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Why hasn't the steam engine been reborn for modern cars? Answered

With present gas/pollution concerns and green tech merging with cars left and right... Why hasn't the steam engine been reborn? I mean what takes MORE power, Electricity to move a 1000lb car or heat up a heating element to heat water and make steam? With tanks strong enough to hold Hydrogen for cars why cant the same tech be used for a steam engine? All the fuel you would need would be water (solar panels/batteries to power heating) but just water for fuel. Thoughts?

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clayhere (author)2015-07-25

The answer is simply 'efficiency'. Steam engines fall into the broad catagory of heat engines. These are systems that usually burn something, and transform the heat into motion.

Any combustible fuel contains a limited amount of energy. The question resolves to "which engine type transforms more fuel into usable motion?"

Because the fire of a steam engine is not internal to the working parts, the boiler, piping and even the cylinder walls radiate heat, and that is pure loss. No amount of insulation or other fiddling at the edges of the problem will make those losses go away. The best possible result would be 25% efficiency. That means at least 75% of the energy released from fuel in the fire box is wasted.
Conversely, an internal combustion engine can achieve up to 33% efficiency. Now, 13% doesn't sound like that much, but think of it this way; you can throw away that fuel after paying for it, or you can use the energy it contains. Choice is yours.

During the 19th century, and well into the 20th men of great learning and experience with steam realised that small steam power plants were, and remain, relatively inefficient. The efficiency figures quoted above are theoretical only. In practice the losses in steam plant are usually a fair bit higher than that, with something like a Stanley Steamer achieving about 10%.

Higher pressures are not the answer either. Higher pressure comes at higher temperatures. The upper limit is the carbonising temperature of oil. Burn your lubricant, and kiss your engine goodbye.

Believe you me, if steam were a practical alternative, there would have been a demonstration by now. Any number of very clever people have addressed the problems of steam efficiency, and they all have hit up against the second law of thermodynamics eventually.

I wish it were so that steam could be practical and efficient. It has some great properties that make it an excellent power source, but the cost of fuel prohibits it so much that it's cheaper to buy a six speed fully automatic transmission than waste as much fuel as steam does.

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BillP94 (author)clayhere2016-11-23

Yes, ICEs can get up to 33%, but that does not imply all of them are as efficient. Heck, Sterling engines can get be just as efficient.

Steam is a practical alternative. In the 1920s, the Doble steam car could start in less than a minute, accelerate to 60mph in less than 10 seconds, and had a top speed of around 120mph. That was 90 years ago. Today, a steam car would be even better if properly engineered and built.

The question of efficiency is a big one. But there's more than just the efficiency of the engine that you need to take into account. There's also the transmission. With steam engines, you don't need a transmission and drive train. Direct drive is preferable for steam, thus they have less losses throughout the entire car. But what about ICEs? 33% * 85%(this assumes 15% loss, it can be much worse) is less than 10% efficient. This means, that in a normal ICE powered car, you waste *MORE* fuel. The devil is always in the details.

So, steam should have a fighting chance. What gives? Infrastructure. Mechanics in their shops know much more about ICEs and how to fix them than they do about steam engines. But there's also the Model T and cost. Model Ts, in the early 20s, cost very little compared to your average steam car. Why is this? Well, steam cars weren't built to be inexpensive. ICE cars were. Thus, they were more popular.

But, even beyond those, people still have misconceptions about steam that run far too deep. Many believe it to be very inefficient. This is not the case for well built examples.

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BillP94 (author)BillP942016-11-23

I messed up my math there. Woops. 33% * 85% is around 28%. But we're assuming the best case scenario for both the engine and the drivetrain. It would likely be around 25% * 70%, which is around 17.5%. There would be far less losses in a steam powered car. So, 20% times, oh, let's say 95% (it doesn't have a transmission, and may not even have gears on it, so it's possible). This gives us 19% as a possibility.

Basically, it depends on the engine and the transmission/drivetrain.

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BillP94 (author)2016-11-23

Infrastructure. Do you know of any mechanics who can fix a steam powered car? Didn't think so.

Misconceptions. Sadly, many people believe that steam is from a bygone era. Of course, they're very wrong. It's still used in almost every power plant even today. Turbines are always getting better.

From a technical perspective, the only drawbacks are startup time and low power to weight. However, these can be dealt with.

