The Effect Of Communication System On Starter Mechanical Performance

Starter is a very important component of a car,it’s the most useful tool to start car in these days.Because of its simple structure and easy control,good performance and low cost,the DC brush motor is used as an important part in starter.The power of battery is converted to mechanical rotation by DC brush motor,then after gear reduction this rotation is used to drive the ring gear of car engine to its self rotation.Starter has a physical commutation system,and this communication is very complicated because it contains many phenomena,such as contains electricity,light,heat,noise,chemistry,etc.Especially starter works with low voltage but large current,and with bad working condition,starts frequently.The phenomena have big effects on starter performance,such as mechanical performance,robust,life time,if bad communication.As there are many effects and they are interacted,starter communication is hard to be showed clearly,more work should be done for this important communication issues.This paper focus on the effect from communication on starter mechanical performance.This paper focus the research of the performance loss of the starter,especially focus on the research of effects on the performance loss.After compare the performance data after endurance test and before endurance test,we find that the communication structure would be the most important effect on performance.Secondly,we exchange the new carbon brush,commutator on old test starter,we find that the communication contact resistance would be the most important effect.The shift angle of communication would be the second important effect.The communication resistance major come from copper oxidation in carbon brush and communication bar.This communication resistance change also enlarge the effect of communication shift angle,because the communication resistance change reduce the shift angle much more.As less shift angle meet less working current.But the current of starter varies at different situation.So the shift angle change worsen the matched situation and lead starter communication get worse.Then these two changes lead to communication resistance increase and shift angle reduce.Analysis starter performance requirement based on China Starter specification,and discuss the communication theory and communication spark.Later introduce the communication model and the major effects on the communication performance basedon this model,discuss the important parts design of brush,commutator and magnet in communication systemTo find a suitable brush shift angle,the finite element analysis method is introduced to find out how the working current reaction on major airgap magnetic flux density.And how the zero of magnetic flux density will move at different working current.This movement of zero of magnetic flux density leads to shift angle change.And also calculate the mechanical performance change at different shift angle by finite element analysis.The test result approve the analysis correct.The result of this paper is useful for people to find the relationship between starter performance and starter problem,it’s also useful for problem solving of other similar motor.