Monday, May 30, 2011

Killer mileage

41.1 miles, mostly pulse and glide, Scangauge very conservative. MFD would read around 86 for this result. I got redirected twice cause of Memorial Day celebrations, hard to believe it would have been higher without the slowing and accelerating for low-speed detours.

In case you're wondering, the Prius display is showing the average over the last three tanks, doesn't reflect the craziness that is the current tank.

One of the main things I did, just like the previous day to Boston, was to have relatively long, gentle accelerations that would go with the terrain. This would allow me to keep the state of charge as high as possible (I basically had 6 blue bars all the time, would try not to dip below 58% SOC). This might mean the engine is on longer, but if you can go up a gentle uphill at 30 mph getting 40-50 mpg and simultaneously charging the battery, I don't see how it can be beat from a daily driving, practical standpoint.

Interesting thing about that - now that I'm "trained" with a Scangauge, I frankly don't need it once I'm in stage 4. Everything I did today could be done without it. I will keep it, however, to know when the coolant reaches that magic 157°F :-)


Boston and back. It was a long but rewarding trip. I was coming from work, even farther from the city than home, so I drove about 77 miles, almost all on back roads. I took the highway for a small portion where I knew the speeds were quite slow around Providence, so I could go 50 mph safely in the right lane.

The start, averaged about 75 before getting on the highway:

I knew I'd lose a little, but 9 miles at 50 mph versus 25 mph would be a nice little chunk of saved time. I only got down to 71.8 mpg or so after that stretch, and quickly bounced back up near 75. But then the streetlights came - lots of red ones. See the couple bars on the left? There were more like them:

Somehow bounced back to 74 for the trip - helps that the last bit of Washington Street/South Street is downhill, I could make sure the SOC was decent enough (actually was in 60s at end, even with all the pulsing and gliding!) for the final crawl up Huntington.

Wentworth had a good view of the city all day.

Hanging out.

Awesome day of hanging out and eating Ethiopian food with my sister and some friends. Wish I had more than a cell phone cam for stuff like this, but check out the sailboat in the Christian Science Center reflecting pool.

Thursday, May 26, 2011

Hybrid as a sound investment

So I've had Wentworth for a solid six months, and financially, I could not be happier. The car is actually worth more by several thousand dollars than when I purchased it thanks to rising gas prices, even though I've driven it 7,000 miles. Everything's running smoothly, no costs in terms of repairs, and about $20 spent on changing the oil myself. Now here's the really cool part:

I've saved $857 in the last six months on gas alone. Check out the spreadsheet (edit: note that as of publishing I had saved $857. This spreadsheet will automatically update to provide the most recent figures).

There's a notable increase in gas savings the higher the cost of a gallon of gas, check it out in the last three months of the spreadsheet when prices skyrocketed.

And this is where I'd like to address a classic hybrid concern...

"But Mike, your battery is old technology, and will last a couple years at most. I hear it costs $5000 to replace, so your savings mean nothing."

This is adorable and all, the problem is that you might've heard that on TV somewhere by a talking head, and it is wholly untrue. Naturally, the fear of high costs and pricey repairs stick well with the public, but in reality, if it even does ever fail, the Prius hybrid battery typically lasts north of 150,000 miles. Recent failures I've read about on PriusChat have been closer to 200k miles, and a Vancouver taxi reported replacing theirs at 300,000 miles. So driving 15,000 miles a year, I'm really not concerned about a possible repair seven or eight years from now.

Even if there is early failure, reported prices at PriusChat for a refurbished battery shipped and installed come in under $2000. With literally millions of Prii on the road today as hybrids settle more into the mainstream, this price has nowhere to go but down. If this happens at 200k miles, you're paying a penny a mile. Hardly a concern, especially given I'll save that much in gas money after about 14 months of ownership.

Stop worrying about the battery, everyone - remember, your single biggest cost when owning a vehicle is gas, pure and simple. If you keep a vehicle for a reasonable life, it's quite possible you'll pay more in gas than what you paid for the car over that period of time.

