Saturday, September 3, 2011



Alright, so that’s it for teacher’s day comics, and I’m going back to science comics.

Okay, so I apologize if the post about wheels was even worse than the one about pulleys and axles, but it’s kind of difficult to talk about machinery without complications coming in from somewhere. Obviously, the same thing goes with engines, because there’s all sorts of engines, ranging from homemade to rocket ship engines, so I’ll just focus on car engines here.

Car engines basically convert gasoline to energy. They do this by combusting (that means exploding) the gasoline. This is why the proper name of car engines are internal combustion engines. They explode the gasoline inside the engine and it’s then the energy that comes from the combusted gasoline is transferred to the wheels to move the car.

Hopefully, you haven’t lost track of what’s happening, because it’s going to be more complicated by the next paragraph. So, now we’re going to talk about HOW engines can combust gasoline.

This is the basic structure of a car engine:

Da Car engine

Yeah okay, I know what you’re thinking, and YES that is a basic structure. If we had gone super deep down we would have to talk about all the gears and axles inside the parts.

Alright, so remember the basic idea is the burn the gasoline, and combust it into energy to move the car. Incidentally, even a tiny bit of gasoline’s energy combusted is enough to blast a potato more than 150 metres.But enough about that, let’s see how an engine works.

There are basically 4 parts to this process.

So, in a real car engine, there would be particular parts of the engine that would be moving. An important part is the Piston (M). The piston moves up and down like an elevator but is always stuck in between the 2 coolants (E). Then there is also the Crankshaft (P). The crankshaft is the weirdly shaped thing (not the circle that the ‘P’ arrow is pointing at, that is also part of the crankshaft) and it scoops up gasoline that is inside the oil pan (G) using it’s scooper. (Oh, by the way, the part that the ‘P’ arrow is pointing at is the centre of the crankshaft. The scooper is one end of the crankshaft) So, the scooper, scoops up some gasoline. It then turns 180 degrees. By this time the piston (which is M) would have moved down, so the scooper pours the gasoline onto the pistol, This is known as the intake stroke. (Yes people, that was only the first part)


In, the second part, the focus is more in the area of the pistol. Before we start however, let’s answer a very simple question. Is there air inside the cylinder in between the 2 coolants? If you can’t answer this question, let’s just say that the only place you can’t find air is in space. So let’s ask again, is that space? (Hopefully you said yes) So, at this stage the pistol moves upwards, it also compresses (that means squashing) the air and gasoline together. This will make the explosion in Stage 3 more powerful. This is known as the Compression stage. (This is also the stage where the crankshaft moves another 180 degrees to scoop up more gasoline.)

So, now we move on to the 3rd stage, known as the Combustion stage. At this point, the gasoline and air are super compressed together, and then the spark plug (K) unleashes a small spark. If you really need to know, when you put gasoline, air, and a spark together, there is a BIG explosion (Alright, so it’s not really that big, but in terms of machinery its quite large) It’s so strong that it pushes the pistol down again. Then, there is the final stage, known as the Exhaust stage. At this point, the exhaust valve (J) springs open. (Do you see the spring on the exhaust valve? It uses that to spring itself forward) It lets the energy created through the combustion to move through the Exhaust port (L) where it is moved to the wheels. After that, the crankshaft takes the gasoline it scooped up and pours it into the pistol, where it is pumped up again, and the whole thing repeats. And a car does all of this a 100 times per minute!

You might notice that there are a whole lot of parts that I didn’t talk about, but that’s because they do things like cooling down the engine, I’m going to leave them and save space on my more interesting posts. However, if you didn’t really follow on what we were saying, let’s just say that there is a very important life lesson to be learnt. Don’t put a lighter into a bucket of gasoline. it will end painfully.

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