Research Papers - Department of Mechanical Engineering

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    PublicationOpen Access
    Comparing Fuel Consumption and Emission Levels of Hybrid Powertrain Configurations and a Conventional Powertrain in Varied Drive Cycles and Degree of Hybridization
    (Белорусский национальный технический университет, 2020) Maddumage, W. U; Abeyasighe, K. Y; Perera, M. S. M; Attalage, R; Kelly, P
    The use of hybrid electric transmissions in the automotive industry is a solution to the problem of emissions and fuel economy compared to conventional combustion engine vehicles. To achieve the desired results, when designing a hybrid electric vehicle, it is necessary to consider various options, while taking into account fuel consumption and exhaust emissions. The article presents an analysis of the design of an automobile transmission, various options and situations are considered, for example, the target driving cycle and the degree of hybridization. Four transmission configuration models (combustion engine, serial, parallel and complex hybrid transmission configurations) for a small vehicle (motorized three-wheeler) have been developed using Model Advisor software. The listed transmission configurations have been modeled with different driving cycles and varying degrees of hybridization. First, the impact of the vehicle's power management strategy and the performance of various transmission configurations is investigated based on the analysis of exhaust emissions and fuel consumption. Second, driving cycles are scaled according to kinetic intensity and the relationship between fuel consumption and driving cycles is estimated. Thirdly, three fuel consumption models have been developed so that the fuel consumption for an actual driving cycle can be predicted for each transmission configuration. Studies have shown that compared to a conventional transmission, fuel consumption is lower in hybrid vehicles. The tests gave an unexpected result: higher levels of CO emissions from hybrid vehicles. In addition, the fuel consumption of all four transmissions indicates a strong correlation with the kinetic intensity values ​​of the selected driving cycles. It was found that for different driving cycles, the average fuel preference for each cycle was: 23% for sequential, 21% for parallel and 33% for complex hybrids in comparison with the transmission of an internal combustion engine. Experiments have shown that the performance of hybrid configurations varies depending on the driving cycle and degree of hybridization. The article identifies promising areas of research. It was found that for different driving cycles, the average fuel preference for each cycle was: 23% for sequential, 21% for parallel and 33% for complex hybrids in comparison with the transmission of an internal combustion engine. Experiments have shown that the performance of hybrid configurations varies depending on the driving cycle and degree of hybridization. The article identifies promising areas of research. It was found that for different driving cycles, the average fuel preference for each cycle was: 23% for sequential, 21% for parallel and 33% for complex hybrids in comparison with the transmission of an internal combustion engine. Experiments have shown that the performance of hybrid configurations varies depending on the driving cycle and degree of hybridization. The article identifies promising areas of research.
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    PublicationOpen Access
    Power Management Strategy of a Parallel Hybrid Three-Wheeler for Fuel and Emission Reduction
    (Multidisciplinary Digital Publishing Institute, 2021-01) Maddumage, W; Perera, M; Attalage, R; Kelly, P
    Millions of three-wheelers in large cities of Asia and Africa contribute to the already increasing urban air pollutants. An emerging method to reduce adverse effects of the growing threewheeler fleet is hybrid-electric technology. The overall efficiency of a hybrid electric vehicle heavily depends on the power management strategy used in controlling the main powertrain components of the vehicle. Recent studies highlight the need for a comprehensive report on developing an easyto-implement and efficient control strategy for hybrid electric three-wheelers. Thus, in the present study, a design methodology for a rule-based supervisory controller of a pre-transmission parallel hybrid three-wheeler based on an optimal control strategy (i.e., dynamic programming) is proposed. The optimal control problem for minimizing fuel, emissions (i.e., HC, CO and NOx) and gear shift frequency are solved using dynamic programming (DP). Numerical issues of DP are analyzed and trade-offs between optimizing objectives are presented. Since DP strategy cannot be implemented as a real-time controller, useful strategies are extracted to develop the proposed rule-based strategy. The developed rule-based strategy show performance within 10% of the DP results on WLTC and UDC-NEDC drive cycles and has the clear advantage of being near-optimal, easy-to-implement and computationally less demanding.