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

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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clayhere2 years ago

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.

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.

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.

BillP941 year ago

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.

KennethW41 year ago

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.....

KirakouS1 year ago
LorenJ2 years ago

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?

BearA2 years ago

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.


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


KennyN12 years ago

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.

rowerwet8 years ago
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.
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.

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.

How long does it take for oil to be produced from fossils?
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!
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.
Wrong. The stanly ran on Kerosine. The early non-condensing Stanley's had to stop of water every 25 miles or so.
shea.rico3 years ago

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.

dave.hukom3 years ago

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.

dave.hukom3 years ago

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

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?
Squ338 years ago
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.
skaar Squ336 years ago
so, the batteries in electric cars... to get the same range as gasoline and steam, are weightless?
Squ33 skaar6 years ago
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.
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.
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!
skaar Squ336 years ago
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.
Squ33 skaar6 years ago
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.
Better check another source on the Tesla. Top Gear for instance. Really only around 40 miles and took 6 hours to recharge.

skaar Squ336 years ago
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.
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.
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%...
Check out the Besler steam powered airplane on Youtube you may be pleasantly surprised
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.
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!
skaar sarge89or6 years ago
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.
NachoMahma8 years ago
. 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.
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.
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
YES! Cyclone! C'mon people! Steam is viable for modern transportation! Has been since the twenties!


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.
Check out Harry Schoell's Cyclone Steam Engine.

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.
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.
100hp & 1000lb ft of torque going into production. https://www.facebook.com/CyclonePowerTechnologies/posts/594415553923847:0
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.
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.
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.
" But they will not give up any info on power range information."

Other than the 100hp & 1000lb ft dyno numbers?
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.
Swedemicke4 years ago
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.
steamerandy4 years ago
I have been interested in building a steam car for many many years. Over the years I have learned a lot and changed direction several times.

Steam engines are Rankine cycle engines. They are heat engines as are Otto and Diesel cycle engines. These engines convert heat energy to mechanical energy.

Electric motors convert electrical energy to mechanical energy. Electric motors are very efficient. But were does the electric energy come from? Mostly it would come from the less efficient heat engine. And when the energy transfer losses are figured in. The over all efficiency is far less then directly using a heat engine to power an automobile. Some here have talked about solar energy. Have any of you figured the area it would take to power all the automobiles in use to day? Then there is the batteries. The mining of the materials used in those high energy density batteries is ruining environments, unique habitats, endangering many unique species and workers health all over our planet.

The question. Why hasn't the steam engine been reborn for modern cars?

I would have to say the answer is the lack of skill sets and money coming together. Over the years there have been people interested in developing a steam power vehicle. Harry Schoell is the most recent. The Cyclone engine utilizes most of the best steam engine practices. The combustion chamber is basically the same as the one I published on my web site in 1994. There is always complete combustion. I made test firing's on various lining materials firing many times harder then would have been the norm. In no case were any unburnt substances ever observed in the exhaust. Centerfugal force holds the combustion to outside of the fire ring. Tremendous radiant heat is created and transfered to the outer tubes closest to the fire. The high efficiency of the Cyclone engine comes from not only it's high expansion ratio but tedious detail in capturing lost heat in the exhaust steam and conduction to the cylinder walls, puting it back into the feed water.

A lot of previous work has been done developing a more efficient automotive steam engine. The William's brothers developed a more efficient engine in the 40's and 50's. It was a high compression uni-flow with variable clearance. When I first learned of the Williams engine there was a lot of controversy about the compression theory. Engine cycles are defined by their sequence of thermodynamic processes. The text book cycles are what I call static cycles. They use non time dependent thermodynamic processes. For example the Rankine engine cycle starts with the admission process, a constant pressure process. In a real engine the admission is not a constant pressure process. The pressure varies because of flow restrictions due varying port coverage of the valve and pressure changes both external to the cylinder an in the cylinder. It is really a dynamic flow process. It is possible today with computers to do a dynamic cycle. The text book cycle does not include the dynamic process of heat transfer between the steam and cylinder walls. Nor does it include compression of the steam in the cylinder. Modern text books do not include partial or non expanding cycles. They only include the full expansion cycles used by turbines.

