It seems too obvious to be a solution, but why did we give up on steam power? I believe nuclear power plants essentially work by generating steam, could this model be used in a car? Does steam not provide enough force to move the water and its container?
In: Engineering
What are you going to use to power it?
wood, coal, etc
https://en.wikipedia.org/wiki/Steam_car
They are low power and not terribly practical. The wiki is a good read.
It takes a lot of energy to create steam and power something. It’s a lot easier to just burn gasoline and let that heat push some pistons and move things around.
Back in the early days of atomic power there was a craze to put atomic energy in everything and they did play around with the idea of a nuclear-powered car but it’s not reasonable for a lot of reasons.
Basically all engines are heat engines. They convert heat from a fuel into motion somehow. ‘Steam engines’ do this by boiling off steam, and they are *external combustion* engines. This makes them naturally very bulky, but potentially more efficient.
Petrol and diesel engines are *internal* combustion engines. This allows them to produce far more power, but typically at a somewhat lower efficiency. In these, the burning fuel expands instead of steam.
Plenty of good answers here, but I want to point out one factor nobody seems to have mentioned: safety. To power a car by steam you need to have a large amount of steam. This stuff is hot and under pressure, and if due to some accident or failure the system gets a hole in it, the steam is released. The result is often the driver and passengers getting boiled alive, and in the days of steam cars there were some pretty horrific accidents. This is actually a more dire safety issue than a gasoline car catching fire, because a fire needs both a fuel leak and an ignition source, a risk that can be mitigated by keeping the hot bits of the engine away from the fuel tank. A steam leak doesn’t need an ignition source to be dangerous.
Jay Leno has great videos showing his steam cars. They’re neat but pretty impractical compared to a modern gas or electric car.
All of the comments are good, but I think the most obvious answer would be that the water would have to be heated up. This takes time. So you just couldn’t hop in your car and go.
>I believe nuclear power plants essentially work by generating steam
*Every* power plant that involves some form of heat source – be it nuclear, coal or geothermal – uses steam turbines to turn that heat into electric energy.
They could work, there used to be steam powered cars, but they’re nowhere near practical. They’d have to be huge to compete in any real sense with the power of a modern car. They’re dirty as shit. And, they’re super dangerous. It’s almost a guarantee two steam cars hitting each other would blow up.
They can and they did. But heavy, cumbersome engines (of the time) doomed it. Generally the problem is energy density – gasoline engines develop much more energy/kg of fuel. (other than perhaps nuclear – but then there is the safety and shielding and risk of releasing pollution etc) With the current ICE engine, combustion is translated directly to motion rather than going through the step of heating an intermediate fluid.
The reasons you can’t have a car directly powered by a nuclear reactor is because nuclear reactors generate a lot of radioactive byproducts (not because a car would explode like a bomb if it crashed — it wouldn’t). You’d both need to shield the car to keep the driver and anyone around it alive — and shielding is heavy, and so the weight of your car is going to be massive and unwieldy — and any kind of accident that might damage the internals of the reactor, or breach the containment of the radioactive byproducts, could be extremely contaminating. It’s not worth it.
The best way to have a nuclear-powered car is to generate electricity with a nuclear reactor and store it in the battery of an electric car. You lose some efficiency that way, of course, but it works.
The main vehicles that have been used with nuclear reactors are very large boats (if there is a problem, it sinks, which is not ideal but it won’t spread contamination), some trains (again, few people, room for shielding, etc.), and it has been studied for rockets (but never used like this). In all of these cases you’re talking about vehicles that are relatively few in numbers (unlike cars), relatively large, and if they fail they ideally fail away from most people.
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