Turbocharging is about energy recovery... why not recover MORE?

[ricktb]

Just a thought... sounds good in theory but.. If you did manage to wrap the exhaust components in circulated water, maybe the first little bit would boil off into steam, after that the exhaust parts would cool to such a level that the water would not boil and youd be pumpin liquid water into the turbine... trust me water takes a hell of a lot of energy to boil, i think more than would be produced. I think this is why water injection is the best solution, directly into the combustion chamber and at the source of the heat, this way you can also control the exact amount of water to perfectly boil and expand into steam. The water does use some of the heat energy from the combustion to power the car. I think you'll find the exhaust temp to be cooler on this system.

 

[talonsteve25]

H@xtGSX: If you were ever to get anywhere with this you would have to just do it, seems as most people commenting have no creativity or no sense of innovation, there is no thoughts out side of the box and no suggestions to help you move forward its only what they know of now as all that can ever be. People like Einstein, Da vinci, Thomas Edison were ridiculed for ideas that no one believed would work almost similar to this.

Yes maybe this idea wouldn't work in the end but hell whats worse then failure is never trying it to begin with. But what if it did, there is no SOLID proof on this forum so far that proves it not possible. The crude results you've obtained with your pipe and clamp experiment is even promising. Id say go for it, heres a link to a patient for your exact idea already so this might give you some insight if you wanted to pursue this.

Method of utilizing waste heat in turbocharger unit of an internal combustion engine and internal combustion engine arrangement

 

[4g63dreams]

There is also "Dry Steam" which wouldn't leave residual marks on a housing.

But to be honest... Lol The most I understood here was the english used to type all entries. Other than that... Is there a theory 101 I can get through before I get this stuff?

As for what can we use to heat up whatever is used, can we use the heat thats generated by the motor to heat the water?

 

[DSMmonster123]

I have been down this road before and while it's a great idea in theory there are a few things that will work against you. I don't really feel like doing a huge write up that i'd like to do. but basically there are two problems with flashing water to steam inside the manifold.

First is that the energy required to take a water from a liquid state into a gaseous one requires almost double the amount of energy it took to heat the water in the first place, (google vaporization energy). I went through some rough calculations on the energy available in 1 gallon of gas, I'll have to find them for a later post. I ended up working out that there would actually be a 4% increase in the volume of gas through the turbine with a very small amount of water per rev.
it would take 9.5 gallons of water per 1 gallon of gasoline burned to recover all of the heat energy in the exhaust AND what would be wasted through the radiator. thats 100% efficiency to get the 4% increase so in the real world it would be less, far less, this was also calculated assuming constant WOT. you would have to preheat the water by eliminating the block radiator and recovering its energy before injecting into the exhaust.

the second problem is that small, even vaorized water droplets will destroy a turbine wheel if it's constantly bombarded. under boost it can reach speed of 10 to 20,000+ rpm's. much like water can cut through steel in a water jet at those speeds the turbine it toast. the inconel is very fragile like ceramic. to get around this one would have to superheat the steam which would require more energy than available.

I was about to build an experimental system but the two facts above caused me to abandon the project. It is possible but not probable without some high tech testing and systems, high temp injectors, check valves to eliminate backbressure in the cylinder and such.

If you try it most likley you will just reduce the overall temp of the exhaust stream causing more lag and within a few miles destroy your turbine wheel.

its a nice though experiment, nice to see that there are others that think like me, 70% of the energy in gas is wasted as heat, keep thinking there potential to be had.

 

[H@xtGSX]

I have been down this road before and while it's a great idea in theory there are a few things that will work against you. I don't really feel like doing a huge write up that i'd like to do. but basically there are two problems with flashing water to steam inside the manifold.

First is that the energy required to take a water from a liquid state into a gaseous one requires almost double the amount of energy it took to heat the water in the first place, (google vaporization energy). I went through some rough calculations on the energy available in 1 gallon of gas, I'll have to find them for a later post. I ended up working out that there would actually be a 4% increase in the volume of gas through the turbine with a very small amount of water per rev.
it would take 9.5 gallons of water per 1 gallon of gasoline burned to recover all of the heat energy in the exhaust AND what would be wasted through the radiator. thats 100% efficiency to get the 4% increase so in the real world it would be less, far less, this was also calculated assuming constant WOT. you would have to preheat the water by eliminating the block radiator and recovering its energy before injecting into the exhaust.

the second problem is that small, even vaorized water droplets will destroy a turbine wheel if it's constantly bombarded. under boost it can reach speed of 10 to 20,000+ rpm's. much like water can cut through steel in a water jet at those speeds the turbine it toast. the inconel is very fragile like ceramic. to get around this one would have to superheat the steam which would require more energy than available.

