water injection = Higher Efficiency?

[t vago]

Originally Posted by bazman

Guys - though we appreciate the science - it'd be more useful to discuss what might work in a car on the road.

Let's get back to that. This thread has potential if we make this all real.

Again - has anyone played with timing and lean burn while injecting high pressure water/meth?

I've never found anyone that has yet. I've come across meaningless experiments, and those that have tried injecting straight water without a custom tune hoping the water would do something magical. But who has actually tuned mappable water/meth injection under lean burn conditions?

I don't think anyone here has done so.

Originally Posted by bazman

To me, the obvious thing to do is try it if no one has. My tuner can change my timing and air fuel to anything the engine can take, and the potential lean limits go up if we drop the O2 sensors.

For straight gasoline, maximum fuel economy is seen at an AFR of 17:1.

Originally Posted by bazman

Will the increase be enough to justify the added cost of the meth? Hopefully. Would the increase justify the cost of the injection setup itself? likely not - but if you run boost then that cost is justified for other reasons.

Cost? If the water injection setup could be done cheaply enough, then it'll still be an attractive option.

It would help to quantify the fuel economy gains for this mod. If, for instance, the modification resulted in a 10% gain in fuel economy for my truck with a 19 MPG baseline, and my driving style (120 mile commute using mostly highway driving), I would consider it to be worthwhile.

Then again, for somebody who gets 30+ MPG, it might not be so attractive.

Originally Posted by bazman

I believe a 50/50 mix of water/meth MIGHT help and for me it is easy as I run that mix anyway and have a sizable tank in the trunk to store it. All I need is another water injection kit to supplement the one I have (or replace it if I can vary the flow from very low at cruise to very high at boost). I'd never run water all the time, only under boost or under lean burn conditions. My tune kicks lean burn in after 7-8 seconds of steady light throttle cruise, then off if I poke the throttle.

It definitely would help, but the key is to have an engine tune that takes advantage of water injection. The idea is the same as for boosted applications.

The trick is, as you have pointed out, how to vary the flow. I am assuming that you'd use a water pump variable controller to do this. Fuel injectors are reported to quickly corrode, except for those injectors with stainless steel internals.

Many years ago, when I was planning to install a turbocharger into my Sebring, I had bought a water injection kit, along with numerous solenoid valves and different sized water injection nozzles. Each nozzle was sized to allow roughly twice as much flow as the next smaller one. I was going to design a circuit that would have switched these nozzles on and off such that the engine under boost would have received roughly the same amount of water per cylinder for any given engine speed.

[drmiller100]

Originally Posted by t vago

For straight gasoline, maximum fuel economy is seen at an AFR of 17:1.


.

Wowsers.

The above statement is probably true under certain conditions, but many more examples abound where it is untrue.

Unfounded statements such as this demonstrate lack of knowledge of an internal combustion process with gasoline engines.

[drmiller100]

Mort, I keep going back and reading your post and gleening more information from it.

Again, thank you.

How about we supercool exhaust gasses, and regulate these to limit power instead of a throttle plate?

The idea would be for "idle", we inject relatively cold inert gasses into the intake to limit oxygen.

The colder the intake charge, given atmospheric pressures, the more efficient the process, right?

[t vago]

Originally Posted by drmiller100

Wowsers.

The above statement is probably true under certain conditions, but many more examples abound where it is untrue.

Thanks, but I'll take this book, The Internal-combustion Engine in Theory and Practice: Combustion, fuels, materials, design, at face value.

Originally Posted by drmiller100

Unfounded statements such as this demonstrate lack of knowledge of an internal combustion process with gasoline engines.

Other indicators of a lack of knowledge of the internal combustion process? An inability to specify a temperature range for peak combustion temperature. An inability to specify peak compression pressures. Shall we continue?

[bazman]

Originally Posted by t vago

I don't think anyone here has done so.



For straight gasoline, maximum fuel economy is seen at an AFR of 17:1.



Cost? If the water injection setup could be done cheaply enough, then it'll still be an attractive option.

