NOTES ON POWDER METALLURGY !!

Powder metallurgy is a metalworking process for forming precision metal components from metal powders by compacting in a die.

Process Details:

The following are the basic steps of powder metallurgy:

1. Power production: Numerous processes can produce metallic powders: grinding, electrodeposition, comminution, atomization, chemical reduction, etc. In atomization, a liquid metal stream produced by injecting molten metal through a small orifice and the steam is broken up by jets of inert gas, air or water. The powder is also produced by reduction of metal oxides using hydrogen or carbon monoxide, as reducing agents. Mechanical comminution involves crushing, milling in a ball mill or grinding brittle or less ductile metals into small particles.
2. Powder Mixing: The process of mixing includes mixing of various metal powders are thoroughly intermingled. This is carried out in batch mixers. The temperature during mixing affects the friction between powder particles. With increasing temperature, the friction coefficient between most materials increases and the flow of powders is impaired.
3. Compacting: A controlled amount of the mixed powder is introduced into a precision die, and then it is pressed or compacted at room temperature and pressure in the range 100 Mpa to 1000 Mpa. In doing so, the loose powder is consolidated and densified into a shaped model. The model is called green compact. As it comes out of the die, the compact has the size and shape of the finished product. The strength of the compact is just sufficient for in-process handling and transportation to the sintering furnace.
4. Sintering: Sintering involves heating of the green compact in a protective atmosphere furnace to a suitable temperature below the melting point of the metal. Typical sintering atmospheres are endothermic gas, exothermic gas, dissociated ammonia, hydrogen, and nitrogen. Sintering is responsible for producing physical and mechanical properties by developing a metallurgical bond among the powder particles. It also serves to remove the lubricant from the powder, prevents oxidation, and controls carbon content in part.

Application:

Some prominent powder metallurgy products are as follows:

1. Filters: Powder metallurgy filters have greater strength and shock resistance than ceramic filters. Fiber metal filters, having porosity up to 95% and more, are used for filtering air and fluids.
2. Cutting Tools and Dies: Cemented carbide cutting tool inserts are produced from tungsten carbide powder mixed with a cobalt binder.
3. Machinery Parts: Gears, bushes, and bearings, sprockets, rotors are made from metal powders mixed with sufficient graphite to give the product desired carbon content.
4. Bearing and Bushes: Bearing and bushes to be used with rotating parts are made from copper powder mixed with graphite.
5. Magnets: Small magnets produced from different compositions of powders of iron, aluminum, nickel, and cobalt have shown excellent performance, far superior to that cast.

FUEL CELL : INTRODUCTION AND WORKING EXPLAINED !!

Fuel Cell Technology which is expected to do wonders once accepted globally. A fuel cell is an electrochemical cell converting energy from a fuel into electrical energy and reactions taking place between the fuel supply and an oxidizing agent result in the generated electricity.

Making it more convenient to understand we can say that a fuel cell converts the chemicals hydrogen and oxygen into water, and in the process it produces electricity. Another very common example of an electrochemical device is a battery which is used almost everywhere.

But of all the characteristics the most important one of a Hydrogen Fuel Cell is that it is capable of staying alive for a much longer period as compared to the conventional battery which becomes dead after a couple of hours or days or at most a few months.

Hydrogen Fuel Cell Working :

Fuel cells are of several types but the most promising and efficient is the one we are going to explain here. Called as Polymer Exchange Membrane Fuel Cell (PEMFC), this type is most suitable for powering car, buses and even houses. The working of the same uses one of the simplest reactions of any fuel cell and constitutes of an Anode, Cathode, and Electrolyte and a Catalyst.

•          The negative anode plays the role of conducting the electrons that are freed from the hydrogen molecules and also disperses Hydrogen gas equally over the catalyst.
• 
  
•          The channels located on the Cathode as well perform the task of distributing oxygen over the catalyst and also conducts the electrons to the catalyst from external circuit.
• 
  
•          A proton exchange membrane acts as the electrolyte which only allows positively charged ions to pass through it and hence blocks electrons.
• 
  
•          The catalyst is an important constituent which enhances or speeds up the reaction between hydrogen and oxygen.

