Inter-laboratory correlation exercise on a light-duty diesel passenger vehicle to verify nano-particle emission characteristics by Korea particle measurement program

The Light Duty Inter-Laboratory Correlation Exercise (ILCE) final report, performed with the ‘PMP Golden Vehicle’ at nine laboratories in the EU, Korea and Japan to demonstrate repeatability and reproducibility of the particle number concentration emissions measurement techniques proposed by the Particle Measurement Program (PMP), was released in 2007. The ILCE was conducted by the Korea Particle Measurement Program (KPMP) with a domestic diesel passenger vehicle equipped with a diesel particulate filter (DPF) between three certification laboratories and the research center of an automotive manufacturer to meet future regulations (EURO 5 and EURO 6) of particle number concentration for light-duty vehicles in early 2008. This research focused on measuring the particulate matter emission (particle number and mass) levels of a representative light-duty diesel passenger vehicle during new European driving cycle (NEDC) mode to analyze the repeatability and reproducibility between laboratories in Korea. From the ILCE test results in Korea, the mean total particle number concentration levels ranged from 5.43E+10 #/km to 1.58E+11 #/km and 0.0003 g/km to 0.0036 g/km for particle mass. Repeatability between participating laboratories ranged from 32% to 66% for particle number, 11% to 70% for particle mass; the reproducibility level was 46% for particle number, and 66% for particle mass emission. This paper was recommended for publication in revised form by Associate Editor Kyoung Doug Min Simsoo Park received his B.S. and M.S. degrees from Seoul National University in 1997 and 1979, respectively, and a Ph.D. from the State University of New York at Stony Brook. He served as a Chief Research Engineer at Hyundai Motor Company, a Director for Publication of the KSME, a Technical Advisor of Hyundai-Kia Motor Company, and an Editing Director, Project Director, International Director, Accounting Director, and General Affair Director of KSAE. He is currently Vice President and of Editor-in-Chief of IJAT at KSAE and a professor in school of mechanical engineering at Korea University.     

The effect of exhaust gas recirculation (EGR) on combustion stability, engine performance and exhaust emissions in a gasoline engine

The EGR system has been widely used to reduce nitrogen oxides (NOx) emission, to improve fuel economy and suppress knock by using the characteristics of charge dilution. However, as the EGR rate at a given engine operating condition increases, the combustion instability increases. The combustion instability increases cyclic variations resulting in the deterioration of engine performance and emissions. Therefore, the optimum EGR rate should be carefully determined in order to obtain the better engine performance and emissions. An experimental study has been performed to investigate the effects of EGR on combustion stability, engine performance, NOx and the other exhaust emissions from 1. 5 liter gasoline engine. Operating conditions are selected from the test result of the high speed and high acceleration region of SFTP mode which generates more NOx and needs higher engine speed compared to FTP-75 (Federal Test Procedure) mode. Engine power, fuel consumption and exhaust emissions are measured with various EGR rate. Combustion stability is analyzed by examining the variation of indicated mean effective pressure (COV_imep) and the timings of maximum pressure (P_max) location using pressure sensor. Engine performance is analyzed by investigating engine power and maximum cylinder pressure and brake specific fuel consumption (BSFC).     

Sensitivity of hot film flow meter in four stroke gasoline engine

The air fuel ratios of current gasoline engines are almost controlled by several air flow meters. When CVVT (Continuous Variable Valve Timing) is applied to a gasoline engine for higher engine performance, the MAP (Manifold Absolute Pressure) sensor is difficult to follow the instantaneous air fuel ratio due to the valve timing effect. Therefore, a HFM (Hot Film Flow Meter) is widely used for measuring intake air flow in this case. However, the HFMs are incapable of indicating to reverse flow, the oscillation of intake air flow has an negative effect on the precision of the HFM. Consequently, the various duct configurations in front of the air flow sensor affect the precision of HFM sensitivity. This paper mainly focused on the analysis of the reverse flow, flow fluctuation in throttle upstream and the geometry of intake system which influence the HFM measurement.     

