Those familiar with water injection systems used on engines with forced induction know that the systems are plagued with problems. Unreliability, excessive water consumption, uneven delivery, even damage to the turbocharger and engine can occur.
The need for a high degree of atomization and very even delivery that varies with engine load have turned water injection into an exotic alternative to conventional intercooling.
All current, widely available systems, rely on a combination of high pressure feed pumps, small aperture nozzles and electronic regulation to achieve a rather compromised on/off delivery of the cooling charge.
What if there was simpler and more elegant alternative that eliminated the need for an electric pump and allowed for a pattern of delivery that was progressive with engine load?
The answer is a system built around the use of gas/liquid nozzles that are widely used to produce very fine mists in industrial processes and that you may have seen in the vegetable section of your local supermarket. Using a relatively low pressure of gas and water feed these nozzles produce ultra fine mists without the need for small apertures. The air pressure also functions to open the valve, allowing them to stand alone without additional regulation. In addition to pressure/pressure designs, there are also hybrid nozzles that can siphon feed drawing liquid that is below the level of the nozzle and unpressurized.
The source of pressure is intuitive, on the outlet of the compressor turbine we have a pressurized gas source which will feed and regulate the rate of flow, and while the there are no nozzles with perfectly linear pressure/flow relationships proper nozzle and restriction tuning should allow for a far superior match than the "one size fits all" approach that predominates. The degree of watering may also be regulated by placing a pulse width modulated valve in the boost pressure feed line. Once installed, the only other fitting required is the mounting and plumbing of a water reservoir and gauge. To confirm system functionality a low restriction flow switch could be added to the water feed line.-- WcW, Jun 26 2014 Water injected mocking bird http://olanthornton...ird-in-the-rain.jpg [normzone, Jun 26 2014] Crower six-stroke engine http://www.autoweek...0227/free/302270007 [ytk, Jun 26 2014] A really good atomization system http://www.popsci.c...uery=January%201976You want to see the article on page 64. It is about an oil burner, but the sprayer can work with other fluids, like water. [Vernon, Jun 27 2014] Maybe category[ vehicle ]for this one?-- cudgel, Jun 26 2014 I do not fully understand the intent, but I know that water injection exists. Hence, you must further justify your idea or risk mocking.-- normzone, Jun 26 2014 You mean like the Crower six-stroke engine?-- ytk, Jun 26 2014 Water injection comes in two primary forms: Newer pump and nozzle systems often with a fuel injection like spray valve. Either a crappy on/off or something expensive like a PWM nozzle.
The other form is more akin to a carburetor, less mechanical, but still basically crap in terms of water delivery when you need it.
If you don't have an intercooler then the best place to spray your water is right before the turbine, where the increase in air density will make the turbine more efficient. In this way you may also take advantage of the pressure differential across the turbine to power the water injection system.
Mock away, this is a good idea, but it's not going to make sense to anyone who doesn't understand the application.-- WcW, Jun 26 2014 Nothing like any sort of other engine, this is water injection for charge cooling only, and only where water may be injected before the compressor.-- WcW, Jun 26 2014 Maybe I'm not understanding what you're trying to do here, but when you inject water into a hot cylinder it turns to steam and expands, rapidly increasing the pressure. If you want it to, great, it's a power stroke. If you didn't want to, it's essentially the same as a premature detonation.
The concept of injecting water into an engine is the basis of the Crower six-stroke. You have a regular four-stroke cycle, plus an extra power and exhaust strokes where water is injected instead of gas. The steam expands and creates an extra power stroke, and also sucks up heat so you don't need to cool the engine. See link.-- ytk, Jun 26 2014 Well, this idea has nothing to do with injecting water into the cylinder and it does not achieve the same affect. We are misting the water into the throat of a turbocharger to reduce the charge temperature and increase the density of the charge.-- WcW, Jun 27 2014 Oh. Of course.-- ytk, Jun 27 2014 When I posted my comment above the only thing you had loaded in here was the title and the summary.
(marked-for-tagline) " this is a good idea, but it's not going to make sense to anyone "
Too bad that I will require a turbo to benefit from this. I'd like to feed my machines a little water in their diet, but since I started driving modern vehicles the fuel system is not as readily modifiable as it used to be.-- normzone, Jun 27 2014 The subject is pretty foreign to me, but the actual idea is to replace an electric or mechanical pump, for a post-intercooler water-injection system, with one that runs from bleed air ?
Isn't bleed air, by definition, lower pressure than the through ?-- FlyingToaster, Jun 27 2014 No this system can really only be used where water may be injected before the compressor with no other charge cooling, essentially replacing an intercooler entirely. The pressure relationship is between the light vacuum on the intake side of compressor and the .5-1.5 bar pressure on the other side. The higher the relative pressure the more water is aspirated, above a threshold pressure below which little heating occurs anyway.-- WcW, Jun 28 2014 Also (marked-for-tagline) " You want to see the article on page 64 ".-- normzone, Jun 28 2014 random, halfbakery