A car engine basically has thousands of mini explosions happening inside of it, is has parts moving very fast and generating tons of heat, and experiences extreme temperature fluctuations on a daily basis. Yet it is the part that usually dies last in a car.
How do they make them last so long and why are we unable to make other parts of the car as long lasting, such as tires and brakes?
In: 638
Really it boils down to incredible advances over the last ~50 years in:
* Oil quality
* Metallurgy
* Machining
* Control
Oil is just… oil to most people. Buy the cheapest stuff, match the numbers up to the cap, and let ‘er rip. But there are *so* many things that make oil good or bad at its job. The ability to withstand temperature. The ability to flow when cold. The ability to absorb pollutants and contaminants and still function. The ability to not break down over time or mileage. The ability to resist shearing forces at high RPM.
In the past oil was basically just crude pulled out of the ground, plus some chemicals and additives. Nowadays oil is incredibly highly engineered, to the point that Ye Olde Castrol GTX today is of higher quality than almost any oil in the 70s. We always hear “change your oil at 3,000 miles”, because when that phrase was coined that’s all the longer it lasted. It would start to break down and cause more problems than it started. Now, changing it at anything less than 5,000 is just throwing your money away; most oils last 7000-10000 miles.
Metallurgy is one of the lesser talked-about subjects, but it is also hugely important. In the past, cast-iron blocks and heads were the norm. Iron is a fine material, but in the past it was prone to irregular heat expansion and weak spots that couldn’t necessarily be detected by normal factory processes. We still use iron blocks, but our understanding of the casting process has gotten much better and we can better control these variables, resulting in a stronger block.
We’ve also generally gone to aluminum blocks and heads (in passenger vehicles, in any case), which is lighter but weaker; working with specific alloys over the years has resulted in a remarkably strong, light block.
Machining is probably one of the biggest ones. The advent of CNC machining allowed us to take parts that used to have tolerances of .01″ to .003″. It’s an order of magnitude closer together in places like rod ends, crankshafts, and other moving/rotating parts. The less you allow moving parts to move against each other (like a rod bearing against a crankshaft), the longer the engine will last. This also applies to cylinder clearance and other areas.
The last is control. In the past, controlling internal engine operation consisted almost entirely of rotating the distributor, and changing the jets in your carbs. I’m sure you’ve heard the old warning against letting your engine idle for long periods because it’ll cause build-up in your valves. It’s absolute bupkus now.
The computer (ECU) controls tens of *thousands* of parameters, several hundred times a second. It can control spark timing individually, it can control fuel injector flow-both pulse width and strength, it can control coolant flow throughout the engine, it can vary camshaft timing on the fly, and so much more. Every single cylinder, every single revolution, is precisely controlled to deliver exactly the power required – and most importantly, the ECU *will not* allow the engine to get to a place where it will be damaged. Many ECUs, if the temperature gets too high, will deactivate cylinders to manage temps, and heavily restrict the power (and therefore heat) the engine can generate. Really, just enough to limp home – thus the name.
So yeah that’s the gist of it. We’ve engineered the shit out of them, systematically identifying weaknesses and failure points and solving (or avoiding them). It wasn’t any one big innovation that did it – just years and years of continuous process improvement.
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