- Email: [email protected]
Comparison and evaluation of emissions for different driving cycles of motorcycles: A note
Transportation Research Part D 16 (2011) 61–64
Contents lists available at ScienceDirect
Transportation Research Part D journal homepage: www.elsevier.com/locate/trd
Notes and comments
Comparison and evaluation of emissions for different driving cycles of motorcycles: A note Ravindra Kumar a,⇑, B.K. Durai a, Wafaa Saleh b, Colin Boswell b a b
Central Road Research Institute, New Delhi, India Edinburgh Napier University, Scotland, UK
a r t i c l e
i n f o
Keywords: Motorcycle emissions Micro-simulation Edinburgh motorcycle driving cycle Measuring motorcycle emissions
a b s t r a c t On board, chassis dynamometer, and traffic micro-simulation emission measurement approaches are common ways of determining vehicle emission factors. Results from these various approaches are, however, significantly affected by factors such as the driving cycle, and engine size used. These variations are examined. Significant deviations in emission factors from regulatory standard are found for different driving cycle conditions and engine sizes for motorcycles in Edinburgh. Emissions of CO and HC measured using a chassis dynamometer over the Edinburgh motorcycle driving cycle, are found to differ from the results when using other measurement approaches. Crown Copyright Ó 2010 Published by Elsevier Ltd. All rights reserved.
1. Introduction Estimation of atmospheric emission factors for different vehicle types are limitation in their validity because of variations in the driving cycle and emission measurement techniques adopted. Cross checking and evaluation of results from different estimation approach, such as onboard emission measurement, chassis dynamometer measurements, and traffic micro-simulation (TMS) can help establish more reliable emission factors for motorcycles (Saleh et al., 2009) in actual driving condition. Here, motorcycle emissions of CO, HC, NOX are estimated using onboard measurements, chassis dynamometer, and micro-simulation modelling. Emission factors (EF) obtained from these approaches in an air quality management area (AQMA) of Edinburgh, Scotland are compared to existing regulatory standards. 2. Experimental methods The results using the three different approaches are presented in Table 1. 2.1. Onboard emission measurements Measured CO, HC and NOX emissions using onboard equipment are analysed using the carbon-mass-balance method (Tong et al., 2000). The emissions factors for 1000 cc engines are found to be 3.055, 0.038 and 0.009 g km 1 respectively, whereas for 600 cc engines they are 1.757, 0.041 and 0.004. Instantaneous speed during onboard measurements is also used to estimate the emissions in local conditions using the National Atmospheric Emission Inventory (NAEI) coefficient (Barlow et al., 2001). The estimated average value of EFs CO, HC and NOX emissions for the 1000 cc engines are 21.8, 1.212 and 0.39 g km 1, and for 600 cc engines, 8.28, 1.34 and 1.54 g km 1 (Table 1). ⇑ Corresponding author. Tel.: +91 11 26310087; fax: +91 11 26845943. E-mail address: [email protected] (R. Kumar). 1361-9209/$ - see front matter Crown Copyright Ó 2010 Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.trd.2010.08.006
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R. Kumar et al. / Transportation Research Part D 16 (2011) 61–64
Table 1 Emission factors measured on different driving cycles. Sources
Regulatory standard
Measured on chassis dynamometer
Using onboard emission approach Micro-simulation approach
Pollutant (g km
1
)
CO
HC
NOX
Engine size (cc)
600
1000
600
1000
600
1000
WMTC standard urban WMTC standard rural WMTC standard highway Euro 1 standard Euro 2 standard Euro 3 standard ECE 40 measured EMDC rural EMDC urban WMTC measured part 1 WMTC measured part 2 WMTC measured part 3 Using analyser Using NAEI emission coefficient Using NAEI emission factor coefficient
