We might have come across the ads in tv and other media stating as Volkswagen Bluemotion Technologies. This technology for which Volkswagen has exclusively developed for its automobiles was quite impressive. In German 'Volks' means people and 'Wagen' means car. So together, it's called people's car. Similarly the Bluemotion technology also has its meaning. 'Blue' personifies our blue planet Earth and 'Motion' refers to the movement of automobiles.
This technology is based on the theme of using eco friendly measures and ideas to protect and conserve the environment without compromising the performance of automobiles. Therefore it's an important milestone and also a complete set of new innovations for green tomorrow. Many environmental issues like global warming, climatic changes, Ozone depletion, etc are caused due to increased level of carbon emissions from automobiles. 

The Bluemotion technology has been developed by taking all these factors into account and it puts its solution in their automobiles. 

This technology entirely focuses on the following areas such as,
  • Engine with new technology and revised engine mapping to provide minimal carbon emissions.
  • Transmission systems with optimized gear ratios assisted in a perfect way of delivering power seamlessly.
  • The auto start-stop system.
  • Bi-fuel engines using conventional fossil fuels in combination of LPG (Liquified Petroleum Gas) & CNG (Copmressed Natural Gas).
  • Brake energy regeneration.
  • Producing Hybrid and electric automobiles.
  • Using low rolling resistance tyres.
Engine Technology: The newly developed TSI (Turbo and Stratified Injection) & TDI (Turbo Direct Injection) are extremely economical. The fundamental characteristics shared by all TDI engines are high-pressure fuel injection and variable turbine geometry for excellent cylinder charging and an efficient combustion process. At the same time, Volkswagen is increasingly deploying innovative common-rail technology.
Pioneering technology is used in the TSI engines, combining direct petrol injection with a turbocharger or charge compression with both a turbo and a supercharger, enabling them to deliver impressive performance figures and torque and to provide the driver with the full spectrum of driving pleasure despite the smaller engine. The combustion of the petrol is particularly efficient, with the result that the power output of the TSI engines is considerably higher than is the case with conventional, naturally aspirated engines.

Transmission systems: The innovative DSG dual-clutch gearbox from Volkswagen offers previously unattained shifting comfort that lifts what were once well-defined boundaries between automatic and manual transmissions. This is a 6-speed gearbox that combines the sporty character and low fuel consumption of a manual gearbox with the comfort and convenience of an automatic. Another highlight: gear changes are executed without any interruption of the driving power.

The auto-stop system: The Start/Stop system means your car can virtually stop its engine by itself. It works through the clutch, so when you come to a standstill, you just select neutral gear, release the clutch and the engine switches off with a Start/Stop symbol appearing on the dashboard. When you want to move off again you simply dip the clutch, the engine restarts and you can select first gear and pull away. The system can easily be deactivated, if you wish, by a switch within easy reach.

Bi-fuel engines: Bi-Fuel is a so-called hybrid powertrain developed for smaller, popular models (such as the Golf and Golf Plus). This means that you can use a second fuel in addition to the main fuel type: in this case LPG (Liquefied Petroleum Gas). Helping you “drive” down costs while offering unique flexibility at the same time.

Brake energy regeneration: The alternator voltage is increased when slowing down and braking. This increases battery charging and helps the car slow down. The alternator load is then reduced when accelerating to lighten the burden on the engine and cut fuel consumption. It Recovers and uses the energy produced by braking, reducing fuel consumption and emissions.

Hybrid and electric cars: The next concept is to produce new type of hybrid and electric cars. Hybrid cars are fuel economical and eco friendly. The designing of electric cars providing the ease of use of like conventional cars is being carried out.

Low rolling resistance tyres: Low rolling resistance tyres are part of BlueMotion Technologies. They need less engine power to move the car forward, saving fuel and helping to cut emissions, while still offering excellent performance.

Some of the existing models equipped with Bluemotion technology areNew Polo,Passat.Toura,
New Beetle.


