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Technical Paper

A Study of the Effect of a Catalyzed Particulate Filter on the Emissions from a Heavy-Duty Diesel Engine with EGR

2001-03-05
2001-01-0910
The effects of a catalyzed particulate filter (CPF) and Exhaust Gas Recirculation (EGR) on heavy-duty diesel engine emissions were studied in this research. EGR is used to reduce the NOx emissions but at the same time it can increase total particulate matter (TPM) emissions. CPF is technology available for retrofitting existing vehicles in the field to reduce the TPM emissions. A conventional low sulfur fuel (371 ppm S) was used in all the engine runs. Steady-state loading and regeneration experiments were performed with CPF I to determine its performance with respect to pressure drop and particulate mass characteristics at different engine operating conditions. From the dilution tunnel emission characterization results for CPF II, at Mode 11 condition (25% load - 311 Nm, 1800 rpm), the TPM, HC and vapor phase emissions (XOC) were decreased by 70%, 62% and 62% respectively downstream of the CPF II.
Technical Paper

The Effect of Fuel and Engine Design on Diesel Exhaust Particle Size Distributions

1996-02-01
960131
The objective of this research was to obtain diesel particle size distributions from a 1988 and a 1991 diesel engine using three different fuels and two exhaust control technologies (a ceramic particle trap and an oxidation catalytic converter). The particle size distributions from both engines were used to develop models to estimate the composition of the individual size particles. Nucleation theory of the H2O and H2SO4 vapor is used to predict when nuclei-mode particles will form in the dilution tunnel. Combining the theory with the experimental data, the conditions necessary in the dilution tunnel for particle formation are predicted. The paper also contains a discussion on the differences between the 1988 and 1991 engine's particle size distributions. The results indicated that nuclei mode particles (0.0075-0.046 μm) are formed in the dilution tunnel and consist of more than 80% H2O-H2SO4 particles when using the 1988 engine and 0.29 wt% sulfur fuel.
Technical Paper

Collection and Characterization of Particulate and Gaseous-Phase Hydrocarbons in Diesel Exhaust Modified by Ceramic Particulate Traps

1987-02-01
870254
Protocols for sampling and analysis of particulate and gaseous-phase diesel emissions were developed to characterize the chemical and biological effects of using ceramic traps as particulate control devices. A stainless-steel sampler was designed, constructed, and tested with XAD-2 sorbent for the collection of volatile organic compounds (VOC). Raw exhaust levels of TPM and SOF and mutagenicity of the SOF and VOC were all reduced when the traps were used. Hydrocarbon mass balances indicated that some hydrocarbons were not collected by the sampling system and that the proportions of collected SOF and VOC were altered by the use of the traps. SOF hydrocarbons appeared to be derived mainly from engine lubricating oil; VOC hydrocarbons were apparently fuel-derived. There was no apparent effect on SOF mutagenicity due to either sampling time or reexposure of particulate to exhaust gases.
Technical Paper

The Physical and Chemical Character of Diesel Particulate Emissions-Measurement Techniques and Fundamental Considerations

1978-02-01
780108
The techniques used to characterize the chemical and physical nature of particulates in diesel exhaust emissions are reviewed. The emphasis is on understanding the broader aspects of the fundamental nature of not only diesel particulates, but particulate systems in general. Consideration is given to the special nature of particulates which make them significant pollutants and to the relative place of the diesel in the formation of man-made particles. The underlying combustion processes leading to carbon and sulfur based particulates are reviewed. The important variables in steps of the combustion processes which lead to particulate formation are considered, as well as major fuel and engine factors. Collection methods are examined with examples given from current diesel dilution techniques. Probes, sampling lines, and instrumentation are considered.
Technical Paper

The Effect of Low Sulfur Fuel and a Ceramic Particle Filter on Diesel Exhaust Particle Size Distributions

1992-02-01
920566
Diesel exhaust particle size distributions were measured using an Electrical Aerosol Analyzer (EAA) with both conventional (0.31 wt. pet sulfur) and low sulfur fuel (0.01 wt pet sulfur) with and without a ceramic diesel particle filter (DPF). The engine used for this study was a 1988 heavy-duty diesel engine (Cummins LTA10-300) operated at EPA steady-state modes 9 and 11. The particle size distribution results indicated the typical bi-modal distribution; however, there were clear differences in the number of particles in each mode for all conditions. For the baseline conditions with no DPF, there was more than one order of magnitude greater number of particles in the nuclei mode for the conventional fuel as compared to the low sulfur fuel, while the accumulation modes for each fuel were nearly identical.
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