Carlab-CNG-gasoline-hybrid-conversionsThe rising cost of gasoline and diesel fuel is prompting many consumers, both fleet owners and individuals, to investigate options to retrofit or convert their car(s) or truck(s) to run either (1) solely on natural gas, which is referred to as “dedicated” or (2) to run on gasoline or natural gas, which the federal government refers to as “dual-fuel” although the accepted nomenclature for such vehicles is “bi-fuel.” Converting a new vehicle provides the greatest opportunity to save fuel cost and, thereby, pay back the conversion cost and generate life-cycle savings.


Installing EPA Certified aftermarket parts does not affect the original equipment manufacturer’s warranty. This is the case with the installation of aftermarket conversion systems. EPA has stated that the “vehicle’s original manufacturer remains liable for warranty of any systems which retain their original purpose following conversion, except in cases where the failure of such a system is determined to be caused by the conversion.” In addition, EPA guidance states that “the conversion system manufacturers would be responsible for the emissions warranty for any parts or systems added by the conversion.”


The EPA has the authority under the Clean Air Act to regulate vehicle emissions for all new motor vehicles. Moreover, it also has authority to regulate modifications of in-use vehicles if the modification tampers with the vehicles emission control systems.


To obtain an EPA Certificate, the retrofit system manufacturer must submit substantial emissions performance data and related documentation for each test group or engine family to be reviewed.


This testing ensures that the retrofitted vehicle meets the same stringent emissions requirements as original equipment vehicles. The testing also ensures that the retrofit system works seamlessly with the on-board diagnostics system to warn the driver when emissions are outside of approved parameters and to log those anomalies in the computer memory for downloading by the automotive service technician. This is an important criterion, since systems that do not do this will fail state and local emissions tests.


The Environmental Protection Agency (EPA) requires the manufacturers of aftermarket systems to certify that their conversion systems meet emissions and onboard vehicle diagnostics interface requirements. EPA can levy substantial fines for violating this requirement, since it is against the law to tamper with emissions systems on vehicles if the result is greater emissions.


The installer is responsible for obtaining the fuel storage system components (cylinders, high-pressure tubing, press release device, brackets, and protective plates) and for installing them in accordance with the National Fire Protection Association’s Vehicular Fuel System Code (NFPA 52). These safety-oriented issues are the domain of the local fire marshal, and most jurisdictions have adopted NFPA 52 as their standard for proper installation of natural gas vehicle systems. Consumers should ask installers to confirm that the installation meets NFPA 52 requirements.