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CRC study finds that fuel systems in some modern vehicles fail with E15 use

30 January 2013

A newly completed study (CRC Project No. AVFL-15a) by the Coordinating Research Council, a non-profit organization created and supported by the petroleum and auto industries, has found that some fuel systems in modern vehicles survive testing in mid-blend ethanol fuels, while others will experience complete failures that would prevent operation.

The fuel pumps and level senders that failed or exhibited other effects during testing on E15 and E15a are used on a substantial number of the 29 million 2001 – 2007 model year vehicles represented by the components evaluated in the report.

A different use for ethanol: High Octane Fuels
While the conventional view of the use of ethanol has been to increase the renewable component in the overall gasoline pool, researchers gathered in Washington DC at the 2013 SAE International High Octane Fuels Symposium (HOF) to explore the prospects for a different application of the fuel: leveraging its octane properties to enable optimized engines with greater efficiency and reduced fuel consumption.
Ethanol is attractive not only for its octane properties (enabling higher compression ratios and boost), but also its cooling properties.
One scenario floated at the symposium could potentially see a decrease in the ethanol content of regular fuel; the doing away with the current middle formulation, and the creation of a new fuel—a so-called Tier III fuel—that would use mid-range ethanol content (on the order of E20 to E30) with optimized engines.
(A write-up of the symposium and the attendant issues will be coming on GCC.)

The new report represents an extension of a 2011 scoping study that investigated how gasoline containing 20% ethanol by volume (E20) might affect wetted automotive fuel system components such as pumps, dampers, level senders, and injectors. That scoping project (CRC Project No. AVFL-15) was used to identify areas where further testing should be performed.

Background. Increasing the ethanol concentration in motor gasoline has been suggested as a way to meet Renewable Fuel Standard 2 (RFS2) requirements. The US Environmental Protection Agency (EPA) has approved waivers for selling fuel containing up to 15% ethanol (E15) in model year 2001 and newer light-duty vehicles. (Earlier post.)

Various philosophical and technical grounds for support or opposition to this change have been offered, and an increasing amount of data is emerging on the impact of higher ethanol content in gasoline. While the studies published to date provide some perspective on the positive and negative impacts of E20 (where the subscript designates the percent by volume ethanol blended with unleaded gasoline) and E15, there has been little independent reproduction of published results, and gaps in the published literature remain as well.

The durability of wetted fuel system parts was probed in the Coordinating Research Council (CRC) Report Number 662. The screening study documented in that report covered a spectrum of fuel system components exposed to E20; individual components were tested in addition to full fuel systems. That work concludes that E20 fuels do negatively impact a subset of fuel-wetted parts, while other fuel-wetted parts showed no effect in screening. However, all the conclusions in [that study] are based on single or in some cases duplicate tests of a particular component/fuel interaction. A failure in a single test raises concern that vehicles in the field will at some point begin to experience similar failures.

As a rule of thumb, original equipment manufacturers (OEMs) expect part failures to occur at less than one per thousand vehicles, so a part failure in a single test is highly worrisome. Nonetheless it is possible that such a failure is a random event that results from the chance influence of an uncontrolled variable in the experiment. Furthermore, a single point test cannot give a quantitative indication of the expected frequency of occurrence, only that the data suggests (but does not prove) that the observed event is fairly likely.

—“Durability Of Fuel Pumps And Fuel Level Senders In Neat And Aggressive E15”

The new study. The primary test fuels for the new study were E15 and an aggressive blend of E15 (E15a). E15a represents the worst-case blends of gasoline and 15 volume percent ethanol that might be found in the field. E10 and E0 test fuels were also incorporated into this study in a second phase as reference points to assess the relative performance of the E15 and E15a test blends.

Automobile manufacturers developed a candidate list of vehicles for testing. Based on manufacturer suggestions, 15 designs from different manufacturers spanning the 1996 to 2009 model years were used. The study estimates that the design selections from the original scoping study represented at least 37 million vehicles with components and systems similar in construction and materials. Based on the scoping study, several fuel pumps and fuel level senders were selected for testing in the current work. The subset of parts used in the current work represents approximately 29 million 2001-2007 vehicles.

The protocols for testing fuel pumps and senders—fuel pump endurance aging, soak durability, and tear down analyses; fuel level sender resistance and full sweep aging—followed the procedures used in the original scoping study. The testing procedures were based on existing SAE and USCAR protocols which are used in the automotive industry to predict new product life.

Among the findings:

  • The pump soak test could discriminate the interaction of fuel pumps with test fuel. Some pump design-fuel combinations had no deviations in performance while other pump design-fuel combinations led to pump failures. One fuel pump model, currently in use in the field, seized in almost every replicate of the pump soak test when either neat or aggressive E15 was used as test fuel, but pumps of this model did not fail on any replicate of the same test when either E0 or E10 was used as test fuel.

