similar characteristics to hardenable. Its failing as a camshaft material
is hardness in its cast form, i.e., Rockwell 5, which tends to scuff bearings in adverse
conditions. The material will heat treat to 52 to 58 RockwellC. This material was used by
Fiat in the 1980’s.
3. CHILLED CHROME CAST IRON
Chilled iron is Grade 17 cast iron with 1% chrome. When the camshaft is cast in the
foundry, machined steel moulds the shape of the cam lobe are incorporated in the mould.
When the iron is poured, it hardens off very quickly (known as chilling), causing the cam
lobe material to form a matrix of carbide (this material will cut glass) on the cam lobe.
This material is exceedingly scuff-resistant and is the only material for producing
quantity OHC performance camshafts.
Valve train
Term used to describe the mechanisms and parts which control the operation of the
valves. A traditional reciprocating internal combustion engine uses valves to control air
and fuel flow into and out of the cylinders, facilitating combustion.
Production Methods - Castings
Anchor Bronze & Metals Continuous Cast bronze is produced in stationary mold
continuous casting machines. All of the melting is done via electric induction crucible
furnaces. Melting occurs continuously, throughout the course of a production run.
Molten metal is poured into a crucible tundish furnace having a controlled atmosphere
(A) The tundish furnace maintains a large reservoir (B) of molten metal at a controlled
temperature above a water-cooled graphite die (C). Any dross entering the tundish
furnace quickly floats to the top of the metal bath where it is removed.
Metal enters the freezing zone of the die (D) at a temperature in sufficient excess of the
liquidus to assure that any shrinkage pores in prior cast material are filled. This is
accomplished in a fraction of a second before rapid freezing begins. Severe segregation
of alloying elements is thereby avoided. Special patented techniques further reduce
segregation and greatly improve casting strength by generating a fine grain structure in
the casting.
The newly frozen layer of metal shrinks rapidly away from the graphite die and is
withdrawn from the die by a set of electrically driven pinch rolls.
As the newly solidified portion of the casting leaves the freezing zone, the die is gravity
filled (E) with molten metal from the tundish. The solidification process begins again.
When the casting has attained the desired length, it is cut off with a flying saw positioned
below the pinch rolls. This process is used for production of intricate inside diameter
and/or outside diameter shapes. The vertical casting process is preferred for the
production of precision tubing. Tube concentricity of vertically cast product surpasses
that produced by all other metal working processes.
Advantages and disadvantages
Forging is a manufacturing process involving the shaping of metal using localized
compressive forces. Forging is often classified according to the temperature at which it is
performed: '"cold," "warm," or "hot" forging. Forged parts can range in weight from less
than a kilogram to 580 metric tons Forged parts usually require further processing to
achieve a finished part.
Forging can produce a piece that is stronger than an equivalent cast or machined part. As
the metal is shaped during the forging process, its internal grain deforms to follow the
general shape of the part. As a result, the grain is continuous throughout the part, giving
rise to a piece with improved strength characteristics.
Some metals may be forged cold, however iron and steel are almost always hot forged.
Hot forging prevents the work hardening that would result from cold forging, which
would increase the difficulty of performing secondary machining operations on the piece.
Also, while work hardening may be desirable in some circumstances, other methods of
hardening the piece, such as heat treating, are generally more economical and more
controllable. Alloys that are amenable to precipitation hardening, such as most
aluminium alloys and titanium, can be hot forged, followed by hardening
Production forging involves significant capital expenditure for machinery, tooling,
facilities and personnel. In the case of hot forging, a high temperature furnace (sometimes
referred to as the forge) will be required to heat ingots or billets. Owing to the
massiveness of large forging hammers and presses and the parts they can produce, as well
as the dangers inherent in working with hot metal, a special building is frequently
required to house the operation. In the case of drop forging operations, provisions must
be made to absorb the shock and vibration generated by the hammer. Most forging
operations will require the use of metal-forming dies, which must be precisely machined
and carefully heat treated to correctly shape the workpiece, as well as to withstand the
tremendous forces involved.
