Article,EPA,Hypermiling

It’s a Game of Averages

11 Sep , 2016  

– Tony Schaefer

Many times, when discussing hypermiling techniques, someone will ask about how to approach a hill, or what to do in rush-hour traffic, or when driving in bad weather can’t be avoided. The only sane answer is, “get over it.” Let’s face it: if you are going to scrutinize every single mile or every single minute, you will go insane. That is why hypermilers talk in terms of tank averages and lifetime averages.

Tank Average

This should be your smallest unit of measurement except for the rare exception. It is only over the course of an entire tank that you can take multiple factors into consideration: morning versus evening commutes, good weather versus storms, etc.

If you wish to maintain daily logs – and for various reasons, I have suggested just that – bundle them into the tank average and then throw them away. Daily logs are for analysis and review only. For example, another article suggests keeping daily logs for the sake of identifying the best daily commute. Once these logs have served their purpose, dispose of them.

The easiest way to calculate the tank average is to divide the miles driven by the amount of gasoline used to refill the tank. However, here are some factors to consider:

  • Some cars use bladders inside the gas tank to help contain vapors. Depending on the ambient temperature, the bladders might be more or less flexible in warmer and colder conditions, respectively.   For example, the second generation Prius used a gas bladder. In the summer, almost 10 gallons of gasoline could be pumped whereas in the winter as little as 8 gallons was the maximum. The Prius fuel bladder was removed starting in 2010. This is an issue because it adds a variable when attempting to accurately calculate the amount of gasoline used during the tank.
  • There is always the debate whether the on-board calculations provided by the car are accurate enough to be used. Some people choose to perform their own calculation rather than trusting the car. Anecdotally, some people have used both and shown that over a period of time, the over/under evens out and both methods arrive at the same Lifetime Average. However, for the individual tanks, which method you use is up to you.

Lifetime Average

Of course, the granddaddy of all averages is the overall Lifetime Average. This reflects your entire driving experience with the car. Lifetime averages do not need to start when the car is brand new; it is the one-number record of you and the car working together as a team, regardless of how old the car was when you two first met.

As you can imagine, calculating the lifetime average requires that you know exactly how many miles you have driven and exactly how much gasoline you have consumed. Not just for one tank or one month or even just one year. In order to calculate an accurate lifetime average, you must have been recording accurate fuel data for the entire time you have been driving the car. Trust me: this can get tedious but it is what must be done to achieve the goal.

12-Month Rolling Average

As you drive your car year-over-year, you might become curious whether you are becoming a better hypermiler. Actually, it’s great to constantly want that feedback to spur improvement. The problem is that the Tank Averages can’t be compared one-to-one and after a while the Lifetime Average barely budges.

This is where the 12-Month Rolling Average comes in. Whereas the Lifetime Average will forever be influenced by those first few crappy tanks, the Rolling Average will eventually let them go to reflect how you’re doing now. Though you can’t throw them out completely because they are part of your historical record, they are no longer an accurate representation of your current driving ability.

Calculating the 12-Month Rolling Average requires that you go back one year (sounds pretty obvious, doesn’t it?). Where it can get complicated is that the number of tanks will vary. For example, if you average a refill every other week, you cannot simply take the last 26 tanks and assume that’s a year. There will be those long-distance road trips in which you consumed a full tank in only two days. So just be careful and make sure to do the math based on the dates: sometimes 28 tanks, sometimes 32.

Conclusion

If you only keep two averages, they should be the Tank Average and the Lifetime Average. These give you a real-time feel for your hypermiling abilities and an overall view of your entire driving experience. Adding the 12-Month Rolling Average provides an updated perspective, showing how you’ve done over the past year.

 

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Article,EPA,Hypermiling

Planning Trips

5 Sep , 2016  

– Tony Schaefer

In another post, we discussed how to best handle your day-to-day commute by finding a mileage-friendly route, memorizing it, and documenting how well you do. This article will address how to handle those unexpected and irregular trips. For example, running errands on the weekends.

Combine Trips

This should be obvious but I’m just throwing it out there.

