How to get Better Gas Mileage

Flywheels... Seems to me that there may be buses on the road today using them just as the Prius uses a battery. The Prius engine is very efficient at speed, but has such poor torque that alone it would provide unacceptable acceleration from zero. The battery just fills in that gap, hence its limited capacity (a third of a cup of gasoline). Some flywheel systems work similarly - augmenting the engine.

But when I was a young engineer in the vacuum tube days, there was a Swiss bus that ran entirely on a flywheel, which was re-spun periodically along the route. It drove a generator, which powered motors, which ran the bus.

Jetson transport is unlikely, since personal transport of that sort needs an energy equation that is unlikely to be satisfied with batteries, and carbon-based fuel will probably run out before the personal air transport is perfected.

Reply to
notaguru
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The battery does more, actually.

And Toyota did a fabulous job with their Power Split Device to replace the transmission.

Overall, Toyota's HSD is an amazing piece of technology. It's more than just "stick a battery in there" like what Honda did.

Reply to
Elmo P. Shagnasty

And is more fun to drive, too.

Reply to
RRB

I will try to maximize the glide time of the Prius and I've considered whether rapid or gradual acceleration is best to get back into gliding. Intuition suggests that if I rapidly accelerate I can get back to gliding more quickly, but the problem arises that I never have any opportunity to regenerate the battery doing it this way. Eventually the engine will start during the glide just do maintain SOC.

Lately I've been accelerating more slowly from the bottom of a glide. A rapid acceleration will actually drain the battery further, so I go for a slower acceleration where I can see the excess energy flowing into the battery. This lets me have more uninterrupted glides, with slightly longer pulses in between.

I've also plotted separate courses to- and from- work. The route to work is residential streets when the engine is cooler from the night. The engine will be running anyway to heat the exhaust system. I use that time to charge up the battery. For the last two miles I have found a 30mph road that is excellent for gliding. I head into work very efficiently and use up the charge I have accumulated.

On the way home the car is usually hot from the daytime sun and so I'll take the highway. The car doesn't need to do much to heat the exhaust system. I can get gliding quickly before entering the highway. The engine won't ever shut down at 60-70mph, but I can still maintain long stretches of 70+mph because the roads are agreeable (and apparently downhill). When the occasional congestion arises, I'm taking the shortest path home and I'm running all electric on the highway at 5-20mph. I usually exit the highway will a high charge and I can glide the residential streets home, attempting to use that charge up before I park for the night.

I would like to install an EV button for the ins and outs of the neighborhood. I'd like to start my drive with a low state of charge since I'm going to be charging it en-route. If I could just get in/ out of my subdivision on total electric, I think that would really boost my economy. I hate starting a drive with a full battery. The necessary engine operation has nowhere to store all its excess energy and I suspect that it is wasted.

Brian Herbert Withun

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Reply to
Brian

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