I was about to build an experimental system but the two facts above caused me to abandon the project. It is possible but not probable without some high tech testing and systems, high temp injectors, check valves to eliminate backbressure in the cylinder and such.

If you try it most likley you will just reduce the overall temp of the exhaust stream causing more lag and within a few miles destroy your turbine wheel.

its a nice though experiment, nice to see that there are others that think like me, 70% of the energy in gas is wasted as heat, keep thinking there potential to be had.

I really enjoy seeing someone put the full thought process to work and proving it. I tried this last Sunday, in 2 different ways, and you are right. Pre-heated, gaseous steam injected into the exhaust via a EGT bung, although denser, cools the exhaust to the point lag becomes noticeably worse. I know, as mentioned by others, droplets will damage the turbine. The second test made me nervous as hell due to the risk of cracking my exhaust header and damaging my turbine, but I did try injecting a small amount of water in a mist into the exhaust stream. Again, loss of power, increased lag. It seems there MUST be additional ways to harness the huge amount of energy wasted in lost heat besides the known techniques... I am still thinking about it, but I would have to agree that the physics have shown the additional heating, plus injecion at lower temp into the exhaust prior to the turbo is not effective........ Unfortunantly. It sounded good in my head when I thought of it, but reality has proved otherwise.

Thank you all for the additional input.

 

[eclipsh]

The one thing I haven't seen brought up in this is the back pressure that this might create on the engine itself. Pressure pushes equally in all directions which could include right back into the combustion chamber and intake manifold etc. Obviously there are valves opening and closing which should prevent a lot of this but it stands to reason that the injected steam would be creating a crap ton of pressure trying to go the wrong way (the pressure differential between the exhaust manifold and combustion chamber might be reversed). That strikes me as being a very bad thing.

I do like some other ideas regarding capturing the post-turbo waste heat to run something else, like a generator. It couldn't be a full replacement for the alternator though because it wouldn't operate until the exhaust was good and hot.

That said, what about a system that used the steam to spin a small "turbo" to precharge air before it gets to the intake of the real deal turbo? It'd require a bypass when it wasn't being used as a booster but I can see something like that spinning up quick to give a little extra push.

Also, glad someone mentioned the 6-stroke engine concept. Cool stuff!

Also, the link on capturing waste heat to generate electricity from car exhaust, wicked cool! Makes me want to go build something to do it!

EDIT: After some more thought, and reading another link, if the steam were injected through a nozzle at the right angle right by the blades that might work.

 

[DSMmonster123]

yea I just threw the backpressure problem in at the last minute just to mention it, didn't have time to type all i wanted. you'd have to have some sort of checkvalve system or time the water injection so that the pressure builds when the valves close. just a few of the many problems with a system such as this.

another big one is that the turbine cannot spin faster than the speed of the exhaust gas and by cooling the gas you lower it's speed, it would then be necessary to decrease the size of the manifold runners to get the flow back up to speed.
^This is why heat is needed to power a turbo for those who think exhaust heat plays little to no role flow+heat.

but then that poses another problem because heat changes the speed of sound. a cold gas will create more friction and turbulance at the same mach number than a hot gas and therfore makes it difficult to hit the same speed.

what would be benificial for spool up would be to build a variable runner manifold just like a cyclone intake but on the exhaust side. faster exhaust flow=faster spool up and coupled with a cyclone would be a killer setup. I'd like to try to make one sometime if I get the opportunity.

 

[eclipsh]

DSMonster, you'd probably be better off using a variable vane/geometry turbo.

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Variable Turbo Chargers Geometry (VTG) | Mechanical Engineering

The other possibility would be as mentioned earlier, adding a small additional section to the turbo where steam was the only thing going through. It'd ad drag any time steam wasn't being pumped through it though.

 

[cola]

just put 4 turbos on the downpipe, thatll recover your lost energy

 

[DSMmonster123]

yes a VGT will be the best option overall if you can make a controller for it that works well. The 2 key points to a fast spoling and good top end setup is variability and resonance. as the resonance constantly changes throughout the rpm range so must the setup to accomodate to achive the highest efficiency.

 

[eclipsh]

yes a VGT will be the best option overall if you can make a controller for it that works well. The 2 key points to a fast spoling and good top end setup is variability and resonance. as the resonance constantly changes throughout the rpm range so must the setup to accomodate to achive the highest efficiency.

I don't think it would be too hard to whip something up with an Arduino reading RPMs and a MAP sensor to control a stepper motor actuator. The tricky part would be optimizing the logic. Well, that and building an exhaust system for the turbo. Mitsubishi Heavy Industries does make VGT's but I haven't looked into them.