Quite possibly, the silliest thing you could do is to make a bunch of little errand runs throughout the day. As long as you’re out running errands, hit all your stops in one go. Seriously, there’s not much more to write about this except to make note that the order in which you combine all your trips is important. So with that…

Go to the Farthest Destination First

It seems like the easiest and best thing: go to the closest destination and progress out until you’re at the farthest destination and then head home. However, in terms of mileage, this is the worst possible way to approach the situation. Here is the underlying reason: cars get better mileage once they are warmed up. If you string together a bunch of short drives, the engine will never have an adequate chance to properly warm up. It will always be running in an inefficient warm-up mode.

By starting with the farthest destination, the engine will have that initial chance to get completely up to temperature and start running efficiently. Then, when you head to the second stop, the engine is starting from a warm condition and is more likely to return to optimal temperature before stopping again. The same goes for all subsequent stops. The point here is that you want to give your car at least one long drive to reach optimal temperature.

As with all things, there are exceptions. The above advice works great for non-perishable errands (crafts store, hardware store, library, etc.) However, if the farthest destination is the grocery store with frozen food, you might want to plan the route so you get there last before heading home. If the farthest destination is a restaurant of the theater, you’re going to want to end there.

Consider Taking a Roundabout Route

If you are out running errands, then you’re probably pretty familiar with the area within about 5 miles of your house. With this in mind, you should have a pretty good understanding of traffic fluctuations in relation to a place, time, and day of the week.

When provided the opportunity, take a more roundabout route if it means dodging traffic situations and stoplights. Keeping clear of traffic situations could mean better constant-speed driving as will dodging the stoplights and stop signs.

Did you know that UPS drivers are routed in such a way as to minimize their number of left turns?

UPS engineers found that left-hand turns were a major drag on efficiency. Turning against traffic resulted in long waits in left-hand turn lanes that wasted time and fuel, and it also led to a disproportionate number of accidents. From 2004 to 2012, the right turn rule combined with other improvements saved around 10 million gallons of gas and reduced emissions by the equivalent of taking 5,300 cars of the road for a year.

Think about that. Not only does turning right mean that you spend less time waiting for traffic to clear, it means that you do not cross lanes of traffic as much. Turning right is much safer than turning left.

One consideration that might be a bit of a stretch is that the less-than-direct route might have better roads. In other words, find a path that avoids crappy roads. No doubt you have noticed that your car rolls better and gets better overall mileage on freshly paved, smooth roads. If provided the opportunity, define your route based on traveling on the smoothest roads. Besides, driving on rough roads just plain stinks.

All these things, when put together, might provide a more fuel-efficient route than heading directly to the destinations without any forethought.

Run your Errands when it’s Warm Outside

This concept works in combination with driving to the farthest destination first. Driving when it’s warmer outside will help your engine warm because the air rushing past the engine will be warmer. In some geologies, the morning-to-afternoon temperature swing can be several degrees. You need a sweater in the morning but have stripped down to a T-shirt by mid-afternoon.

If you like to get up and out as early as possible, that’s fine; just as long as you know that you might be taking a hit to your mileage. If you can wait a few hours, when the outside temperature is higher, you will be rewarded with better mileage. In the meantime, find other things you can do perhaps around the house or whatever.

Give Yourself Plenty of Time

This is a tried-and-true mainstay of hypermiling. When we feel rushed, we tend to make bad decisions, press a little harder on the pedal, and generally compromise the hard work we’ve done so far.

So here’s what you do: as long as you’re waiting for the temperature to go up, plan your trip so that you hit the farthest destination first. Once you’re done with that, figure out how long your entire trip will take and leave on time. So you see, a bunch of these concepts fit hand-in-hand.

Conclusion

Sometimes we have to make that one-off trip to the grocery store or hardware store or whatever. But when a series of errands require that you top at multiple destinations, taking a little time to plan it all out could reward you with improved overall mileage.

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Article,EPA,Features,Hypermiling

Document, Document, Document

25 Jul , 2016  

– Tony Schaefer

“That which is documented is measured.
That which is measured is improved.”

There are several attributes as to who originated that quote, whether it was ever actually spoken, or whether it’s a mash-up of multiple quotes. As important as is the origin, the impact it can have is equally so. Basically, it’s this: if you want to improve something, start documenting. However, documentation does not, in and of itself, result in improvement. That’s where the middle step comes in: the documentation must be measured and comparisons must be made. After all, sheets of detailed documentation would be meaningless if they were tucked into a binder and never reviewed.

