Hypermiling - an introduction

Hypermiling.
You may have heard the term.
So just what is it?

"Hypermiling" has a couple of different meanings.

It can be either:

1. Driving to achieve the best possible fuel efficiency from a fuel powered vehicle,
   OR
2. Driving so as to exceed the "official" fuel mileage for the vehicle.

From a "green" perspective, the second meaning is the most practical.
We can't all afford to buy a new "super economy" motor vehicle every few years, so getting the most from what we already have is important.

Whatever motor vehicle you have, it will have a "official" fuel consumption. Although the test standards vary a little from country to country, the difference is not that specific. Remember, you are trying to beat the "official" figures for YOUR car in your country, not for other cars or other countries.

Example: my automobile is a 2006 Citroen Berlingo Multispace, with a 1.6 litre turbo-diesel engine rated at 92 hp. It is a European model, and the "official" fuel economy has been calculated under the European standards.
(In case you think that gives me an advantage over the USA, it is universally believed that the Euro method of fuel calculation for new cars gives a more economical mpg figure - some would say a figure very hard to achieve in "real" use - so it is actually easier to "hypermile" a car measured by the US system of fuel economy!)
The official figures are:

• Urban (aka town and city driving) 42.2 mpg (Imperial), 35.1 mpg (US), 6.7 litres per 100km
• Extra-urban (out-of-town driving) 60.1 mpg (Imperial), 50.0 mpg (US), 4.7 litres per 100km
• Combined ("average" driving) 52.3 mpg (Imperial), 43.5 mpg (US), 5.4 litres per 100km

And, in case you are wondering, it's a 1300kg (c. 2850 lbs), 5 seat vehicle, not some superlight "eco" car (I had two of those from '94 to '04 - and they weighed only 650kg! (c. 1430 lbs)). So it is a very economical car for its size (which is why I bought it!).

But this article is about how to get better fuel mileage from ANY motor vehicle, so it doesn't matter if you have an economical car or a gas guzzler - there is always the opportunity of saving a bit of fuel :-)

So what kind of fuel mileage do I get?
Well, on a run of just under 300 miles (which I make a couple of times a year), using mostly main roads and motorways (expressways) in light to moderate traffic, and driving carefully, not exceeding about 60 mph (96 kph), I can get a bit more than 70 mpg (58 mpg US, 4 litres/100km).

Now that's "hypermiling"!
I'm getting (in that example) around 16% more miles out of every drop of fuel than the official standard.

So that's what I get under "ideal" conditions.

What about more "typical" mileage?

Well, the fuel computer on the car says I am currently getting 64.2 mpg overall (that's 53.5 mpg US, 4.4 litres per 100km).
So I'm still "hypermiling" :-)

Top tip for hypermiling is ... drive a bit slower!

• If you usually drift over the marked speed limit for a particular road, then make sure you don't! Driving just 5 mph (8 kph) slower makes a very noticeable difference!
• Take your foot of the gas just a couple of seconds earlier when you approach a junction, so you let the engine save fuel and slow you down a bit, rather than braking heavily and late (don't drive like a race driver!)
• Don't floor the gas pedal when moving away from a junction - build speed up more slowly.
• Leave a bigger gap between yourself and the vehicle in front, so that you can take your foot off the gas and just slow down a bit if you need to, rather than having to brake everytime the vehicle in front slows up a bit.

What about the "worst" case scenario - driving to work in heavy traffic, starting with a "cold" engine, and covering just a few miles?
Well, I actually get the best fuel mileage of all for that scenario - since I changed jobs a bit more than a year ago (swapping a 25 mile each way off-peak commute for a 1 mile each way commute), I haven't used the car for work at all!
I cycle the mile to work in less time that it would take me to drive, use no motor fuel at all, and keep fit all at the same time!

Links:
my best gas mileage on a "real" journey
tips for improving your gas mileage (aka fuel economy)
hard evidence for the link between speed and gas mileage