Drop forging Drop forging is a forging process where a hammer is raised up and then
"dropped" onto the workpiece to deform it according to the shape of the die. There are
two types of drop forging: open-die drop forging and closed-die drop forging. As the
names imply, the difference is in the shape of the die, with the former not fully enclosing
the workpiece, while the latter does
Press forging Press forging works by slowly applying a continuous pressure or force,
which differs from the near-instantaneous impact of drop-hammer forging. The amount
of time the dies are in contact with the workpiece is measured in seconds (as compared to
the milliseconds of drop-hammer forges). The press forging operation can be done either
cold or hot.
The main advantage of press forging, as compared to drop-hammer forging, is its ability
to deform the complete workpiece. Drop-hammer forging usually only deforms the
surfaces of the workpiece in contact with the hammer and anvil; the interior of the
workpiece will stay relatively undeformed. Another advantage to the process includes the
knowledge of the new part's strain rate. We specifically know what kind of strain can be
put on the part, because the compression rate of the press forging operation is controlled.
There are a few disadvantages to this process, most stemming from the workpiece being
in contact with the dies for such an extended period of time. The operation is a time
consuming process due to the amount of steps and how long each of them take. The
workpiece will cool faster because the dies are in contact with workpiece; the dies
facilitate drastically more heat transfer than the surrounding atmosphere. As the
workpiece cools it becomes stronger and less ductile, which may induce cracking if
deformation continues. Therefore heated dies are usually used to reduce heat loss,
promote surface flow, and enable the production of finer details and closer tolerances.
The workpiece may also need to be reheated. When done in high productivity, press
forging is more economical than hammer forging. The operation also creates closer
tolerances. In hammer forging a lot of the work is absorbed by the machinery, when in
press forging, the greater percentage of work is used in the work piece. Another
advantage is that the operation can be used to create any size part because there is no
limit to the size of the press forging machine. New press forging techniques have been
able to create a higher degree of mechanical and orientation integrity. By the constraint of
oxidation to the outer most layers of the part material, reduced levels of micro cracking
take place in the finished part.
Press forging can be used to perform all types of forging, including open-die and
impression-die forging. Impression-die press forging usually requires less draft than drop
forging and has better dimensional accuracy. Also, press forgings can often be done in
one closing of the dies, allowing for easy automation
Upset forging Upset forging increases the diameter of the workpiece by compressing its
length. Based on number of pieces produced this is the most widely used forging process.
A few examples of common parts produced using the upset forging process are engine
valves, couplings, bolts, screws, and other fasteners.
Upset forging is usually done in special high speed machines called crank presses, but
upsetting can also be done in a vertical crank press or a hydraulic press. The machines are
usually set up to work in the horizontal plane, to facilitate the quick exchange of work
pieces from one station to the next. The initial workpiece is usually wire or rod, but some
machines can accept bars up to 25 cm (9.8 in) in diameter and a capacity of over 1000
tons. The standard upsetting machine employs split dies that contain multiple cavities.
The dies open enough to allow the workpiece to move from one cavity to the next; the
dies then close and the heading tool, or ram, then moves longitudinally against the bar,
upsetting it into the cavity. If all of the cavities are utilized on every cycle then a finished
part will be produced with every cycle, which is why this process is ideal for mass
production.
The following three rules must be followed when designing parts to be upset forged:
The length of unsupported metal that can be upset in one blow without injurious buckling
should be limited to three times the diameter of the bar.
Lengths of stock greater than three times the diameter may be upset successfully
provided that the diameter of the upset is not more than 1.5 times the diameter of the
stock.
In an upset requiring stock length greater than three times the diameter of the stock, and
where the diameter of the cavity is not more than 1.5 times the diameter of the stock, the
length of unsupported metal beyond the face of the die must not exceed the diameter of
the bar.
The process starts by heating up the bar to 1,200 to 1,300 °C (2,192 to 2,372 °F) in less
than 60 seconds using high power induction coils. It is then descaled with rollers, sheared
into blanks, and transferred several successive forming stages, during which it is upset,
preformed, final forged, and pierced (if necessary). This process can also be couple with
high speed cold forming operations. Generally, the cold forming operation will do the
finishing stage so that the advantages of cold-working can be obtained, while maintaining
the high speed of automatic hot forging.
