Seite - 267 - in Emerging Technologies for Electric and Hybrid Vehicles

Energies 2017,10, 437 Bdoesnotmeet therequirements. Inaddition, it is foundthat theengineneeds tobe locatedat the centernodeof leverA, i.e., at carrierC, since theorderof thePGnodeshouldbeS,C,RorR,C,S (fromcondition(b)). (a) (b) 2XWSXW 0* E L D 0* ,QSXW (QJLQH 2XWSXW 0* L D ,QSXW (QJLQH 0* E Figure1.Ageneralizedsingle levermodel for the inputsplitplug-inhybridelectricvehicle (PHEV). (a)LeverA; (b)LeverB. D L F B A Figure2.Speedratioat themechanicalpoint [20]. Now,wedeterminethepositionofMG2(output).MG2canbelocatedatthesungear,S(Figure3a), or theringgear,R(Figure3b). Fromthespeedleveranalogy, it is foundthatMG2ispositionedat the ringgearwhen a/i isgreater than2;meanwhile it ispositionedat thesungear for1< a/i<2. Fromthe leveranalogyof thespeedandtorque,wecanobtain thepowerofeachnodeusing a/i. Defining thepower ratioPRas the ratioof theMG1power (electricalpower) to theengine (input) power, thepowerratio is representedas PR= PMG1 Pe = ωout ωe ( 1 (a/i)−1 ) +1 (3) InFigure4, thepowerratio isshownfora/ibetween1and3.5whentheenginespeedis1500rpm, theengine torque is100Nm,andtheoutputspeed is2000rpm. It is seenfromFigure4 that thepower ratiodecreasesasa/i increases. SincethePSTefficiencyincreasesas thepowerratiodecreases, inother words, thepower throughMG1(electricalpath)decreases,wefindthatMG2needs tobepositionedat theringgear. 267