Steam engine efficiency is primarily dependent on it's expansion ratio. As are the Otto and Diesel cycles. But there is one big difference. For the expansion ratio to to have it's full efficiency effect the expansion must take place fully above the external exhaust pressure. The expansion ratio is the full cylinder volume at bottom dead canter including clearance volume, divided by the volume at cutoff also including clearance. Old steam engines had quite a bit of clearance volume. Some due to poor design and some part due to necessity. Condensation in the cylinder could blow the heads off an engine as water is pretty much non compressible. Old engines had very little compression and in fact compression was thought to be bad in a steam engine. But on the contrary that low temperature and passably wet steam makes for a significant loss of efficiency. The incoming steam first has to bring the clearance space up to pressure mixing with the residual steam in the clearance space, It takes a significant amount of heat from the fresh inlet steam to bring the residual steam up to temperature. But the mixed steam temperature will not reach full inlet temperature as a part of the steam at cutoff is low heat residual steam. By closing the exhaust early and compressing residual steam to nearly inlet pressure that loss is avoided. The misunderstanding of compression being bad came from the fact that the engine produced less work for it's size. That is simply because compression takes work lowering the shaft work. But that work is more then made up for in the gain in efficiency. The thing about compression is that compression work is returned on expansion. I.E. In a closed cylinder with a piston. You compress the contained gas in cylinder the pressure will raise. It takes a force to push the piston. That piston will return along the same force path returning to it's original position. Idealy the energy of compressing the gas is returned upon it's expansion to it's original state. Of course there are some losses in the real world friction loss for one. But the up side is that compression reduces the clearance loss of a real engine. This is a debatable part of compression theory: Normally expansion is not down to exhaust pressure. So when the exhaust opens there is a pressure drop in the cylander to exhaust pressure. This by theory should be a isenthalpic process, constant heat content. So up on compression to inlet pressure the residual steam will be at a higher temperature then the inlet steam and have a high enthalpy. So the mixture of residual steam and fresh inlet steam at cutoff will be at a higher temperature as well. The result is that the compression cycle has a higher efficiency then the text book cycle which doesn't include compression or clearance. The Williams brothers boosted a higher efficiency then calculated using the text book cycle. It's only been recently that with the aid of computers or advanced calculators that a compression cycle can be calculated. Using a computer program an iterative method is used to calculate a Rankine compression cycle. The first iteration calculates a cycle having 0 residual steam to get an initial residual steam state. Once we have a residual steam state the residual mas can be figured from the clearance volume. The cutoff state can then be found be solving for the inlet mass that when mixed with the residual steam mass will have the inlet pressure. (still a static cycle figuring constant pressure during admission). The cycle is normalized to have 1 unit mass at cutoff (I.E. 1 pound). The programed cycle calculation iterates until the enthalpy at cutoff is unchanging. Some claimed that the residual uncompressed state should be calculated as an isentropic expansion. I modified the program to do both, having a parameter to set the state any ware between the two methods. As a pure isentropic change the compression cycle calculated efficiency equal to the equivalent text book zero clearnce cycle. The compression pressure was also an input parameter. Calculating an example cycle from an old text book the compression cycle having the same clearance With little compression (equivalent to normal exhaust closure) came very close to actual measured efficiency allowing for frictional and thermal losses. This is old history. I did this around 1995. I have been at this for many years. My first steam engine program was a fortran program written in 1967 that piloted the instantaneous crank torque to rotation angle for a given number of cylinders and cutoff point.

To day though I believe that designing a viable steam engine is making it's highest efficiency cover as large an RPM range as possible and fitting it's efficiency ranges to driving speeds. I think it could have a two speed orbital transmission that can be shifted on the fly without use of a clutch or torque converter. Adjusting efficiency ranges means that the engine will have variable cutoff. So efficiency will depend on the cutoff (expansion ratio). The shorter the cutoff the more efficient the engine. A direct coupled engine will need long overlapping cutoff to get started from a stop. You will need vary high expansion to get efficiency that competes with modern IC cars. the Cyclone engine is doing that, having a 28:1 or higher expansion ratio using very high pressure of 3200 PSIA steam that provides a small speed range before over-expanding. The Cyclone uses a method of auto lowering the expansion, increasing clearance at lower RPM. Power to speed is a cubic relation. That is fuel consumption varies with the cube if the speed when efficiency is constant. For example you would use 1/8 the fuel per mile at 30 MPH as at 60 MPH having constant efficiency. So at low speed efficiency does not have to be as high as at high speed for good gas millage. Harry certainly has the ambition and hopefully the continuing means to make the Cyclone a success.

