Combustion noise radiation during dynamic diesel engine operation including effects of various biofuel blends: A review

The target of the present work is to review the literature regarding the fundamental aspects of combustion noise radiation during transient operation of naturally aspirated and turbocharged diesel engines. The most important mechanisms are analyzed based on the key attributes of dynamic conditions, primarily in the form of turbocharger lag and slow cylinder wall temperature response. The analysis focuses on acceleration but covers also the other two fundamental discrete transient schedules, namely cold starting and load increase. Only the combustion-related noise component is covered in this survey, i.e. the gas-flow or mechanical noise contributions are not taken into account. Particular emphasis is placed on biofuels effects, since these have gained increased attention in the recent years as very promising alternative fuels for the transportation sector.