The ideas below have been posted on many threads, by many members. But now that many now have had more BEV experience and winter is here (I may get to try out my LEAF in the snow for the first time here in North California, tomorrow) I thought maybe there would be interest in a dedicated thread.
I’m still not so ready to totally write off the ICE, as many on this site seem to be.
In fact, a true ICE ”range extender” for a BEV is not a bad Idea, It's just that current designs are all abysmal failures, from the point of energy efficiency and driver utility. Putting an ICE drivetrain in an EV, whether in series, parallel, or any other hybrid configuration, is not advisable, IMO. Invariably, you will get an overweight, overpriced, underperforming vehicle, like the Volt. It seems almost as ridiculous, to install an extremely expensive and heavy large battery pack (like the Tesla S long-range options) which is only occasionally required by the BEV driver.
A functional range extender would consist of:
A small displacement (200-600 CC) ICE generator, run at highest-efficiency rpm, to recharge the battery pack. Generator output would not be sufficient to drive the vehicle, just enough to extend the battery pack range to the next convenient recharge location.
It would not run on gasoline, but a less polluting, and more stable fuel, such as propane (easier refueling) or CNG (lower cost). 5 gallons of Propane, for example, would probably offer about 200 miles of range extention for a LEAF-sized BEV.
The fuel would also be available to a combustion cabin heater, the one use for which battery energy storage is particularly inefficient.
I think this could be integrated into the design of BEVs (and maybe even as a portable unit, and available for rent, as many have fantasized) at lower cost, and lower weight, than the huge battery packs some BEV manufactures seem to think are advisable.
So, say you are a San Francisco Bay Area resident. You usually keep the heater set to propane by default in the winter, extending the range by about 10% and reducing battery cycling accordingly, without even using the ICE feature. You refill the 5 gallon propane tank once a month or so, just to supply the heater.
When you want to take the BEV on the occasional longer drive, say to Tahoe for a weekend of skiing, instead of making 3 or 4 stops (with a 20-30 available kWh battery pack) for DC charges, you just turn on the ICE generator during your trip, as soon as your battery capacity drops to a level to efficiently accept charge, while you and your passengers are kept toasty warm by the propane heater. You stop for one 30 minute 80% DC charge at Auburn (120 miles in 2 hours of driving, about 20 kWh consumed from the battery pack, and 16 kWh used from the generator) and top-off the propane tank (you only used a few gallons) at the adjacent minimart. This is just enough generator-assisted charge to get you the last 80 miles over Donner Summit to your destination, but you never get “range anxiety" (or BEV "freeze anxiety" about road closures or delays, due to weather) as you know that if you get the “very low battery” warning, you can just pull off the road, and if there is no charge station (or only a L2) nearby, you can always find a place to stop for a short break, while you self-recharge for the last few miles, using your generator. And if you get stuck behind a semi that jackknifed in a snowstorm, closing the road, you can watch the generator add bars to your battery, as the propane heater keeps you and your passenger comfortable, while you wait for the road to be cleared.
I believe BMW may be the only manufacture currently contemplating this true ICE “range extender” option, for its BEVs.
Personally, I believe that the several thousand dollars (?) of increased cost, and few dozen gallons of fossil fuel I would use per year, might be an acceptable price to pay for the increased functionality. I hope that, in the near future, there will be many production "EREVs" worth considering.
Last edited by edatoakrun
on Tue Jan 31, 2012 1:21 pm, edited 1 time in total.
no condition is permanent