Roll forging Roll forging is a process where round or flat bar stock is reduced in
thickness and increased in length. Roll forging is performed using two cylindrical or
semi-cylindrical rolls, each containing one or more shaped grooves. A heated bar is
inserted into the rolls and when it hits a stop the rolls rotate and the bar is progressively
shaped as it is rolled out of the machine. The work piece is then transferred to the next set
of grooves or turned around and reinserted into the same grooves. This continues until the
desired shape and size is achieved. The advantage of this process is there is no flash and
it imparts a favorable grain structure into the workpiece.
Powder metallurgy is a forming and fabrication technique consisting of three major
processing stages. First, the primary material is physically powdered, divided into many
small individual particles. Next, the powder is injected into a mold or passed through a
die to produce a weakly cohesive structure (via cold welding) very near the dimensions of
the object ultimately to be manufactured. Pressures of 10-50 tons per square inch are
commonly used. Also, to attain the same compression ratio across more complex pieces,
it is often necessary to use lower punches as well as an upper punch. Finally, the end part
is formed by applying pressure, high temperature, long setting times (during which self-
welding occurs), or any combination thereof.
Two main techniques used to form and consolidate the powder are sintering and metal
injection molding. Recent developments have made it possible to use rapid
manufacturing techniques which use the metal powder for the products. Because with this
technique the powder is melted and not sintered, better mechanical strength can be
accomplished.
Solid state sintering is the process of taking metal in the form of a powder and placing it
into a mold or die. Once compacted into the mold the material is placed under a high heat
for a long period of time. Under heat, bonding takes place between the porous aggregate
particles and once cooled the powder has bonded to form a solid piece.
Sintering can be considered to proceed in three stages. During the first, neck growth
proceeds rapidly but powder particles remain discrete. During the second, most
densification occurs, the structure recrystallizes and particles diffuse into each other.
During the third, isolated pores tend to become spheroidal and densification continues at
a much lower rate. The words Solid State in Solid State Sintering simply refer to the state
the material is in when it bonds, solid meaning the material was not turned molten to
bond together as alloys are formed.
One recently developed technique for high-speed sintering involves passing high
electrical current through a powder to preferentially heat the asperities. Most of the
energy serves to melt that portion of the compact where migration is desirable for
densification; comparatively little energy is absorbed by the bulk materials and forming
machinery. Naturally, this technique is not applicable to electrically insulating powders.
To allow efficient stacking of product in the furnace during sintering and prevent parts
sticking together, many manufacturers separate ware using Ceramic Powder Separator
Sheets. These sheets are available in various materials such as alumina, zirconia and
magnesia. They are also available in fine medium and coarse particle sizes. By matching
the material and particle size to the ware being sintered, surface damage and
contamination can be reduced while maximizing furnace loading
Testing.
