I took a trip this weekend to see my wife's family, 200 miles each way. It was almost exclusively highway driving, averaged 65-70 mph. I made no special effort to get good fuel economy, as my wife gets frustrated with driving slowly just to improve mpg. My average MPG for the trip was 53.0, average temperature was near 50 degrees F. This lead me to wonder: do other cars routinely exceed their EPA (or whatever other standard) fuel economy estimates? People often say that diesels are better than the Prius due to similar fuel economy and better power (or whatever the perceived advantages are). But they're generally comparing the vehicles by using EPA fuel economy. Is it likely possible for these diesels to also get in real life MPG numbers that are far better than the standardized estimates?
Hybrid, straight-up gas, or diesel -- it doesn't matter. Hypermiling can work in any car. How far it exceeds EPA estimates is mostly under control of the operator. See CleanMPG for lots of examples.
The term hypermiling is new but the act of it probably goes back to at least the 1930's. You could say with a great deal of truth, hypermiling a conventional vehicle is simply impersonating a Prius Avoiding aggressive driving - doing the opposite Often having fan-on only instead of the A/C manually shutting off the ignition at stops manually shutting off the ignition coasting to a stop manually shutting off the ignition to coast whenever it can be sustained a while
These two steps are dangerous to perform with most conventional vehicles that have power steering and power brakes. If you turn off the engine you will lose power steering, and after the vacuum reservoir is depleted you will lose power brakes. It's safer to shift to N when you want to glide, leaving the engine on. However this practice violates some states' traffic codes.
I did this for one tank of petrol in my 1990 2 litre manual Camry wagon. I used premium 95 octane petrol. I would turn off the ignition and select neutral whenever I was going down a hill. I accelerated briskly from a stop in first and second then selected 5th at 60km/h to cruise. I would select the highest gear I could at lower speeds. Engine off when ever stopped. Coasting to traffic lights with engine off avoiding brakes. Put the transmission in gear and ignition on, on slopes steep enough to maintain speed on a closed throttle to take advantage of engine braking and fuel shut-off on over run. If I slowed too much I slipped the car out of gear then shut the engine down. Corner at the highest safe speed to maintain momentum. Driving like this I got 740 kilometres from a 52 litre fill or about 7L/100km Prior to this I was getting 9L/100km After this I used all but turning off the engine except at traffic signals I was very familiar with. Doing this each tank got me a consumption between 7.5 and 8.0L/100km. All this driving was in metropolitan Adelaide, a small town of about 1.2 million people. I live in Southern Adelaide and work in Northern Adelaide, about 35 km away. The Dept of Environment lists the consumption of this car at 9L/100km city and 6.8L/100km country. As I was beating the official consumption I guess I was hypermiling I just never gave driving like this a name. After a while fuel saving driving becomes a habit.
I have changed my driving form quite a bit. My wife on the other hand is making me crazy about it. She says "you are just driving slow to annoy those behind you!" "Speed up or I won't drive with you!" I offered to let her out anytime she wishes. She hasnt taken me up on it yet.:madgrin:
Given that the hybrid-ness, or at least the battery, is used very little during steady-state highway driving, it's safe to say that the 1.5L Prius mill is good for 50 or 60 MPG on its own. It would probably do marginally better coupled to a conventional gearbox, esp. with a good overdrive that could keep it down at 1800 RPM or so at cruise. It's quite efficient. So throwing the set of hypermiling techniques at a setup with that engine and a manual tranny would probably kick butt, as long as hard stops could generally be avoided. . _H*
I think you would need something like a 12 speed gearbox and a dedicated driver to keep the engine in its most efficient range. Even on the highway there are rises and dips.
I would not recommend to anybody experiment with this in rush hour traffic, but CleanMPG has not had any accidents among their 3000 members doing this. It's interesting to note that from 2000-2004 I've been in five collisions while driving aggressively...since then just one accident from a hit and run drunk. Hypermiling if anything has gotten me out of at least two accidents and two traffic tickets.