Working: Now what happens is that Hydrogen gas enters the fuel cell from the anode part where it is split into two H+ ions after being forced through the catalyst. The electrons thus flow into the external circuit and perform the required work like turning a motor etc. and return to the cathode.

Meanwhile Oxygen gas is forced through the catalyst after entering from the cathode side where it is split into two negative oxygen atoms.

    At last the negative oxygen ions attract the lighter hydrogen ions through the membrane eventually combining and resulting in Water(H2O).

CHECK OUT WHY FLYWHEEL IN ENGINES ARE TOOTHED !!

In general, power is only generated during power stroke while power is consumed during the rest three strokes (i.e. Suction stroke, Compression stroke and Exhaust stroke).A flywheel is large diameter metal disk attached to the crankshaft of the engine. High moment of inertia of this metal disk makes it difficult to rotate and stop (Newton's first law). It stores the power produced during power stroke and provides this energy during the power consuming strokes.

When electric starters came into the picture we needed to mesh the teeth of electric motor pinion with something to achieve high gear ratio for the required torque.That is where the starter motor engages with the engine to provide that initial torque. The teeth on the flywheel mesh with the pinion coming out of the starter motor.

It has nothing to do with weight reduction. In fact, the whole point of the flywheel is to have a rotor of higher mass to smoothen out the engine output power fluctuations.

Also See-CHECK OUT THE REASON FOR LARGER DISC BRAKE AT FRONT AND SMALLER AT REAR

KNOW THE MEANING OF A/F ON NUMBER PLATE IN NEW VEHICLES !!!!

A/F stands for Applied For. This was a previous notation on the newly bought number plates of the vehicles. Every vehicle needs to be registered under the Motor Vehicle Act 1989.

Yes,it's illegal to drive with an A/F plate in India and can attract heavy fine and even car can be bonded. Every car that rolls off the showroom now gets either a temporary number or a permanent number according to the state.

The Central Motor Vehicles Rules (CMVR) do not allow driving a vehicle without registration. To drive a vehicle even with the `A/F' (Applied For) status is an offence. "It is a misconception that people can drive with an A/F tag,"

KNOW WHAT WILL HAPPEN IF YOU BLOCK YOUR ENGINE EXHAUST !!

If someone blocked it successfully the engine would stop because it can't expel the exhaust gas on the second stroke of the piston.Damage to the engine would be highly unlikely.The engine is basically a big air pump. Air is drawn into the engine through the air filter and the fueling system by the movement of the pistons. As the piston moves down, valves open on the air filter side allowing air to fill the piston. As the piston move back up after compression and ignition, the valves on the exhaust side open allowing the air to be pumped to the exhaust system. If the exhaust system won’t allow any air out, the engine won’t run as it won’t be able to draw air and fuel into the engine. Air has to have somewhere to go for it to flow.

DIFFERENCE BETWEEN BRAKE FADE AND BRAKE DRAG EXPLAINED !!

Brake fade-Since during braking of a vehicle a large amount of heat is generated and the brakes drums and discs are forced to absorb this.Hence brake fade describes a condition where heat is generated at a faster rate than they are capable of dissipating into the surrounding.

Since the brake pad is fixed with some adhesive material hence when such large temperatures are achieved during braking this adhesive material starts to vapourise and forms a layer between the disc rotor and brake pad there by decreasing the braking force(as the layer formed is compressible)which in turn reduces the braking efficiency of the vehicle.Also the friction material overheats and the coefficient of friction drops off significantly which also reduces the braking ability of brakes.

Brake drag-It is the rolling drag that brakes incur at elevated temperatures.This problem can be caused by several occurrences from failing of master cylinder to misalignment of brake calipers.Generally brake drag is caused due to incomplete brake shoe release.

Or by broken or weak springs on drum brakes.Or may be due to corroded or jammed caliper piston.Also brake drums that have defective linig material,out of round(elliptical),have clogged lines or hoses or loose anchor pins can also cause brakes to drag.

TWO MOTORBIKES WITH SAME CUBIC CAPACITY BUT DIFFERENT MILEAGE !!! WHY ??

