UNITED STA T ES ENVIRONMENTA L PROTECTION A G ENCY NAT IONAL VEHICLE AND FUEL EMISSIONS LABORAT O RY 2565 PLYMOUT H ROAD ANN ARBOR, MICHIGAN 48105-2498

OFFICE OF A I R A ND RA DIA T ION

CISD-10-24 (LD-AFC, LDV, LDT, HDV, HDE) October 28, 2010 SUBJECT: Updated Certification Guidance for Fuel Converters Dear Manufacturer: This guidance letter, with its Enclosure, supplem ents the guidance contained in EPA Dear Manufacturer Letter CISD-09-14, dated June 20, 2009, which m a y be viewed at: http://iaspub.epa.gov/otaqpub/display_file.jsp? docid=20194&flag=1 Inf o rm ation in this docum ent am ends the June 20, 2009 guidance by adding a question and answer No. 22.2 at the very end of the Enclosure. EPA has received inquiries concerning our policies for converting vehicles to full battery electric, in particular whether such c onversions should be certified as protection from a possible tam p ering violation. This letter addresses this issue by stating that conversions to full battery electric (no on-board source of com bustion em issions) do not require alternative fuel vehicle certification. Questions regarding this letter pertaining to light-duty vehicle conversions should be directed to Martin Reinem an at reinem an.m artin@epa.gov

. Questions regarding heavy-duty vehicle and nonroad engine conversions should be directed to Steve DeBord at: debord.steven@epa.gov

. Sincerely,

Karl J. Sim on, Director Comp liance and Innovative Strategies Division Of f i ce of Transportation and Air Quality EnclosureEnclosure to CISD-10-24 Questions and Answ ers The answers to the questions presented here are based on 40 CFR Parts 80, 85, 86, 88, 600 and the Clean Air Act as Am ended. Questions applicable to all types of fuel conversions 1. What is the distinction between vehicle certification and engine certification for aftermarket fuel conversions? Are the EPA contacts different? Ans

. Vehicle certification is required for new vehicles up to 14,000 pounds gross vehicle weight (GVW ) using Otto cycle engines. Ve hicle certification is also required for new diesel cycle vehicles with GVW up to 8,500 pounds. New diesel vehicles between 8,500 and 14,000 pounds m a y be optionally certified using either chassis test standards and test procedures, or engine test standards and test procedures. Engines in vehicles of any fuel type with a GVW over 14,000 pounds GVW m u st be engine dynam o m e ter certified. Since the certification weight class requirem e nts have changed over tim e, fuel converters should exam ine the Original Equipm ent Manufacturer’s (OEM) application for certification to determ ine if a given vehicle or engine was originally vehicle or engine certified. Fuel conversions m u st be certified in a m a nner consistent with how the OEM certified the vehicle or engine. If the vehicle was chassis certified the fuel conversion m u st also be chassis certified. If the vehicle has an engine certification, the fuel conversion m u st be engine certified. Vehicle certification of fuel conversions is adm i nistered by EPA’s National Vehicle and Fuel Em issions Laboratory in Ann Arbor, MI. The EPA vehicle certification contact is Martin Reinem an. His e-m a il address is: reinem an.m artin@epa.gov

. Engine certification of fuel conversion is adm i nistered in EP A’s W a shington, DC office. The EPA engine certification contact is Greg Orehowsky. His e-m a il address is: orehowsky.gregory@epa.gov

. 2. When must vehicle fuel converters begin certifying through EPA’s Verify data system? Ans

. Vehicle converters are required to subm it applications for certification through the Verify data system beginning with the 2010 m odel year. For m o st converters, applications for 2009 m odel year certificates of conform ity w ill continue to be processed outside of Verify. Inform ation on the Verify data entry process m a y be found at: www.epa.gov/otaq/verify/publications.htm

. To receive inform ation and updates about the Verify data system sign up for the Verify Listserver at:http://www.epa.gov/otaq/verify/docum ents/420b07002.pdf

