Quote:
Originally Posted by P-hack
I'm not proposing that pusher except as a quick fix (though it is thoroughly robust and reliable), if you have a generator and charger and trailer laying about then why not try the generator approach? Some guys spent $75,000 on a generator powering a 1500lb $200,000 car and got 30-35mpg. Another guy spent a couple grand on a diesel rabbit pusher and got 25-30mpg behind a 3100lb rabbit.
I'm trying to comparing apples to apples, as well as one can, in terms of hypothetical innovative range extenders. Both can load/unload the engine with the battery, both have relatively independent speed vs rpm. Both are operated for maximum efficiency, both can downsize the engine. I don't see where the generator is going to be more efficient in locomotion, but lots of obvious cases where the pusher is.
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Comparing a commercially built genset along with a very unique handmade (and therefore rather expensive) EV to a self-built pusher with a run-of-the-mill production car converted to EV does not strike me as "apples-to-apples". I suspect that there are several on this board that could build a genset trailer for a production car EV conversion which can be as efficient (if not more efficient) than the 500cc gasoline Kawasaki motorcycle engine used with the tzero EV. And if they're already going to be DIY'ing the solution, then certainly they could drive the motors directly from the generator, making pulse&glide an interesting variation from an ICE counterpart... pulse using electric power generated directly from the genset and then (when gliding (without regen)) the genset can be charging the batt pack. Any time one would leave the ICE in gear when coasting (for DFCO), the EV can be using regen plus the genset for charging. Maybe (?) not as efficient as the ICE pusher, but I believe the range of options are there, just as they are for a pusher. And of course, as noted by
redpoint5, there's no reason the genset even needs to be on a trailer (depends on the owner's willingness to heft the components up to hitch height).
That's not to say a pusher couldn't also be improved over Mr. Sharkey's implementation. Right-sizing the engine, spring-loading the trailer to help with traction, making the trailer more aero and with lower rolling resistance, etc all could help in making that combination more efficient as well.
It really does depend on the EV owner's situation and skills (as
IamIan implies); I'm not seeing the obvious advantage of efficiency between a well built (and therefore better than gasoline motorcycle engine) genset (which is integrated as well as possible into the EV) and a well built pusher (which is integrated as well as possible into the EV).