|I have examined many of the possible ways to incorporate an electric drive on the many varieties of SUV,Pickup, and Vans, and have itemized the issues that need to be resolved.
1. The vehicle operation as far as power steering, brakes,ABS,air bag,ac or heat, must be intact and operational, if this is to be safe and well accepted.
2. Since each car has differences in how these systems work, and are integrated with the control computers,it will be a major design effort to make a universal interface that would work smoothly with all of the variations that are used in the various vehicles from the various manufacturers.
3.a powerful electric drive system,is required to push a heavy vehicle,with lots of heavy batteries if highway speeds are to me maintained for any distance, which will likely make the system cost higher than people will tolerate.
A top speed of 45mph, and a design range of 20-60 miles, would keep the system size and cost down,with the range being a variable as to the battery capacity that would be installed.
I just did an experiment with my 1996 Dodge Caravan with the big 6 cylinder engine. I got on a slight down hill road,got up to 45 mph and simply put the vehicle in neutral, and watched the mpg gauge. I was getting about 75 MPG, as the engine idled, kept all safety systems operational as well as giving me the needed heat(was 48 F). If I had an E-drive(rear wheel powered), or E-wheel (hitch mounted drop down wheel), that could have maintained the 45 MPH,the trip would have yielded 75 MPG. If more power is required, simply put the van back in gear, and climb the hill or accelerate into traffic. All of the safety issues of running full electric are taken care of, and no modifications to the van were required.
A standard tranny would work even better.
If a DC/DC converter that could take the 12V system and charge the HV batteries, were included, a limited form of regen using the idling gas engine may be able to extend the electric range.
Of course the next step would be to add an interface to the brakes and power steering so the gas could be turned off. More costly more complexity, and more potential safety issues.
What would it look like:
The trailer hitch E-wheel would look like the rear end of a motorcycle, and have batteries over the wheel with shocks and springs supporting the weight. If more batteries are needed, they could be on board. I have a design in mind that would allow backing up without the need to lift the wheel, which would solve the biggest issue with the concept
The integrated E-drive would electrify the rear end, and always be available, this would be the cleanest and safest,but would be custom for each model.
A two wheel electric pusher trailer (Hybrad) would be an additional option.This option makes backing up difficult,but is easy to remove from one vehicle and put on another, or for storage.