My approach is quite different. Recient developments have shown the clearance loss can be canceled by compression. However that compression does decrease output. However that is not a negative effect. Quite the opposite. That means that output can be varied by varying clearance and cutoff so as to have a constant expansion ratio. Power comes from the admitted steam which is dependent on cutoff duration. So by increasing or decreasing cutoff and adjusting clearance to maintain the same expansion ratio. Efficiency can be fairly constant. The problem is implementing this. With a single stage expansion cutoff and clearance are by necessity very small. No wiggle room. Not enough range to be usable. Going to multiple stages of expansion (known as compounding) solves the problem. The stages would be adjusted for equal output and at very low power need to be independently throttled. A four stage compound engine having an expansion ratio of 2.34 to 1 in each stage would have an over all expansion ratio of 30 to 1. With minimal clearance each stage could have a 42% cutoff. Going down to 1% cutoff would give a 6.48 to 1 speed range. That could be a 25 MPH to 162 MPH speed range. Or 20 MPH to 128 MPH. That expansion ratio could get as high as 40 to 50 MPG at 60 MPH in a small sports vehicle. Independent stage throttling from inter-stage receivers matched with lowering expansion ratio to avoid over expansion would be used at lower speed. Cutoff could be increased for higher power and speed or acceleration torque.

Still the key is sizing the engine to fit the aerodynamics's and weight of the vehicle so that the highest efficiency covers normal highway speed and doesn't drop off to quickly at lower speed.

Sense efficiency is closely a function of expansion ratio with out over-expanding the physical size of the engine must increase to provide the expansion volume. The efficiency gain per volume of increased expansion is decreasing. That means that every additional increase of efficiency requires and greater and greater increase in expansion volume. Basicly efficiency is costing engine space and you are getting less and less power from increasing volume.

Getting an efficient steam engine design the data needed to fit it to a vehicle for best performance and efficiency is a costly endeavor.
skunkbait8 years ago
Steam engines are awesome! I think the issue of HOW to heat the water is the big thing holding them back. Burning wood, gas, deisel as a heat source doesn't seem super clean or efficient. I think a steam engine could be used in a "hybrid" to conserve fuel. A series of solar "pre-heaters" on the roof, bonnet and boot would be a start. After that, the cooling system for the engine could take over. A lot of cars run around 180 degrees anyway, so why not put that heat to use? Lastly, the heat from the exhaust could be used to further heat the water. I imagine on a hot day, a steam-petrol hybrid could get really good mileage. It wouldn't be as efficient in cold temps, but after the vehicle got warm, the steam might help a little.
would it not be feasible to bypass burning biofuel (petroleum, wood, coal, etc) and instead use induction coils to heat the boiler itself?
A steam enginee is an external combustion engine and can burn most any fuel quite cleanly. But the most pritical fuel what can be bought everyware. But a modern burner can be designed to burn most any light liquid fuel cleanly and be able to use what ever you put in the tank. Fuel oil would be the best as it has higher heat content. But hard to find.
I think this is an excellent idea. This sounds like it'll take a lot of room already, but add in an electric backup, with regenerative brakes and everything else, and you've got a.... Tri-brid? Electric has good acceleration (of course this depends on the transmission) and storing electricity is getting more and more efficient. If you haven't already, go to http://www.teslamotors.com. Wow... I'd still like to build an electric/steam hybrid someday. Also, "waste" heat from the steam plant could be used to generate electricity for the electrical system, just like it does in the regenerative brakes.
If I was filthy rich I might be able to afford the tealamotors car. However, I can think of a lot of other things to do with that amount of money. When these so called green cars can compete on a price basis of my present vehicle I might consider one.
Actually the "Slow" burning of fossil fuels is way more efficient than the "Spark Combustion" in engines. As a note: Gasoline engine powered vehicles only became popular when the electric starter motor was invented. Before this time Steam powered cars where more popular along with electric powered (the first cars) cars.
ctyankee6 years ago
Why hasn't the steam engine been reborn for modern cars?