Many will cite the lower efficiency of steam engines. I will counter that with a few things:

It's not much lower. 20% compared to 30% isn't very bad at all.

The ICE has to have drivetrains, with inefficiencies cropping up. You can lose a lot of power from drivetrain losses. Sometimes it's up to 50%! Yikes! With steam you don't even need a transmission, where much of the losses crop up. Meaning that you might actually use less fuel in your steam car, depending on various factors.

You don't have to throw out all the steam, like in a Stanley. Doble steam cars would keep enough water in a 20 something gallon tank for 1500 miles. Talk about high mpg.

You can use many different fuels. Gasoline, kerosene, woodgas, biofuel, etc.

I'd say they're on a pretty level playing field. But back in the 1920s, they weren't building tens to hundreds of thousands of steam cars like they were ICE cars. And that's why they're not common. It's a long tradition to use ICE powered cars, but steam should be given a fair shot, with good engineering and good business practice.

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KennethW4 (author)2016-02-21

I think weight is a big factor, what if you used a small volume steam engin to charge the batteries, a closed loop system that would simply recycle the same water over and over... This could get your electric car off the grid... But so could solar at your house.... The best strategy is to have batteries with long enough run time, If the steam engin has a place it will be at home for power generation, Im thinking solar boiler with energy recapturing steam engine, looped through a coil for pottable hot water, now I need a way to heat without the sun, perhaps there could be a thermal energy storage device and the engine could charge batteries for heat pump and low voltage lighting with LED.....

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LorenJ (author)2015-09-08

Thought I'm not as technically savy as most on here, I do remember a few things having spent years operating large steam turbines. I'll only mention (from memory) some of the things that I didn't see posted here.

1. 'Economy of size', The larger the steam turbine, the more mass; which took more fuel to heat this mass...but this mass comes in handy once it's up to optimal running conditions (rotating at optimal speed) it acted like a giant fly-wheel. It took more energy to get the mass upto speed + equal heating of the mass to reduce metal stress/expansion than it takes to keep that mass at optimal speed and temps.

2. The longer this mass runs at optimal, the more economical it becomes.

3. In turbines, you have to use super-heated steam. a. heat water to saturated steam b. heat saturated steam to super-heated steam. This is critical to avoid water hammer on the turbine blades which will destroy the turbine... in a catastophic way.

4. saturated steam has ( 1600 to 1800 ) times the volume of water. This is why a rupture anywhere in the system is very dangerous. The pressure (horse-power) of the steam has to go somewhere.

5. super-heated steam has an even higher volume than saturated steam. You can't see super-heated steam. When we would have a pin-hole (leak) in a superheated steam line, you wouldn't see steam coming out but you could hear it. It sounded like a ruptured high pressure air leak. We used long wooden sticks with rags tied on the end to find where the pin-hole was. (It was similar to a non-visible laser beam; it would cut you in two)

I'm not sure if any of this was helpful but maybe some of the readers of this article have a better understanding os the power of steam.

Now, I do have a question, thinking outside the box....

1. Can we use a liquid other than water? A liquid with a lower boiling point or is this an impossibility? Would a lower boiling point liquid turn to steam/pressure?

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BearA (author)2015-06-29

Why steam isn't more popular and why it hasn't made a comeback is largely due to misconceptions about steam.

1: "Steam requires huge boilers and engines". Wrong; steam boilers were getting quite small by the late 1800s by using what is known as 'on-demand' steam boilers. and by the 1930s many patents were issued for very small designs that produced tremendous power. In fact, by the 1920s, steam power was very comparable in mass to diesel or gasoline and more reliable...BUT steam required more attention and internal combustion engines were safer than traditional steam. So even advancements in safety were generally ignored in favor of the 'newer and better' technology. I also think that advancements in metallurgy and the advent of micro-controllers was needed for steam to be truly viable. And today we have that.

2: "Steam is a bomb waiting to happen". While yes, steam can be VERY dangerous, due to the high pressure, it doesn't burn. And with modern boiler designs only a very small amount of water is boiled at a time. So that a catastrophic failure would have very little danger. Plus we don't use soft steel or rivets to hold things together anymore either. And these advanced happened way back between 1870s and 1930s. And many advances have come since then due to people continually seeing the value.