What Do We Document?

The following is going to be a list of as many possible things as I can imagine. In no way am I saying that you must document it all or even that every item is important to you. It’s up to you, your priorities, and your gumption to decide how far you wish to take the whole thing.

Route Timing (with waypoints)

Sometimes, the speed of the drive is more important than the mileage. Or perhaps you’re interested in finding out exactly how much longer it takes to drive one route compared to another. Consider using a small notebook and a pencil to make note of when you pass certain intersections or other static waypoints.

Create a table on the sheet. Down the left, list all the waypoints. Along the top, list Mon, Tue, Wed, etc. or perhaps Day1, Day2, Day3. Whatever. The waypoints should be far enough to allow a measureable amount of time but close enough that the measurements aren’t a half-hour apart. For example, when I did this, my 50-minute commute had eight waypoints, mostly represented by stoplights, four-way stops, or important turns.

Some unexpected benefits to logging when you pass certain areas include knowing when the train comes, knowing the school bus routes, knowing when businesses let their employees out, etc. Sometimes it’s possible to identify something that had always been taken for granted but can be completely bypassed by adjusting your travel time.

The key to logging the travel is to be accurate to the time displayed on the clock in your car. From day to day, you might leave at approximately the same time but perhaps not exactly the same time. Don’t worry about that. Just record the time exactly as the clock shows it. After the trip, go back and figure out the time it took to travel each segment. Do not attempt to calculate the travel time until after the trip is complete. Driving is hard enough without performing math.

Don’t expect a good average for the segments until you’ve driven the same route for a full week. By that time, you will know very precisely exactly when you will be passing specific points in your drive based on when you started the drive.

Route Congestion versus Travel Time

If you have the liberty, consider driving your regular commute at different times to see how traffic patterns vary. We’re not talking about hours apart, here. But no doubt you’ve noticed that leaving home fifteen minutes later than usual results in completely different traffic characteristics.

Why would you do this? If you are going to be working on achieving good mileage, you might want to be surrounded by fewer cars. For example, it is harder to pulse and glide when you are creeping along in bumper-to-bumper congestion. On the other hand, you will have fewer opportunities to drive at the speed you want when the few cars on the road want to drive all-out as fast as possible.

The key is to find that time when there are enough cars on the road to keep everyone at a reasonable pace but not so many that it’s a parking lot. I’m not going to tell you that such a situation exists in your area, but it might and you might not know about it.

Trip MPG

The good news is that some newer cars display the trip mileage on their own. You simply need to write it down at the end of the drive. If you have an older hybrid, however, you might need to reset the trip odometer to get the mileage for just that trip. If you have a non-hybrid, you might not be able to calculate the trip MPG at all. I say that because – unless you have another way – the only way to manually measure consumption over distance is to start with a full tank and then top off the tank when the drive is over. Since we’re talking about single-trip calculations, the amount of fuel consumed will be miniscule.

Documenting the Trip MPG is nice, but by itself, only presents a part of the story. For example, yesterday your trip MPG was much higher than today. Why? Without other variables, it might be impossible to know. Which is why you might want to also consider documenting. . .

Trip Temperature

Anyone who has driven a hybrid for more than a couple years knows that the ambient temperature really does have an impact on mileage. On the surface, it is easy to see that when the temperature is lower, the mileage is also lower. However, a little digging will reveal that the engine block cools down faster in the cold air and ran more to keep warm; the battery was cold in the morning and wasn’t running as efficient; or perhaps you were cold and ran the heater. Likewise, a hot battery pack is not a happy battery pack and you are more inclined to run the A/C when the temperature is above 90F.

And so it is that with the combination of trip MPG and temperature, the mystery of why today’s mileage is different from yesterday’s might be settled with an examination of the role played by ambient temperature.

