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Internal combustion (IC) engines that meet Tier 4 Final emissions standards comprise of multiple engine operation and control parameters that are essential to achieve the low levels of NOx and soot emissions. Given the numerous degrees of freedom and the tight cost/time constraints related to the test bench, application of virtual engineering to IC engine development and emissions reduction programmes is increasingly gaining interest. In particular, system level simulations that account for multiple cycle simulations, incylinder turbulence, and chemical kinetics enable the analysis of combustion characteristics and emissions, i.e. beyond the conventional scope of focusing on engine performance only. Such a physico-chemical model can then be used to develop Electronic Control Unit in order to optimise the powertrain control strategy and/or the engine design parameters.

The characteristics of soot particles in an exhaust gas for low temperature diesel combustion (LTC) compared with conventional combustion in a compression ignition engine were experimentally investigated by the elemental and thermogravimetric analysis (TGA). Morphology of soot particles was also studied by the transmission electron microscopy (TEM). From the result of the TGA, the water can be evaporated until about 150°C for both combustion regimes. The soot particles for LTC contained more volatile hydrocarbons, which can be easily evaporated from 200°C to 420°C compared with conventional diesel combustion. The soot oxidation for conventional combustion occurs up to 600°C, on the other hand the particles for LTC is oxidized below 520°C. Elemental analysis showed higher oxygen weight fraction resulted from the oxygenated hydrocarbon for the soot particles in LTC. TEM has shown primary particles to be in a diameter range of 20 to 50 nm for conventional diesel combustion.

In marine or stationary engines, consistent engine performance must be guaranteed for long-haul operations. A dual-fuel combustion strategy was used to reduce the emissions of particulates and nitrogen oxides in marine engines. However, in this case, the combustion stability was highly affected by environmental factors. To ensure consistent engine performance, the in-cylinder pressure measured by piezoelectric pressure sensors is generally measured to analyze combustion characteristics. However, the vulnerability to thermal drift and breakage of sensors leads to additional maintenance costs. Therefore, an indirect measurement via a reconstruction model of the in-cylinder pressure from engine block vibrations was developed. The in-cylinder pressure variation is directly related to the block vibration; however, numerous noise sources exist (such as, valve impact, piston slap, and air flowage).