I'll answer that with a question:

Why hasn't the the petrol engine been retired after > 100 years of service? Then we can proceed to create *long* lists of Pros & Cons for both technologies. And finally we can crumple the lists up in a ball toss them out and conclude that there simply isn't enough pain v. pleasure to force the change.

After reading the thread I've concluded that the Brash team, which this is my first introduction to, is *totally clueless*. Furthermore, the Cyclone group, of which I have some familiarity with, has a fatally flawed engine design.

That said, I submit that here is a solution for a steam driven car that would be economical, practical, etc... But would *still* fail to overcome the general apathy.

How do I know? Because I possess the technology! What I lack is the millions of dollars necessary to overcome the resistance from the public to adopt it.

A few green folks here and there are only sufficient to talk about the problem. However I can state with a high degree of certainty that, if pressed, that every person who reads this will have an excuse *NOT* to put their money where there mouth is!
Thanks for keeping this thread going. One thing to consider is the price of the fuel and availability. Coal is the cheapest and most available fuel. The price seems to be around 1.50 us per 100K btu. Standard car gas runs 35.00 per 100K.

So it would appear that coal is 23 times cheaper per btu than gas. That leaves a lot of room for inefficiency. For example if the steam engine is half as efficient as an ICE then the cost savings would be around 11 times, or like paying 35 cents for a gallon of gas.

The back up compressed air instant start makes perfect sense for autos. Of course the best use in the short term would be in the trucking industry. An average over the road truck would save 300 - 400 per day in fuel costs. That equates to over $100,000 per year. No need for fancy start up systems as these vehicles would rarely need to shut off. A closed loop, highly insulated system would work fine.

Of course coal is high in CO2 so that would need to be solved. I think scrubbing out most of the other pollutants would be easy enough.

Keep on chatting kids! I really enjoyed the comments.
I'm a Hungry, Hungry Horizon Eater, I wanna break the current world land speed record on steam (The British (God bless em) attempt was thwarted by using a turbine (and poor moral as they had no final application for all their valiant efforts), had they used pistons the outright wheel driven record should have easily been theirs).

I also wish to smash the outright Australian record currently set @ 500mph by Rosco and the Aussie invader jet powered car and do it with a wheel driven car (direct drive no gearboxes, not needed due to the huge torque available).

I wanna run 600+MPH (666MPH sounds like a good target to aim for) 5000+ horsepower plus huge torque is required to run these speeds (would dearly love to crack the sound barrier with a wheel driven car, but I really think that traction would be an issue to push through Mach 1).

Any input would be nice.

Currently we are looking at using monotube steam generators (note not boilers / the term boiler always gives people flash backs of early dangerous pressure vessels, I much prefer the term steam generator) using hydrogen cracked from water as the fuel.

All types of engine layouts have been considered, however I am leaning heavily towards a Deltic opposed piston layout, due to it's inherent compactness, utilizing modern materials, roller bearings, solenoid valves and possibly refrigerated exhaust ports to help condense the steam and evacuate the expansion cylinder quicker. It should also be possible to introduce a lower pressure area on the exhaust side to aid this. Any thoughts!

Although diesel Deltics fell out of favour in electrical power generation due to huge component counts and high uneven wear, you do have two pistons per cylinder and three crankshafts geared to an output shaft, if you utilized modern materials, coatings etc. to cut wear, they would be very, very suitable for external combustion, ie. steam use, with costs way lower than comparable HP diesels to maintain.

The high wear in deltic's is because at least one of the three banks of cylinders is in the horizontal position causing wear to mainly one side of the pistons, an elegant solution is to rotate the engine at regular service intervals to spread the wear.

Engine design would be modular if you require more power just add more cylinders.

Gearboxes are not required and reverse is achieved simply by changing the rotation of the engine.

After setting the world land speed record I intend to then take the engine / steam generator development into truck use in the mining industry initially.