You might have noticed that motorbikes having same cubic capacity gives different mileage. For Example,Bajaj Platina has cubic capacity of 100 CC and it gives mileage of 104 kmpl,on the other hand Hero Splendor is also having same cubic capacity but it gives the mileage of 81kmpl.

It is mainly because the bikes like Platina has been made keeping in mind mileage.Parts are light to keep bike weight low.Carburetor is tuned to extract mileage though it puts a strain on engine which you can judge from harsh engine note.If you race it will shudder as it puts strain on engine.Also it gives Low torque, low BHP, and leaner air fuel mixture. Tyres are slim for less friction with road.All this saves you petrol but at a high maintenance cost & low resale value.High maintenance cost can be curtailed with regular servicing but if you give less petrol to engine then wear & tear will be more anyway.

NITRIDING PROCESS EXPLAINED !!

Nitriding is the diffusion of nitrogen into the surface of special alloy steel to give a hard surface and soft core without the need for further treatment. Processing is generally carried out in the temperature range 470ºC to 530ºC in an atmosphere of ammonia, although other processing media can be used, such as salt baths and plasma.

Nitriding is only carried out on special alloy steels containing chromium or aluminium. It is the reaction of the nitrogen with these alloy elements that causes the hardening, so that, unlike carburising and carbonitriding, quenching is not required after processing. The nascent nitrogen is obtained from an atmosphere of ammonia gas, which at 500°C dissociates into its constituent elements, nitrogen and hydrogen. The nitrogen, which is in solution in the iron, diffuses inward and forms aluminium or chromium nitrides producing high hardness in the surface of the nitrided component. A layer of iron nitride and alloy nitrides forms on the surface (the "white layer''). Since this is brittle it is normally removed from bearing surfaces before service. As with carburising the case depth is time and temperature dependent.

Nitriding produces advantages in addition to a freedom from distortion, which is due to the low treatment temperature and the fact that quenching is not required.

Materials that can be nitrided include low carbon steels, which will develop file hardness, alloy steels such as 4130, 4140, 4340 and Nitralloy 135M which are the most common nitriding steels and special application steels including, mold steels (P-20), air hardening tool steels (A-2 and D-2), hot work and shock steels (H-13 and S-7), high speed steels (M-2, M-4 and M-42), and stainless steels (304, 316, and 17-4 PH).

A prime application for nitriding is plastic injection mold components, including screws, tips and barrels. The hardness of the nitrided layer is especially useful in reducing wear from plastic molding, particularly when abrasive plastics like glass filled polymers are extruded.

18 CYLINDERS !!! 2000 HORSEPOWER !! 4600 CC !!! WATCH THIS GIANT IN ACTION THROUGH CUTAWAY !!

The R-2800 Double Wasp is an American made, 18-cylinder radial engine which was the most powerful engine of its type in the world during that time. Designed in early 1930s and first tested in 1937, it is still considered one of the best piston engines ever designed. Arriving right before World War II, the original 2,000 horsepower it generated made it ideal for placement in war planes.

WATCH THE WORKING CUTAWAY IN THE VIDEO BELOW :

 

WHICH ENGINE OIL IS BEST SUITED FOR YOUR VEHICLE? SYNTHETIC OR MINERAL?? CHECK OUT THE ANSWER !!!

There are 3 types of motor oil or engine oil used for the lubrication of engine. Engine oil is the most vital and essential one for an engine to function properly. The three types in general are mineral oil - derived from petroleum based products, fully synthetic - completely artificial and synthesized in labs. semi-synthetic- a blend of synthetic and mineral oil in definite proportions. 

Generally an engine oil has many benefits like lubricating the engine, carries away the heat produced during operation, reduces friction, wear and tear of the internal components and keeping the engine clean, free from sludge combustion and carbon deposits.

Synthetic oil is not only refined but also distilled, purified and broken down into its basic molecules. This process not only removes more impurities from the crude oil but also enables individual molecules in the oil to be tailored to the demands of modern engines. These customized molecules provide higher levels of protection and performance than conventional oils. A fully synthetic motor oil or engine oil is widely used in high performance motorcycles and cars. The main advantage of using a fully synthetic engine oil is that it maintains its stability and viscosity (thickness) even at very high temperatures. Hence it protects engine and its components during high speeds and long run. Superbikes in the world like Yamaha R1, Suzuki Hayabusa and MotoGp racing bikes, high performance cars use fully synthetic engine oils.