Wednesday, May 25, 2011

Fill-up, Tuesday, May 25, 2011

Last week's partial fill-up:

493.6 miles
7.000 gallons

Plus this weeks fill-up:

511.7 miles
8.095 gallons

Equal the total:

1,005.3 miles
15.095 gallons

66.60 mpg
3.53 L/100km

Wentworth's complete fueling history

I can't believe these numbers. I want to say it's just the bladder, but if it is, my gas tank is getting smaller by a gallon a week. I did very conservatively adjust the Scangauge so that the numbers I see are likely just below the real mileage, but this seems like too much.

Then again, I did just implement some new pulsing and gliding the last week or so, and I've been getting mileage 5-10% better than usual as a result.

I also have been filling up at a BP pump, the gas that comes with BP's Invigorate additive. Supposedly more energy content to the fuel.

Maybe it's possible. Maybe it's not. In any case, I do hope the numbers are accurate, since I'm going for a record this coming tank (already at 65 mpg after a day of driving, including a short trip), and would love a precise record of it if all goes well.

Thursday, May 19, 2011

There's no right way to drive the thing - trip record to work

68.3 real mpg at the least from the Scangauge (this would read about 72.7 mpg on my Prius' display) over about 27 miles.

I am insanely ecstatic at this result. This route, even with warm temperatures in the past few months, always presented me with mileage challenges I couldn't quite meet. It would be common to see 60 mpg on the display, if I even got that high. High 50s were commonplace and a struggle. Hills galore, and most of it over the threshold for a Prius glide - the engine runs most of the time on this route.

The "discovery", or rather what others have known for a long time but which can only be found out through personal experimentation, is that there's no "correct" way to do it all. There's no one highway technique, and there's no one RPM or kilowatt setting at which you accelerate. I used Super Highway Mode and Warp Stealth, hard accelerations and light accelerations, no EV and some EV, all depending where I felt it was needed.

In some cases I accelerated much more lightly during pulse and glide. I've always *guessed* (though can't prove - anyone??) that turning the engine on and jumping directly to a good burn at 1600-1800 RPM can waste some energy. You know, when you hit the gas and you see instant numbers in the teens, then twenties, maybe if you're lucky 30 mpg by the end? At the beginning you just hear the engine rev on and get no torque - just seems like gas blasted into nowhere. So today I would turn it on gently, and aim for, let's say, 30 mpg (light engine, in other words) for the length of two telephone poles, and then try to glide for at least 6 more, for segment mileage of 120 mpg. The result was that my first 20 minutes looked like this one from the other day, even though today I was driving in rush hour, and the picture you just saw was from empty roads on a Sunday morning.

This also counteracts the nasty habit of hard accelerations in pulse and glide to slowly drain the battery (longer glide time = more battery use), until your accelerations are wasted giving 15 or even 20 amps to the battery. Higher state of charge, better mileage - what's next, free apple pie for Prius owners? :-)
EDIT from the next day:

Another awesome run on a totally different trip using same ideas. I've never done anything like this. 75.8 mpg over 20 miles, which would have read over 80 on the display!

Tuesday, May 17, 2011

Fill-up, Tuesday, May 17, 2011

493.6 miles
7.000 gallons *partial fill-up*

Wentworth's complete fueling history

The gas station was closing. I don't think it was the fuel bladder for once, I think the guy inside cut me off at exactly seven gallons - I had under one gallon to go, and also several minutes until they were supposed to close. Now it will be another two weeks before I find out my actual mileage. It's nice getting good mpgs, but I never need to get to a gas station.