Dynamometers
Eddy Current (35 hp - 800 hp)
AC and DC (400 hp - 800 hp) (Transient / FTP Capable)
Engine Mapping
Component Level Testing
Environmental Condition Capability
Product Validation
Catalyst Aging (Gasoline and Diesel)
RAT-A / ARB approved catalyst aging
DPF, DOC, SCR, NAC/LNT Testing
HC and Urea Injection Development
Trans Shift Tests
Cold Start / Thermal Shock / Rapid Cool-down
Sensor Aging
Full Power train Tests
Stationary / Genset emissions and development
Hybrid systems testing
Fuel Cell Testing
Hot Testing / "End of Line" Audit Tests
Hundreds of available Analog & Digital Channels per test stand
Customer Specific Data Formats
Remote Communications
Emissions (Gasoline and Diesel)
18" Horiba 4000 SCFM Full Dilution Tunnels
Partial Flow Dilution Tunnels (mini-dilution tunnels)
Double or Single Dilution
(70mm filter & 47mm filter for 2007 regulations)
MKS & Horiba FTIR Analyzers
Up to 23 Unregulated Emissions
Pre or Post Catalyst Measurement
Horiba MEXA Analytical Benches
Horiba Micro-Bench Analyzer
AVL Micro-Soot 483 and AVL Smoke Meters
Class 6 Clean Room / Filter Weighing (2007 CFR compliant)
Facilities
23,000 sq ft (Building 1)
25,000 sq ft (Building 2)
45,000-gallon total underground fuel storage
3 gasoline, 2 diesel fuels available
Fuel measurement (+/- 0.5%) in all cells
Component Testing
Misc Tests
Fan Clutch Testing
One-Way-Clutch Alternator Pulley Cycle Tests
NVH measurement and data analysis
"Stretchy" Belt Durability Tests
"Stretchy" Belt Temp vs. Tension Studies
Component Aging / Durability
Power Steering Cold Start Torque Tests
Cylinder Head Motoring Tests
Idler Durability
Tensioner Damping Studies
Belt Tracking Studies
Vehicle Instrumentation
Dedicated Test Stands
Idler Durability
Dynamic Belt Friction
Belt Misalignment
Parasitic Loss
Bearing Noise/ Durability
Deceleration Testing
Environmental Capabilities
Engine Lift Eye Drop Test
Hydrothermal Oven Aging (Catalyst Aging)
Electronics Support
In-House Data Acquisition & Control
Custom Hardware/Software Integration
Custom PC Based Software Application Programming
Electronic Circuit Board Design & Manufacturing
Alternative Fuel Testing
CNG and CNG Conversion Certification
Propane and Propane Conversion Certification
Ethanol Certification
Bi-Fuel (CNG + Gasoline, or Propane + Gasoline) Certification
Bio-Diesel
Hot Testing
Testing took another step in providing full service to our valued customers in the area of
high volume production hot testing. Today, we have supported dozens of engine
platforms and tested over 250 thousand engines while supplying engine plants around the
world. Quality hot testing has become an integral part of our business, both locally and as
satellite operations, with the implementation of our portable hot test cells.
UNIT III ENGINE AUXILIARIES
A carburetor basically consists of an open pipe, a "throat" or "barrel" through which the
air passes into the inlet manifold of the engine. The pipe is in the form of a venturi it
narrows in section and then widens again, causing the airflow to increase in speed in the
narrowest part. Below the venturi is a butterfly valve called the throttle valve — a
rotating disc that can be turned end-on to the airflow, so as to hardly restrict the flow at
all, or can be rotated so that it (almost) completely blocks the flow of air. This valve
controls the flow of air through the carburetor throat and thus the quantity of air/fuel
mixture the system will deliver, thereby regulating engine power and speed. The throttle
is connected, usually through a cable or a mechanical linkage of rods and joints or rarely
by pneumatic link, to the accelerator pedal on a car or the equivalent control on other
vehicles or equipment.
Fuel is introduced into the air stream through small holes at the narrowest part of the
venturi. Fuel flow in response to a particular pressure drop in the venturi is adjusted by
means of precisely-calibrated orifices, referred to as jets, in the fuel path.
Venturi Types
VARIABLE VENTURI CARBURETOR
FEEDBACK CARBURETOR SYSTEM
Electronic Idle-Speed Control
Typical EFI components
Animated cut through diagram of a typical fuel injector. Injectors
Fuel Pump
Fuel Pressure Regulator
ECM - Engine Control Module; includes a digital computer and circuitry to communicate with sensors and control outputs.
Wiring Harness
Various Sensors (Some of the sensors required are listed here.)
Crank/Cam Position: hall Effect sensor
Airflow: MAF sensor, sometimes this is inferred with a MAP sensor
Exhaust Gas Oxygen: Oxygen sensor, EGO sensor, UEGO sensor
Radiators are heat exchangers used to transfer thermal energy from one medium to
another for the purpose of cooling and heating. The majority of radiators are constructed
to function in automobiles, buildings, and electronics. The radiator is always a source of
heat to its environment, although this may be for either the purpose of heating this
environment, or for cooling the fluid or coolant supplied to it, as for engine cooling.
From an engineering perspective, a radiator varies from an ideal black body by a factor,
ε, called the emissivity, which is a spectrum-dependent property of any material.
