EV Pusher Trailers

[Fledermaus]

Why a Hybrid Trailer?
As anyone involved with EV's knows RANGE is the one central problem (combined with slow re-charge times.) Traditional EV's all have ranges between 25-110 miles (homebuilt to optimized production.) Recharge times can be as low as 1-3 hours with high capacity chargers. But these range/charge times still do not allow long-distance freeway travel on the occassions when it is needed.

The idea of the pusher trailer and/or generator trailer is to give the normal EV long-range capability with fast fuel stops without permanantly installing an IC hybrid system in the vehicle. This saves the weight, and complexity, of having the IC engine with you (in the EV) for the 80+% of driving that is done within the EV's normal range. For long-range operation, the IC engine will take over all of the load and battery drain will cease or slowly reverse.

Generator vs. Pusher (Series vs. Parallel hybrid)
The "normal" approach to hybrid trailers (if there is one) is to have an IC engine driving a generator that sends electricity forward to the EV to supply the energy needed for highway cruising.

Click to See ---> AC Propulsion's hybrid generator trailer

Generator benefits:

* Energy can be stored in the batteries when IC output is greater than needed.
* The IC load is very level as the generator output can be nearly constant.
* No transmission is needed
* Standard trailer dynamics apply

However, this approach suffers from the inherent problem that the energy is transformed from mechanical (at the IC shaft) into electrical, and then back to mechanical (at the EV motor.) The energy will in the best case go through the generator, EV motor controller, and EV motor. In the worst case it will also cycle in and out of the batteries. All of these conversions deal a serious blow to the best efficiency possible. For a typical EV system you will need between 1/2 and 2/3 of the IC horsepower to simply push the car as you will to generate enough electricity to drive it.

Pusher Benefits:

* Fewer energy conversions Chemical--->Themal--->Mechanical
* Less IC horsepower needed
* Potentially lighter than a gen. trailer (smaller generator, less fuel, less IC hp)
* EV system does not need to be sized for continuous use
* Cheaper (no generator, more standard automotive parts)


The hybrid trailer in general only makes sense for long distance freeway travel (roughly greater than 50 miles.) The trailer efficiency will fall at slower speeds since the IC output must be cycled through the batteries or throttled back in the case of the pusher. In addition, urban driving raises the obvious problem of parking with the trailer in congested areas.

http://www.jstraubel.com/EVpusher/EVpusher2.htm

[Mnpaul]

1. I would rather have it all in one car

Bring on the Twin Drive


122hp turbodiesel drives the front wheels
82hp electric drives the rear

Both can be used at the same time for 174hp 4 wheel drive

30 miles on electric. Can be charged from the outlet, from the motor and from regenerative braking.

Up to 94.1 mpg acccording to VW
http://www.motorauthority.com/volkswagen-g...-in-hybrid.html
http://jalopnik.com/397242/vw-golf-twin-dr...us-look-thirsty
http://www.autobloggreen.com/2008/10/21/br...e-94-1-mpg-u-s/

20 are now being tested in Germany