Nick Echter Defense
Tuesday, May 29, 2012, 10:30 AM
Lory Student Center, Room 214

Nicholas Echter M.S. Final Exam and Defense 10:30 a.m., Tuesday, May 29th, 2012 Room 214, Lory Student Center.

Advisor: Thomas Bradley Committee: Guy Babbitt, Peter Young.

Parallel Hydraulic Pressure Assist/Work Circuit Hybrids for Automated Side Loader Refuse Vehicles Abstract Work circuit hybrids show potential to improve the fuel economy of refuse vehicles. Prior to this study, the design of a work circuit hybrid had not been explored in detail. The following questions are answered; what are the fuel economy and cost characteristics of an optimized work circuit hybrid, and can an advanced hydraulic work circuit design justify further development towards productization? The feasibility of work circuit hybrids on refuse vehicles is explored at a high level. Methods were developed to characterize the components of these hybrids and the potential hybrid configurations. Data was collected on two automated side loader, 28 cubic yard (21.4 m3), McNeilus Street Force MA refuse vehicles that operate on residential routes throughout Denver’s surrounding areas. From this data, the drive cycle and hydraulic duty cycle was determined. It was shown that the vehicle spends 84.0% of the day below 30 kph and 83.7% of fuel consumption occurs at idle; providing potential for hybridization to improve operation. A reverse facing model was laid out for the stock vehicle and for the work circuit hybrid. Collected real-world data was used to validate the model of the stock vehicle. It was reported that the measured work circuit energy on these Denver based refuse vehicles only amounts to 16% of the available regenerative braking energy. Analysis of system operation shows that an automated side loader arm circuit does not require enough energy to utilize the full potential of the work circuit hybridization. To complete the study, subsystem components were optimized using a Simulated Annealing algorithm. The system was optimized for fuel consumption and total cost. Results show the benefit of this type of hybrid is limited to the energy required by the work circuit. However, this research shows that combining work circuit hybrids with idle stop technology increases the fuel savings from 2.3% to 21.6%. The optimization showed that low cost, small components lead to a payback period as low as 6 month when combining work circuit and idle stop technologies. There are still some major challenges to overcome before this technology can truly be expected to become economically feasible. However, if idle stop is used in conjunction with work circuit hybrids, it is the conclusion of this study that work circuit hybrids do offer substantial increases in fuel economy and it is therefore recommended for further development.

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Event Contact: Zulema Sierra can be reached at (970) 491-6036

Sponsored by the Department of Mechanical Engineering.