Reliability of Combustion Engine Electric Equipment

8/12/2019 Reliability of Combustion Engine Electric Equipment

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University of PitestiFaculty of Mechanical Engineering and Technology

RELIABILITY OF COMBUSTION ENGINE

ELECTRIC EQUIPMENT

Supervisor: prof.

PhD. BOO!U "le#andru

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Student: B!$"$ornel

SUMM"%:

&. !'TODU$T!O'

(. T)E SU*E% OF E+E$T!$ "'D E+E$TO'!$ S%STEMS(.&. Functional "nalysis $oncerning the Starting Syste, elia-ility(.(. Functional "nalysis $oncerning the $harging Syste, elia-ility(.. Functional "nalysis $oncerning the !gnition Syste, elia-ility(./. Functional "nalysis $oncerning the !n0ection Syste, elia-ility

. E1PE!ME'T"+ STUD!ES

/. E+!"B!+!T% MODE+S OF E+E$TO'!$ E'2!'E E3U!PME'T $)OSE'E+EME'TS

4. $O'$+US!O'S

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)igh rotational speed of starter 9ith a series of e#citation 9hile itAs 9or;ing innoload state lead to -earings 9ear and rotor da,age. The introduction of additionalshunt 9inding ,a;es it possi-le to decrease rotational speed at 9or; in noloadstate considera-ly and conse7uently to ensure relia-le starter 9or; for a longerti,e.

!n starters 9ith planetary gears5 a planetary gear is used for reducing therotational speed of the rotor of the direct current electric ,otor. The coupling lever,eshes the pinion in the sa,e 9ay as in a conventional starter.

Three planet 9heels and a


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Functional Analysis Conc!nin" t# In&ction Syst$ Rlia%ility

EE$* in0ection syste, has -een used in FOD Fiesta since &HH4. !t is theelectronically controlled in0ection and ignition syste, reali=ed in digital electronics.Fuel is in0ected into the suction ,anifold in a discontinuous 9ay. !gnition is

controlled -y characteristics stored in the central control syste,. Signal a-out thede,and for fuel5 depending on the suc;ed air 7uantity5 is trans,itted to the centralcontrol syste, as an electric signal co,ing fro, the air


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Figure 3.3. Diagram of charging system reliability structure

Figure 3.4. Diagram of electronic ignition system reliability structure

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Figure 3.5. Diagram of injection system reliability structure

The state,ent of electric e7uip,ent failures5 in 9hich Model F5 S5 M cars have-een ta;en as e#a,ples5 is presented in Fig. .J.H.

Figure 3.6. The statement of starter failures

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Figure 3.7. The statement of alternator failures

Figure 3.8. The statement of control unit failures

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Figure 3.9. The statement of engine control unit failures

4. RELIA*ILITY MODELS OF ELECTRONIC EN+INE E,UI)MENTCHOSEN ELEMENTS

On the grounds of registered results and 9ith the use of the co,puter progra,KStatisticaL have -een prepared relia-ility ,odels of vehicle electric ele,ents >seeFig. /.&/./?.

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Figure 4.1. ontrol unit ignition em!irical reliability function

Figure 4.". ontrol unit ignition reliability mo#el $e%!ecte# &alue'

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Figure 4.3. (ngine control unit em!irical reliability function

Figure 4.4. (ngine control unit reliability mo#el $e%!ecte# &alue'

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-. CONCLUSIONS

&. The conditions of auto,otive electronic syste,s ,aintenance are very dicult-ecause se,iconductor ele,ents are sensitive to te,perature and hu,idity

changes5 ,echanical shoc;s and vi-ration5 9ater5 grease and che,icals i,pactC-esides they are very sensitive to electro,agnetic interference and e#cessivevoltage increase.

(. Electronic syste,s are su-0ect to te,perature changes in a very 9ide rangedepending on the place in the car in 9hich they are installed. Te,perature changesfor engine space are assu,ed to range fro, /G to &(4N$. "s the range ofchanges is so 9ide5 it is necessary to use se,iconductors designed for 9or;ing inhigher te,peratures and also to introduce te,perature co,pensation.

. "s the role of ,echanical vi-ration generated -y the engine and the syste,sconnected to it is very i,portant5 a lot of innovative solutions concerning the,ounting of engines and su-asse,-lies in the car -ody have -een 9or;ed out.

@hile driving on irregular surfaces5 shoc;s as strong as several do=en g 9ithfre7uency of up to hundreds of )= arise. Therefore5 li,iting the nu,-er of solderedconnections and protecting the syste, -y ,eans of elastic 6lling ,ass precludingvi-rations of particular su-asse,-lies is reco,,ended.

/. Electronic syste,s ,ounted in engine space are su-0ect to hu,idityresulting fro, condensation of vapour present in the air. @hen it rains5 they aresu-0ect to splashed 9ater and ,ud action. @hen the te,perature falls and airhu,idity is high5 de9 or hoar frost settle on car ele,ents. Besides5 the action ofsalt and acids causes corrosion da,ages. To avoid che,ical e8ect5 galvanic coatingsof ,etal ele,ents5 appropriate silicon-ased 6lling ,asses and airtight sealing ofsyste,s are used.

4. Ensuring high relia-ility in a long period of ,aintenance re7uires ta;ing intoconsideration the in


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Reliability of Combustion Engine Electric Equipment