2.62 7.40 2.90 8.00 5.50 2.00 15.90 9.40 13.10 10.00 17.60 34.90 1.76 8.28 10.58
2.62 7.40 2.90 8.00 5.50 2.00 34.20 36.90 44.10 36.80 43.20 38.00 3.05 21.80 26.70
0.75 0.50 0.20 4.00 1.00 0.30 2.40 1.60 4.40 3.0 1.90 2.10 0.04 1.34 1.90
0.75 0.50 0.20 4.00 1.00 0.30 2.80 1.50 3.70 3.00 1.80 1.20 0.04 1.21 1.72
0.17 0.10 0.50 1.00 0.30 0.20 0.10 0.10 0.20 0.10 0.10 0.20 0.01 1.54 1.14
0.17 0.10 0.50 1.00 0.30 0.20 0.20 0.10 0.30 0.10 0.20 0.60 0.01 0.39 0.28
2.2. Micro-simulation approach Using micro-simulation, average values of CO, HC and NOX emissions for the 1000 cc engine are estimated as 26.7, 1.72 and 0.283 g km 1, and 10.581, 1.90 and 0.283 g km 1 for 600 cc engines. 2.3. Chassis dynamometer approach The Edinburgh motorcycle driving cycle (EMDC), European driving cycle (ECE) and world motorcycle test cycle (WMTC) are used to measure the emissions of CO, HC and NOX for 1000 cc and 600 cc engines on chassis dynamometer approach. For 1000 cc engines, CO and NOX emissions are highest whereas for the 600 cc engines, HC emissions are found to be greatest in the EMDC urban cycle. NOX emissions are 0.6 g km 1 for the WMTC measured part 3, as opposed to only 0.1 g km 1 for EMDC rural. The emissions were greatest for the larger engine size. 3. Emission factors for different driving cycle and methods Four regulatory standards – Euro 1, Euro 2, Euro 3 and the WMTC – are used as benchmarks for comparing the results from the various measurement approaches. Tables 2 and 3 provide the variations in outputs for the urban and rural driving cycles. The urban EMDC for the chassis dynamometer produces the highest emissions compared to the standard regulatory emission factors, but its use for the rural EMDC shows less variation for the rural cycles when compared to the WMTC and to the Euro emission standards. The onboard emission factor for NOX using instantaneous speed showed large variations for the similar pattern of the urban EMDC driving cycle; such deviations emphasis the effect of local urban driving cycles used in estimation of the emission factors. Overall consistency of the estimated EFs is found to be sensitive to both the type of pollutant considered and the driving cycle, with NOX in the EF results being more consistent than those for other pollutants. 4. Comparison of results CO emissions as measured using the chassis dynamometer and micro-simulation approaches do not meet current UK regulatory standards. In fact, in some cases such measurements exceed the regulatory standards for EFs by 2100% – Euro 3 for 1000 cc engines. These deviations are largest for the WMTC and Euro 3 cycle because they are the latest criteria and are stricter emission norms than Euro 1, Euro 2, and pre-Euro standards. Also, the higher emissions in the EMDC are because of the greater amount of acceleration and deceleration in the cycle. Because, the EMDC is an actual driving cycle, the overall emission factors for CO and HC using the chassis dynamometer for the urban cycle are found to be higher than those from the micro-simulation and onboard emission approaches, whereas, NOX emissions from the urban EMDCs chassis dynamometer tests are different between 0.15% and 800% to the regulatory emission standards both Euro and the WMTC. The variable effect of actual driving on NOX emissions is due in differences caused by the affect on the lean air–fuel ratio source from excessive engine-temperatures produced by the frequent accelerations and decelerations observed in Edinburgh. Emission factors obtained using micro-simulations and onboard emission measurements using the NAEI database are reasonably similar with exception of the NOX emissions. The EFs obtained for NOX using these methods show little variation because they are estimated using actual speeds of motorcycles along the AQMA test corridor in Edinburgh and based on instantaneous speed rather than average speed.