It would help to quantify the fuel economy gains for this mod. If, for instance, the modification resulted in a 10% gain in fuel economy for my truck with a 19 MPG baseline, and my driving style (120 mile commute using mostly highway driving), I would consider it to be worthwhile.

Then again, for somebody who gets 30+ MPG, it might not be so attractive.



It definitely would help, but the key is to have an engine tune that takes advantage of water injection. The idea is the same as for boosted applications.

The trick is, as you have pointed out, how to vary the flow. I am assuming that you'd use a water pump variable controller to do this. Fuel injectors are reported to quickly corrode, except for those injectors with stainless steel internals.

Many years ago, when I was planning to install a turbocharger into my Sebring, I had bought a water injection kit, along with numerous solenoid valves and different sized water injection nozzles. Each nozzle was sized to allow roughly twice as much flow as the next smaller one. I was going to design a circuit that would have switched these nozzles on and off such that the engine under boost would have received roughly the same amount of water per cylinder for any given engine speed.

Thank you for your informative and intelligent response.

I'm going to look at various kits including the ERL Aquamist (ran them before and they work great), Devils Own, Snows and some new ones I've not heard of before like Hydramist that uses Aquamist components. There is also this one that uses a mechanical pump to force the water to atomize rather than an electric high pressure pump...

[drmiller100]

Originally Posted by bazman

I'm going to look at various kits including the ERL Aquamist (ran them before and they work great), Devils Own, Snows and some new ones I've not heard of before like Hydramist that uses Aquamist components. There is also this one that uses a mechanical pump to force the water to atomize rather than an electric high pressure pump...

One idea I've been contemplating.

use a diaphragm pump to pump water to 50 psi or so. Run the line through copper, then heat it off the exhaust so the temps get up somewhere near 250 degrees or so.

then run it through a fuel injector, and inject it under the throttle body.

Piggy back the fuel injector off the main throttle body fuel injector so the pulse width is the same as the fuel injectors pulse width.

The idea is the water would follow fuel flows, which obviously is a pretty good indication of engine loads.

The higher temperature of the injected water means when the water hit the intake manifold it would pretty well atomize - you would not get pure "steam" per se, but you SHOULD get pretty good atomization, just like the fuel gets atomized by the injector pretty well.

[t vago]

Originally Posted by bazman

Thank you for your informative and intelligent response.

No problem.

Originally Posted by bazman

I'm going to look at various kits including the ERL Aquamist (ran them before and they work great), Devils Own, Snows and some new ones I've not heard of before like Hydramist that uses Aquamist components. There is also this one that uses a mechanical pump to force the water to atomize rather than an electric high pressure pump...

Hm... A mechanical pump... (I'm assuming a positive displacement pump, since them electric pumps use impellers)... Now, that's an idea.

You're making me wonder, too, now... I still have those pieces parts sitting in my garage. Perhaps, if I modified my WBO2 gauge electronics to modify the narrowband output to fool my engine computer, then have it come online while I sprayed water in while at cruise...

[bazman]

I need 5 posts to post links so next post I should be able to

[drmiller100]

Originally Posted by t vago

Thanks, but I'll take this book, The Internal-combustion Engine in Theory and Practice: Combustion, fuels, materials, design, at face value.

the book was written in 1968, with an update in 1985 by MIT in places.

I scanned through it - pretty good basics, but does not address lean burn, combustion chamber design, advanced fuel injection, etc.

And I could see no reference where the author stated 17:1 is max efficiency in all cases. In fact, the book seems devoted to describing all the different variables which change effiiciency, flame propagations, etc. and how they interrelate.

Could you point me to the page which says 17:1 is the max efficiency in all cases?

Regards
Doug

[bazman]

This guy uses colorful language at times and does not speak well of his competition, that aside he is allegedly a qualified mechanical engineer not just a mechanic... he uses a mechanical pump and his Rotarys make a lot of power with his water injection...

Water Injection

and here is a you tube of one working - seems to spray a really nice pattern

http://www.youtube.com/watch?v=8Lizxy3XIY8