呂康輝 廖萍 王晨 程輝軍 周文太
摘 ?要: 為研究功率分流式混合動(dòng)力系統(tǒng)整車高速工況經(jīng)濟(jì)性優(yōu)化問題,提出在高速工況下采用制動(dòng)器B2鎖止、功率損耗最小的控制策略方案。綜合考慮發(fā)動(dòng)機(jī)、電機(jī)、電池的功率損耗,建立混合動(dòng)力系統(tǒng)模型,并對(duì)該方案進(jìn)行仿真驗(yàn)證及整車試驗(yàn)。結(jié)果顯示,優(yōu)化后的整車高速工況經(jīng)濟(jì)性有明顯提升。制動(dòng)器B2鎖止、功率損耗最小的控制策略有助于提升整車高速工況經(jīng)濟(jì)性。
關(guān)鍵詞: 功率分流; 混合動(dòng)力; 高速工況; 經(jīng)濟(jì)性; 控制策略; 仿真驗(yàn)證
中圖分類號(hào): TN98?34 ? ? ? ? ? ? ? ? ? ? ? ? ?文獻(xiàn)標(biāo)識(shí)碼: A ? ? ? ? ? ? ? ? ? ? ? ? ? 文章編號(hào): 1004?373X(2019)09?0072?04
Research on fuel consumption of vehicle′s power split hybrid
powertrain at high?speed operation
L? Kanghui1, LIAO Ping1, WANG Chen2, CHENG Huijun2, ZHOU Wentai2
(1. School of Mechanical Engineering, Nantong University, Nantong 226019, China;
2. Corun Hybrid Power Technology Co., Ltd., Shanghai 201500, China)
Abstract: In order to research the fuel consumption optimization of the vehicle′s power split hybrid powertrain at high?speed operation, a control strategy to lock the brake B2 and make the vehicle′s system with minimum power loss at high?speed operation is proposed. The power loss of the engine, motor and battery was comprehensively considered, the hybrid power system model was established, and the simulation verification and vehicle test were performed for the scheme. The result shows that the fuel consumption of the optimized vehicle at high?speed operation has obviously improved. The control strategy to lock the brake B2 and make the system with minimum power loss is contribute to reduce the fuel consumption of the vehicle at high?speed operation.
Keywords: power split; hybrid power; high?speed operation; fuel consumption; control strategy; simulation verification
0 ?引 ?言
在傳統(tǒng)的內(nèi)燃機(jī)汽車向新能源汽車發(fā)展的過程中,混合動(dòng)力汽車作為一種過渡車型,因具有污染小、油耗低、動(dòng)力性強(qiáng)等優(yōu)勢,獲得了越來越廣泛的應(yīng)用[1?2]。
以豐田Prius的機(jī)械功率分流系統(tǒng)為代表[3],通過雙電機(jī)轉(zhuǎn)速和扭矩調(diào)整發(fā)動(dòng)機(jī)工作于最佳運(yùn)行區(qū)域,達(dá)到節(jié)能減排的目的[4],可以實(shí)現(xiàn)40%以上的節(jié)油效果[5]。本文介紹一種功率分流式混合動(dòng)力系統(tǒng),由于其具有多種工作模式,控制策略有待進(jìn)一步挖掘完善,燃油經(jīng)濟(jì)性有待進(jìn)一步提高。
1 ?高速工況B2鎖止、功率損耗最小控制策略設(shè)計(jì)
