MECHANICAL ENGINEERING TERMS 4

MECHANICAL ENGINEERING TERMS:-

1. Spark Plug: -

 A spark plug is a device used in an internal combustion engine that is, an engine that derives its power via exploding gases inside a combustion chamber to ignite the air-fuel mixture.

 Cars typically have four-stroke gasoline engines, which means there are four strokes, or movements, to the moving parts inside the engine per rotation. Inside each cylinder is a piston, which moves up and down within the cylinder to compress the gas for combustion, and pushes the exhaust gases out after combustion. The piston is operated by an arm that attaches to the crankshaft, a shaft that extends through the bottom of the engine. The piston goes up and down twice during each rotation, hence the four strokes -- up, down, up, down. 

The spark plug is positioned at the top of the cylinder, where the air-fuel ratio is compressed. The tip of the plug sits inside the engine, recessed into the side of the cylinder wall. The other end remains outside the engine and is attached to a wire that is also attached to the distributor.

2. Independent Suspension System :- 

When a vehicle is said to have Independent suspension system it means that the suspension system is set up in such a way as to allow the allow the wheels on the left and right side of the vehicle to move vertically independently of each other while driving on uneven surfaces.

This is achieved by not directly connecting the wheels together on the rigid axle.

In this suspension system the unsprung weight of the vehicle is decreased , softer springs are permissible and front - wheel vibration problems are minimized.

3. Supercharger:- 

A supercharger is an air compressor that increases the pressure or density of air supplied to an

internal combustion engine. This gives each intake cycle of the engine more oxygen, letting it burn more fuel and do more work, thus increasing power.

Power for the supercharger can be provided mechanically by means of a belt, gear, shaft, or chain connected to the engine's crankshaft. When power is provided by a turbine powered by exhaust gas, a supercharger is known as a turbo supercharger typically referred to simply as a turbocharger or just turbo

4. Unsprung Weight:- 

Unsprung weight is an important concept.This is the weight of a vehicles components that is not supported by the suspension system of the vehicle.  The Unsprung weight includes wheels , brakes , tyres , the rear axle assembly and other structural members that are not supported by the springs. 

OR

We can say that all the parts outboard from the suspension springs.

In Formula-1 car , we should say semi-sprung rather than unsprung because each tyre acts as a spring in its own in F-1 car

5. Turboprop Engine:-

A turboprop engine is a type of turbine engine which drives an aircraft propeller using a reduction gear. 

The gas turbine is designed specifically for this application, with almost all of its output being used to drive the propeller attached at the front of the engine.

The engine's exhaust gases do not contain enough energy as compared to a jet engine, to create significant thrust in the propulsion of the aircraft.

The propeller is coupled to the turbine through a reduction gear that converts the high RPM, low torque output to low RPM, high torque. 

Because of improvements in turbojet design, the turboprop, which is less efficient at high speeds, lost much of its importance in the 1960s, though it is still used for relatively short-range aircraft.

6. Ramjet Engine :-

A ramjet, sometimes referred to as a flying stovepipe, or an athodyd which is an abbreviation of Aero thermodynamic duct, is a form of airbreathing jet engine using the engine's forward motion to compress incoming air, without a rotary compressor.

Key Points:-

>Ramjets cannot produce thrust at zero airspeed, thus they cannot move an aircraft from a standstill.

>Ramjets can be particularly useful in applications requiring a small and simple mechanism for high- speed use, such as missiles or artillery shells.