Tuesday, February 22, 2011

Fill-up, Tuesday, February 22, 2011

410.2 miles
6.309 gallons

65.02 mpg
3.62 L/100km

Wentworth's complete fueling history

Driving is on sale, only $19.99 for 410 miles!

Wonderful results, though the next fillup will reveal whether the bladder was contracted (this is not a joke...). You see, on Generation II Prii like Wentworth (model years 2004-2009) there is a gas bladder which expands and contracts with the gas volume found inside the car. It does this so that it can keep the overall volume of the tank down to prevent fuel evaporation, since those vapors can leave the tank during refueling, thus wasting gas, your money, and of course slightly harming the environment. If the bladder does not fully expand during fuel up, then you will pump fewer gallons until it's "full", and the math will give you a higher mpg than reality. It all works out over multiple tanks, of course, so no worries, it's all about the overall average.

That being said, it's possible this was my actual mileage, with almost 10% of the tank being those 37 miles at 80.9 mpg displayed, and a couple trips up in the 70s, plus a whole bunch in the mid 60 mpgs. Arguments for the gas bladder not being fully expanded, though, would be the couple trips I tried on the highway (see below), where I got mid to high 50 mpgs.

Time will tell...now for some tank pictures. (EDIT: The fill-up after this one confirmed that the 65 mpg number was real!)

Wanted to experiment with highway driving. 55.5 mpg over 26 miles. Although not bad for any car in 23°F, I'll need more practice. Hobbit is able to find a surprisingly fast sweet spot and gets 70 mpgs on the highway. You can see on mine most of the time it hanging barely over 50 mpg, just at the end since it was late and there were no cars on the road I used some nice hypermiling for last 10 minutes of 100+ mpg. One other highway trip on this tank (this route but in reverse) showed 58.5 mpg.

Thing is, I'll still try to avoid highway driving. This ride below is the same departure point and final destination as above, but is 6 miles or so shorter with mpg shown at 69.7 mpg. You can guess which route I'll take regularly...

71.7 mpg over 27 miles. Same route as the 73.3 mpg from earlier in the week.

Friday, February 18, 2011

Hypermiling attempt #1, 80.9 mpg over 37 miles

Attempt numéro un:

80.9 over 37 miles, and within that trip, about 92.46 mpg over 32.5

The titillating details

So it was a lovely Friday morning, and although I had some things to do, I couldn't ignore the mid-40s to 50°F temps outside, the warmest I've had yet since owning the car - so I headed out for a some first hypermiling attempts.

There is a rare stretch of a mile in my town with a. no traffic lights, at least until the end of the mile, and b. two-lanes so that people could pass me. I wanted to try this out first.

I attempted to accelerate to speed (40 mph) at about 25 mpg average over .2 miles, and I was able to just about hit the numbers (probably .25 or .3 miles). I let up on the accelerator for the engine-off glide, and let the car go. There were some humps in the road a little too big to ignore, so I used minimal electric energy to keep the glide going. At the end of the mile (a little before...when I was crawling to a stop and there was a convenient road to turn into), I had about 89 mpg. I then turned the opposite direction, rinsed and repeated, and came out with 98 mpg for both of those miles combined.

The problem was, if I wanted to do this repeatedly to get 100 mpg over many miles, each time it would necessitate turning around 180° and starting from a dead stop, and obviously that's not ideal for mileage. I also felt I had to use too much EV (electric mode), which would wear down the battery too much after a couple passes. If I tried over and over, I would imagine on one of the attempts the gas engine simply wouldn't shut down, as it would want to recharge the battery pack.

So I tried something else...

I've been wanting to scout out some back roads in two nearby towns to see what I could do with hypermiling and no traffic. The particular towns in question have a wonderfully low population density, and not too much traffic to go with it. The one problem is that all roads are one-lane over there. I don't know the roads at all, topographically speaking, so it was a bit of challenge.

They worked out pretty nicely, but not great. There were lots of lightly rolling hills, and without knowing where they were, I would sometimes get lucky, but sometimes not, having to sustain the engine on for much longer than one would want trying to get 100 mpg.

At the end of the stretch of road there was an awkward turn around (by the end, since I'm in Rhode Island, I mean when I had to stop to avoid driving into the ocean) which lowered the average quite a bit, but I think I it should be possible in those towns in the future to have a go at 100 mpg for at least a half hour. I'll have to go at a time with no traffic, since around 10-11am when I was there, although mostly clear, I did have to either speed up when I didn't want to or slow with my hazard lights to let others pass.

