Diesel engine is acknowledged for its superior efficiency and possesses a wide field of applications. It is also known as CI engine. Diesel engines also however, are the prime source of emissions such as NOX and particulate matter (PM). In order to reduce the emissions to an absolute minimum, this book explain as to how these toxins can be regulated. It is no hidden secret that the world is witnessing an oil crisis. But with other alternative sources such as biogas, natural gas and coke based substances; diesel is not the only way forward. The unique characteristics and properties such as combustion and emission of the aforementioned alternatives are explained extensively in this book. The book also goes on to explain how one can look for early signs of wear and tear and malfunctioning components of a diesel engine and its parts.