2012 IACSIT Coimbatoe Confeences IPCSIT vol. 28 (2012) (2012) IACSIT Pess, Singapoe A Study on Senso Design fo Measuement of Automobile Engine Oil Degadation and Level Jaehwa Kim 1 and Sekwang Pak 2 + 1 School of Electical Engineeing and Compute Science, Kyungpook National Univesity 2 Depatment of Electical Engineeing, Kyungpook National Univesity Abstact. In this pape, the senso design was measuement of automobile engine oil degadation and level. The senso was designed fo the measuement of the change in capacitance accoding to the change of pemittivity between the electodes Degadation and level senso insulated fom each othe, egadless of the measue it was designed to be. Tempeatue conditions of the expeiments wee fixed between 79 and 81 fo consistent measued value. As a esult of the expeiments, afte consumption of blend additive to oil degadation, so vaiation of capacitance is 18.41 pf accoding to oil degadation. Sensitivity is 0.493 pf/mm accoding to change of oil level, and Eo is less than ± 0.227 pf/mm. Keywods: automobile engine oil; capacitive senso; oil degadation; level senso 1. Intoduction Automobile maket has been developed fo a convenient lifestyle of the moden society. Optimum timing of engine oil change is to pevent accidents of the engine, to save esouce and fo the potection of the envionment. Most of the engine oils ae based on mineal oil made fom petoleum though efining. It is fomed with a vey complicated molecula stuctue because of the addition of vaious additives in ode to impove this popety. Accodingly, vaious studies have been caied out to judge the oil state, and ecently the studies ae focused on a method which makes use of pemittivity, which is the electic popety of oils [1]. Engine oil foms a film on each moving section of the engine and cools off the fiction on the suface of pistons. It also pevents coosion and oxidation caused by condensation and combustion to ensue that the duability of the engine. Howeve, engine oil degadation and deceasing oil level can lead to an accident with the engine damage. Since 1980, when eseach on the life of oil began, a vaiety of methods fo measuing oil degadation have been intoduced [2-5]. Howeve, sensos can be difficult to develop accoding to the engine tempeatue, automobile leaning, and installation location. This pape is fo senso which consists of an aay of plates fo degadation and level measuement of the automotive engine oil. Senso was designed fo a limited space in the dain hole of the oil pan. Sensos due to suface tension by design; changes to emove oil tap phenomenon, and inceased sensitivity to oil degadation and to allow independent measuement of the level of the system was designed. 2. Pinciple of the engine oil degadation and level measuement 2.1. The pinciple of measuing degadation As the mileage inceases, the degadation, the initial popety changes and it makes pogess inside the engine due to the fomidably high tempeatue and pessue. Accoding to lubication and engine cleane by degadation, engine oil has deceased functions. Oxidation will occu accoding to the incease in coosion + Coesponding autho. Tel.: +82 53 950 5606; fax: +82 53 950 6600. E-mail addess: skpak@knu.ac.k. 11
and sludge. This phenomenon deceases the engine life. Key paametes of change engine oil degadation is TAN, TBN, viscosity, colo, content of wate and cooling wate. In geneal, degadation of the engine oil accoding to inceasing TAN, TBN will decease [5]. In this pape, oil degadation is detemined by measuing the change in pemittivity. When the cause of pemittivity change is analyzed to measue the oil degadation, it is identified that the oxygen compounds with oil solubility, such as ketene, aldehyde and alcohol ae geneated fist, and then they change into oganic substances like caboxylic acid and oxygen acid [6]. Such poducts ae pola molecules with acidity. As fo the elationship between the field stength E applied to the dielectic substance and the polaization P, the polaization gets bigge when the field stength inceases as shown in the equation (1). P = ε χ E (1) 0 e And the elationship, which is indicated in the equation (2), is established between the elative pemittivity ε and the electic susceptibility Xe, which epesents the degee of polaization caused by the electic field that is applied to a cetain substance. ε + =1 (2) χ e The deteioated oil with pola molecules appea to have a bigge electic susceptibility than the nondeteioated engine oil with non-polaization, and it is geatly affected by the metallic paticles and metallic ions that incease due to coosion and abasion. Accodingly, it can be identified that the moe the engine oil is deteioated, the moe the pemittivity of the engine oil is inceased. The change in capacitance value is based on the change in the pemittivity caused by the degadation of the engine oil (3). d C = ε 0 ε (3) A 2.2. The pinciple of measuing level Oil level deceases with the oil pan leak, damage of gasket and oil dain valve, evapoation accoding to oil degadation. In