Now, as I headed over there on the highway, pretty much all gradually uphill, I travelled about 2.3 miles at, I would guess, 30-35 mpg average from a 0-50 mph acceleration. I didn't reset the mileage display, so those numbers are figured into these 37 miles. On the way back, more down hill, I would guess a 50 mpg average on the highway portion. There's another couple sustained 20 mpg uphills I had to do on the way home which I won't even take out to keep the numbers conservative. So if we take out the gas consumed on the highway miles (.111 gallons) and subtracted those miles as well (4.5 or so), you get 32.5 miles travelled on .3515 gallons consumed, or 92.46 mpg. So conservatively, good to see Wentworth can get at least 90 mpg over about 32.5 miles!

Monday, February 14, 2011

"Oh, yeah!!" -Kool-Aid guy

NICE! Warm weather apparently does wonders. Displayed mileage of 73.3 mpg over 27-mile hilly route.

I even stopped on the way home at the Toyota dealer where I bought it to show them (it was at a red light anyway...) since I knew the numbers would be staggering at the end of the trip.

Sunday, February 13, 2011

Fill-up, Sunday, February 13, 2011

406.8 miles
6.920 gallons

58.79 mpg
4.00 L/100km

Wentworth's complete fueling history

So close!

I decided to go to the gas station a day or so early, since I was in the middle of an engine-off glide with some momentum that I didn't want to waste by slowing down to turn down the side street to go home, and the light was green with no traffic. After all, always best to combine short trips into the end of longer ones.

Just a little shy of the magic 60 mpg, which to be honest, surprised me a little given the single trip readings this tank. Yes, the display on the Prius overestimates slightly, but I had thought most of them were sufficiently above or at 60 to make it work. I imagine that the margin of error increases immensely the higher you go with your mileage. If you use .1 gallons of gas over 10 miles, you get 100 mpg. If you calculate wrong and say .11 gallons over 10 miles, you get 91 mpg. When it's a matter of many miles divided by very small, precise fractions of gallons, there's lots of room for error.

There was one day with wet roads that I remember really killed the mileage (I find wet roads are worse than cold), plus the 19°F trip, and a couple other cold trips where I could not get the ICE to shut down in a timely manner.

On the other hand, there were lots of other good ones which I'm pretty proud of!

In any case it was my best tank, and I'm happy with it given the terrain I have to drive in and the winter temperatures.

61.0 mpg this morning to work over 26 miles in 25°F.

Halfway through the trip home today. I just liked the stairstepping action on the screen!

Good ride home today, 66.1 mpg displayed over 27 miles.

Wednesday, February 9, 2011

Wentworth's working hard in the cold

After my post on Monday about short trips and killing kittens, I decided to calculate the potential hit for my own routes. I took mpg samples on my Tuesday and Wednesday obligatory short trips, and was pleasantly surprised. While it's certainly no fun to see each of these trips individually (one of 1.1 miles netted me 30.1 display, ouch!), the fact that I'm apparently able keep the average mileage during all of the week's short trips to about 46.2 displayed mpg (so likely about 44 mpg in real life) means that it won't drag me too far down from 60.

In fact, on a tank spanning two weeks, and thus two Tuesday/Wednesday combos of short trips, I would only have to get slightly above 62 mpg on all my other 433.8 miles to still get about 60 mpg, even with the 46.2 miles of 44 mpg (you can see I'm aiming to fill up about 8 gallons. 433.8 miles + 46.2 miles = 480 miles). On tanks like this week, where I have to drive more than usual, I may only hit Tuesday/Wednesday once on the tank, and I only need a little over 61 mpg on the other 456.9 miles (480 miles - 23.1 miles of Tuesday/Wednesday combo).

This seems like a tall order, and although I've had a couple of 58 or 60 mpgs displayed on the low end, you can see below I've had a good week overall, setting a couple route records, the latest of which was tonight back from work, at 67.7 mpg displayed in 28°F weather. Looking forward to the fillup results anticipated about Monday the 14th!

67.7 mpg over 12 miles

This one was tough, but got 61.9 mpg on the display over 18 miles. Wentworth wouldn't glide for about 12 minutes, it was so cold out - notice the 19°F in the upper right corner of the screen.

68.3 mpg over 27 hilly miles (I'm getting better with warp stealth!)

66.2 mpg over 20 miles

Monday, February 7, 2011

Everytime you take a short trip, a kitten dies. And you lose a lot of money.

So you love cruising around town. It's quality fun, no doubt, especially in the warmer weather, driving around, radio blasting Billy Joel (or Creed, or Lady Gaga, or Stravinsky - whatever floats your boat). Nothing like jumping around from store to store during the week, going to the gas station to get gas, heading to the grocery store several times a week to pick up a meal for the evening, or driving down the street to drop something off to a friend cause it's quick and easy.

