Mixed Thermal Elastohydrodynamic Lubrication Analysis for the Coupled Cam-roller-pin Contact in Heavy-duty Marine Engines

The cam-roller-pin pair is the key component of fuel injectors in high-power marine engines, which supports the extremely high fuel pressure from the injector, leading to possible roller slip and severe surface wear. To analyze the performance of this friction pair, a mixed thermo-elastohydrodynamic lubrication model considering the coupling effects of the cam-roller-pin under heavy-duty operating conditions of marine engines is developed. The results show that the high fuel pressure from the injector significantly reduces oil film thickness and increases asperity contact and the coupling effects among the cam-roller-pin could cause roller slip. The friction loss in the cam-roller follower unit is primarily attributed to the roller-pin contact, and the temperature rise in this contact is also more significant. The influences of pin profile modification on friction reduction and wear reduction are also investigated, and the modified profile design resulted in a reduction of approximately 7.2%in friction loss and 12.8% in wear load. Additionally, the comparison between experimental and simulation results shows that the model is valid and the predicted results are reasonable.