Australia has just introduced a carbon tax which the mining industry really opposes, steam powered trucks could go a long way to beating the tax!

So I'm hitting up the mining industry as a source of development funding (Australian Government grants could be available, but not likely as it would possibly cause an outrage if the government were to sponsor my LSR attempt regardless of the benefits to the country).

I am looking for input no matter how off the wall your ideas may seem, all ideas will go into a sieve and we'll soon sort the crap from the clay.

As for start up times being a problem, remote starting is the answer, as we all have to spend at least some time walking to our car, doing a visual walk around to make sure the car is safe, putting on seat belts etc. so time shouldn't be such an issue (an efficient monotube steam generator can produce useable pressures in under 90sec and this can surely be improved upon) If quicker times are required a stand by low heat could be maintained and would probably be required in a cold climate anyhow to stop freezing issues.

With modern materials, computer controls, computer aided design and some creative thinking steam is the future for the haulage industry.

I'm not looking to totally reinvent the wheel, just looking to pull together existing technology to solve a problem.

I know I haven't touched on hybrids etc. as we aim to keep it fairly simple to lower costs. After all if it ain't cheaper than diesels we can't get people to convert.

I look forward to others ideas comments on the subject.

Ps. Steam is the power source of the future, the military already embraces it, think nuclear powered submarines and aircraft carriers. We just need to get it into general use, and no I'm not talking nuclear powered trucks.

spvz29 ctyankee6 years ago
ctyankee, do you have an opinion on the Saab 9-cylinder steam/compressed air hybrid?
ctyankee spvz296 years ago
Do I have an opinion on...? Yes. 'nuf said ;^)

Seriously, it was '74 and the world was much bigger then! There were no computers so a steam ECU wasn't even a fantasy.. An awful lot has happened in materials science since then. Water still freezes at 0C (32F) so any steam car is at a significant disadvantage by that one fact.

Might the system had some advantages? Sure, but it was more solution looking for a problem. The fuel spin may have been the dominant motivator, but after that the appeal of the project "ran out of steam." {sorry} =^)

Axial pistons makes for a nice compact engine, but the swash plate is still problematic. I did some investigation into a 5/10 cylinder/piston axial design, and I'll say that it's a beast. But I've decided that the radial 12 is where I'm placing my bets.

I gotta admit that the Cyclone with it's candy-apple red features sure is a cool looking model. But that all I think they have... pretty models, not reliable working machines. I know that perception counts, I simply wish I could tolerate the antics of a modern P.T. Barnum.
Ned Kelly8 years ago
Bloke by the name of Pritchard made a steam engine and fitted it to a Falcon car, could start after 50 seconds from cold, and I think it was 20 litres of fuel { old sump oil } and several litres of water to drive from Melbourne to Adelaide roughly about 500 miles , he ran this for a long period, but the design was bought up by an oil Company and nobody has heard of it since , a lot of this story was printed in a Melbourne news paper and several car magazines of the period
Wrong. Ted Pritchard did not sell his car. He was activly working up until a few years ago. He passed away a few years ago. But Britchard steam can still be found in the internat. I think his son is still carring on the effert.
All very interesting!

On the other hand, we could just use our existing resources to make our old city and town centers more enjoyable and safe so we can walk more. Alternatives or existing oil could then be used for non-transit NEEDS.

I'm not trying to be sarcastic, but isn't this a "walk vs. build a Rube Goldberg Breakfast Machine" scenario?
redhawk446 years ago
Now I am getting somewhat bored with this discussion. Put simply a steam engine is impractical in this modern times and the use of a gasifier using the principal of pyrolysis equally so because of the size and bulk of the equipment needed.
Steam is water in the gaseous phase resulting from high temperatures.
When steam is passed over or through incandescent carbon in the absence of oxygen the steam is cracked.
The result is the production of H2, Ch4 and CO with a small amount of CO2.
The majority of the products of this process are flammable FUEL gases.
H2 is Hydrogen, CH4 is Methane, CO is Carbon Monoxide. CO2 Production is so minimal as to be almost irrelevant but at a sufficiently high temperature CO2 will also crack producing carbon and oxygen.

This is a secondary process in a gasifier arising from the production of a small quantity of steam from the moisture in the wood used as the fuel in the gasifier.

