Effect of pre-chamber fuel injection parameters and EGR on the combustion and emissions of a heavy-duty diesel engine

This numerical simulation investigated the impact of pre-chamber fuel injection timing, injection angle, and exhaust gas recirculation (EGR) on combustion and emissions in a heavy-duty diesel engine using a pre-chamber combustion system. The results illustrate that the pre-chamber combustion system exhibits the potential to enhance the indicated thermal efficiency (ITE) of a diesel engine, while specific pre-chamber configurations can concurrently lower both NOx and soot emissions. The optimized cases show that the sustained turbulence generated by the pre-chamber enhances the redistribution of the unburned mixtures in the cylinder. The sustained turbulence leads to a broader range of gas mixtures near the equivalence ratio(Phi) of 1, resulting in complete combustion and lower NOx and soot emissions. In the optimized pre-chamber combustion system (with pre-chamber injection timing (PIT) at 0 degrees CA ATDC and pre-chamber injection angle (PIA) at 54.5 degrees), introducing 3% EGR results in a reduction of 11.61% in NOx emissions and 9.97% in soot emissions compared with the baseline engine.