THE HIGH COMPRESSION GAMBIT
October 16, 2012 § 7 Comments
The foremost American electric car battery company, A123, declared bankruptcy today. A high flying MIT spinoff, honored by the President at the big house, bestowed with DOE funding to the tune of over $200 million, is on skid row. I am sure the Pundits will weigh in with what this might mean. But it certainly is a datum point that fits in with the lackadaisical sales performance of the electric cars. And it appears to offer support for what I am dubbing The High Compression Gambit by Mazda.
Mazda has made a few moves that signal an explicit strategy to defer electrification to the future. They have introduced a line of cars with high compression ratios operating on conventional gasoline. In my book, Shale Gas: the Promise and the Peril, I advocate the design of high compression engines to take advantage of the high octane ratings of the three viable gasoline substitutes, ethanol, methanol and methane. I suggest piloting through the armed forces, a la the Hummer. It seems as if at least one company is willing to take the plunge and not wait for anyone to lead the way.
But Mazda’s move appears to have nothing to do with enabling the gasoline alternatives. More below on how we can avail of that, no matter their intent. They were shooting for higher engine efficiencies to enable the latest CAFÉ standard to be met. Since the design started years ago, somebody was reading excellent tea leaves.
Conventional gasoline fueled cars have compression ratios (CR) of around 9:1. For a discussion of this parameter, see a previous blog. Regular gasoline experiences premature fuel ignition at higher compressions. What Mazda did was to make the cylinder narrower and longer. But the critical innovation was to provide two injections of fuel during a single cycle. The second injection is right at the point incipient knocking. The evaporative cooling drops the temperature enough to prevent premature ignition. This allowed them to increase the CR to 12:1. Fancy exhaust system management allows them to another notch up to 13:1. For 14:1 they need to use premium gasoline. They are offering this only in Europe. They believe American consumers will balk at the fuel premium, which is around 30 cents in most states.
The Mazda3, offered with just the junior version of 12:1 is reported to improve mileage from the 24/31 City/Highway to 29/39. There is some arm waving on manual versus automatic transmissions, improvements to the latter, and so on. But these are big improvements with no change in the gasoline. This appears to be the gambit. Keep improving the efficiency of the engine to help with the CAFÉ targets and kick in the electric capability when things get more viable.
We have opined in earlier blogs that electric cars, and hybrids for that matter, needed battery costs to drop to under $200/KWh and range to improve. The demise of A123 is not a promising note, but they may still be a factor. Continental Airlines went bankrupt twice before it became a value leader.
As we have noted before in these pages, improving efficiency is the fastest way to reduce emissions. The same gratification for less fuel used. I was not able to locate the predicted mileage for a Mazda3 with CR of 14:1. The benefits diminish in non-linear fashion at the higher CR’s. But it needs 95 octane gasoline.
Now for the punch line. Both E85 and M85, respectively with 85% ethanol and methanol, rest gasoline, will certainly do the job. My favorite is methanol. The evaporative cooling with M85 will be even more effective than with gasoline. In fact, compression ratios of 16 or 17 ought to be possible. Also, it is dramatically cheaper with low cost shale gas and can also be made from coal or biomass, all for lower cost than ethanol from corn. At today’s natural gas prices the cost of methanol is under 45 cents per gallon. With half the energy content of gasoline it is still much cheaper.
So, consider that at today’s regular gasoline price of $3.80, a compact car will have a fuel cost of 10.8 cents per mile (35 mpg assumed). With the same assumptions on range, M85 today will cost 5.8 cents per mile. Because of the units we are using, the energy content penalty of methanol is already counted. The consumer would have to refuel every 200 miles instead of the 350 miles assumed for the gasoline case.
For the CR 14:1 vehicle the comparison would be with premium gasoline. That would raise the cost per mile to about 11.7 cents, while the M85 would remain the same because the 15% gasoline component need only be regular gasoline.
If M85 were available, Mazda could bring the 14:1 car to this country, make the small modifications required to tolerate ethanol and methanol, and allow consumer choice. The driver could use premium gasoline or E85 or M85, whichever was available. Obviously, at the numbers shown above they would demand M85. This would set the ball rolling for the true future: some portion of passenger vehicles with CR’s of 17 running on M85 and many others with CR’s of 14 or so with fuel choice. Oil derived gasoline would be rendered just another option, a step towards reducing oil to merely a useful, not a strategic, commodity. When that happens, OPEC will be defanged as a manipulator of oil price.