It has been tried in the past .......

www.youtube.com/watch?v=rieFTJ7YrJE

Tilling-Stevens petrol-electric bus. Petrol engine drives generator which powers electric motor that drives wheels via a noisy single-speed gearbox.

Edited by Sofa Spud on 28/10/2015 at 23:54

What about CVTs? I remember when I bought my first car, a mid-90s Nissan Micra, that they offered it (and still do) with one, although after initial good reviews, many seemed to be developing terminal faults after about the 5-7 year mark - I wonder if the newer versions have improved long-term reliability so they last as long as the engines?

I have a Jazz CVT (with torque convertor post 2011). Imperceptible changes, ideal for town. No problems so far in three years and none expected.

EDIT: Honda schedule oil changes every 25,000 miles..

Edited by madf on 29/10/2015 at 11:58

I presume the reason that torque converters are less fuel efficient is that the converter is constantly churning fluid even when locked up.

Don't all gear boxes churn fluid? You could argue that it's stiffer to churn a manual box because the the oil is often thicker (unless it uses ATF).

Any slight reduction in fuel efficiency is more than compensated for by better engine protection and no clutch plate/hydraulics/cable problems, quite apart from the ease of driving. Millions of Americans can't be wrong, although.....

Thanks for your comments.
As I said in my original post, I was relating to small cars.
Most non torque converter systems usually seem to have robotised manual boxes which appear to attract the most critism.
I presume the reason that torque converters are less fuel efficient is that the converter is constantly churning fluid even when locked up.

Modern torque convertors lock up and don't churn after a certain speed has been reached - and have done so for at least 15 years...

Thanks for your comments.
As I said in my original post, I was relating to small cars.
Most non torque converter systems usually seem to have robotised manual boxes which appear to attract the most critism.
I presume the reason that torque converters are less fuel efficient is that the converter is constantly churning fluid even when locked up.
My thoughts behind using the electric motor is that it would not absorb power after the initial start, and could even replace bottom gear.
I have assumed the normal automatic epicyclic gearbox would be retained.

If one has electric drive, like on the old petrol-electric bus in the video I linked to earlier in the thread, a single gear ratio would be sufficient to take the vehicle from standstill to top speed. The engine would only drive a generator and would work at the speed needed to produce adequate current, independent of the vehicle's speed. This is how the majority of diesel railway locomotives work .... diesel engine drives generator that powers electric traction motors on the axles. No need for any multi-ratio epicyclic gearbox, just the single reduction gear between the motor(s) and wheels.