Thread: An Unpalatable Fact (with apologies to Al Gore!)
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Old 07-23-2008, 10:36 AM
SPL SPL is offline
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Real Name: Stanley Lipshitz
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Default Re: An Unpalatable Fact (with apologies to Al Gore!)
DesertDog — A few additional clarifying comments:
  • I think that my application of the ICE's power efficiency factor of 0.69466 to the electro-mechanical loss factor of 0.7314 may be misleading you into thinking that the latter is inordinately low, but I think that Miller's 73% number for this is probably reasonable. Even with the ICE's factor included, the overall factor is 0.50829 (i.e., ~51%), not the 41.7% you cite. I'm not sure where you get your number.
  • The additional mechanical power that needs to be provided to MG1 by the ICE is 6.84 kW (in order to get the needed 5.85 kW = 6.84 kW x 0.8554 to the NiMH battery). This is well within MG1's capability, I believe. To deliver this additional mechanical power, the ICE needs to produce an additional 9.84 kW (= 6.84 kW/0.69466), which is well within its capability too.
  • We don't actually know how the ICE's and MG1's rpm's are being apportioned (at the road speed of 40 mph) when the ICE has the additional load of recharging the battery. Without this knowledge I think we're stymied.
Another possibly relevant typo in Miller's paper is in Slide #50, where Pb should be -3.3 kW (and not -3.9 kW).

Stan
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