Trip A showed 493.2 miles with two of the ten pips left (plus the 0.4 miles before I remembered to reset the trip odometer from the last fill-up, for 493.6 total miles), but I went for the cheap gas day. Plus I have to drive a cat to Boston tomorrow and needed to be sure I could last 130 miles or so. Long story :-)

MFD shows 66.5 mpg over 493 miles for the tank, thus my estimates of about 62-63 mpg. Earlier in the day it had been up to 66.9 mpg for the tank, but coldish temps (high 40s°F) and some downpours/wet roads quickly put a damper on it finishing up. Wentworth was surprisingly of little help - I had to stop the car once on the drive home and restart since Wentworth was doing his temperamental coolant thermos filling or some such nonsense - I was in stage 4 but could not get the engine to shut off for a glide. Thus the 75 mpg bar below for the first five minutes - the engine was already warmed up. The others, you can see, are rather mediocre in that weather. This is what that route can look like, even in cold weather.

And this is what it looked like today...


Saturday, May 14, 2011

Love thy parking lot

This is Wentworth parked today, right next to the exit of the parking lot.

Here is everyone else, close to the building, but nowhere near the exit.

I know, I know. This looks like some extreme nutbag case of getting your money's worth for every last drop of gas in the tank. In a small parking lot, well, yeah, that's true :-D. In a large lot like this, if you're interested in upping your mileage, the lesson is to always park facing out right near the exit. Always. No exceptions. Unless everyone starts doing this, in which case I'll have to retract my position so I can get the good parking spaces :-)

You're basically getting around 0 mpg as you wallow around in traffic right near the startup. Remember, miles per gallon can't simply be averaged together. If you get 5 mpg for the first minute as you idle, check your phone, turn on the radio, then slowly progress out, and then get 25 mpg for the next minute when you're driving at speed, you can't say you've gotten 15 mpg ([5 mpg+25 mpg]/2). Those low miles per gallon act very heavily as a weighted average. If math bores you, skip the next paragraph and just read the point below (secondarily, go buy a math book).

If you patter around at 12 mph for a minute, at, let's say, 5 mpg for 0.2 miles, you've used 0.04 gallons of gas. Let's say you manage to go another minute at 35 mph, getting 25 mpg in any number of large, shiny sedans with more horsepower than you can shake your fist at, thus covering 0.583 miles, using 0.023 gallons of gas. Altogether you've covered 0.783 miles on .063 gallons, for a whopping 12 mpg.

The lazy person rundown for scenario outlined above:

One minute at slow speeds getting out of a parking lot = 5 mpg.
One minute driving at 35 mph = 25 mpg.
Total "average" mpg = 12 mpg.

Or(!) park near the exit, get right up to that 25 mpg cruising speed. Sure, you used a little on startup, so let's knock you down to 20 mpg. You can see, though, that you'd be off on your trip already with 66% better mileage (20 mpg versus 12 mpg) when compared to the standard close parker. Gas prices are, incidentally, interested in these sorts of percentages, and will reward you for thinking about them ahead of time.

And that's why you always park at the exit of a parking lot.

P.S. Love this sort of stair stepper action! Bar on far left was accelerating up to highway speeds, yet still above 50 mpg over those five minutes. Next from left is highway, as is the next 75 mpg bar. After that lower speeds for better hypermiling in traffic. Tank is looking good, 66.7 mpg display over 396 miles. Should be low 60s in reality.

Sunday, May 8, 2011

Special place in hell reserved for hills

Four guesses where the hill is located on this chart.

Saturday, May 7, 2011

Wednesday, May 4, 2011

Fill-up, Tuesday, May 3, 2011

478.0 miles
7.687 gallons

62.18 mpg
3.78 L/100km

Wentworth's complete fueling history

A quite disappointing tank by a couple mpg, was thinking it would easily be 63 or 64 (MFD read 66.2 MPG for 478 miles). Had to re-calibrate the Scangauge down a bit more, probably the bladder playing tricks again.

Somedays you just want to move somewhere where it's flat. Yes, Rhode Island has a surprising number of hills in certain spots. In most spots it's relatively flat, but how do you think we get anywhere? We take bridges over water. Steep, steep, bridges.