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R. Kumar et al. / Transportation Research Part D 16 (2011) 61–64 Table 2 Percentage deviations from regulatory standards for urban driving conditions. Driving cycle
Regulatory standard
Pollutant
CO
Engine size (cc)
600
ECE 40 measured EMDC urban WMTC measured part 1 On board using analyser On board using NAEI emission coefficient Micro-simulation using NAEI emission factor coefficient
% Deviation from WMTC standard 506.87 1205.34 220.00 400.00 1583.21 486.67 281.68 1304.58 300.00 32.94 16.53 94.67 216.03 732.06 78.67 303.82 919.08 153.33
ECE 40 measured EMDC urban WMTC measured part 1 On board using analyser On board using NAEI emission coefficient Micro-simulation using NAEI emission factor coefficient
HC 1000
NOX
600
1000
600
1000
273.33 393.33 300.00 94.93 62.13 129.33
41.18 17.65 41.18 95.29 808.24 570.59
17.65 76.47 41.18 97.65 134.71 66.47
% Deviation from Euro 1 standard 98.75 327.50 40.00 63.75 451.25 10.00 25.00 360.00 25.00 78.04 61.84 99.00 3.50 172.50 66.50 32.25 233.75 52.50
30.00 7.50 25.00 99.05 69.60 57.00
0.90 0.80 0.90 0.99 0.54 0.14
0.80 0.70 0.90 1.00 0.60 0.72
ECE 40 measured EMDC urban WMTC measured part 1 On board using analyser On board using NAEI emission coefficient Micro-simulation using NAEI emission factor coefficient
% Deviation from Euro 2 standard 189.09 521.82 140.00 138.18 701.82 340.00 81.82 569.09 200.00 68.05 44.49 96.00 50.55 296.36 34.00 92.36 385.45 90.00
180.00 270.00 200.00 96.20 21.60 72.00
66.67 33.33 66.67 97.33 414.67 280.00
33.33 0.00 66.67 98.67 33.00 5.67
ECE 40 measured EMDC urban WMTC measured part 1 On board using analyser On board using NAEI emission coefficient Micro-simulation using NAEI emission factor coefficient
% Deviation from Euro 3 standard 695.00 1610.00 700.00 555.00 2105.00 1366.67 400.00 1740.00 900.00 12.15 52.65 86.67 314.00 990.00 346.67 429.00 1235.00 533.33
833.33 1133.33 900.00 87.33 305.33 473.33
50.00 0.00 50.00 96.00 672.00 470.00
0.00 50.00 50.00 98.00 99.50 41.50
Note: Bold indicates the greatest deviation.
Table 3 Percentage deviations from regulatory standards for rural driving conditions. Pollutants
CO
Engine size (cc)
600
% Deviation from WMTC EMDC rural WMTC measured part 2
27.03 137.84
% Deviation from Euro 1 EMDC rural WMTC measured part 2
HC 1000
NOX
600
1000
600
1000
398.65 483.78
220.00 280.00
200.00 260.00
0.00 0.00
0.00 100.00
17.50 120.00
361.25 440.00
60.00 52.50
62.50 55.00
90.00 90.00
90.00 80.00
% Deviation from Euro 2 EMDC rural WMTC measured part 2
70.91 220.00
570.91 685.45
60.00 90.00
50.00 80.00
66.67 66.67
66.67 33.33
% Deviation from Euro 3 EMDC rural WMTC measured part 2
370.00 780.00
1745.00 2060.00
60.00 90.00
50.00 80.00
66.67 66.67
66.67 33.33
Note: Bold indicates the greatest deviation.
Across the range of emission measurement approaches, onboard emission measurements are found to be lowest for all pollutants, with variations at least partly attributable to conversion problems in g km 1 and calibration errors, as well as time alignment issues during the sampling and measurement process. The onboard approach has advantages over chassis dynamometer and micro-simulation measurements because it embraces the actual fluctuations of instantaneous emissions during different vehicle operating modes rather than for simulations under laboratory condition. The CO emissions are found to increase with engine size and the HC emissions factors are less sensitive to engine size than are levels of CO; HC emissions decrease with increases in engine size. For NOX emissions, the effect of engine size is dependent on the emission measurement methodology; the chassis dynamometer emission shows increases for larger engine sizes.
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R. Kumar et al. / Transportation Research Part D 16 (2011) 61–64
References Barlow, T.J., Hickman, A.J., Boulter, P.G., 2001. Exhaust emission factors 2001: database and emission factors. Transport Research Laboratory. Report PR/SE/ 230/00, Crowthorne. Saleh, W., Kumar, R., Kirby, H., Kumar, P., 2009. Real world driving cycle for motorcycles in Edinburgh. Transportation Research Part D 14, 326–333. Tong, H.Y., Hung, W.T., Cheung, C.S., 2000. On-road motor vehicle emissions and fuel consumption in urban driving conditions. Journal of Air Waste Management Association 50, 543–554.
