Browse Publications Technical Papers 2018-01-0936

The Effect of Gasoline Metallic Additives on Low Speed Pre-Ignition 2018-01-0936

Methylcyclopentadienyl manganese tricarbonyl (MMT) is used as an octane-enhancing metallic additive for unleaded gasoline which can prevent engine knock by proactive reaction with the hydrocarbon free radicals before starting the auto-ignition of hydrocarbons. However it has been pointed out that MMT causes automotive catalysts clogging and spark plug severely fouling. Therefore, many countries have fuel standards that prohibit or limit the usage of MMT. Nevertheless, some countries still use MMT as there are no restrictions imposed by fuel standards. As mentioned in several papers, metallic additives of engine oil such as calcium cause an abnormal combustion phenomenon called low-speed pre-ignition (LSPI) in turbocharged spark ignition engines. In contrast, the effect of metallic additives of gasoline such as MMT on LSPI has not been studied. In this study, it was confirmed that manganese in gasoline increased the possibility of LSPI, and that lower volatile gasoline which contains heavy aromatic components tended to show higher sensitivity to manganese concentration in turbocharged spark ignition engines. These analyses also showed that the amounts of deposits containing manganese increased in the combustion chamber. In addition, it was observed that several particles became glowing in the combustion chamber and became the starting point of LSPI. With regard to the mechanism underlying the phenomenon, it is supposed that the heat of reaction produced by the oxidizing MMT in gasoline droplets or deposits containing manganese form the ignition source and increase the possibility of LSPI.


Subscribers can view annotate, and download all of SAE's content. Learn More »


Members save up to 18% off list price.
Login to see discount.
Special Offer: Download multiple Technical Papers each year? TechSelect is a cost-effective subscription option to select and download 12-100 full-text Technical Papers per year. Find more information here.
We also recommend:

Real Fuel Effects on Low Speed Pre-Ignition


View Details


Low Speed Pre-Ignition (LSPI) Durability – A Study of LSPI in Fresh and Aged Engine Oils


View Details


Investigations on the Influence of Fuel Oil Film Interaction on Pre-ignition Events in Highly Boosted DI Gasoline Engines


View Details