I worked on a hybrid electric car in the 70’s Unfortunately we could not get anyone even interested in the idea. The mechanical laws of physics remain the same, and I am still confused why our concept has never been implemented.
A little science.
The average amount of horsepower required by a 3000# automobile is only about 20hp. The high horsepower is needed to accelerate (ideally fast!) and go up long hills. Cruising only uses enough power to overcome friction and wind resistance. The problem with internal combustion engines is it is difficult to get uniform efficiency over a horsepower range of 20-300hp. On the other hand gasoline has a very high amount of energy per pound.
Electric cars on the other hand are very interesting. They can be designed to accelerate like crazy and batteries can provide a wide range of KWH output. The drawback is they need recharging. Also batteries weigh a lot, so you have to lug around a lot of weight if you want to have any range. Of course lastly, you can’t instantly recharge these things, and I doubt we are going to put in a huge infrastructure to do recharging at workplaces, malls, parking lots, side of the road etc.
Enter the hybrid of today. These make no sense to me. You have to have an incredibly complex mechanical system that is able to hand off power between electric drive and gas drive. On the other hand, the electric part give a great assist in acceleration lowering the need for a big motor. Also, this helps them become more efficient at cruising speeds.
Our original vision was for an electric car. Being based in San Carlos Ca. our mission was to be able to drive to Lake Tahoe. This is an incredibly daunting challenge but on paper it seemed possible as the first half is flat. The way the car was designed it was all electric drive. We even played with optical shaft encoders on the steering wheel rather than mechanical linkage. The idea was to shift power to the electric motors which were mounted on the wheels.
Magnet technology has come a long long way since then. Back then eddy currents melted electric motors when run at high output. We made a design with hollow copper wires so we could pump coolant through the motor. We inverted the design so magnets rotated but the windings didn’t so it was easier to cool. We got 100hp out of a motor mounted on the wheels. It was no problem to "smoke the tires". It worked. It would be interesting to revisit this in light of current magnet technology.
We then mounted a 20 hp gas powered generator, in addition to a bunch of batteries. The idea was this motor could run very efficiently at constant speed. And it was quiet!. In our mind it was a race between draining the batteries and having to stop or using a bigger generator. The great thing was the generator ran while you stopped. So if you stopped to get a Coke or a rest stop it was recharging the batteries while you were stopped as well. It turned itself off when the batteries were charged, and started automatically when they needed charging. The beauty was if you did run out of juice all you had to do was stop and wait a while before you could go again. Range was determined by how much weight you wanted to carry. We only carried 5 gallons of gas. Around town this car would have been awesome. Unfortunately, we never got to try to make Lake Tahoe before we ran out of personal money. Needless to say, this design would be very clean to operate. These days 20 hp generators that operate on either natural gas or gasoline or diesel are readily available. Of course regenerative braking helps keep the batteries charged as well.
I write this in the hope someone seems some merit and steals the idea. I always say, ideas are cheap, it is the execution that makes the difference.