# How An Engine Works

By: Vincent Crotty

# The Four-Stroke Cycle

One Day, well, just about every day, you are driving (or riding) in your car, until you start to hear noises, and oh no!  you realize you break down, and have no certain knowledge on how to repair your engine in your car. since that's the case, you then turn to this here book for the best answers for your questions!  I hear that you are having trouble with the Four-Stroke Cycle, RPM, Gasoline, Oil, And Cooling!

Step 1: intake:  Inside a cylinder, the piston goes down, sucking air into the cylinder through open intake valves as fuel is injected.

step 2: compression: with all valves closed, the piston rises, compressing the fuel/air mixture. compressing it results in better power and effiency.

step 3: combustion: a spark ignites the compressed fuel and air, which creates  combustion. about half to 3/4 of the combustion is used for the car, were the rest pushes the piston back down.

step 4: exhaust: the piston rises again, pushing the spent combustion through the open exhaust valves.

I Believe that you should at least know what the pistons are in the cylinders.  If not, The piston is a little, round, piece of metal that is connected to a rod, which is connected to the Crankshaft.  As you can see on this diagram on the left, you are looking at one of eight cylinders in a V-8 engine!

So, in order for the engine to even start, you need to send a spark to the spark plugs, and turn the crankshaft to start up the combustion process.

# "RPM"

Have you ever heard somebody say "RPM"? if not, it means how many times the piston is going up and  down, or  "revolutions per second." on your dashboard, there is a guage like the one on the left, that tells the rpm.  with rpm, you take the amount and multiply it by 1,000.  for example:  say the guage was at 3.  if you do the math, 3x 1,000=3,000.  so your engine would be at 3,000 rpm.

" It's funny because I really had no idea what that extra guage was on the dashboard, so that i know about it, that's pretty cool!"

# Gasoline

It's probably best that me and you know about the three numbers you see at a gas station pump. (87, 89, 93)  those three numbers are the Octane Rating.  What that is, is in gas, it's octane rating refers to it's resistance to auto-ignition.  If you are clueless, Auto-ignition occurs when the fuel and air in a cylinder is compressed alone, without any type of spark.  Highly, this can contribute to Engine Knock, and is highly destructive.  In SUV's, or vans,  (which have "high performance engines,") usually have higher compression, which takes higher octane fuel to prevent auto-ignition.

To tie into fuel, the ratio in gas to oxygen an engine needs is about 1:14.  Each cylinder needs fourteen parts of oxygen.

# oil

Motor oil is used to lubricate moving pats, clean, prevent corrision, improve sealing, and cool down the engine by taking away heat from moving parts to stop friction.

Below the piston, rings around the top of the piston head keep oil out of the combustion process while otherwise allowing the cylinder to be lubricated.

Thank you so, so much for choosing my book to get the latest info on how engines work.  so, by now i hope you are back on the road, and learned a thing or two on your car's heart.   And also, hopefully popping up the hood doesn't feel like opening a door to another dimension!