Difference between 2 stroke and 4 stroke engine

The movement of the crankshaft and piston is what distinguishes the two-stroke and four-stroke engine cycles.

The primary distinction between a 4-stroke engine and a 2-stroke engine is the number of stages or complete revolutions required to complete one power stroke. A 4-stroke engine requires four stages or two entire revolutions, whereas a 2-stroke engine only requires two stages or one complete revolution.

2 Stroke Engine

1) 2 Stroke engine is lighter in weight.

2) Cost of two stroke engine is less as compared to four stroke engine.

3) Motorcycles, scooters etc uses 2 stroke engine.

4) It consumes more lubricating oil.

5) This is air cooled engine.

6)Because there is less friction between theparts in a two-stroke engine, the mechanical efficiency is greater.

7) It consists of two ports inlet and outlet ports.

8) It produces more smoke.

9) Maintenance cost is less.

10) Compare to four stroke, starting the engine in 2 stroke is easy.

4 Stroke Engine

1) It is heavier.

2) It’s cost is high.

3) It is used in bus, truck, car etc.

4) Consumes less lubricating oil.

5) Both water or air can be used for cooling an engine.

6) In 4 stroke engine mechanical efficiency is less because it has more friction in parts.

7) In four stroke engine, there are inlet and exhaust valves.

8) It produces less smoke.

9) Because there are more parts in 4 Stroke engine , the maintenance cost is more.

10) Here in four stroke starting the engine is not easy.

Difference between spark ignition (SI) and compression ignition (CI) engine

In mechanical engineering internal combustion engines are basically of two types:

A) Spark ignition (SI) or Petrol engine

B) Compression ignition (CI) or diesel engine

A) Spark ignition (SI) or Petrol engine

1) spark-ignition engine is sometimes known as a petrol engine.
2) Petrol engines are spark-ignited internal combustion engines.
3) They use fuels that are reasonably volatile, like petrol.
4) In these engines, fuel and air are often combined after compression.
5) Petrol engines operate via the Otto cycle, which entails two isochoric and two isentropic processes.

6) Internal combustion engines use two completely distinct mechanical technologies for ignition: spark and compression. Compression ignition (CI) engines and the  petrol engine(SI) engines; both operate similarly and sometimes on the same operational principles.

Note: Diesel is utilised as a fuel in compression ignition (CI) engines while petrol or gasoline is used in spark ignition (SI) engines. Diesel engines are heavy and operate at lower speeds, whereas petrol engines are light and operate at faster speeds.

B) Compression ignition (CI) or diesel engine

1) A compression-ignition engine (CI engine), often known as a diesel engine named after Rudolf Diesel, is an internal combustion engine in which the fuel is ignited by use of the heated air in the cylinder brought about by mechanical compression.
2) Because CI engines have a higher compression ratio than SI engines do, more work is done with each expansion stroke, increasing their thermodynamic efficiency.
3) CI engine works on diesel cycle.
4) Compared to petrol engines (20%), diesel engine has a fairly high efficiency (35–40%) Because of its high compression ratio of about 18.
5) Diesel engines are more difficult to start than petrol engines of comparable design and displacement because of the higher compression ratio and the added weight of the stronger components.

What is Mechanical engineering easy definition?

One of the most diverse engineering fields is mechanical engineering. Engineering mechanics create, develop, construct, and test. They work with anything that moves, including machinery, human bodies, and component parts.

Mechanical Engineering is the field related to tools and machinery, and the use of mechanics in industry.

Mechanical Engineering is the study machines, it’s components, how they work and it’s application.

There are lot of technical Areas where mechanical engineer work. Few of them are design, production, manufacturing, quality etc.

Mechanical Engineering is a brach of engineering which opens lots of options.Some are piping design engineering, Industrial automation etc.

If you have done mechanical engineering from institute like IIT then you get placed in good company with handsome salary.

In one word we can say mechanical engineering is study of machines and it’s applications.

Mechanical engineering mostly consists of physics and mathematics.

Some of the subjects in mechanical engineering are Theory of Machines, Strength of materials,Internal combustion engines etc.

Today we cannot imagine a world without machines.So future scope of mechanical engineering is good. Also now a days electric vehicles are coming in market, there the mechanical engineers can get a job.