Contents lists available at ScienceDirect
Transportation Research Part D journal homepage: www.elsevier.com/locate/trd
Notes and comments
Comparison and evaluation of emissions for different driving cycles of motorcycles: A note Ravindra Kumar a,⇑, B.K. Durai a, Wafaa Saleh b, Colin Boswell b a b
Central Road Research Institute, New Delhi, India Edinburgh Napier University, Scotland, UK
a r t i c l e
i n f o
Keywords: Motorcycle emissions Micro-simulation Edinburgh motorcycle driving cycle Measuring motorcycle emissions
a b s t r a c t On board, chassis dynamometer, and traffic micro-simulation emission measurement approaches are common ways of determining vehicle emission factors. Results from these various approaches are, however, significantly affected by factors such as the driving cycle, and engine size used. These variations are examined. Significant deviations in emission factors from regulatory standard are found for different driving cycle conditions and engine sizes for motorcycles in Edinburgh. Emissions of CO and HC measured using a chassis dynamometer over the Edinburgh motorcycle driving cycle, are found to differ from the results when using other measurement approaches. Crown Copyright Ó 2010 Published by Elsevier Ltd. All rights reserved.
1. Introduction Estimation of atmospheric emission factors for different vehicle types are limitation in their validity because of variations in the driving cycle and emission measurement techniques adopted. Cross checking and evaluation of results from different estimation approach, such as onboard emission measurement, chassis dynamometer measurements, and traffic micro-simulation (TMS) can help establish more reliable emission factors for motorcycles (Saleh et al., 2009) in actual driving condition. Here, motorcycle emissions of CO, HC, NOX are estimated using onboard measurements, chassis dynamometer, and micro-simulation modelling. Emission factors (EF) obtained from these approaches in an air quality management area (AQMA) of Edinburgh, Scotland are compared to existing regulatory standards. 2. Experimental methods The results using the three different approaches are presented in Table 1. 2.1. Onboard emission measurements Measured CO, HC and NOX emissions using onboard equipment are analysed using the carbon-mass-balance method (Tong et al., 2000). The emissions factors for 1000 cc engines are found to be 3.055, 0.038 and 0.009 g km 1 respectively, whereas for 600 cc engines they are 1.757, 0.041 and 0.004. Instantaneous speed during onboard measurements is also used to estimate the emissions in local conditions using the National Atmospheric Emission Inventory (NAEI) coefficient (Barlow et al., 2001). The estimated average value of EFs CO, HC and NOX emissions for the 1000 cc engines are 21.8, 1.212 and 0.39 g km 1, and for 600 cc engines, 8.28, 1.34 and 1.54 g km 1 (Table 1). ⇑ Corresponding author. Tel.: +91 11 26310087; fax: +91 11 26845943. E-mail address: [email protected] (R. Kumar). 1361-9209/$ - see front matter Crown Copyright Ó 2010 Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.trd.2010.08.006
62
R. Kumar et al. / Transportation Research Part D 16 (2011) 61–64
Table 1 Emission factors measured on different driving cycles. Sources
Regulatory standard
Measured on chassis dynamometer
Using onboard emission approach Micro-simulation approach
Pollutant (g km
1
)
CO
HC
NOX
Engine size (cc)
600
1000
600
1000
600
1000
WMTC standard urban WMTC standard rural WMTC standard highway Euro 1 standard Euro 2 standard Euro 3 standard ECE 40 measured EMDC rural EMDC urban WMTC measured part 1 WMTC measured part 2 WMTC measured part 3 Using analyser Using NAEI emission coefficient Using NAEI emission factor coefficient
2.62 7.40 2.90 8.00 5.50 2.00 15.90 9.40 13.10 10.00 17.60 34.90 1.76 8.28 10.58
