CNGVA Study Finds Issues Similar to Those of Diesels
Common sense precautions make for normal operations using CNG even in the severe cold winter weather of Canada, finds a new study being circulated by CNGVA, the Canadian Natural Gas Vehicle Alliance.
Evaluation of Winter Performance of CNG Refuse Trucks was prepared for Transport Canada by Dr. Alex Lawson of Ontario’s Alex Lawson Associates and Neil Cooke – transportation, math and science chairman at Red River College in Manitoba.
“By far the most common issues which affect satisfactory performance of CNG vehicles in cold climates are fuel quality and contaminants,” states a report summary.
EBI and Emterra NGVs
The authors studied a fleet of 18 CNG-fueled Peterbilt refuse trucks operated by EBI, which operates a growing fleet of compressed natural gas vehicles and is establishing a public access CNG fueling network in greater Montreal (F&F, November 5). They also drew on recent cold weather experiences involving 58 CNG-fueled Crane Carrier refuse trucks operated by Emterra Environmental in Winnipeg (F&F, June 18, 2012).
Simply put, the most common problem is water content in the fuel: “The colder the ambient temperature becomes, the drier the natural gas has to be,” the report states. “It is therefore critical to ensure that a dryer is included in the CNG refueling station and that the dryer is properly maintained.”
Contamination from compressor oil carry-over can also be an issue, the authors note.
‘Normal Operations Will Be Experienced’
“As occurs with diesel engines, as the operating climate becomes colder, an increasing number of winter aids, vehicle modifications, vehicle preparation, operating practices, and maintenance procedures are typically required to ensure satisfactory vehicle operation,” the report notes.
“It can be concluded that if the vehicle winter aids are used that are appropriate for the vehicle at its designed ambient operating temperatures and if the natural gas fuel is adequately dry and meets requirements related to heavy hydrocarbons and compressor oil carry over, then normal operations will be experienced by natural gas vehicles in cold climates.”
The 42-page report, replete with detailed analyses of fuel use, ambient conditions, engine conditions, loads, mileage logs, and driver behavior, has been endorsed by Canada’s Deployment Roadmap Technical Advisory Group (TAG), a government/industry group formed to address technical barriers related to medium and heavy natural gas vehicle adoption.
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Source: CNGVA with Fleets & Fuels follow-up