LPG Conversions
LPG Is a Good Fuel for Fleet Service.
Many propane vehicles are converted gasoline vehicles. Conversion kits offered include a regulator / vaporizer that changes liquid propane to a gaseous form and an air / fuel mixer that meters and mixes the fuel with filtered intake air before the mixture is drawn into the engine’s combustion chambers. Also included in conversion kits is closed-loop feedback circuitry that continually monitors the oxygen content of the exhaust and adjusts the air / fuel ratio as necessary. This device communicates with the vehicle’s onboard computer to keep the engine running at optimum efficiency.
LPG vehicles additionally require a special fuel tank that is strong enough to withstand the LPG storage pressure of about 130 pounds per square inch. The gaseous nature of the fuel / air mixture in an LPG vehicle’s combustion chambers eliminates the cold-start problems associated with liquid fuels. In contrast to gasoline engines, which produce high emission levels while running cold, LPG engine emissions remain similar whether the engine is cold or hot.
Also, because LPG enters an engine’s combustion chambers as a vapor, it does not strip oil from cylinder walls or dilute the oil when the engine is cold. This helps LPG powered engines to have a longer service life and reduced maintenance costs. Also helping in this regard is the fuel’s high hydrogen-to-carbonratio (C3H8), which enables propane powered vehicles to have less carbon build-up than gasoline and diesel powered vehicles.
LPG delivers roughly the same power, acceleration, and cruising speed characteristics as gasoline. It does yield a somewhat reduced driving range, however, because it contains only about 70-75% of the energy content of gasoline. Its high octane rating (around 105) means, though, that an LPG engine’s power output and fuel efficiency can be increased beyond what would be possible with a gasoline engine without causing destructive “knocking.” Such fine-tuning can help compensate for the fuel’s lower energy density.
Fleet owners find that propane costs are typically 5% to 30% less than those of gasoline. The cost of constructing an LPG fueling station is also similar to that of a comparably sized gasoline dispensing system. Fleet owners not wishing to establish
fueling stations of their own may contact us for options. There are over 3,000 publicly accessible fueling stations nationwide.
How Safe Is LPG? Propane is an odorless, nonpoisonous gas that has the lowest flammability range of all alternative fuels. High concentrations of propane can displace oxygen in the air causing the potential for asphyxiation. This problem is mitigated by the presence of ethyl mercaptan, which is an odorant that is added to warn of the presence of gas. While LPG itself does not irritate the skin, the liquefied
gas becomes very cold upon escaping from a high-pressure tank, and may therefore cause frostbite, should it contact unprotected skin. As with gasoline, LPG can form
explosive mixtures with air. Since the gas is slightly heavier than air, it may form a continuous stream that stretches a considerable distance from a leak or open container, which may lead to a flashback explosion upon contacting a source of ignition.
Clean Air Act
SEC. 247. VEHICLE CONVERSIONS.
(a) Conversion of Existing and New Conventional Vehicles to Clean-Fuel Vehicles.- The requirements of section 246 may be met through the conversion of existing or new gasoline or diesel-powered vehicles to clean-fuel vehicles which comply with the applicable requirements of that section. For purposes of such provisions the conversion of a vehicle to clean fuel vehicle shall be treated as the purchase of a clean fuel vehicle. Nothing in this part shall be construed to provide that any covered fleetoperator subject to fleet vehicle purchase requirements undersection 246 shall be required to convert existing or new gasoline or diesel-powered vehicles to clean-fuel vehicles or to purchase converted vehicles.
(b) Regulations.- The Administrator shall, within 24 months after the enactment of the Clean Air Act Amendments of 1990, consistent with the requirements of this title applicable to new vehicles, promulgate regulations governing conversions of conventional vehicles to clean-fuel vehicles. Such regulations shall establish criteria for such conversions which will ensure that a converted vehicle will comply with the standards applicable under this part to clean-fuel vehicles. Such regulations shall provide for the application to such conversions of the same provisions of this title (including provisions relating to administration enforcement) as are applicable to
standards under section 242, 243, 244, and 245, except that in the case of conversions the Administrator may modify the applicable regulations implementing such provisions as the Administrator deems necessary to implement this part.
(c) Enforcement.- Any person who converts conventional vehicles to clean fuel vehicles pursuant to subsection (b), shall be considered a manufacturer for purposes of sections 206 and 207 and related enforcement provisions. Nothing in the preceding
sentence shall require a person who performs such conversions to warrant any part or operation of a vehicle other than as required under this part. Nothing in this paragraph shall limit the applicability of any other warranty to unrelated parts or operations.
(d) Tampering.- The conversion from a vehicle capable of operating on gasoline or diesel fuel only to a clean-fuel vehicle shall not be considered a violation of section 203(a)(3) if such conversion complies with the regulations promulgated under subsection (b).
(e) Safety.- The Secretary of Transportation shall, if necessary, promulgate rules under applicable motor vehicle laws regarding the safety of vehicles converted from existing and new vehicles to clean-fuel vehicles.
[42 U.S.C. 7587]