In theory the process can produce sufficient volume of gas quickly enough to produce the energy needed to heat the carbon to a high enough temperature ~ 600 to 800 Degrees C, heat the water to produce the steam and provide the fuel to run a motor vehicle.

As there is no requirement for pyrolysis per se there is no need for the large hopper for the wood fuel, nor is there a need for a high pressure boiler.

Brian Thwaites LL.B
14 February 2011

Green_Primus (author) 8 years ago
I think we all agree that the best engine for modern times, very well may be a integration of all previous designs. A combustible fuel source (say hydrogen) starts it > Steam recaptures heat from "gas" > running through a sterling engine > Generating power to run a Electric motor > Powering wheels/prop (what-have-you) >Propelling vehicle... Obviously improvements abond but makes sense idea wise.
too complicated and therefor too expensive to impliment. not to mention the reduction in efficiency due to losses in the mechanical systems.
I believe mass production is the key here, sure, too complicated and expensive in small amounts, but mass production makes almost anything cheaper =P
skaar _Scratch_6 years ago
also... powering the wheels directly from the sterling motor would work fine in many instances. the hydrogen thing... no, most is still made from steam reformed methane, but the methane has more energy before it's chopped up. and a sterling, can use directly heated cylinders, steam would lose a lot of energy by the time it reached them, put the flame right on them, or just use a steam motor.
running a motor to make electricity... might work as a parallel system, to give acceleration with electrics, might be a good addition. but when the batteries are on a charge, they take more than they give, you lose efficiency, so, have to take longer to charge, or have to slow down. kinda defeats the purpose of using them as boost if you don't have decent capacity, which adds weight n stuff.
_Scratch_ skaar6 years ago
You could add the sterling engine on to gather waste heat from the motor and batteries, that would likely add efficiency, you could use that to run a small motor to power, lets say, the radio and a speaker or 2.
skaar _Scratch_6 years ago
that -is- a possibility, a super well designed boiler would have lots of heat enter, and room temperature exhaust, unlikely in a vehicle, so, a stirling could be added, though still complicated. in the drive train, it would be a problem, but using exhaust heat to run one would get some use from otherwise wasted heat.

an option, is since a monotube boiler mostly uses a throttle on the carb to increase speed, there would be more heat wasted, a stirling would be able to help by recovering some, maybe use it to run the ac.
One reason might be that people don't want to use coal, which was a common fuel for heating the water. and gasoline is much stronger and efficient.
I knew an old man who farmed at the time when steam was going out and IC engines were coming in. Mind you the fuel they used in the steam engines was FREE. They could not wait to ditch steam for reliable gasoline and diesel engine with fuel they had to BUY. Steam is very dangerous and required so much fiddling with and watching over that the pay for the steam power operator was 2 or 3 times what the fuel cost.
yep, the price of a fully automatic boiler control system would sink the richest of farms, now the possibility of automatic controls driven by computer, would make them ultra cheap.
skaar skaar6 years ago
oh yea, coal? how bout wood, trash, woodgas, diesel, alcohol, steam storage instead of generation, propane, or something less dirty to handle? heck, even gasoline with a properly designed burner would work.
jtobako7 years ago
Simplest answer? You need a special license to operate a steam boiler in most areas (early boilers had a problem with overpressuring and exploding).

That and a steam engine can be more complicated (in number of parts and what they do) than a typical gas engine.

Don't forget, it took a major recession to get American auto manufacturers to seriously consider hybrid cars as viable sales.
skaar jtobako6 years ago
i've checked the laws, there's many types of boiler, that don't need to meet any particular design rules, or installation rules... not that you'd want to build one intentionally unsafe, and don't require any inspections. i dug up a pdf, current to 2010, that has pressure vessel and boiler laws for all north america, states and provinces. laws don't change all that fast, so, steam is likely legal in your jurisdiction.

as to the exploding problem, some boilers are designed, that even with catastrophic failure, there's no danger, unless you're face to it when it goes. it's cause of this, that monotube boilers are legal, without special license or rigmarole, almost everywhere.
jtobako skaar6 years ago
Steam generating boilers or hot water boilers? How many square inches of boiling surface (which relates to available horsepower) and what pressures?

