ENGINE VARIABLE IMPACT ANALYSIS OF FUEL USE AND EMISSIONS FOR HEAVY DUTY DIESEL MAINTENANCE EQUIPMENT

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1 ENGINE VARIABLE IMPACT ANALYSIS OF FUEL USE AND EMISSIONS FOR HEAVY DUTY DIESEL MAINTENANCE EQUIPMENT Phil Lewis, PhD, PE Oklahoma State University Heni Fitriani, PhD University of Sriwijaya (Indonesia) Ingrid Arocho, PhD Oregon State University

2 2/3/ th Annual Meeting of Transportation Research Board 2 Heavy Duty Diesel Equipment Emissions 6 Billion Gallons of Diesel Fuel NO x = 657,000 tons PM = 63,000 tons CO = 1,100,000 tons CO 2 = 67,000,000 tons 2 Million Items of Nonroad Equipment HC Precursor to Ground Level Ozone

3 2/3/ th Annual Meeting of Transportation Research Board 3 Diesel Emissions Impacts H E A L T H E N V I R O N M E N T Allergies Asthma Heart/Lung Issues Smog Acid Rain Global Warming

4 2/3/ th Annual Meeting of Transportation Research Board 4 EPA Diesel Emissions Regulations ENVIRONMENTAL STANDARDS NAAQS Pollutants NOx PM CO O 3 HC EQUIPMENT STANDARDS Tier 0 Tier 1 Tier 2 Tier 3 Tier 4

5 2/3/ th Annual Meeting of Transportation Research Board 5 Research Question Which engine variables have the greatest impact on fuel use and pollutant emission rates for HDD equipment?

6 2/3/ th Annual Meeting of Transportation Research Board 6 Case Study Fleet Equipment Horsepower Displacement Model Engine Data (HP) (Liters) Year Tier (s) Backhoe ,780 Backhoe ,407 Backhoe ,853 Backhoe ,406 Backhoe ,379 Motor Grader ,293 Motor Grader ,767 Motor Grader ,590 Motor Grader ,040 Motor Grader ,788 Motor Grader ,757 Wheel Loader ,226 Wheel Loader ,064 Wheel Loader ,404 Wheel Loader ,718 Wheel Loader ,827

7 2/3/ th Annual Meeting of Transportation Research Board 7 Equipment Data Collection NO x, PM, HC, CO, & CO 2 IAT, MAP, RPM

8 2/3/ th Annual Meeting of Transportation Research Board 8 Analytical Methodology Multiple Linear Regression where: Y 1-6 X 1 X 2 X 3 Y 1-6 = β 0 + β 1 X 1 + β 2 X 2 + β 3 X 3 = Fuel Use, NO x, HC, CO, CO 2, or PM (grams per second) = Manifold Absolute Pressure (kilopascal) = Engine Speed (RPM) = Intake Air Temperature (Celsius degrees) β 0, β 1, β 2, β 3 = Coefficients of linear relationship

9 2/3/ th Annual Meeting of Transportation Research Board 9 Variable Impact Analysis The purpose of variable impact analysis (VIA) is to measure the sensitivity of prediction models to changes in independent variables Every independent variable is assigned a relative variable impact value; these are percent values and sum to 100% The lower the percent value for a given variable, the less impact the variable has on the predictions VIA is used to determine the relative impact of RPM, MAP, and IAT on predicting fuel use and emission rates of NO x, HC, CO, CO 2, and PM

10 2/3/ th Annual Meeting of Transportation Research Board 10 Summary Statistics Backhoes Equipment MAP RPM IAT Fuel NO x HC CO CO 2 PM (kpa) (rpm) (C) (g/s) (g/s) (g/s) (g/s) (g/s) (g/s) Backhoe Backhoe , Backhoe , Backhoe , Backhoe , Average 106 1,

11 2/3/ th Annual Meeting of Transportation Research Board 11 Summary Statistics Motor Graders Equipment MAP RPM IAT Fuel NO x HC CO CO 2 PM (kpa) (rpm) (C) (g/s) (g/s) (g/s) (g/s) (g/s) (g/s) Motor Grader , Motor Grader , Motor Grader , Motor Grader , Motor Grader , Motor Grader , Average 140 1,