. 3. Is the EPA certification and data entry process for converting engines to alternative fuels the same for converting vehicles to alternative fuels? Ans

. No. Heavy-duty highway engines are currently certified though the FileMaker based Inform ation Managem e nt System (IMS). Inform ation on the engine certification and data entry process can be found at: http://www.epa.gov/otaq/hd-hwy.htm

. 4. The Verify data entry process is complex as are the EPA vehicle and engine certification processes. Does EPA provide assistance to fuel converters who are new to both processes? Ans

. Yes. The Verify helpline is available to assist with Verify data entry issues and m a y be contacted by e-m a il at: verifyhelp@csc.com or by phone at: 888-890-1995. The EPA certification staff can address m a ny questions about the certification process, but fuel converters new to the process m a y well benefit from the assistance of technical consultants who are f a m iliar with certif ication testing requirem e nts and with preparation of the docum entation required for EPA applications for certification. 5. Where does one find information on federal or state tax credit or rebate policies for aftermarket fuel conversions? Ans

. Inform ation on federal tax credit policies m a y be found at the Internal Revenue Service web site: http://www.irs.gov

. W h en at that website, search for “alternative fueled vehicles.” Inform ation on individual states’ policies with respect to credits and rebates m u st be addressed to the state in question, likely through that state’s tax or revenue agency. 6. What are the OEM's positions on warranty coverage for vehicles converted to operate on alternative fuels? Ans

. The OEMs differ on this issue, and warranty coverage m a y change over tim e. Therefore, vehicle owners should exam ine the language in their OEM warranty to understand the specific warranty coverage and responsibilities applicable to their vehicle. 7. Is the certification process the same for any aftermarket conversion, regardless of alternative fuel type? Ans

. Yes. Fuel conversions of OEM vehicles to any alternative fuel m u st follow the requirem e nts in Part 86 of the Code of Federal Regulations (CFR). However, there are inherent differences am ong fuels that can affect test procedures and other detailed fuelspecific requirem e nts that are not explicit in the regulations. For exam ple, test fuel specifications for E10 and E85 are not defined in Part 86, Subpart B. Therefore, it isimportant to discuss specif i c testing issues that are not explicitly described in the CFR in advance with an EPA certification representative. 8. Have there been any changes to the EPA onboard diagnostics (OBD) approval process for aftermarket fuels converters? Why is OBD compliance for fuel converted vehicles so important? Ans

. No. Fuel converters are responsible for m eeting the EPA OBD regulations in 40 CFR § 86.1806-05 and 86.007-17. Converters m u st dem onstrate that afterm arket changes to the OEM fuel control system have not aff ected MIL (m alfunction indicator light) illum i nation thresholds and that the OBD system will continue to f unction properly while operating on the new fuel. Converters m a y contact EPA with specific OBD questions. A functional OBD system is im portant in a ny vehicle, including a converted vehicle, to alert the vehicle owner to m a lfunctions that could cause excessive em issions. States with vehicle inspection program s rely alm o st comp letely on interrogating the OBD system to ensure that there are no em issions problem s. 9. Is the EPA certification process for aftermarket fuel converters the same in California or states that have adopted California vehicle emission standards? Ans

. No. California has it' s own requirem e nts for afterm arket fuel conversions. Conversions of new vehicles in California are adm i nister ed through California’s light-duty vehicle and truck certification staff. The contact for ne w vehicle certif ication in Calif ornia is Duc Nguyen, who m a y be contacted at: dnguyen@arb.ca.gov

. Conversions of in-use vehicles are adm i nistered through a different departm e nt. The contact for these vehicle conversions is Rose Castro, who m a y be contacted at: rcastro@arb.ca.gov

. For states other than California that have adopted pr ovisions or standards from the California vehicle em issions program , contact the individual state in question to learn the specifics regarding their policies on fuel conversions. 10. How does the EPA “test group” concept relate to the real world vehicles? Ans

