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The Fun of Boring and Efficient

Energy Screen of Prius II MFD : Used in Hypermiling a Prius
I have often described to others how I find automatic transmissions boring to the point of tears: especially that awkwardly silent CVT powersplit setup in my Prius. Here I explore some of the fun hypermiling techniques that a Prius driver can "enjoy" to replace the fun they lost by not being part of the gear changing process....

While the automatic continuously variable transmission in a Prius might create a boring disconnected driving experience, that boring transmission setup does free up one to play fuel miser hypermiling techniques to milk each gallon of mostly imported unsustainable fossil fuel for as much forward motion as possible.

Hypermiling Techniques (shifting fun alternatives)

"Pulse and Glide" this is where you soft foot the accelerator for about 1MPH/ sec gain until you reach 5MPH above the posted speed limit (unless you are in a school zone or other low speed high hazard area), then you lift off the accelerator and very gently press back down on it to the 0 arrow screen of the MFD (prius specific user info), where the Prius enters auto-coast mode (glide), when you allow the vehicle to slowly decelerate back to the posted speed and low to whatever speed is practical around 28MPH. This works exceeding well on gently rolling hills with a 45MPH speed limit. 

"Gentle Foot" The prius's electronic throttle computer calculates what combination of electric motors and gas engine RPM to use based on the throttle position sensor and rate of throttle position sensor change. By Gently accelerating (around 1MPH / second) you help this computer to produce the optimum ration of power generation for exceedingly efficient fuel use. 

"Early Soft-Brake/ Regen maximization", this is where you preemptively anticipate an upcoming stop several hundred feet in advance, and gently apply the breaks softly so as to allow MG1 and MG2 to regen the most amount of electricity without using your mechanical brakes at all. This can be then combined carefully with "catch the light"

"Catch the light" is where you slow down so as to still be moving when the next signal allows you to go, and that includes taking into account how many vehicles are stopped at the signal in front of yours and estimating how fast they will accelerate. This works equally well in conventional non-hybrid vehicles.

"Wave Cancel" in heavy traffic you slow down to 2, 3, 4, 5, 6, 7, 8 or whatever really low MPH speed needed to avoid stopping and starting constantly: this can save your leg/ clutch in a manual vehicle: if you are careful to observe this, you will not that large trucks do that as a general practice. This also works really well in almost any vehicle. This is known as wave canceling in physics. Stop and go traffic formations can be viewed as "Standing Waves", where wave cancel seeks to cancer out the dips and crests (stops and starts). This requires leaving a buffer zone infront of your car, and do not be surprised if a bunch of impatient rude morons cut you off because they see and opening in front of your car (your buffer zone), when that happens, slow down even more to create another buffer and then enjoy watching the tool that cut you off mashing their pedals back and forth ( as you coast along nicely wave canceling behind them) : don't get smug about it either, your not that special! Everyone is Equal in Gods eyes... with wave canceling you do get to enjoy a car that costs less to operate because wave canceling reduces wear and tear on your car and also boosts your fuel economy!

"Corning dubbing" where you coast in neutral deceleration ahead of a known corner such that you reach the safe cornering speed by the time you get to the corner. This is a Prius specific move designed to take advantage of the vehicles forward momentum in the glide mode.

"Hill Speed Jockying" where you gently accelerate to above the speed limit on when approaching a hill, and then back of the throttle to allow you vehicle to decelerate down to slightly below the speed limit as you crest the hill: followed by a "Gen Max Soft Brake" to collect as much juice on the way back down. This is another Prius specific maneuver.

These tips and tricks are designed to maximize fuel economy in a Prius, and they can also be seen as fun, since they require technique and thought to execute effectively. People that frequently hipermile their Prii also frequently get 55+ MPG's real world: some that do so in warm temperate flatter regions can average north of 75 real world MPG's.

I mostly lightly hypermile, to the point where it became part of my driving habits: my favorites are "Catch the light"  and "Wave Cancel" Unfortunately, my lifetime average is only 46.4MPG's: I live on top of a mountain, so every time I drive home the hill climb ruins my fuel economy averages. In a flat region, like parts of LA, I was able to easily average 75+ MPG's using my techniques.... Snowboarding trips also took their toll as the mountain pass adventures are also fuel hogs, typically only averaging 40MPG to snoqualmie and back, which I did over 500 times during college (season pass every year/ student discount)

I should make perfectly clear that hypermiling is mentally demanding, and should only be attempted by non-distracted drivers with the faculties and abilities to do so safely. Even where hypermiling is executed by a competent and capable driver, it still carries intrinsic risks that need to be carefully considered. 

That said, when you are driving, focus on driving!
You can focus on other things when you arrive at your destination!

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Astro is my Prius : I am Drumsmack


  1. Great information. In an ordinary manual shifted ICE, I practice pulse and glide on windy roads (pulse out of a turn and coast into the next one), wave cancel in stop and go, and to a lesser degree catch the light.

    Also, when not overdone, techniques like wave cancel can actually make driving safer. It would be interesting to write a traffic simulation that incorporates various models of driver behavior one regularly observes, e.g. tailgating, weaving, stomping on the gas followed by hard breaking. Then insert a few wave cancelers and note its effect on smoothness and rate of traffic flow.

    1. Great Idea!

      I know from work done by other academic teams the computer controlled vehicle with highly optimized driving algorithms are able to get about %30 better fuel economy than the average human driver.

      It would be really cool to study expert hipermilers, and see what they special tricks are. Then through law changes, make everyone go back and take a class about fuel efficient driving when they have to renew their license.

      Computer models are interesting, but only real world data will tell the truth.

      Self driving cars are getting closer and closer to becoming a commercial reality: along with that technology, we can also push to get computer assistants that give real time feedback and suggestions: including routes that are topographically optimized for fuel economy, where the computer tells gives you hints that would otherwise be hard to know without the real time data analysis. A computer system with a very accurate map, optical sensor, machine vision and network access: will be able to do this effectively.

      Even when vehicle do not burn gas, conserving hydrogen and electricity will still make fiscal sense.