Leaner engine operation…higher operating and component temps…decreased CO emissions…higher idle speeds…increased NOx emissions…erratic operation…complete stalls with E15 and E20 gasoline blends. Look for more details upcoming here on poweretblog and in the Jan/Feb. issue of Power Equipment Trade, but I’ve just gotten my hands on the impressively titled “Effects of Intermediate Ethanol Blends on Legacy Vehicles and Small Non-Road Engines, Report 1,” a study prepared by the National Renewable Energy Laboratory for the U.S. Dept. of Energy, and want to share some of the results.
First—this is a looooong 136-page report, complete with a serious number of eye-glazing charts and graphs that would put all but the most avid small engine technophiles into deep slumber. No, I haven’t read every word of it—probably never will—but managed to read the summaries of the small engine section and also the scope of the study and some of the charts, basically hitting the high points. (If you want your own copy, you can download it here.) So let’s go:
The study, which began in late summer 2007, tested E0 (unblended), E10, E15 and E20 ethanol gasoline blends in a “pilot study” to identify emissions levels and any specific, immediate operational problems with each fuel blend, followed by a “full-life” study in which the engines were run for extended periods of time on each fuel blend. The study is just that—not a comparison, but a chance to view engine operation in a controlled environment with higher ethanol blends and observe the results. Products tested were Honda, Briggs & Stratton and Kohler generators, a Briggs power washer, Poulan blower, Stihl residential grade trimmer, Weed Eater blower and a Stihl commercial grade trimmer.
EDITOR’S NOTE: The following test result information reflects product performance in a completely new fuel environment under rigorous conditions. Each product tested has fared well in the marketplace under previous and current fuel formulations—and in fact the products were selected for their high sales volume and widespread use by end users in the marketplace. Knowing the competitive nature of the industry, I could see how some are liable to use these results to slam competitors. But before you do, all you wide-eyed product managers out there, let’s pour some E15 or E20 into your fuel tank and see how your product fares during 24 or more hours of constant operation! This is basic research in a completely new fuel environment, of utmost importance to the small engine industry, and the results should be viewed as breaking new ground, not a reflection of conventional product performance.
According to the report, “Performance varied considerably among the engines tested, regardless of the fuel used. Therefore, it is not possible to completely isolate the effects of ethanol on operability. However, a few observations are noteworthy:”
- As ethanol levels increased, leaner engine operation was observed in all of the tested engines, as indicated by decreased CO emissions.
- Temperatures of both the exhaust and engine components increased as ethanol levels increased.
- HC emissions generally decreased with increasing ethanol, although increases in HC emissions occurred in some engines.
- NOX emissions increased with higher levels of ethanol in all engines; however, combined NOX + HC emissions (which are regulated as such) were tempered by decreasing HC emissions in most cases. Net changes of HC+NOX with increasing ethanol ranged from –36% to +41% and were engine-specific.
- CO emissions decreased with higher levels of ethanol.
- With greater ethanol content, three handheld trimmers demonstrated higher idle speed and experienced unintentional clutch engagement. The increased speed was again caused by the fuel:air mixture enleanment, which can be adjusted and mitigated in some engines.
- Residential and Commercial Class I and Class IV engines were aged to full life. The residential Class I as well as the commercial engines exhibited no sensitivity to ethanol from a durability perspective in the short duration of this project. The effect of ethanol on the durability of the residential Class IV engines was not clear given that a number of these engines failed during full- life aging regardless of fuel type.
- No materials compatibility issues were observed in the short duration of this project, but they were not specifically characterized as part of this study.
Another section of the study looked at specific products and engine operation:
- In the pilot study, the Briggs generator began losing power on E20 at full load, leading to an interesting discussion of whether some of the plastic carb components had swollen due to ethanol exposure and restricted fuel flow. Tests with other blends were “without incident.”
- The Poulan leaf blower, in the pilot study, began to “run poorly during aging with E15 at about 34 hrs. The engine ran very poorly during the final E20 phase.”
- In the Stihl FS 90 trimmer’s pilot study, “The (unit) ran poorly on E20, and high idle speed on E15 and E20 led to clutch engagement at idle.” The report notes that during the full-life study, the problem was corrected by altering carburetor settings and reducing idle speed.
- The Honda EB3000c generator’s full-life study noted that with E20, the engine was “‘bouncing off the governor’ at light loads when testing began…However, after 250 and then 500 hours of aging on E20, the engine ran normally at all loads.”
Again, what’s posted here is just a very, very small slice of the overall report, and what I thought readers would find interesting. This is also just a small first step in a lot of research and work for the small engine industry to adapt to new fuel blends in the marketplace. Look for more developments and comments from industry officials in future poweretblog posts and in Power Equipment Trade magazine.
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Very good post and lengthy. My dad and I have wondered if the ethanol harmed our lawn equipment over a period of time.
The engine may run fine, but it’s rubber components will fail in time from the corrsion caused by the ethanol costing end users, particularily commercial users, more in maintenance costs and lost dollars because of down time. Another brilliant idea brought to us by the corn lobby.
