Three-dimension design for combustion chamber system in high speed direct-injection engine using KIVA-3V code

摘要

To design new combustion chamber system for modern diesel engine three-dimension CFD (computational fluid dynamics) software (KIVA-3V) is used. To improve emission standard original combustion chamber structure (4JB1) is modified and the new one is got. The new combustion chamber structure can fit for modern high-speed CR (common rail) diesel engine and increase compression ratio from 16 to 18.2. Since the new 4JB1 shape of piston head is not on the axis of symmetry, 360° was modeled which corresponds x-offset 4mm and y-offset 1mm. Finally, schematic of the test bench configuration and new engine specification are showed. Emissions of the two combustion chamber system are compared based on 13 load conditions with different EGR (Exhaust Gas Recirculation). Besides, when engine speed is 2200r/min, cylinder pressures and the corresponding heat release rates with rail pressure (1200bar) and 30%EGR are compared with experimental data.