This has been done for internal combustion engines - first in the late 1930s, I believe. See the photo (lower right) in this link for a modern version.
This topic comes up semi-regularly. Steam cars tend to get bad press for some reason. There tends to be an overemphasis of the problems with early steam cars (warm up time, having large and potentially dangerous boilers, water consumption)
The highlights of the Doble car just make me weep when you consider that if we could build something that good in the early 1900’s you can only imagine what a steam car could be doing by now. 1500 miles before it needed to re-water. 90 mph on a silent engine. 70mph at 900 rpm. 30 seconds to go from a cold start. No large boiler, just a flash boiler (so little energy for an explosion). No clutch, no transmission, no high tension ignition system (all sources of breakdown and wear in an ICE car). Competitive fuel economy with cars of its day.
And Cardinal: why precisely couldn’t a steam car use gas as fuel fer crissakes? Stripped of match by tournament umpire.
Thank you so much for that link. I think that far too much has been written in this thread about problems like explosions or converting the steam back into water, and almost nothing about how to change the water into steam in the first place.
When I think of a steam engine, especially one from circa 1900, I see a locomotive with a man (or two) throwing logs into the furnace. Granted that a car is lighter than a train, and would need correspondingly less energy, but still, how far can you drive with just 3 or 4 logs in the furnace? Instead of gas stations, would we have had log sellers to refill from?
Keeve to run a steam engine you need to burn something to make water boil. That’s it. Can you think of anything that can be burnt to make water boil besides wood? Sheesh.
The problem (I see now) may be that the OP title creates - no doubt unintentionally - a false dichotomy between steam cars and gasoline powered cars. Steam-powered is really a misnomer. Steam engines are just a type of engine. A steam engine could be gas-powered. I suspect the OP really meant to refer to steam engines and internal combustion engines.
Quite right - it can in principle use any heat source.
But if it’s gasoline (or diesel fuel), you’re tempted to ask yourself which is simpler:
- Burn fuel to boil water, making steam; send steam to cylinder where it expands, driving piston; send expanded steam to condenser, where it again becomes water; pump water back to boiler, or
- Inject fuel into cylinder where it burns, driving piston
2/ would more accurately read “inject fuel into piston using highly complex and fiddly system in order to ensure efficient and powerful burn in highly variable conditions while not breaching emission standards, driving piston. Eject exhaust. Drive wheels through complex, heavy and inefficient drivetrain due to inability of engine to generate torque at stall and narrow power band”
Every energy conversion involves a loss of energy. Work requires energy to do the work, and every step inbetween the combustion and the wheel turning is a waste.
The conversion to steam is most profitable only when the energy source can’t provide the volume expansion to drive the cylinder or turbine alone, like in a nuclear electrical plant.
I can do ya one better! 
Here’s a wood gas powered Yugo! :eek:
There are efficiency advantages and disadvantages with both ICE’s and ECE’s. You point to losses at conversion to steam, I point to losses in the power train of an ICE. We could go on all day. I don’t know precisely how the most efficient possible gas powered ICE car would stack up against the most efficient gas powered ECE and suspect you don’t either, but one thing is for sure and that is that it is not the no brainer your answer above suggests.
Gas jumped from $2.09 to $2.19 overnight here in Middle Tennessee.
That was exactly my point, though I guess I was too sleepy to explain it as well as Xema and Cardinal did. Or, I can make another attempt at answering the OP myself:
Steam-powered cars lost out to gasoline-powered because they are stupid and inefficient. If you use wood to boil the water, you’re going to need an awful lot of it. And if you use gasoline to boil the water to turn the engine, why not just have the gasoline do it directly?
I’m still waiting for my nuclear car.
Fascinating!
For those too lazy and/or unable to read that link, here’s some interesting notes about that Yugo:
[ul]Highest speed: 85 km/h[/ul]
[ul]Time needed to start the car: 15-20 minutes[/ul]
[ul]Fuel equivalency: 2.5 kg of wood takes you as far as one liter of gasoline.[/ul]
[ul]MPG and fuel capacity: At one point, he says a “full tank” goes 150 km on 35 kg of wood or coal. At another, he says 100 km per 20 kg. Not identical, but close.[/ul]
[ul]Operating cost: Driving “on wood” can be 1/10 the cost of driving using gasoline.[/ul]
My comments: I can’t comment on cost, since I have no idea how much firewood costs per kg. But people with a long commute to work will have to fill up every day, or even several times in a single day. Forget about long-distance driving.
