Years ago, i read about an inventor who converted a large sedan from gas to steam. basically, he removed the gasoline engine and transmission, and put in a 30 horsepower steam engine. he fired the boiler (which he was able to fit in the engine compartment, with kerosene. From waht i remember, the car didn’t have much acceleration, but could reach 60 MPH quite easily…the main problem he had was carrying enough water to keep the boiler fed.
Would this be a solution for some people? Kerosene is pretty cheap-I wonder how many MPG you could get?
And, how much does such a steam engine cost? Could you convert a gosoline negine to run on steam?
IIRC the problem is not acceleration but the lag in throttle responce. Now anyway you slice it 30 HP is going to suck in the 1/4 mile, but a’modern’ steam engine needs time to get up to ‘power’. It may be useful to run a generator for a hybrid design however.
I don’t think it would be possible to convert a gasoline (internal combustion) engine to run on steam (external combustion), since the way power is produced is completely different. You would need to tear out the original engine and put in a new steam engine.
Issues of performance and acceleration aside, I would be concerned about driving around with an open flame and a tank of kerosene under my hood.
The solution to this is a heat exchanger/condenser arrangement to recycle the water. The accelleration throttle lag issue could just as easily be solved by maintaining a minimum pressure on the system and a valve “clutch” of sorts that only sends steam to the turbines or cylinders when the throttle is depressed.
IIRC UnaPersson is the big steam power guru in these parts.
Does your hot water heater give you nightmares?
Kerosene is actually very stable stuff compared to gasoline and far less prone to being easily or accidentally ignited. One would think that a fuel tank of any kind would, much like today, be located separately from the “hot spot”.
We also had this very long thread on steam cars:
Una weighed in there, along with a buncha other people.
Oh, excuse me - you started that other thread, too.
I just spent 20 minutes fiddling with vehicle performance models.
If this thing weighs in at 3600 lbs, which I’m guessing would be typical for a sedan 20 years ago, you’re looking at a top end between 55 and 65 and quarter mile times in the 28 to 30 second range.
The good news is, you’ll be able to beat fully loaded tractor trailer to the end of a quarter mile… barely. But it’ll probably pass you before five miles go by.
Where I live, it’s about 30 cents per gallon less than regular gasoline. And that price doesn’t include road tax, which would be owed if you used it to fuel a licensed motor vehicle traveling on normal roads. So I question the potential savings in fuel costs.
FWIW I’ve heard several comments regarding the Stanley Streamer as having been able to run rings around anything on the road.
Reputedly no one had ever driven it wide open for any length of time. (It may have been the poor roads of the day and time).
It’s big drawback was warmup or startup time for those who wanted to hop in and go!
I think this is the way to go. The steam engine runs at optimal efficiency all the time, driving a generator, which charges a bank of batteries, and drives four independent electric motors, one on each wheel. Braking energy is conserved by using the motors to generate electricity that is returned to the batteries. It would have acceleration comparable to current hybrids, though I’m not sure how the fuel consumption would compare. But on the surface it seems like the best way to utilize steam power in a vehicle.
Workable? Problems?
The basic problem is that steam engines are an example of the Carnot cycle, where efficiency depends on temperature difference (between the hot and the cold part of the cycle). An “open” cycle where steam is lost would be hopelessly inefficient; any pretense of efficiency implies a large heat exchanger with large amounts of air flow through it - a fruitful source of drag and thus inefficiency.
Given that the internal combustion piston engine has a head start of many decades in the race toward efficiency, I’d say the chance of steam power catching up is close to nil, even assuming you could find someone foolish enough to pony up the money (surely running into billions) for the necessary R&D.
Much less radical pathways (e.g. the Sterling cycle, which uses external combustion) have been investigated and then abandoned.
All heat engines, whether they be steam engines, Otto cycle gasoline engines, Diesel cycle engines or whatever, are limited by the implications of the Carnot cycle. There is no real Carnot cycle engine (although a perfect Stirling or Ericsson engine would achieve Carnot efficiency) - such an engine has to run infinitely slowly to keep all processes in thermodynamic equilibrium. It’s a theoretical construct to illustrate what the limiting factors are. The Carnot cycle proves that the maximum efficiency you can get out a heat engine is:
(T[sub]MAX[/sub]-T[sub]MIN[/sub]) /T[sub]MAX[/sub].
This shows that the higher T[sub]MAX[/sub], the higher the maximum possible efficiency.
Internal combustion engines such as gasoline and diesel engines can have high T[sub]MAX[/sub] because their high temperatures are generated momentarily and intermittently. Steam engines don’t have that luxury - the boiler has to be at T[sub]MAX[/sub] continuously. So either you make the boiler and expander out of gas-turbine superalloys to generate really hot steam, or you accept a lower T[sub]MAX[/sub] in steam engines than in IC engines.
On the other hand, steam engines have some efficiency advantages over Otto cycle (gasoline) engines - they have the same T[sub]MAX[/sub] whatever their power output. The vast majority of the time, the gasoline engine in a car is throttled back, which drastically reduces its T[sub]MAX[/sub]. With urban, stop-start driving, a steam car might give a gasoline car a run for its money for best mpg. But diesel should still beat the both of them.
The other advantage of the steam engine is fuel versatility - in theory you can burn gasoline, diesel, kerosene, vegetable oil, waste oil, wood, coal, whatever.
