Micromashington OP t1_iuj00y9 wrote on October 31, 2022 at 6:14 PM

Reply to comment by Leucippus1 in ELI5: How exactly do we get some much power from engine now, than we did 40, 50, 60 years ago? by Micromashington

Running water for what, cooling?

Leucippus1 t1_iuj1k9l wrote on October 31, 2022 at 6:24 PM

A little history, in piston airplanes of old, they discovered that by injecting some water in with the fuel/air mixture you get a denser charge and more power in the combustion. This is important in high flying pistons where you need a fuel with a lot of octane.

https://www.carthrottle.com/post/water-injection-how-does-it-work/

The other way to do this is with tetryl lead, one of the reasons why engines made big power in 1967 and that engine made terrible power in 1980. We solved all of the issues with making big power with unleaded fuel by using electronics and injection.

Water injection is the one tool we didn't use. We still run lead in AvGas even though we have known for generations that you could use water injection as a substitute for lead.

Micromashington OP t1_iuj8eon wrote on October 31, 2022 at 7:09 PM

Very interesting. Thanks for the info. But if this system is so good, why has it not been a regular things in use for cars?

Leucippus1 t1_iujcysz wrote on October 31, 2022 at 7:40 PM

Wouldn't want to inconvenience anyone by making them fill up with gas AND water.

Similarly, you can eliminate much of the nitric oxide and other damaging chemicals by mixing diesel with a bit of propane. Propane injection has been used by tuners for years to make their diesels go really fast.

https://www.sae.org/publications/technical-papers/content/872095/

So why don't we do that? Well, because it is more convenient to replace diesel exhaust controls (the blue liquid) every 6 months than it is to add propane every fill-up, despite it being a better for the environment and better for the engine.

greatvaluemeeseeks t1_iujeeeu wrote on October 31, 2022 at 7:50 PM

Because it's a other thing to break and if the engine is expecting water and methanol to be injected and it fails to do so you will shoot engine parts out the side of your engine.