. The concept of “test group” was created for vehicle certification purposes and is not necessarily easy to associate with “real-world” groupings of vehicles. Test groups typically include vehicles with nearly identi cal engine, em ission control, and fuel system design characteristics. OEMs designate test groups at the tim e of certification. The characteristics OEMs m u st evaluate when placing vehicles in test groups can be found in 40 CFR § 86.1827. Examples of OEM test groups are listed in the Green Vehicle Guide under the colum n heading “Underhood ID.” You can download the guide at: http:/ / www.epa.gov/greenvehicles/Download.do11. Given that converters may use the same basic fuel system design across multiple model years, various manufacturers, and various model types, is it possible to certify a product for several OEM test groups or engine families? Ans

. Yes. Under certain circum stances EPA will now allow fuel converters to com b ine certain OEM test groups into a single fuel converter test group on a case-by-case basis. EPA will allow converters to com b ine OEM test groups if criteria in 40 CFR §§ 86.1820

- 01 and 86.1827-01 are followed. EPA will consider allowing OEM test groups to be com b ined if the following criteria are m e t for each fuel converted test group: 1) Sam e original m a nufacturer and m odel year 2) Sam e OBD group 3) Sam e vehicle classification (e.g. LDV, LDT, HDV) 4) Sam e com bustion cycle 5) Sam e engine type (e.g. piston, rotary) 6) Engine displacem ents within 15% of largest displacem ent or 50 CID, whichever is largest 7) Sam e num ber of cylinders 8) Sam e arrangem e nt of cylinders 9) Sam e fuel type (e.g. diesel/gasoline) 10) Sam e fuel m e tering system (e.g. throttle body injection vs. port injection) 11) Sam e basic catalyst construction (e.g. m e tal vs. ceram ic substrate) 12) All converted vehicles are subject to the m o st stringent em ission standards used in certifying the OEM test groups. 13) The fuel converter exercised good engineering judgm ent when com b ining OEM test groups. Advance EPA approval is required for fuel converters to com b ine OEM vehicle test groups. EPA m u st also approve the selection of a worst case test vehicle am ong the com b ined OEM test groups. Fuel converters m a y need to contact EPA to determ ine if the OEM test groups are in the sam e OBD test group because this inform ation is not typically publically available. EPA will also allow fuel converters to com b ine certain OEM heavy-duty engine fam ilies into a single fuel conversion test group. EPA will allow converters to com b ine OEM engine fam ilies if the following criteria are m e t for each fuel converted test group: 1) Sam e original m a nufacturer 2) All converted vehicles are subject to the m o st stringent em ission standards. For example, 2005 and 2007 heavy-duty diesel engines m a y be in the sam e fam ily if they m eet the m o st stringent (2007) standards. 3) Sam e service class (e.g. LHDDE, MHDDE, HHDE) 4) Sam e com bustion cycle 5) Method of air aspiration6) Engine displacem ents within 15% of largest displacem ent or 50 CID, whichever is largest 7) Sam e num ber of cylinders 8) Sam e arrangem e nt of cylinders 9) Sam e fuel type (e.g. diesel/gasoline) 10) Sam e fuel m e tering system (e.g. m echanical direct or electronic direct injection) 11) Sam e basic catalyst/filter construction (e.g. m e tal vs. ceram ic substrate) 12) The fuel converter m u st use good engineering judgm ent when com b ining OEM engine f a m ilies 13) Sam e OBD group after 2013. 14) Sam e em ission control technology (e.g., internal or external EGR) Once you have identified the engines to be included in the conversion test group, select the highest em itting engine, pre-conversion, to be the test engine for the group.