3: "Steam is dirty". True! Well, sort of. They used to be. But with modern burning processes there is no reason why steam can't have a cleaner burning process than gasoline or diesel.

So in the end, the biggest reason why we don't use steam is probably because of market resistance to replacing the gasoline or diesel standard and the ease of use we've gotten used to. But truth be told, with modern developments, it is likely a person driving a steam powered vehicle would not even be noticed as they too filled up on diesel, methanol or ethanol.

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As for reasons why we SHOULD be using steam; Using the burn methods used in the biomass heating industry, specifically gasification of bio-friendly materials would allow Steam to run around 90% efficient. And the exhaust produced would be carbon neutral; as long as things like switchgrass pellets or manure pellets are used. Gasifying pellets is easy and easily automated. Maintenance requires notably more attention than liquid-fueled boilers. However, liquid fuel steam boilers running Switchgrass derived bio-diesel can be made to burn extremely clean using very high temperature burners. Remember, one limitation of internal combustion engines is that they cannot allow the burn chamber to get too hot or things will fail.(melt, crack or seize up). However, in an 'external' combustion engine like a steam engine, the power cycle and power producer are separated. The piston has dry steam and is always a two-stroke. So the engines themselves are smaller, lighter and simpler. The boiler can be small simple and compact as well. Using modern technologies we can produce very high pressure combustion environments with non-metallic walls, instead using ceramics to allow much higher temperatures to be maintained. ICE engines must cool the cylinder walls and piston as quickly as possible, so the burning process takes place within a cooler environment which limits the peak temperatures reached. And much of the energy lost is lost through poor combustion and active cooling. ECE engines use that heat to make more power. (a form of passive cooling) ECE engines can be designed to burn their fuels at extremely high temps thereby burning cleaner and far more efficiently.

In the alternative energy field we use gasification to burn solid fuels, such as wood, grass or manure pellets, at extremely high temps. We are limited by the materials we use. Generally speaking, your typical steel will melt around 2,700*F. But we aim to burn at 2,800*F. So you see the dilemma. What we end up doing is using firebrick to protect the steel from the heat. The firebrick can handle higher temps without breaking down. Regular firebrick can withstand 2,900*F. However, high-porcelain firebrick can withstand 3,200*F. Even then we are able to literally burn the brick. We burn regular old wood so hot you could melt titanium. So we need to use a special coating for on the brick that can withstand temps as high as 4,400*F. (We have measured temps of 2,300*F more than 60" from the actual flame.) All of this effort allows us to burn at 94% efficiency. So making highly efficient steam boiler would only be a very small step up from where we are already. Our designs are meant to maintain several hundred gallons of hot water at 180*F to be used for heating buildings, but it would be easy to make steam.

Also remember that all electric generator plants use steam. Regardless of if they are coal, gas or nuclear powered.

As for modern usage I would suggest using steam for things like trains, semi-trucks, heavy equipment, ships, and larger vehicles in general such as full sized pickup trucks, city buses, military tanks and other armored vehicles. Whereas I would not want to use steam for small vehicles like family cars, small trucks or motorcycles.

While steam can be used for almost any role, due to its limitations (mainly increased maintenance), steam would be much better used in industrial applications and for home backup energy production.

For some very interesting steam engine designs check out

http://www.douglas-self.com/MUSEUM/museum.htm

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KennyN1 (author)2015-06-04

Water is purified and reused by the environment in large amounts every day and plants can be replanted every year. Oil is replenished by the environment over centuries. I don't know about you, but I'd rather rely on a multi-thousand dollar plant and water guzzling machine that I know would keep going as long as there's good soil and sunlight than waste the same amount of money on an oil/gasoline/diesel guzzling machine that could go obsolete any time now.