geneal, the oil pessue senso mounted on the dash by the pessue dop of the oil level waning lamp oil intake is lowe than the installed oil pan, o oil pessue is vey low opeation condition, if moe than about 5atm(pessue less than 0.5). When the lights tuned on, the dive stopped to check if the engine can lead to engine damage. The use can check the oil level with the use of a dip stick in the automobile bonnet. Howeve, the inspecto used cannot be tusted by taking a subjective view, eal-time monitoing is impossible. Engine oil level measuement is used to change of pemittivity of the dielectic ε [6]. In geneal, pemittivity of both ai and oil is eithe 1.00059 o 2.2. Capacitance s measuement with decease when exposed to ai and the senso is in the oil level. 2.3. Senso design The engine oil degadation and the level senso fo the measuement was poduced. The electode was poduced fo the defense of the FR-4 wap phenomenon at high tempeatue. Two sides of the Au electode wee poduced by electoless plating by using a thickness of 0.035 mm (Fig 1). The stuctue of the automobile opeates in such a way as to pevent damage due to the oil tempeatue, Teflon was used. In geneal, Teflon is limited the tempeatue above 350. The senso is suitable fo poduction. Also, by having a low pemittivity, the insulation between the electodes was pefomed. The senso was designed within the limited space in the dain hole of the oil pan. Tempeatue senso was designed fo package was to opeate at a fixed tempeatue. Theefoe, the pemittivity by tempeatue change was to ensue data eliability. 2.3.1. Plate type senso design Fig. 1: Senso electode design. 12
Electode gap to smooth the flow of oil to 0.6 mm was designed. Consideing the limited space of the oil dain valve, the ba stuctues wee poduced to the package stuctue. Capacitance was measued by inseting an electode between the stuctues. Lead fame was used to connect the electode. The electode wies wee connected fom the outside of the stuctue. Oil valve poceeded by theaded and eceptacle with plug made by combining ciculaly. A combination of the stuctues was used in the EPO-TEK to maintain a tempeatue of about 100 and was poduced by cuing fo 10 minutes in the oven. Figue 2 is a photogaph of the senso expeiments. Always measue the degadation of the oil fom the oil fom which the state is measued. Howeve, the oil and ai levels ae measued by the diffeence in the pemittivity. This is done by measuing the senso exposed to the ai by the pemittivity of the ai should be measued capacitance. Howeve, the senso electode is made up of a hoizontal aay and the oil tap phenomenon has occued. Poblem occus due to this phenomenon ove time, when oil is not emoved o if thee is a small impact of oil tapped due to the suface tension of oil is not emoved. 2.3.2. Slope type senso design Senso of slope was poduced to emove oil tap phenomenon due to suface tension. Plate fom the slope of the stuctue was emoved when the oil tap phenomenon was confimed though expeiments. Figue 3 of the electodes is the designed senso stuctue which is to have a slope of 30. Inceased sensitivity in the stuctue of the electode plate spacing was educed to 0.3 mm fom 0.6 mm and was poduced. Fig. 2: Oil tap phenomenon. Fig. 3: Fabication of engine oil degadation and level senso (A: stuctual design, B: poduction stuctues, C: tempeatue senso, D: electode fame, E: electode, F: senso packaging). 3. Expeiments and esults 3.1. Oil tap phenomenon Figue 4 is a gaph fo the confimation fo the emoval of oil tap phenomenon. The slope was an expeiment using a senso, the used oil is new oil. By diving the oil tempeatue was measued to be aound 79 ~ 81. By emoving the senso fom oil into ai ove time, a change in capacitance was obseved. Removal fom the oil senso was measued 15 minutes afte a apid decease in capacitance appeaed. The slope senso does not get the oil tap phenomenon, by heat the oil viscosity is loweed and the oil is emoved fom the senso. 15 minutes to 60 minutes afte emoval of the senso, change in capacitance is 1.1 pf. Theefoe, the oil senso is exposed to ai afte 15 minutes of emoval. 13
Fig. 4: Expeiment oil tap phenomenon 3.2. Expeiment conditions Degadation was measued on using the oil sample of fesh oil until the 10000 km. The oil gade used in this expeiment was 5W20 of SAE specification. And the oil was collected fom a gasoline automobile fo business use and mainly uns in the cities. Degadation and level senso wee insulated fom each othe; it was designed to be egadless of the measue. By measuing the suface tension of the oil tap phenomenon it was emoved fom the senso and then, afte 15 minutes it was measued. Using the hot plate the data was measued between 79 and 81 of oil tempeatue. In an expeiment, stiing at 500 pm in ode to pevent the pecipitation of coosive oil and the oil inside the oil pan to meet the expeiment was pefomed in ciculation. Fo the analysis, change in the capacitance due to input fequency; fequencies of 0.12 khz, 1 khz, 10 khz, and 100 khz is applied. Fo validity, the included eo in data measuement is moe than 500 times and sampling peiod was set to 5 seconds. 