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User Info Is Tesla On The Verge of Bankruptcy?; entered at 2017-11-21 09:50:19
Posts: 150727
Registered: 2007-06-26
my proposal was to use a gasoline or diesel engine or some other ICE operating at peak volumetric efficiency generating the electricity in the car itself and eliminate the ATX and mechanical drive train. marine propulsion as well as rail transportation has used diesel electric for close to a century. electric motors have full torque at 0 RPM. my experience as a marine pilot is that these are some of the most efficient and controllable setups available.

Diesel-Electric locomotives use it due to the zero-RPM torque capabilities, which means no transmission requirement, and at the power levels involved that's a big deal. In addition you have regenerative braking (dumped to a HUGE load resistor) for "free" from such a set-up.

It is only used in marine applications where there are very large house loads. Direct shaft drive is MUCH more efficient otherwise. You will find exactly ZERO container ships, for example, running D/E. Cruise ships are all D/E because most of the time a huge amount of their energy requirement is to run the hotel, and that load varies a lot with time of day.

The problem is the additional conversions; every conversion of energy costs you some of the input; it cannot be avoided. In the case of a car running all the conversion through the battery makes no sense, which is why nobody does it.

Some years ago I toyed with the idea of converting one of my vehicles to electric drive That part is actually not very hard; you remove engine and gearbox and find an electric motor that will couple to the output of same at appropriate RPMs. The idea was to run batteries for "local" use but have a small trailer you could tow that had a generator on it for longer trips, making it unlimited-range when needed or wanted.

The calcs said it wasn't worth it. The conversion losses on steady-state operation once the battery was discharged made it a material lose over just coupling the engine to the driveline.

That's why all the existing "hybrids" operate on that model.
2017-11-21 09:50:19