2008 Package 6 Prius. As I understand it, that's still a few MPG lower than what many people on here average.
53MPG is not unusual for Prius on mainly highway drive (with less inclines) and some tail-wind for assistance.....(or less head-wind to begin with).
The EPA lists the Mazda 5 at 25 mpg highway, but I averaged just under 36 in a spring break trip (VA to FL and back) this year. I keep the tires a few PSI over the recommended value, drive near the speed limit, shift to N (manual transmission) when possible, drive gently, and try to drive behind trucks (best) or enormous SUVs (better than nothing), shooting for just under a 2 second following distance. And turn it off at stoplights. Nothing too aggressive. You wouldn't know I was doing anything differently from any other car on the road. People complain about the "hybrid premium" when simple driving style changes with no money cost can result in significant gas savings. Most people don't need new equipment, they need a little self-control. Or maybe just a little education. During the 1st and 2nd oil crises, I recall TV pubic service ads and print ads talking about how gentle driving saved gas. I can recall a picture of somebody driving with an egg between their foot and the gas pedal, to get the point across. I've seen the occasional magazine/website article on this, but have not yet seen the equivalent of a coherent public awareness campaign surface with the current $100/bbl oil. You have to wonder whether fuel use reductions per dollar invested might be as high or higher there than with the CAFE/flex fuel sham we currently have. It really helps to have a ScanGuage or equivalent to give instantaneous feedback on MPG and engine load, mostly to remind you not to push the engine too hard. There have been bills in Congress that would have mandated fuel economy gauges in cars, for the expected gas savings, but so far none have passed. Attributed to strong opposition from US auto makers. That's a pity. Barring that, I wish the EPA would offer a higher MPG rating for cars with gauges. I recall that, at some point in the distant past, VW got the MPG on the Rabbit up-rated just for having a vacuum-gauge shift light to tell you want to upshift. Seems like in todays market that might be enough incentive to get those gauges put in.
As far as the original question. Yes, it is relatively easy to beat the EPA numbers. In order to make the EPA highway mpg number more "realistic" the EPA runs the car through its test loop (on a treadmill), calculates the mpg, then reduces the number by 20%. So, the EPA actually achieves 20% better mpg in their testing than what they post on the vehicle. However, the EPA does not drive faster than 55mph in their tests.
This was roughly true in the past but is no longer no longer the case. The EPA re-tuned the test to represent lead-footed (ie, typical) driving habits. Here's a summary in the NY Times, max highway speed of 80, average speed 62 in the new tests: http://www.nytimes.com/2007/09/16/automobiles/16MILES.html
Well, I joined this site when I still owned the anti-Prius (2001 Nissan Pathfinder LE 4WD). I tried everything to improve the mileage, including shifting into neutral at lights (scangauge read lower l/hr consumption), coasting (in gear) to lights, no warmup, reduced speed on highways, etc. etc. I saw no difference in my mileage. That vehicle used to use fuel to ensure it's powerful engine would meet EPA specs re emissions. While it wasn't too bad for a 4400 lb AWD vehicle, it still used 2-3 times as much fuel as Pearl. Between 14 and 18 l/100 km depending on season and whether city or highway - and it was Premium! The 80 litre tank would cost over $100 to fill now!!! So I don't think the statement "you can hypermile any vehicle" is quite accurate. The anti-Prius at least will fight you all the way. It's designed to guzzle. And the computer is faster and more connected to the vehicle than the driver.
Keep in mind that trying to hypermile a vehicle that boasts 12mpg may not provide you with large numeric gains like it does with high MPG cars like the Prius or HCH. IE you may see a 1-2mpg gain from hypermiling the 12mpg truck but a 7-10mpg gain by hypermiling a Prius. The net gain in that 2mpg gain from the truck would be similar in the amount of fuel used in the 7mpg gain in the Prius. My point? Don't let a low numeric gain get you down when hypermiling a gas guzzler. Do the math first. 53mpg is pretty easy for me to attain now (without trying hard) but I could see how it may be difficult for those with a different commute.
