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Open Access Publications from the University of California

Evaluation of Greenhouse Gas and Criteria Emissions From Conventional and Hybrid Off-Road Equipment

  • Author(s): Cao, Tanfeng
  • Advisor(s): Cocker, David R
  • et al.

Hybrid technologies on both on-road and off-road applications offer potential in reducing both GHG emissions and criteria emissions by using sophisticated vehicle designs with multiple power sources. Environmental regulations today are starting to shift from criteria emissions to include GHG emissions. However, criteria emissions are still significant contributors to local air pollution in many populous areas throughout the United States. Many different designs for hybrid applications have emerged within the last decade, but reliable studies on their performance, efficiency, and emissions are limited for on-road vehicles and non-existent for off-road hybrid equipment. Unexpectedly, some on-road hybrid vehicles studies have shown a considerable increase in criteria emissions while achieving the desired fuel economy benefits. The research presented in this dissertation evaluates the criteria and GHG emissions benefits of hybrid technologies in off-road bulldozers and excavators. Measurements of power duty cycle and emissions hybrid within this dissertation greatly improve our understanding of the emission inventories of off-road engines, and also offer a new approach on evaluating real world benefits of hybrid off-road engines. Additionally, this dissertation investigates the latest portable emissions measurement equipment (PEMS) technologies which are critical for determining in-use emissions. Finally, in-use emissions rates from a variety of conventional off-road equipment are evaluated for off-road equipment such as backhoe loaders, dozers, excavators, motor graders, wheel tractor-scrapers, and wheel loaders.

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