Hybrid Fuel Systems is a small company with a product by the same name that converts medium- and heavy-duty diesel engines to a “dual fuel” mode that replaces about 80% of the diesel fuel with Compressed Natural Gas (CNG) or Liquefied Natural Gas (LNG).
HFS systems start the engine with diesel fuel and then inject an increasing amount of natural gas, cutting back on the diesel, as the engine speed and load increases. Engine modifications are not required, and the company claims that vehicles retain the diesel engine qualities of performance, torque, power, and efficiency. When operating with natural gas, Hybrid’s system reduces NOx emissions by at least 30% and PM emissions by 80–90%.
The system consists of a set of parts that can be installed on most medium- and heavy-duty diesel engines within a day by a trained technician. Components include:
The ECU programmed to meter a precise mixture of natural gas and diesel in response to engine speed, load, temperature and other operating conditions
A gas regulation system that maintains a smooth fuel supply under all conditions
A gas injection system that allows precise metering under rapidly changing engine conditions
Sensors, wiring harnesses, and all other parts
The cost of the conversion kits range from $3,500–$4,500, not including the natural gas tanks and lines. Still, it sounds like a pretty good deal dollar-wise.
Hybrid Fuel Systems has installed 1,400 kits to date.