Lubricant-induced Low Speed Pre-Ignition (LSPI) Mechanism

Boosting, direct-injection, late combustion and low piston-ring tension all increase the propensity for
Low Speed Pre Ignition (LSPI), which can lead to destructive megaknock. Droplets of lubricant or particles of combusted lubricant are considered the source of LSPI. This I-Case PhD collaborated project between BP and Imperial College will aim to characterise and understand the physical and chemical properties of droplets/deposits. Experiment will be conducted in a combustion bomb, equipped with a mono-dispersed droplet generator. Parametric study by varying the physical and chemical properties of the droplets will be conducted with the objective to produce a ranking of all the lubricant components with regards to their LSPI performance. Another aspect of the project will investigate the reaction mechanism of metal based deposits. The outputs from the collaborated PhD project will provide insight on lubricant formulation to meet future stringent requirement from industry and OEMs.