Hybrid Benefits

Fuel Efficiency

With respect to fuel economy, ISE's diesel hybrid system has demonstrated significant advantages over conventional buses and competing hybrids. The first buses using ISE's diesel hybrid system, operated by New Jersey Transit since mid-2003, have averaged higher than 5.5 miles per gallon, covering approximately 80,000 miles of total operation. These buses have also been shown to be highly reliable, with only one in-service drive system failure over this period.

The ISE fuel economy is a 20% improvement over the standard diesel buses NJT is operating out of the same garage - which are the most fuel-efficient buses in NJT's conventional fleet. ISE believes its diesel hybrid system will have an even greater advantage over buses that operate on more urban routes, which typically get only 2.5 to 3.5 mpg (versus the 4.7 mpg NJT gets with the conventional diesel buses used in this comparison). ISE believes its diesel hybrids will still get 5 mpg or more on urban routes, which would represent a fuel economy improvement of at least 30-50% over standard diesel buses on these routes.

ISE’s fuel efficiency results also compare favorably with the fuel savings offered by competing hybrid systems. In December 2004, the New York Times reported that, in the estimation of transit managers, the General Motors Allison hybrid drive system was resulting in “savings around the country [that] appear to be in the range of 10 percent to 20 percent.” The Times article also reported that “Some bus agencies report greater fuel savings using a "series" hybrid, in which the engine is connected only to an electric generator, with all the power to the wheels coming from an electric motor.” The ISE hybrid system is this type of series system.

The ISE improvements in fuel economy are due to several advanced features of the ISE series hybrid system, such as all-electric operating capability, electrically-driven accessories, engine idle-stop capability, and use of advanced batteries and ultracapacitors. In fact, ISE's competitive advantage in the hybrid industry is widening because of ISE's ability to adapt its system to new, performance-enhancing technologies more rapidly than its competitors.

ISE introduced the first hybrid transit buses using nickel sodium chloride batteries and the first buses to use Maxwell Technologies' latest generation ultracapacitor. The nickel sodium chloride batteries store more energy than competing battery chemistries and maximize all-electric operating range and grid charging opportunities for customers who desire these features.

Within the last year ISE also introduced state-of-the-art Cobasys nickel-metal-hydride batteries as another energy storage choice.

Ultracapacitors store and release energy much more efficiently than batteries and are ideal for boosting acceleration and recapturing braking energy with minimum onboard energy storage weight. Ultracapacitors are also expected to last five to ten years in vehicle applications - significantly longer than most battery technologies.