A speed control analysis for an in-line gasoline fueled internal combustion （IC） engine is presented for the purpose of alleviation of high frequency oscillations in engine revolutions. A dynamic cylinder-by-cylinde...A speed control analysis for an in-line gasoline fueled internal combustion （IC） engine is presented for the purpose of alleviation of high frequency oscillations in engine revolutions. A dynamic cylinder-by-cylinder model is proposed, base on slider-crank mechanism, which is extended to develop a digital governor providing a high fidelity estimation of rotary speed oscillation for hybrid vehicle engines. A modified PID controller that P and I gain is placed in feedback path is also described for hybrid electric vehicle （HEV） engine speed regulation, By comparison between measured and estimated signals, it is demonstrated that a good agreement has been achieved and the governor behaves an excellent damping speed ripple.展开更多
A booming digital economy is reshaping China’s economic landscape as the spread of technology such as big data and atificial intelligence(AI)revives traditional industries and casts new light on high-quality developm...A booming digital economy is reshaping China’s economic landscape as the spread of technology such as big data and atificial intelligence(AI)revives traditional industries and casts new light on high-quality development.China’s digital economy amounted to22.58 trillion yuan($3.43 trillion)in 2016,ranking second globally and accounting for展开更多
Internet 已成为推动世界经济的强大动力。在美国Internet经济的总额1996年为155亿美元,1997年增加到390亿美元,预计到2001年将猛增至3500亿美元。所以本文作者认为Internet正在推动美国新经济(new economy)时代的到来,并指出与美国的...Internet 已成为推动世界经济的强大动力。在美国Internet经济的总额1996年为155亿美元,1997年增加到390亿美元,预计到2001年将猛增至3500亿美元。所以本文作者认为Internet正在推动美国新经济(new economy)时代的到来,并指出与美国的商业部门相比较,美国的政府和教育部门已在Internet经济中落后。尤其是教育。如在过去5年中美国有博士学位的工程师中的1/4来自国外。展开更多
Aircraft collaboration design is based on a unified set of schemas containing data and model representations and interfaces across disciplines.The aircraft design schema is a central data model that specifies the para...Aircraft collaboration design is based on a unified set of schemas containing data and model representations and interfaces across disciplines.The aircraft design schema is a central data model that specifies the paradigm for the representation of a full lifecycle model of aircraft design.The construction of the schema currently lacks theoretical guidance.This paper designs a novel methodology to construct the aircraft design schema,a fully functional,logical,and selfconsistent methodology.The methodology defines a schema matrix that includes implementation strategies,principles,processes,meta-object facility,views,scenarios,and products.The aircraft conceptual design schema is constructed according to the methodology,which is a hands-on approach to help understand the concept and implementation.The features of the methodology are analyzed,and the methodology and the aircraft conceptual design schema are presented to address the pain points of multiple solution trade-offs,multiple iterations,and multidisciplinary coupling in aircraft conceptual collaboration design.展开更多
基金This project is supported by National Hi-tech Research and Development Program of China(863 Program, No.2001AA501211).
文摘A speed control analysis for an in-line gasoline fueled internal combustion （IC） engine is presented for the purpose of alleviation of high frequency oscillations in engine revolutions. A dynamic cylinder-by-cylinder model is proposed, base on slider-crank mechanism, which is extended to develop a digital governor providing a high fidelity estimation of rotary speed oscillation for hybrid vehicle engines. A modified PID controller that P and I gain is placed in feedback path is also described for hybrid electric vehicle （HEV） engine speed regulation, By comparison between measured and estimated signals, it is demonstrated that a good agreement has been achieved and the governor behaves an excellent damping speed ripple.
文摘A booming digital economy is reshaping China’s economic landscape as the spread of technology such as big data and atificial intelligence(AI)revives traditional industries and casts new light on high-quality development.China’s digital economy amounted to22.58 trillion yuan($3.43 trillion)in 2016,ranking second globally and accounting for
文摘Aircraft collaboration design is based on a unified set of schemas containing data and model representations and interfaces across disciplines.The aircraft design schema is a central data model that specifies the paradigm for the representation of a full lifecycle model of aircraft design.The construction of the schema currently lacks theoretical guidance.This paper designs a novel methodology to construct the aircraft design schema,a fully functional,logical,and selfconsistent methodology.The methodology defines a schema matrix that includes implementation strategies,principles,processes,meta-object facility,views,scenarios,and products.The aircraft conceptual design schema is constructed according to the methodology,which is a hands-on approach to help understand the concept and implementation.The features of the methodology are analyzed,and the methodology and the aircraft conceptual design schema are presented to address the pain points of multiple solution trade-offs,multiple iterations,and multidisciplinary coupling in aircraft conceptual collaboration design.
