Modelling for investigation of combustion and emission characteristics in a high-speed direct-injection diesel engine with light duty under various operating conditions

Abstract

A numerical study was conducted to investigate combustion and emission characteristics in a high-speed direct-injection engine with a common-rail injection system under various operating conditions. In order to analyse the combustion characteristics, several models were used in this study. They were the renormalization group k-e model, the hybrid Kelvin-Helmholtz (wave) and the Rayleigh-Taylor model, the shell auto-ignition model, and the laminar and turbulent characteristic timescale combustion model. The prediction of exhaust emissions was conducted using nitrogen oxide NO x formation with an extended Zel'dovich mechanism and Hiroyasu soot formation with the Nagle-Strickland-Constable oxidation model respectively. Experimental combustion and emission characteristics were compared with calculated results under various operating conditions, such as injection timing, injection pressure, fuel mass, and engine speed. The calculated results show similar patterns to the experimental results in the cylinder pressure and the rate of heat release. In the emissions characteristics, NO x emission decreased as injection timing was retarded and the NO x and soot amounts increased with the increase in the injected fuel mass. The calculated soot trends for various injection timings showed different patterns from the experimental trends as the injection timing were retarded.

Effect of Multiple Injection Strategies on Combustion and Emission Characteristics in a Diesel Engine

“…The combustion and emission characteristics were analyzed according to various multiple injection conditions by conducting calculations using the KIVA-3V code, which has been extensively used to simulate the combustion process and formation of emissions in an engine. , The Shell multi-step model proposed by Halstead et al was applied to analyze the autoignition phenomenon of the diesel spray in the cylinder, and this model was expressed according to the composition of the generic reactions for HC fuel and the generic species, such as radical, intermediate species, and branching agents. The combustion model was combined with the autoignition model to analyze the overall combustion phenomena in the diesel engine as suggested by Kong et al In this study, the switching temperature between the ignition and combustion models was set to 1100 K, and in the case of the local cell temperature being lower than 1100 K, the ignition model was activated for a low-temperature chemistry but the laminar and turbulent characteristic time scale model was used to simulate the high-temperature chemistry in the case where temperatures reached higher than 1100 K.…”

Fast NOx emission prediction methodology via one-dimensional engine performance tools in heavy-duty engines

“…Kim et al 6 studied combustion and emission characteristics of a DI engine under different operating conditions. For emission prediction, they used the extended Zeldovich mechanism.…”

Virtual battery electric vehicle development via 1D tools

“…Heavy-duty diesel engine performance development studies will continue within the next three decades. There is still hope to lower the diesel engine related emissions significantly, as it is stated in different studies: O ¨zgu¨l et al, 3 Aldawood et al, 4 Smallbone et al, 5 Kim et al, 6 and Warnatz et al 7 On the other hand, it can be easily anticipated that the strict fuel consumption reduction targets cannot be fulfilled by only developing conventional technologies. OEMs are currently focusing on creating a bundle of products, including conventional technologies and advanced ones such as electrification and alternative fuels.…”