Cooking oils also go to high temperatures. Do they expire before a synthetic would?
Edit:
Wasn’t wondering to make a substitute. It’s not an environmental or political question. Just wondering the *why* (:
Thanks so much to everyone who answered!
In: Chemistry
I’m 95% sure ProjectFarm (YT channel) has done this exact test among many other thorough substance/brands-mechanical experiments.
Not all oils are created equal. “Oil” is a broad array of hydrocarbons, and some of them burn differently than others. Shove the wrong kind of oil into an engine, and it’ll either not run at all or will run for a while before breaking (you can’t put gas in a diesel engine, for example). Sure, you can modify car’s engines to run off vegetable oil (and some hobbyist mechanics *do* do that), but then you run into other problems, such as:
* There’s no infrastructure for vegetable oil cars (gas stations, oil refineries, etc.) that there is for gas cars. (With the exception that gas is already supplemented by up to 10% corn ethanol already).
* You have to *grow* the crops that you’re burning in your cars. Viable farmland is already at a premium, and now you want to add fueling cars to it?
* Using crops for fuel will increase the prices of those crops as food.
Now, all of those are solvable, theoretically, except that there’s no economic incentive to do so yet. When crude oil starts really running dry, then maybe we’ll move to grown oils (and my money’s on GMO algae farms over vegetable oil as a renewable fuel source), but for now, convincing the government to ignore the oil industry and invest billions in converting the whole infrastructure over is nigh-impossible.
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Engine oil needs to remain chemically stable at engine operating temperatures, which will routinely exceed 200F and have some areas even hotter than that.
Most food oils aren’t chemically stable under those conditions.
Then there are other concerns with cold viscosity (your oil can’t be frozen!) and lubrication (can’t be too watery!), but first you have to not burn up.
Engine oils are designed to provide lubrication for the engine. Oils are used because of their viscosity. However, temperature effects cause changes in the viscosity of the oil. Low temp = more viscous and high temp = less viscous. Engines are designed to operate with a certain range of viscosity. If the oil is too viscous, it won’t circulate properly, and will reduce lubrication, and gum up the small passages it flow through. If it’s not viscous enough, it won’t provide enough lubrication, and will cause excess engine wear.
So when you see an oil rating like 10w30, this tells you the viscosity rating of the oil at different temperatures. The number is a standard set by ASE, where a lower number is more viscous and a higher number is less viscous. In our example, 10w means the oil will be an ASE 10 viscosity at winter temperatures (32F), hence the W for “winter”. The 30 indicates a viscosity of ASE 30 at high temperature (212F). Different engines are designed for different oil ratings depending on how tight the tolerances of the engine are, how much heat the engine creates, etc.
The problem with plant based oils is that they are way too temperature sensitive, and generally not viscous enough. They are also extremely expensive relative to hydrocarbon based lubricants, and not practical to scale. It just to expensive and hard to spend a year growing a plant to extract 2% of the weight of the plant. So, even if it did work, we don’t have enough farms to make it happen and feed ourselves.
* most vegetable oils can’t withstand the temperatures in a car engine without breaking down
* there isn’t a great need, consumption of motor oil is low compared to gasoline, so it isn’t contributing to pollution and CO2 emissions they same way other fossil fuels do
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