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Old 06-30-2007, 08:08 AM
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FastMover FastMover is offline
Old Boomer Techie
 
Real Name: BobB
Location: Pacific Northwest (WA)
Hybrids: '07 TCH (Titanium)
Posts: 531
Post Re: Mid 20's in-town driving.....what gives

Quote:
Originally Posted by abward View Post
... I really do think that some TCHs are "out of wack", and if you take two TCHs, fill them up at the same pump at the same gas station, have the same driver do the same course with both vehicles, you will get two different results for MPG.
The driver is the single biggest factor, after that it has more to do with the driving environment that the car. The car is set up electronically at the same dealerships as some of those that perform better, and to identical specifications. But we cannot control the driving environment. If you need proof, look at the questions being asked in the posts here from those with higher posted FE. Anyone with high numbers will be asking about trip length/time, hills, temperature, wind, road conditions and even segment distance/time between full stops at traffic lights or stop signs. Ther may be some car differences (toe in and other alighmemt, released brake frictions, bearings, exhaust resistance, etc), but until you get into the extreme (hypermiler) efficiency ranges they make only small differences unless the car is very badly out of specification.

There are some things we can do in response to this environment. Avoid speed changes to the maximum extend possible; Anticipate stops and slow to avoid them; work to avoid any braking that may be required (this one is hard for some drivers becaue it means keeping a larger following distance, even in town); anticipate grades, both up and down, and adjust your demanded power early for more efficient total energy management (Total Enery = Speed x Mass - sometimes called inertia); plan to avoid short trips by combining errands and etc.; select routes options (freeway or hiway or street) for optimal FE.

Things that can not be controlled for most of us: Origin and Destination of trip; for the most part, time of travel, and except for a few possibilities, the route to be travelled.

Generally, smooth and slow is good in driving technique, but there are exceptions: Accelerating from a stop too slow may be detrimental, especially in a heavier hybrid; Insufficient power for an uphill grade can work against FE by forcing a lower ICE to axel ratio and working the engine in an inefficient power range (lugging).

Nost of these techniques are not limited to Hybrids or even to fuel efficient cars. They will result in inproved FE in amy vehicle. But a hybrid will better reward their use because of the greater potential for FE that in designed to the vehicle. The flip side of that is that crude driving techniques can carry a greater penalty in a most hybrids.

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It is the ignorant among us that will eventually destroy us all.

Last edited by FastMover : 06-30-2007 at 08:36 AM.
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