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rowerwet (author)2009-08-02

jay leno has a few steam powered cars, he has written about them in Popular Mechanics. one is the stanley steamer, you had to start the fire about 30 min. before you wanted to go anywhere, and stop and stoke the coals every 25 miles or so. the cool one he has is powered by steam that is heated by gasoline, it is an instant on type, you step on the pedal it goes, just like a modern car. there are quartz rods that swell above a certain temp that shut off the fire until the steam tank cools enough to cause the quartz rods to shrink and allow more fire. The tolerances on the cars system are so tight it doesn't need new water almost ever. It is a closed loop, meaning the steam is condensed back into water and heated again. They only made 13 or so of them as the main designer was so focused on making a perfect car, he couldn't produce many before going bankrupt. That concept today would be awsome as a side effect of the quartz rod system is that you get 100% combustion due to the hight temps. (per what jay says) I would like to see one that was fueled by wood pellets, as coal is not the easiest to get today everywhere. mabey if we realy ever do run out of oil I'll try it. Pellets can be bought almost anywhere, and with the technology used in pellet stoves like my Central Boiler Maxim M-175 pellet boiler that I heat my house with, it would only require an early warm up to get going. Popluar Mechanics did have a short article recently about a new steam engine that has a rather high efficiency and is small. I think it was being or is patented and the designer is looking for applications to use it.

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sarge89or (author)rowerwet2009-08-28

The greenies would lynch you for burning their precious trees. How long does it take to grow wood? If everyone was looking for wood to power their cars, how long would our forests last? Burning wood emits the same green house gases as gasoline, oil, and coal. End result -- keep using gasoline and save our trees.

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KennyN1 (author)sarge89or2015-06-04

To pump and separate gasoline, you need to jump all sorts of legal and technological hurdles then you'd still be SOL when your fossil fuel wells dry up and you'd be long dead before any more fuel can be produced. With Biofuel like trees, corn or soy, you can plant and harvest your own fuel in as little as once every year with little to no trouble. Take care of your soil though.

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VioletGiraffe (author)sarge89or2014-01-08

How long does it take for oil to be produced from fossils?

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GroundingStick (author)sarge89or2009-11-02

Except that mineral oil takes alot longer to replenish, and produces greater pollution.
Ever heard of a tree-spill in coastal waters killing the ocean life?
There are fast-growing trees, and harvesting plans.
With a little responsible foresting we can come a long way!

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afridave (author)GroundingStick2010-10-19

i agree with a bit of sensible managment and less greed and interest in establishing billions of dollars in profit we can make every thing we need out of wood , and it is totally renewable.....through out all of our history on earth we have two great great best friends.......timber and horses and i dont see why we cant use them still.

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steamerandy (author)rowerwet2011-11-23

Wrong. The stanly ran on Kerosine. The early non-condensing Stanley's had to stop of water every 25 miles or so.

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shea.rico (author)2014-08-10

I've been working on a design lately, to create steam inline on it's way to the engine from the water tank. (as opposed to using an absurdly large boiler) To help recapture some of the lost energy, I want to make the vanes in the condenser out of thermovoltaic cells. Coupling this with the use of supercapacitors should extend the life of the batteries.

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dave.hukom (author)2014-07-30

What if the steam engine is run at a rate that can fully charge a battery pack which in turn runs an electric motor. The closed loop system will run at an optimum rate enough to constantly keep the charge of the battery system. Just a thought.

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dave.hukom (author)2014-07-30

Will the electricity generated enough to keep the water boiling on a closed loop as well?

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VioletGiraffe (author)2014-01-08

Is there any working steam road car in the world nowadays? I really doubt Doble steamer is not the most efficient engine possible. This discussion leads me to believe steam engine is less efficient than ICE, but how much less, exactly?
Is it possible to calculate / estimate theoretic peak efficiency of ICE and steam engine for given fuel type?

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Squ33 (author)2009-05-22

The main problem with steam engines, even turbines, is that their efficiency is lower than a electric motor (which is between 85-90%). Also, you are carrying around water which adds weight to vehicle, however, a better external combustion engine setup would be a closed loop gas turbine engine (basically a steam turbine that uses a gas instead of water/steam), that powers and electric generator to power a car.

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skaar (author)Squ332011-01-26

so, the batteries in electric cars... to get the same range as gasoline and steam, are weightless?

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Squ33 (author)skaar2011-01-26

The batteries in electric cars have nowhere near the same chemical potential energy per unit mass that gasoline has. The only fuel source that surpasses regular unleaded gasoline is diesel, though you might still consider this gas. Though I like diesel engines and fuel since you get a higher efficiency heat engine (therefore utilizing more of the energy from the heat of combustion).

I hope I answered your question.

