For the purpose of engineering development for a new 8-step speed automatic transmission,a simplified dynamic model for this gearbox was established and key parameters which affected the shift quality were analyzed.Ai...For the purpose of engineering development for a new 8-step speed automatic transmission,a simplified dynamic model for this gearbox was established and key parameters which affected the shift quality were analyzed.Aiming at four different shift types,the ideal characteristics of shift clutch and engine control were set up.By using torque estimation method,PI slip control algorithm and engine coordinated control principle,the control model and transmission controller were well developed for three shift phases which included rapid-fill phase,torque phase and inertia phase.The testing environment on the rig and prototype vehicle level was built and the testing results obtained in ultimate condition could verify the accuracy and feasibility of this shift control strategy.The peak jerk during shift process was controlled within ±2 g/s where the smooth gearshift was obtained.The development proposal and algorithm have a high value for engineering application.展开更多
Till about 15 years ago, almost all information exchange among scientists and scholars was mediated by print and even then researchers in the developing countries were at a great disadvantage as their libraries did no...Till about 15 years ago, almost all information exchange among scientists and scholars was mediated by print and even then researchers in the developing countries were at a great disadvantage as their libraries did not have the resources to subscribe in comparison with even a small fraction of journals libraries in advanced countries. But the Internet and the World Wide Web initially exacerbated the gap between the rich and the poor countries, as many poor countries were slow to acquire these technologies and the infrastructure (especially bandwidth). Soon it became clear that thanks to these technologies we now have the unprecedented opportunity of having a level playing field in the matter of accessing scientific and scholarly information. Transforming this opportunity into reality is entirely in the hands of the researchers themselves. Imagine a world where every scientist places his/ her research papers, which (s)he wants to give away so others can read and make use of, in a public archive. Anyone anywhere in the world, of course having an Internet connection, can access, download, and read those papers. This is a win-win situation for all: the reader gets to read what he wants to read at very little cost; the author gains greater visibility for his work and the work reported is likely to have greater impact than if it were to be made available only through a toll-access journal. Although the logic is so simple, in reality such archives were not coming up for a very long time. In spite of the fact that computer scientists and physicists had shown about 15 years ago the great advantages of such archives. Recent studies by Alma Swan and others have shown that a very large proportion of scientists are not aware of open access and therefore what we need is focused advocacy. Even among those who know of OA, many are not depositing their papers in archives but say they would if they are asked by their bosses or their funding agencies. Clearly the ball is in the court of scientists and policy makers. OA is especially advantageous to the developing countries as the current access to literatures is poorest in these countries.展开更多
基金Project(51105017) supported by the National Natural Science Foundation of ChinaProject(2011BAG09B00) supported by the National Science and Technology Support Program of ChinaProject(2010DFB80020) supported by the Technology Major Project of the Ministry of Science and Technology of China
文摘For the purpose of engineering development for a new 8-step speed automatic transmission,a simplified dynamic model for this gearbox was established and key parameters which affected the shift quality were analyzed.Aiming at four different shift types,the ideal characteristics of shift clutch and engine control were set up.By using torque estimation method,PI slip control algorithm and engine coordinated control principle,the control model and transmission controller were well developed for three shift phases which included rapid-fill phase,torque phase and inertia phase.The testing environment on the rig and prototype vehicle level was built and the testing results obtained in ultimate condition could verify the accuracy and feasibility of this shift control strategy.The peak jerk during shift process was controlled within ±2 g/s where the smooth gearshift was obtained.The development proposal and algorithm have a high value for engineering application.
文摘Till about 15 years ago, almost all information exchange among scientists and scholars was mediated by print and even then researchers in the developing countries were at a great disadvantage as their libraries did not have the resources to subscribe in comparison with even a small fraction of journals libraries in advanced countries. But the Internet and the World Wide Web initially exacerbated the gap between the rich and the poor countries, as many poor countries were slow to acquire these technologies and the infrastructure (especially bandwidth). Soon it became clear that thanks to these technologies we now have the unprecedented opportunity of having a level playing field in the matter of accessing scientific and scholarly information. Transforming this opportunity into reality is entirely in the hands of the researchers themselves. Imagine a world where every scientist places his/ her research papers, which (s)he wants to give away so others can read and make use of, in a public archive. Anyone anywhere in the world, of course having an Internet connection, can access, download, and read those papers. This is a win-win situation for all: the reader gets to read what he wants to read at very little cost; the author gains greater visibility for his work and the work reported is likely to have greater impact than if it were to be made available only through a toll-access journal. Although the logic is so simple, in reality such archives were not coming up for a very long time. In spite of the fact that computer scientists and physicists had shown about 15 years ago the great advantages of such archives. Recent studies by Alma Swan and others have shown that a very large proportion of scientists are not aware of open access and therefore what we need is focused advocacy. Even among those who know of OA, many are not depositing their papers in archives but say they would if they are asked by their bosses or their funding agencies. Clearly the ball is in the court of scientists and policy makers. OA is especially advantageous to the developing countries as the current access to literatures is poorest in these countries.
