【作者】

Christoph Mathey

【摘要】

论文已在中国上海举行的2013年CIMAC大会上发表。论文的版权归CIMAC所有。ABB Turbocharging presented the electro-hydraulic variable valve timing system VCM® during the 2010 CIMAC congress in Bergen. The VCM® has a considerable degree of flexibility, allowing it to be used on diesel and gas engines of different sizes and for different purposes. The system also has the inherent possibility to be customised in such a way that easy integration without major changes to an existing engine design is feasible. After extensive mechanical testing of the full system, including a validation and qualification programme on a small medium speed diesel engine, the possibility of the VCM® improving the performance of a gas engine has been investigated. On performance we found an improvement in fuel consumption and other engine parameters. The control unit in a conventional high speed pre-mix gas engine consists of a throttle valve and a compressor by pass. Both consume a substantial amount of energy as they provide a pressure reserve for acceleration and control purposes. One concept by which the performance of such an engine could improve is to substitute these control devices with variable inlet valve timing and lift, i.e. the application of VCM®.This paper shows the design of the VCM® unit for a high speed gas engine where the mechanical boundary conditions are discussed, how these could be fulfilled and how they are influencing the performance of the engine with regard to how the engine reacts to certain variations in the system. With regard to thermodynamic performance, the paper considers possible improvements brought by de-throttling and how the engine operates in normal conditions as well as during load changes. The application of skip-firing/ cylinder cut-off is also discussed. Furthermore, the paper looks at the required set-up of the inlet valve under changing ambient conditions as well as changing gas qualities and applications with variable engine speed.

【会议名称】

第27届CIMAC会议

【会议地点】

上海

【下载次数】

1

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