由于系統(tǒng)在高速工況下總存在一個(gè)電機(jī)發(fā)電、另一個(gè)電機(jī)用電的電功率回環(huán)[6],影響了系統(tǒng)效率,利用制動(dòng)器B2將電機(jī)E1鎖止,等效杠桿[7]如圖1所示。此模式下僅電機(jī)E2工作,不存在電功率循環(huán),系統(tǒng)工作效率較高。
B2鎖止時(shí)車速滿足下列關(guān)系:
以功率損耗最小為控制目標(biāo),在滿足上述車速的條件下,由于電機(jī)E1轉(zhuǎn)速較高時(shí)鎖止制動(dòng)器B2會(huì)影響整車平順性。因此,對(duì)上述控制策略進(jìn)行修正:只有滿足電機(jī)E1轉(zhuǎn)速低于100 r/min時(shí),才允許制動(dòng)器B2鎖止。
本文研究的功率損耗忽略機(jī)械功率損耗[8],僅研究電機(jī)、電池、發(fā)動(dòng)機(jī)功率損耗。系統(tǒng)總的功率損耗可由下式得出:
2 ?混合動(dòng)力系統(tǒng)建模
2.1 ?發(fā)動(dòng)機(jī)模型
發(fā)動(dòng)機(jī)萬有特性曲線如圖2所示。
通過扭矩、轉(zhuǎn)速可查得比油耗,本文研究的發(fā)動(dòng)機(jī)經(jīng)濟(jì)比油耗取240 g/(kW[·]h),發(fā)動(dòng)機(jī)功率損耗可由下式得出:
2.2 ?電機(jī)E2模型
電機(jī)E2驅(qū)動(dòng)時(shí)的效率數(shù)值模型如圖3所示。其功率損耗可由下式得出:
同理,可建立電機(jī)E2發(fā)電效率數(shù)值模型以及電機(jī)E1驅(qū)動(dòng)、發(fā)電效率數(shù)值模型。
2.3 ?動(dòng)力電池模型
動(dòng)力電池簡化為一階模型[9],電池內(nèi)阻模型等效電路如圖4所示。
通過電池SOC可得到電池內(nèi)阻,通過電機(jī)功率及電池電壓可求得電池電流,動(dòng)力電池功率損耗可由下式得出:
2.4 ?整車動(dòng)力學(xué)模型
由等效杠桿工作原理可得出如下關(guān)系:
式中:[vspd]為汽車車速;[r]為車輪半徑;[i]為主減速比;[F]為整車行駛阻力;[G]為整車重力;[f]為滾動(dòng)阻力系數(shù);[CD]為空氣阻力系數(shù);[A]為整車迎風(fēng)面積。
3 ?仿真驗(yàn)證
3.1 ?發(fā)動(dòng)機(jī)工作點(diǎn)的確定
在各車速下,通過所有允許的發(fā)動(dòng)機(jī)轉(zhuǎn)速、扭矩組合,計(jì)算得到對(duì)應(yīng)的系統(tǒng)損耗功率。發(fā)動(dòng)機(jī)轉(zhuǎn)速與系統(tǒng)損耗功率關(guān)系曲線如圖6所示。
由圖6可知,在各個(gè)車速下都能找到一個(gè)系統(tǒng)損耗功率最小值,并且此時(shí)B2制動(dòng)器鎖止,發(fā)動(dòng)機(jī)轉(zhuǎn)速與車速呈線性關(guān)系,發(fā)動(dòng)機(jī)轉(zhuǎn)速和電機(jī)E2轉(zhuǎn)速隨著車速的增加而等比例增加。
圖7列出了系統(tǒng)功率損耗最小時(shí)對(duì)應(yīng)的車速與發(fā)動(dòng)機(jī)轉(zhuǎn)速和扭矩關(guān)系。
3.2 ?仿真驗(yàn)證
通過上述建立的模型以及由功率損耗最小確立的發(fā)動(dòng)機(jī)轉(zhuǎn)速、扭矩組合,以及發(fā)動(dòng)機(jī)工作最經(jīng)濟(jì)確定的發(fā)動(dòng)機(jī)轉(zhuǎn)速、扭矩組合,利用Matlab/Simulink進(jìn)行整車經(jīng)濟(jì)性仿真,整車參數(shù)如表1所示。
4 ?整車試驗(yàn)
通過前文所述的系統(tǒng)功率損耗最小以及發(fā)動(dòng)機(jī)工作最經(jīng)濟(jì)發(fā)動(dòng)機(jī)轉(zhuǎn)速、扭矩組合,分別進(jìn)行巡航80 km/h,90 km/h,100 km/h,110 km/h,120 km/h高速工況下整車油耗試驗(yàn)如圖8所示。
油耗試驗(yàn)結(jié)果表明,功率損耗最小控制策略更有利于提升整車高速工況經(jīng)濟(jì)性。隨著車速的增加,二者油耗的差距越來越小,原因是隨著車速的增加整車驅(qū)動(dòng)力減少,電機(jī)助力減少,SOC變化量減少,油耗幾乎全部來自發(fā)動(dòng)機(jī),120 km/h車速下,SOC變化量幾乎為0,二者油耗也趨于一致。各高速工況下電池SOC變化情況如圖10所示。
5 ?結(jié) ?語
本文基于功率分流式混合動(dòng)力系統(tǒng),提出在高速工況下,采用制動(dòng)器B2鎖止、功率損耗最小控制策略。建立混合動(dòng)力系統(tǒng)模型并進(jìn)行仿真驗(yàn)證及整車試驗(yàn)。結(jié)果表明,該策略有助于提升整車高速工況經(jīng)濟(jì)性,對(duì)類似雙電機(jī)混合動(dòng)力系統(tǒng)高速工況經(jīng)濟(jì)性優(yōu)化有一定參考價(jià)值。