Commonly, a fluid thermal mass, containing the heat to be rejected, is pumped from the
heat source to the radiator, where it conducts to the surface and radiates into the
surrounding cooler medium. The rate of heat flow depends on the fluid properties, flow
rate, conductance to the surface, and the surface area of the radiator. Watts per square
metre are the SI units used for radiant emittance. If the system is not limited by the heat
capacity of the fluid, or the thermal conductivity to the surface, then emittance, M is
found by a fourth-power relation to the absolute temperature at the surface. The Stefan-
Boltzmann constant is used to calculate it, as M = εσT4. Since heat may be absorbed as
well as emitted, a radiator's ability to reject heat will depend on the difference in
temperature between the surface and the surrounding environment.
The axial-flow fans have blades that force air to move parallel to the shaft about which
the blades rotate. Axial fans blow air along the axis of the fan, linearly, hence their name.
This type of fan is used in a wide variety of applications, ranging from small cooling fans
for electronics to the giant fans used in wind tunnels.
Fans
Basic elements of a typical table fan include the fan blade, base, armature and lead wires,
motor, blade guard, motor housing, oscillator gearbox, and oscillator shaft. The oscillator
is a mechanism that moves the fan from side to side. The axle comes out on both ends of
the motor, one end of the axle is attached to the blade and the other is attached to the
oscillator gearbox. The motor case joins to the gearbox to contain the rotor and stator.
The oscillator shaft combines to the weighted base and the gearbox. A motor housing
covers the oscillator mechanism. The blade guard joins to the motor case for safety.
In automobiles, a mechanical fan provides engine cooling and prevents the engine from
overheating by blowing or sucking air through a coolant-filled radiator. It can be driven
with a belt and pulley off the engine's crankshaft or an electric fan switched on or off by a
thermostatic switch.
Coolant pumps
Thermosysphon cooling system of 1937, without circulating pump Radiators first used
downward vertical flow, driven solely by a thermosyphon effect. Coolant is heated in the
engine, becoming less dense and so rising, cooled, denser coolant in the radiator falling in
turn. This effect is sufficient for low-power stationary engines, but inadequate for all but
the earliest automobiles. A common fallacy is to assume that a greater vertical separation
between engine and radiator can increase the thermosyphon effect. Once the hot and cold
headers are separated sufficiently to reach their equilibrium temperatures though, any
further separation merely increases pipe work length and flow restriction.All automobiles
for many years have used centrifugal pumps to circulate their coolant, driven by geared
drives or more commonly by a belt drive.
IGNITION SYSTEM
PRIMARY IGNITION SYSTEM
The primary system consists of the ignition switch, coil primary windings, distributor
contact points, condensor, ignition resistor, and starter relay.
Ignition Switch. First, it turns on the car's electrical system so that all accessories can be
operated. It does so by providing power to the fuse panel (for those components that are
controlled by the switch. Some items are independent of the ignition switch, such as
headlights, horn, clock, etc.) When you insert the key and turn the switch to the
"accessories" position, you are turning on the other devices in the car, such as the radio,
heater, power windows, seats, defroster, etc.
Second, in the run position, everything is turned on, plus the engine's electrical
components that enable it to run. Most important, it turns on the entire primary ignition
system. Wait a minute! We just learned that the starter takes enormous current from the
battery through its thick cable. How can the ignition switch carry so much current if there
isn't a battery cable connected to it?
The ignition switch doesn't carry the necessary current to the starter. It sends a small
current to a special device called a Relay that, in turn, allows the starter to crank. We'll
discuss that later in this article. Back to the primary ignition system...
The next component is the coil's primary winding. Inside the coil are two sets of wound
wire, comprising of the primary and secondary windings. The primary windings carry
battery voltage through and create a large magnetic field inside the coil (this is discussed
thoroughly in the section on secondary windings). Although the coil's primary windings
receive voltage from the ignition switch, they are actually turned on and off by the
distributor's contact points.
The contact points are opened and closed by a cam on the distributor's main shaft. As it
spins the cam's lobes move the actuator outward, disengaging the contacts. When the lobe
passes, the contacts close, turning on the coil primary windings. The amount of time the
points remain closed is referred to as dwell, and is an important factor in engine tuning.
