TransTeq provided the 36 CNG-electric series-hybrids operated as shuttle buses by Denver RTD.
GCC Illustration
General Motors has begun to premier the Saturn VUE Green” Line. One of the features of such dual mode hybrids can be one single electrical device, which UQM Technologies refers to as an SMG, for three separate functions: 1) Starter, 2) traction Motor, and 3) Generator.
Speaking of UQM, Green Car Congress tells us that Denver Regional Transportation District is making use of other UQM technology in a retrofit of ten CNG-electric series-hybrids. With natural gas prices tripling or, in some cases, quadrupling it makes sense to increase the efficiency of the mall shuttle buses that provide “a free ride for passengers across the 1.3-mile long mall. The shuttle buses connect “with the light rail, express and regional Denver RTD services.”
The retrofitting of each 45-foot bus will include a 35 kW generator and two UQM power electronic motor controllers that feature regenerative braking. Adding “regen” decreases the need for the “genset” to produce electricity for recharging the banks of batteries that power the shuttle. The generator set consists of a CNG-fueled 2.5-liter Ford industrial engine and UQM generator. With rising gas prices, it is commendable of this premier model for urban transit in the United States to focus on improvements to the electric drive since the genset already operates in an optimal range, i.e., 2,200 rpm.
RTD previously had announced that it had begun to upgrade the energy storage from lead-acid to Cobasys NiMH battery packs.
The NiMHax 288-120 is a two-system parallel package (two NiMHax 288-60 systems) that utilizes Cobasys high voltage Series 1000 NiMH battery modules to provide a nominal voltage of 288 volts and 120 kW of power… A complete battery system, the NiMHax 288-120 includes: the battery management system, thermal management system, and CAN communications.
So, EV advocates, maybe, all the long, loud, emotional utterances about restriction of large-format NiMH systems by the “oilies” was not in vain, eh?
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\”The stop-start nature of urban driving,\” writes Michael Kanellos, has meant that buses have become \”a test platform for ideas for energy-efficient vehicles.\” He implies, by reference to another CNET news article, \”Powering a New Generation of Cars\” that as more and more cities have begun to buy serial hybrid buses, we may see Homogeneous Charge Compression Ignition generator sets replacing those that use spark (gasoline / petrol) or compression (diesel) ignition. \”Karina Morley, director of powertrain control electronics at automotive-systems supplier Visteon, says that the gas burning engine\’s days are numbered.\”