12. Where can one find which manufacturers have been issued EPA certificates for aftermarket vehicle and engine fuel conversions? Ans

. Certificates for afterm arket vehicle conversions m a y be viewed on the EPA Docum e nt Index System (DIS). The DIS search field called “m odel year” refers to the year in which the certif icate is valid. Theref ore, m u ltiple EPA m odel year searches m a y be necessary to find conversion certificates for a particular OEM m odel year vehicle. Inform ation on the DIS is updated periodically but you m a y need to contact EPA or the fuel converter directly for m o re recent certification inform ation. Afterm arket alternative fuel certificate holders for a particular EPA m odel year m a y be viewed by going to: www.epa.gov/dis

. W h en at the DIS: Select “Certificates of Conform ity” in the list of Docum e nt types Select “Alternative Fuel Conversions” in the list of Industry types Select the desired EPA certificate (not vehicle) m odel year from the Model Year list Select “All” in the Manuf acturers list Select “Search” OEM certificates m a y be accessed in a sim ilar m a nner by selecting “Light-Duty Vehicles and Trucks” in the list of industry types instead of “Alternative Fuel Conversions,” and by selecting the desired vehicle m a nufacturer instead of “All” in the Manufacturer list. Certificates for afterm arket engine conversions m a y be found at: www.epa.gov/otaq/certdata.htm

. 13. Where can one find the OEM or fuel converters’ applications for certification? At present, applications for afterm arket conversion certificates are not on the DIS, butwill be in the near future. OEM applications are posted on the DIS and m a y be accessed as f o llows: Select “Applications” in the list of Docum e nt types Select “Light-Duty Vehicles and Trucks” in the list of Industry types Select the desired EPA m odel year from the Model Year list Select the desired OEM m a nufacturer from the Manufacturers list Select “Search” Vehicle certificates and applications not found on the DIS m a y be obtained by contacting EPA’s Freedom of Inform ation officer Fred Hart at hart.frederick@epa.gov

. Inform ation on heavy-duty engines not published on an EPA website m a y be obtained through the Freedom of Inform ation Act by contacting Robert Doyle at doyle.robert@epa.gov

. 14. Does EPA have authority to conduct in-use testing on fuel converted vehicles and engines? Ans

. Yes. 15. Is a Vehicle Emission Control Information (VECI) label required to be displayed under hood for an EPA certified fuel converted vehicle? Is there a similar requirement for Engine Family labeling of fuel converted engines? Ans

. Yes. The conversion kit installer m u st apply a second VECI label next to or near the original OEM underhood VECI label, which should rem a in in place. The secondary VECI label is a requirem e nt for all EPA-certified fuel converted vehicles. States that have vehicle inspection program s m a y deny registration if there is not a valid VECI label which links the fuel converted vehicle to an EPA certificate. The label should clearly indicate which fuel the converted vehicle operates on, the nam e of the m a nufacturer of the fuel conversion system , the installer of the afterm arket fuel system if different from the fuel system m a nufacturer, the converter’s test group nam e for the specific vehicle, and the date the conversion system was installed. There are analogous labeling requirem e nts for converted engines. 16. Do you need to obtain a certificate of conformity to convert nonroad equipment and stationary engines to alternative fuels? Ans

. Yes. Since EPA’s certification policies for non-road sources and stationary sources ensure comp liance with em ission standards for the full useful life of the regulated em ission source, certification is required to dem onstrate com p liance with em ission standards when converting a vehicle to operate on an alternative fuel. 17. What are EPA’s fuel conversion policies with respect to vehicles outside of EPA’s defined full useful life?Ans

. EPA policy exem pts alternative fuel converters from the Clean Air Act prohibition against tam p ering if they obtain a certificate of conform ity for the conversion. However, the certification process m a y not be appropriate for vehicles outside their regulatory full useful life. EPA recognizes this inconsistency and has initiated a rulem a king process to update the policy. The rulem a king will identify alternate regulatory pathways for exemption of legitim ate alternative fuel conversions from the prohibition on tamp ering. During this interim period while we reconsider our existing regulations, current policy rem a ins in place. This m eans that until a new policy is finalized, no certain protection against a tam p ering charge exists for converter s of outside useful life vehicles. A prudent course of action for such converters m a y be to dem onstrate through reliable testing that the conversion does not increase em issions, and to m a intain records docum enting test results. W e recom m e nd that converters with further questions about the Clean Air Act tamp ering prohibition contact EPA’s Office of Comp liance and Enforcem ent Assistance at: http://www.epa.gov/comp liance/basics/index.htm l

