WHY MODERN ENGINES USE FORGED PISTON? CHECK OUT THE ANSWER !!

Now-a-days forged pistons are used by most of high end vehicles.The main characteristic that makes forged pistons excel in high performance applications is strength and durability. 

The high silicon content of cast pistons makes them brittle compared to forged pistons. Silicon gives the metal lubricity and is mixed in the alloy to limit heat expansion. This is primarily the reason why cast pistons require careful handling. 

Mild shock applied to it may cause the material to break. The process of forging compresses the molecules inside the alloy, which results in a denser surface area compared to a cast piston.

The Difference:

The difference between a normal or cast piston and a forged piston is the manufacturing technique. Traditional cast pistons are considered good enough by most engine manufactures when it comes to stock setups, and suffer no drawback in terms of compression and service life. The cast piston is most common on all mass-produced engines, because the casting process of making this type of piston presents a low cost opportunity to the manufacturer.

Forged pistons employ a single lump of billet alloy which is stamped by the use of a die. The shape of the die determines the size and shape of the piston.Forged pistons are also easy to manufacture as there is no need for big, heavy and expensive casting equipment as employed in the manufacture of cast pistons.

How Air Bags Work ?

Air Bags:-

An airbag is a type of vehicle safety device and is an occupant restraint system. The airbag module is designed to inflate extremely rapidly then quickly deflate during a collision or impact with a surface or a rapid sudden deceleration. 

The purpose of the airbag is to provide the occupants a soft cushioning and restraint during a crash event to prevent any impact or impact-caused injuries between the flailing occupant and the interior of the vehicle. The airbag provides an energy absorbing surface between the vehicle's occupant and a steering wheel, instrumental panel, A-B-C- structural body frame pillars, headliner and windshield/windscreen.

There are three parts to an airbag that help to accomplish this feature:

>The bag itself is made of a thin, nylon fabric, which is folded into the steering wheel or dashboard or, more recently, the seat or door.

>The sensor is the device that tells the bag to inflate. Inflation happens when there is a collision force equal to running into a brick wall at 10 to 15 miles per hour (16 to 24 km per hour). A mechanical switch is flipped when there is a mass shift that closes an electrical contact, telling the sensors that a crash has occurred. The sensors receive information from an accelerometer built into a microchip.

>The airbag's inflation system reacts sodium azide (NaN3) with potassium nitrate (KNO3) to produce nitrogen gas. Hot blasts of the nitrogen inflate the airbag.

LAMINAR FLOW Vs.TURBULENT FLOW : DIFFERENCE EXPLAINED !!!

In fluid flows, there are two distinct fluid behaviors experimentally observed. These behaviors were first observed by Sir Osborne Reynolds.We will discuss this in detail in this article.

Laminar Flow

1. The fluid flow in which the adjacent layers of the fluid do not mix with each other and moves parallel to each other, is called laminar flow.
2. In the laminar flow, the fluid layer moves in straight line.
3. The laminar flow always occurs when the fluid flow with low velocity and in small diameter pipes.
4. The fluid flow having Reynolds number less than 2000 is called laminar flow.
5. The fluid flow is very orderly i.e. there is no mixing of adjacent layers of the fluid and they move parallel to each other and also with the walls of the pipe.
6. Shear stress in laminar flow depends only on the viscosity of the fluid and independent of the density.

Turbulent Flow

1. The fluid flow in which the adjacent layers of the fluid cross each other and do not move parallel to each other, is called turbulent flow.
2. In turbulent flow the fluid layers do not moves in straight line. They move randomly in zigzag manner.
3. The turbulent flow occurs when the velocity of the fluid is high and it flows through larger diameter pipes.
4. The fluid flow having Reynolds number greater than 4000 is called turbulent flow.
5. The fluid does not flow in definite order. There is a mixing of different layers and they do not move parallel to each other but crosses each other.
6. The shear stress in turbulent flow depends upon its density.

The difference is summarized in table below.

Hope,you got a clear picture of the difference between the two types of flow.Share this article with your friends.