http://www.triplepundit.com/2007/04/askpablo-well-to-wheel-efficiency-part-iii/ Business, Better. Since 2005 Thu, 11 Mar 2010 17:19:54 -0800 http://wordpress.org/?v=2.9.2 hourly 1 http://www.triplepundit.com/2007/04/askpablo-well-to-wheel-efficiency-part-iii/comment-page-1/#comment-14686 Tormod Thu, 10 May 2007 08:16:09 +0000 http://www.triplepundit.com/wordpress/2007/04/askpablo-well-to-wheel-efficiency-part-iii/#comment-14686 Hello Pablo I see I am arriving a bit late to the party here, but again, thank you for an excellent article. One thing I found a bit surprising is this: On average a vehicle's internal combustion (IC) engine is 37.6% efficient I thought this was a bit optimistic. This figure is probably what you can get under the most favourable circumstances, with optimal load being drawn from the engine. Can it really be applied as an average? I believe it will be different if say 100 hp is used vs. if only 20 hp is needed like in slow traffic. I see you have accounted for a portion of standby/idle, but still.. Calculating these figures are OK, but I would like to see real measured values (torque meter on the driveshaft etc.) for a "standard" commuter trip, including cold start, idling, slow traffic and everything. I would expect to see even more discouraging figures then. OK, now we have seen that the Common Car is a truly wasteful and inefficient machine. What would these figures look like on an EV or HEV...or PHEV? Or a scooter? I guess a scooter would give some interesting numbers, because I don't think the well-to-wheel is all that impressive, but it wins in the end because the payload is a much larger percentage of the gross weight. Since in the end when you get back home, all the energy has been lost in some way, I guess a more relevant figure would be to use liter per passenger-km as we say here in Europe. Then we could also compare trains, planes and boats on the same scale. I'd love to see the figures for a cruise-ship... Would any of these be interesting as a topic for your next article? Again, thank you for this and many other interesting articles. Regards Tormod Hello Pablo
I see I am arriving a bit late to the party here, but again, thank you for an excellent article.
One thing I found a bit surprising is this:
On average a vehicle’s internal combustion (IC) engine is 37.6% efficient
I thought this was a bit optimistic. This figure is probably what you can get under the most favourable circumstances, with optimal load being drawn from the engine. Can it really be applied as an average? I believe it will be different if say 100 hp is used vs. if only 20 hp is needed like in slow traffic. I see you have accounted for a portion of standby/idle, but still..
Calculating these figures are OK, but I would like to see real measured values (torque meter on the driveshaft etc.) for a “standard” commuter trip, including cold start, idling, slow traffic and everything. I would expect to see even more discouraging figures then.
OK, now we have seen that the Common Car is a truly wasteful and inefficient machine.
What would these figures look like on an EV or HEV…or PHEV? Or a scooter?
I guess a scooter would give some interesting numbers, because I don’t think the well-to-wheel is all that impressive, but it wins in the end because the payload is a much larger percentage of the gross weight.
Since in the end when you get back home, all the energy has been lost in some way, I guess a more relevant figure would be to use liter per passenger-km as we say here in Europe. Then we could also compare trains, planes and boats on the same scale. I’d love to see the figures for a cruise-ship… Would any of these be interesting as a topic for your next article?
Again, thank you for this and many other interesting articles.
Regards Tormod

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