Experimental investigation of nanoparticle formation characteristics from advanced gasoline and diesel fueled light duty vehicles under different certification driving modes

This paper mainly focused on the comparison of nanoparticle size distribution and number concentration level characteristics with gasoline and diesel fueled light duty vehicles. In the engine research, particle size distribution and number concentrations were analyzed by a DMS500 with engine parameters. Time-resolved particle number concentration levels from test vehicles were measured by a golden particle measurement system (GPMS) as recommended by a Particle Measurement Programme (PMP) on certification modes such as New European Driving Cycle (NEDC), Federal Test Procedure (FTP)-75, and Highway Fuel Economy Test (HWFET). In addition, particle emission characteristics from vehicles were analyzed by DMS500 during transient and high-speed driving conditions. From the results, we found that the formation of particles was highly dependent on vehicle speed and load conditions for each mode. The diesel vehicle equipped with a particulate filter showed substantial reduction of the total particle number whose number concentration was equivalent to that of the gasoline vehicle. The nucleation mode particles from gasoline fuel were mainly emitted; however, the accumulation mode particles from the diesel fuel were generally analyzed. This paper was recommended for publication in revised form by Associate Editor Kyoung Doug Min Simsoo Park received his B.S. and M.S. degrees from Seoul National University in 1977 and 1979, respectively, and a Ph.D. from the State University of New York at Stony Brook. He served as a Chief Research Engineer at Hyundai Motor Company, a Director for Publication of the KSME, a Technical Advisor of Hyundai-Kia Motor Company, and an Editing Director, Project Director, International Director, Accounting Director, and General Affair Director of KSAE. He is currently Vice President and Editor-in-Chief of IJAT at KSAE and a professor in school of mechanical engineering at Korea University. Hyungmin Lee received his B.S. degrees from Republic of Korea Naval Academy in 1997 and his M.S. degrees from Korea University in 2005, respectively. He served as an Operation Officer, Command Engineer Officer at various naval vessels. He is currently Ph.D. course in school of mechanical engineering at Korea University and his rank is a Lieutenant Commander of Korea Navy.     

Effects of gas composition on the performance and emissions of compressed natural gas engines

Natural gas is considered to be a promising alternative fuel for passenger cars, truck transportation and stationary engines providing positive effects both on the environment and energy security. However, since the composition of natural gas fuel varies with location, climate and other factors, it is anticipated that such changes in fuel properties will affect emission characteristics and performance of CNG (Compressed Natural Gas) engines. The purpose of the present study is to investigate the effects of the difference in gas composition on the engine performance and emission characteristics, The results show that THC (Total Hydrocarbon) decreases with increasing WI (Wobbe Index) and MCP (Maximum Combustion Potential). On the other hand, it is observed that NOx slightly increases as WI and MCP increase. The TLHV (Total Lower Heating Value of Intake) is proposed in this study as a potential index for compatibility of gas fuels in a CNG engine. There is a variation in power up to 20% depending on the composition of gas when the A/F ratio and spark timing are fixed for a specific gas fuel.     

Effect of engine control parameters on combustion and particle number emission characteristics from a SIDI engine fueled with gasoline-ethanol blends

Journal of Mechanical Science and Technology - In this study, the impact of engine control parameters on combustion behaviors and particle number emissions was investigated with a spark ignition...     

Specific engine performance and gaseous emissions characteristics of European test cycle and worldwide harmonized driving cycle for a heavy-duty diesel engine

This study compares the engine operating behavior and regulated gaseous emissions characteristics between the reference European cycles (ESC/ETC) and the worldwide harmonized driving cycles (WHSC/WHTC), which will be applied in the Euro VI heavy-duty diesel engine emissions regulations, for the diesel particulate filter (DPF) equipped Mercedes 12 L diesel engine. The speed and load distribution for two additional representative harmonized cycles which cover a more realistic operating range for a heavy duty engine were established to verify the engine performance over wide range of the cycle work, fuel consumption, and exhaust system temperature as well as engine coolant temperature for repeated validation tests. The WHTC, including an additional test with cold start and transient operation before the hot start, had a substantial influence on the THC, CO, NOx, and PM exhaust emissions levels because of the engine heat-up time and temperature rising characteristics of aftertreatment device. Moreover, the different engine operating conditions of the WHSC influenced on the specific engine performance and gaseous emissions behavior unlike those of the ESC. Finally, the statistical analysis results through repeated tests validated the stationary and transient cycles running at the fully warm-up condition, however, those of WHTC were closely dependent on the inclusion of cold start condition or aggressive acceleration gradient of engine speed and load trace.     

