چكيده به لاتين
Low-temperature combustion (LTC) has been demonstrated that has ability to reduce the Nox and PM emissions in-cylinder while maintaining high thermal efficiency. Due to its results, many attention has been attracted to it. Many of the advanced combustion strategies can be classified as LTC is characterized by approaches of introducing fuels in the cylinder.
In recent years, proposing use of two fuel with different ignition characteristics and by injecting fuel with low reactivity in intake stroke and with high reactivity in compression stroke, led to introduce reactivity controlled compression ignition (RCCI) strategy. However, controlling of parameters of combustion under LTC conditions in a consistent manner has proven to be difficult. In order to have more controllability in term of combustion parameters, this research conducting open and closed-cycle simulations on a heavy-duty engine fueled two different fuels (diesel and gasoline fuels) by introducing direct injection of both of them, using Converge CFD software.
The results have been shown that reactivity fuel has a significant role. By increasing the level of stratifying low reactivity fuel, the sensitivity of combustion parameters was increased. Close to top dead center (TDC), this injection provides long duration combustion that represents controllability on combustion phase. Therefore, by direct injecting two fuels, it is possible to gain a new level of control over the shape and stability of the combustion event, along with the ability to combine characteristic of RCCI and Stratified strategies.
Comparison of the open and close cycle of the engine with two direct injected fuels has been shown that the assumptions of homogeneous premixed fuel and turbulent kinetic energy at intake valve close (IVC) is a true and a wrong assumption, respectively.