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steamerandy (author)Squ332011-11-23

So where do you think the electricity comes from?

tI comes primarly from steam powered electric generating plants. And most are coal fired. Bad Bad Bad. Over all less efficient even though power plant efficiency is high. Line losses in the electric distrubution system reduce efficience to less then an IC engine. Thare also losses in converting AC to DC to charge the batteries.

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Totally true, BUT we're not running out of uranium anytime soon, unlike fossil fuels. Also, there's this hope in the air that we'll finally get a nuclear fusion power plant working soon. After all, we've been trying for 40 years!

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skaar (author)Squ332011-01-26

actually, was thinking you were leaving something out, and pointing... electrics have lots of weight in the batteries, the weight of an electric power plant is currently, heavier than a gas or steam power plant, by far. when thinking about steam, there's a tradeoff, weight of condensers, or weight in water, but for a full charge/tank, diesel heated steam, or steam in general, beats electricity, due to the batteries needing to be heavy, and taking a lot of time to recharge.

there was a thing, a company was started to test market swappable battery packs, the electricity given free, the charge mostly from solar, auto battery swap stations, and the batteries being the prime sellers(expensive in any case). if that became a big thing, and as easily available as gas or other fuels, it'd make a big dent in the reasons electrics suck, and way more sensible than hydrogen power.

most steam engine development, as far as automotive power, is slowly grinding out, and barely changed since steam fell out of favour, at the turn of last century, and mostly still focused on heavy engines. the main thrust that's slow to catch on, is use of aluminum, it's big with 'toy' steam motors, but that's about it.

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Squ33 (author)skaar2011-01-26

The swappable battery packs station idea still can't compete with the gas engine. Most battery packs give enough energy for 45 miles on average (though the Tesla an go approximately 200 mi, but if you can spend about $60k on a 2 seater sports car, go for it), which would make long trips impractical. An electric 18 wheeler...I couldn't see it happen.

In regard to steam, it takes a lot of energy to heat it to the point where it is saturated steam, let alone superheated steam. Easy calculation:

Cp of water (4.2 kJ/K*kg, avg) + Heat of Vaporization ( ~2.3 kJ/kg). Now 15 gal of water starting at room temperature ( ~70 F) takes:

15 gal ~ 56.78 L ~ 56.78 kg of water
70 F ~ 294 K

So total energy to make low pressure steam:

4.2 (kJ/kg*K) * 79 K *56.78 kg = 18.84 MJ + 2.3 (kJ/kg) * 56.78 kg = 18.97 MJ total

If you use diesel fuel to accomplish this, then you will need to use 1/2 L of diesel (of course this is under the assumption of a thermally isolated system).

I don't want to completely down the idea of a steam transportation system (b/c i do think that it is cool), however it seems quite impractical.

P.S.- Unless you are going to use Aircraft Aluminum alloy ($$$$) for a steam engine, it will probably fail due to the weakness of Al..versus Steel or even ceramic.

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steamerandy (author)Squ332011-11-23

Better check another source on the Tesla. Top Gear for instance. Really only around 40 miles and took 6 hours to recharge.

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skaar (author)Squ332011-01-26

yep, takes a lot of energy, to heat the water to the boiling point, then throw the heat away, which is why some measure of water recycling is used on larger vehicles. steam motorcycles, with pitiful condensing, only go a little way before the water's gone, but still plenty of fuel. any vehicle, of equal weight and drag coefficient, is going to take the exact same amount of energy to move, so the better energy conversion system wins. also, with a better conversion rate, decent condensing, and consequently, very small amount of water needed, it would be much lighter than a non-condensing system.

for the aluminum... yeah, aircraft aluminum would be mighty expensive, which is why nobody uses it in steam engines. there are plenty of people that do use iron cylinder liners from diesel engines, and steel rods/spacers to hold things together. the main bulk of the motor can be made of the cheapest alu alloy available, with the parts that need strength, made of steel. for the anal retentive, carbon fibre could be used, but since steam engines work better hot, unlike IC which works better cold, it'd have to be something outside the actual motor.

with many steam motors, only saturated steam is needed, so, choosing those motors would be part of the design process.

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steamerandy (author)skaar2011-11-23

New batteries have been developed that are actually very light. But the inviormental cost and health risks are really not worth it. Do a search on rare earth minning. Even China is cracking down on minning.