A simple jewelry steam cleaner, 1 gallon of water, usually run at 60 psi, needs a boilermaker's license in Minnesota. It also takes 30-40 minutes to work up a full head of steam on a 120 v line.
skaar jtobako6 years ago
http://www.nationalboard.org/SiteDocuments/NB-370.pdf there's different rules all over, but there's enough, that most states/provinces could have legal road steam, even small scale, most, only need an approved design.

from what i've learned, tubing being used as a boiler, is legal without design approval, approved installation or inspections... in most places, primarily cause a boiler under 6" isn't considered, by legal definition, a pressure vessel, or, dangerous, or something. a tubing boiler would be a long tube of under 6" tube, the rest of it, would be considered the furnace, but the pressure vessel section would just be tube. then there's water heater tanks, some fail, bring the water to steam, and proper installation is required, but most of the time, is an ignored item, if one of them goes O.o.

in that document, there's some mention of allowances for really low pressure boilers, but then, it may allow larger, higher pressure boilers in the other exceptions lists. it looks like it's mostly non-permanent installations that are easier to make legal.
redhawk446 years ago
You are all thinking of using steam as the working fluid.

There is another way of using steam. The clues are already here.
Larek8 years ago
Steam is a good way to convert Heat to Motion, and is fairly efficent at it (better that a gas-piston engine) The major problem, is the weight. Steam engines have a horrid power-to-weight ratio. So for non-moving uses (like a power plant) the are very good. In a moving use like a car.. This is very bad, since the engine has to lug its weight and its water weight along with the car.
skaar Larek6 years ago
yes... depending on design though, they can be lighter, just... bulkier.
Truss8 years ago
vtvtvt:  Steam engines are generally more thermally efficient than gasoline counterparts.  Typical power stations with mulit-stage reheat and economizer stages will approach 50% efficiency.  Most steel engines have a thermodynamic limit of 37%. 

The reason why steam hasn't caught on is that steam got a bad rap in the early part of the century.  People do not want to wait 40 minutes for a boiler to make steam.  The electric starter really made the the steam engine look 'hard' in the early part of the century.  And if you ever see Jay Leno start one of his steam cars up, you'll see why it was dangerous as well.

A good book to read about the Steam Car is:


I for one, wish there were more developement on steam cars.  If they early builder would have kept refining and developing their ideas early on, we might be all driving steam cars and pollution we be nil.
etaber Truss8 years ago
Modern steam or vapor engines such as the LEAR are practical in many situations. There are newer designs that also have great application. They can't do and shouldn't be expected to do everything exactly the way that a modern car engine does.
You have to look at the application or the particular problem you are trying to solve. Are you looking at solving a pollution problem? Is it the availability or cost of fuel? Is it noise? Each situation must be examined closely.
The Lear system that existed in the 1970's can be used in many circumstances. The problem it had with efficiency could be improved with modern technologies.
Start-up time in steam engines has been reduced to just a few seconds and can be instantaneous with hybrid electric motors or compressed air technology if you are in that big of a rush.
Creating pressures to do work is relatively easy in these engines - it is creating a difference in pressure between the high and low side that is the problem. Mother nature creates wind by creating difference in pressure. Once you create steam in the engine you must condense it back to water which reduces volume. The faster you can condense the water the greater the difference in pressure and the greater your efficiency. The greater the difference in temperature (assuming sufficient surface area) the greater the difference in pressure. Cooler climates would be advantageous and more efficient. Warmer climates would require larger surface areas for condensation and energy expended for fans.
Anyway - it is the application that is important.
Can practical steam cars be put on the highways of America within five years? Absolutely. Can you learn to be happy with the difference between it and your vehicle you now have?  I think so. Will you complain along the way?  No doubt. Did folks complain back at the turn of the twentieth century when we changed from steam cars to internal combustion cars that we have today? They sure did.
Freezing can be solved by high pressure compressed air, burners, plug-in electrical heaters etc.
skaar etaber6 years ago
or boilers that drain when they cool, and water tanks that have truncated pyramidal section, frozen water would just climb the tank walls as it expands.
Jaycub8 years ago
I think wood gasifiers ( http://en.wikipedia.org/wiki/Wood_gas ) are better than steam engines. You can run your car on wood but you don't have to worry about big steam/smoke clouds and the water.
Gasifiers are big and ugly but they work unfoirtunately they are a bit too ungainley for a domestic car, OK for a pickup or if you want to drag a trailer around with you,

