The finer points of pulsing and gliding

How many miles is your commute?

 

If you're thinking about speeding up time to work, faster speeds with shorter glides or warp stealth mixed in can be good. Not as great mileage but still very good.

At 50 mph for example you can likely get 50 mpg instant. If you pulse gently there for .2 miles and then warp stealth for .1 miles, you're at 75 mpg. Then a nice and easy pulse around 50 mpg back to 50 mph, and repeat. A gentle pulse also serves to charge the battery more, which is better in this sort of thing, otherwise you'll draw too much on the battery. Con is that it's a lot of work to get the engine on, then fuel cut, engine on, etc.

Up a light hill, if you're at you're desired speed, usually the most practical thing with traffic is to hold that speed with as little gas as possible, which is usually surprisingly little unless your SOC is low. I used to try to pulse and glide up hills, all that happened was the battery got lower than I wanted. I have this gradual uphill that I used to see as an enemy, since it was relatively long and speed limits are slow (30 mph). Then I found that with bare minimum pedal, my car will start it around 35 mpg. It's so low because it's charging the battery a little extra at first. It stops doing that after holding the pedal steady for awhile, almost like it realizes I really do want to go that speed for awhile, and then it pops to 45 mpg. By the end of the hill I'm going 30 mph uphill getting 50 mpg. It's SHM for low speeds. So the car has the smarts for it with some patience.

With the mpg numbers so high over the course of the uphill, it has a very small effect on overall mpg, and the subsequent glide brings back the average really nicely. So that's my hill technique as of late. Slow and steady, engine on the whole time!

 

on hills. do not regen. if going down, take advantage of gravity to build AS MUCH SPEED as possible. this may require going above your target speed. use the momentum going back up the hill with a slight application of power to reduce the rate of deceleration.

 

OK just thought of something else...you're in flat Florida. At 50 mph just SHM that shiznit. You can get 70-75 mpg on flat ground with SHM while holding speed, assuming relatively smooth pavement, and Gen III is supposedly better than Gen II anyway at those speeds. Sometimes you might happen to drop below your allowable minimum speed (let's say 50), but I would avoid pulsing and SHM gliding, and rather aim to hold speed constantly with SHM, and just occasionally give a little extra if you get too slow by a mile per hour or so. Your state was created for the elderly and good mileage, it's the ideal situation, slow elderly drivers who won't tailgate you as you get good mileage

 

My commute is almost 17 miles one way, probably 40% 55 MPH, 20% 40 MPH, 40% 45 MPH, with lights and rolling hills. The hills provide good glide opportunities. I don't believe in gliding into or up a hill. I'd rather just maintain my momentum and start a glide as I crest the top. For the 55 MPH stretch, I can't seem to make anything work well other than holding speed with the lowest RPM I can.

I recently bought a ScanGauge as well, but I've mostly been using it as a tach. Prior to getting it, my best MPG for a trip to work was 62 MPG displayed, with an average speed of 30 MPH. I plateaued there and got it repeatedly. With the ScanGauge, I've been accelerating more briskly at ~1800 RPM, and my commute's MPG has gone down slightly to 60.x-61.x MPG displayed, with an increase in average speed to 33-35 MPH. My "pulses" are slightly more vigorous, and my resulting glides tend to be longer and at higher speeds (and often above the 45 MPH threshold). I'm pretty happy with that tradeoff, because that's a negligible increase in fuel consumption considering the difference in driving style.

 

Ya know ... when I first got my Prius, I was REALLY INTO the whole pulse and glide thing, and absolutely maximizing every single tenth of a mile per gallon, as if a tenth of a mile per gallon were something to be cursed at if you lost it. Go from 54.3 to 54.2 and I was like .... dammit ... I have to get that tenth back. I'd drive stupidly as long as there was no one around just to get that damn tenth of a MPG back. Lately though, I've just been driving it like it's a regular car, and I'm getting 50-52 without even TRYING to get max MPG.

Maximizing MPG is great fun, and it's always fun to gain a tenth or two, but lately I've just been relaxing and not obsessing on the MPG's, and it's a lot more fun to drive that way rather than going SLOOOOOOOOOW just to get the extra tenth here and there. I've gotten to the point where 50-52 MPG is good enough driving normally, and I'll forgo the 53 and change driving strictly for mileage. I STILL drive for mileage, but not as obsessively as I did when I first got the Prius. 50 MPG is still pretty good, and it seems like that's right about what my car will get on a normal daily basis. I still get about 57 on the highway.

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I find if I drive on local roads, I can't beat the red lights anyways, so it's best to modify my P&G patterns to time the red lights, although it seems people behind you get really annoyed if you don't race to the car stopped ahead of you only to slam on the brakes.

I found that SHM at 55 mph may not better than pulse & glide at that speed. If you try P&G around 50 - 55 mph you may still see MPGs climb. I find SHM is more effective at > 62 mph. If you speed up a bit beyond 55 mph and get into SHM you may find MPG may not suffer that much and you can still reach your destination faster.

 

Would someone please explain what SHM Super Highway Mode is exactly ?

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