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VioletGiraffe (author)Squ332014-01-08

Hey, and guess how electricity is made? That's right, by a steam turbine! Be it a gas, coal or nuclear power plant - same old steam turbine. No better way has been invented yet. So you have inherent efficiency of a steam turbine fed by burning fuel, let's say 70% (I think in reality it's less), and THEN it's penalized by 85-90% efficiency of an electric car, resulting in 63%...

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Thunderbucket (author)2009-05-14

Check out the Besler steam powered airplane on Youtube you may be pleasantly surprised
http://www.youtube.com/watch?v=UPEv_M7p4fA

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I've always been taught by physics books that steam can't fly. However, it was believed that a human can't fly using his muscle force either, and Sikorskiy's award is finally handed, so who knows.

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sarge89or (author)Thunderbucket2009-08-28

Gee, I wonder why they never flew the plane for more than 5 minutes at a time? I also wonder if it was so efficient and could do what they claimed, why was it never produced beyond the single plane they built? I smell a rat!

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skaar (author)sarge89or2011-01-26

it was experimental at the time, and considering the first powered flight was driven by steam... and the plane crashed, trepidation was probably a good idea.

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NachoMahma (author)2009-04-17

. The biggest impediment is that it takes a while for a 100 HP boiler to start making steam. You can't just turn the key and start driving.
. Steam is much more complicated mechanically and requires more maintenance than electric or ICE. I can't find any power:weight figures, but I'm betting the ratio is lower for steam.
. The only real advantage steam has is that the burners can be designed for lower CO/NOx emissions than most ICEs. But you're still dumping carbon into the air.
. There are probably some truck applications where a steam engine would be advantageous, but not for general automotive use.

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steamerandy (author)NachoMahma2011-11-23

The White steamer could be started from cold in a few minuts. The Doble started from cold in 2 minuts. The Cyclone 100 HP Steam engine can start from cold in seconds.

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Actually, the Wikipedia mentions that Doble advertised cold startup time at 40 seconds. Furthermore, Jay Leno owns a Doble steam car, there's a video about it on Jay Leno's Garage youtube channel. The video was probably edited, but it seems that it only took him maybe 2 minutes to start, so sounds plausible. Here's a link: http://www.youtube.com/watch?v=ACO-HXvrRz8

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steampsycho (author)steamerandy2013-01-31

YES! Cyclone! C'mon people! Steam is viable for modern transportation! Has been since the twenties!

www.cyclonepower.com

www.teamsteamusa.com

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SteamRoss.53 (author)2013-01-03

I have just come across this forum and found it very interesting to read, there are many varied and interesting answers and ideas. I have spent many years maintaining and operating steam engines of all types from steam locomotives, traction engines, excavators (steam shovel), Stanley Steamers, triple expansion condensing marine engines and marine main propulsion turbines and power generation turbines.

Squ33 obviously knows something about thermodynamics and has hit the nail on the head and explained one reason why steam engines are not at the moment really practical in the modern family car. Modern diesel engines are by far the most efficient prime mover these days and are developing all the time. Manufactures of large slow speed two stoke marine main propulsion diesel engines are claiming efficiencies of up to 65% nowadays. I am not sure of the exact figures but it is of that order. Thermodynamically speaking diesel engines are the most efficient power plant available today. Having said that a viable steam car can be built, but there are many drawbacks.

This is a very complex subject and I have discussed it with many knowledgeable people and read and thought about it over many years, to go through all the issues and give accurate facts and figures would take me a long time to get all the relevant information together. I could perhaps write a paper one day.

To answer some of the ideas and questions put here I submit the following:-

The most practical form of steam engine for use in a car is the reciprocating type of the uniflow principle, using high pressure superheated steam. Stanley steamers operated at between 600 to 800 psi and Doble experimented with pressures up to 980 psi at 850 degrees F. I believe Ted Pritchard here in Australia developed an engine using steam at 1000 psi and had plans for one using steam at 2000 psi. The higher the pressure used the smaller and lighter the engine is for a given power, a feature needed in a steam car. Modern power stations with steam turbines use steam at around 3000 psi and so hot that that the metal at the steam outlet of the boiler is glowing.


Steam turbines are not efficient in small sizes and are impractical for use in a car. They are excellent in large sizes for power generation and ship propulsion. They have fallen out of favour in marine propulsion because of the initial cost and because modern diesels are so efficient. The advantage of turbines over diesel is there reliability and low cost of maintenance. If designed right, installed and operated correctly they last for years with little or no maintenance.