 

[ed1380]

I know there's at least 2 people on the forums working on that.

I don't think it would be too hard to whip something up with an Arduino reading RPMs and a MAP sensor to control a stepper motor actuator. The tricky part would be optimizing the logic. Well, that and building an exhaust system for the turbo. Mitsubishi Heavy Industries does make VGT's but I haven't looked into them.

 

[eclipsh]

All of the above or sections of it? If so, which sections?

 

[ed1380]

Both they're working on the control circuit and a manifold for it.

 

[Lofty]

Why not have it boil coffee for you and have it spray back into the cabin through the windshield wiper nozzle hoses?
..................................

 

[H@xtGSX]

Why not have it boil coffee for you and have it spray back into the cabin through the windshield wiper nozzle hoses?
..................................

Now that is a damn good idea! I am actually kind of interested in making an onboard coffee pot powered with the exhaust heat now. That would be great for long trips! ............ The funny thing is this would be rediculously easy to do too. The drawback would definently be the added "mega-nerd" factor involved in driving a car with it equipped.

 

[Lofty]

Man, I sat here reading through all the replies trying to think of something intelligent to say to set me from all the other replies.


Well I did one of those two things right.



Maybe something like this?

Cooking dinner on the snowmobile exhaust pipe - YouTube

I don't understand what these Canucks are saying, but I think I understand.

 

[H@xtGSX]

I have cooked quail in aluminum foil on a truck exhaust manifold, and have also boiled water in a pot on a deisel manifold. It's pretty commonplace to do when way out in the desert or mountains camping. I think that would be funny as hell to have a coffeemaker in the glovebox though.

On subject though, the steam idea is not practical for use on the primary turbo. It takes too much of the energy away by sapping heat from the exhaust which should be pushing the turbo. The added density doesn't appear to add any force. A VGT is looking good to me right now, as is series turbos. I don't know how much pressure a series turbo set up would waste, but it surely would max out the capabilty of the motor. They do it in high power diesels and hit pressures of 50+ psi at very low rpm, in comparison to a single turbo system.

 

[97-TSi-Hx35]

cooler exhaust gases = more dense charge (faster spool)

 

[ramsack]

cooler exhaust gases = more dense charge (faster spool)

If you believe that's true then you should put your turbo at the rear of your car and report back.

 

[red_devil]

Ok back to seriousness

Most of the ideas so far seem too complicated. While the whole idea of using exhaust heat as a recovery system is a good idea, I feel that the steam idea would be to complex and heavy. The best route is for electrical storage so that the alternator can switch off and take load off the engine. Or it will be interesting what Subaru do with their electrically-operated turbo. Maybe this would be a useful idea for quick spool up. I just can't find any more info about it.


All-New Subaru WRX: What to Expect - Motor Trend

 

[ramsack]

You can run without an alternator for a 1/4 mile easily already, just have a battery charger back in the pits. All of this electrical forced induction that's been out for years already drains several batteries so quickly it's not worth the weight. I would think their electrically-operated turbo is going to be something like a variable exhaust side. It would take an insane amount of energy to spin a turbo to those RPMs quickly. It would just be so inefficient to use that crank HP to power a huge alternator to power a motor geared up to spin a compressor quickly.

 

[red_devil]

You can run without an alternator for a 1/4 mile easily already, just have a battery charger back in the pits. All of this electrical forced induction that's been out for years already drains several batteries so quickly it's not worth the weight. I would think their electrically-operated turbo is going to be something like a variable exhaust side. It would take an insane amount of energy to spin a turbo to those RPMs quickly. It would just be so inefficient to use that crank HP to power a huge alternator to power a motor geared up to spin a compressor quickly.

Yes you don't need a alternator for drag racing but were talking about quicker spool up which is predominantly for street driving. We will have to see what they come up with but using waste heat to aid spool or reduce engine load will help smaller engines be more effective on the street. I'm sure it's design is not intended to replace a turbo but just to squeeze every bit out of it.

 

[H@xtGSX]

Thus the reason I am leaning toward a series dual turbo system. 1 small, fast spooler, and a larger unit for mid to high range power... I am not talking about switching between turbos either. One would feed the second, a true compound turbo. It works on diesels, but they can handle the 50+ psi a system like that produces. I think it is doable on a 4g63, and I'm sure someone has tried it, but I think the only way to run something like that would be a pressure relief valve prior to a GM MAF blow thru intake, so you could "wastegate" the intake pressure.

 

[ramsack]

Yeah, it's called a pop-off valve, but why make a turbo work hard just to vent the air? It's more sane to just control boost with a wastegate.