Premixed compression ignition control for the piston engines

低温点火分类；“冷火焰主导区域”、“负温度系数区域”和“蓝色火焰主导区域”三个典型区域，将是预混压燃发动机点火提前/滞后的普遍判据。在点火前反应过程中，气缸装药中甲醛在冷焰产生组分、温度和压力条件下是抑制添加剂，在冷焰产生条件较差时是促进剂。添加的甲醛对原本属于冷焰优势区的着火事件是多余的，具有抑制作用。另一方面，人工添加的甲醛可能是火焰前反应的起点，导致最终的热点火属于蓝色火焰为主的区域，出现少量燃料过渡和低中间体，高温化学占主导地位。它缩短了预燃诱导期，对点火有促进作用。对天然气预混压燃发动机的冷启动进行了热塞式辅助启动试验。安装辉光塞和添加甲醛会提高负荷混合物的温度，从而导致压缩混合物的局部温度较高。火花点火升温操作将是一种替代的启动程序。

The low-temperature-ignition classification ; three typical regime, "cool-flame dominant regime, "negative-temperature-coefficient regime" and "blue-flame dominant regime" would be a universal advanced/retarded criterion on ignition of fuel/air mixtures with formaldehyde doping for the ignition timing control in the premixed-compression-ignition engines. The formaldehyde would be a suppressing additive under the cool-flame generating constituents, temperature and pressure conditions, and a promoting additive under the poor cool-flame generating conditions in the cylinder charge during the preflame reactions leading to the ignition. The added formaldehyde is superfluous to the ignition event originally belonging to the cool-flame dominant regime, which would give a suppressing effect. On the other hand, the artificially added formaldehyde could be a starting point of preflame reactions leading to the final hot ignition belonging to the blue-flame-dominant regime, where a few fuel transition and low intermediates appear, and where the high temperature chemistry dominates. It allows a short cut of the preflame induction period, in consequence, a promoting effect for the ignition.A glow-plug assisted procedure is examined for the cold start of the natural-gas premixed-compression-ignition engine engines. A glow plug installation and formaldehyde addition will raise the load mixture temperature, which will result in the higher local temperature of compressed mixture. Spark-ignition operation for temperature increase would be an alternative starting procedure.