Exchange loads at truck stops, maybe. I’m not going to try to build a model, but conjecturing that eliminating the driver via automation might make this economically feasible. Or maybe not.
I read an article awhile back that they could construct a road with some sort of electrified cable embedded in the roadbed that could continuously charge the vehicle’s batteries as they drove. Similar idea to those wireless cell phone chargers, but on a much more massive scale. I have to imagine that such a project would be wildly expensive and full of bugs at this stage.
I’m sure a large number of cars that are electric only could be useful to many people. But it still makes sense to have the auxiliary engine in those. If you live in the part of the world above the arctic circle like New England you need heat. I can commute to Boston with a 100 mile round trip, but that could take hours in very cold weather. Lot’s of savings of energy because of the stop and go traffic, but staying warm would be another matter. I could live without AC in some pretty hot areas, but a lot of people wouldn’t be happy about it. All electric with no auxiliary power seems to be a limited case for practical purposes, adding an auxiliary engine would make any car more practical.
I haven’t worked anything out on this, but when you account for the larger electric motors and batteries needed to run a car at highway speeds on electric only and compare that to a car which combines an IC engine with electric I think you’d get the most overall efficiency and practical usage over the wider range of actual driving conditions. All electric sounds like a small niche to me.
The idea that internal combustion engines are more efficient because they waste a lot of heat is inherently contradictory. The engine in your car has a thermal efficiency of probably 20 percent or so: for all that energy being consumed by the engine, an awful lot of it goes to waste, whether it is winter, summer, spring or fall.
An electric motor is several times more efficient than an internal combustion engine, meaning more energy is used for the stuff that you care about (acceleration, lights, radio, heat, AC, etc). The tradeoff is that an electric car can only carry so much energy with it, since batteries are what they are, and a tank of gas contains a hell of a lot of energy.
So it comes down to this: would you rather have: (1) a very efficient motor with smaller energy supply; (2) a very inefficient motor with a large energy supply; or (3) a very efficient motor AND a very inefficient motor WITH BOTH a tiny energy supply (a small battery) and a fairly large energy supply?
What you’re suggesting is (3), which has a niche appeal right now as battery technology needs to continue to develop. But over the medium to long term, the appeal of (1) is going to be much greater, the need for (2) will decline, and (3) will probably continue being niche products. IMHO.
ETA: And one other thing: electric cars drive better. Period.
Almost all Smart cars on the road are gasoline powered. It has a 10-gallon tank and gets 35 mpg. The electric version looks almost identical.
Adding a backup combustion engine for extra range or heat eliminates one of the advantages of an all-electric vehicle: maintenance. I never need oil changes; my maintenance needs are pretty much just filling up the tires occasionally. The complexity of an electric motor is trivial compared to a combustion engine - there’s much less to go wrong, and it’s generally easier to fix if something does.
If you do live in a very cold or very hot climate, you do need more margin in range. Still, there are lots of cars everywhere in the US that are only used for short commutes. I don’t think my car has ever been used more than 100 miles in a day. (We use my wife’s truck for longer trips.)
The way typical American drivers drive, accelerating the car takes a lot more power than maintaining highway speeds. And accelerating is what electric motors do best (very high torque). So gas-electric hybrid cars already have motors powerful enough to maintain highway speeds.
For what it’s worth, in my particular vehicle, the lights, radio, fans, and other accessories are driven off an ordinary car battery completely separate from the huge battery packs for driving. I have no idea if that’s typical, or just because my vehicle is a variant model of one that has non-PHEV (and even non-hybrid) varieties, and it was easier just to not change those components between models.
It’s an interesting thought that fuel-based heat might be more efficient in an EV - alcohol, stabilized methanol, etc. (With electric heat as an emergency backup.)
Yes, this is true. Electric motors need to be larger to accelerate to and maintain highway speeds, but no less efficient at larger sizes. And to be able to run on electric only at highway speeds for short distances makes a lot of sense. So I would say that an auxiliary IC engine could be smaller than necessary for top speed and acceleration, but still extends the range of the vehicle, and in combination with providing heat and charging probably does better than just using batteries to heat a car. If you have both there may be some trade-off point in weight with the electric motor, but it’s going to lean heavily in favor of the electric motor anyway.
As far as maintenance is concerned, modern IC engines do pretty well. They’ll need regular oil changes, plugs and wires and air filters, but they shouldn’t run as much as an IC only car and costs shouldn’t be high. Batteries are a big maintenance issue in any electric, all electric or hybrid, they don’t last forever. The rest of the car will need just as much maintenance either way, brakes, drive train, tires, those are still factors. So a hybrid has somewhat higher maintenance than all electric, but is more versatile.
Going back to one of my original points, the cars that are routinely driven longer distances use more of the total fossil fuel than those that are only driven short distances. Those cars being hybrids will have the greatest effect on reducing fossil fuel use, and those same cars will be just as effective as the electric only when driven shorter range.
Typical combined fuel efficiency for an ICE car is 22-25mpg
Hybrids can get up in the 50 mpg range
Electrics are in the 90-100 mpg range.
So about 4x. Most people don’t have a good grasp of exactly how inefficient their cars are. Very.