usually when reading about cars im told that this next generation model has vents that allow for better cooling of the engine which leads to better performance, im wondering why cooling some machinery allows it to preform better and if this is a universal thing or if some things run better when hot
In: Engineering
Lets be super clear. A car engine is basically a container for thousands of explosions per second. The engine creates the conditions for those explosions, triggers them, then uses the energy that the explosions generate to propel the vehicle.
But heat, heat is a problem. Explosions generate heat and some heat is OK but to much will cause the metal in the engine to fuse together. This prevents the parts that we need to move from moving. Parts that are supposed to move but are actually melted together is very bad for an engine.
Heat also causes things to change size, this can cause parts to become jammed. This again causes parts that are supposed to move to not move and that’s bad.
The inherent problem with engines is that the explosions they are designed to contain also generate heat that can cause damage to the engine causing it to stop functioning.
So we need to add a whole bunch of parts and equipment that prevent this heat problem.
First we use oil. Oil is used anyplace that moving metal parts touch one another. This reduces the heat generated by the friction of those parts touching and moving. Without the oil the moving parts of the engine would eventually generate enough friction related heat to fuse them together without any explosion heat required. So when you include the heat from the explosions we need to be super careful about other heat sources like friction. So we use oil all over the inside of engine. Because we need the oil to always be all over the engine there are parts in an engine that distribute the oil, pump and oil and spray the oil.
For the most part the oil stays inside the engine (at least, it’s suposed to). For some cars the oil ends up getting too hot. So we need to pass it through a radiator known as an oil cooler. An oil cooler passes the oil through a series of pipes and blows air over those pipes. The oil goes in one end hot and comes out cooler. That’s mostly for higher performance cars, more normal cars don’t get the oil hot enough to require a seperate cooler.
Oil helps prevent heat from getting generated by friction but it dosent really do anything with the heat that the explosions are themselves generating. We need to do something with that heat because if we don’t we will run into issues.
So cars mostly use coolant. In the olden days this was just water but in modern cars we use a liquid designed for just this use and it does a better job that water alone.
Coolant is just a liquid and often it comes in a fun color (don’t drink it, it’s poison). Coolant gets circulated around the engine by a pump. The coolant gets pumped all over the inside of the engine through tiny pipes that are carved into the solid metal of the engine. It goes all around the engine and absorbs heat. It then takes that heat outside of the engine and passes through a radiator. Just like an oil cooler a radiator blows air over the pipes containing hot coolant and cools the coolant down. So it enters one end super hot and leaves the other end cooled down. It then cycles through the engine all over again getting hot and cooling down in the radiator, over and over and over.
So radiators and oil coolers (and intercooler on turbo cars) all take heat away from the engine, pass cool air over it and cool it down. But under the hood of a car is still a VERY hot place. The vents you ask about help with that part of the cooling process by allowing more fresh cool outside air to get into the engine area or by allowing hot nasty air to escape out of the engine area.
And to be clear. Cooler engines do not themselves perform better. It’s that higher performing engines generate more heat, and therefore require more cooling. The heat limitations of higher performing engines are basically the same as lower performing ones to preventing them from hitting that threshold is more difficult. Basically high performing engines generate more heat but can’t handle more heat, so they require more cooling. Better cooling allows for higher performance engines to exist without hitting that point where they break.
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