Back in March the EPA (Environmental Protection Agency) announced a plan to cut the amount of sulfur allowed in gasoline. In the “small print” was an audacious reversal of policy that seeks to solve the three leading ethanol challenges in one move with higher compression.  The idea is deep in the 938-page text of the proposed Tier 3 rule, which would lower the amount of sulfur in gasoline by two-thirds, to the level required in California

First, the American fuel market is saturated with ethanol, almost all cars are not tuned to efficiently burn it and the fuel consumers are leery of the fuel’s properties due to these issues and a parade of mis and dis information.

These issues plus the Congressional renewable fuel mandate have the EPA looking at, well, some common sense – make the most of the properties of ethanol.

Back in the day, late 1960s and very early 1970s “high compression engines” was the norm, running better than 9 to 1 and “muscle cars” 10 to 1 and higher.  But the urgency to finally get the very toxic lead additive that raised octane in gasoline out of the market plus the oil embargo shocks killed both the compression ratios and crushed a healthy automotive industry.  It’s been over 40 years in the reversal of policy.

The EPA’s proposal is for a fuel that is 30 percent ethanol (E30) that could reduce tailpipe emissions and improve fuel economy – and even encourage drivers to use more ethanol.

The New York Times quotes Mercedes-Benz senior engineer for fuels policy in the United States William H. Woebkenberg saying, “You make the dog like the dog food.”

Before the hair stands on end and the hackles rise lets have a look at the situation.  Today’s typical E10 pump blend is 10 percent ethanol and 90 percent gasoline.  The advantage is it adds some octane, enough for today’s low compression engines and adds a bit of oxygen for pollution control.  The flexible-fuel vehicles that can use E85 formulations offers little financial or performance benefit – they are still tuned to run on low octane E10.

Using high-octane gasoline in an engine that does not require it offers no benefit.  Turned around, burning low-octane gas in an engine tuned for high octane can cause erratic combustion from pre-ignition called knocking that can result in severe engine damage.

In engines designed to compress the fuel-air mixture to very high pressures before igniting it with the spark plug, high-octane fuel burns predictably and can produce much more horsepower.  A blend of 30 percent ethanol and 70 percent gasoline E30 would be octane rich enough to take advantage of ethanol’s strengths.  An engine tuned with a compression ratio specifically for E30 would perform better on E30 than on the standard E10, creating a market incentive.

The idea has widespread support among technical experts, as there is a powerful incentive in the EPA plan: offering automakers the option of having their cars certified on E30.  That means the data on the vehicle’s pollution output and fuel economy given to the EPA for certifying with E30 would call for engines optimized to take advantage of the E30 blend’s octane rating of 93 or perhaps even higher.

There are a couple bugs in the idea.  It would require big investments at gas stations for blending pumps and storage tanks.  The oil companies have opposed and resisted using higher concentrations of ethanol. The oil industry is always lobbying Congress to change federal rules so they can use less ethanol, not more.

The various engine and fuel experts like the idea because it takes advantage of the good characteristics of ethanol, including an octane rating that is well over 100.  Plus the E.P.A. is inviting the auto companies to comment without a surprise mandate.

Another NYTs quote comes from Margaret Wooldridge, a professor of mechanical engineering at the University of Michigan saying, “That’s getting smarter. The way ethanol is used now if anybody does notice there’s any ethanol in the fuel, it’s always in a way that is negative.”

An E30 blend in an engine designed to use that fuel would be attractive to car buyers with “ridiculous power and good fuel economy,” said Mr. Woebkenberg.  Who adds owners of those cars would seek out the fuel, unlike owners of flex-fuel cars.

Flexible Fuel vehicles never really caught one.  Wooldridge explains while they can run at blends of up to 85 percent ethanol, they are still mostly optimized for gasoline, not ethanol.  Even though there are millions of FlexFuel vehicles on the road, they run mostly on E10 because that is a better bargain for the driver.

C. Boyden Gray, a former aide to President George H. W. Bush who is now a Washington lawyer representing energy clients is quoted by the NYTs saying, “I hope that the E.P.A. agrees to do it.”   Over the coming years more cars are going to be engineered for high-octane fuel so they can get better fuel economy as automakers move to double economy, and high-octane fuel with 30 percent ethanol is cleaner than blends relying more heavily on gasoline.

There is sure to be a fight.  The EPA would probably have to do more than just give automakers the option to certify vehicles on E30; it would probably have to mandate its availability to give car shoppers confidence that they would be able to refuel such vehicles.

Its been over 40 years waiting for regulations for basic engineering principles to be reapplied to engine design.  Its an idea way ovedue.


5 Comments so far

  1. JeffC on May 7, 2013 6:42 AM

    E30 drivers would have to seek out the fuel because they couldn’t run on E10 …

    the EPA needs to get out of the Ethanol business …

    CO2 is plant food not pollution …

  2. JohnMc on May 7, 2013 12:16 PM

    Well I guess the EPA does not want anyone to eat corn. At the prices it will be at once implemented no one will be able to afford it.

  3. jpstraley on May 8, 2013 10:04 AM

    Ford Eco-boost, buy it at your corner Ford store! Direct injection, turbo. Super gas mileage! Compression ratio is 10.5:1 .

    Small bore engines with the basic tricks: DI, turbo, variable valve timing, good internal friction control, proper assembly….you don’t need more ethanol to use CR even higher than 10.5. (Soon to come, supercritical FI)

    On balance, I would expect the environmental damage from additional corn production to feed the EtOH plants to balance any tailpipe advantage.

    Why not butanol instead of EtOH? Does EPA consider this alternative?

    Indeed, is there really a benefit of taking very small amounts of S out of gasoline fuels? What do the refiners say? Do they care, as the costs will merely pass through. These last increments are very expensive to remove, and it’s my wallet from which the costs will come.

  4. Barney on January 20, 2014 10:53 PM

    Thanks for sharing the information about the high compression engines. The engine restoration is an important thing for the vehicle users. Keep sharing the information like this in the upcoming pages.

  5. Jay on August 3, 2014 8:35 AM

    Thanks for all the information on high compression engines. I realize how important it is to know all this stuff when you’re restoring engines yourself. I like working on cars in my free time as a hobby. Keep the info coming, because I’m always looking to learn more!

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