exhaust

Exhaust

Modern automobiles work based off of a simple, controlled explosion that happens within the engine when an air/fuel mixture is squirted into an airtight chamber and set to explode using the spark plugs. This explosion basically pushes one part of the car (pistons), which pushes or moves other parts of the car, which turns belts and so on an so forth until your wheels are moving…all as a result of the explosion. But there is a principle law of thermodynamics that states that matter can be neither created nor destroyed, so what happened to that air and gasoline mixture that we blew up inside the piston chamber?
Enter the Exhaust

Once the gasoline and air mixture in your car explodes, the carbon in your gas mixes with the oxygen in the air and forms CO2 (or carbon dioxide). Also formed from this process is water (H20) and nitrogen (N2). Nitrogen and water (H20) are harmless to humans and naturally present in our atmosphere in large amounts. The nitrogen atoms created from your car’s engine are small enough to simply slip through the molecular bonds of your car and float free without any effort at all from us. Moving the water vapor and C02, on the other hand requires some work. Both of these are shuttled out of the engine and down a pipe toward the back of your car. Before they reach the end of your car (the tailpipe) they pass through the catalytic converter.
Catalytic Converters

Catalytic converters work as a catalyst - or a facilitator to convert or alter a chemical substance. They do this using extremely expensive components - platinum, palladium, rhodium, or gold (which is the least expensive of the four), and forcing the exhaust from your car through a small, tight honeycomb network of these and other materials, which causes them to change composition and become less harmful before they are passed out of your car’s tailpipe. In addition, the exhaust system of all modern cars has a sensor before the catalytic converter (closer to the engine), which measures the gasses coming from the engine and can notify the computer controlling the engine what the fuel or oxygen ratio is at that point. If the oxygen is too high, the engine can use a lower-oxygen ratio in the combustion to drive the car and vice versa for fuel. This enables modern engines to act at a much more efficient, fuel-saving and emissions-reducing level than was possible in early autos. Because of the extremely expensive materials used in catalytic converters, they naturally are fairly expensive to replace if they are damaged or stop functioning properly. Also, catalytic converters work best when they are heated, meaning that when you first start your car, they are doing virtually nothing at all to the exhaust that is passing through it. Modern hybrid vehicles use their batteries to heat the catalytic converter to an appropriate temperature fairly quickly, which makes them more efficient and managing car engine wastes than a standard car in addition to saving on fuel.

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