Tank MPG

Most hybrids and some newer conventional cars maintain an average MPG that the user can reset; many users reset it when they refill their gas tank. In this way, an average for the entire tank can be recorded. Another way to record the tank average is to divide the number of miles driven (per the odometer) by the amount of gasoline physically pumped into the tank. This can confirm the car’s calculations or prove it wrong. Some hybrid drivers have proven that even if the tank-to-tank calculations don’t match, they tend to even out over time. Which is to say, the car’s calculation and your manual calculation might differ for individual tanks but over multiple tanks, both methods return a very similar calculation.

Average Tank Temperature

This one is a little controversial. I didn’t think it would be, but clearly I was mistaken. When I recorded and posted my tank-to-tank averages, I would refer to weather.com for temperature readings. Here’s what I did: in a spreadsheet, enter all the high and low temperatures for each day during that particular tank; then average all the numbers. This is the value I entered as “average temperature for the tank.” Was I actually driving at the hottest or coldest points of the day, every day? No. What about the days I worked from home and didn’t actually drive; did I include those days in my calculations? Yes. Why? I simply didn’t care enough to be that precise. The end result was, as far as I was concerned, close enough.

How Do We Document?

This one is entirely up to you. File it under “try a lot of things and go with whichever one works best for you.

Personally, I record the tank averages. There is an added convenience to this: with every fill-up the gas station gives me a receipt. On that receipt is the exact amount of gasoline I pumped to which I add the car’s reported average MPG and the odometer’s recorded distance. The amount f gasoline simply adds into the “total amount of gasoline consumed”. The tank distance is primarily used to verify the overall odometer.

A friend keeps a small notepad and pencil in his glove box. He records all the pertinent information there. He never transfers the data and refers to the notepad when he wants to look up past tanks. Since I transfer my numbers into a spreadsheet, the gasoline receipt is temporary.

How Do We Use the Measurements?

Most people keep their documents because they simply want to know their own mileage. It surprises some people have quickly a problem can be detected simply by monitoring the mileage. For example, some people have been able to determine they get better mileage with one gas station versus another. Others have been able to identify a failing 12-volt battery through a drop in mileage. Of course, if a hybrid battery is starting to fail, overall mileage could be a forbearer.

My spreadsheet started simple but became more complicated in time. I started with:

  • Date
  • Tank MPG
  • Tank Miles
  • Refill Gallons
  • Tank Ave. Temp

With these four data points, I was able to create a historical trend graphic showing tanks over time compared to the average temperature for each tank. The “Tank Miles” was only because I wanted to know how many miles I could travel on a full tank of gas.

In time, I started getting curious about other calculations such as a rolling 12-month average and the Lifetime Average MPG. With the Lifetime MPG, I can use the sum of all Refill Gallons (Total Gallons) to compare my car to any other car driven the same total distance. By using their estimated MPG, it’s easy to show how much more they spend in total fuel costs.

Here is a screen capture showing one 12-month span from August 2010 to August 2011. This format shows the raw numbers and automatically generates the chart underneath. With the temperature shaded in the background, it is amazingly easy to see the direct impact temperature has on overall mileage.

Tony Prius Mileage 2010-2011

Conclusion

Whatever your intentions, without proper documentation there cannot be proper measurement and nothing will improve. Think of it this way: if you want to tell someone you get good mileage or that you drive the quickest route, or that traffic is always bunched up this time of day, be prepared for them to say, “prove it.”

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Article,EPA,Hypermiling

Know Your Route

28 May , 2016  

-Tony Schaefer

So many times, when it comes to achieving higher mileage, people focus on their car and how they drive. Most times, they just assume the commute is an unavoidable variable. A predefined route that some days has good traffic while other days has bad traffic. This article will explain why the route you take and how you drive it plays as much a role as all other variables. When it comes to improving, never consider anything to be predetermined. The goal is to scrutinize everything.

Find a Mileage Friendly Route

If you happen to live in a large city, there’s a very good chance there are multiple options when it comes to the daily commute. Personally, I have three choices that I will call “Fastest”, “Easiest”, and “Hypermiling”.

“Fastest”: I have the opportunity to hop on an interstate for about ¾ of my commute. Doing so would save about ten minutes and is an attractive option when time matters. The downside is that the interstate maintains a relatively constant 70 – 80 MPH except when it comes to a screeching halt for no particular reason before slamming back up to 70 MPH. In other words, exactly the opposite of hypermiling.

