Here is BMW, adding Water Injection to increase horsepower and reduce exhaust temperatures.
Done right, with addition of Brown’s Gas (HyZor Technology), you get a major boost in fuel efficiency along with the boost in power. The BG actually turns some of the water into fuel, at the same time as helping the carbon-fuel burn more efficiently with a catalytic action.
I do not know if BMW has a feedback loop, which increases water injection when an exhaust temperature rise is detected, but that’d be a good thing to do. Make a ‘threshold point’ above which additional water is added, and as temperature continues to rise, more water is added; then as temperature drops, less water is added. This would be in addition to the ‘base’ water injected in ratio to fuel consumption.
If you have a turbocharged engine, it is easy to add both water injection and cold fuel vaporization (both as a mist) using HyCO 2DT technology.
Works with Methane (NG), Propane, Gasoline and Diesel engines.
Works automatically because it is turbocharger activated.
Low cost Water Vapor Injection (instructables).