Aaron and Emma

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What is the difference between a 2 stroke and a 4 stroke engine?

Spark plug ignition Intake (oil, air and fuel).

Piston Barrel Cylinder.

Exhaust reed Crank shaft

Step 1 : Design

Spark plug ignition

Intake valve (air and fuel)

Exhasut valve

Piston Barrel Cylinder

Crank shaft

The design of engines applys to how each engine works.

The piston isThe sucked in, piston which pulls is sucked in, air fuel pulls and oil which into the cylair fuel and oil nder, where into the cylthey nder,compress where and theyignite. compress The andspark ignite. The plug causing spark plug the engine causing the engases. gine gases.

It repeats the same It repeats the same process again process again and and again. when the fuel again. when the fuel oil and air are taken oil air are in,and the previous gas-taken sesthe escape, through gasin, previous the exhaust , which ses escape, through carries air through the exhaust rest of the en-, which the gine. carries air through the rest of the engine.

Step 2 : How it works

The difference here is how they work, similar but in a difference. Same as4a 2 stroke the air and fuel are taken in through theit intake valve, strokes difference in working is that takes in the fuel and air, piston compresses , it ignites but then the gases stay there untill the pisthrough intake valve, andout compresses it like the ton compressethe them and pulls the gases of the exaust valve, and this2 stroke. process starts again

Once it ignites it then is sucked back untill the gases created are relased through the exhaust valve and the process starts again .

Timing is a crucial difference, it all releates back to how it works. A 2 stroke engine rotates once, and sparks every 2 resolution, every turn turns before spark.

Step 3: Timing

A 4 stroke engine sparks every 4 resolutions, 4 turns before every spark. which is where it gets its name from. comes back to the difference in timing.

Two stroke enginges dont have their own lubrication system, so this rquires miing the oil in with the fuel.

Step 4: Oil

Four stroke has its own built in lubrication system that allows the oil to move around the engine.

Because a 2 stroke is a simpler design, its made of less materials, and its based in smaller veichles that require alot of power, so the engine weight is far lighter than a 4 stroke engine.

4 stroke is a more complex design and carrys alot more pistons and mechanisms to recreate the same power because of this, it is alot heavier.

Step 5: Weight

Because the materials have to be light and require alot of power with a basic design. The equipment used for them is very cheap. (cheapest of the 2)

Step 6 : Expenses

4 stroke is more complex and requires more equipment, more pistons crankshaft and more materials to produce power. This makes it alot more expensive

Because of all there main differences. They all fit to specific veichles, or more so built for those veichles. 2 strokes are mostly found in scooters Vespa’s boats, spead boats and motor bikes.

Step Step77: Placement

Because of the size, weight and overall expense and power, you would mainly find this in large veichles. Like Cars Busses, Quadbikes and Vans etc.

By Aaron James Pryke & Emma Wrigley