Towing tractor drivelines are lightly damped non-linear systems. Interactions between components can cause dynamic behavors such as gear gap impact in gear transmissions, shuffle and clonk phenomena in driveline. The ...Towing tractor drivelines are lightly damped non-linear systems. Interactions between components can cause dynamic behavors such as gear gap impact in gear transmissions, shuffle and clonk phenomena in driveline. The torsional vibration of driveline has an important effect on grand engineering vehicle vibration and noise. Through analyzing torsional vibration equations of driveline, torsional vibration model of driveline is developed by using Matlab/Simulink software, Shuffle and clonk phenomena are observed in torsional vibration. The modeling method of analysizing driveline torsional vibration can be used to research and improve similar engineering vehicle driveline behavors.展开更多
Researchers face di culties in studying the e ects of driveline e ciency on car fuel economy via bench and road tests because of long working periods, high costs, and heavy workloads. To simplify the study process and...Researchers face di culties in studying the e ects of driveline e ciency on car fuel economy via bench and road tests because of long working periods, high costs, and heavy workloads. To simplify the study process and shorten test cycles, a car fuel economy simulation forecast method for combining computer simulation forecasting with bench tests is proposed. Taking a continuously variable transmission(CVT) as the research object, a transmission e ?ciency model based on a bench test is constructed. An optimal economic variogram based on the original CVT vari?ogram, the boundary conditions of vehicle performance, the road conditions and the driving behavior of the driver is generated in the Gear Shift Program(GSP)?Generation module in AVL Cruise. And on this basis a driveline simulation model that can calculate the fuel consumption based on the driveline data of a test car is built. The model is used to forecast fuel consumption and calculate real?time CVT e ciency under di erent conditions. Contrastive analyses on simulation results and real car drum test results are made. The largest error between simulation results and drum test results in driving cycles is 4.099%, which is 5.449% under constant velocity condition in driver control mode and 4.2% under constant velocity condition in automatic cruise mode. The results confirm the feasibility of the method and the good performance of the driveline simulation model in accurately forecasting fuel consumption. The method can e ciently investigate the e ects of driveline e ciency on car fuel economy. Moreover, this research provides instruc?tion for accurately forecasting fuel economy as well as references for studies on the e ects of drivelines on car fuel economy.展开更多
The increased use of mechanical circulatory support has led to a rise in infectious complications in the recent years predisposing this population of patients to higher morbidity and mortality. In this study, we repor...The increased use of mechanical circulatory support has led to a rise in infectious complications in the recent years predisposing this population of patients to higher morbidity and mortality. In this study, we report a significantly lower rate of driveline infections of 0.12 episodes/patient-year as compared to the rates reported in the existing literature in patients with the HMII (Heartmate II). The study is limited by the fact that it is based on a small population of patients and was conducted retrospectively making recall bias hard to rule out. It is strictly restricted to one type of continuous flow pump (HMII) solely to decrease variations in the data reviewed. The exact cause of the low infection rate noted in this study is difficult to define. However, detailed teaching to the caregivers and the patient as well as close follow-ups in the perioperative period may substantially contribute to the outcome noted. Continued research limited to similar continuous flow ventricular assist devices in larger study populations would shed light on defining causes of infections in this population and developing robust algorithms to prevent such complications.展开更多
文摘Towing tractor drivelines are lightly damped non-linear systems. Interactions between components can cause dynamic behavors such as gear gap impact in gear transmissions, shuffle and clonk phenomena in driveline. The torsional vibration of driveline has an important effect on grand engineering vehicle vibration and noise. Through analyzing torsional vibration equations of driveline, torsional vibration model of driveline is developed by using Matlab/Simulink software, Shuffle and clonk phenomena are observed in torsional vibration. The modeling method of analysizing driveline torsional vibration can be used to research and improve similar engineering vehicle driveline behavors.
基金Supported by National Natural Science Foundation of China(Grant No.51575220)International S&T Cooperation Program of China(Grant No.2014DFA71790)
文摘Researchers face di culties in studying the e ects of driveline e ciency on car fuel economy via bench and road tests because of long working periods, high costs, and heavy workloads. To simplify the study process and shorten test cycles, a car fuel economy simulation forecast method for combining computer simulation forecasting with bench tests is proposed. Taking a continuously variable transmission(CVT) as the research object, a transmission e ?ciency model based on a bench test is constructed. An optimal economic variogram based on the original CVT vari?ogram, the boundary conditions of vehicle performance, the road conditions and the driving behavior of the driver is generated in the Gear Shift Program(GSP)?Generation module in AVL Cruise. And on this basis a driveline simulation model that can calculate the fuel consumption based on the driveline data of a test car is built. The model is used to forecast fuel consumption and calculate real?time CVT e ciency under di erent conditions. Contrastive analyses on simulation results and real car drum test results are made. The largest error between simulation results and drum test results in driving cycles is 4.099%, which is 5.449% under constant velocity condition in driver control mode and 4.2% under constant velocity condition in automatic cruise mode. The results confirm the feasibility of the method and the good performance of the driveline simulation model in accurately forecasting fuel consumption. The method can e ciently investigate the e ects of driveline e ciency on car fuel economy. Moreover, this research provides instruc?tion for accurately forecasting fuel economy as well as references for studies on the e ects of drivelines on car fuel economy.
文摘The increased use of mechanical circulatory support has led to a rise in infectious complications in the recent years predisposing this population of patients to higher morbidity and mortality. In this study, we report a significantly lower rate of driveline infections of 0.12 episodes/patient-year as compared to the rates reported in the existing literature in patients with the HMII (Heartmate II). The study is limited by the fact that it is based on a small population of patients and was conducted retrospectively making recall bias hard to rule out. It is strictly restricted to one type of continuous flow pump (HMII) solely to decrease variations in the data reviewed. The exact cause of the low infection rate noted in this study is difficult to define. However, detailed teaching to the caregivers and the patient as well as close follow-ups in the perioperative period may substantially contribute to the outcome noted. Continued research limited to similar continuous flow ventricular assist devices in larger study populations would shed light on defining causes of infections in this population and developing robust algorithms to prevent such complications.
