Cylinder peak pressure (pmax) over operating cycle of a high-power turbo-charged compression-ignition engine indicates its in-cylinder combustion behavior and also the level of mechanical load acting on its power assembly components. It is significantly important to understand how pmax with cylinder pressure (p) varies due to possible changes in engine design and operation input condition parameters. The input parameters considered in this paper include piston crank-angle position (θ), compression ratio (CR), amount of cycle burning heat (Q), injection/combustion duration (Δθ), and fuel injection/combustion-start timing (θs). Effects of the input parameters to pmax and θpmax which is the crank-angle position of pmax in engines of this type are analyzed, predicted and characterized. Results with the approaches to achieving those are presented. It is indicated from the results that the crank-angle position of combustion duration (Δθ) has a significant effect on θpmax for a given engine power density. As the position of Δθ varies, θpmax varies accordingly and can be determined. It is also indicated that as θs is sufficiently retarded from a position before the top dead center (TDC) to a point close to TDC, either before or after, in a large-bore high-power turbocharged engine, the trend of pmax variation would be reversed. This establishes the minimum value of pmax over the range of engine combustion-start timing variation. The results and indications are beneficial and usefully needed in adjusting the design and operation input condition parameters for achieving optimized balances between power-output capacity, fuel efficiency, exhaust emissions and mechanical/thermal loading of engines in this type.

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