分析了以电容器为蓄能装置的液压挖掘机并联混合动力系统的结构,在此基础上,针对液压挖掘机的工况,提出了以发动机工作点和电容器荷电状态(state of charge,SOC)值为优化变量的控制策略,并建立了试验系统对该控制策略进行试验研究。研...分析了以电容器为蓄能装置的液压挖掘机并联混合动力系统的结构,在此基础上,针对液压挖掘机的工况,提出了以发动机工作点和电容器荷电状态(state of charge,SOC)值为优化变量的控制策略,并建立了试验系统对该控制策略进行试验研究。研究结果表明,采用该控制策略后,改善了发动机工作点的分布区域,抑制了电容器SOC的变化幅度,且基本不影响系统的响应性能。展开更多
针对大功率轮式拖拉机存在的档位过多、操作复杂和牵引效率低等问题,基于拖拉机工作特点、并联混合动力传动系统原理和拖拉机犁耕工况下的负载特性,对132 k W并联混合动力拖拉机的动力系统、耦合系统和传动系统等相关参数进行了合理匹...针对大功率轮式拖拉机存在的档位过多、操作复杂和牵引效率低等问题,基于拖拉机工作特点、并联混合动力传动系统原理和拖拉机犁耕工况下的负载特性,对132 k W并联混合动力拖拉机的动力系统、耦合系统和传动系统等相关参数进行了合理匹配设计。结合给定的输出特性目标及控制方案,对并联混合动力拖拉机的理论牵引特性进行分析,并与东方红-1804大功率轮式拖拉机对比。对比结果表明:并联式混合动力拖拉机的牵引效率特性、滑转率特性、动力输出功率特性、牵引功率特性和行驶速度特性等理论牵引特性的各项指标均有一定的改善,牵引性能更优越。其动力性和经济性得到提高,并减少了档位数量,有利于传动系统的结构简化和操控。展开更多
For a series plug-in hybrid electric vehicle,higher working efficiency can be achieved by the drive system with two small motors in parallel than that with one big motor alone.However,the overly complex structure will...For a series plug-in hybrid electric vehicle,higher working efficiency can be achieved by the drive system with two small motors in parallel than that with one big motor alone.However,the overly complex structure will inevitably lead to a substantial increase in the development cost.To improve the system price-performance ratio,a new kind of series-parallel hybrid system evolved from the series plug-in hybrid system is designed.According to the technical parameters of the selected components,the system model is established,and the vehicle dynamic property and pure electric drive economy are evaluated.Based on the dynamic programming,the energy management strategy for the drive system under the city driving cycle is developed,and the superiority validation of the system is completed.For the studied vehicle driven by the designed series-parallel plug-in hybrid system,compared with the one driven by the described series plug-in hybrid system,the dynamic property is significantly improved because of the multi-power coupling,and the fuel consumption is reduced by 11.4%with 10 city driving cycles.In a word,with the flexible configuration of the designed hybrid system and the optimized control strategy of the energy management,the vehicle performance can be obviously improved.展开更多
In this paper, we present a predictive prefetching mechanism that is based on probability graph approach to perform prefetching between different levels in a parallel hybrid storage system. The fundamental concept of ...In this paper, we present a predictive prefetching mechanism that is based on probability graph approach to perform prefetching between different levels in a parallel hybrid storage system. The fundamental concept of our approach is to invoke parallel hybrid storage system’s parallelism and prefetch data among multiple storage levels (e.g. solid state disks, and hard disk drives) in parallel with the application’s on-demand I/O reading requests. In this study, we show that a predictive prefetching across multiple storage levels is an efficient technique for placing near future needed data blocks in the uppermost levels near the application. Our PPHSS approach extends previous ideas of predictive prefetching in two ways: (1) our approach reduces applications’ execution elapsed time by keeping data blocks that are predicted to be accessed in the near future cached in the uppermost level;(2) we propose a parallel data fetching scheme in which multiple fetching mechanisms (i.e. predictive prefetching and application’s on-demand data requests) can work in parallel;where the first one fetches data blocks among the different levels of the hybrid storage systems (i.e. low-level (slow) to high-level (fast) storage devices) and the other one fetches the data from the storage system to the application. Our PPHSS strategy integrated with the predictive prefetching mechanism significantly reduces overall I/O access time in a hybrid storage system. Finally, we developed a simulator to evaluate the performance of the proposed predictive prefetching scheme in the context of hybrid storage systems. Our results show that our PPHSS can improve system performance by 4% across real-world I/O traces without the need of using large size caches.展开更多
To solve the low power density issue of hybrid electric vehicular batteries, a combination of batteries and ultracapacitors (UCs) could be a solution. The high power density feature of UCs can improve the performance ...To solve the low power density issue of hybrid electric vehicular batteries, a combination of batteries and ultracapacitors (UCs) could be a solution. The high power density feature of UCs can improve the performance of battery/UC hybrid energy storage systems (HESSs). This paper presents a parallel hybrid electric vehicle (HEV) equipped with an internal combus- tion engine and an HESS. An advanced energy management strategy (EMS), mainly based on fuzzy logic, is proposed to improve the fuel economy of the HEV and the endurance of the HESS. The EMS is capable of determining the ideal distribution of output power among the internal combustion engine, battery, and UC according to the propelling power or regenerative braking power of the vehicle. To validate the effectiveness of the EMS, numerical simulation and experimental validations are carried out. The results indicate that EMS can effectively control the power sources to work within their respective efficient areas. The battery load can be mitigated and prolonged battery life can be expected. The electrical energy consumption in the HESS is reduced by 3.91% compared with that in the battery only system. Fuel consumption of the HEV is reduced by 24.3% compared with that of the same class conventional vehicles under Economic Commission of Europe driving cycle.展开更多