A long and moderately technical article by a steam car advocate can be read here:
http://www.stanleysteamers.com/modern_steam.htm
Not really related, but you can modify a gasoline engine to run on charcoal or even wood, if you don’t mind hooking a big metal drum full of burning fuel onto it.
http://www.woodgas.com/History.htm
If you want details, do a search and check out other threads.
A couple of points however. Firstly, very powerful and light steam engines are possible and 30 hp should not be taken as being in any sense indicative of what a light steam engine is capable. Secondly, throttle lag times and boiler warm up times were overcome in later development and very quick off the line steam cars would be possible, even from a cold start.
A point you don’t address in your informative post is that this formula also shows the importance of a low T[sub]MIN[/sub] to efficiency (provided we accept that there are practical limits to T[sub]MAX[/sub]). My point is that this is a serious issue when efficiency is an important goal and heat must be rejected to air.
If you’ll recall from the earlier steam car thread, I posted info about the Carter steam car, and it got better gas mileage than the smaller AMC Gremlin which was scheduled to go into production the following year that the article on the Carter car was written. (And I contacted the EPA to see if they had any info on the car, since it was developed with a gov’t grant. Unfortuantely, while they were familiar with the car, they were unable to find the report.)
Now, the Carter car used a transmission, which isn’t really necessary in a steamer, and I’d wager as a detriment to the overall performance of the car. If you took a modern rear wheel drive car, yanked the engine, transmission, and drive shaft out, and replaced it with a steam engine which drove the front wheels, you could probably drop 800 lbs of weight out of the car, provided you kept the weight of the replacement engine, boiler, and water tank down to what the weight of the original engine was. That actually wouldn’t be all that difficult, because an aluminum steam engine would be much lighter than the original gas engine found in the car.
The biggest problem you’d have, is if you tried to convert a late model car over to steam. Because of all the computerized controls in the car, it’d be difficult to get the important things like the speedometer, and other such things to work. You’d probably be forced to yank all the gauges out, replace them with analog gauges, and if the car had ABS, you might run into problems with getting the computer control to work (it depends upon if it likes talking to the engine or the diagnostic computer or not), and you’d definately have problems with it engaging correctly, since they’re programmed based on the weight and weight balance of the car at factory specs. So, you’d be better off buying a pre-computerized car, and working with that.
Now, let’s look at the costs of the conversion. To do this, I’ll use a few assumptions, but one’s that aren’t unreasonable, I don’t think. I paid just over $900 for my 1969 Chrysler Newport, which is about a third of what the average price for one in that condition sells for. The engine, transmission, and driveshaft are probably worth about $1K combined, so were I do something like this, you could basically say I got the car for free. Now, a boiler of the type you’d need for the car sells for $2K. I don’t know what an automobile steam engine goes for, but I imagine that it’s probably about the same price. That’s $4K, and we haven’t even figured in the cost of the extra tank to hold the water, and the necessary work that’s going to have to be done to get the thing in the car and running. We’ll say the total cost for that is another $2K (though I wouldn’t be surprised if it wasn’t closer to $4K). So, we’re at $6K for the cost of this job.
The Chrysler gets an average of 16 MPG on the highway, if I drive 15K miles a year (all highway, just to keep the math simple), that’s 937.5 gallons of gas, which at $2.15/gal works out to $2016 (roughly) a year, in fuel costs. Assuming that by converting to steam I can double the current mileage of the car to 32 MPG, and that kerosene costs as much as gas (in my area it’s about $0.50 more a gallon, than gas is), it’s going to take 6 years for the conversion to pay for itself.
That’s not too bad, but it’s something that’s going to take a lot of time to do, and you won’t start seeing any cost savings until it’s all completed. For about $1k, I could give the car a tune up, slap on an aftermarket fuel injection system, and see a 4 MPG improvement. Or, for $2K, I could buy a Chevy/Geo Metro and get the same, if not better mileage than my steam powered Chrysler. Admittedly, a Metro’s nowhere near as cool as my Chrysler, nor as roomy, but most people would prefer to do that, than to convert something over to steam.
You could, in theory, convert the Metro over to steam, but your improvements in fuel economy aren’t going to be as great (since you’ll be tossing out a smaller percentage of the car’s weight when you ditch the engine and transaxle), and you won’t have any trunk space, since you’ll have to use it as your water tank.
Do you have any examples of automotive steam engines in mind (that produce 80+hp and cost < $4k)?
Off the top of my head? No, but I’ll do some digging here in a bit and see if I can’t find something. The HP of a steamer isn’t quite as critical as that of an ICE’s, since steamers don’t have torque curves like ICEs do. You get full torque out of a steamer at almost all RPMs (which means that it can be real easy to tear something up if you floor it when the car’s sitting at a traffic light).
Yes, the torque characteristics of steam engines are quite unique-which is why (for years) the Stanley steamers were the only automobiles capable of climbing the Mt. Washington carriage road. I also believe that the later Stanleys were pretty sophisticated-they had a lever for FWD-Neutral-Reverse, and a foot-operated throttle. As far as maintaining them , it was pretty simple-add water and clean the burners every week-of course you had a chauffer for that.
The later steam cars (White, Doble) were pretty close to gas powered cars of their day-the Doible had a rnage comparable to a gas powered car, and was quite reliable.
Heck-you could even fire a steam car with coal-should we run out of kerosene.
This is why the idea of V8s which disable half their cylinders while cruising is coming back. Let’s hope they have the bugs out this time. The “cars” in the Shell Mileage Marathon that get a few thousand MPG alternate full throttle and coasting.
For sure one of 'em could!
But Tuckerfan, wouldn’t you rather run a Lycoming?