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Research On Several Key Techniques Of12V Start&Stop System For Vehicle

Posted on:2015-02-12Degree:MasterType:Thesis
Country:ChinaCandidate:Y G LuoFull Text:PDF
GTID:2252330428956435Subject:Mechanical engineering
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Car manufacturers have more and more challenges now, as the government is requesting higher requirement for car fuel consumption and emission. Almost all car manufactures take effort on developing high efficiency and environment friendly powertrain solution, includes Start&Stop system, Hybrid system, Plug in hybrid system, Electrical Vehicle, Extended Range Electrical Vehicle, fuel battery system and so on. Obviously12V Start&Stop system is the most quick solution based on existing vehicle, it is also as the low cost solution to improve the fuel economy.12V Start&Stop system stops traditional engine automatically at certain condition (such as temporarily stop waiting for traffic lamp), which saves fuel and emission during engine idle. This improvement will be great at the city road condition due to frequently vehicle stop. But12V Start&Stop system is still under development process, lots of issue needs to be fixed. This paper will focused on some key issues.The special running mode of12V Start&Stop system takes higher requirement for engineering development. Different driving style and vehicle usage makes different impact on Start&Stop system, vehicle usage data has to be measured based on actual condition. In order to support new vehicle development, vehicle big data measurement system is set up. The system is based on updated mobile communication technology and vehicle CAN bus signal. More than20provinces in China and more than30customer’s vehicle data is recorded, the big data contains important information, such as vehicle running status, customer driving usage. Depend on purpose for data, the system could export required statistical math, which will be as basic for new vehicle development.Based on the big data information, battery service life is calculated at beginning of vehicle program. Distribution of auto stop duration is available from the big data system. With distribution of electrical load at auto stop duration, distribution of battery DOD could be calculated. DOD distribution caused by deep discharge cycle, key cranking and vehicle shut down process are also calculated. Then we got battery service life distribution by integration of these DOD distributions(via calculation life consumption per10K charge cycle) and charging cycle time yearly. As national requirement is one year for vehicle battery, this calculation method could support new vehicle development. Evaluation strategy of battery key status parameter is performed. Traditionalbattery State of Charge (SOC) evaluation strategy is presented simply, it is clarified that State of Function (SOF) is more important for Start&Stop vehicle, which directly indicate battery cranking ability and providing prediction of the lowest voltage value during auto start. Based on battery Thevenin model, it is presented the method to calculate the lowest voltage during auto start, which could use generator ripple voltage and could cranking process. This SOF evaluation method is validated by vehicle test.Virtual analysis platform for Start&Stop vehicle electrical power system is set up. Vehicle simulation model ADVISOR is introduced. Generator model, battery model, load model and Start&Stop model are created in SIMULINK, and they are integrated into ADVISOR. Then user operation interface is built based on engineering analysis requirement. We got vehicle charge balance performance result at critical condition with input all required data to the system. The result shows electrical power system of the vehicle could satisfy charge balance requirement at idle, city and high way road condition...
Keywords/Search Tags:start&stop system, big data, battery, life, generator, simulation
PDF Full Text Request
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