Retrofits Convert Gas Vehicles into Hybrids

One initiative at Glenn Research Center, the Hybrid Power Management (HPM) program, focused on joining new and mature technologies for optimal power systems applications in space and on Earth, with the goal not only to develop ultra-efficient space power systems, but also to advance HPM to address global energy issues.

Unlike batteries that store and discharge energy through chemical reactions, supercapacitors store energy electrostatically. In this way, supercapacitors charge and release energy more quickly than a battery, and unlike a battery, can tolerate up to 1 million charge and discharge cycles without wearing out. Though there were certain disadvantages compared to batteries, such as low energy storage, supercapacitors presented an interesting candidate to couple with batteries or other power sources in space applications or in hybrid electric land vehicles.

To help test the effectiveness of supercapacitors for power systems, NASA formed a unique partnership that involved a dragster named “Bad Amplitude” that was battery-powered. Capable of achieving a speed of 127 miles per hour in a quarter mile, the dragster was a testbed for the supercapacitors NASA was studying. Glenn partnered with the dragster’s developer, NetGain Technologies LLC of Lockport, IL. The partnership also focused on the development of a retrofit system for converting rear-wheel-drive vehicles into gas/electric hybrids, installing an electric assist motor, and using supercapacitors instead of batteries.

While the supercapacitors ultimately did not suit the dragster or the retrofit system, NetGain had provided NASA with significant data on supercapacitor use, and had proven the viability of a hybrid retrofit system (HRS) using batteries. The company continued developing the HRS, including methods for coordinating the operation of electric motors and internal combustion engines. This NASA-derived work has now led not only to commercial HRS technology, but also to the world’s most popular line of motors for electric vehicles.

NetGain’s Engine/Motor Interface System (EMIS) employs an electric motor inserted into the drive train of a standard gas-powered vehicle to supply electrical assist power to the internal combustion engine. Through monitoring multiple engine performance parameters, EMIS establishes the appropriate amounts of assist power to enhance the vehicle’s fuel economy. The system operates in the background, requiring no driver intervention or changes to typical driving habits.

Not only has NetGain pioneered a commercial HRS based on its work with NASA, but it has also innovated the related electric motor technology. The company made a series of positive engineering changes to electric motors. NetGain’s sales of these advanced motors quadrupled from 2004 to 2005, and nearly tripled again in 2006. In 2007, a sister company, NetGain Motors Inc., was formed to focus on manufacturing and marketing the entire line of electric motors.

The combination of the electric motors with the EMIS system has provided an affordable hybrid vehicle option. While the benefits to fuel economy change depending on the vehicle, motor and battery size, and driving conditions, NetGain’s results from its delivery truck testbed indicated fuel savings of 15–26 percent. The company believes the short-distance, multiple-stop delivery truck market represents an ultimate application for the HRS technology.

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