12 2/3/ th Annual Meeting of Transportation Research Board 12 Summary Statistics Wheel Loaders Equipment MAP RPM IAT Fuel NO x HC CO CO 2 PM (kpa) (rpm) (C) (g/s) (g/s) (g/s) (g/s) (g/s) (g/s) Wheel Loader , Wheel Loader , Wheel Loader , Wheel Loader , Wheel Loader , Average 118 1,

13 2/3/ th Annual Meeting of Transportation Research Board 13 MLR R 2 Values Equipment Fuel Use NO x HC CO CO 2 PM Backhoe Backhoe Backhoe Backhoe Backhoe Average Motor Grader Motor Grader Motor Grader Motor Grader Motor Grader Motor Grader Average Wheel Loader Wheel Loader Wheel Loader Wheel Loader Wheel Loader Average Overall Average

14 2/3/ th Annual Meeting of Transportation Research Board 14 Variable Impact Analysis Equipment Variable Fuel Use NO x HC CO CO 2 PM MAP Backhoes RPM (n = 5) IAT Total Motor Graders (n = 6) Wheel Loaders (n = 5) Overall (n = 16) MAP RPM IAT Total MAP RPM IAT Total MAP RPM IAT Total

15 2/3/ th Annual Meeting of Transportation Research Board 15 Simple Linear Regression Models MAP norm = where: MAP norm = Normalized MAP (%) MAP i MAP min MAP max MAP i MAP min MAP max MAP min = MAP value at time i (kilopascal) = Minimum MAP value (kilopascal) = Maximum MAP value (kilopascal) where: Y 1-6 m Y 1-6 = mx + b = Fuel use or emission rate of NO x, HC, CO, CO 2, or PM = slope of the regression line X = Engine load (%) (or MAP norm ) b = y-intercept

16 2/3/ th Annual Meeting of Transportation Research Board 16 SLR R 2 Values Equipment Fuel Use NO x HC CO CO 2 PM Backhoe Backhoe Backhoe Backhoe Backhoe Average Motor Grader Motor Grader Motor Grader Motor Grader Motor Grader Motor Grader Average Wheel Loader Wheel Loader Wheel Loader Wheel Loader Wheel Loader Average Overall Average

17 2/3/ th Annual Meeting of Transportation Research Board 17 SLR Model Results Y = mx + b, where X = Engine Load Tier 0 Tier 1 Tier 2 Y m b m b m b Fuel Use (gal/h) NO x (lb/h) HC (lb/h) CO (lb/h) CO 2 (lb/h) PM (g/h)

18 Engine Load 2/3/ th Annual Meeting of Transportation Research Board 18 Cumulative Frequency Diagram 100% 80% 60% 40% 20% Backhoes Motor Graders Wheel Loaders 0% 0% 20% 40% 60% 80% 100% Time

19 2/3/ th Annual Meeting of Transportation Research Board 19 Conclusions MAP, followed by RPM, has the greatest impact on mass per time rates of fuel use, NO x, CO, CO 2, and PM; RPM, followed by MAP, has the greatest impact on mass per time rates of HC; IAT has the least impact on mass per time rates of fuel use, NO x, HC, CO, CO 2, and PM; HC and CO are difficult to predict because of high variability in the data; and SLR models provide a practical and statistically defensible fuel use and emissions estimating tool for backhoes, motor graders, and wheel loaders.

20 2/3/ th Annual Meeting of Transportation Research Board 20 Recommendations Other types of equipment should be included in the study; Other equipment variables, such as engine horsepower and gross vehicle weight, should be included in the study; Mass per fuel used emission rates may be used to estimate emissions inventories by fleet owners that keep meticulous fuel use records; Fuel use forecasts should help improve estimates of equipment operating costs as well as total highway maintenance activity costs; and Fleet managers, particularly those that oversee publicly owned fleets, should not overlook the environmental impacts of their equipment.