參考文獻(xiàn)
[1] HAMUT H, S DINCER I, NATERER G F. Analysis and optimization of hybrid electric vehicle thermal management systems [J]. Journal of power sources, 2014, 247: 643?654.
[2] KAUR J, GAUR P, SAXENA P, et al. Speed control of hybrid electric vehicle using artificial intelligence techniques [J]. International journal of computing and network technology, 2014, 2(1): 33?39.
[3] MUTA K, YAMAZAKI M, TOKIEDA J. Development of new?generation hybrid system THS Ⅱ?drastic improvement of power performance and fuel economy [C]// 2004 SAE World Congress. Detroit: SAE, 2004: 1?13.
[4] NG H, ANDERSON J, DUOBA M, et al. Engine start characteristics of two hybrid electric vehicles (HEVs): Honda insight and Toyota Prius [C]// 2001 Future Transportation Technology Conference & Exposition. [S.l.]: SAE, 2001: 110?113.
[5] MILLER J M. Hybrid electric vehicle propulsion system architectures of the e?CVT type [J]. IEEE transactions on power electronics, 2006, 21(3): 756?767.
[6] 汪東坪.深度混合動(dòng)力汽車整車系統(tǒng)控制技術(shù)研究[D].南京:南京航空航天大學(xué),2013.
WANG Dongping. Research on control technology of vehicle system for deep hybrid vehicles [D]. Nanjing: Nanjing University of Aeronautics and Astronautics, 2013.
[7] 鄭雷,黃宗益,劉釗.行星機(jī)構(gòu)杠桿模擬法[J].筑路機(jī)械與施工機(jī)械化,2013,30(10):102?106.
ZHENG Lei, HUANG Zongyi, LIU Zhao. Leverage simulation of planetary mechanism [J]. Road construction machinery & construction mechanization, 2013, 30(10): 102?106.
[8] 齊蘊(yùn)龍,項(xiàng)昌樂,韓立金,等.基于傳動(dòng)效率的雙模式混合動(dòng)力車輛控制策略研究[J].北京汽車,2016(1):1?5.
QI Yunlong, XIANG Changle, HAN Lijin, et al. Research on control strategy of dual?mode hybrid vehicle based on transmission efficiency [J]. Beijing auto, 2016(1): 1?5.
[9] 郭明林,朱建新,王晨,等.新型功率分流混合動(dòng)力汽車能量管理策略仿真[J].計(jì)算機(jī)仿真,2015,32(7):137?143.
GUO Minglin, ZHU Jianxin, WANG Chen, et al. Simulation of energy management strategy for a novel power split hybrid vehicle [J]. Computer simulation, 2015, 32(7): 137?143.
[10] 余志生.汽車?yán)碚揫M].北京:機(jī)械工業(yè)出版社,2009.
YU Zhisheng. Automotive theory [M]. Beijing: China Machine Press, 2009.