Combustion Optimisation of 2.5 l Direct Injection Diesel Engine to Meet Bharat Stage-III Emission Norms 2005-26-005
In today's continuously increasing stringency of emission legislations in India such as Bharat Stage-II (BS-II) and Bharat Stage-III (BS-III). The customer's expectations of vehicle performance, such as serviceability, reliability, comforts etc., and it is imperative for vehicle manufacturers to replace the existing old technology engines or upgrade them with new advanced technologies such as turbo-charging, electronically controlled fuel injection systems, Exhaust Gas Recirculation (EGR), exhaust system with after-treatment etc. These advanced electronically controlled systems have some drawbacks like special training required to understand electronic systems, difficulties in servicing or repairing components, poor reliability and cost.
In this paper, a cost effective solution was discussed to meet BS-III emission norms of existing 2.5 L direct injection diesel engine with upgradation by turbocharging, optimisation of combustion and other related subsystems, such as mechanical rotary Fuel Injection Equipment (FIE), electronically controlled cooled EGR and oxidation catalyst. BS-III Emission norms were achieved without any cold advance system in FIE and without inter-cooler for charged air. Because of this it becomes a cost-effective solution
A three-stage process was used for upgradation and optimisation of combustion of the engine. In the first stage, upgradation of engine performance by turbocharging was done on engine dynamometer. In the second stage, specific emission optimisation was done on engine dynamometer using thirteen simulated key points derived from EEC and European Driving Cycle (EUDC) chassis dynamometer cycle. Different parameters like piston bowl, turbocharger, injector, cam rate, and Injection timing etc. were evaluated for emission and smoke at these key points. In the third stage, optimisation of emission on chassis dynamometer with electronically controlled EGR was done.