Hypermilers

While I visited my parents’ place in May, I came across an article about Wayne Gerdes and the MPG Challenge. This 20 mile race through Madison isn’t about speed, but rather using the absolute minimum amount of fuel to complete the course. Gerdes uses the word hypermilers to describe those who make a habit of extreme fuel efficiency. And when I say extreme, I’m not kidding. Gerdes practices a number of highly unorthodox techniques to go much father on a given amount of fuel than you or I would.

For example:

• Drive as if you have no brakes. Granted you have to use them sometimes, keep it to an absolute minimum. Does the sign suggest a limit of 30 for the exit ramp? You can probably maintain 50.
• Turn off the car when possible. And I don’t just mean when the car is stopped!
• Regardless of how hot it is, do not use the air-conditioning, and do not open any windows. If it’s hot out, Gerdes will wear a special vest full of ice to keep cool.
• Draft large vehicles on the highway.
• When the road is wet, don’t drive in the wheel-ruts depressed by countless tires over the years. These fill with water and cause a lot of drag. Instead drive slightly to the right or left, up out of the depressions.
• Parked on an incline? Released the park brake and coast as far as you can before even starting the car.

You’ve got to be pretty devoted to drive like this, and some of it sounds downright unsafe. Still, there are things to be learned from hypermilers. I’ve started to adopt a number of easy tactics and on the two tanks of gas I’ve kept track of, I’m getting at least 100 more kilometres per tank. This is an increase of more than 20%. My typical fill-up is about 55 litres and on a tank, I typically get 520 – 530 kilometres. For the first few years of the car’s life, I’d get almost exactly 635 kilometres per tank in the city. I’ve somehow dropped 100 kilometres and no mechanic I’ve mentioned it to has been able to discover the cause. Sure I expect a twelve-year-old car to lose some efficiency compared to when it was new, but this much?

So after reading about Gerdes getting more than 100 miles per gallon in a hybrid, I thought I should be able to wring more kilometres from each litre, even with my old girl.

Initially, I started looking ahead to the next stop light. If it’s red, I’ll clutch so I start coasting. The idea is that I’ll slow down enough for the light to turn green by the time I get there. This way I won’t have to stop. Certainly it’s more fuel-efficient to drive through an intersection at 40 km/h and speed up to 50 km/h, than it is to come to a full stop and then accelerate to 50 km/h. I’ve taken to looking at the cross walk indicators at approaching intersections as well. If the red hand is flashing and I’m a block away, I might as well clutch and idle the whole way there because it will change before I reach the intersection and I’ll have to stop anyway. There’s no point in rushing to a red. Even with stop signs, I clutch much earlier than I used to. I know I have to stop, but I can coast for half a block before the intersection, especially if no one’s behind me.

I also clutch on hills if they’re steep enough to maintain my momentum. On my morning commute, there’s one point where I crest a hill and am able to coast for a few hundred metres. Even better is the traffic light a few hundred metres past the bottom of the hill. If I see the light turning red as I descend the hill, I don’t bother releasing the clutch. Instead, I just let my momentum carry me to the traffic light.

I also take turns faster than I used to. Not so much with regular neighbourhood corners, but on-ramps, off-ramps, and other more sweeping turns. I used to hit the apex late in the turn to power out of it, but now I try to apex at the middle to widen the curve and maintain as much speed as possible. Carrying more momentum through the turn means not needing to accelerate to get back to cruising speed afterward.

I do believe all of these things help, but the biggest change I’ve made is adopting the suggestions we’ve seen in so many government brochures to help with fuel efficiency. I’m easy on the gas pedal. The brochures suggest a more gentle acceleration but I tend to think of the way this is accomplished: don’t press the gas pedal very far.

When on the highway, I keep the speed down. My usual practice was to drive at about 120 km/h or even faster if the traffic allowed it. Now, during the highway portion of my commute, I keep my speed to about 95 km/h using cruise control, and stay far to the right. Not only does a lower speed reduce wind resistance, but driving slower makes it easier to maintain a constant speed, which also saves fuel.

I have no evidence for this, but I believe the biggest factors in the increased economy I’ve been enjoying are the gentler acceleration and the limiting of my top speed.

Crunching the numbers after my last fill-up gave me a fuel efficiency of 7.9 litres/100 km (30 mpg) which I’m pleased with because the brochure for my car (yes, I still have it) gives a fuel efficiency rating of 9.6 litres/100 km in the city, and 7.0 litres/100 km on the highway. I figure 7.9 is a good figure for a 1995 Accord, thank you very much! I’m closer to the highway figure than to the city, and I expect to get better at it with some practice.

What really delights me is that none of this costs money. All I had to do was change my habits somewhat, and my reward is a significant increase in fuel efficiency. I went from 530 km between fill-ups (10.24 litres/100 km) to 680 km (7.9 litres/100 km) with almost no effort and certainly no cost. Despite this, I know I’m no hypermiler. Gerdes can use just 4 litres/100 km (59 mpg) in his 2005 (non-hybrid) Honda Accord! I enjoy doing the best I can, but I’m not going to shut the car off while I’m driving or leave the windows up on a hot summer day.