We own a powersports/lawn and garden store and have seen more effects on lawn and garden engnes than powersports engines.We are having fuel lines deteriate internally and fuel needle valves swell and in many cases stick closed.Ethanol is defenatly causing problems for our industry.
You should see the work orders since E-10 showed up in March. We have had one station out of ten that stuck with selling non-ethanol fuel. After nine hard months of getting the word out by us,our customers who have seen and paid for the issues it’s caused, and the local auto and marine dealers who have ,also saw countless problems with their customers.We now have only four stations still selling E-10 and there’s no waiting in line at those stations.
We have seen issues with fuel lines,diaphrams,inlet seats and needle tips,o-rings,seals and even fuel filters dissolving ,Not to mention the water and corrosion issues. It has cost my customers a lot of money and there is no since in it.
Can’t we all just go back to eating corn like we used to do?
The spread of ethanol-blended retail gasoline is one thing we’re looking to get a handle on in a future blog or magazine report: How fully it’s penetrated various markets around the U.S. Here at powerETblog headquarters, E10 wasn’t widely available until August 08 in the greater Montgomery tri-county fuel market, and I’m betting a lot of homeowners won’t be seeing ethanol issues until mower startup season next spring.
One note: When I was driving around looking to take the ethanol stciker photo for this blog post, I ran across a Chevron station still selling the good ol’ unblended straight stuff gasoline. With prices as low as they are now, I’ll probly start getting my gas there until they either switch to blended or the inevitable price upturn occurs.
Gasoline has been the bane of the small engine industry since the early 70′s (our first energy crisis). Your April 08 article, Consumer Education Reduces Fuel-Related Service Issues, is be far the most comprehensive, useful, printed offering I have seen to date. Perhaps the biggest problem with gas today is shelf life. In the southern tier of NYS we are provided with gas that will not function in 2-cycle engines in as few as 10 days. We, in the business I own, have been preaching the issues of “old gas” for years.
Well, ya’ll might as well get used to the idea of methanol, thank you Californi-eh.
Here in NY we’ve had the stuff for the 2nd year now. Most of the fuel lines that were going to wilt, have, and have been replaced with newer and more resilient stuff. (Example: Stihl FS55 with the green fuel line vs. the original black line). Now it looks like everything is running leaner than ever with the Ethanol.
Before this it was MTBE destroying Tecumseh’s Walbro carbs (they needed to fix their metallurgy, such as the Keihin on the Honda’s). The problem is, our industry generally runs slow, because there is not much $$ feeding it! Research and development costs lots of $$$$ that frankly is just not there, thanks to big box stores discounting of everything. That will only get worse with chinese knockoff stuff. And now, Tecumseh apparently will not even exist as a company after this year (2008). fun fun.
For years, and now more than ever, we have been telling everyone to:
1. Use high test fuel (93 octane).
2. Keep fuel no longer than 1 month.
3. Shake can every time you use it.
4. When you empty the can, check it for water and debris. Keep it clean.
5. Use only high grade premix (Stihl, Remax, Amsoil….)
6. No cheap gas stations (I don’t care what anyone says; I had a customer repeatedly kill his stuff on Stew_arts fuel, after he changed to a reputable brand, no more piston/ring/cylinder scores!)
The life of the fuel was a significant problem prior the the introduction of “corn squeesins” a good preservative “we use seafoam” extends the usable life to 3-4 months comfortably and tends to moderate the agressive chemical reaction as oxidation of the fuel occurs.
Where possible , we try to richen the mixture a little more agressively to prevent the lean running seen with the hotter burning blends. Sometimes the carburetors require jet modifications, and we reduce the idle and sometimes reindex the choke mechanism to cause a richer burn. This probably defeats the purpose of the blend, but we minimize comebacks.
Fuel lines have been a big problem. We recently changed to a Tygon type product across the board. I don’t know if the light exposure due to the lines being clear is good or bad chemically, but it sure makes it easier to see if you have a fuel supply issue.
Since the beginning of the 2006 mowing season E10 is all that I have used. And I have had no problems that could be traced to fuel.
Ethanol will play havoc in any fuel system if it sits up for any length. The boating and marine industry is currently making a big fuss about the use of Efuel engines.
Stabil, however, appears to be tapping the market with an “ethanol” fuel treatment that will treat the Efuel.
How does the introduction of stabilizers affect the percent of ethanol content, especially when left over the winter
I’m not an expert by any means, but the way I understand it, fuel stabilizers mainly serve as anti-evaporative agents to reduce oxidization, thereby keeping fuel “fresh” longer. Adding a stabilizer wouldn’t affect “percent of ethanol content” at all except only slightly by volume.
The anecdotal evidence I’m hearing is that even though fuel stabilizers help, it’s not advisable to store fuel more than a month, two at the most, with E10, and especially not with higher blends such as E15 and E20. It’s shaping up to be a big consumer education effort by manufacturers, distributors and dealers.