I'd like to illustrate a little terrain lesson. There are hundreds (thousands?) of people who ask at PriusChat: why do I only get 45 mpg?


Besides the 10,000 variables (that's an approximate figure) that could play into it, terrain is enormous. Three days a week I get 25 mpg over the first 2 miles of my commute going up a big hill while the car's not yet warmed up. To do that, I use:

0.08 gallons of gas

I then can usually get over 100 mpg for the next 6.4 miles (I know these figures cause it's the distance to my Toyota dealer!). Once I calculated 136 miles per gallon on this segment when I got all green lights! It's wonderful for gliding after you get up that first hill. 6.4 miles divided by 136 mpg =

0.044 gallons of gas

Together, that's 8.4 miles on 0.124 gallons of gas, or 68 mpg or so.

Let's pretend I could get 50 mpg on the first two miles, say if that large hill weren't there and I could hypermile somehow. That would be 0.04 gallons of gas, plus the above second segment of 0.044 gallons of gas, for a total of 8.4 miles travelled on 0.084 gallons. The numbers are purely coincidental, but you can see that's precisely 100 mpg. If I had flat terrain the first two miles, I would get 100 mpg to my dealer.

But I don't get 100 mpg. I'm a 60 mpg driver, and that's still a good thing. And maybe you're a 50 mpg driver, or a 40 mpg driver, which is also great (average economy of new vehicles sold in 2010 was 22.2 mpg). Sometimes terrain just decides our mileage for us, and we can't do a damn thing about it - except complain on a blog :-)

Some positive notes:

This tank did see my first prolonged highway run over 60 mpg, and I had a whole bunch of nice trips above 70 mpg.

It looks like I'll likely stay in the low 60 mpgs for some time given my current commutes. Next year will be interesting, I'll be living elsewhere and will have a different commute altogether. Time will tell if the new terrain will be kind or not...

Sunday, May 1, 2011

Highway Hijinks

62.5 mpg over 50.5 miles

This car does not cease to amaze.

After driving with Hobbit that one day on the highway, I had a much better idea of what was going with his sweet spot posts. My way home that day was mildly successful, netting me probably around 56 real mpg with the hilly ride home.

Since then, I've been able to work the 15 kW routine into regular driving, including pulsing and gliding during my commute, for really wonderful figures, in spite of hills and stoplights run amok.

That being said, really quality (60+ mpg) figures have still eluded me on the few pure highway trips I've taken. Well, this morning I had the perfect opportunity to try again. I had gone up to a friend's last night (73.8 mpg over 37 miles, thank you Hobbit for 15 kW pulsing and gliding!), and then had to drive straight to work today, a drive of about 50 miles. Rather than go for a couple hours on the backroads, I decided to man up and just take the highway.

Before we start, please keep in mind that all figures noted in this post are from a calibrated Scangauge, and are very close to the real deal.

Starting out in temps of 48°F in a car that had sat overnight, I got to the highway after about 1.5 miles of 30 mpg warmup driving. I got right up to speed of around 65 mph, then tried the 15-18 kW acceleration trick combined with warp stealth downhill. For a good deal of time. I had really wanted to stick with it all trip, but the downhills didn't seem long enough to make up for uphill burns. Even when I was accelerating at the upper end of the high-torque sweet spot, I couldn't get to a high enough speed to justify using warp stealth by the top of each hill. I'd spend most of the time accelerating.

After 16 miles of this, my mileage was creeping up, it was in the high forties, then low fifties somewhere, but the whole thing was so much effort, especially with the terrain, and the five minute mileage bars were nothing special - all over 50 mpg easily, but not much higher than 60 if at all. I'd have to drive all day like this to get the average fuel economy up into the 60s.

Now, I should mention that I don't consider this a critique of Hobbit's style (the guy has got some!), but rather of my ability to control and use it properly. As the speed limit slowed to 55 anyway, I thought I would try Super Highway Mode.

