[P-hack]

Originally Posted by IamIan

@P-hack:
I don't know why you continue to try and defend the one sided biased ... any situation position ? ... it's incorrect.

I'm not saying pusher is better in terms of deflecting asteroids, or has more utility post apocalypse, I am talking about peak and overall efficiency, i.e. for long trips (or stop and go if designed for it). A good range extender should be treated like any other ecomod and get mpg similar to a vehicle with the same weight,rr,cda and why not enable hypermiling the pusher as the situation allows.

The auto-pushers are not examples of good ones in the efficiency sense, but they are superbly cost-effective and simple. But they are heavy and use oversized engines for the job of cruising, and etc. Since they are shortened cars (complete with alternator).

But the state of the art of electronics and motors and generators does not compare with mechanical linkages in terms of efficiently transmitting power to the wheels. Thus the more power flows directly to the wheels (efficiently) the more efficient the system. This is true at any reasonable speed. And a handful of gears is enough to keep the engine in the target efficiency rpm range, and the battery can load the engine while moving, again if that actually helps vs the losses "regen" incurs, the series is basically regen always except when demand = generator output.

Originally Posted by IamIan

Depending on the situation the pusher might be better ... and in different situations the generator will be better ... what is so bad about it depending on the situation?

Series only is good when stopped (taking a wiz), and that is basically idling, which is not a good efficiency strategy, ever.

Originally Posted by IamIan

Past a certain point in the BSFC the Pusher reaches a lower minimum efficiency from tank to road.

The options a generator has are to A. deplete the pack to keep the engine near bsfc, or B. go past bsfc (and upsize the generator). The pusher can also be locked via ratio/rpm selection and have the battery assist, or if the battery is dead as in your scenario, the pusher will have more power available beyond bsfc in a pinch. Peak bsfc is not peak horsepower, but we are talking about having let the pack run down completely. There is nothing inherently different about pusher vs generator except that a well engineered pusher has greater efficiency overall, not just peak.

Originally Posted by IamIan

This is true to either more power or less power.

true for the pusher as well as the generator, both have engine loading/unloading, rpm control strategy at their disposal.

Originally Posted by IamIan

Adding alternator to Pusher = Combined Pusher / Generator.

Thus it admits the situation where the generator is better than just the pusher.

I think some of both is best, but "mostly pusher" for efficiency. I'm kind of assuming that an EV with AC has electric AC and that a pusher (or generator) should handle lights/fans/whatnot. Of course the EV can work with the pusher and just use regen (hopefully efficient regen) to keep the battery from depleting completely. Some knowledge of your situation is essential for hypermiling such a system too. It is best to use what battery power you have even on a long trip, assuming you can recharge at your destination.

Originally Posted by IamIan

... it could be the pusher ... or it could be the generator.

I don't see how the generator is going to come out ahead in efficiency with so many losses in just getting the power to the wheels, and with no special techniques that are not also available to a pusher.

Originally Posted by IamIan

But that doesn't effect the far more wide claim you made in Post #198 and continue to try and defend

The situation is which is most efficient, that is all, which will turn the fuel in to miles covered being the best. Talking about powering a house isn't relevant. Because I can make up scenarios where you need to leave the house powered and leave with the car too.

Originally Posted by IamIan

All the wheel power the pusher makes will be limited to the friction it has from the 1,100 pound down force ... that was the weight of the pusher trailer referenced earlier in this thread.

Either way there will be more motive traction than a front wheel drive EV has by itself. But if you need more traction, spring load the pusher (or better yet, hydraulically add down force on demand), or move the weight forward (and add appropriate sway damping), or make it integral to the EV like putting a generator in the trunk.

Originally Posted by IamIan

The higher down force of the 3,100 pound BEV

you ignored some rather obvious solutions if it is even a problem for most people. Would like to focus on normal driving, not rock crawling either, like the 15,000 miles on roads that normal people use. Like so many SUVs that will never go offroad as much as my prius does. Determining "need" based on extremes is kinda futile. The t-zero is front wheel drive and would benefit from a push from the rear up this "slippery slope" anyway.

Originally Posted by IamIan

#5> Pusher referenced = Increased Rolling Resistance
This does bring up another good point though ... the pusher trailer is heavier

not an example of a good pusher for efficiency. A pusher that does not have all the efficiency losses of the generator system can have a smaller engine, and does not need a large generator (though a gearbox would be nice for efficiency at sub-hiway speeds), and it can carry less fuel for the same range.

Originally Posted by IamIan

In this case ... the proposed pusher

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.

Given how many EV's don't even have a gearbox, or even a neutral, I get the "dirty hands" feeling this must give you to even consider it, but physics are physics and our imaginations should not be limited by preconceptions.