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The objective of this work is to compare and contrast standard metrics that are used to quantify engine knock phenomena. Several methods found in the literature were investigated, and the fundamental bases for the methods were elucidated. A new knock onset metric was developed and compared to the commonly used threshold value exceeded metric. The standard knock intensity metrics were categorized based on the underlying signal (pressure, heat release), domain of analysis (time or frequency), and the calculation method (single-valued or integral). Each category was evaluated based on the fundamental advantages and disadvantages of that category. Single-value methods were found to be inadequate because they are prone to biases due to wave interference and beating. Heat release-based metrics were found to be redundant and be based on flawed assumptions.

Large-scale flows in internal combustion engines directly affect combustion duration and emissions production. These benefits are significant given increasingly stringent emissions and fuel economy requirements. Recent efforts by engine manufacturers to improve in-cylinder flows have focused on the design of specially shaped intake ports. Utility engine manufacturers are limited to simple intake port geometries to reduce the complexity of casting and cost of manufacturing. These constraints create unique flow physics in the engine cylinder in comparison to automotive engines. An experimental study of intake-generated flows was conducted in a four-stroke spark-ignition utility engine. Steady flow and in-cylinder flow measurements were made using three simple intake port geometries at three port orientations. Steady flow measurements were performed to characterize the swirl and tumble-generating capability of the intake ports.