40 miles
40 miles on battery power alone isn't so bad. People living in urban or suburban areas mostly make round trips of 10 miles or less.
I expect that the Renegade's battery pack can be recharged from a 110V or 220V AC circuit in your garage. So you can plug in when you return home, and be ready to go the next morning.
The trade-off for longer trips, of course, is the weight of the batteries. That's where the internal combustion engine comes in. The difference in this design is that, unlike the Prius and other hybrid cars of today, the Renegade's diesel engine doesn't drive the wheels. It powers a generator that takes over for the batteries.
Diesel-electric hybrids are not a new idea. It's the system that powers modern locomotives and those super large capacity haul trucks used in open pit mining. Electric motors are useful in these applications because they can be scaled up to just about any size, and they produce maximum torque at zero RPM -- Just the ticket to get a mile-long freight train moving.
The question to ask is whether an electric drivetrain makes sense for a Jeep. There is lots of low speed torque for off-road obstacles, and having two electric motors means you can make it home if you have trouble with one. The electric motors also work to slow the vehicle, so mechanical brakes don't have to be as large. Extra care would have to be given to waterproofing the motors for water crossings, but once properly sealed, the electric motor could power you across a water obstacle without the need for snorkle or raised engine exhaust outlet.
This type of diesel-electric hybrid doesn't need a transmission, since the electric motors can run from stop to the Jeep's top speed without the help of gear ratios. I'm curious why Jeep added a mechanical low range to the Renegade. Perhaps it allows the electric motors to be smaller, lighter and more efficient in use of battery power.
The US military is experimenting with vehicles that have electric motors at each wheel. This means no axles or drive shafts. You could create the effect of a mechanical locker by electronically matching the RPM of the wheels on opposite sides of the truck. The military likes how quiet the electric vehicle is and how low its heat signature is when running on battery power.
Chip Haven