Fully synthetic engine oils provides better engine protection than any other type of motor oils. The advantages of using a fully synthetic oil is that it provides better engine performance, less engine heating, improved acceleration and more interval of oil change. It lasts longer than mineral and part synthetic oils.

But all this advanced technology doesn't come cheap. A synthetic oil change can cost over twice as much as conventional oil.but is it worth it beyond its obvious better performance characteristics?

This is not exactly a straight yes or no answer to go along with this question as there are several variables to consider, but in general, most experts would agree that synthetic is (for now) the lesser of the two evils.

Their logic stems from the fact that while conventional oil is evil because it is derived from petroleum, synthetics are unfortunately formed by chemicals that are no less harmful to the environment... but there is a difference here. Synthetics can last as much as three times longer than conventional oil.

With todays technology, synthetics are cleaner and meaner (just not necessarily any greener). Their composition is much cleaner, because it is derived in a laboratory rather than nature, and it has been proven to have a lower volatility and therefore not vaporize out the exhaust as quickly.

If you want to be on the safe side, you can follow what your manufacturer recommends as far as oil goes. In general more performance oriented vehicles require synthetic because of the high heat that builds in these engines, whereas conventional engines don't require anything special.

COMPLETE NOTES ON ENGINE OIL !!

A car's engine is the "heart" of the vehicle and needs to be maintained with the proper amounts of motor or engine oil. 

The oil used in automobile has two primary ingredients: base oil and additives. The base oil allows the motor oil to perform its vital function - lubricating the engine's moving parts to protect them against wear and tear caused by friction. The additives provide additional engine protection by helping to prevent the oil from deteriorating under the engine's extreme temperature conditions.Engine oil typically consists of about 80% base oil and 20% performance additives. The performance additives include anti-wear additives, antioxidants, dispersants and detergents that keep the engine clean, and viscosity index improvers that ensure the oil maintains an optimum viscosity throughout the engine’s operating temperature range. The base oil carries these additives to where they are needed, and provides vital cooling to engine components, by drawing away heat. Base oils can be either mineral or synthetic, and engine oils can contain all mineral base oil, all synthetic base oil, or a mixture of the two. Engine oils containing a mixture are typically described as part-synthetic.

Functions of Engine Oil :

Corrosion Inhibitors Protect the engine against corrosion and wear & tear as oil begins to oxidate, ensuring an increased engine life and better performances.

Reduces metal to metal contact between the moving parts of the engine by separating them with a film of oil. This reduction in friction increases engine performance & reduces fuel consumption.

Detergents that are part of the additive packages Remove impurities to the oil filter and clean existing deposits and foreign substances in the engine, achieving engine cleanliness & preventing it from serious damage.

Engine Oils act as a Seal space between the piston & cylinder as they are not completely smooth These gaps are filled by the Engine Oil optimising engine performances and efficiency.

The coolant system based in engines cools the upper engine and it’s parts. Engine Oil Cools the engine, preventing energy loss, & engine deterioration.

Importance of Oil Change

Oil is vital to the operation of your motorcycle and operates in three ways: reducing internal friction, cooling the components of the motor, and flushing the motor of debris. Oil lubricates the moving parts in the motor, preventing metal parts from coming into direct contact with each other.

The oil system is designed to catch as much of the contaminants that build up within the motor, straining out any foreign objects as it passes through the oil filter. Changing your oil and filter refreshes this system, removing any build-up and providing fresh lubrication.

Riding conditions that require frequent oil changes

1. Longer rides at high revs.
2. Dusty or humid conditions.
3. Stop-start riding in built-up areas. This puts a lot more strain on the oil than motorway journeys.
4. Using poor quality fuel, which can lead to oil contamination and sludge.

Learn how to read engine oil specifications in the video below :

DIFFERENCE BETWEEN PUSH AND PULL MARKETING EXPLAINED !!

