Greg Payne

Bio: Greg Payne is an academic researcher. The author has contributed to research in topics: Combustion & Particle size. The author has an hindex of 2, co-authored 3 publications receiving 83 citations.

Evaluation and Comparison of Portable Emissions Measurement Systems and Federal Reference Methods for Emissions from a Back-Up Generator and a Diesel Truck Operated on a Chassis Dynamometer

Abstract: There is considerable interest in portable emissions measurement systems (PEMS) for emission inventory and regulatory applications. For this study, four commercial PEMS were compared with a Federal Reference Method (FRM) for measuring emissions from a back-up generator (BUG) over steady-state loads and a diesel truck on transient and steady-state chassis dynamometer tests. The agreement between the PEMS and the FRM varied depending on the pollutant and the particular PEMS tested for both the BUG and chassis dynamometer testing. The best performing PEMS for both the BUG and chassis testing was within ∼12% for NOx of the FRM. For the BUG testing, several PEMS showed agreement with the FRM within ∼5% for CO2. For the chassis dynamometer testing, the best PEMS showed agreement typically within ∼5% for CO2. PM measurements for the BUG testing were low compared to the FRM, with the best measurements ∼20% lower. For the chassis testing, two PM PEMS showed a good correlation but a high bias, while the correlation...

Impact of Biofuel Blends on Black Carbon Emissions from a Gas Turbine Engine.

Abstract: Presented here is an overview of nonvolatile particulate matter (nvPM) emissions, i.e., “soot”, as assessed by TEM analyses of samples collected after the exhaust of a J-85 turbojet fueled with Jet-A as well as with blends of Jet-A and Camelina biofuel. A unifying explanation is provided to illustrate the combustion dynamics of biofuel and Jet-A fuel. The variations of primary particle size, aggregate size, and nanostructure are analyzed as a function of biofuel blend across a range of engine thrust levels. The postulate is based on where fuels start along the soot formation pathway. Increasing biofuel content lowers aromatic concentration while placing increasing dependence upon fuel pyrolysis reactions to form the requisite concentration of aromatics for particle inception and growth. The required “kinetic” time for pyrolysis reactions to produce benzene and multiring PAHs allows increased fuel–air mixing by turbulence, diluting the fuel-rich soot-forming regions, effectively lowering their equivalence ratio. With a lower precursor concentration, particle inception is slowed, the resulting concentration of primary particles is lowered, and smaller aggregates were measured. The lower equivalence ratio also results in smaller primary particles because of the lower concentration of growth species.

Experimental verification of principal losses in a regulatory particulate matter emissions sampling system for aircraft turbine engines

Abstract: A sampling system for measuring emissions of nonvolatile particulate matter (nvPM) from aircraft gas turbine engines has been developed to replace the use of smoke number and is used for internatio...

The challenge to NO x emission control for heavy-duty diesel vehicles in China

Abstract: . China's new "Twelfth Five-Year Plan" set a target for total NOx emission reduction of 10% for the period of 2011–2015. Heavy-duty diesel vehicles (HDDVs) have been considered a major contributor to NOx emissions in China. Beijing initiated a comprehensive vehicle test program in 2008. This program included a sub-task for measuring on-road emission profiles of hundreds of HDDVs using portable emission measurement systems (PEMS). The major finding is that neither the on-road distance-specific (g km−1) nor brake-specific (g kWh−1) NOx emission factors for diesel buses and heavy-duty diesel trucks improved in most cases as emission standards became more stringent. For example, the average NOx emission factors for Euro II, Euro III and Euro IV buses are 11.3 ± 3.3 g km−1, 12.5 ± 1.3 g km−1, and 11.8 ± 2.0 g km−1, respectively. No statistically significant difference in NOx emission factors was observed between Euro II and III buses. Even for Euro IV buses equipped with SCR systems, the NOx emission factors are similar to Euro III buses. The data regarding real-time engine performance of Euro IV buses suggest the engine certification cycles did not reflect their real-world operating conditions. These new on-road test results indicate that previous estimates of total NOx emissions for HDDV fleet may be significantly underestimated. The new estimate in total NOx emissions for the Beijing HDDV fleet in 2009 is 37.0 Gg, an increase of 45% compared to the previous study. Further, we estimate that the total NOx emissions for the national HDDV fleet in 2009 are approximately 4.0 Tg, higher by 1.0 Tg (equivalent to 18% of total NOx emissions for vehicle fleet in 2009) than that estimated in the official report. This would also result in 4% increase in estimation of national anthropogenic NOx emissions. More effective control measures (such as promotion of CNG buses and a new in-use compliance testing program) are urged to secure the goal of total NOx mitigation for the HDDV fleet in the future.

Characteristics of diesel truck emission in China based on portable emissions measurement systems.

Abstract: Seventy-five diesel vehicles were measured in China using a portable emissions measurement system (PEMS). Particular matter (PM) emission factors and gaseous emission factors for Euro 0 (E0), Euro 1 (E1), Euro 2 (E2), and Euro 3 (E3) trucks were obtained under highway, urban, and rural driving conditions. Vehicle emission regulations in China have successfully reduced carbon monoxide (CO), hydrocarbons (HC) and PM by 62, 56, and 72% on average. Most of the emission reductions were achieved when the control technology went from E0 to E1 in Xi’an, and E2 to E3 in Beijing, which resulted in PM reductions of 79% associated with highway driving and 60% associated with urban or rural driving. Emission levels of oxides of nitrogen (NOX) were not improved from previous emission control steps. Compared with Xi’an, the emission rate is lower in Beijing, which is strong evidence of the effectiveness of the present comprehensive emission control strategy in Beijing. Emissions were grouped into driving bins that corre...