Determination and control of engine phases

In at least some embodiments, a method of controlling a spark event in an engine includes determining at least one characteristic of a primary coil voltage of the spark event for at least two engine turns in a four-stroke engine; determining which of the spark events is associated with a compression phase of engine operation and which of the spark events is associated with an exhaust phase of engine operation based on a characteristic of the primary coil voltage; and providing a spark event in a subsequent engine turn associated with a compression phase of engine operation, but not in a turn associated with an exhaust phase of engine operation. In at least some embodiments, the feature is a duration of the spark event as determined by a change in the primary coil voltage, and the feature may be a duration of the primary coil voltage above a threshold voltage. 在至少一些实施方式中，一种控制发动机中的火花事件的方法包括：对于四冲程发动机中的至少两个发动机转圈，来确定火花事件的初级线圈电压的至少一个特征；基于初级线圈电压的特征来确定火花事件中的哪一个与发动机操作的压缩阶段相关联以及火花事件中的哪一个与发动机操作的排气阶段相关联；以及在与发动机操作的压缩阶段相关联