"Two is better than one"

Many ideas and technologies that emerge in the alternative fuels industry never evolve into working products. The main goal in developing these ideas is to create technology that reduces the use of gasoline or diesel fuels. Most consumers are aware of the fact that currently no one technology will replace the use of gasoline and diesel. The industry continues to push the envelope to extend the amount of remaining gasoline and diesel fuel available, and one such technology may do just that. Using existing diesel engines and incorporating compressed natural gas (CNG) or liquefied petroleum gas (LPG), it operates on what is known as dual fuel mode. To better understand what dual fuel mode is, we will take a look at some terminology and explain what makes this technology work.

Diesel engines operate on compression ignition where the heat of compression ignites the diesel fuel. Gasoline vehicles operate on spark ignition. Typically in the past when we think of a diesel engine operating on CNG or LPG, the engine needs to undergo major modifications. The reason for these modifications is that both CNG and LPG will not ignite from compression ignition. The existing diesel engine needs to be adapted to spark ignition, and this means the engine will only operate on that designated alternative fuel (these are referred to as dedicated engines). Recent technology has allowed us to achieve the best of both worlds.

The industry now offers conversion systems that will supply both conventional diesel and either CNG or LPG into the combustion chamber. The idea is simple but the technology that makes these systems operate is complex. The dual fuel mode offers a way to supply a reduced amount of diesel fuel and a greater amount of CNG or LPG with little modification. These engines remain as compression ignition by igniting the small amount of diesel fuel that in turn ignites the gaseous fuel simultaneously.

For more information, please refer to the list above to direct you to the Web sites of some of the companies offering conversion systems.

The use of the dual fuel system has several advantages as it reduces the amount of diesel fuel used, greatly reduces exhaust emissions, provides the same horse power, and reduces operating costs. This is achieved by a combination of 50-70 percent gaseous fuel to diesel fuel mixture. The reduction in exhaust emissions is approximately 50 percent and better. These numbers vary due to the different conversion systems available and the engine that has been converted.