Using LP Gas as an Automotive Fuel

LP Gas Fueled Vehicle

LP Gas as an Automotive Fuel

For people that are serious about limiting the damage their cars cause the environment while driving to work every day there are many cleaner options available- options that include hybrid cars, several types of alternatively-fueled vehicles, alternative and exotic fuels, pure electric cars, or cars that – depending on driving conditions – can run on several types of fuel at different times.

One such option is to convert an existing car to run on LP gas. Liquefied petroleum (LP) gas has been around since 1912, and has been used as an automotive fuel for much of the time since then. The benefits of propane as a fuel are considerable, and undisputed. For instance, its octane rating is close to that of gasoline and diesel, while at the same time burning significantly cleaner than either gasoline or diesel.

Advantages of LP Gas as a Fuel

Figures released by the World Liquefied Petroleum Gas Association (WLPGA), reveal that worldwide, nearly ten million cars run on LP gas today, and that the effects of the reduced emissions on the environment that this fuel offers is measurable. Some emission measurements as compared to gasoline are listed below:

  • 50% less carbon monoxide,
  • 40% fewer hydrocarbons,
  • 35% less nitrogen oxides (NOX), which translates into 50% less damage to the ozone layer.

Moreover, with various tax incentives and other factors such as the price at the pump, LP gas is a more cost effective fuel than either gasoline or diesel. But that is not all, many owners of older cars report that their vehicles run more efficiently, and cost less to maintain than when they used gasoline, but as with everything in life, LP gas has serious drawbacks and disadvantages as well.

LP Gas Tanks

Disadvantages of LP Gas as Fuel

All new cars are nothing if not computers on wheels, and to make them work satisfactorily on pump gasoline and diesel, their electronic control systems have been developed and calibrated to extract as much energy from regular fuels as possible. While some manufacturers such as Ford, General Motors, and Daimler-Chrysler have developed engine and fuel management systems that do the same thing with LP gas, there are not many models to choose from, which robs LP gas of much of its allure as a viable alternative fuel.

However,  for car owners who do not want to, or cannot afford to buy a new vehicle that is optimized for LP gas, and which are often not available on the dealership floor and must be ordered specially, there is nothing much he can do to convert his late model car to run on LP gas.

Of course, those are the obvious drawbacks, but on a more practical level, there are several more, but less apparent problems with LP gas as an automotive fuel- some of which are listed below:

Fuel vs. Engine Management Systems

Electronic fuel management systems are not intuitive or adaptive. They cannot determine the calorific value, or energy content of a fuel and adapt accordingly to deliver the same, or  close-to-the-same performance if say, it was calibrated to manage an engine meant to run on gasoline.

This translates into poor performance, and possibly a condition in which the car becomes undriveable since engine power at specific engine speeds is only one of  the determining factors that control modern automatic transmissions. This is of course a gross over simplification of how modern cars are controlled, but the fact remains that control systems cannot compensate for the wrong fuel, since manufacturers of control systems often encrypt their software to make it almost impossible to alter settings and operating parameters.

Cheap LP Gas Conversions Do Not Exist

While there are several companies that have developed software to convert engine management systems to control alternative fuels, these systems are almost exclusively designed for ethanol systems, and not LP gas. Moreover, these conversion kits are also almost exclusively designed for mega-expensive supercars, and come with price tags that are higher than what you paid for your late model family sedan.

One way past the insurmountable problem of conversion costs, is to convert an older car, but even then, the cost of conversion could exceed the value of the car because of the variables involved. As a general rule of thumb, it is very much easier to get a conversion wrong than it is to get it right, and even if you do get it right after several months of trying, it could be several years before the conversion has paid for itself in terms of lower fuel and running costs.

Limited Range

It is disingenuous to judge an alternative fuel on the basis of its heat energy per given volume alone.  While the difference to that of gasoline may not appear to be a problem on paper, it is an indisputable fact that the calorific value of gasoline is higher than almost any other alternative fuel except for hydrogen. While heat energy is measured in BTU’s (British Thermal Units), the calorific value (Joules) of a fuel refers to how much work can be extracted from a given volume of fuel. Thus, there is more usable energy in a gallon of gasoline, than there is in a gallon of liquefied LP gas, which translates into fewer miles per gallon if the vehicle runs on LP gas alone.

No Standardized Nozzles

Even though there are 3000 or so LP gas filling station across the US, there are no nozzles that fit every filler cap. However, this problem is not confined to LP gas cars- even owners of rechargeable electric cars may find that the adapters in the next state do not fit his say, Tesla, or Chevy Spark.

The problem of incompatible nozzles, adapters and connectors is arguably the biggest single stumbling block that is preventing the implementation of alternative fuels in any meaningful way.

What Tax breaks?

While the US Government is preaching about the advantages of alternative fuels, and is even offering to pay for half of the conversion to run alternative fuels, what it practices is quite the opposite. On the one hand the Government promises to help pay for the cost of conversion in the form of a tax break, but on the other hand the law says something quite different; therefore to make it abundantly clear that the Government is speaking with a forked tongue, below is an extract from the actual AFV(Alternative Fuel Vehicle) Conversion Tax Credit released by the Department of Energy that promises to pay for the conversion- but does not:

Alternative Fuel Vehicle (AFV) Conversion Tax Credit:

Businesses or individuals are eligible for an income tax credit of up to 50% of the equipment and labor costs for converting vehicles to operate using alternative fuels. Qualified alternative fuels are compressed and liquefied natural gas, liquefied petroleum gas (propane), hydrogen, electricity, and fuels containing at least 85% ethanol, methanol, ether, or another alcohol. The maximum credit is $500 for the conversion of vehicles with a gross vehicle weight rating (GVWR) of 10,000 pounds (lbs) or less, and $1,000 for vehicles with a GVWR of more than 10,000 lbs. The credit is only available during the year that the business or entity converts the vehicle. An alternative fuel seller may not receive a credit for converting its own vehicles to operate on the alternative fuel they sell. (Reference: Montana Code Annotated 15-30-2320)

The Future of LP Gas as a Fuel

From the above tax credit is should be abundantly clear that unless the Government gets real about making it possible for car owners to convert to alternative fuels, all such fuels will remain nothing but DIY projects for an exceedingly small percentage of the motoring public.

Without robust and continued support from national Governments for alternative fuels, LP gas, like hydrogen and others, will never make a meaningful impact on the fossil fuel dependence of industrialized nations the world over.

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