Search Results

Fuel formulation for premixed charge compression ignition (PCCI) combustion has been attempted based on the mixture formation and auto-ignition behavior of normal paraffin fuels. Different pure and mixed fuels with different blending ratios are tested. The mixture formation behavior is investigated photographically in a constant volume combustion chamber (CVCC) at elevated temperature and pressure. Auto-ignition behavior is tested in a Fuel Ignition Analyzer under different test conditions. It is found that the evaporation rate of pure n-paraffin fuel increases and the ignition delay becomes longer with decreases in the chain length. In the range of test condition used in this study, the flash-boiling phenomenon affects the fuel evaporation rate and ignition delay to some extent. Based on the experimental results a mixture of a very light mixture promoting component (MPC) and a moderately dense igniting component (IC) at a ratio of 3:1 is found to be optimum for PCCI combustion.

An experimental study was performed to investigate diesel particulate filter (DPF) performance during filtration with the use of real-time measurement equipment. Three operating conditions of a single-cylinder 2.3-liter D.I. heavy-duty diesel engine were selected to generate distinct types of diesel particulate matter (PM) in terms of chemical composition, concentration, and size distribution. Four substrates, with a range of geometric and physical parameters, were studied to observe the effect on filtration characteristics. Real-time filtration performance indicators such as pressure drop and filtration efficiency were investigated using real-time PM size distribution and a mass analyzer. Types of filtration efficiency included: mass-based, number-based, and fractional (based on particle diameter). In addition, time integrated measurements were taken with a Rupprecht & Patashnick Tapered Element Oscillating Microbalance (TEOM), Teflon and quartz filters.

The applicability of several popular diesel particulate matter (PM) measurement techniques to low temperature combustion is examined. The instruments' performance in measuring low levels of PM from advanced diesel combustion is evaluated. Preliminary emissions optimization of a high-speed light-duty diesel engine was performed for two conventional and two advanced low temperature combustion engine cases. A low PM (<0.2 g/kg_fuel) and NOx (<0.07 g/kg_fuel) advanced low temperature combustion (LTC) condition with high levels of exhaust gas recirculation (EGR) and early injection timing was chosen as a baseline. The three other cases were selected by varying engine load, injection timing, injection pressure, and EGR mass fraction. All engine conditions were run with ultra-low sulfur diesel fuel. An extensive characterization of PM from these engine operating conditions is presented.