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Old 08-01-2017, 03:19 AM   #74 (permalink)
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Originally Posted by sidecar View Post
Ive always thought that a small continuous diesel generator, say around 3 to 4k watt and a battery bank to absorb undulations in power would be a good way to go. Possibly harder on battery though. Still if I had to start over Id be looking to go that road.

But I digress, depending on where you are driving the engine stops and starts frequently. In more undulating country driving engine off downhill, and whenever you stop. At other times you can see the engine is doing relatively little work to contribute to maintaining cruise speed.

Rolling around car parks on battery only scaring the crap out of people just doesn't get old.
Honda's latest hybrids do just this, but with extremely efficient gas engines - that's how the Accord hybrid works, and the soon-to-market clarity. By just using the engine as a generator, with a battery as a buffer, you can always run it at its most efficient RPM and load, giving it practically diesel efficiency due to leaving the throttle plate wide open and running Atkinson cycle.

However, the engineers also realized there are certain circumstances where the engine would deliver better economy if directly connected to the wheels, since there are conversion losses when going room mechanical to electrical, then back to mechanical energy. So, Honda also put in a light weight fixed single-speed clutched gear, allowing direct drive when the car is at the right speeds.

Reviewers were seeing in excess of 80mpg in lower speed driving conditions.
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