quick notes on car engines and subsystems:

gasoline car engines convert gasoline into motion, the easiest way to do so is to burn gasoline inside an engine: internal combustion engine. 

• internal combustion can be with diesel engines or gas turbine engines
• an example of external combustion would be a steam engine
• almost every car w/a gasoline engine uses a 4-stroke combustion style. the core of an engine is the cylinder w/the piston moving up and down inside the cylinder.

4 stroke combustion style:

1. intake stroke: intake valve opens and piston moves down to take in a cylinder full of air and gas
2. compression stroke: the piston moves back up to compress this fuel/air mixture. Compression makes the explosion more powerful. 
3. combustion stroke: when the piston reaches the top of its stroke, the spark plug emits a spark to ignite the gasoline, charge in the cylinder explodes, driving the piston down.
4. exhaust stroke: once the piston hits the bottom of its stroke, the exhaust valve opens and the exhaust leaves the cylinder to go out of the tailpipe. 

in a multi- cylinder engine, the cylinders usually are arranged in one of three ways: inline, v, or flat (also known as horizontally opposed or boxer).

quick parts/vocab:

spark plug: supplies spark that ignites the air/fuel mixture

valves: intake and exhaust valves open at the proper time to let in air and fuel while also letting out exhaust. both remain closed during compression and combustion. 

piston: a cylindrical piece of metal that moves up and down inside the cylinder.

piston rings: provides a sliding seal between outer edge of piston and inner edge of cylinder, serving two purposes: preventing fuel/air mixture and exhaust from leaking into sump, and keep oil in the sump from leaking into the combustion area. 

connecting rod: connects the piston to the crankshaft and can rotate at both ends so the angle can change as the piston moves and the crankshaft rotates. 

crankshaft: turns piston's up and down motion into a curricular motion. 

sump: surrounds the crankshaft contains some amount of oil, which collects in the bottom of the sump (oil pan).

engine subsystems:

valve train: consists of values and a mechanism that opens and closes them. the opening and closing system is called a camshaft. most modern engines have what's called overhead cams, which mean the crankshaft located above the valves. older engines are located in the sump near the crankshaft. 

timing belt: links the crankshaft to the crankshaft so that the valves are in sync w/the pistons. the camshaft is geared to turn at half the rate of the crankshaft. many high performance engines have 4 valves per cylinder (2 intake, 2 exhaust) and this arrangement requires 2 camshafts per bank of cylinders (dual overhead cams). 

ignition system: produces a high-voltage electrical charge and transmits it to the spark plug via ignition wires. the charge first flows to a distributor, which you can easily find under the hood of most cars. the distributor has one wire going in the center and four, six, eight wires (depending on the # of cylinders) coming out of it. these ignition wires send the charge to each spark plug. the engine is timed so only one cylinder receives a spark from the distributor at a time.