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This paper investigates the effect of boost pressure and intake temperature on the auto-ignition of fuels with a wide range of properties. The fuels used in this investigation are ULSD (CN 45), FT-SPK (CN 61) and two blends of JP-8 (with CN 25 and 49). Detailed analysis of in-cylinder pressure and rate of heat release traces are made to correlate the effect of intake pressure and injection strategy on the events immediately following start of injection leading to combustion. A CFD model is applied to track the effect of intake pressure and injection strategy on the formation of different chemical species and study their role and contribution in the auto-ignition reactions. Results from a previous investigation on the effect of intake temperature on auto-ignition of these fuels are compared with the results of this investigation.

This paper presents a simplified piston ring assembly (PRA) friction model accounting for the piston ring pack and the piston skirt. The ring model considers both mixed and hydrodynamic lubrication; the skirt model considers hydrodynamic lubrication only. The Reynold's equation is used as a governing equation for the hydrodynamic regimes of both models. Simplified assumptions are used for the mixed lubrication in the ring model. The ring model generates unique Stribeck curves for a given ring's geometry; the skirt model generates generic relationships between the friction force and skirt geometry, piston speed, oil viscosity, and assumed boundary conditions. Ring starvation effects are introduced by varying the boundary conditions, as appropriate. The results of the models are compared to measurements made on a motored and fired single cylinder diesel engine; the theoretical calculations provide a reasonable estimate of the measured data.