4 ms·
What about them makes them so inefficient?
by polishdude20 3y ago
What about them makes them so inefficient?
- bluGill 3y agoIf the torque converter doesn't have a lock that is a big loss. Those same transmissions also tend to have low efficiency hydraulic pumps internally to select the gears. Modern automatic transmissions tend to be much better than older ones.
- lloeki 3y ago> Modern automatic transmissions tend to be much better than older ones. I seem to recall improvements in that area around 2015 (probably driven by emissions regulations) but don't know the implementation details. One change was also a marked increase in available ratios (7, up to 10) which combined with better logic drives mpg down overall, sometimes lower than stick or dual clutch on standardised tests.
- lloeki 3y agoAutomotive gearboxes prime goal is to: a) expand the workable range of the IC engine (1000-5000rpm for Diesel, 1000-9000 - at best - for NA petrol, turbocharging dials it down) b) solve the zero-to-low rpm problem that causes stalling due to nonexistent torque It results in a complex device where many parts are still spinning even on the non-engaged gear. Look at a cut out of a manual transmission. The irony is that an epicyclic automatic transmission is mechanically efficient, up to the torque converter which uses fluid coupling. Efficiency is a secondary goal to the ones above, without which the car would be useless.