Quote:
Originally Posted by jkv357
Interesting quote from Craig Vetter about "riding style" on the last Craig Vetter Fuel Economy Challenge -
Bottom of this page: 2011 Craig Vetter Fuel Economy Challenge rules discussion
" Speaking of the way we really drive...
Rumor has it that one (or more) of the Challengers exhibited an usual (I believe he meant unusual) riding style. I don't know if there is an official name for it but it is best described as follows:
"Speed up and coast. Speed up and coast. Speed up and coast...."
Apparently, this technique is known to produce superior fuel mileage. But is it the way we really drive?
I don't think so.
Would you drive your car this way with your family?
Would you drive this way with a Highway Patrolman right behind you?
I don't think so.
Who'd have thought this might be an issue?
Effective immediately, no more "speed up and coast" style driving."
Isn't it surprising that one of the largest supporters of high mileage cycles isn't familiar with, and doesn't approve of, the Pulse and Glide technique?
How could Matsu achieve 470 MPG back in the 80s without it? He even disassembled the trans to add a neutral available from top gear.
I don't get it...
Jay |
Maybe it's because Craig would like to separate driving technique from vehicle efficiency. I don't think anyone here would argue the point that each improvement has it's individual merits, but to properly compare either improvement they must be considered separately.
The Automotive X prize contest did basically the same thing.
Personally I have always advocated the incorporation of the techniques perfected in hypermiling into the vehicles operational capabilities and power train configuration. In essence a car or truck that hypermiles itself, using a pulse a glide technique that does not equate to a change in speed of the vehicle, which uses the mass of the vehicle as capacitive storage, but requires changes in speed, to a form of energy storage that is efficient enough to allow for storage and release of energy effectively enough to take advantage of BSFC points for the engine regardless of the sum of losses at any individual vehicle speed.
With the current 15 MPH average speed specialized vehicles approaching 11,000 MPG, using the burn and coast (engine off) technique it would be an unfair comparison if one driver relied on hypermiling skills to achieve a better overall mileage.
The funny thing is as aero improves, engine efficiency falls further from the best BSFC unless higher overall drive ratios are applied. Thus one benefit is somewhat countered by a corresponding decrease in efficiency. Capacitive storage allows this situation to be resolved, but it requires extreme efficiency in wheel to wheel and power plant to wheel efficiency, assuming in the case of wheel to wheel that there will be situations where regeneration is effective.
regards
Mech