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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.

Urea selective catalytic reduction (SCR) is a key technology for heavy-duty diesel engines to meet the increasingly stringent nitric oxides (NOx) emission limits of regulations. The urea water solution injection control is critical for urea SCR systems to achieve high NOx conversion efficiency while keeping the ammonia (NH3) slip at a required level. In general, an open loop control strategy is sufficient for SCR systems to satisfy Euro IV and Euro V NOx emission limits. However, for Euro VI emission regulation, advanced control strategy is essential for SCR systems due to its more tightened NOx emission limit and more severe test procedure compared to Euro IV and Euro V. This work proposed an approach to achieve model based closed loop control for SCR systems to meet the Euro VI NOx emission limits. A chemical kinetic model of the SCR catalyst was established and validated to estimate the ammonia storage in the SCR catalyst.

Butanol, which is a renewable biofuel, has been regarded as a promising alternative fuel for internal combustion engines. When blended with diesel and applied to pilot ignited natural gas engines, butanol has the capability to achieve lower emissions without sacrifice on thermal efficiency. However, high blend ratio of butanol is limited by its longer ignition delay caused by the higher latent heat and higher octane number, which restricts the improvement of emission characteristics. In this paper, the potential of increasing butanol blend ratio by adding hot exhaust gas recirculation (EGR) is investigated. 3D CFD model based on a detailed kinetic mechanism was built and validated by experimental results of natural gas engine ignited by diesel/butanol blends. The effects of hot EGR is then revealed by the simulation results of the combustion process, heat release traces and also the emissions under different diesel/butanol blend ratios.

Turbocharging industry mainly employ steady method in the design and development process in present. However, the unsteady method is becoming more important for the exploration of the advanced turbocharging technique. This paper discusses the influences of A/R value on unsteady performances of a double-entry turbocharger turbine. In the study, numerical simulation has been done by ANSYS CFX software, The turbine have three kinds of A/R values that change in order, and the three schemes has the same unsteady flow boundary conditions. The simulation results show that the unsteady turbine performances have the characteristics loops representing filling and emptying effects. And the unsteady performances of the three schemes have some regular differences. The mean unsteady turbine efficiency decreases with increasing A/R value in the involved range, but the overall entropy of the turbine in a pulse period has no significant differences.

This work presents a comprehensive computational study of diesel - natural gas (NG) dual fuel engine. A complete computational model is developed for the operation of a diesel - NG dual fuel engine modified from an AVL 5402 single cylinder diesel test engine. The model is based on the KIVA-3V program and includes customized sub-models. The model is validated against test cell measurements of both pure diesel and dual fuel operation. The effects of NG on ignition and combustion in dual fuel operation are analyzed in detail. Zero-dimensional computations with a diesel surrogate reaction mechanism are conducted to discover the effects of NG on ignition and combustion and to reveal the fundamental chemical mechanisms behind such effects. Backed by the detailed theoretical analysis, the engine operation parameters are optimized with genetic algorithm (GA) for the dual fuel operation of the modified AVL 5402 test engine.

Material creep action under the high temperature is a important factor which should be considered analyzing the pin boss durability. This paper studied the plastic action of the pin boss under the thermomechanical load. As a result, the plastic strain range is smaller than Besides, pin boss damage may be derived from the bigger silicon particle concentration and the bigger iron debris concentration. The enlarged particle deformation under the severe load would cause microfracture between the silicon particles and the aluminum-silicon phase until the part broken.

In this paper, a diesel particulate filter system which uses needle felt as filtering medium to collect diesel particulates has been developed and tested in practical operation of the urban bus. The system includes a bag filter, an exhaust cooler, and a control unit. It was installed under the chassis of a YZL 6730C diesel bus, which operates in a loop route mostly with heavy load. The bus has covered more than 5,000km, during which there was no failure of the filter system to cause bus abnormal operation. It needs to be cleaned for about 50km, and the collected particulate matter has to be discharged for every 1200km. It can operate reliably and easily with very high collection efficiency. The collected particulate matter is analyzed by GC (Gas Chromatography)/MS (Mass Spectrometer), it is found that the collected particulate matter contains many poisonous and carcinogen substances and the filter is also effective to collect some of the SOF.

A calculation model for high-speed electromagnet property of electronic-controlled fuel injection system of diesel engine has been formulated with considering of leakage of magnetic flux and resistance of core. The results have been proved by relational tests. The results of an M490F type high-speed electromagnet show that in order to acquire good controlling effect, the resistance of core should not be ignored except it is much bigger than the solenoid resistance.