Wednesday, September 8, 2010

Hypermiling, can it be done?

This will be my first entry that isn't based on a specific car, but rather reviewing a type of driving. These days hypermiling seems to be one of the things that's in to save your fuel costs with the car you already have. There are variations of this technique, a few of them can be useful for your regular driving providing you with savings benefits by just altering your driving behaviour. The reason why fuel economy ratings have to say they can vary is primarily due to the way people drive, if you drive with a lead foot you'll never reach those numbers you might get a significantly worse fuel mileage than less efficient vehicles not being driven so hard.

I did probably my best hypermiling run on a 2010 Chevrolet Impala LT, its the base model but it comes with a 3.5L V6. Its also a rather large car which isn't ideal for a hypermiling run. The good news however was I was running it on essentially an empty tank on reserve fuel(needle under E) and had to drive this car another 10 miles or 16 kms. The reason why the nearly empty tank was a good thing was, due to the lower weight. Filling up your car to full will make the car heavier and forces it to consume more fuel just to push this weight around. Now the most efficient way of actually hypermiling is to actually select neutral, get out of the car, push the car so that it starts rolling, while rolling start the car. The reason for this is it requires more energy, thus more fuel to move an stationary object basically inertia. However practically this can be dangerous, should your car not start, you essentially have a car moving with no power. A powerless car means, no power brakes and no power steering which is terrible news if your about to hit an object. As a precaution and for everybody's safety...don't do this.

I take a less extreme way of hypermiling. Another instance where I don't follow the extreme rule of hypermiling is not stopping. If you encounter a stop sign, you legally must stop but assume you don't look at the law, to get the most out of each drop of gas stopping is bad. I urge anybody every trying hypermiling to follow the stop sign rules. Now one of the worst ways you waste fuel is acceleration, to hypermile you must actually accelerate rather slowly. The most important gauge to you will have to be tachometer, the best you can keep the tachometer reading below 2000 rpm, the less harder your engine works and the more fuel you save. Reading the speedometer won't help, you just won't be accelerating quickly enough to net a speeding ticket, you are trying to save fuel after all. If you accelerate this way, I guarantee you'll be passed very quickly I even got passed by a bus. Please keep to the curb lane(the right lane on any country where the steering wheel is on the left, vice-versa for the other countries), this way you're respecting other motorists by staying in the appropriate lane. By the time you need to make lane changes you'll be traveling at speed limit making the change easy.

When you approach an intersection with a red light, lightly brake early and try your absolute best to at least be moving before you must stop. By doing so you not only save fuel by not dealing with less interial mass, and you also don't have to work the car as hard to return to the speed you need to travel at. When traveling downhill, let go of the accelerator pedal as your car will stop sending fuel yet you'll still travel at speed(possibly faster depending on the hill) thanks to gravity. When going up the hill you may want to increase speed early as you have to fight gravity and also if your driving a manual prevent stalling, keeping watch of your tachometer is most necessary. Ideal efficient speeds may vary, 60-70 km/h(35-40 mph) is typically the ideal speed to travel at. For most people highway mileage is better, although 100 km/h(60 mph) isn't when the engine runs at its most efficient level. The good news about highway driving is under normal circumstances you shouldn't have to stop. Keeping to the outer lane while maintaining speed limit is your best bet of achieving very good fuel economy numbers.

Having done this, there are only a few things that affected my run. There was an occasional person who cuts you off, this is bad as your forced to brake harder and it'll take longer to retain speed. If you can read the traffic, you may be able to avoid these drivers by anticipating them either by cutting off their path or brake early preventing harsh braking if you're unable to. Traffic is the worst thing to encounter on a hypermiling journey, if you know a way around the traffic that doesn't increase the distance of your driving by a lot then take the longer route. Sometimes you can be unlucky where traffic lights are against you, like they were in my case constantly stopping and taking a long time to regain speed. In my case my car wasn't in great shape, thus it overheated for an unknown reason forcing me to pull over. Despite these problems I still managed according to the car's computer got 5L/100 km this translates to roughly 47 mpg US or 56 mpg imperial. This was mostly city driving, with a stretch of highway driving. This is definitely double the fuel consumption of what the Chevrolet Impala is rated to do.

Would I change my habit of driving having achieved a pretty good number for a first timer? I'd only change a few things. The reason being, I found accelerating very slowly to be rather stressful. I found that constantly worrying about the tachometer, worrying about stopping and worrying about how traffic felt about my driving to be distracting as well. If someone behind you isn't too happy about your slow acceleration they'll definitely cut you off, adding danger to himself and yourself. Here's what I would change in my driving that doesn't affect safety or stress.

1) When approaching a red light, ease off the accelerator and brake gently. If you still approach the intersection and its still red, that's fine you at least reduced brake wear if nothing else. If it goes green, you deal with less inertia and its actually faster in the long run. It makes you think that driving quickly to the light is idiotic, bad for brakes, bad for your fuel consumption and its hard on the engine lowering your car's lifespan and you'll be passed that instance since a car driving at some speed can reach higher speeds easier than doing it from a stop.

2) Keeping an eye on your tachometer once in a while will help judge whether you drive too hard or not. I find anything below 3000 rpm to be the best balance between adequate speed and isn't that much worse for your consumption. If your driving on the highway this can help you increase your car's range from filler station to the next.

3) Good route planning can eliminate the fuel killing traffic stops. The best route gets you to your destination quicker and will be more fuel efficient. The less lights to stop at, the less 0 mpg moments you'll have in your drive.

4) Toss out anything you don't need in your car. If there's a big heavy box in your trunk that isn't useful to bring along then don't bring it. All you really need is emergency equipment should you need to pull over because there's a problem with the car or in the event of an accident. Not treating the car like a garbage bin would also help as litter isn't useful in any way.

Something that isn't mentioned as often as a good way to hypermile, maintain your vehicle to as good condition as possible. A healthy car can produce better fuel economy numbers than a poorly maintained car. Cleaning the air filter is one area where a poorly maintained vehicle will consume more fuel for instance. Fighting off rust will eliminate the possibility of your fuel lines or the fuel tank from corroding which produces leaks. Timely oil changes will allow the engine to work more smoothly, failing oil changes results in the engine working harder and heating up as the oil is a lubricant. Making sure your O2 sensor is working can mean the difference in good fuel economy and bad fuel economy. If you're noticing worse fuel economy, you may need to change your spark plugs as they're supposed to ignite the fuel in your engine. Keeping your tires at the correct tire pressure is useful, most newer cars have them listed on one of the labels on the driver's door, this piece of maintainence is good for the tire life and your fuel consumption and shouldn't cost a penny. Doing all these things not only help your fuel efficiency, but extend the life of your vehicle.

Hopefully some of these tips have been helpful. I speficially chose the items I felt you didn't need to truly alter your driving style. Yes it would be nice to double your fuel economy every single run, but I'd rather spend a little bit more fuel knowing my driving in the long run is less stressful and crucially safer. Any gain in fuel economy is beneficial to pretty much everybody except the oil company, if they're going to get your money anyways why not try your best to give as little as you can.


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