文摘分析了以电容器为蓄能装置的液压挖掘机并联混合动力系统的结构,在此基础上,针对液压挖掘机的工况,提出了以发动机工作点和电容器荷电状态(state of charge,SOC)值为优化变量的控制策略,并建立了试验系统对该控制策略进行试验研究。研究结果表明,采用该控制策略后,改善了发动机工作点的分布区域,抑制了电容器SOC的变化幅度,且基本不影响系统的响应性能。
文摘针对大功率轮式拖拉机存在的档位过多、操作复杂和牵引效率低等问题,基于拖拉机工作特点、并联混合动力传动系统原理和拖拉机犁耕工况下的负载特性,对132 k W并联混合动力拖拉机的动力系统、耦合系统和传动系统等相关参数进行了合理匹配设计。结合给定的输出特性目标及控制方案,对并联混合动力拖拉机的理论牵引特性进行分析,并与东方红-1804大功率轮式拖拉机对比。对比结果表明:并联式混合动力拖拉机的牵引效率特性、滑转率特性、动力输出功率特性、牵引功率特性和行驶速度特性等理论牵引特性的各项指标均有一定的改善,牵引性能更优越。其动力性和经济性得到提高,并减少了档位数量,有利于传动系统的结构简化和操控。
基金supported by the National Natural Science Foundation of China(Grant No.51405259)China Postdoctoral Science Foundation funded project(Grant Nos.2014T70072&2013M530608)Colleges and Universities in Hebei Province Science and Technology Research Project(Grant No.QN2015056)
文摘For a series plug-in hybrid electric vehicle,higher working efficiency can be achieved by the drive system with two small motors in parallel than that with one big motor alone.However,the overly complex structure will inevitably lead to a substantial increase in the development cost.To improve the system price-performance ratio,a new kind of series-parallel hybrid system evolved from the series plug-in hybrid system is designed.According to the technical parameters of the selected components,the system model is established,and the vehicle dynamic property and pure electric drive economy are evaluated.Based on the dynamic programming,the energy management strategy for the drive system under the city driving cycle is developed,and the superiority validation of the system is completed.For the studied vehicle driven by the designed series-parallel plug-in hybrid system,compared with the one driven by the described series plug-in hybrid system,the dynamic property is significantly improved because of the multi-power coupling,and the fuel consumption is reduced by 11.4%with 10 city driving cycles.In a word,with the flexible configuration of the designed hybrid system and the optimized control strategy of the energy management,the vehicle performance can be obviously improved.
文摘In this paper, we present a predictive prefetching mechanism that is based on probability graph approach to perform prefetching between different levels in a parallel hybrid storage system. The fundamental concept of our approach is to invoke parallel hybrid storage system’s parallelism and prefetch data among multiple storage levels (e.g. solid state disks, and hard disk drives) in parallel with the application’s on-demand I/O reading requests. In this study, we show that a predictive prefetching across multiple storage levels is an efficient technique for placing near future needed data blocks in the uppermost levels near the application. Our PPHSS approach extends previous ideas of predictive prefetching in two ways: (1) our approach reduces applications’ execution elapsed time by keeping data blocks that are predicted to be accessed in the near future cached in the uppermost level;(2) we propose a parallel data fetching scheme in which multiple fetching mechanisms (i.e. predictive prefetching and application’s on-demand data requests) can work in parallel;where the first one fetches data blocks among the different levels of the hybrid storage systems (i.e. low-level (slow) to high-level (fast) storage devices) and the other one fetches the data from the storage system to the application. Our PPHSS strategy integrated with the predictive prefetching mechanism significantly reduces overall I/O access time in a hybrid storage system. Finally, we developed a simulator to evaluate the performance of the proposed predictive prefetching scheme in the context of hybrid storage systems. Our results show that our PPHSS can improve system performance by 4% across real-world I/O traces without the need of using large size caches.
基金Project (No. RD-07-267) supported by the General Motors
文摘To solve the low power density issue of hybrid electric vehicular batteries, a combination of batteries and ultracapacitors (UCs) could be a solution. The high power density feature of UCs can improve the performance of battery/UC hybrid energy storage systems (HESSs). This paper presents a parallel hybrid electric vehicle (HEV) equipped with an internal combus- tion engine and an HESS. An advanced energy management strategy (EMS), mainly based on fuzzy logic, is proposed to improve the fuel economy of the HEV and the endurance of the HESS. The EMS is capable of determining the ideal distribution of output power among the internal combustion engine, battery, and UC according to the propelling power or regenerative braking power of the vehicle. To validate the effectiveness of the EMS, numerical simulation and experimental validations are carried out. The results indicate that EMS can effectively control the power sources to work within their respective efficient areas. The battery load can be mitigated and prolonged battery life can be expected. The electrical energy consumption in the HESS is reduced by 3.91% compared with that in the battery only system. Fuel consumption of the HEV is reduced by 24.3% compared with that of the same class conventional vehicles under Economic Commission of Europe driving cycle.