The results were immediate. Next bar near 75 mpg, next somewhere in the 60s, and so on. Another 19 miles into the trip (about 35 miles in of the 50 total miles), the mileage figures were in the upper 50s, flirting with the 60 mpg mark.

I kept on, and finally 60 was broken, and it kept trekking higher - until the 2500 RPM hills came. The last 2.6 miles were hypermiling land, but even before I got to that, the mileage was still handily over 60 mpg.

So, the next logical question is how...

I travelled largely between 50 and 55 mph, set 50 as a floor for part, then 55 for another segment to see if it would still work (it did). At a given speed, I held 14 IGN on Scangauge, or occasionally 15 IGN if I really needed it (IGN on Scangauge shows ignition timing, by the way). If my speed floor was hit, I would accelerate back up a couple miles per hour faster (or just to the top of the hill if the terrain made that choice logical) at the most efficient accelerating output possible (so 15 to 18 kW) and then flipped right back to IGN 14.

That was it.

While at IGN 14, the mileage tends to be between 60 and 85 mpg. I had always thought you would lose excessive speed this way, but it wasn't the case. Using IGN 14 you slowly accelerate on the slightest downhill or even a flat (I got up to 60 mph a couple times without trying). At IGN 15, I accelerated more quickly than I thought on flats, and if you get to your speed floor on an uphill, it would usually only take a couple seconds of an efficient burn to get sufficiently back up to speed to use IGN 14 or 15 again. Unlike the warp stealth technique, the harder burns are not long at all, but quite short to bump you up a couple mph at the most. The result was that almost all time was spent between 60 and 80 mpg.

I rarely used warp stealth this trip, though I did some, especially in the second to last five minute mileage bar you saw in the second pic above (yes, that 100 mpg bar was at 50 mph, I just knew the terrain well at that point in the trip and could exploit it) and on longer downhills where I wouldn't lose much if any momentum. It was probably the most I've ever used the engine in a trip - I kept gas burning almost the entire time.

Some thoughts:

-I realize not everyone has a wide highway with Sunday morning traffic where they can go 50-55 mph. That being said, 55 mph is the speed limit in many places, and this would conceivably work at 60 mph, though with reduced efficiency, which would be perfectly acceptable in my area, especially in the right lane.

-If I take out my warmup of 1.5 miles at about 30 mpg (0.05 gallons) and the last 2.6 miles of hypermiling off the highway at 75 mpg (0.03466 gallons) from the 50.5 mile trip that used 0.808 gallons of fuel, I get a 46.4 mile trip using .7233 gallons of fuel, or slightly above 64 mpg for average highway cruising mpg throughout the trip - and that was with hills. Anyone driving on flat ground could definitely coax their Prius into better results.

-This was an astoundingly refreshing, stress-free way to drive. I absolutely love hypermiling, but it typically involves a corresponding hyperawareness of everything around you, both within the engine and without the car. Personally I'm constantly looking ahead and in every mirror to make sure I don't block a stream of traffic with a glide. It's always constant motion and thought. With highway driving at IGN 14, all you do is keep it at that one metric. That's it. If you want to go faster you go into familiar 15 kW territory for a several seconds, then back to normal. The speed fluctuations are very minimal, so if you're already in the right lane, you don't have many people flying up on your tail. You're just driving. Easy. Even if I could get the hang of Hobbit's technique, I think I would choose this one for the simplicity and relaxation I got out of it. I absolutely loved it.

-If you go onto the highway for 6 miles a day, don't expect to have a 60 mpg average. My average started low during the trip and worked it's way up gradually like I mentioned. This technique would work wonderfully on long road trips.

I don't think I've left anything out, it really was that simple. I was absolutely ecstatic to have beaten 60 mpg on the highway. Think about this: with the adjusted highway estimate for the 2007 Prius being 45 mpg, a result of 62.5 mpg with SHM at 14 IGN is 40% better than the EPA! Please ask any questions if you have them, and let me know if you're able to achieve good results on longer highway trips.