My Nerdy Life

 

Hypermiling: Save Fuel by Driving like Zoolander’s Grandpa

Driving is always a bit of a social experiment for me. I always find it interesting to see just how ridiculously inefficiently people drive. On top of that, I see so many people driving huge SUVs, trucks, and other gas guzzling monstrosities. Of course, the obvious answer to this problem is to simply avoid driving altogether and buy small fuel efficient vehicles, but for a lot of people moving closer to their work or buying a new car just isn’t something you can do at the drop of a hat. Regardless, you can drastically improve fuel consumption by altering your driving (and parking) habits.

 

In my 2009 Honda Civic, I use an average of 5-7 L/100 km (47-33 mpg) in mixed city driving (depending on the season and if I have winter tires on or not). That’s between 10-35% below my car’s Canadian fuel consumption ratings for mixed driving (7.7 L/100 km; 30 mpg). The nerdy term for treating gas like it’s liquid gold is called hypermiling, and today I’ll cover some tips to save fuel so you can become the hypermiling ninja of your roadways!

So here’s the thing, the internal combustion engine is horrendously inefficient and it’s a wonder why it still exists, let alone has become the most common form of powering transportation. At BEST a modern engine only averages about 18-22% efficiency, and that’s including all the latest electronics, turbo-chargers, and direct injection (excluding hybrid/electric/hydrogen). What’s worse, the absolute maximum efficiency limit under purely theoretical ideal conditions is 37%. That means we waste around 80% of the energy available in fuel, and hypothetically can’t get better than 63%!!! These kinds of figures are beyond alarming. If it wasn’t for the cheap cost of fuel when the engine was first invented, no one in their right mind would produce anything with only 20% efficiency. Imagine making an airbag that only inflates 20%… Don’t worry sir, it won’t save your life, but it will give you a nice pillow to rest your head on during the crash.

The problem is the laws of thermodynamics make it impossible for the standard internal combustion engine to exceed certain limits. The majority of energy is lost to heat, which is why engines get so hot. To get around that engine designers invented radiators and fans, but those only put more load on the engine and waste fuel… so it’s a terribly ill conceived concept if you think about it. I’ll spare you the math, but if you’re really interested go check out the Carnot Cycle. Also, fun fact: refrigerators are just engines in reverse!

Alas, until automotive companies finally abandon internal combustion engine (e.g., Tesla) we must make the best of what we have, so without further adieu let’s get to the tips!

 

1. The Low Hanging Fruit

I include these for completeness, but it should come as no surprise that ensuring your tires are properly inflated, using slow acceleration, and combining errands will save you fuel. That’s the standard (and entirely valid) advice that’s always touted on media outlets, but since you’re a nerd, you already knew that right? Now lets move on to the fun stuff!

2. Don’t Turn Left

To save fuel, you must become the Derek Zoolander of driving and avoid turning left whenever possible!

What on earth does turning left have to do with fuel economy?

I’m glad you asked! If you think about it, turning left is a horribly inefficient way to drive because of all of the waiting you have to do, which means more idling, which means burning more fuel. This can be especially bad during rush hour when you have to wait what seems like an eternity for the opposite lane to become clear so you can cross over and turn. On top of that, when there’s only a small gap between cars you have to floor it to make it in time. Not only is that more dangerous, but it uses way more fuel. It’s no wonder that shipping giant UPS has spent millions of dollars optimizing their delivery routes, in part, to avoid making left turns (another link). Most North American (European too I think?) cities allow right-hand turns at red lights, which means UPS drivers only have to make left turns 10% of the time. If they can do it, so can you!

On a larger scale, every time someone stops in a lane while they wait to turn left, the cars behind them also end up stopping and idling. So not only are you burning more fuel, but so is everyone else and traffic flow is disrupted. Not to mention people HATE delays while driving, so waiting for someone to make a left turn just makes people cranky, which guess what, burns more fuel! Speaking of which, it’d be interesting to see what the impact of feel-good soothing music/radio would be on fuel consumption and accident rates… anyone want to conduct a large scale traffic experiment?