Attached to the points is a condensor, an electrical device (capacitor) that limits current
flow through the points to increase their life. The condensor is necessary because the
points are opening and closing rapidly, and as they do so the voltage/current is
interrupted. This causes an arc, or spark, between the contact points. Over time, this
arcing will erode the material on the points and deposit carbon, and eventually the points
will not pass current. The condensor acts as a current-absorber to limit the amount of
arcing as the points open and close.
The next component is the ignition resistor. It is necessary because ignition coils are
designed to step up battery voltage high enough - and fast enough - to keep the engine
running at high rpm. That means that, as designed, the coil would produce too much high
voltage at low rpm and heat up. Automakers long ago realized that there were two
solutions to the problem: using two coils (one for low rpm and one for high) or an
ignition resistor. Obviously, the resistor approach is the least expensive and most reliable,
so that's what they did. The resistor used varies is resistance as a function of temperature,
and limits the voltage to the coil accordingly. As the engine revs up the resistance lowers,
allowing more voltage to the coil for fast running, and the reverse happens when the
engine slows down. At idle, for instance, only about 7 volts is going through the coil
primary windings.
The only time the resistor is out of the circuit is during startup, when the engine needs all
the spark it can get. It's bypassed in the ignition switch's start position so that, during
starting, the coil gets full battery voltage. Ignition resistors can take many forms,
depending upon the manufacturer of the vehicle. Some builders mounted a big resistor on
the firewall and some others utilized a special type of wire (resistance wire) running from
the ignition switch to the coil. Still others used coils that were built with an internal
resistor. None of these is any better an approach than the others, but it's important to
know which type you have, and that you have one!
SECONDARY IGNITION SYSTEM
The secondary ignition system consists of the coil secondary windings, distributor cap,
rotor, plug wires and spark plugs.
Coil Secondary Windings
So just how does a coil work? Well, the principle of Inductance is the answer. Physics
tells us that if you put a certain voltage through a wire (the primary) that has another wire
wrapped around it, the second (hence, secondary) wire will receive an "induced" voltage
from the first. Furthermore, the "induced" voltage is a function of the number of turns of
wire wrapped around, so if you have two coils wrapped around the wire you'll get twice
the voltage, and so on. Voltage can be stepped-up and stepped-down using inductance.
Transformers are inductance devices, so a coil is a transformer.
Automotive coils generally have secondary-to-primary ratios of 200 to 1. Therefore, a 12-
volt input to a coil's primary windings will result in a 24,000-volt output from the
secondary winding. That's where the spark plugs get their electricity.
Inductance isn't perpetual motion, nor is it "free energy." There are many "howevers" and
other considerations to worry about. The biggest one is the coil's inability to hold the
induced voltage once it's been built up. In a very short time the voltage will "bleed of,"
leading to weak spark. Also, the coil takes a finite amount of time to build the charge up.
That's the dwell time, normally defined as the degrees of rotation of the camshaft
during which the points are closed. Too little dwell and the coil doesn't have time to
charge up fully. Too much dwell and the coil has bled off some charge, causing a weak
spark. Hesitation, low power, misfiring, pinging and a number of other conditions are
symptoms of incorrect dwell.
UNIT IV COMPUTER INTEGRATED MANUFACTURING
CAM Management Solutions’ Integrated Strategic Planning and Performance Management Solution is developed on the following framework as we believe a monitoring system should facilitate:
Full integration of strategic, business, service and annual planning
Implementation & management of a conceptual framework which links to
Sustainability and partnerships
Performance management that is linked to planned outcomes
Integration of policy and governance into all planning levels
Integration of the community into the corporate planning process
CIM NETWORKING
Virtual corporations, enterprise re-engineering, and adaptive/agile manufacturing are
all new concepts based on the accomplishments of integrated manufacturing of the past
decade. The new manufacturing enterprises are characterized by ability to effect
flexible reconfiguration of resources, shorter cycle times and quick response to
customer demands. Information is a key factor in transcending physical barriers and
imparting the enterprise-oriented agility and adaptiveness to organizations. To this end,
a theory-based reference model for information integration is needed in manufacturing
enterprises. Employs the paradigm of parallel formulation as the reference model and
demonstrates how it is used to guide the planning for information integration. The
model provides both a detailed data and task analysis of manufacturing functions and
their interactions, and guidelines for regrouping tasks into parallel processes and
thereby achieving a high level of global integration. Describes a case study of the
model, conducted on the existing CIM model at Rensselaer to evaluate and reformulate
the previous processes. The results show a better design featuring concurrent execution
of functions which in turn support agility and adaptiveness.
