Computational and experimental study on TR combustion system of diesel

A new combustion system applied in the 135-type diesel engine-TR(Three-Rapidity), was modified from deep cave ω combustion chamber with an oriented arc in the middle of chamber wall, and perfectly fit to a nozzle with orifices in conic section plus orifice in the center. Three-dimensional numerical simulation was completed and compared between TR combustion system and original 135 diesel engine combustion system in 50% load by STAR-CD. The results show that in TR combustion system, fuel ignition location is near TDC, and premix combustion proportion increases. The oriented arc, contracted cave and centric spray contribute to enhancing air flow, making more reasonable fuel distribution and forming more homogeneous mixture. The usage of air in chamber is effectively increased and heat loss from the chamber wall is obviously decreased. The cold start performance of the engine is also improved. A performance test on TR combustion system was made on a 135-type diesel engine. The results demonstrate that TR has better exhaust smoke than the original engine. At the low and moderate load, NO_x emission of TR combustion system is less than the original system, but more in high load condition, which can be solved by delaying fuel spray timing. TR combustion has much potential to improve emission with less structural change of the original engine.