3. Park in a Garage and/or Use a Block Heater

Up here in the great white north, it tends to get cold during the winter. With temperatures dropping down to -30 C (-22 F) at least a few times out of the year, cold starts can be tough on engines. Extremely cold temperatures can also wear out your battery faster and you’ll burn nearly double the fuel for the first few minutes. If you have one, parking in an attached garage can greatly help with this issue (bonus if it’s insulated). My garage almost never dips below freezing even when it’s brutally cold outside. So I can’t help but chuckle when I see the suckers who park in their driveways and have to scrape ice off their windows in -30 at 7:00 am, and then get into a freezing cold car. At least half of the people on my street park on their driveways and fill their double-car garages with crap instead, which makes no sense to me. In the summer time, parking in a garage also means your car will be in the shade and won’t turn into an oven!

A block-heater will also help with cold starts. If you go that route, I’d suggest using a timer so it’s only on for an hour or two before you have to go. In many places, public/employee parking lots also have plugs for block heaters, so be sure to take advantage of them.

In terms of ‘warming-up’ your car, most newer cars only need 30-60 seconds of idle time. After that, just drive gently (which of course you’d be doing anyway) until your vehicle warms up. Another bonus strategy is to time your errands near the warmest part of the day, so the big ball of hydrogen/helium gas that we call the Sun can help warm up your car.

4. Use Synthetic Oil

Further to the previous point, among other benefits, synthetic oil is less likely to turn into molasses in cold temperatures. Many newer vehicles now come standard with synthetic oil because of the lower viscosity (i.e., flows easier), which reduces friction on the engine, which in turn burns less fuel (anywhere from 1-5% depending on who you ask). This is true at all temperatures, but for cold starts this can be especially significant during those first few minutes of driving. The lower viscosity also means your engine will be able to lubricate itself more easily and ultimately improve engine life.

5. Drive like you Don’t Have Brakes

Okay, don’t actually drive without brakes, but pretend like it costs you $5 every time you use them, or have your spouse whack you across the head every time (just wait until you’re not driving, safety first! haha), or go Top Gear style and connect the brakes to your horn/radio to blast some obnoxious sound every time. In any case, the point is to minimize the use of your brakes, because every time you do you’re effectively throwing away fuel!

Be proactive with your driving and look ahead… really far ahead. Don’t just pay attention to the car in front of you, but look a kilometer down the road at the next 10 cars in front of you, the lights, pedestrians, merge lanes, hills, off-ramps, etc.

If you’re in bumper to bumper traffic, don’t just mindless stop and start, give yourself a little extra room, put the car in gear, and crawl along at a constant speed.

If you see a green light in the distance and you know you’re not going to make the light, take your foot off the gas and coast (safely) to the light. If you time it right, the light will change to red and back to green by the time you arrive, so you only have to slow down rather than stop.

If you’re approaching an interchange/off ramp, start coasting early so you can reduce your speed enough to coast through the interchange without braking.

Going down a big hill?  If it’s steep enough that you need to brake, leave the car in gear and coast, letting the engine brake for you. In newer cars the engine will actually stop injecting fuel, meaning you’ll be burning nothing! If it’s not very steep and you’re trying to maintain speed, go into neutral (only if it’s safe and legal to do so) and coast. This way you’ll only burn the fuel needed to idle the engine.

Approaching a light on top of a hill? Let the hill do the braking for you and coast up to the light.

6. Lose Weight

No, I don’t mean go on a diet, although that would help your fuel consumption too. I mean get rid of any unnecessary junk in your car. Still have those sandbags, winter shovel, extra warm clothes in your car… in July? Get rid of them, as the more your car weighs the more fuel you burn. What about that camping gear you left in the trunk because you were too lazy to do it the day you got back? Get rid of that too!

Bonus tip: in the summer months, never fill your gas tank past half-way. Every litre of fuel weighs ~1.6 lb (1 gal = 6.2 lbs), so 50 L = 80 lbs.

7. Keeping Cool

Sometimes, it’s really hot outside and your car can become a greenhouse. Although it might be tempting to blast the AC, if you’re just driving around town, you’re better off just opening the windows. For speeds above 80 km/h (50 mph), use the AC, as the increased air resistance will be worse than using the AC. Better yet, cycle your AC usage to moments when you need to decelerate. The AC compressor will put load on your engine and cause you to slow down quicker.

Heading to the beach, but don’t want to return to a hot oven? Park under a tree in the shade. Bonus: the paint on your car will fade slower if it’s not in direct sunlight.

