scholarly journals Does California’s EMFAC2017 Vehicle Emissions Model Under-predict California Light-duty Gasoline Vehicle NOx Emissions?

2021 ◽  
Author(s):  
Gary A. Bishop
Keyword(s):  
Vehicle Emissions ◽  
Nox Emissions ◽  
Light Duty

Analysis of emissions from various driving cycles based on real driving measurements obtained in a high-altitude city

2020 ◽  
Vol 234 (6) ◽  
pp. 1563-1571 ◽  
Author(s):  
Meng Lyu ◽  
Xiaofeng Bao ◽  
Yunjing Wang ◽  
Ronald Matthews
Keyword(s):  
High Altitude ◽  
Real World ◽  
Vehicle Emissions ◽  
Control Strategies ◽  
Driving Cycle ◽  
Specific Power ◽  
Test Cycle ◽  
Light Duty ◽  
And Control ◽  
Light Duty Vehicles

Vehicle emissions standards and regulations remain weak in high-altitude regions. In this study, vehicle emissions from both the New European Driving Cycle and the Worldwide harmonized Light-duty driving Test Cycle were analyzed by employing on-road test data collected from typical roads in a high-altitude city. On-road measurements were conducted on five light-duty vehicles using a portable emissions measurement system. The certification cycle parameters were synthesized from real-world driving data using the vehicle specific power methodology. The analysis revealed that under real-world driving conditions, all emissions were generally higher than the estimated values for both the New European Driving Cycle and Worldwide harmonized Light-duty driving Test Cycle. Concerning emissions standards, more CO, NOx, and hydrocarbons were emitted by China 3 vehicles than by China 4 vehicles, whereas the CO2 emissions exhibited interesting trends with vehicle displacement and emissions standards. These results have potential implications for policymakers in regard to vehicle emissions management and control strategies aimed at emissions reduction, fleet inspection, and maintenance programs.

Cycle-to-Cycle NO and NOx Emissions From a HSDI Diesel Engine

2018 ◽  
Author(s):  
Felix Leach ◽  
Martin Davy ◽  
Mark Peckham
Keyword(s):  
Diesel Engine ◽  
High Speed ◽  
Nox Emissions ◽  
Nox Formation ◽  
Reduction Techniques ◽  
Light Duty ◽  
Peak Cylinder Pressure ◽  
Crank Angle ◽  
The Difference ◽  
Hsdi Diesel Engine

Engine-out NOx emissions from diesel engines continue to be a major topic of research interest. While substantial understanding has been obtained of engine-out (i.e. before any aftertreatment) NOx formation and reduction techniques, not least EGR which is now well established and fitted to production vehicles, much less data are available on cycle resolved NOx emissions. In this work, crank-angle resolved NO and NOx measurements have been taken from a high-speed light duty diesel engine at test conditions both with and without EGR. These have been combined with 1D data of exhaust flow and this used to form a mass average of NO and NOx emissions per cycle. These results have been compared with combustion data and other emissions. The results show that there is a very strong correlation (R2 > 0.95) between the NOx emitted per cycle and the peak cylinder pressure of that cycle. In addition, the crank-angle resolved NO and NOx measurements also reveal that there is a difference in NO : NO2 ratio (where NO2 is assumed to be the difference between NO and NOx) during the exhaust period, with proportionally more NO2 being emitted during the blowdown period compared to the rest of the exhaust stroke.

Detailed Evaluation of a New Semi-Empirical Two-Zone NOx Model by Application on Various Diesel Engine Configurations

2012 ◽  
Author(s):  
Stelios Provataris ◽  
Nicholas Savva ◽  
Dimitrios Hountalas
Keyword(s):  
Diesel Engine ◽  
Accurate Estimation ◽  
Operating Parameters ◽  
Nox Emissions ◽  
Heavy Duty ◽  
Nox Formation ◽  
Light Duty ◽  
Physically Based ◽  
Di Diesel Engine ◽  
Semi Empirical