CNC Machine Programming
The major manufacturing steps involved in making sheet metal enclosures are sheet
shearing, hole punching and press brake folding. All these steps are done on computer
controlled CNC machines. So CNC programming is a crucial step in making high quality
products.
The first step is to convert a sheet metal enclosure design into flat patterns as if the part
was unfolded.
The next step is to determine bend allowances and offsets for their particular machines.
With these numbers, we can program the various pieces of equipment to minimize waste
and provide the accuracy you require.
For small quantities of parts, the majority of the cost is in programming and setup. The
price curve for any quantity over 25 parts flattens out as the programming is spread out
over more and more parts.
UNIT V QUALITY AND TESTING
Indian Standards
Bureau of Indian Standards (BIS) Publications
Quality Management
Quality Management standards that are not covered in ISO 9001/14001 Standards are given here.
S.No. BIS Number Title
1 IS/ISO 10019: 2005
Guidelines for the Selection of Quality Management System Consultants and use of their Services (800 Kb)
2 IS/ISO/TS 16949: 2002
Quality Management Systems - Particular requirements for the application of ISO 9001:2000 for Automotive Production and relevant Service part Organisations (2.4 Mb)
3 lS/lSO/lEC 20000-1: 2005
Information Technology - Service Management Part-1 Specification (1.0 Mb)
Computer aided engine testing
Metrology for manufacturing Engine Components
Dimensional Metrology
In general, there will be errors of size in any machined work piece. This means that the
actual dimension will be different from nominal dimension. These errors should be
within certain given limits by tolerances and determined by the dimensional measurement
to guarantee the product quality. The dimensional measurement includes:
Post-process Dimensional Measurement
Block Gauge
Micrometer
Profile Projector
Coordinate Measurement Machine (CMM)
On-process Dimensional Measurement
Mechanical Methods
Optical Methods
Pneumatic Methods
Ultrasonic Methods
Post-process Measurement
Traditionally, measurements have been made after the part has been produced. It is called
the post-process measurement. The post-process measurement can be used to high
production run of smaller parts. The inspection process can be made by traditional
methods. If the dimensions are not within the given tolerance zone, a correction can be
made to the next part through the machine tool.
Block Gauge
Gauge blocks are Individual Square, rectangular, or round metal blocks of various sizes.
Their surfaces are lapped and are flat and parallel within a range of 1-5 micro inch. Gage
blocks are available in sets of various sizes. The blocks can be assembled in many
combinations to obtain desired lengths. The gage block assemblies are used as an
accurate reference length to measure the part's length.
Micrometer
The micrometer is commonly used for measuring the thickness and inside or
outside diameters of parts. Micrometers are also available for measuring depths.
Micrometers can be equipped with digital readout to reduce errors in reading.
Profile Projector
The profile projector is used for measuring two-dimensional contours of precision
specimens and other work pieces produced. The part to be measured is magnified
by an optical system and projected on a screen. The reading on the screen gives
the dimension of the part. The following is the photo of a profile projector.
Coordinate Measurement Machine (CMM)
A coordinate measurement machine (CMM) is an advanced, multi-purpose
quality control system used to help inspection keep pace with modern production
requirements. It replaces long, complex and inefficient conventional inspection
methods with simple procedures. A CMM provides instant measurement results
without complicated setup and operating procedures. It combines surface plate,
micrometer and vernier type inspection methods into one easy to use machine.
CMM can check the dimensional and geometric accuracy of everything from
small engine blocks, to sheet metal parts, to circuit boards.
