Sometimes I can run 35- 40 mph on the traction motor but??

You cannot glide and maintain speed. The definition of a glide is using no engine and no battery power. With no power you are going to lose speed unless traveling downhill.

Pulse and Glide is used in sequence to increase overall mpg for that stretch of road compared to constant throttle input. You are supposed to pulse up to say 42mph then glide (HSI indicator disappears) to 25mph or whatever speed works for you. If you have a 1 mile section of road the pulse section needs to be approx. 1/4mile or less and the glide section needs to be 1/2mile or longer for this to be effective. If you pulse at approx. 30 iMPG for the 1/4 mile then glide at infinite iMPG for 3/4 of the rest of the mile then you just got 90mpg average for that 1mile. Pulse and Glide can be used between stop lights and stop signs in low traffic areas, especially residential. It does not work in congested areas with lots of traffic for obvious reasons. So use it occasionally to mitigate other areas of your commute where you got terrible mpg. This is why all freeway off ramps should be used as areas to glide or warp stealth. It's free mpg!

In simple terms, if you see a stop sign ahead and no one is behind you then lift off the throttle, reapply a little pressure to disengage regen braking but keep the HSI indicator blank and glide to the stop. This can easily be done for a 1/4mile. Do this often enough over the course of a full tank and you just increased you mpg by 3 or more.

 

55mpg calculated is WELL above the EPA rating so you are doing great IMO. Even getting 49mpg with the AC on is great. Don't be so hard on yourself. Just keep working on techniques and finding ones that work well for your particular commute and are safe to employ. Try keeping your car cool so as to avoid heavy AC use and just use it for air filtering (recirculating mode perhaps). Keep the temp setting high for reduced mpg impact and use Eco Mode. Do all of the other basic things like checking tire pressure and driving without brakes and you'll be fine.

Some people have perfect commutes that favor hybrids. I drive 100+miles a day so I only suffer the warmup penalty 12-15times over the course of a 500-600mile tank. Someone with a much shorter commute could easily suffer double the number of warmup times that I do. That means they spend more of their miles at a lower mpg number because they spend more miles warming up. So despite my commute being 90% highway I still get great numbers. So just because your numbers are not as high as someone else's do not be ashamed of yours. Some of us work too hard on the numbers and/or are blessed with an accommodating commute. I'm a hypermiling noob so you can guess which category I fall into.

 

*Cough*

 

Ok ok, I tried to dumb it down to keep things simple. Sheesh.

Here is the basic formula.

Pulse distance * [(Target FE mpg/Average Pulse Rate in mpg) – 1] = Glide distance needed to achieve target.

From Wayne Gerdes.


Why does P&G actually work? P&G is not just about a speed range nor is it about an acceleration rate. It is a combination of a given amount of fuel consumed and distance traveled in the “Pulse” phase vs. the distance traveled in the “Glide” phase. If you “Pulse” for .3 miles at 35 mpg, you need to “Glide” at least twice the distance covered during the “Pulse” (.6 miles) to achieve 105 mpg average over .9 miles. When “P&G” is broken down to its component parts and reassembled, you simply have to accelerate for a given distance at a given consumption rate (“Pulse”) and coast (“Glide”) for an extended distance to cover the Pulse’s fuel consumption to achieve a given FE. Here are a few examples:

The following equation will show you what you will need to achieve for a given target FE.

Pulse distance * [(Target FE mpg/Average Pulse Rate in mpg) – 1] = Glide distance needed to achieve target.

For a 100 mpg target goal, the following equation and examples of differing Pulse rates (Average FE during the Pulse) will give you your glide distances needed to achieve your 100 mpg goal!

Pulse Distance (miles) * [(100 mpg/20 mpg) – 1)] = Glide Distance (miles) needed to achieve target.

Pulse at a 20 mpg rate of acceleration over .2 miles:
.2 miles * [(100 mpg/20 mpg) – 1] = .8 miles of Glide to achieve 100 mpg over a total distance of 1 mile.
.2 miles of Pulse at a 20 mpg pulse rate with .8 miles of Glide will give you a 100 mpg.

Pulse at a 30 mpg rate of acceleration over .3 miles:
.3 miles * [(100 mpg/30 mpg) – 1] = .7 miles of Glide to achieve 100 mpg over a total distance of 1 mile.
.3 miles of Pulse at a 30 mpg pulse rate with .7 miles of Glide will give you 100 mpg.

Pulse at a 40 mpg rate of acceleration over .3 miles:
.3 miles * [(100 mpg/40 mpg) – 1] = .45 miles of Glide to achieve 100 mpg over a total distance of .75 miles.
.3 miles of Pulse at a 40 mpg pulse rate acceleration with .75 miles of Glide will give you 100 mpg.

Pulse at a 50 mpg rate of acceleration over .4 miles:
.4 miles * [(100 mpg/50 mpg) – 1] = .4 miles of Glide to achieve 100 mpg over a total distance of .8 miles.
.4 miles of Pulse at a 50 mpg pulse rate with .4 miles of Glide will give you 100 mpg.

 

Yup, during the school year, I have a lot of short trips taking kids to school and my numbers are somewhat lower for that and then compounded by winter temps, too.

Keeping the ICE off is the biggest factor for exceeding EPA numbers that we've found, but all the other tips help, too. Perfecting Pulse & Glide or Pulse & Coast (when batt is low) and cruising on EV when appropriate are cruicial.

We easily get 65mpg+ on the highway with the Prius if we stay at the speed limit, but only in the low to mid 50s around the suburbs. We're not pros, but use the basic techniques. On the flip side, I do better around the suburbs with my Highlander Hybrid and not quite as well on the highway. Guessing because of the aerodynamics and also because the HL seems to be able to cruise on electric for quite a bit farther at 30-40 mph than the Prius can.

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Dumb question maybe, but if you are going to be stopping, why not coast and regen the battery? Is it because gentle braking is more efficient to regen the traction batt? If so, that's another trick I can use.

Yeah no kidding. I have a power electronics/machinery background and doing the math still takes the fun out of it lol.

 

If you are in regen then you are slowing down faster than if you were gliding thus you could have lifted off the throttle sooner and glided further and used less energy. Eventually you will have to apply the brakes and you will get a little regen out of that so I wouldn't worry about regen braking as a priority. The priority should be easy acceleration to a steady state driving mode then anticipating your stop well ahead of time so you can enter a glide as soon as possible and glide for as long as possible. This uses less energy than staying on the throttle longer then using regen to recover energy. Conversion losses remember? If done correctly, even using EV power to accelerate to 15mph you should still be able to recover lost energy by the next stop.

 

Oh I see what you are saying now, sorry for the confusion. Of course, it all depends how far in advance that you know you will need to stop as to whether you choose to coast or glide immediately. I thought it might have been some trick I didn't know regarding braking vs. coasting efficiency for recharging.

Edit: hey I just noticed you traded in your sweet mod Prius for a new one- congrats!

 

Nah, you know the tricks. For those times when you cannot plan so far ahead then use regen as much as possible.

Thanks! This new beast gets much better mileage once I figured out how to drive it!