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Old 04-22-2022, 08:22 PM   #5 (permalink)
Master EcoModder
Join Date: Jan 2012
Location: MI, USA
Posts: 571

92 Camry - '92 Toyota Camry LE
Team Toyota
90 day: 26.81 mpg (US)

97 Corolla - '97 Toyota Corolla DX
Team Toyota
90 day: 30.1 mpg (US)

Red F250 - '95 Ford F250 XLT
90 day: 20.34 mpg (US)

Matrix - '04 Toyota Matrix XR
90 day: 31.86 mpg (US)

White Prius - '06 Toyota Prius Base
90 day: 48.54 mpg (US)
Thanks: 8
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I've done a touch of pulse and glide, it's a bit too active of a technique for me even though sometimes the roads are open enough to do it closer to my house. I live way out in the country so all roads are 55mph, in town it drops to 45mph for most of the roads. There's not much for 35mph and less besides really busy drives to stores and such. I messed around with that a tiny bit in my corolla, and from stopped to stopped, best I could get was around 60mpg while steady state I was able to get about 45-50mpg for the same area. My tank averages were 38-44 including winter driving, never quite hit 45mpg in a tank, but sometimes I couldn't drive for max mpg. I think my best trip steady state driving was 52mpg on the scan gauge.

The way I got good mpg in my corolla was keeping the engine rpm as low as possible basically, it was an automatic so I couldn't control the gearing myself. The prius seems to go too low gear for max mpg, it seems to want to really rev the engine. Based on that pic it looks like prime rpm for the engine is around 2000-3800 rpm. My corolla's peak torque was at 2800 rpm, and if I kept it in lockup the best mpg I could get was around 40-45mph (45mph is min to get lockup, it comes out about 40mph). I drove those speeds since I worked midnights and traffic was reasonable. Now there's a lot more section of the road that people can't pass now, dumb left turn lane that doesn't help much, but that's a different story lol.

Anyway, sounds like I'm driving the car almost exactly opposite from the ideal setup. I'll have to try driving on the engine more and see how that does. I guess for parking and leaving my drive way it makes sense to run on electric only, but once on the road I should be using the engine.

I figured the round trip efficiency from engine, to battery, back to electric motor was a bit better than 66%, I think that explains why my mpg seems low, just driving it wrong lol.

The coasting tip in the vid is a good one, I kind of had the thought that coasting w\o charging the battery and with the engine off was more ideal than charging the battery and shortening the coast distance.

I need to dig up my scan gauge some time, I have it around, but my last car I was driving is a 1990 so no OBD2 port. There's a check engine code set, I'm guessing it's for a misfire as it seems to have a very slight miss at idle. Under load it seems fine, got new plugs and such coming to see if that fixes it. If not I'll have to hook my scope up and see if any of the coils are starting to fail.

Anyway, thanks for the info and write up. Everything I was finding was basically drive like a grandma and coast as much as possible.

I mess around a bit with electronics and programming and such. For under 45mph, it might be good to do a minor pulse and glide, say 5mph speed range or so. I know more is more ideal but in traffic I think a 5mph change in speed would be acceptable. Would be interesting to intercept the accelerator pedal signal and automate the setup, set the "cruise" at the peak speed, and it drops to 40mph and speeds back up to 45mph automatically. Not sure if/when I'd have time to play around with it, but could be a fun little project.

It would be nice to be able to cost down from 55mph with out the engine spinning or the battery charging. Guessing putting the Prius in neutral isn't ideal while moving, but I haven't tried it either. That use case is pretty situational for me, if no one is behind me, I don't mind coating a farther distance, but if someone is behind me, I try to be reasonable on coasting, more than the average person, but less than ideal.
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