Difference in Internal Combustion in Engines (2 Stroke Engines and 4 Stroke Engines)

Hello, I welcome you to my blog today and I have something I would love to share with everyone who might be opportune to see this post.

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First I would love to ask;

_{Do you know the working principle (internal combustion) of the engine in the car and working principle in the generators are different?}

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Yes they are different but when u say generator there are many factors attached to it Because some of the generators we use in the industries and warehouse even in some estate have the working principles of a car or vehicle engine.

There are 2 different cycles in which an engines can work and they are the

• 2 Stroke cycle
• 4 Stroke cycle

When I said engine cycle I meant the stages it will pass through before the engine starts to work and it's continues in cycles just like that.

Introduction

A machine that have different moving parts or element that transforms power into motion is called an engine. On this article I would focus in the process of conversation of power and how the power was generated which is the working principle (internal combustion) of the machine and I would not be going into the motion part and probably I would do that some other time.

Like I said earlier the engine and combustion process in a generator system (a small one at that), motor cycle, tricycle etc. is different from the engine in the vehicles. Before I start the different and explain them I would like to say what engine cycle is. Before the machine of any automobile starts to work there is ignition of the engine that starts from the taking in it the fuel to the compression of the fuel and then to the powering of the engine and then the exhaust where the burnt fuels is been disposed from. All the stages are in stoke, that is where the difference come in.

Engine cycle can be in 2 or 4 stroke and the 2 stroke are in the generator system (a small one at that) While the 4 stroke happens in the vehicles and bigger generator set.

The process of the engine ignition cycle are below:

• Intake stroke
• Compression stroke
• Power stroke
• Exhaust stroke

Explanation is how the 4 stroke engine works

Typical example of a 4 Stroke engine (Vehicle engine)_{image source (pixabay) CC0 Licensed}

As the name 4 Stroke engine, it implies that the internal combustion is completed in 4 Stroke while the crankshaft is been turned twice.

A stroke refers to the full travel of the piston along the cylinder, in either direction._source

The process completes within a 720 degrees rotation of the crankshaft which is going 360 twice that makes a cycle. a thermo cycle is a series of thermo process and after the process the system returns back it initial state meaning the thermodynamics process happens during the stroke._source

gif of the cycle from intake to exhaust

The gif shows that a cycle is completed when the four strokes which are intake, compression, power and exhaust is completed. After the the cycle is completed the crankshafts rotates which brings about the movement of the the car and I have said I won't be talking on the movement but the process that brings the movement. There are parts of the engine that can make the 4 stroke engine work perfectly which are the piston, connecting rod, crankshaft, spark plug, flywheel and most importantly the inlets and outlet valves.

The Strokes explained below:

(1) Intake stroke:
At the stage the inlet valve opens for the fuel to come into the cylinder for combustion or it can be said to be a suction stage where the fuel is sucked in.

note: When the inlet valve is opens for suction the outlet valve which is the the exhaust is closed and this is achieved when the crankshaft rotates 180 degrees

For the fuel to come in the piston will have to move downward as it is in the gif above in other to suck the air-fuel mixture through the intake valve. The actual engineering term for the movement from the top of the cylinder to the bottom of the cylinder is saying the piston moves from the top dead center to bottom dead center.

After that stroke it is the compression stroke

(2) Compression stroke:
From the intake stroke where the air and fuel mixture is been taken in and the piston has to move from top dead center to bottom dead center to make an opening for the air and fuel mixture to go in.
Now in the compression stroke the fuels and air is been compressed as the name implies whereby the piston moves again from bottom dead center to the top dead center with the help of the momentum on of the flywheel to compress the mixture of air and fuel and in this case the inlet and outlet valves are been closed for the combustion to take place and the crankshaft must have rotated a complete 360 degrees Because for the most piston to move to the top dead center the crankshaft has to rotate another 180 degrees which makes it 360 degrees.

(3) Power stroke:
At this stage of the cycle while the inlet and outlet valve are closed there is going to be a spark on the spark plug to start the engine and here the piston rotate another 180 degrees that amounts to a total rotation of 540 degrees.
In this stage there is an expansion in the air and fuel mixture that is ignited with the help of the spark plug and this stroke is responsible for the mechanical work for the crankshaft.

And the final stroke of a 4 stroke engine
(4) Exhaust stroke:
At the final stage of the cycle which is the exhaust stroke, the inlet value remains close and the outlet value opens with the help of the flywheel momentum in other to move the piston form the bottom dead center to the top dead center in a way of pushing the waste out in form of gases through the outlet value and at this stage the crankshaft make another rotation of 180 degrees which all together from the first stroke to the last stroke is 720 degrees.

Explanation is how the 2 stroke engine works

Typical example of a 2 Stroke engine (bike engine)_{image source (pixabay) CC0 Licensed}

In this type of engine the cycle is completed in 2strokes i.e all the internal combustion is completed in 2 strokes which is like in the 4 Stroke engine whereby the engine take 4 stroke to ignite and give out waste.

note: Same process from the taking in of the air and fuel mixture down to the exhaust stroke happens in the 2 stroke engine but it happens in 2 strokes on like the 4 Stroke engine that is that completes in 4 strokes

gif of the 2stroke engine cycle from intake to exhaust

The gif shows how the 2stroke engine works and it's had come some engine elements in place to complete this process which are piston, connecting rod, crankshaft, flywheel, spark plugs, counter weight and most importantly the inlet and outlet valve.
In this case it's going to be just

• Downstroke
• Upstroke

The strokes explained below:

(1) Downstroke:
Here the only process that occurs here is just the sucking of the air and fuel mixture into the cylinder and it is achieve when the piston moves form the top dead center to the bottom dead center and the crankshaft rotate just 180 degrees.

(2) Upstroke:
At the stage the remaining of the internal combustion process happens starting from the Piston moving back to the top dead center from the bottom dead center for compression of the air and fuel mixture and at that same time the spark plug is fired for ignition and when the air and fuel mixture expands the piston moves down from the top dead center to the bottom dead center also the waste gas is been given off through the outlet valve. At this stage the crankshaft rotation is 360 degrees.

When the piston gets to the bottom dead center the inlet valve opens again and the mixture of air and fuel get sucked into the cylinder.

when the air and fuel was pushed up by the piston for combustion during the first up stroke, a partial vacuum is created as no mixture is left behind in the cylinder._source

The mixture left behind is set for combustion in the cylinder during the downstroke but remains in the crankcase till the piston goes to the top dead center. During the second downstroke, the exhaust gasses is given off from the outlet Value and a new mixture of air and fuel enters the cylinder for combustion after the removal of the previous waste gases. My point exactly is that both happens at same time i.e two strokes are completed with one power cycle.

Conclusion

The internal combustion of engines are different with the combustion cycle but the have same principles. So you might have seen a small generator set and a big generator with same fuel which is petrol and they both are converting mechanical work to electrical energy but they have different internal combustion. The internal combustion of a bigger generator set is 4 Stroke and for some little generators are 2 stroke.

References

• _{Reference 1}
• _{Reference 2}
• _{Reference 3}
• _{Reference 4}
• _{Reference 5}

Thanks for reading