Ignition Characteristics of Diesel and Canola Biodiesel Sprays in the Low-Temperature Combustion Regime

Abstract

The objective of this work is to investigate the spray ignition characteristics of diesel and canola-derived biodiesel in a rapid compression machine at the low temperatures (676–816 K) and reduced oxygen concentrations (12 and 18%) that are used in low-temperature combustion strategies of advanced diesel engines. A method for testing ignition delay times and apparent heat release rates at a series of temperatures is developed and characterized, whereby a given temperature is attained prior to the fuel spray by altering the charge cooling time after the end of compression. A single-zone heat release model is formulated and used with the experimental pressure data to calculate two unique ignition delay periods. For diesel, the total ignition delays measured with this approach are found to correlate very well with diesel ignition delay data published in the literature. When the first ignition delay period is compared, which approximates the initial time of heat release after the start of injection, it is no...