  • here are pump designs (currently in use in the field) that did not seize in the fuel pump soak test, but did exhibit statistically significant flow loss when tested with neat or aggressive E15.

  • The pump endurance test could sort fuel pumps by their interaction with test fuel; some pump design-fuel combinations had no deviations in performance while other pump design-fuel combinations led to pump failure. One fuel pump model, currently in use in the field, seized in almost every replicate of the pump endurance test when either neat or aggressive E15 was used as test fuel, but did not fail on any replicate of the same test when E0 was used as test fuel. Another design of pump, currently in use in the field, was not impacted by mid-blend ethanol in the endurance test.

  • Exposure to E15 or aggressive E15 caused dimensional changes in all impellers. Depending on pump model, the standard deviation of thickness was approximately 2 to 27 times greater in E15 than in E0 at the end of the soak test.

  • The tests showed issues with the performance of the fuel level senders when tested with the E15 and E15a blends. Both the E15a and E15 blends had three instances of significant signal defects. The significant signal defects experienced (consumer observable resistance spikes) could potentially cause interference with proper OBDII function. While not consistent and not found in all samples tested, the results indicate some effect of the E15 and E15a blends on sender operation.

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January 30, 2013 in Ethanol, Vehicle Systems | Permalink | Comments (9) | TrackBack (0)

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It's astounding that manufacturers still don't have their act together, 35 years after the introduction of "gasohol" (as it was called in the 1970s).

Let's face it, the profitability of oil allows oil companies (car company=oil company) to run many scams and buy many politicians to prevent alternatives. The fact that most americans fall for this stuff is not surprising either, they have their brainwash boxes on constantly. What is most amazing is that there appears to be no one that calls BS on this stuff. The fourth estate is dead.

Does this apply to vehicles later than 2007?

Does this apply to typical pump fuel?

Does "Aggressive E15" mean it is more acidic and corrosive than real world pump fuel?

Does "Neat" mean it has NO water ?

Does "Neat" mean it is atypical of pump fuel?

Is the CRC a pro-oil group like Fuels America is a pro-ethanol group?

Kelly, where are you when we need an expert paranoid to weigh in on this?

The automotive and marine industries were dead-set against E15, but they were steamrolled by Big Corn.

E-P,

Are you familiar with Hanlon's razor?
"Never attribute to malice that which is adequately explained by stupidity."

After reading both linked reports (E20 and E15) it seems that some fielded fuel systems will indeed have trouble using E15 or E20. Others tested, however, showed no problems. So, it seems that there can indeed be non-FFV vehicles that can safely be run with these mid-range E fuels. Given the trend towards higher % ethanol fuels it seems foolish for manufactures not to anticipate and plan for this and equip their cars with proven designs that handle E0, E10, E15 or E20 fuels. Better yet, just proactively implement E85 FFV technology across the product line and be done with it. It can easily be done, just the will to do it is lacking.

I'm not attributing it to stupdity, I'm attributing it to farm-state senators pushing the interests of their campaign contributors.  They don't have to be dumb to create these problems, just uninterested in the big picture.

Back when detergent oil was first introduced in the middle of the last century there were dire warnings of oil system problems - it turned out to be no problem.

Back when "gasohol" was first introduced in the 1970s there were dire warnings of fuel system problems - it turned out to be no problem.

Now as E15 is introduced there are dire warnings of fuel system problems -

The SAE standard J1681 specifies how to test fuel compatibility with ethanol blends. Car manufacturers and/or component manufacturers are not at all obliged to follow the test protocol in this standard (quite different from the situation regarding EPA regulations, if one wants to make this comparison) but it might be good practice if they did. As said in the CRC report, the aggressive E15 blend was formulated in J1681 to represent the worst case blends of gasoline and 15 volume percent ethanol that might be found in the field. A car and component manufacturer should safely provide products that can handle all fuel qualities on the market, not only the best ones. Apparently, they do not. However, when J1681 was released, the maximum blend was E10 on the US market. Thus, E10 tolerance was sufficient then. I presume that the reason for choosing a higher blend percentage than 10% in J1681 was to provide some safety margin. With E15, this margin would be gone, albeit if the homework would have been done properly and everybody had followed the J1681 standard, the outcome should hardly have been as bad as it appears in the study. I have not studied the CRC report in detail but it seems unlikely that E15 could be used in the US car fleet without major problems. Perhaps the car manufacturers could provide lists of vehicles that tolerate E15, as has been done in some EU member states who introduced E10, but this could limit E15 to a niche fuel market.

Besides from the problems mentioned in the study, it is know that fuel permeability increases with increasing ethanol content and this causes higher evaporative emissions.

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