At the end of compression stroke the piston is at the top dead center.During 
compression and power stroke both valves are closed.But in exhaust stroke exhaust valve is opened and piston moves from Bottom Dead Center to Top Dead Center.Similarly,in suction stroke intake valve is opened and piston moves from Top Dead Center to Bottom Dead Center.
To maintain high compression ratio, very less space is left on the top of the piston when it is on the top dead centre. 

So when valves open they can actually hit the piston if depression is not there. That cut in picture is called valve relief pocket that prevents valve from hitting piston.



  • Finishing processes that utilize abrasive belts are referred to as polishing.
  • Polishing generates a brushed or lined finish. 


  • Processes that use cloth wheels with compound applied is called buffing.
  • Buffing removes the lines and creates a bright luster finish. The process of buffing generally requires surface refinement polishing prior to buffing.
Polishing by abrasive belts or discs is required to level surfaces, remove scratches, pits, scale and polish the surface enough so the cut buff can remove the polishing lines. The first polishing step should be done with the finest abrasive possible that efficiently removes the welds, levels, or refines the surface imperfections. From that point on, the subsequent process works to remove the first polishing scratch lines.

Buffing is a rotating cloth wheel that is impregnated with fine abrasive compounds, and it produces a bright-luster finish on metal and composites. Buff wheels are impregnated with liquid rouge or a greaseless compound-based matrix of specialized fine abrasive called compound. The compound is sprayed or pressured into the rotating buffing wheel. The buff wheel acts as the carrier of the compound, which ultimately does the surface finishing.


Suppose we have a Chevrolet Spark of 1 litre (998 cc to be exact!) displacement. It has a 4 cylinder engine. So let's see what if we replace it with a single cylinder engine.
Let's do some basic calculations to find out the bore and stroke of this hypothetical engine. Assuming square type of engine ( bore equals stroke) we get bore=stroke=10.9 cm as opposed to original stroke of approx 5.8 cm. ( Assuming stroke of 7.7 cm ) So that is quite a big stroke length! So now let's discuss a few things about this-
  1. With this big stroke, we need longer crankshaft. Longer is the crankshaft lesser is the maximum RPM achieved by the engine. This hampers the power output of engine. Hence the single cylinder will never be able to produce the same power as that of multi cylinder for the same compression ratio. Although some might argue that this will fetch good low end torque, which is true.
  2. Single cylinders are impossible to balance! They will produce vibrations which are difficult to damp. You will definitely not like your car vibrating like a Royal Enfield bullet. Although flywheels and anti vibration mounts will come to the rescue, but mounts ( not flywheels) require periodic maintenance.
  3. You will need to redesign the clutch which was designed to handle smaller bursts of power than a huge single one! Hence the clutch needs to be bigger and stiffer to avoid slipping which will increase clutch pedal effort enormously and break drivers legs. ( Assuming rest remind same). Moreover the transmission gears needs to be reinforced to handle rough shifting. This is not at all good for a nice passenger car!!
  4. Single cylinder engines are difficult to keep cool, since the coolant jacket is far from the centre of combustion chamber and piston centre, overheating is more probable.
  5. You will be burning all the fuel in one cylinder only which was earlier burnt in four chambers. Complete combustion is difficult to achieve. Also higher in-cylinder temperatures will aggravate NOX formation. Your car is less likely to pass pollution checks unless you invest in expensive Cat-cons. Not at all good for a cheap passenger car.
  6. With single cylinder engine your car will start sounding like a oversized Bullet with utterly no respect for refined exhaust note. No one will buy such sounding car.
  7. If at all you plan to turbocharge your engine, it will not be recommended by turbo manufacturers for turbo and engine safety. Such huge single cylinder's exhaust putts are capable to destroy a turbines of perfectly matched turbo. Singles are definitely not turbo friendly.
  8. Now at this point let's assume you successfully replace the engine overcoming all difficulties. Now there will be such engine parts which you have custom made eg- high Flow fuel injectors, fuel pumps, ECU, also including engine Mechanical parts such as big end bearings and small end bearings etc. But these parts are not even remotely available in any spare parts shop if in case you damage any. If Chevrolet makes such engine they will have to face a lot of difficulties in arranging spares for their angry customers.