2.62 7.40 2.90 8.00 5.50 2.00 34.20 36.90 44.10 36.80 43.20 38.00 3.05 21.80 26.70
0.75 0.50 0.20 4.00 1.00 0.30 2.40 1.60 4.40 3.0 1.90 2.10 0.04 1.34 1.90
0.75 0.50 0.20 4.00 1.00 0.30 2.80 1.50 3.70 3.00 1.80 1.20 0.04 1.21 1.72
0.17 0.10 0.50 1.00 0.30 0.20 0.10 0.10 0.20 0.10 0.10 0.20 0.01 1.54 1.14
0.17 0.10 0.50 1.00 0.30 0.20 0.20 0.10 0.30 0.10 0.20 0.60 0.01 0.39 0.28
2.2. Micro-simulation approach Using micro-simulation, average values of CO, HC and NOX emissions for the 1000 cc engine are estimated as 26.7, 1.72 and 0.283 g km 1, and 10.581, 1.90 and 0.283 g km 1 for 600 cc engines. 2.3. Chassis dynamometer approach The Edinburgh motorcycle driving cycle (EMDC), European driving cycle (ECE) and world motorcycle test cycle (WMTC) are used to measure the emissions of CO, HC and NOX for 1000 cc and 600 cc engines on chassis dynamometer approach. For 1000 cc engines, CO and NOX emissions are highest whereas for the 600 cc engines, HC emissions are found to be greatest in the EMDC urban cycle. NOX emissions are 0.6 g km 1 for the WMTC measured part 3, as opposed to only 0.1 g km 1 for EMDC rural. The emissions were greatest for the larger engine size. 3. Emission factors for different driving cycle and methods Four regulatory standards – Euro 1, Euro 2, Euro 3 and the WMTC – are used as benchmarks for comparing the results from the various measurement approaches. Tables 2 and 3 provide the variations in outputs for the urban and rural driving cycles. The urban EMDC for the chassis dynamometer produces the highest emissions compared to the standard regulatory emission factors, but its use for the rural EMDC shows less variation for the rural cycles when compared to the WMTC and to the Euro emission standards. The onboard emission factor for NOX using instantaneous speed showed large variations for the similar pattern of the urban EMDC driving cycle; such deviations emphasis the effect of local urban driving cycles used in estimation of the emission factors. Overall consistency of the estimated EFs is found to be sensitive to both the type of pollutant considered and the driving cycle, with NOX in the EF results being more consistent than those for other pollutants. 4. Comparison of results CO emissions as measured using the chassis dynamometer and micro-simulation approaches do not meet current UK regulatory standards. In fact, in some cases such measurements exceed the regulatory standards for EFs by 2100% – Euro 3 for 1000 cc engines. These deviations are largest for the WMTC and Euro 3 cycle because they are the latest criteria and are stricter emission norms than Euro 1, Euro 2, and pre-Euro standards. Also, the higher emissions in the EMDC are because of the greater amount of acceleration and deceleration in the cycle. Because, the EMDC is an actual driving cycle, the overall emission factors for CO and HC using the chassis dynamometer for the urban cycle are found to be higher than those from the micro-simulation and onboard emission approaches, whereas, NOX emissions from the urban EMDCs chassis dynamometer tests are different between 0.15% and 800% to the regulatory emission standards both Euro and the WMTC. The variable effect of actual driving on NOX emissions is due in differences caused by the affect on the lean air–fuel ratio source from excessive engine-temperatures produced by the frequent accelerations and decelerations observed in Edinburgh. Emission factors obtained using micro-simulations and onboard emission measurements using the NAEI database are reasonably similar with exception of the NOX emissions. The EFs obtained for NOX using these methods show little variation because they are estimated using actual speeds of motorcycles along the AQMA test corridor in Edinburgh and based on instantaneous speed rather than average speed.
