【作者】

Morten Vejlgaard-Laursen

【摘要】

该论文已在芬兰赫尔辛基举行的第28届CIMAC大会上发表。论文的版权归CIMAC所有。The IMO Tier III legislation applicable from 1 January 2016 has forced engine designers to develop new engine technologies that require new comprehensive control strategies. MAN Diesel & Turbo has chosen a two-technology approach for its two-stroke engines, supplying both exhaust gas recirculation (EGR) and selective catalytic reduction (SCR) to the engine makers. Both systems will be controlled by the emission reduction control system (ERCS). While some features of the SCR and EGR solutions on large two-stroke engines are inspired by similar and well-known solutions from the car industry; other features have completely new challenges. Some of the challenges may be that the technology is placed upstream of the turbocharger, the sulphur-containing fuels used, the application of the technology on a two-stroke engine or a combination. The basic control principle for EGR is feedback control of scavenge O2. However, as O2 sensors have slow responses, model-based control is proposed for improved O2 control in transient operation. As EGR changes the smoke margin, the EGR rate must be taken into consideration especially during vessel acceleration; though with proper control, acceleration may even be improved on an EGR engine. Furthermore, as the recirculated gas is cleaned with water, the water requires proper control of pH. As SCR reactant dosing is similar to that of the car industry, the primary challenge on marine engines is to avoid formation of ABS in the reactor or boiler by the applied dosing strategy. From a thermodynamic perspective, when the SCR is placed upstream of the turbocharger, the heat capacity of the SCR heavily affects the energy balance and thus the airflow of the engine. This requires dedicated control, not least while engaging and heating the SCR with the exhaust gas. This paper presents details on the above challenges and solutions as well as presenting the basic operating and failure handling principles, the system layout and not least compliance in practice.

【会议名称】

第28届CIMAC会议

【会议地点】

芬兰 赫尔辛基

【下载次数】

3

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