Quote:
Originally Posted by Ecky
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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Lets go back a bit. Diesel electric locos have been around for decades, and they have successfully replaced every other railway system bar just a few speciality cases. The ethos they hold to is known as 'load balancing'. But what they are looking at is not only the loco, the whole track layout is designed to keep within the locos capabilities. The grades they encounter are designed for the train, the make up of a train is also designed to keep within those parameters.
What I would expect from an electric car would be to be able to accelerate like a banshee, but be more speed limited, not unreasonably so but quite far from 120 mph or unlimited autobahn speeds. The inclusion of the gen set is just to reduce battery weight and cost, and extend the range in ways we are all used to. As long as you feed the engine fuel, range is unlimited.
I remember Alek Issigonis saying of his brain child the Mini only needed around 5hp at 60mph to take care of the aerodynamic and frictional forces, and if you think about that you begin to realise how inefficient the IC engine power transmission system really is. I cant escape the feeling that depending on your driving needs, just going back to 'load balancing' should realise great gains in consumption in the order of 1.5 pounds of fuel per hour.
Thats around 0.2 of a gallon per hour, by a SFC for 5hp at .3 lbs per hp per hour. Achievable? .... frankly Ive no idea how much less performance that buys from what we have today or how much battery would be required to balance.