A lot of car enthusiasts hold a special place in their hearts for semi trucks, whether they’re obsessed with big-rig reviews or, like noted car collector Beyonce, singing on top of a Dekotora. When you’ve got it really bad, you might even start wondering what the big spikes on semi-truck wheels are for, or why truck drivers still thump their tires. Well, you obviously came to the right place, and we’re going to extend your knowledge today by letting you know about those chrome tubes — perhaps better described as cylinders or canisters — that are usually mounted outside a semi truck’s engine compartment.
Those aren’t fuel tanks, and they’re not tanks for diesel exhaust fluid or oil or anything like that, either. In fact, they’re not tanks at all. They’re the housings for big rigs’ big air-cleaning systems, including its air filter, which is vital for proper engine breathing to optimize performance and efficiency. Which may have you wondering, if those air filters are so vital, why don’t all semis have them? Well, they do, but some modern big rigs are built with under-hood air filters for better aerodynamics and emissions performance.
How the air filters in those chrome tubes work
Two things are needed for combustion in internal combustion engines: air and fuel. On the air side of the equation, however, we’re really talking about the oxygen in the air around us. Oxygen is the specific element needed to combine with the fuel for burning, and it’s that burning — combustion — that creates the power needed to drive the engine.
You know what’s not needed for combustion? Any kind of dirt, debris, or other contaminants that may be floating around with that oxygen. An air filter’s job is to trap that kind of stuff as it comes through the air intake, allowing only clean air to pass by and keeping harmful materials from getting into the engine. To do that, air filters come in two basic setups: dry or wet.
The first relies on, obviously, dry filter material that often looks like paper or fabric to keep dirt and whatnot from entering the engine. The latter wears an additional thin coating of oil that helps trap even finer particles from passing by. The key real-world difference is that dry filters are meant to be disposable and replaced when they get too dirty, while wet filters can be cleaned and reused.
Signs your air filter is going bad
Whether you’re driving a big rig or a subcompact car, you need to keep a sharp eye on your air filter. After all, a dirty filter can get so clogged that it restricts how much clean air is getting into the engine. Less air coming in then means less oxygen is available for combustion. And the results of that include major reductions in efficiency and performance. Remember, the combustion stroke in a four-stroke engine is where the power is made, so anything that negatively affects combustion will have a negative impact on your engine’s ability to operate.
Filter issues can also cause your exhaust system to produce black smoke since the air/fuel mixture — made up of less air than the engine is designed for — doesn’t burn properly. Another concern is that when the filter gets too dirty, it can stop working and start letting contaminants make their way into the motor. To be exact, those unwanted particles can find their way into the tiny space between the piston head and cylinder wall, eventually leading to overheating and catastrophic engine failure if not addressed. With that in mind, you might even want to check your air filter today.