. Questions about conversion to specific fuel types and about fuel additives Fuel Additives 18.1 What is a fuel additive ? Ans

. 40 CFR Part 79.2 defines a fuel additive as “... any substance, other than one com posed solely of carbon and/or hydrogen that is intentionally added to a fuel...” Fuel additives to on-road gasoline and diesel fuels m u st be registered with the EPA. 18.2 Does adding a registered fuel additive to gasoline or diesel fuel require vehicle fuel conversion certification? Ans

. No, as long as 1) there are no changes to the vehicle' s engine or em ission system , 2) the additive is registered by EPA, and 3) you only add the quantity allowed under additive registration. 18.3 How do I register a fuel additive? Ans

. The registration requirem e nts depend on the specif i cs of the additive. Please see EPA Form 3520-13 for further inform ation. The form and additional inform ation are available at: http://www.epa.gov/otaq/regs/fuels/ffarsfrm s .htm

. Ethanol 19.1 What concerns does EPA have about aftermarket fuel conversions to E85? Ans

. OEM E85 flexible fuel vehicles (FFVs) fre quently use E85 fuel system components that differ in fuel delivery capacity, calibration, and m a terial composition from the fuel system components used in gasoline-only vehicles. In som e cases OEMs will use E85

-comp atible m a terials and design specifications in gasoline-only vehicles to avoid the extra costs associated with m a intaining two types of part inventories. If these OEM vehicle-specific design differences are not unde rstood and taken into consideration when converting a gasoline vehicle to E85, em ission and vehicle perform a nce problem s m a y result. 19.2 What components differ between OEM gasoline and E85 fueled vehicles? Ans

. The com ponent differences between OEM gasoline and E85 FFVs vary as a function of m a nufacturer, m odel year, and test group. Since the 1996 m odel year, all light-duty vehicles have been designed to accom m odate E10 – a m i xture of 10% denatured ethanol and 90% gasoline. However, unlike a vehicle designed to accom m odate E10 fuels, a vehicle designed to use E85 and interm ediate blends m a y require design changes in any or all of the m e tals, elastom e rs, and polym ers used in the fuel supply system from the f u el pipe inlet to the f u el injectors and inta ke m a nifold. Software calibration changes to the computer controlled fuel supply are also necessary to account for ethanol’s reduced volum etric energy content and unique stoich iom e try. Depending on the test group, fuel pumps, fuel injectors, and other key components in the fuel supply system m a y need to be changed to accom m odate the need for greater fuel delivery when using E85. 19.3 What are the considerations that go into designing E85 vehicles? Ans

. The challenge of properly designing E85 vehicl es or converting gasoline-fueled vehicles to E85 begins with understanding ethanol’s unique chem ical and physical properties relative to gasoline. The principal design considerations which m u st be properly m a naged include ethanol’s solvency of organic m a terials, the potential for galvanic corrosion of dissim ilar m e tals due to ethanol’s high electrical conductivity relative to gasoline, hydrocarbon perm eation, and seal failure if swelling of gaskets and O-rings occurs. 19.4 How do aftermarket fuel converters assure EPA that proper components are being used when converting a gasoline-fueled vehicle to E85? Ans

