> It doesn't sound expensive to add water injection to an internal combustion engine, until you have to make it work in production, with end users.
Water / methanol injection was commonly used on various piston engine aircraft in the 1940's. It had several benefits, cooling the input air, preventing pre-detonation at high compression (due to lower octane fuel in some cases), lowering the combustion temperature, and such. It was practical and worked fine for high-performance aircraft, that saw regular maintenance after every flight.
It doesn't seem very necessary or practical for a ground vehicle though.
Yeah, water/meth injection is pretty common mod for forced induction cars to squeeze some more air in there without causing detonation. People often just tap the windshield washer reservoir and use that to hold the meth, since windshield wiper fluid is a more diluted methanol mix you can still use it for your windshield. I personally don't run it because running out of meth on a vehicle that is tuned for it can have disastrous consequences.
It _is_ practical for cars, but a similar technology is easier and better: Exhaust Gas Recirculation.
The problem of water injection is engine corrosion and system maintenance. EGR further improves the exhaust gas composition by burning the CO and similar not fully oxidized parts. The main effect is the same, i.e. providing some inert material that expands after detonation using up the heat.
Water / methanol injection was commonly used on various piston engine aircraft in the 1940's. It had several benefits, cooling the input air, preventing pre-detonation at high compression (due to lower octane fuel in some cases), lowering the combustion temperature, and such. It was practical and worked fine for high-performance aircraft, that saw regular maintenance after every flight.
It doesn't seem very necessary or practical for a ground vehicle though.