Read the following excerpt from cleangreecars and tell me, can you point out the flaw?
Patriot vs the Prius - Clean Green Cars
However, to get the real figure, we calculated consumption based on how much fuel each car had used over the 160 miles. The result was astonishing: both cars had used nearly identical amounts of fuel. The Jeep had averaged 38.9 mpg - only 3.1 mpg less than its computer had recorded. However, the computer of the Prius appeared to be telling whoppers: it actually achieved just 39.9 mpg - a massive 17.1 mpg less than it had claimed.It's pretty simple, if you know about the Prius bladder. You see, the Prius has a resin bladder instead of a fuel tank. Some days, you can put 8 or 9 gallons in, other days you can put in a few more. Some drivers recommend you rock the car gently to 'make more room' before you try to fill the tank some more.
So, you can't measure fuel economy off of one tank. A better test would be to run several tanks through, or just trust the computer display. (I wouldn't fully trust the computer display, but you're going to get a better estimate than this 'test' team did.)
Another point they really need to emphasize is the Patriot is running on diesel, not gas. That creates a difference in what you're comparing and they really should have done a better job in interpreting their results.
But putting that aside for now, if the testers had spent one second running their results past anyone who owns or knows about the Prius, they would have saved themselves some embarrassment. I really can't understand why they thought their results were valid. Do they think the government testing facilities are that bad? Do they disbelieve all the other sources around? Did they not look at all? Or did they really think they somehow uncovered a massive cover-up on hybrid fuel economy?
If you know about the resin bladder, you probably understand why I had to laugh when I read their conclusion.
Whereas, the first impressions of the Patriot had been overwhelmingly negative - it's an SUV with interior plastics apparently supplied by a Chinese Christmas cracker factory - it converted us by the end of the day. It had been a better experience for both driver (more pleasant to drive) and passenger (more space). Our test also raises the question over the economy of hybrids overall - a subject to which we will be returning.I hope they do return to the subject. I also hope they get it right next time.
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