2.2.II. Auto-ignition Auto-ignition can be defined as the situation in which the fuel in a combustion chamber burns automatically without an external cause such as a spark plug, and this is due to the extremely high temperature and pressure inside the room. Additionally, the fuel inside the combustion chamber will not burn at the appropriate time and combustion cannot be as efficient as if it burned at the appropriate time. Therefore, this problem will have negative effects both from an economic and environmental point of view (Willard, 1997).2.2.III. Incomplete combustionThis situation usually occurs if there is a lake of air inside the combustion chamber or if the oxygen is poor. In this situation, carbon monoxide, carbon and water are produced. Additionally, this type of combustion will pose two problems: they will produce a toxic gas, carbon monoxide, and the fuel will not burn efficiently (Bbc.co.uk).,