The zooming around town for every little errand is part of the American culture that stemmed from years and years of gas costing less than water (sort of like wine to the French). The thing is, the prices are creeping up once again, slowly but surely, and these habits from the days of sub-dollar gas prices are costing us.

The general rule is this:

Do not take short trips in your car(!).

Cars get their worst possible mileage in the first five to ten minutes of driving. In the winter, this time is prolonged and the mileage becomes atrocious during the warmup phase. To stop for errands, wait until your car is fully warmed up, and then stop for whatever you need on the way home instead of just after leaving the house. Go for broke on those grocery trips, get what you need for a week. Driving your car three miles on a cold engine, especially in winter, will absolutely kill your mileage. Even in my Prius, I know from my house to the grocery store from a cold start gets me about 20 mpg. If you think you're safe with a 25 mpg average EPA rating car, you're probably getting 10-15 mpg during the first few minutes of cold weather (sitting at the stop light is 0 mpg, by the way!).

Let's do some actual calculations. Let's say you can get 30 mpg in your vehicle (very generous, the US average is below this). You expect to go 240 miles between fillups for a grand total of 8 gallons. My most recent gas price of $3.18/gallon would give us $25.44 for a fillup. Let's assume 1,200 miles a month for a total of five fillups in a given month, for a total of $127.20.

Now let's say that you drive a mere 30 out of those 240 miles on short-distance trips - to the grocery store, etc. At 15 mpg your mileage will instantly drop to 26.66 mpg for the entire tank of gas. You've lost over 11.1% of your mileage, and you're paying 12.5% more at the pump. That monthly gas bill jumps to $143.10.

Let's double that amount to 60 miles of short driving per 240 mile fillup. It sounds like a lot, but if you kept track for a week you would find a whole host of surprise short trips that add up. Bank, grocery store, post office, little shopping trip, gas station, dropping off something at someone's place (cause moving a couple thousand pounds of steel is reasonable to transport a piece of paper...go for your e-mail!) - it's easy to do.

With 60 of your 240 miles at 15 mpg, you now drop to 24 mpg, a drop of 20% from your original figure of 30 mpg, and you pay an whopping 25% more! For what other good or service would you pay 25% more than what you need to besides gas? The premium is enormous. You now pay $159 a month instead of the original $127. It's the equivalent of filling up your tank an entire extra time per month!

For the extra you spent, of course, that adds up into $381.60 over the course of the year. Seems better to save it than to spend it for no reason...

So what's the solution? Besides stopping only after the car is warmed up for errands and doing a lot of grocery shopping instead of a little, don't forget that bikes and your own feet get infinite miles per gallon. Walk up the street to the drugstore. Ride your bike to the post office. It's fun, more relaxing than driving, good for you, and costs you and the environment nothing.

Sunday, February 6, 2011

Solid trip, 65.1 mpg displayed

Solid 27-mile/43-km trip home from work this morning. I got 61.1 mpg or 3.85 L/100km going there in the morning, and 65.1 mpg or 3.61 L/100km on the way back. This is with pretty intense hypermiling attempts (that's right, driving slow can be intense), since the whole landscape is rife with hills, including two bridges that go waaay up (before the lovely backside down). I also had a couple inopportune stops (cut off by a bus just before a stoplight which I otherwise would've gotten through before it turned red - on an uphill), so it's nice to see the good numbers even with those. Those of you with flat commutes, be thankful!

Keep in mind the Prius display is generously inaccurate by a couple mpg, so the likely real life average for the roundtrip was 60 mpg (3.92 L/100km), which is my stretch goal for an entire tank.

Have a good weekend!

Saturday, February 5, 2011

Fill-up, Friday, February 4, 2011

376.7 miles
6.788 gallons

55.5 mpg
4.24 L/100km

Wentworth's complete fueling history

This tank was showing some excellent results with most rides in the low to mid 60s. The problem is that just a few bad rides can really knock it down. I had two in particular, and a third to a lesser degree, that were huge mileage droppers due to cold, but in particular moist weather, which seems to have a severe negative effect on the timely shutting down of the ICE (internal combustion engine), which is crucial in the Prius for higher mileage.

In any event, here are some snapshots from this past tank. It's important to note that the display screen can vary from about 2 mpg on average from reality, sometimes more. I always hand calculate at the end, so the 55.5 mpg you see at the top is from the gallons put in and the miles driven, not from the inaccurate display screen. I'm pretty confident that with a stretch of drier weather and temperatures higher than freezing that I'll have a nice crack at a 60mpg/3.92 L/100km tank (ok, 400 miles or so, I don't like to get close to empty :-D) sometime soon, hilly driving be damned!