Over a significant period of time, efforts have been made towards a valid and accurate estimation of DI diesel engine NOx emissions. Considering the fact that experiments have a high cost in both time and money, modelling approaches have been developed in an effort to overcome these issues. It is well known that accuracy in the prediction of NOx emissions lies specifically on the accurate estimation of local temperature and O2 histories inside the combustion chamber that govern NOx formation, fulfilled by an accurate estimation of the combustion mechanism. To account for the actual effect of parameters that control NOx formation and overcome inefficiencies introduced from existing purely empirical models or artificial neural networks, valid only on the combustion systems for which they were developed [1], an alternative solution is the introduction of physically based semi-empirical models. Towards this direction, in the present work is presented and evaluated a new modelling approach, based on the combustion rate obtained from the measured cylinder pressure trace using Heat Release Rate Analysis. The model used is a semi-empirical two-zone one which makes use of the estimated elementary fuel mass burnt at each crank angle interval. The combustion process is considered to be adiabatic, while chemical dissociation is also considered. With this approach, temperature distribution throughout the combustion chamber is considered for, together with its evolution during the engine cycle. In addition, O2 availability is also considered for through the calculated charge composition. The result is an extremely fast computational model, combining the advantages of both empirical and physically based ones. In the present work is given a detailed validation of the model, from its application on two different types of diesel engines: a heavy-duty DI diesel engine and a light-duty DI diesel engine with pilot fuel injection. A significant number of cases where tested for both engine configurations, considering different operation points and variation of operating parameters, such as rail pressure and EGR. The twelve points of the European Stationary Cycle (ESC) were covered for the case of the heavy duty DI diesel engine, whilst for the light-duty DI engine a total number of forty-six operating points was studied. For both engine configurations the model reveals a very good predictive ability, considering for the effect of all operating parameters examined on NOx emissions. However, there is potential for improvement and development on its physical base for even more accurate predictions. The merits of good accuracy in prediction trends with varying engine operating parameters — even without calibration — and low computational time establish a potential for model use in engine development, optimization studies and model based control applications.

Recent evidence concerning higher NOx emissions from passenger cars and light duty vehicles

2011 ◽  
Vol 45 (39) ◽  
pp. 7053-7063 ◽  
Author(s):  
David C. Carslaw ◽  
Sean D. Beevers ◽  
James E. Tate ◽  
Emily J. Westmoreland ◽  
Martin L. Williams
Keyword(s):  
Nox Emissions ◽  
Passenger Cars ◽  
Light Duty ◽  
Light Duty Vehicles

Emission and Performance Analysis of a Light Duty Common Rail Direct Inject Engine Fuelled by CME-Diesel Blends

2017 ◽  
Author(s):  
Jose Gabriel E. Mercado ◽  
Edwin N. Quiros
Keyword(s):  
The Philippines ◽  
Common Rail ◽  
Emission Characteristics ◽  
Nox Emissions ◽  
Biodiesel Blends ◽  
Performance And Emission ◽  
Light Duty ◽  
Speed Range ◽  
Biodiesel Blend ◽  
Emission Limits

Due to the danger of depletion of world petroleum reserve and environmental concerns the “Philippines Biofuels Act of 2006” (Republic Act No. 9367) was established to develop and strengthen the use of local sustainable fuels, particularly the use of Coconut Methyl Ester (CME) biodiesel blends in the country. As of 2015, with respect to biodiesel in the Philippines only 2% of biodiesel is required to be blended in commercially available fuels. The National Biofuels Board of the Philippines is planning to increase the percentage of the blend within the next 5 years however only few studies are conducted to prove the effectiveness of the increase in percentage. Also in pursuant to “Philippine Clean Air Act of 2009” (Republic Act No.8749) The Department of Environmental and Natural Resources (DENR) issued an administrative order with regards to the implementation of EURO 4/IV Emission Limits within the country. This study investigates the influence of various CME Biodiesel blends in a light duty automotive CRDi engine without any engine modifications through evaluation of performance and emission characteristics, The emission characteristics will be also be investigated if it meets the EURO 4/IV emission limits set by DENR. Five fuel blends B2 (2% CME, 98% Neat Diesel), B5 (5% CME, 95% Neat Diesel), B10 (10% CME, 90% Neat Diesel), B15 (15% CME, 85% Neat Diesel) and B20 (20% CME, 80% Neat Diesel) were used and their results is compared to B0 (Neat). This will also The tests were performed at the University of the Philippines Vehicle Research and Testing Laboratory at steady state conditions, a naturally aspirated water cooled four cylinder Common Rail Direct Injection Diesel (CRDi) engine, with varying speeds from 800 to 4000 RPM at an interval of 400 RPM while maintaining the throttle 100% wide open. As a result of the investigation at typical engine speed range (1200–2400 RPM) no significant differences for biodiesel blends vs. neat diesel were observed for torque, power, CO2 and NOx emissions. However, a decrease of HC and CO was observed. Meanwhile, at 2800–4000 RPM, an increase in torque, power, CO2 and NOx, but no significant differences in HC and CO emissions. However, the engine does not normally run at the higher speed range (1800–2400 RPM) for a long period of time. With respect to biodiesel blends, torque, power, CO2, and NOx emissions generally increase with increasing biodiesel blend, while CO and HC emissions generally decreased with increasing biodiesel blend.

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