Direct mechanical drive is far more efficient than conversion. That’s not “cheating”, that’s common sense.
The ONLY reason they have diesel electric locomotives is the necessity to power all the small wheels because of the low coefficient of steel wheels on steel rails.
The main reason locomotives use the diesel/generator/motor combination is that such an arrangment provides an infinite speed transmission.
The engineer can transmit an infinite range of horsepower to the drive axles, from a couple horsepower to the 4400 rated horsepower and beyond.
The locomotive can also respond nearly instantly to slippage on any single axle, reducing power to that axle. Dynamic braking, something difficult for a mechanical connection, is also available.
It has nothing to do with the number of drive wheels.
It’s more than common sense. It’s the Second Law of Thermodynamics.
The Three Laws of Thermo go like this:
1. You can’t win. (ie, you can’t create more energy than you started with)
2. Not only can you not win, you can’t even break even. (any time you convert energy from one form to another, there’s a conversion loss)
3. You can’t quit the game. (you can’t create some isolated, special environment in which the first two laws don’t hold, because the outside universe will enforce the first two laws from outside your little unicorn habitat.)
As for diesel-electrics: That’s part of the reason. The other is that when diesel/electrics first started, they used series-wound DC motors. For those who don’t read up on various types of motors for fun and profit, series-wound DC motors produce incredibly high torque into a stalled load - just what you want when you need to get a train off the stopped position. If you were to try to drive the wheels directly from the diesel, you’d have to have some manner of clutch to bring the load onto the engine without stalling it.
This is unlike steam, where you can directly couple the expansion pistons to the wheels without a clutch. You can’t do with diesel engines.
Today, diesel-electrics use different types of motors with modern, solid-state DC motor drives, which allow the engineer to control the torque and acceleration to a very fine degree, which enables longer trains.
1) The car is sold as an electric car.
2) The engine is there to charge the batteries and drive the drive motor and an engine’s efficiencies if it is tuned for that are higher than one that has to go from 1-6000RPM. Drive your car sportingly and you use more gas and more (not much) wear on the engine. I assume the same thing happens with an electric vehicle but one thing an electric motor can do that IC engine cannot is supply 100% torque at 0 RPM. Pretty cool. I bet if they eliminated the batteries and electric motor and used a four cylinder, it would get better mileage.
3) I had high hopes for the Volt but it just isn’t finished. The problem of charging times is there but a range equivalent to one gallon of gas makes zero sense. They made a lot of noise about super capacitors that could be charged quick, I haven’t heard that in a while. Like the article states, I think the battery technology is not there yet. I think the Tesla has over 6000 individual cells. Must be fun to wire.
4) All the talk about quicker charge times mean installing a high current box in your garage, I recall it was $3,000 and I don’t remember if the main breaker box has to be changed as well.
5) I do think it’s a good idea when all the technologies finally come together. I don’t like the rebate of what, $7,500? Do you know anyone with a Volt? I would like to hear what a normal commuter thinks of the car.
They also do it because gearing for such a beast would be a nightmare; electric motors have the ideal power curve for a locomotive because they deliver maximum torque at zero RPM.