This study investigates the effects of intermediate temperature heat release (ITHR) on autoignition reactivity of full boiling range gasolines with different octane sensitivity through intake temperature and simulated exhaust gas recirculation (EGR) sweeps in a homogenous charge compression ignition (HCCI) engine. To isolate the ITHR effects, low temperature reactivity was suppressed through the use of high intake temperature and low intake oxygen mole fraction. For quantification of ITHR, a new method was applied to the engine data by examining the maximum value of the second derivative of heat release rate. Combustion phasing comparisons of fuels with octane sensitivity showed that fuel with less octane sensitivity became more reactive as intake temperature and simulated EGR ratio decreased, while fuel with higher octane sensitivity had a reverse trend. For all of the fuels that were tested, the amount of ITHR increased as the intake temperature and oxygen mole fraction increased. These ITHR trends, depending on octane sensitivity, were almost identical with the trends of combustion phasing, showing that ITHR significantly affects fuel autoignition reactivity and determines octane sensitivity.

这项研究通过均质充量压缩点火（HCCI）发动机，通过进气温度和模拟废气再循环（EGR）扫描，研究了中温放热（ITHR）对具有不同辛烷值敏感性的全沸程汽油的自燃反应性的影响。为了隔离ITHR的影响，通过使用高进气温度和低进气氧摩尔分数来抑制低温反应性。为了量化ITHR，通过检查放热率二阶导数的最大值，将一种新方法应用于发动机数据。辛烷值敏感性燃料的燃烧定相比较表明，辛烷值敏感性较低的燃料随着进气温度和模拟EGR率的降低而变得更具反应性，而具有更高辛烷值敏感性的燃料则呈现相反的趋势。对于所有测试的燃料，ITHR的量随进气温度和氧气摩尔分数的增加而增加。这些ITHR趋势取决于辛烷值敏感性，与燃烧定相的趋势几乎相同，表明ITHR显着影响燃料自燃反应性并确定辛烷值敏感性。