Characterization of engine oil additive packages on diesel particulate emissions

This study investigated the impact of engine oil formulation on particulate matter (PM) characteristics from a light-duty diesel engine. The test engine was a 1.6 L Euro-5 diesel engine operated from low- to high-speed and high-load conditions. Specially formulated nonadditive containing base oil and genuine oil were evaluated. For diesel PM characterization, physicochemical analytic procedures were conducted on engine oil formulation, oil flushing, PMs sampling, morphology, and particle constituent determination. Size-resolved particle number (PN) concentration at the engine-out position was evaluated by differential mobility spectrometer (DMS). Nucleation mode particles originating from engine oil consumption during the expansion stroke had a higher concentration from genuine oil than those from base oil. Scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) were used to analyze the morphology patterns and atomic compositions with engine oil packages. From the SEM analysis, spherical PM of nucleation and accumulation mode particles were agglomerated on a quartz filter. In the XPS spectrum, more engine oil additive fractions of Ca, P, and Zn were found in the PM sample from genuine oil. In conclusion, the variation of physicochemical engine oil properties and additive amounts had strong contributions to engine oil derived PN emissions, morphology, and additive metal compositions in the exhaust gas stream.

     

Effects of various intake valve timings and spark timings on combustion,cyclic THC and NOX emissions during cold start phase with idle operation in CVVT engine

In a gasoline SI engine, valve events and spark timings put forth a major influence on overall efficiency, fuel economy, and exhaust emissions. Residual gases controlled by the valve overlap can be used to reduce NOx emissions and the spark retardation technique can be used to improve raw THC emissions and catalyst light-off performance during the cold start phase. This paper investigated the behaviors of the engine and its combustion characteristics with various intake valve timings and spark timings during the fast idle condition and cold start. And cyclic THC and NOx emissions were measured at the exhaust port and their formation mechanisms were examined with fast response gas analyzers. As a result, THCs and NOx were reduced by 35% and 23% with optimizing valve overlap and spark advance during the cold transient start phase. Consequently, the valve events and ignition timings were found to significantly affect combustion phenomena and cold-start emissions. This paper was recommended for publication in revised form by Associate Editor Kyoung Doug Min Simsoo Park received his B.S. and M.S. degrees from Seoul National University in 1977 and 1979, respectively, and a Ph.D. from the State University of New York at Stony Brook. He served as a Principle Research Engineer at Hyundai Motor Company, a Director for Publication of the KSME, a Technical Advisor of Hyundai-Kia Motor Company, and an Editing Director, Project Director, International Director, Accounting Director, and General Affair Director of KSAE. He is currently Vice President of Editing and International at KSAE and a professor of mechanical engineering at Korea University.     

Predictions of heat transfer and pressure drop for a modified power law fluid flow in a square duct

Numerical Solutions for the Nusselt Numbers (CHF and CWT) and the Friction Factor times Reynolds Number have been obtained for fully developed laminar flow of a MPL (Modified Power Law) fluid within a square duct. The solutions are applicable to pseudoplastic fluids over a wide shear rate range from Newtonian at low shear rates through a transition region to power law behavior at higher shear rates. A shear rate parameter is identified, which allows the prediction of the shear rate range for a specified set of operating conditions. Numerical results of the Nusselt numbers (CHF and CWT) and the Friction factors times Reynolds number for the Newtonian and power law regions are compared with previous published results, showing agreement with 0.02% in Newtonian region and 4.0% in power law region.