Complex sentence: This is done by timing the injection event such that the combustible mixture has a wider range of air/fuel ratios at the point of ignition, thus ignition occurs in different regions of the combustion chamber at different times-slowing the heat release rate.
Split into simpler sentences: This is done by timing the injection event such that a range of air/fuel ratios spread across the combustion cylinder when ignition begins. Ignition occurs in different regions of the combustion chamber at different times-slowing the heat release rate.