As the car brakes, the center of gravity causes a torque (like a big wrench turning the car toward its nose) to force the car to its front tires.
The center of gravity of the car wants to keep going forward. The only thing slowing it down is the transfer of force between the road, and the contact patch of the tire on the road.
That force, which the tire makes with the road, is very simplistic...  That force is composed of only two things. The weight pushing down on the tire, and some number that makes up for the stickiness of the tire, and the terrain it is on.  A sticky tire on good pavement, a high number; a normal tire on ice, a low number. 
Since that force on the tire is highly dependant on the weight on that tire, the amount of braking that the tire can do is directly related to the weight imparted on the tire.

As you can see from the above picture, the front tires can see a bit more weight than the rear under hard braking.
the highest braking capabilities are much higher on the front than on the rear, therefore, we must ensure that those brakes are up to the task.
How do we do that?
Well, it all comes back to torque. Torque is just some force that acts over some distance. It is for this reason that you might use a longer bar on a wrench that you are trying to get a stuck bolt out with.
Let's say you are trying to stop a big heavy tractor tire from spinning. Imagine that you put a little brake pad from the front of a bike a few millimeters from the center of the wheel.  It wouldn't do much would it? Then imagine that you put that same brake, with the same pressure, as far from the center as you could.  Imagine that you could actually put it a few meters farther than the tire. In fact, let's go all the way and say that you could put that little brake pad a few skyscrapers away.  That same little brake pad could do a LOT more to stop that tire.  It would be no problem.
This same principle helps us exert the extra force that we now know front wheels can receive. So bigger diameter brakes up front help even-out the pressure required to stop the car. Those higher forces require additional thickness  to transfer those forces through the disk, and into the hub.



  1. Earthing means connecting the dead part(the one which does not carry current under normal condition) to the earth(ground). For example electrical equipment frames etc.
  2. Under fault condition these parts may attain high potential w.r.t earth(ground) so any living being touching these parts will be subjected to potential difference which may result in flow of current of such a value which may prove to be fatal.
So earthing is to ensure safety or protection of electrical equipment and living being by discharging electrical energy to earth (ground).


  1. Grounding means connecting the live part(the one which carry current under normal condition) to the earth (ground) for example neutral of transformer, 3- ph star connection etc.
  2. Grounding is done for protection of power system equipment and to provide a effective return path from the machine to the power source.
  3. During lightening dangerous high voltage can develop in the electrical distribution system wires. Grounding provides a safe return path around the electrical system of your house thus minimizing damage from such occurrences.
Earthing and grounding has a micro difference . So in layman's term we use grounding(earthing) as a common term for both.
Earthing is more common word in commonwealth countries whereas grounding is the word used in North American standards.


We see the words "drop forged" stamped on so many tools -- it makes us wonder what it is! Why do manufacturers want you to know that a tool is drop forged?
Striking a piece of hot metal with a hammer is forging, and blacksmiths have been doing this for centuries. As blacksmiths experimented with new techniques, they learned that complex shapes could be created by hammering metal into a die. The die contains the shape of the finished product. Modern manufacturers use either a falling hammer or a powered hammer to do the hammering (rather than doing it by hand), and usually use dies on both sides of the piece. This is drop forging.

Drop forging is a metal shaping process, the metal to be formed is first heated then shaped by forcing it into the contours of a die, this force can be in excess of 2000 tons. The drop forging process can be performed with the material at various temperatures;
  • >Hot Forging
    During hot forging the metals are heated to above their recrystallization temperature. The main benefit of this hot forging is that work hardening is prevented due to the recrystallization of the metal as it begins to cool.

  • >Cold Forging
    Cold Forging is generally performed with metal at room temperature below the the recrystallization temperature. Cold forging typically work hardens the metal.

The reason why manufacturers want you to know that a tool is drop forged is because this tells you something about the strength and durability of the tool. The other two ways to make a tool would be casting it from molten metal or machining it (cutting material away) from a larger block of metal. The advantage of forging is that it improves the strength of the metal by aligning and stretching the grain structure. A forged part will normally be stronger than a casting or a machined piece.