“Easiest”: There is a state highway that runs is literally a straight shot from town to town. Albeit, one with multiple stoplights. Like the interstate, traffic is either racing along (though closer to 50 MPH), stopping for the red light, or accelerating Grand Prix style at the green light. It’s a multi-lane stop-and-go early-morning ball of stress. In no way do I look forward to starting or ending my day on this drive.

“Hypermiling”: This drive is 5 miles and 9 minutes (on average) longer than the “Easiest” route. This drive has longer stretches without stoplights and some stoplights are timed. It passes two schools and one nature preserve. The highest speed limit sign is 45 MPH. It is on this route that I see joggers, walkers, and the occasional wildlife. On nice days, I drive this route with my windows down enjoying the sights and sounds. All the while, the speed is conducive to attentive hypermiling and plays into the capabilities of my car.

By selecting a different route, I can not only achieve better mileage, I can choose how my day starts and ends. If you find that you arrive at work already stressed and you return home mentally ragged, do yourself a favor and seek out a more casual and hypermile-friendly route.

Memorize Your Route

Here is an analogy parents can appreciate. Let’s say your son goes to the first day of school and is presented with a difficult, lengthy exam. How would you expect him to score on that exam? Probably not very good. On the second day, he is presented with the exact same exam. Should he do better than the day before? Perhaps. Let’s pretend your son is presented with the exact same exam every day for the entire 180-day school year. You would expect him to be acing that exam with absolutely no effort, wouldn’t you?

Now what about people working an average 250 days per year? Most of them drive the exact same route every day, to AND from work. Even after all this repetition, it has been my experience that people drive their daily commutes as though it’s their very first time. Every time.

You are a human (I hope). You are preprogrammed to identify and memorize patterns. It’s what we do.

  • Does your commute have a string of fast food joints all next to each other? If so, every evening there’s a strong chance a hungry driver will stop and turn without signaling. Expect it.
  • Do you cross railroad tracks? Make a mental note of when the commuter train comes through. Don’t forget to consider school busses stopping at the tracks during the school year.
  • Timed stoplights? If you didn’t make it from one light to another yesterday, or last week, or last year then you’re not going to make it today. Stop accelerating full-bore as though you have a chance. On the other side of that coin, memorize the speed at which the light will change from red to green as you approach.
  • I have a round-about. I know exactly at what speed I can make that round-about without braking (on a clear day and dry pavement). Coupling this with how far back I let up on the accelerator allows me to coast to the round-about, pray for no cars, and roll through without once touching my brakes.

If you drive a hybrid, consider basing battery usage on drive segments. Pick up some charge during the fast segments in order to run farther on battery during the slow segments. Or vice versa: consider going deep into the battery pack if you know an upcoming faster segment will allow you to recharge. Recharging will impact the instantaneous mileage. Ignore that; it’s the average that matters.

It’s all about driving the same route every day, figuring out what works best, and repeating it.

Summary

If you have the opportunity, drive a route that returns the highest mileage. If it turns out to also be least stressful, then it’s a double-win. The only way to know which route is the most fuel-efficient is to document each pass in order to develop an average and recognize patterns. Once the best route is identified, memorize how to handle each segment with the intent of getting better with each day.

 

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EPA,Features,Hypermiling

Tony Schaefer on Hypermiling

19 Mar , 2016  

This is a Table of Contents page to Tony’s articles on hypermiling.  You don’t necessarily have to read them in order and this page will allow you to jump around if you want.  At the bottom of each article will be a link back to this page.

 

Group 1: Hypermiling Explained

Hypermiling Cardinal Rules

Let’s Define Hypermiling

Why We Hypermile

Group 2: Hypermiling Tips

Listen to Calmer Music

Be Conscious of How You Work the Accelerator

Braking

Try to Avoid Braking Altogether

Follow Large Vehicles (at a safe distance)

Beware of Your Car’s Aerodynamics

Know Your Route

Learn to Read Stoplights

Pulse and Glide

Document, Document, Document

Planning Trips

Group 3: Non-Hypermiling Fuel Saving

Drive Less

Beware of your Car’s Aerodynamics 

Check Your Tires’ Pressure

Hypermiling in the Social Media Age

It’s a Game of Averages

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