Push marketing is defined as a promotional strategy in which a business attempts to get their message in front of their potential customers without them having a desire or interest to buy the product or learn more about it. Push marketing requires a lot of reach and can be considered to be ‘interruptive’. Just think of radio and TV advertising and how they interrupt your favorite Katy Perry song, or the latest Fox Life TV show. Unless you’re passionate about advertising, then you probably don’t find these ads to be entertaining or informational.

On the other hand, pull marketing takes the opposite approach. Consumers actively seeking out a product define it and the retailer presents his ads, or products, in the path of the consumer.

In order to use pull marketing it requires an interest for the product you’re selling. Back in the day, pull marketing was associated with big brands because you first needed to use push marketing to get a message out and then attracting the consumers using pull marketing.

Promotional push strategies help generate awareness of a new product or service on the market. It can get people to call or visit your business for the first time. Push marketing can be quickly implemented and yield quick results, but has a brief impact on customers. Pull strategies help people sell themselves on your product or service once they’re aware of it. This type of strategy is done in response to what customers need in order to get the most value from an ongoing relationship with your business. Pull marketing can take longer than push marketing to implement or to yield results, but has more lasting impact on customers.

Successful companies combine push and pull strategies as seamlessly as possible for mobile and online marketing. Customers are pushed new product lines, updates, innovations and trial offers. They’re then pulled to develop loyalty as a brand proves that it can provide solutions at a level of quality customers expect, and as customers’ peers also champion the brand’s value. Brand building, acquiring sales and improving the overall customer experience involves an ongoing conversation between companies and customers through increased feedback, sharing and interaction across various digital media

DIFFERENCE BETWEEN KNOCKING AND DETONATION EXPLAINED !!

Both knocking and detonation means sudden increase in pressure inside the cylinder of engine.But,there is a small difference in the way at which they take place.

In a spark ignition engine combustion which is initiated between spark plug electrodes spreads across the combustible mixture. A definite flame front which seperates the fresh charge from the products of combustion travels from spark plug to the other end of combustion chamber. In order to effect pressure equilisation the burned part of the mixture expand, and compresses the unburned mixture adiabatically increasing its pressure and tempetature, The process continues as the flame front advances through the mixture and the tempereture and pressure of the unburned mixture are increased furthur.

If the temperature of unburnt mixture exceeds the self Ignition temperature of the fuel and remains at or above this temperature during the period of pre-flame reactions auto Ignition occurs.This auto-ignition results in sudden rise in pressure.THIS PHENOMENON IS CALLED KNOCKING.This is also called auto-ignition because it is initiated automatically with very less control. 

In diesel engines,during the cold starting conditions a situation might arise in which the vaporization of fuel is limited due to cold combustion chamber. Low vaporization result in misfiring or no combustion at all in cylinders. This results in accumulation of fuel inside combustion chamber. This fuel after certain cycle then burns rapidly, producing tremendous power. This might occur while the engine is in start of compression stroke or exhaust stroke. Hence producing huge stresses within the engine. This phenomenon is called detonation

So in short, knocking occurs in spark ignition (petrol engine) due to auto-ignition of fuel resulting in sudden rise in pressure whereas detonation occurs in compression ignition engine (diesel engine) due to sudden burning of accumulated fuel particles resulting in sudden increase in pressure.

REASONS FOR TYRE WEAR EXPLAINED !!

The treads of tyre wear varies in relation to the type of road surface, the number of curves, the amount of traffic, the temperature and the driving habits of the driver. 

Abnormal wear can be accounted for by such conditions as incorrect-pressure, faulty wheel alignment, faulty brake adjustment and over loading. The probable causes of tyre wear and their remidies are discussed below:

Probable causes of tyre wear

1. Over inflation: The wear in the centre of the tyre tread is increased by excessive internal pressure. 

The air pressure also causes the increase cord stresses which reduce the tyre life. Apart from this the riding comfort is affected and more ear noises e.f. rattles or squaks become accentuated.

2. Under-inflation : Under inflation causes the side-walls of the tyre to bend sharply as the wheel revolves, so that the line the cord breaks and utimately the tyre blows out.

