http://www.merinews.com/catFull.jsp?articleID=147907

In this case, I'm sort of with the Auto Show but it does show a real problem. How do we evaluate mixed power source vehicles using MPG, a relic of ordinary gas only vehicles. I don't know the answer but we're going to need something that makes sense and is fair.

LATE THOUGHT: If GM and/or Chrysler go out of business, will the new hybrid companies like AFT Trinity, Fisher and Tesla be able to 'buy a factory' to retool for their products? Would we see a resurgence of innovation in an industry that seems to be a little 'behind the power curve?'

Bob Wilson

After April 3, use e-mail to contact me:

I saw this at Prius Owners Group and passed it along to CleanMPG. Gerdes et al. are going to the LA Auto Show and I suggested that they take a side trip to wherever AFS decides to hang out their sign.

It would be interesting to know more about that prototype. Vague impression that it uses compressed air power in some fashion, but I can't open their web site at the moment.

DAS

They have a mixed ultracapacitor and battery system:
http://www.afstrinity.com/xh.htm

The ultra capacitors handle the problem of high current charge and discharge that heats and ages our batteries. But ultra capacitors require a sophisticated control system. AFS appears to have addressed that hard problem from the beginning. This page also shows how they calculated 150 MPG.

AFS is claiming 20% of the mileage would be under gas engine mode at 30 MPG and assigns no MPG for the 80% under plug-in power. From an energy standpoint, this is wrong because the plug-in power has to still come from an energy source. It is the same nonsense GM tried by claiming E85 was only 15% gasoline so the ethanol is 'free'.

I'm beginning to think $/mile is the only useful measure. This takes the form of energy out of the equation. It works for diesel, air, plug-in, CNG, or any other form.

Bob Wilson

After April 3, use e-mail to contact me:

$/mile won't work very well either, because it is too variable to make any meaningful comparison. Even if the tech remains unchanged, price changes will make comparisons (over time) meaningless. My car did not suddenly become 30% more efficient since August.

$/mile works as a budget estimate, but not as an efficiency estimate.

You are right, though, that it can serve as a reality check on folks claiming that ethanol, or electricity from the mains, should count as 'free'.

Now I'm embarrassed because since I've gotten my 03 Prius, I've been working on:

• graph of MPG vs speed
• graph of drag power vs speed
• graph of engine power vs fuel

These are not definitive and would need a little clean-up but charts like these would be perfect for engineers shopping for a vehicle:



Now this would really make me happy. However, my wife is more '$' oriented.

I would be happy if the first chart showing the MPG vs speed were plotted with "$" values vs. steady state, standard day, cruise with some well defined "$/gallon" and "$/kwh."

Actually, you've given me an idea for a pair of charts that combines these two core charts into one by using a variable scale, engine power X-axis to map the engine fuel consumption into the upper chart. This would address a question raised in another thread by someone who interpreted higher engine rpm as 'transmission slippage.' Thanks!

Bob Wilson

After April 3, use e-mail to contact me:

We need to meaure a car's efficiency in kWh per mile.

You can convert this to other energy units.

You need to track energy per mile.
Nothing else really matters.