Let me start by making this disclaimer: I will probably never be able to build this, and even if I could, its at least 10+ years off. I just want to enrich my mind and imagination by figuring out how it could be done. This would never be the cheapest or easiest, that's not the point. I enjoy the design and problem solving aspects of the build, driving it afterwards is just a bonus.
That being said, I want to figure out how to build a small rock buggy. I think I would want to use a hybrid ICE/electric/hydraulic powertrain. It would need to have enough low speed torque, and maybe have a top speed of say 30 mph. Fuel efficiency is not a primary concern, no matter what, 4x4's are always expensive to play with. I think with as little as I know about the specifics of regular hybrid technology, that I would like to run the ICE in series with the electric motor, primarily as a range extender. The electric motor would in turn power a hydraulic pump that would spin hydraulic wheel motors (mounted at the center of the axles). The two primary reasons to add hydraulics is because I feel these can be made survive harsher environments for cheaper than electric wheel motors. I also think that some clever valving could gain several features that might be nice to have in an offroad vehicle.
Perhaps I could try and complicate things by being able to bypass the electrics and run a hydraulic pump directly from the ICE as a sort of "limp mode", but I dont know how necessary that would be, nor how much more complicated it would be (or expensive).
Most of the questions I have pertain to electronics, but include a few other topics:
- Is regenerative braking something I should try and include?
- Aside from trying to recapture energy, can the electric motor be braked electronically?
- Are there motors available with that would allow me the low end torque and high speed without the use of a gearbox/transmission?
- Aside from weight, what are the primary benefits of using more advanced batteries than say AGM lead acid?
- If sticking with a series hybrid, what is the most efficient type of ICE, and what kind of power cycles should it see if all it is doing is basically running a generator?
- Anyway or reason to make the hydraulics do more than simply transmit the energy coming from the electric motor?
Some of the other details about this daydream:
- Smaller than a samurai, larger than a side by side
- two seater with tube chassis
- 33"-35" tires
- hydraulic valving to get park/reverse/neutral/forward
- homemade solid axles
- as quiet as possible
I am very open to different ways to build something like this, what might you do differently?