I suppose, but it wouldn't be any worse than a big boiler full of water for a steam engine. Gasoline is way more convenient but it is also way more expensive and the supply is not a sure as wood scraps / grass clippings / garbage / whatever else you might put in a gasifier.
skaar Jaycub6 years ago
yes, big boiler... except, there's a design for one, that provides fast steam, enough for a regular entry level car to be driven at highway speeds continuously, and is about the size of a toaster oven(part of it is a catalyst).

gasifiers have their place, for sure, but, i think what the poster may have in mind, is steam storage, with the boiler being part of a home heating system, cause really, making steam electrically, onboard, would be dumb. a tank, filled at home, then later at work, could do better than electrics on a fill, and be easy to fill almost instantly.

with the tank, there's a big benefit, of not having to carry fuel to make steam, it's already made, a water fill and electric element for heating while at rest would work too. it's a much simpler device, only a set of tubes to circulate steam while filling(faster), and a valve to release steam to the throttle.
This is so true. All the advantages of wood fired steam without the dangers or the extra boiler operator to pay.
redhawk446 years ago
H2, CH4 and CO are the products of which simple process?

All are flammable gases. All can, have and do run engines.

PKTraceur8 years ago
Based on the commetn below, the speed is a variable, yet set. You cant exactly control a steam engine. -PKT
what exactly do you think a governor does?
ne2i7 years ago
Was in maine for a steam powered car show. Was cool to see all the old cars. They almost run silently. you had to watch for em.
retrotull7 years ago
Maybe the steam engine has been reborn...check out www.brashengines.com to see a new air steam hybrid development in cooperation with University of Connecticut Mechanical Engineering and funded in part by a DOT Small Business Contract.
glsooter7 years ago
Obviously nobody here has heard of the Cyclone engine http://www.cyclonepower.com/ this is a steam engine that can be scalable from small to extremely large, used to power generators and used to power vehicles. They are in the process of having their 100hp engine going through trials now. In fact they have teamed up with US Land Speed Record team to set a new land speed record for steam powered cars." Cyclone Power Technologies, the owner of this technology, is developing a 6 cylinder, 336lbs, 95HP engine capable of producing up to 860 ft.lbs. of torque at starting, sufficient for powering a full sized passenger automobile. The specially designed USLSR Engine is a non-condensing variation of the Mark V automotive engine offering 180 HP by utilizing a double combustion chamber system.

The patented Cyclone Engine has won numerous awards including the Popular Science 2008 Invention of the Year, and the Society of Automotive Engineers' AEI Tech Award in 2006 and 2008"
Phillps of the netherlands supplied a fleet of busses on th' streets of Amsterdam for about 15 yrs powered by Stirling cycle engines they were experimenting with .  100lb engine producing 150 hp at 3000 rpm and achieving 50 mpg !
Capt. Howdy8 years ago
The way people drive in my area there would have to be a burn unit at every traffic light to treat scalds.
vtvtvt8 years ago
Steam engines are far less efficient than modern gasoline or diesel engines. If you burn a fossil fuel or electricity from a battery to make steam to power a steam engine, it would take much less of the fossil fuel in a modern gas or diesel engine to produce the same amount of power. Batteries directly to electric motors would take far less battery power than trying to make steam. Old fashioned locomotives were often less than 5% efficient. 95% of the heat energy would be wasted blowing out the stack and elsewhere. Modern steam engines in an auto maybe could get around 20% efficient where modern gasoline cars are getting near 40% efficiency, diesels near 50% and electric battery/motor systems around 80%. The only advantage to steam would be that any fuel that can burn would work. Pretty much any fuel that could be burned cleanly to produce steam in an auto could be used much more efficiently in a gas or diesel engine. If the fuel could not be burned in a gas or diesel engine, likely pollution would be a mojor problem or the fuel density would make hauling enough fuel very cumbersome.
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