8. Park at the Back of the Lot

Conventional parking lots are one of those other things in life that just don’t make sense. First off, the lot entrance is often at the opposite side from the store entrance, aka more fuel; second, you have to try and find a spot, aka driving around using more fuel; third, you then have to perform jiu jitsu level maneuvers to get into a tight spot between two giant SUVs, aka the Austin Powers 64-point turn; fourth, usually you have to back out of the stall, rather than just drive forward, aka more jiu jitsu level maneuvers that use fuel; and lastly, then drive back across the parking lot to get out, aka more fuel!

Although you can’t do much about the parking lot design, you can choose to park at the back. There’s always less cars, so that reduces or eliminates the need to drive around and look for a spot, and requires less fancy maneuvers to get in/out of the stall. There’s also a decent chance you can find a pull-through spot, so you can avoid having to back out later. Bonus: you get a little exercise walking to the store. Double Bonus: less chance of someone banging into your car with a door, a shopping cart, or another car.

9. Low Pressure Sucks… Literally it Does!

50% of your cars power goes towards pushing itself through the air, so air drag is extremely important. Strangely, (outside of racing/high performance cars) only more recently have car manufacturers started putting serious efforts into improving car aerodynamics. The Tesla Model S for example, is one of the aerodynamically slipperiest high-volume production cars available today, which is part of the reason why it get’s such incredible range from it’s batteries.

In terms of aerodynamics, there are two culprits: high pressure and low pressure air. More specifically, they can be culprits depending on where they are in relation to your car. If you’re trying to push high pressure air (i.e., like the front of your car) it takes a lot of effort, conversely high pressure beside/behind your car doesn’t make it harder to move your car forward. You could think of water as being high pressure and normal air as being low pressure. Just imagine how much more difficult it is to push water around than air.
On the flip side, low pressure behind your car causes drag (swirly part in the picture). This is because the turbulent air behind your car creates a pocket of low pressure, which quite literally, is trying equalize itself with the surrounding air by sucking everything into it. The problem is it also tries to suck your car (backwards) into the low pressure pocket to fill the space.

On the other hand, this is also why slip-streaming/drafting works. If another vehicle behind you was able to get near or even inside the low-pressure pocket, it would literally pull the car along. But more significantly, it would reduce the amount of air that the second car would have to push out of the way. In reality, the two cars would have to be very close together to take advantage of this, so it’s not recommended for obvious safety reasons, but you may see some fuel economy benefits if you drive a safe distance behind a semi-trailer.

In some ways, a car an also act like a very crude airplane wing. The curved top and flat bottom create lift because the pressure above the car tends to be lower than below the car. Some car manufacturers are even starting to put plastic covers on the under bodies of cars to try and smooth out airflow below the car and reduce the low pressure pockets to improve fuel economy.

So what does all of this mean? It means aerodynamics are important, and is definitely something to keep in mind when purchasing a new vehicle. It also means being conscious of anything you might add to your vehicle that will alter the aerodynamics. So don’t go driving around all winter with a bike/cargo rack on your car if you’re not using it (not to mention the extra weight). Consider getting a hitch/trunk mounted rack instead of a roof mounted one to reduce drag.

10. Don’t Idle

If you’re stopped for more than 7-10s, it’s more efficient to shut off your vehicle. Of course, I wouldn’t suggest doing this in the middle of an intersection, but if you’re waiting for someone or traffic is at a standstill due to an accident, shut off your car (assuming it’s legal in your area)!

11. Don’t Accelerate Going up Hills

Accelerating going up a hill can easily double or triple your fuel consumption. Even maintaining speed is a bad idea. Instead, reduce speed slightly (5-10 km/h) going up hills (without doing anything illegal or being an annoyance to other drivers) and gently resume your speed going down hills.

12. Car Modifications

I personally haven’t tried these, but some people go as far as modifying their cars to improve fuel efficiency. Things like:

• Covering up the grille in the winter so the engine stays at a more optimal temperature (too cold is less efficient). Some manufacturers have started adding grille shutters for this reason too
• Adding spoilers/fins to smooth out air flow
• Covering up rear wheel wells (think old-school Cadillac or Honda Insight)

What did I miss? What tips and tricks do you have for saving fuel?

Thanks for stopping by!

 

I am not a professional driver or instructor. None of the above tips/recommendations/advice/techniques should be performed without proper knowledge/instruction. Some or all of them may not be feasible or legal in your region. Please consult with local laws first. Individual vehicles may not exhibit some or any of the above listed fuel economy benefits, even if performed correctly.