Combustion Optimization of a Marine DI Diesel Engine

Enrico Mattarelli; Stefano Fontanesi; Carlo Rinaldini; Gerardo Valentino; Stefano Iannuzzi; Elena Severi; Valeri Golovitchev

doi:10.4271/2013-24-0020

Enhanced calibration strategies and innovative engine combustion technologies are required to meet the new limits on exhaust gas emissions enforced in the field of marine propulsion and on-board energy production.

The goal of the paper is to optimize the control parameters of a 4.2 dm³ unit displacement marine DI Diesel engine, in order to enhance the efficiency of the combustion system and reduce engine out emissions. The investigation is carried out by means of experimental tests and CFD simulations.

For a better control of the testing conditions, the experimental activity is performed on a single cylinder prototype, while the engine test bench is specifically designed to simulate different levels of boosting.

The numerical investigations are carried out using a set of different CFD tools: GT-Power for the engine cycle analysis, STAR-CD for the study of the in-cylinder flow, and a customized version of the KIVA-3V code for combustion. All the models are calibrated through the above mentioned experimental campaign.

Then, CFD simulations are applied to optimize the injection parameters and to explore the potential of the Miller combustion concept. It is found that the reduction of the charge temperature, ensuing the adoption of an early intake valve closing strategy, strongly affects combustion. With a proper valve actuation strategy, an increase of boost pressure and an optimized injection advance, a 40% reduction of NOx emissions can be obtained, along with a significant reduction of in-cylinder peak pressure, without penalizing fuel efficiency.

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Combustion Optimization of a Marine DI Diesel Engine 2013-24-0020

SAE MOBILUS