the crankshaft torque of the NA 3.8 litre Jaguar XK150S (a sportscar) was in 3rd gear at ....
(617 rpm) 10 mph 176 lb ft, 20 mph 186 lb ft, .... 40 mph 200 lb ft, 60 mph 209 lb ft, and (4936 rpm) 80 mph 211 lb ft
pretty close to constant torque
with a weak electric supercharger and F1-style control of ignition timing etc it could be dead constant torque
or even work nearer to constant power - a bit like an EV
the Paxman Hi-Dyne torque curve was notionally constant power throughout its working rpm range
(that range being limited by wheel slip - the lower range capability of the motor was not endorsed)
of course the locos were 'clutched' by a fluid coupling (non-torque multiplying)
the original diesel loco the (V4 reversible 2 stroke) Borsig-Sulzer Thermolokomotiv of 1912 had (rigid) direct drive
it ran by compressed air motor action to 7 kph - there commenced diesel motor action at maybe 100 rpm
even with normalised charge at 0 rpm torque would be less as heat addition would need to be later to contain pressure peak
torque could be maintained by increased charge and fuel - but necessary heat dilution would demand further charge increase
incipient resonance (surge) in path between motor and load could increase load and stall the vehicle
the EV design must also deal with some of these issues
Last edited by Tommy Cookers on Wed Jan 23, 2019 1:01 pm, edited 1 time in total.