Hypermiling the Highlander Hybrid

[Sovereign]

Originally Posted by LUVMY02CREW

Thats some nice numbers!!! Good job.

I am thoroughly impressed by those mpg's because we bought our 2006 Hybrid Highlander, 2wd V6, 4 months ago to replace our Suburban.

Our Highlander had about 111K on the odometer. I just looked at the "consumption" screen and it showed we have put 3760 miles on it and have gotten 22.8mpg. That pales in comparison to yours

But in our Highlander's defense....it is a basically a taxi. My wife is the main driver and her work commutes to her school are about 6 miles round trip, lots of taking kiddos to and from places in town also. Not awesome mpg's but we can live with it.



My questions to you are...
1 - Do you reset the "consumption" screen for each trip?
2 - Do you know if the system keeps track of overall lifetime mpg somewhere?

Thanks

Congrats on your upgrade :P

1. No. I reset per fill-up (I never actually empty the tank).
2. Not in anything that shows up without any additional modifications (I'm not sure if, say, a ScanGauge or something which interfaces with the car's computer could show more than what Toyota already tells us such as a hidden lifetime MPG if it exists).

Careful use of a thermistor hack might enable you to get better mileage. However, note that you DO need to know what your engine's temperature is to avoid engine damage. See the posts about "let the engine warm to 100F then start faking" and the like.

Not to be a downer, but you're probably getting closer to 22MPG than 23 if your computer's like mine (0.5MPG too optimistic).

To add, I'm only getting this kind of mileage because it's warm. As soon as it gets cold, I fully expect my MPG to plummet.

Your wife probably doesn't know much about pulse-and-glide which is how I get my mileage so high. Essentially, the goal is to travel as much distance as possible with the engine off. In a hybrid, this is both normal and safe because the ICE deactivates on its own. The key is to keep it off as much as possible.

I've thought up the term "driving without battery" to describe how hybrids should be driven. Sure, you have this electrical system, but to get the best MPG you actually don't want to use it very much. If the traction battery keeps draining, at some point the ICE will kick in to charge it, dropping your MPGs through the floor. Use the big battery for accessory power, nothing more.

Back to P&G: it's a real pain in the HiHy. Your foot has to be in exactly the right spot to hit "ICE off, electric acceleration off, regenerative coasting disabled." If you do it enough, you'll eventually start building muscle memory and it will become far less of a stress on your right leg.

My trick is to drive with the battery-wheel mode showing in the odometer. Sure, the MPG might seem cooler, but that doesn't tell you HOW you're getting that many miles per gallon (using coast, using electric assist). You say you have a "consumption" screen--I think those only come in the version with navigation etc. Assuming that's the case, here are my highway methods.

Pulse and glide does not work on the highway for the HiHy! DO NOT try it--you'll only marginally beat the cruise (25MPG). If anyone has actually been able to get this tank to coast for any significant length of time, please share. Otherwise...

At highway speeds (40MPH-65MPH) you want to actually make use of the electric system. Keep the battery-wheel mode on the odometer, and switch to Consumption on the big screen. This gives you an instantaneous MPG readout AND a "where's my power coming from" readout. You'll have to learn at what throttle point the electric motors cut out at higher speeds. Once you do, find the spot where momentum is mostly maintained with as little throttle as possible. That will give an MPG readout of anywhere from 40-60 if done right since it's a mix of ICE power and electric assist. So long as the "high speed" doesn't covert to "parking lot" draining the traction battery won't actually hurt your mileage. The traction battery recharges very quickly at these speeds (coasting, braking, ICE charging). This enables me to maintain 30+ on the highway as well, without dropping below safe velocities.

PS: With only two wheels sucking power from the traction battery, you should be able to beat my numbers once you figure this stuff out. I fully expect to hear about 35MPG and feel bad

[Sovereign]

Fair to say 35MPG is out of reach without mods/even more extreme hypermiling. Boo.

On the other hand, even with the A/C on, I can consistently hit 30MPG pump and computer. I think that's good enough--it's more than double what a comparable gas-only Highlander would be getting on the commute I take.

[SentraSE-R]

Have you searched Prius pulse and glide on Youtube and tried that technique with your THH? It relies on gliding below the speed the gas engine runs mandatorially, and Prius users use it to get 100+ mpg.

[Sovereign]

I have indeed. That only works when there's enough room to glide without battery crawl kicking in. This happens more often than I would like and once the battery drains, MPG goes bye-bye as the ICE insists on running (getting 5MPG in the process). In choked Boston traffic, it is often the case that the "glides" are too short to really help with fuel economy. Combine that with the HiHy's greater mass, higher drag coefficient and increased rolling resistance and the trick doesn't work nearly as well. It "works" in that using it to the best of my ability allows me to regularly turn in 30MPG (or fractionally under it). But cracking 35MPG seems to be out of the question.

Hilly terrain combined with poorly-maintained roads don't help either.

[Sovereign]

And I find out the commute route matters more as well. I've dragged a tank (~175 miles) up to 32.2 on the computer (which was accurate down to the tenth of a mile per gallon the last two tanks). Going around Boston as opposed to under it gets me there and back faster AND improves my fuel economy. The traffic never really fully stops--there's enough yo-yo between fast and slow that I can actually USE the battery (drained all the way down to 2 bars) in slow traffic, but regenerate through methods that don't involve pure idling (coasting, braking).

[Sovereign]

A NEW RECORD: 33.8MPG!

The computer was TOO LOW. Yes, I accounted for top-ups, and everything. It's true: This car can probably do 35 with more aggressive hypermiling and some aero mods.

[LUVMY02CREW]

Last night we took the Highlander to the next town over to eat out with bro in law and his daughter- 4 adults and one child.

I had to fill up the gas tank, so that was a little extra weight also. I reset the consumption screen just to see what I could pull off mpg wise for the trip.

30.3mpg 34 miles total round trip distance

I'm pretty happy with that. I can't think of any other trips that I have gotten that high mpg.

[SwamiSalami]

How fast were you driving?

[LUVMY02CREW]

Originally Posted by dieselbeetle

How fast were you driving?

The posted speed limits...30, 40, 55...both in town and on a 2 lane rural highway with several hills.

I tried to use the cruise, but too much other traffic that would slow down then speed up. I just maintained a 6-8 second space between me and the next driver so I could coast and absorb his speed differential when needed.

[Sovereign]

And now I tumble back to mere-mortal status. I fully expect 25MPG or less due to massively unfavorable local terrain (lots of hills), short trips (3 mile roundtrip or less) and colder weather (engine runs more).

On the other hand, I'm only driving ~10 miles/wk now since my job is right in the heart of Boston (public transit, FTW).

Even 20MPG is about 30 week's worth of fuel at that usage rate.