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Urea-based selective catalytic reduction (SCR) of nitric oxides (NOx) is a key technology for heavy-duty diesel engines to achieve the increasingly stringent NOx emission standards. The aqueous urea injection control is critical for urea-SCR systems in order to achieve high NOx conversion efficiency while restricting the tailpipe ammonia (NH3) slip. For Euro VI emission regulation, an advanced control strategy is essential for SCR systems since its NOx emission limits are tighter and test procedure are more stringent compared to Euro IV and Euro V. The complex chemical kinetics of the SCR process has motivated model-based control design approaches. However, the model is too complex to allow real-time implementation. Therefore, it is very important to have a reduced order model for SCR control system.

This paper presents an introduction of a 4-zone phenomenological combustion model. By using this model, mass combustion rate and NOX emission may be deduced from measured indicator diagram of D.I. diesel engines. Based on the test data of type LD1100 diesel engine, the influence of combustion system parameters and running parameters on measured results are discussed in this paper. From a measured indicator diagram, the only result of combustion rate may be deduced, but the chosen values of some parameters influence the deduced result of NOx emission. The measured combustion rates by using phenomenological model are compared with that by using thermodynamic model. In this paper, authors discuss the influence between that two combustion rates, and point out that former combustion rate more conform to the actual combustion process.

The experiments were made on the direct injection combustion system consisting of the shallow W - type combustion chamber and the intake port with shorter passage length and weaker swirl intensity, which leads to lower requirements for manufacturing the engine cylinder head, in a small bore single - cylinder diesel engine. Test results are satisfactory. Based on performence characteristics and heat release rate curves measured in different behaviour under various matches of combustion chamber design and fuel injection system, authors have discussed each effect of design parameters on engine performances and combustion characteristics, and put forward the key points for optimization of the combustion system match.

The authors of this paper investigated the influences of fuel supply timing delay on fuel consumption maxmum combustion pressure, NOx emission and smoke of two diesel engines with shallow type combustion system Based on measured, indicator diagram, combustion rate and NOx emission were predicted by using phenomenological combustion model. Furthermore, theoritical of the test result were made.