Date of Graduation
2005
Document Type
Thesis
Degree Type
MS
Committee Chair
Gregory J. Thompson
Abstract
A study was conducted to evaluate the accuracy of an air-to-fuel ratio derived exhaust flow rate for emissions testing. The Mobile Emissions Measurement System (MEMS) was developed by West Virginia University to perform in-use emissions testing for several heavy-duty diesel engine manufactures. The MEMS was modified to complete this study. A review of literature describing different on-board systems and flow measurement techniques was performed to aid in the completion of this project. Most of the exhaust flow measurement techniques require the modification of the test vehicle’s exhaust system. The air-to-fuel ratio derived exhaust flow rate only requires a probe to obtain an exhaust sample. The gaseous emissions were measured to calculate an air-to-fuel ratio. The air-to-fuel ratio was combined with the vehicle’s fuel rate to obtain the total exhaust volumetric flow rate. The air-to-fuel ratio derived flow rate was compared to the MEMS reported and theoretical flow rates. The study found that the method produces its best result under steady state conditions. The results produced under motoring and extreme transient conditions where found to be inaccurate. The overall correlations when the air-to-fuel ratio derived flow rate was compared to MEMS and theoretical flow rates produced good results with R2 values of 0.985 and 0.988 respectively. When the flow rates were combined with the CO2 data to obtain total fuel consumptions the method compared well with percent differences below 2%.
Recommended Citation
Bolyard, Jason D., "Evaluation of an air-to-ratio derived exhaust flow rate for in-use emissions testing." (2005). Graduate Theses, Dissertations, and Problem Reports (ETD). 10925.
https://researchrepository.wvu.edu/etd/10925