But even if everyone drove only short distances, think about the distribution network needed to get this much firewood to the masses. My gas tank holds about 10-12 gallons (about 38-45 liters), and it takes me about 250-300 miles (400-480 km). I’d need about 100 kg of wood to go that far.
My point is that 100 kg of wood would take up a lot more space at the fuel station than 40 liters currently does. This will require the fuel distributors to make deliveries far more often than currently. I do realize that there are ancillary benefits, such as wood being far less dangerous than gasoline, and far less polluting, but I really don’t think that the market will allow such inefficiencies. Maybe they can improve on the wood-burners, but until then, faggetaboutit.
To be fair, many of these complications would necessarily be present in a steam car. You’d certainly need a sophisticated combustion control system, which would have to concern itself both with fuel efficiency and emissions. You’d also need a drivetrain, to transmit power from the engine to the wheels.
You’d omit the starter, clutch and gearbox - a definite plus (though these do not consume any staggering amount of power). In return, you’d need a boiler, a condenser (with condensate pump), and the piping that connects them. The condenser is a serious bugbear - for efficiency, it would have to be large, which implies heavy and expensive. You’d have the non-trivial problem of sampling and conditioning the condensate (for long life, boilers like it to be just so). Piston lubrication in a closed system is no bed of roses either.
I don’t know of any examples of steam engines that are both small (i.e. of a size suitable for a modern automobile) and efficient. (I’d very much like to hear of such, if anyone has links.) Stationary steam plants certainly can be efficient, but they are nearly always large and need not concern themselves with being lightweight.
Your insenced attitude points to something else going on here. I don’t know what’s going on in your life, but I have enough stuff of my own without having to take some of yours too.
You have all kinds of reasons given here that steam cars are inefficient: Another energy conversion step, dangerous boilers, the size of the thing, the bad performance, the time delays, the energy escaping as heat. Lump them all together and let’s call it a day.
I thought Princhester was being quite reasonable. He acknowledged both sides of the issue, and suggested that you both wouldn’t be able to resolve it within this thread. I don’t think disagreement about internal or external combustion is exactly cause to ask about underlying personal problems. Princhester’s writing style can be snippy on occasion, but hardly incensed on this one. He had some valid points.
And I’m done with snippy. The snippy-to-complete ass continuum often ruins this board for me, which is really disappointing, as I overall really like this board, and as you might imagine from my join date, I even feel a tiny bit of ownership in it. This increases the feeling that someone is pissing in your garden.
Not to nearly the same extent. A basic problem with an ICE is that the combustion has to take place in extremely awkward circumstances. The fuel has to be ignited, burnt, and then the exhaust extracted in a cyclic fashion. One false move and the ignition occurs to early or too late resulting in pre-detonation or incomplete combustion. Not only that, but the whole thing has to be able to cope with variation on several fronts: when the throttle is opened the whole shebang changes, and that causes the timing of the operation to change as revs increase and that changes everything again. The whole thing is an engineering nightmare and it’s a tribute to engineering skill that the ICE is now fairly efficient.
Running a steady flame for a flash boiler is a piece of cake by comparison.
[I don’t direct the following at you particularly Xema, since you at least seem willing and able to debate the merits].
Time and again I see threads on this topic, and they are just weird, man. You can post links about the Doble car, pointing out it was extremely fast, near silent, as efficient of any ICE car of its day, that it had no time delay, that it had no big or potentially explosive boiler, that its drive train was lighter, easier to use and more reliable than an ICE car, that it had a more even weight distribution than an ICE car (boiler one end, engine at other) that it was no bigger than an ordinary car and yet and yet, at the end of all that, someone will still say [emphasis added]:
and
I give up. Those with open minds can make of the information provided what they will. For others, you believe what you want and ignore what you want, it makes no difference to me.
Please accept my apologies. I do not want to be viewed as closed-minded. I did try to look at the links others posted, and all I saw was two different links which had beautiful photos of cars which had to carry their furnace in a trailer behind the car. But now that you mentioned the Doble Steam Car, I’ve done a bit more research, and I am pretty impressed. I’m going to go read more about it now, and anyone else who wants to read its article on Wikipedia is invited to click and learn.