Under-the-hood air filtration: Something wrong with this picture?

When I used to do the oil and oil-filter changes on my own car, the commercial establishment where I previously purchased the new replacement oil and oil filters from, also had provisions on site to take both the used, dirty oil and oil filters. I changed the oil filter with each oil change, which was four times a year or every three months on average. I did a lot of driving back then.

Now, as for my vehicle’s air filter, you know, the one located under the hood, the rule of thumb here is that this got replaced when it was dirty enough to warrant replacing. This was determined via direct visual inspection.

The thing with automobile internal combustion engines – the operative word here being “combustion” – in order for combustion to occur, this requires air – air, in other words, is an integral part of this process. In fact, three ingredients, if you will, are required in bringing internal combustion about: air, fuel and compression. When air and fuel are sufficiently compressed the air/fuel duo inside the combustion chamber or cylinder are then ignited. The piston itself, meanwhile, serves as the device that allows for this action. The coordination and cooperation of all cylinders is what enables the generation of power, said power ultimately transformed through mechanical means into rotational energy (read: “the turning of the vehicle’s wheels”). This at least is my understanding of how the process works. An oversimplification, no doubt, but you get the idea.

Like the fuel that acts as a catalyst for combustion, the air used in this process too, is also first filtered. Imagine how much dirtier the combustion process would be if neither the fuel nor air underwent a so-called “pre-scrub.” Pretty filthy, I would imagine.

Which brings me to the next part of today’s discussion – the air that the air filter is filtering.

A lot of stuff can be found in the air. There is oxygen, of course, but there can also be measurable amounts of carbon monoxide, hydrocarbons, oxides of nitrogen, ozone, particulates – these are the main ones. A reason behind a lot of these pollutant emissions being in the air is from the burning of fossil fuels – directly and indirectly. And motor vehicles, through the exhaust system, are a significant contributor of this so-called “stuff.”

So, it seems somewhat incongruous, counterintuitive even, that the up-front, under-the-hood air-filter unit is tasked with blocking some of these emissions, at least partly preventing their getting into the piston chamber. The question, though, is: How good a job does the air filter do at stopping at least a few if not many of the pollutant emissions air has in it?

But another better question might be: Is that really all that important? Reason being, you would think that should these air impurities reach the combustion chamber, the high heat from the combustion process is enough to make harmless the said pollution that made its way to the said chamber in the first place. You would think.

I mean, after all, the fact that combustion is less than 100 percent efficient, well, this is the reason for the harmful particulate, carbon monoxide, oxides of nitrogen, hydrocarbon and smog-forming emissions that are present in vehicle-engine exhaust. Think about it.

Exhaust that in the United States must, by law, be analyzed, at minimum, once every two years in the biennial smog-check review. It’s also the reason for the creation and installation of on-vehicle catalytic converters.

In taking all of this into consideration, wouldn’t it just be smarter, cleaner, healthier all around to just forgo all of this? And, by that, I mean to transition away from internal-combustion processes and switch over to pollution-free electric-vehicle operation? Though the cost to make that transition initially may be higher, in the long run, there is money savings from not needing to purchase liquid or gaseous fuel, reduced vehicle maintenance and no smog checks and possible needed repairs in order to be compliant, that, along with the improved air quality and health resulting from fewer and fewer gas-powered vehicles being on the road. Not to mention that the main air filter of any concern in the vehicle so-outfitted with electric capability, would be the one in the car’s interior used to filter the cabin air. Now that’s what I’m talking about!

– Alan Kandel

All material copyright 2021.

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