1 July 2008
As petrol prices soar around the globe, a whole new breed of driver is beginning to emerge. In the non-metric US, they've been named 'hypermilers', and they'll do anything to save themselves money at the petrol pump. In fact, many claim to have halved their fuel consumption simply by changing their driving habits and, in this age of high prices, we could all do with following their example.
Certainly, if you race from every set of traffic lights, you will use up fuel unnecessarily, but equally, if you accelerate too slowly you can also use too much because the engine is under load for longer. The key is to pull away steadily and, if you drive a manual, change gears at the right time to improve your mileage. The optimum time to change up is at about 2500rpm for a petrol-engined car and 2000rpm for a diesel. In an automatic, ease back on the throttle once the car has gained enough initial speed.
You can also waste fuel by slowing down too suddenly. Look ahead and anticipate the flow of traffic rather than planting your foot on the brake at the last second. Idling is also uneconomical - don't switch on the ignition until all passengers are on board and switch off the engine if you're caught in a heavy jam.
In normal driving, the more you maintain your momentum, the less you will have to use the accelerator, the biggest fuel burner. Take advantage of a downhill run (without speeding) to help climb the next hill. On the open road, drive at a moderate speed - an extra 20kmh over the speed limit can mean up to 25 per cent higher fuel consumption.
Is it more fuel-efficient to have the windows down or the air-con on? While the air con uses fuel, the open windows cause drag. According to the government's Green Vehicle Guide, air-con is a better option at speeds above 80kmh. Try to stop the car heating up in the first place by parking in the shade, but if it's hot, wind down the windows for the first part of the journey and then the air con won't need to work so hard.
At the end of each trip, empty the car of the kids' toys, the toolbox or golf clubs and remove roof racks, bike racks and storage boxes when they're not being used. Don't tow a trailer unless you really have to - it'll add to aerodynamic drag and result in higher fuel bills - and make sure your tyres are properly inflated.
Know what your fuel consumption is. Reset your odometer to zero every time you fill up the tank and note the number of kilometers covered when the tank is ready for a refill. To get a litres/100kmfigure, divide the number of litres it took to refill the tank by the number of kilometres travelled, then multiply that by 100. See how your driving style affects your fuel bill over a month or so and you'll soon be a fully-fledged hypermiler.
