Post date: Aug 23, 2010 6:44:52 AM
Conventional original equipment manufacturer (OEM) vehicles altered to operate on propane, natural gas, methane gas, ethanol, or electricity are classified as aftermarket alternative fuel vehicle (AFV) conversions. In the United States, all vehicle conversions (except pure battery electric vehicles) must meet current applicable U.S. Environmental Protection Agency (EPA) standards. EPA instituted these standards to assure unimpaired emission control of motor vehicles throughout their useful life. Vehicles operating in California must follow conversion rules issued by the California Air Resources Board (CARB).
In addition, vehicle conversions that require the addition of heavy battery systems or additional fuel tanks that may alter a vehicle's center of gravity, payload capacity, or handling characteristics may also need to be safety crash tested and certified to comply with Federal Motor Vehicle Safety Standards (FMVSS) and/or other National Highway Traffic Safety Administration (NHTSA) regulations.
This section provides information about conversions.
A converted vehicle is one that was originally designed to operate on gasoline or diesel and has been altered to run on an alternative fuel. Altering vehicles to run on compressed natural gas (CNG) or liquefied petroleum gas (LPG) are the two most common types of alternative fuel vehicle conversions.
OEM vehicles can be converted to "dedicated" AFVs, which means they operate exclusively on an alternative fuel such as propane or natural gas. They can also be converted to "bi-fuel" vehicles that have separate tanks for gasoline and the gaseous fuel. The desired fuel is usually accessed by flipping a switch to change tanks. Dual-fuel systems, such as flexible fuel vehicles, supply both fuels into the combustion chamber at the same time in various calibrated proportions.
For more information on AFV conversions, visit the following sections.
All vehicle conversions must be certified according to Mobile Source Enforcement Memorandum 1A (Memo 1A) issued in 1974; the Addendum to Memo 1A (PDF 32 KB), which was issued in 1997; and the Revision to the Addendum to Memo 1A (Revision), issued in 1998. Download Adobe Reader. The original purpose of Memo 1A was to enforce the tampering prohibitions under Section 203(a)(3) of the Clean Air Act with respect to maintenance and use of aftermarket parts. Its subsequent revisions outlined allowable procedures for converting vehicles to operate on alternative fuels while still complying with the Clean Air Act's tampering prohibitions and ensuring that emissions are not degraded through the conversion process.
In the mid 1990s, testing determined that some vehicles converted to operate on alternative fuels, specifically natural gas and propane, produced worse emissions than those of baseline gasoline vehicles. EPA then issued the Addendum to Memorandum 1A in September 1997, requiring more stringent emissions testing for AFV conversions.
EPA issues Certificates of Conformity that cover a "test group"—specific vehicle or engine models for certain model years that are modified to operate on an alternative fuel. Data for a test group retrofitted with a conversion company's alternative fuel system must be submitted to EPA for certification. Once the Certificate of Conformity is issued, vehicles in the test group may be converted by that conversion company to use that alternative fuel system.
Certificates of Conformity for "aftermarket" converters are signed by EPA and certify that the appropriate sections of the Code of Federal Regulations (40 CFR Parts 85 through 88) have been met. Certificates indicate:
The original test group of vehicles as determined and provided by the OEM.
The evaporative emissions family.
The state(s) in which the test group is certified (e.g. California vs. 50 state sales areas).
The "car line" (e.g., F-150, two-wheel drive, extended cab, 5.4-liter engine).
The model year of the vehicles included in the test group.
The emissions standards that are met.
An aftermarket conversion may only be performed on a vehicle if a Certificate of Conformity or CARB certification has been issued for that vehicle's test group.
For information on CARB procedures, visit the Certification of Alternative Fuel Retrofit Systems section of the CARB Web site.
The EPA refers to a vehicle converter as a "small volume manufacturer." The vehicle converter holds the Certificate of Conformity. An individual or entity wishing to convert a vehicle to operate on an alternative fuel must go through a company or organization associated with a certificate holder, and the work must be performed by a licensed technician associated with that company.
It is the responsibility of the certificate holder to ensure the equipment is properly installed and that it is safe, durable, and meets the emission standards of the original model year of the vehicle.
To qualify to perform aftermarket AFV conversions, potential certificate holders must complete an application and submit emissions test data to EPA for a test group of vehicles equipped with the retrofit system. Each year, certificate holders must file a new application to renew their certificates for test groups; they do not need to submit new test data in order to renew. For example, for the conversion of a model year (MY) 2003 vehicle, EPA can issue a MY 2007 certificate (enabling the certificate holder to convert that MY 2003 vehicle test group through the end of the 2007 calendar year).
The certificate holder could later apply for a current model year certificate when EPA begins issuing them (enabling the certificate holder to convert that model year vehicle test group through the end of the current calendar year). The certificates are valid through December 31 of each certification year. A manufacturer can reapply to convert prior year vehicles in subsequent years without conducting new emissions testing, as long as the conversion equipment and technologies are equivalent to what was first submitted.
If a Certificate of Conformity has not been issued for your vehicle, a certificate holder may consider applying for a Certificate of Conformity for that vehicle. The certificate holder may also provide an estimate on how much it would cost to convert your vehicle. See the Federal and State Laws and Incentives section to find incentives and other programs that could help offset conversion costs. Select Conversion Companies in the related links search to find companies that perform conversions.
Beginning with MY 2005 light-duty vehicles (MY 2007 for heavy-duty vehicles between 8,500 lb. and 14,000 lb. gross vehicle weight rating), all conversions must be onboard diagnostic system (OBD II) compliant when operating on the alternative fuels. No false OBD codes or false malfunction indicator light (MIL) illumination should occur. For dual-fuel vehicles, the OBD II system must not be affected by the conversion when operating the vehicle on gasoline. Testing for compliance should be conducted by inducing failures to the emission system.
EPA-assigned deterioration factors (DFs) were updated on May 26, 2005, and alternative fuel converters must use these DFs for emissions measurements on vehicles using alternative fuels. These apply to dedicated AFVs and dual-fuel vehicles when operating on alternative fuels.