. On a test group specific basis there are four ways: 1) A converter could use the sam e OEM parts that the OEM used in the E85 FFV. 2) A converter could provide inform ation to dem onstrate that the fuel system part num bers for the OEM gasoline vehicle and a sim ilar vehicle which the OEM sells as an E85 FFV are identical. Identical part num bers dem onstrates that the gasoline-fueled vehicle was also designed with E85 com p atible parts. The com p arison between part num bers is best perform e d by com p aring dealer or OEM part num bers. 3) The fuel converter could provide whol e vehicle durability data using EPA standard durability testing protocols published in 40 CFR Part 86, Subpart S. For exam ple, having passing em ission data and knowing that the em ission control system , fuel system , and other powertrain com ponents did not experience failure of com ponents during thedurability aging would be adequate. 4) Proof of component durability m a y be accepted by EPA in the form of an analysis dem onstrating that the components in the gasoline-fuel system are E85 comp atible. Such a docum ent would need to com e from an OEM or a Tier 1 parts supplier, or the equivalent. Docum e ntation or analyses shoul d include references to recognized standard industry practices, for exam ple, reference to testing m e thods for m e tallic m a terials or polym ers described by the Society of Autom o tive Engineers. 19.5 Would EPA be satisfied if the converter extends the OEM’s base vehicle warranty to cover any concerns due to the installation of the conversion kit or the use of ethanol in the OEM gasoline-fueled vehicle? Ans

. No. Sim p ly extending the base-vehicle warranty does not com p letely address concerns about com ponent com p atibility. The concern with offering a lim ited warranty extension of tim e or m ileage to the OEM base vehicle warranty is that a com ponent problem m a y occur outside of the extended warranty lim its. 19.6 Does EPA share the same concerns it has regarding component compatibility in E85conversions with other types of fuel conversions, such as gasoline-to-CNG or gasolineto-LPG conversions? Ans

. Yes. Ensuring that fuel conversions use components that are durable for the full useful life of the vehicle is im portant for any alternative fuel because, unlike conventional large volum e OEMs, fuel converters are a type of sm all volum e m a nufacturer. As such, they have neither upf ront durability dem onstration requirem e nts nor in-use testing requirem e nts. EPA recom m e nds that converters resolve component comp atibility issues before conducting em ission or OBD testing. For example, if a conversion to CNG requires changes to the powertrain, such as inst alling a different type of intake or exhaust valve or valve seat, EPA would expect such m odifications to be part of the fuel conversion requirem e nts. 19.7 What emission tests does EPA recommend for certification of an E85 conversion? Ans

. The types of em ission tests EPA recom m e nds will depend on the conf iguration of the OEM vehicle and on the nature of m odifications involved in its conversion. If the converted vehicle operates as a flexible fuel vehicle (e.g. capable of operating on gasoline, E85, or any blend of the two), exhaust testing will be required on both E85 and on the original fuel. Testing for evaporative em issions could be required on E10, which is the worst-case fuel for evaporative em issions. If the converted vehicle operates only as a dedicated E85 vehicle testing would only be required on E85. At m i nim u m , recom m e nded testing would incl ude running FTP and Highway test cycles. However, as indicated above, the appropriate testing protocol will be technology specific and other exhaust as well as evaporative em issions cycles m i ght be recom m e nded. E85 converters should exam ine the OEM application and discuss with EPA any plannedm odifications to the OEM configuration befo re establishing testing plans. Decisions regarding what tests are required m u st be approved by EPA in advance. 19.8 Have there been any test procedure changes with respect to measuring NMOG (non

methane organic gas) exhaust or OMHCE (organi c material hydrocarbon equivalent) for the evaporative emission, running loss, or ORVR tests? Ans

. EPA regulations still ref e rence Calif ornia Air Resources Board test procedures f o r determ ining NMOG. EPA regulations allow the use of equivalent or better practices when supported by data and approved in advance by the EPA Adm i nistrator. Since the California NMOG procedures were proposed, OEMs have been granted approval to use a photo acoustic m u lti-gas analyzer called an Innova to m easure alcohols from an E85 vehicle. EPA uses the Innova m e thodology for m easuring alcohols at its Ann Arbor laboratory. Vegetable Oil 20.1 What are EPA’s policies with respect to diesel-to-vegetable oil conversions? Are they the same for virgin and waste vegetable oil? Ans

. EPA’s policy is the sam e for both virgin and waste vegetable oil. Like other fuel conversions, afterm arket system s that allow diesel vehicles to run on either virgin or waste vegetable oil fuel m u st be certified. This is necessary because diesel engines cannot operate on vegetable oil without signifi cant m odification to the fueling system

