Influence of Diesel Engine Combustion Parameters on Primary Soot Particle Diameter

Abstract

Effects of engine operating parameters and fuel composition on both primary soot particle diameter and particle number size distribution in the exhaust of a direct-injected heavy-duty diesel engine were studied in detail. An electrostatic sampler was developed to deposit particles directly on transmission electron microscopy (TEM) grids. Using TEM, the projected area equivalent diameter of primary soot particles was determined. A scanning mobility particle sizer (SMPS) was used for the measurement of the particle number size distribution. Variations in the main engine operating parameters (fuel injection system, air management, and fuel properties) were made to investigate soot formation and oxidation processes. Primary soot particle diameters determined by TEM measurements ranged from 17.5 to 32.5 nm for the diesel fuel and from 24.1 to 27.2 nm for the water-diesel emulsion fuel depending on the engine settings. For constant fuel energy flow rate, the primary particle size from the water-diesel emulsion fuel was slightly larger than that from the diesel fuel. A reduction in primary soot particle diameter was registered when increasing the fuel injection pressure (IP) or advancing the start of injection (SOI). Larger primary soot particle diameters were measured while the engine was operating with exhaust gas recirculation (EGR). Heat release rate analysis of the combustion process revealed that the primary soot particle diameter decreased when the maximum flame temperature increased for the diesel fuel.

Investigation on Particulate Oxidation from a DI Diesel Engine Fueled with Three Fuels

“…(Color figure available online.) 2006), while higher injection pressure can induce an increased proportion of homogeneous combustion and a shorter duration of combustion, and hence the formation of smaller primary particles (Mathis et al 2005). Table 5 shows that the biodiesel primary particles have a smaller diameter, while Figure 2 shows that biodiesel particle aggregates have a smaller GMD.…”

Soot particulate size characterization in a heavy-duty diesel engine for different engine loads by laser-induced incandescence

“…The initial tem perature varied between 2200 K and 3800 K, probably as a result of variations in available laser intensity in the probe volume, due to beam profile and in-cylinder attenuation. However, the initial tem perature has been shown n ot to be very critical for the calculation of the particle sizes from the been plotted together with the standard error of rm defined as SE = r std (4) in which r std is the standard deviation of the N measurements. The values for r m were all found to fall in the range from 0.25 to 0.35 (correspond ing to a FW H M of the particle radius distribution of 10-35 nm, depending on the value of rm).…”

“…M ost studies on the effect of engine operating conditions on soot characteristics have focused on the exhaust gas (see e.g., M athis et al [4] for a recent example). Recently, K ock et al [5] pub lished a paper on particle size measurements with single-color Time-resolved laser-induced incan descence (TR-LII) within a light-duty, 2-stroke diesel engine.…”

Influence of Waste Cooking Oil Biodiesel on the Particulate Emissions and Particle Volatility of a DI Diesel Engine

“…3, biodiesel could reduce BSPM in all the size bins, while the MMD of biodiesel particles is less than those of the ULSD and LSD, which indicates that the biodiesel particles contain a larger proportion of smallsize particles and the reduction on particulate emission arises from the reduction of the large-size particles. The same reasons which cause a larger reduction of particulate emissions with biodiesel, compared with the two diesel fuels, also lead to a larger reduction in particle MMD (Mathis et al, 2005;Tsolakis, 2006). Moreover, the reduction in particulate mass concentration may also suppress particle coagulation and hence reduce the MMD.…”