Thursday, February 3, 2011

ice + ICE = Math class

Wednesday ended up being another moist, icy, wintry day that necessitated almost constant defroster use, and I knew the ICE (internal combustion engine) would stay on in my first trip of the day, bringing down the mileage. I also have a couple unavoidable short trips for clients, knocking down the mid-50s mpg for a one-way of my main trip to 44.8 mpg or 5.25 L/100km after 15.9 miles/25.6 km.

I knew on the way home, being a night drive on pure ice again, that it would be great to try some hypermiling with few cars on the road.

After I got home, with the return trip tacked on I was back up to 51.6 mpg/4.56 L/100km. This seems disappointing (only 44.8 up to 51.6?!?), but, of course, the drive straight home without detours to clients is shorter at 12.4 miles/20.0 km, and you can't average mpg just like that.

Which brings us to today's math lesson :-)

Here's a convenient formula for calculating mpg for the last segment of driving you've done, like for calculating the way home of a roundtrip drive. Most people need a ScanGauge, but if your car has instaneous mpg like the Prius, try it out. Of course, you can figure it out on your own, but sometimes it's more fun to be lazy and just use whatever you find on the internet!

It supposes a certain amount of information, like that you wrote down the distance traveled and displayed mpg after the first part of your trip. These are represented by distance1 (in miles) and mpg1 in the formula.

You also need total distance traveled in miles and total trip mpg, respresented by distancetotal and mpgtotal in the formula.

Just calculate the second segment of distance, represented by distance2, by subtracting your first leg from the total distance.

Plug it all in...

And I got 64 mpg or 3.68 L/100km on the way home yesterday in freezing temps!

Wednesday, February 2, 2011

When it rains, it pou...no, it ices over

Yesterday saw a pretty nasty combination of precipitation, clearly designed by Mother Nature for no other reason than sticking it to low gas consumption.

There was snow in the morning, which I dutifully cleared out of the driveway and off my car. But by the time I had to actually drive anywhere in the afternoon, a couple hours of light rain and sleet had (in)conveniently and thickly layered a sheet of ice over everything in sight, poor Wentworth included.

Since I was on the road to a decent two week tank of potentially 60 mpg/3.92 L/100km, I wanted to keep the streak by scraping the ice manually without running the engine. No problem, I do it all the time...


The first scrape lifted a fine spray of ice/snow/non-nomerable wintery substance off the window, but there was clearly a solid coat still below that. More scraping seemed equally futile. I eventually found a crack or two to work into, but even then it was the biggest sheet of ice I'd ever scraped on a car.

An hour and a couple cups of warm water to soften the ice later, I was off, wet, cold, and knowing full well that my Prius' ICE (internal combustion engine, not to be confused with the other stuff) does not turn off as often when there's moisture on the roads. Furthermore, the sleet kept freezing on the windshield, so any crazy defroster antics I might normally play to get the best mileage were out the window, and safety was the name of the game. So defroster and ICE running, I drove "like a normal person" through the 20 mph/32 km/h average speed limits and countless stoplights that get me to work.

I arrived with a mere 45 mpg/5.23 L/100km on the display.

This was actually not disappointing, but a couple things else:

1. Good! It's hard to remember when you can get in the 50 mpgs/4.7 L/100km without trying, and 60s/3.92 when you try, that 45/5.23 is excellent mileage for almost any other vehicle out there, especially in freezing temperatures.

2. Informative. The extent to which driving habits can affect your mileage (and thus your finances!) was not evident to me until a few months ago when I first tried the Prius. I've squeezed out 65 mpg/3.62 L/100km on this same route before, and getting 45 mpg/5.23 L/100km this time shows me how adjusting my habits, but getting there in the same amount of time yields a 44% improvement in mileage.

One other thing - on the way home, not wanting to spend an hour in the mist/rain/sleet/whatever again, I put on the defroster and started scraping. The car was on for maybe 10 minutes or so, and when I got back in the mileage for the 12 mile/19km trip was down to 36 mpg/6.52 L/100km (from 45/5.23 before)!

You can see, if the ice isn't terribly thick, and running your car in the morning before you actually drive just saves you a couple minutes in the name of convenience, or "warms it up", kick the habit. Modern cars really don't need that to save the engine, and you're getting precisely 0 miles per gallon that entire time (it sounds even worse by saying infinite L/100km!).

I also drove "normally" on the way home, since the roads were pure ice at 23°F/-5°C outside temp, save for a little gliding when I could, for a more respectable but still weather-reduced 55 mpg/5.14 L/100km.