. As part of the certification application, EPA would expect the fuel converter to dem onstrate that the converted vehicle will m eet standards despite potential variation in vegetable oil fuel properties. 20.2 Can pure vegetable oil be “registered” as a diesel fuel with EPA? Ans. No. Vegetable oil is not classified as a type of diesel fuel. Vegetable oil and diesel fuel differ substantially in their chem ical and physical properties. It m a y be possible to register vegetable oil as a diesel f u el additive if the additive volum e is less than 5%. 20.3 Can I add a small amount of vegetable oil to my diesel fuel as a diesel fuel additive? Ans. Yes, assum i ng that you m eet the following two criteria: 1) There are no engine or em ission contro l system m odifications to your vehicle. 2) The vegetable oil is registered with EPA as a diesel f u el additive. EPA m a y register vegetable oil as a diesel fuel additive at a volum e of 5% or less. For inform ation about registering vegetable oil as a diesel f u el additive, please visit EPA’s f u el registration web site at http://epa.gov/otaq/regs/fuels/ffarsfrm s .htm

. Hydrogen 21.1 What are EPA’s policies with respect to converting OEM vehicles to 100% hydrogen?Ans

. Afterm arket conversions to hydrogen m u st certify under the appropriate standards and testing requirem e nts in 40 CFR Part 86. Howeve r, a few test procedures are not required since hydrogen-powered vehicles use a closed fueling system no evaporative em ission data subm issions are necessary. Additiona lly, because a pure hydrogen-powered vehicle has no com pounds in the fuel that contain carbon, there are no reporting requirem e nts for CO or NMOG. 21.2 What are EPA’s policies on adding hydrogen generator systems, such as hydrolysis systems (often referred to as HHO systems) to an OEM certified vehicle or engine? Ans

. EPA’s policy depends on the design of the HHO system and whether m odification to the OEM configuration is involved. Any HHO kit that requires engine or fueling system m odifications, or that includes com ponents that alter the em ission control system , would require EPA certification to avoid a potential violation of anti-tam p ering provisions of the Clean Air Act. In addition, if the system introduces into the engine any elem ents other than carbon and/or hydrogen, fuel additive registration would be required. See questions 18.1-18.3 for m o re inform ation. Most hydrogen generator system s produce less than 1% of total engine fueling requirem e nts and m a ny less than 0.1%. EPA does not view these system s as a type of fuel switching, but rather considers them a type of afterm arket device. EPA does not certify afterm arket devices. Manufacturers m a y voluntarily choose to have their afterm arket system evaluated under EPA’s “511 Program ,” which refers to EPA’s testing program of afterm arket devices, form erly conducted under authority of Section 511 of the Motor Vehicle Inform ation and Cost Savings Act. More inform ation on the 511 Program m a y be found at: http://www.epa.gov/otaq/consum er/reports.htm

. Electricity 22.1 What are EPA’s policies with respect to converting hybrid electric vehicles to plug-in hybrid electric vehicles? Ans

. EPA’s conversion policy applies to hybrid electri c-to-plug-in conversions. Certification is required to ensure that the converted plug-in hybrid will m eet ap p licab le em is s i o n s t an d a rd s and will rem a in clean and durable for its full useful life. This is necessary because any change to an OEM-certified configuration c ould affect the em ission control system and could be considered a tamp ering violation. In the case of an afterm arket plug-in hybrid conversion, for exam ple, it is possible that th e altered interaction between the internal com bustion engine and the battery electric syst em could cause m o re “cold starts” of the internal com bustion engine, thereby increasing em issions relative to the OEM vehicle.22.2 What are EPA’s policies with respect to converting vehicles to full battery electric? Ans

. Ve hi c l e conversions to full battery electric (no on-board source of com bustion em issions) do not require alternative fuel vehicle certifica tion as protection from a possible tam p ering violation.