63
R. Kumar et al. / Transportation Research Part D 16 (2011) 61–64 Table 2 Percentage deviations from regulatory standards for urban driving conditions. Driving cycle
Regulatory standard
Pollutant
CO
Engine size (cc)
600
ECE 40 measured EMDC urban WMTC measured part 1 On board using analyser On board using NAEI emission coefficient Micro-simulation using NAEI emission factor coefficient
% Deviation from WMTC standard 506.87 1205.34 220.00 400.00 1583.21 486.67 281.68 1304.58 300.00 32.94 16.53 94.67 216.03 732.06 78.67 303.82 919.08 153.33
ECE 40 measured EMDC urban WMTC measured part 1 On board using analyser On board using NAEI emission coefficient Micro-simulation using NAEI emission factor coefficient
HC 1000
NOX
600
1000
600
1000
273.33 393.33 300.00 94.93 62.13 129.33
41.18 17.65 41.18 95.29 808.24 570.59
17.65 76.47 41.18 97.65 134.71 66.47
% Deviation from Euro 1 standard 98.75 327.50 40.00 63.75 451.25 10.00 25.00 360.00 25.00 78.04 61.84 99.00 3.50 172.50 66.50 32.25 233.75 52.50
30.00 7.50 25.00 99.05 69.60 57.00
0.90 0.80 0.90 0.99 0.54 0.14
0.80 0.70 0.90 1.00 0.60 0.72
ECE 40 measured EMDC urban WMTC measured part 1 On board using analyser On board using NAEI emission coefficient Micro-simulation using NAEI emission factor coefficient
% Deviation from Euro 2 standard 189.09 521.82 140.00 138.18 701.82 340.00 81.82 569.09 200.00 68.05 44.49 96.00 50.55 296.36 34.00 92.36 385.45 90.00
180.00 270.00 200.00 96.20 21.60 72.00
66.67 33.33 66.67 97.33 414.67 280.00
33.33 0.00 66.67 98.67 33.00 5.67
ECE 40 measured EMDC urban WMTC measured part 1 On board using analyser On board using NAEI emission coefficient Micro-simulation using NAEI emission factor coefficient
% Deviation from Euro 3 standard 695.00 1610.00 700.00 555.00 2105.00 1366.67 400.00 1740.00 900.00 12.15 52.65 86.67 314.00 990.00 346.67 429.00 1235.00 533.33
833.33 1133.33 900.00 87.33 305.33 473.33
50.00 0.00 50.00 96.00 672.00 470.00
0.00 50.00 50.00 98.00 99.50 41.50
Note: Bold indicates the greatest deviation.
Table 3 Percentage deviations from regulatory standards for rural driving conditions. Pollutants
CO
Engine size (cc)
600
% Deviation from WMTC EMDC rural WMTC measured part 2
27.03 137.84
% Deviation from Euro 1 EMDC rural WMTC measured part 2
HC 1000
NOX
600
1000
600
1000
398.65 483.78
220.00 280.00
200.00 260.00
0.00 0.00
0.00 100.00
17.50 120.00
361.25 440.00
60.00 52.50
62.50 55.00
90.00 90.00
90.00 80.00
% Deviation from Euro 2 EMDC rural WMTC measured part 2
70.91 220.00
570.91 685.45
60.00 90.00
50.00 80.00
66.67 66.67
66.67 33.33
% Deviation from Euro 3 EMDC rural WMTC measured part 2
370.00 780.00
1745.00 2060.00
60.00 90.00
50.00 80.00
66.67 66.67
66.67 33.33
Note: Bold indicates the greatest deviation.
Across the range of emission measurement approaches, onboard emission measurements are found to be lowest for all pollutants, with variations at least partly attributable to conversion problems in g km 1 and calibration errors, as well as time alignment issues during the sampling and measurement process. The onboard approach has advantages over chassis dynamometer and micro-simulation measurements because it embraces the actual fluctuations of instantaneous emissions during different vehicle operating modes rather than for simulations under laboratory condition. The CO emissions are found to increase with engine size and the HC emissions factors are less sensitive to engine size than are levels of CO; HC emissions decrease with increases in engine size. For NOX emissions, the effect of engine size is dependent on the emission measurement methodology; the chassis dynamometer emission shows increases for larger engine sizes.
64
R. Kumar et al. / Transportation Research Part D 16 (2011) 61–64
References Barlow, T.J., Hickman, A.J., Boulter, P.G., 2001. Exhaust emission factors 2001: database and emission factors. Transport Research Laboratory. Report PR/SE/ 230/00, Crowthorne. Saleh, W., Kumar, R., Kirby, H., Kumar, P., 2009. Real world driving cycle for motorcycles in Edinburgh. Transportation Research Part D 14, 326–333. Tong, H.Y., Hung, W.T., Cheung, C.S., 2000. On-road motor vehicle emissions and fuel consumption in urban driving conditions. Journal of Air Waste Management Association 50, 543–554.