3. Front-wheel-Misalignment : This is a frequent cause of rapid tyre wear. Despite increased steering drag, the irregular tread wear will occur, which will slow feathered edges with a ‘filed’ appearance caused by the constant side grinding effect.

4. Rear-wheel Misalignment : The rear wheels will not be parallel to the centre line of the chassis if chassis frame is distorted. Serious tyre wear will take place due to sideway drag.

5. Defective wheels : wheels can be distorted due to accidents or kerb impact and therefore do not rotate truly on their hubs. As a result excessive tyre wear may be caused. Wheel rims more than 1.5 m.m out of true should be discarded.

6. Excessive Speeds : The tread wear increases fairly with the car speed. Other factors affecting tyre wear are condition of -road surface, curves, temperatures, unbalanced wheels and tyres, neglect of small cuts and oil or grease on the corners.

7.  Excessive Wheel Camber : It results in excessive side wear on the treads. This may be due to incorrect adjustment or some severe accident: which leads to excessive wear in the king-pins and suspension bearings.

8.   Flats on Tyres: Flats are caused by violent braking, resulting in wheels locking, so that the tyres dragged over the road without turning.

WATCH BUGATTI VEYRON RUNNING AT TOP SPEED !!

The Bugatti Veyron EB 16.4 is a two-door mid-engined supercar, which is handbuilt in France. Dreamed up by Volkswagen head honcho Ferdinand Piech, the car was named in the honour of Pierre Veyron, a development engineer and company racer who won the 1939 24 hours of Le Mans in a Bugatti. The 'EB' badging on the car refers to Ettore Bugatti, the founder of the company, while the '16.4' refers to the 16 cylinders and four turbochargers configuration of the engine. The Bugatti Veyron Super Sport holds the Guinness World Record title for the 'World's Fastest Production Car', though at one point of time the title had been reworked owing to some discrepancy in guidelines. Controversies aside, the Bugatti Veyron is nothing short of an engineering marvel and was the first production car ever to breach the 400kmph mark.

Engine

Bugatti Veyron at Top Speed The engine has been created by joining two V8 blocks, each with a 15 degree bank angle, together in the crankcase. The engine is aspirated by four turbochargers. In its standard form, the engine produces 987bhp and 1250Nm of torque while in the Veyron Super Sport, it churns out 1184bhp and 1500Nm of torque. The power is sent to all four wheels through a permanent all-wheel drive using the Haldex Traction system. The Veyron uses a seven-speed DSG sequential gearbox unit.

Cooling is taken care of by a total of 12 radiators while cross drilled radially vented carbon fibre reinforced silicon carbide composite discs help the car slow down.

Check out this machine running at top speed in this video:

TECHNICAL TERMS OF ENGINEERING METROLOGY !!

1.)Calibration:If a known input is given to the measurement system the output deviates from the given input, the corrections are made in the instrument and then the output is measured. This process is called “Calibration”.

2.)Sensitivity:Sensitivity is the ratio of change in the output signal to the change in the input signal.

3.)Readability:Refers to the ease with which the readings of a measuring instrument can be read.

4.)True size:Theoretical size of a dimension which is free from errors.

5.)Actual size:Size obtained through measurement with permissible error.

6.)Hysteresis:All the energy put into the stressed component when loaded is not recovered upon unloading. so the output of measurement partially depends on input called Hysteresis.

7.)Range:The physical variables that are measured between two values. One is the higher calibration value Hc and the other is Lower value Lc.

8.)Span:The algebraic difference between higher calibration values to lower calibration values.

9.)Resolution:The minimum value of the input signal is required to cause an appreciable change in the output known as resolution.

10.)Dead Zone:It is the largest change in the physical variable to which the measuring instrument does not respond.

11.)Threshold:The minimum value of input signal that is required to make a change or start from zero.

12.)Backlash:The maximum distance through which one part of the instrument is moved without disturbing the other part.

13.)Response Time:The time at which the instrument begins its response for a change in the measured quantity.

14.)Repeatability:The ability of the measuring instrument to repeat the same results during the act measurements for the same quantity is known as repeatability.

15.)Bias:It is a characteristic of a measure or measuring instruments to give indications of the value of a measured quantity for which the average value differs from true value.