The best type of boiler in my opinion for a steam car is the monotube type as discussed here and was used successfully by Doble and much later by Pritchard. The advantage of the monotube boiler is its power to weight ratio, small size and safety for very high pressures. The risk of explosion is reduced to just a sudden loss of steam in the event of a tube failure which can be contained in the boiler casing. Because of the small volume of water in the boiler the risk of a large explosion is greatly reduced to almost insignificant. Because of this feature most government authorities do not require the operator to have a special licence.


One of the big problems for steam cars is getting rid of the latent heat of condensation when trying to condense the steam back to water. In marine practice there is a ready supply of cooling water to perform this function but with a car you have to rely on air cooling which is limited. As pointed out in some of the posts some of that heat can be recovered easily by heating the feed water with the exhaust steam and or the combustion air can be preheated as well. These two things can be achieved in practice but still leave a lot of heat to get rid of. Some of the other ideas for the use of this excess heat are good in principle but I think are impractical because of the added complexity and weight with a machine that is already packed with stuff.

The only need for modern materials in the engine would be if the engine is to operate at high pressures and temperatures then cylinder wear and metal creep becomes a major problem but there would be some way of overcoming this with modern materials. Aluminium can be used for all the lower temperature parts as in the modern auto engines. Carbon fibre and other exotics are best used in the structure of the car to reduce weight.

One major disadvantage of the steam car is the complexity and amount of equipment required and the attendant weight of it all. This all has to accelerated up to operational speed which requires energy input. Even with modern control equipment which solves some of the old technical issues there is still a problem with weight.

An advantage of the steam car is the ability to burn low grade fuel that does not require as much refining as gasoline or the expensive and toxic additives. Using solid fuel such as coal or wood pellets although it is possible is not really practical for many reasons in a car, I won’t go into that now.

Overall and summing up it is hard to beat the modern internal combustion engine because of it compact size, power to weight ratio, efficiency and ease of use. On the other hand steam power is really best in large sizes and difficult to scale down to fit into a car. But I hope the day will come when we will see practical steam cars in general use, I believe it is not impossible.

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steampsycho (author)SteamRoss.532013-01-31

Check out Harry Schoell's Cyclone Steam Engine.

www.cyclonepower.com

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SteamRoss.53 (author)steampsycho2013-02-02

Yes I have checked out Harry Schoell’s Cyclone Steam engine and it looks very to be a very tidy unit and may have some promise. It is hard to know for sure just how good it is because of the commercial sensitivity they cannot reveal all the details but I have studied the info available on their website. I still have to be convinced that the condenser can truly get rid of all the heat to condense the water completely. Although because of the very high initial pressure the amount of fluid used in the system is very small and it may be achievable.
One of the innovations I can see is the use of water as a lubricant and this keeps the pistons and cylinders cool which otherwise would have wear problems because of the high steam temperature. This of course has the problem of taking away some of the advantage of the high steam temperature and pressure because of the cooling effect of the water. The other thing that does bother me is the small size of the combustion chamber and I wonder if there is sufficient space for complete combustion to take place. But I assume the inventor has overcome this.
The engine is very compact and if its performance is as claimed by the inventor it would be a practical alternative for internal combustion engines.
Having said that I think the modern internal combustion engine is still more efficient but this engine would be able to reduce particulate pollution and could burn a fuel that does not need the same amount of refining and the toxic additives of modern fuels.

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steamerandy (author)SteamRoss.532013-07-25

The combustion chamber that Harry is using is the same as the one I posted on my old web site in 1994. I experimented with various fire box material construction. It is a donut shaped tangentially fired. The steam generation tubs are inside the donut. I was firing with no tubes at some very high rates in small test combustion rings. For higher rates then would be the norm. At no time was there incomplete combustion. The harder it is fired the higher the centrifugal force holding the combustion in the ring.

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steampsycho (author)steamerandy2013-07-25

100hp & 1000lb ft of torque going into production. https://www.facebook.com/CyclonePowerTechnologies/posts/594415553923847:0

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steamerandy (author)steampsycho2013-07-25

I have known Harry, the founder of CyclonePower, for quite a few years now. Sense before there was a CyclonePower.