A CMM consists essentially of a probe supported on three mutually perpendicular
(X, Y & Z) axes. Each axis has a built-in reference standard.
Procedure for simple measurements on a CMM includes:
Calibration of the probe system.
Define datum(s) on the work piece.
Perform measurement(s).
Compute the required dimensions from measurements made in Step 3.
Assess conformance to specification.
On-process Dimensional Measurement
When the manufactured parts are big, with higher material cost and longer cycle times,
on-process measurement is required to improve the productivity and reduce the cost. In
the on-process measurement, parts are measured while they are on the machine tool.
The existing on-process measurement methods can be divided into direct and indirect
methods according to the measurement principle.
Direct methods. In direct method, the dimension of the work piece is directly measured
using an adequate instrument, while the work piece is located on the machine tool.
Therefore, the effects of tool wear distortions and machine errors can be taken into
account.
Indirect methods. The work piece accuracy can also be indirectly evaluated from radius
measurements, by monitoring the motions of the carriage, carrying the cutting tool or by
noting the position of the tip of the cutting tool.
The on-process measurement can be implemented by several methods. Here are several
on-process dimensional measurement methods:
Mechanical Methods
Caliper Type
A typical caliper type contact gauge consists of a simple scissors caliper with non rotating
circular contact pads. The instrument can be set to measure over a range of diameters.
The contact pads or jaws are in continual rubbing contact with the work piece. It is
attached to the machine bed on its own slide so that it can be rapidly withdrawn and
returned to the measuring position in a repeatable manner. The rear gap of the scissors is
bridged by sensing element, which can be a pneumatic or electrical transducer. The
caliper is set with respect to a circular setting master. it is possible to derive an electrical
signal with both types of transducer, which can be used to control the machining process
such as grinding and turning. The measured work piece diameter range with this method
reaches 5-190mm and repeatably is 0.5 um.
Friction Roller Type
This method measures the perimeter of the work piece by counting the number of
revolutions of the measuring roller for one or more complete revolution of the work piece
as illustrated in the following figure. The application of this method is restricted to rigid
work piece, due to the high pressure applied by the roller. This technique has been used
in turning and grinding.
Probe Type
A probe in mechanical contact with the work piece is used to determine the actual size of
work piece. For the gauging process, the probe is moved towards the work piece and
deflected by the contact. The coordinate value of the point of the touch makes it possible
to determine the work piece radius provided the position of the axis of rotation is known.
Optical Methods
An optical method of on-process measurement is defined as one in which the transmitter
module produces and emits a light, which is collected and photo electrically sensed
through the object to be measured, by a receiver module. This produces the signals which
can be converted into a convenient form and displayed as dimensional information. The
principal advantages of optical methods are
Direct mechanical contact between the sensor and the object to be measured is not
required.
The distance from the object to be measured to the sensor can be large.
The response time is limited only to the electronics used in the sensor.
The light variations can be directly converted into electrical signals.
The main optical on-process measurement methods include:
Scanning Light Beam
This technique uses laser beams for the measurement process. It employs transmitted
module which emits a high speed scanning laser beam, generally by means of a
combination of a mirror and a synchronous motor. The object to be measured interrupts
this beam, and produces a time dependent shadow. This shadow is electrically detected
by a receiver, and converted into dimensional readings by a control unit.
Machine Vision
The method uses a light source and the image of the work piece can be focused on the
measuring grid on the face of a television tube or CCD (Charge coupled device). Then
the diameter of the work piece is computed in terms of the image parameters, such as the
image application factor, focal distance and the image length on CDD.
Some other optical methods exist. For example,
Light gauging
Light focusing
Light-spot detection
Light sectioning
Pneumatic Methods
This method measures a pressure drop in the gap between the air gauge and work piece,
and converts it into an electrical signal. A schematic diagram of pneumatic method is
shown as the following.
Ultrasonic Methods
In this method, ultrasound travels to the work piece, then reflects back to the transducer
which also acts as a receiver. The transit time depends on the variation from the specified
distance between work surface and transducer. By determining the transit time, the
distance can be calculated.