Quote:
Originally Posted by Chance
If it takes 100 HP to power a motorhome at steady highway speed, then installing a “really small gas engine” to power alternators that then power electric motors would be very inefficient. A small engine would have to work much harder and would end up using more fuel.
Most motorhomes burn more of their fuel on the highway, not in city traffic where hybrids shine. And making matters worse is that many motorhomes don’t get driven enough miles annually to justify the higher initial cost based on fuel savings.
Hybrids make sense to me mainly as a means of recharging house batteries in minutes rather than hours. Fuel economy gains while driving isn’t going to make enough of a difference to justify added costs.
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On my C-Max when it would switch to "hybrid" mode (it was a plugin and thus had an extra 35 miles or so in the battery before switching to "hybrid") on the highway it wouldn't run the engine all the time. It would run the engine at its most optimal speed and charge up the battery to go a few miles (at the same time propelling the car). At some point it would shut off the gas engine and use the electric drive until the battery was depleted to some predetermined state.
Thus driving down the highway was a repeat cycle of gas engine running for a bit followed by electric only propulsion followed by gas engine etc. To eek out the highest mpg from the gas engine as possible (e.g. run it at its most efficient speed regardless of the vehicles speed).
Of course in winter on the highway it would just run the gas engine all the time for heat.
My preference would be for something more like the F-150's hybrid powertrain: An engine large enough to move the RV around that would only require a bit of boost now and then from the electric motor and include 10 or 20 kWh of battery that could be used while travelling or while parked to power the RV (and use the main engine to recharge it--pretty quickly).
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