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7. Installation of Auxiliary Power Units for long-haul trucking

Installation of Auxiliary Power Units for long-haul trucking

The analysis and conclusions contained in this case study are those of the authors alone and do not necessarily represent the point of view of the Government of Canada.

Organization
Saskatoon Diesel Services Limited, Diesel Services Group

Major Findings
Using an auxiliary power unit reduced greenhouse gas emissions by 9.190 tonnes in the five month test period.

Project Timeline
September 2006 to July 2007

Please note that some figures such as cost savings on fuel are based on data from the period that this project took place.

Introduction

The rising cost of fuel, greenhouse gas (GHG) regulations, and growing environmental concerns has spurred the creation and adoption of new technologies in the freight transportation sector. With funding from Transport Canada’s Freight Sustainability Demonstration Program, Saskatoon Diesel Services Ltd. (DSG) undertook a project to demonstrate the emissions-reducing advantages of auxiliary power units (APU).

An APU is a generator that provides heating and cooling for truck cabs, as well as serving as an engine block heater. APUs help to save fuel by reducing or eliminating engine idling while at driver rest stops, or while loading or unloading the vehicle. It also helps to extend the life of engines since they spend less time running. All freight transport modes are starting to employ APUs to preserve the life of the main engines, as well as cut back on fuel consumption and emissions.

While the oil industry has not traditionally used APUs due to the complex safety regulations governing the industry, this technology is slowly making inroads as the need for emissions reduction rises.

Project Description

The CANtemp APUs were designed for the Canadian climate with the expectation that they would be more reliable and user-friendly. The long-haul test vehicles were all Peterbilt trucks that traveled on similar routes. DSG proposed to test the APUs on long-haul trucks, and trucks in the oilfield industry. Another APU was to be tested for long-term reliability at an independent test center.

Twelve long-haul trucks would be monitored, with four using the APUs (experimental group), four using other current APU technology, and four with no anti-idling technology (control group).

Project Objectives

One objective of this project was to demonstrate that DSG’s own APU anti-idling technology is more efficient than other APUs, particularly in the Canadian north. Expectations included reduced fuel consumption and idling time, resulting in reduced emissions. The second objective was to increase the use of this efficient and reliable technology.

Project Methodology

Baseline data was collected from the fleet before the project began in the fall of 2006. The project engineer collected data from both the control group and the experimental group using Engine Control Modules (ECM) reader equipment, APU hour-meters, driver’s logs and monthly surveys. This data would include lifetime fuel economy and idling time. Data from both groups were measured against the baseline data collected before the project began.

GHG reductions were calculated based on the Commercial Transport Energy Efficiency Rebate: the reduction of one litre of diesel fuel results in 0.0028 fewer tonnes of GHG emissions.

Results

This project experienced a number of problems, so the scope of the results was somewhat reduced. The APUs were designed, built and bench-tested, but installation was delayed because the APU generator belt drives kept snapping under test conditions. This delay meant that no hot weather testing was performed. Four APUs were installed on long-haul trucks in the fall of 2006, and two oil field units were installed in February 2007.

Major engine failure occurred on two of the long-haul units, and it was determined that despite modifications, the belt drive continued to be the cause. One of the failed engines was sent to Mitsubishi for testing, but no substantial analysis was done before the end of the project because of human resource issues. In light of this lack of analysis, the units were pulled from the oil fields in case another major engine failure occurred.

More data collection problems occurred with the departure of an engineer playing a major role in the project. Data from one long-haul unit was saved, and backed up by operator logbooks and management records.

Lastly, monitoring was hampered because truck operators did not keep consistent records about APU use.

The end result was that proper field analysis was done on one long-haul unit and bench testing was done at the DSG facility instead of an independent facility.

Accurate test data was recorded for five winter months. The chart shows that the use of the APU in the experimental unit reduced GHG output by 9.190 tonnes compared to the fleet average and reduced GHG output by 7.565 tonnes compared to the control unit.

Unit	Idling Hours	Fuel Used (litres)	GHGs Produced (tonnes)
Fleet Average	1296	5965.85	12.763
Control Unit	1291	5167.54	11.138
Experimental Unit	339	1276.14	3.573

Conclusion

When the final report for this project was submitted in May 2007, DSG felt there was still some resistance to APUs in the trucking industry. The reliability of APUs is important to drivers who depend on them to allow their vehicles to start in cold weather and to provide cab cooling or warmth at rest stops. They also felt that their project demonstrated that with proper training and technical support, drivers learn quickly to appreciate the benefits of an APU. Since 2007, the use of APUS in the trucking industry has increased substantially.

Regardless of the inconsistent use of the APUs due to the various problems listed in the 'Results' section of this study, the test proved that reduced idling significantly reduces the amount of diesel fuel consumed, and consequently the amount of GHGs produced. The data collected from one unit showed reductions of 67% to 72% in GHG emissions with even "somewhat regular" use of the APU.

Additional Information

• Diesel Services Group
• US Environmental Protection Agency

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Date modified:

2012-02-09

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