RX8_GT

Check out the latest Popular Science magazine - unfortunately not on website yet.

System uses waste heat from exhaust and cooling system in two separate systems to generate steam in closed loop to run turbines to hybrid with standard piston engine.

Seems to me that such a system - with a weight of less than 250 lbs - would work in a rotary based system.

Posted this in a couple of hydrogen-based discussions - but no reaction.

guy321

Oh sweet, reminds me of the good old days back in 1896

saturn

All I can think about when I read about this steam technology is a drag race where all the other cars are cruising with their high-pitched whines and turbo whirring and then having this car coming up from behind out of nowhere with a distinct "chugga-chugga-chugga-CHOOOO-CHOOO" sound with all this smoke billowing out of the top of the smoke stack situated right smack dab in the middle of the hood. That would be sweet.

RX8_GT

Sorry Guys:

Closed systems - no steam whistles or venting.

System - like gasoline-electric hybrids - recovers waste energy from the gasoline engine. A lot simpler way to make our fossil fuels last longer than hydrogen, etc.

The development time would be 'short' like the gasoline-electric hybrids of today.

Any engineers out these to comment - hopefully after checking out the article.

rotary crazy

I allways wonder why people dint use a system like this, and the rotary has a clear avantage with its exhaust system

RX8_GT

Rotary Engine is known to be major waster of heat . The cooling system and exhaust system vent a lot of heat. Part of the reason for the poor MPG of the car.

Most of the components of such a system would mount both in front of the engine - where there is lots of room and in the rear part of the exhaust sytem - thus the 50 / 50 weight ratio would be maintained. The system weighs less than 225 lbs - per the article - a very resonable extra load. No major HAZMAT issues - unlike the gasoline-hybrid engines - come to mind.

rx8wannahave

I love Pop-Mech and Pop-Sci....hopefully I'll be able to check it out, sounds interesting.

s13lover

So what would the advantage be of using heat to create steam power instead of electric power?

oh, and how many mpg would that tank of water get?

Im_DANomite

iTrader: (1)

repost https://www.rx8club.com/showthread.p...ight=bmw+steam

RX8_GT

Re-post yes - but newly published in Popular Science.

Still seems very do-able - especially with all the waste heat of the rotary. Weight quoted in popular science is less than 225 lbs. I think that's less than in a gasoline-electric hybrid.

In fact no reason why a gasoline-steam-electric hybrid is not possible. Maximing the IC engine is a short term but quick to reduce fossil fuel use.

John

saturn

CHOOOOOOOOOOOOOOOOOOOOOO-CHOOOOOOOOOOOOOOOOOOOOOOO!

Im_DANomite

iTrader: (1)

but this technology was made for the sake of technology. it doesn't really help out emissions. it boosts power output, ok. but it adds 225 lbs of weight, why not just add force induction if you want power? it's neat, but doesn't really serve any purpose.

daisuke

forced induction (turbocharging) is free power, however even after exiting the turbocharger the exhaust gases are still very hot.

the whole point of this system is to recover all of the waste heat in the exhaust thus achieving as high a thermal efficiency as possible. It reduces emmisions by getting more useful energy out of the fuel and thus you use less fuel and reduce emissions.

I believe the system actually does envision a turbocharger on the engine as well. if you couple them all together and replace the steel in a car with large amounts of aluminum and magnesium you get a car that weighs the same as the one without the steam system but is more efficient.

Im_DANomite

iTrader: (1)

true.

but most of our emissions problems are at the beginning of start up. air pumps, egr, heat o2 sensors, etc. etc. for the steam system to even operate the car has to reach optimal heat. so it still doesn't really solve the emissions point 100%. but yes, i do agree with everything you have said. hence all the questions on the other thread. it's a very neat concept, but i wouldn't want it in my car.

Rumboo

Nah, FI isn't free.. it requires more fuel.

But I do like the idea, cos once the system is up to running temp (pretty quickly, IMO, cos volume of water used in the closed system is small, not much latent heat required), it would start increasing efficiency. I don't expect more power, actually, it's more for fuel economy and saving the earth and all that. I figure if BMW can get it to be feasible (ie save more fuel than it uses to haul its own weight around) in a piston engine, it would be even more feasible in a heat-wasting rotary.

Not sure about this, but i think there isn't a efficient way to convert heat energy directly to electricity yet.. mostly heat->motion->electricity, from what i know.

Rasputin

I agree too, FI is certainly not free. IOverall efficiency always goes down due to ignition retarded from MBT and/or reduction in compression ratio.

Re the steam stuff by BMW, it looks like the Quandt familly does not want to pay Toyota for an electric Hybrid license... So they try other routes.

However, it looks like a good idea t recover some wasted energy, and also to cool down catalyst bricks, instead of throwing buckets of fuel in the exhaust.

BaronVonBigmeat

All electric power except solar and wind turbines are generated by steam turbines. The steam in turn is produced by coal or natural gas or the heat of nuclear reactions. In this case, the heat source is waste heat that would otherwise be discarded out the tailpipe, so there's no fuel cost. Just the added weight, bulk, and expense.

Speaking of which, that's why we don't have steam cars anymore. They are too bulky and heavy, and apparently the throttle response is poor. I seem to remember reading about a stirling engine Ford developed in the 70's...after much development, they had one that was capable of moving a car after "only" 5 minutes of warmup. I guess if gas gets catastrophically expensive, something like that would make sense. It's also a retardedly simple external combustion engine, so you can burn basically anything. Maybe someone could stick one of these in a hybrid car:

http://www.whispergen.com/

RX8_GT

Steam engines in a closed system might be slow to produce power - but if powered by waste heat would 'cost' nothing. Powered by waste heat - they would produce no added emissions.

In the BMW hybrid engine - the steam engine would be additive to gasoline engine which of course can go when started. The reason for two circuits - one low temperature and one high temperature - is to recover heat from both the cooling system and exhaust - both of which are rapidly heated in a rotary engine. Power would be produced quickly - perhaps never enough to move a car on its own - but enough to add into the gasoline engine - thus more torque - something a rotary itself could use.