Like I said in my other post. I think the key to building a good competitive steam car is power range. Efficiency is very dependent on expansion ratio. But over expansion to below the external exhaust pressure is an efficiency killer. Sense most steam engine are controlled by throttling the steam, The efficient power range is limited to full power down to the point the expansion pressure equals the external exhaust pressure. Continued expansion produces an exponentially increasing loss, adversely effecting efficiency. In the efficient power range above expansion there is a fairly constant loss. At full throttle you have a loss due to incomplete expansion. As the engine is throttled down the incomplete expansion loss is decreasing while there is an increasing loss due to throttling. These two losses tend to add up to a constant loss over the throttling range above over expansion. So that range has a fairly flat constant efficiency. Lowing the expansion ratio will increase the throttling range but lower the efficiency. Increasing the boiler pressure will allow more throttling range but will increase the loss due to incomplete expansion. So the engine efficiency will be reduced.

The highest efficiency would be operating as close to full expansion as practical. Using compression to eliminate clearance loss. That is, operating over a constant expansion ratio. Power would have to be controlled by cutoff. To have a constant expansion ratio the engine clearance would have to variable as well as having independent exhaust timing to effect compression to inlet pressure.

The implementation of such an engine is not easy.

The reason power range is so vary important.

As force to overcome aerodynamic wind resistance increases with the square of speed above some speed between 15 to 20 MPH the power requirements is increasing with the cube of the speed. With flat efficiency fuel would also be increasing with the cube of the speed. So efficiency is more important to fuel economy as speed increases. Going from 20 MPH to 60 MPH, a 3 to 1 speed range requires a 3*3*3 = 27 to 1 power range. 20 to 80 MPH is a 4 to 1 speed range requiring a 64 to 1 power range.

It is this power range requirement of an automobile that one is going to have to tackle. I do not see anybody with a ready solution or even acknowledging it exists.

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steampsycho (author)steamerandy2013-07-26

OK, well I "sense" that you seem to know a whole lot about steam engines, so I'm going to have to back out of this conversation. I just find it interesting that steam engines were highly capable 100 years ago, but now, according to you, it is a very difficult engineering challenge to overcome. I guess we'll see when people start dropping Cyclones in project cars in the coming months & years. I'm hopeful that they do well.

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steamerandy (author)steampsycho2013-07-27

The most advanced steam car from the past was the Doble. There were around 40 produced. They got around 16 MPG on kerosene. Kerosene has a bit higher heating value then gasoline. A Cyclone engine has been tested at better then 30% efficiency. But they will not give up any info on power range information. When you look at the power range requirement of the modern passenger vehicle a 2 to 1 efficiency, sweet spot, power range is not enough. I do hope Cyclone achieves success. They are the only ones trying and a lot of money has goon into it.

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steampsycho (author)steamerandy2013-07-27

" But they will not give up any info on power range information."

Other than the 100hp & 1000lb ft dyno numbers?

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steamerandy (author)steampsycho2013-07-28

That is not power range. What is the range of power and efficiency over that range. Piston engines get their best efficiency at the top range of power output. He has also posted that it got 30% efficiency. They will not give the full info on their dino runs. I can not say one way or the other with the full picture. So it's wait and see for now. I am sure Harry is doing his best to make it all work.

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Swedemicke (author)2013-05-07

Hi I am new here and think this is a very interesting discussion.
I do have some in puts that can make the steam car more used in the future. I believe everyone can agree that fossil fuels are bad for us and the environment. It is a fairytale without a happy ending. Oil is so full of energy that it’s close to magic, and we cannot get enough. When you fill up your car you have the equivalent of 2 year hard work for a man in your tank. The oil is never going to end but every day it’s getting more expensive to retrieve. Since the demand for oil is increasing (China, India) the production must go up, but when you cannot increase production any more there is going to be a struggle for oil. You might say that’s in the future so why bother. But it has actually already happened. Peek oil accrued 2004, and now we are waiting for the affect. So now to the alternatives. There are not so many. Solar, wind, water and in places with small populations biofuels. Biofuels cannot replace oil. If we store everything that grows for a whole year on the whole earth( on land and in water) that would not last a day if we consume energy like we do today. When oil is getting more expensive other alternatives becomes more interesting. If you can grow your own fuel to your steam car that’s interesting.

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