Current Status and Future Strategies of Gas Engine Development
The present paper describes the current development status of high speed (with nominal speeds of 1200 to 1800 rpm) and medium speed (with nominal speeds up to 1000 rpm) large gas engines as well as their future development strategies for the short to middle term. The population of natural gas engines for stationary applications such as power generation or gas compression has expanded significantly in the last few decades. Growing attention to the reduction of CO2 emission as well as upcoming more and more stringent regulations for NOx emission will make gas engines attractive also to marine and locomotive applications. In order to boost a long term growth trend of gas engines, further improvement in power density and thermal efficiency is demanded. Gas engines today have already reached competitive BMEP levels and comparable or even higher thermal efficiency levels compared to those of diesel engines. Gas engines owe such improvements greatly to the lean burn combustion principle, the Miller valve timing and incremental combustion developments such as optimization of combustion chamber geometries, increase of compression ratio and etc. Performance development of gas engine has been a struggle against knocking combustion all the time. In order to further increase the BMEP and/or thermal efficiency, knock resistance is yet to be improved. Miller cycle in conjunction with the charge air cooling suppresses the onset of knocking by reducing the combustion temperature. However, it raises requirement for the higher intake manifold pressure. As the compressor pressure ratio of a singlestage turbocharger is limited, even more aggressive Miller timing than today requires an application of twostage turbocharging. Another important aspect is the peak firing pressure capability of the engine platform. Considering that many of the gas engines currently in the market started their history with the BMEP of 10 to 12 bar and reached 20 to 22 bar up to now, they may be already close to their peak firing pressure limit. A further increase of the BMEP would impose a massive design change or even a new engine development. Based on experiences of gas engine developments with AVL proprietary single cylinder engine as well as with AVL proprietary simulation codes, the present reports reviews key technologies of gas engines and their current development status and discusses their limitations, potentials and requirements for the future gas engines. The most important key technologies that enable future development of gas engines are the application of even more aggressive Miller timing in conjunction with two stage turbocharging as well as the peak firing pressure capability of up to 250 bar and above.
Shinsuke Murakami Torsten Baufeld
AVL List GmbH,Austria
国际会议
上海
英文
1-15
2013-05-13（万方平台首次上网日期，不代表论文的发表时间）