3.3. Expeiment esult Fig 5, 6 of the input fequency and mileage accoding to capacitance and esistance is a gaph of change. Capacitance and esistance values ae measued at 0.12 khz input fequency sensitivity which is the lagest Sensitivity is deceased accodingly by inceasing the input fequency. Mileage accoding to the capacitance and esistance chaacteistics of the opposite seems to change. This is due to oil degadation and oxidation is due to the change in oil popeties. Capacitance accoding to the oil and chemical degadation is caused by acid, is inceased. Accodingly, the capacitance and TAN (total acid numbe) is inceased [5]. In contast, esistance to the piston movement and sludge in the engine is due to the inceased mechanical changes caused by the alkali esistance of the mateial and the TBN (total base numbe) is educed. Sensitivity is the highest fo the input fequency fom 0.12 khz and to analyze this, the value is measued. Fou types of the highest in the new oil of the oil sample capacitance 88.4 pf value wee measued. Because the injected synthetic base oils and vaious additives is the initial capacitance. Subsequently, when oil is measued at 2000 km mileage 22.15 pf to 66.25 pf capacitance, make sue to decease. The initial additive oil is dispesants, pefume agents, antioxidants and the effect is due to the educed total acid numbe. Inceased mileage oil sample causes a continuous incease in capacitance, esistance is educed. At 7000 km, the oil sample capacitance epesents an incease fom 11.35 pf to 77.6 pf. Afte exhausting the initial additive degadation and oxidation by the TAN value, the capacitance inceased. At10000 km, the oil sample epesents a continuous incease, 84.66 pf wee measued. Since the depleted oil additives wee isen moe than 20 pf capacitance, it must be eplaced. In addition, it gives engine oil degadation to uses which will pevent accidents. 14
Fig. 5: change in capacitance due to fequency and mileage Fig. 6: change in capacitance due to fequency and mileage Fig. 7 is change of the capacitance to esult by oil level and input fequency 0.12 khz. Sensos have 85 mm electode length, and oil level is decision accoding to measuement of capacitance change by 10 mm unit. When in the ai of oil senso and the capacitance ae measued by making was ideal gaph. As a esult of the expeiments, be compaed to ideal values up to 0.227 pf/mm, at least 0.009 pf/mm have seen the eo and aveage eo is 0.088 pf/mm. sensitivity is 0.493 pf/mm accoding to changes of oil level. The change in capacitive shown at least 2000 km of mileage oil fom sensitivity 0.344 pf/mm. The senso was confimed that can measue 10 mm oil level though expeiment. 4. Conclusions Fig. 7: Change of capacitance due to oil level and mileage In this pape, the senso design was measuement of automobile engine oil degadation and level. The measued capacitance is inceased 18.41 pf due to oil degadation afte exhaustion of additives of oil. Saving was of the minimum value of capacitance by exhaustion of additives of oil. Due to the incease of mileage was measued by inceasing of the detemine oil degadation. Oil level is decision accoding to measuement of capacitive change by 10 mm unit. Measuement eo is less than ± 0.227 pf/mm and the change was of the minimum capacitance 0.344 pf/mm. The senso was confimed that can measue 10mm oil level though expeiment. Howeve, thee still emains the futhe woks to be supplemented, such as the minimizing the influence of output ipple of the pocesso that is designed to acquie the stable esult values, and the test in which the senso is installed in actual vehicles though miniatuization of the cicuit. 5. Acknowledgements This wok (Gant No. 00047956) was suppoted by Business fo Coopeative R&D between Industy, Academy, and Reseach Institute funded Koea Small and Medium Business Administation in 2011. 6. Refeences [1] Simon S. Wang, Yingjie Lin, A new technique fo detecting antifeeze in engine oil duing ealy stage of leakage, Sensos and Actuatos B: Chemacal, Vol 96, 2003, pp. 157-164. 15
[2] G. N. Mills, measusing the debis, Industial Lubucation and Tibology. Vol. 37, no. 1, 1985, pp. 176-183. [3] Masom. R. A. The development, poviding and application of an in-line metal patcle detecto(mpd), Bitish jounal of Non-destuctive testing, 1985, pp. 159-166. [4] D.J. Smolenski, S.E. Schwatz, Automotive Enfine-Oil Condation Monitoing, Handbook of Lubication and Tiboligy, Vol. Ⅲ, 1993, pp. 17. [5] R. Thom, K. Kollmenn, W. Wanecke, M. Fend, Extended Oil Dain Intevals: Consevation of Resouces o Reduction of Engine Life, SAE Technical Pape 951035, 1995. [6] Simon S. Wang, Road tests of oil condition senso and sensing technique, Sensos and Actuatos B: Chemical, Vol. 73, 2001, pp. 106-111. [7] A. Agoston, C. Ötsch, B. Jakoby, Visconsity sensos fo engine oil condition monitoing-application and intepetation fo esults, Sensos and Actuatos A: Physical, Vol. 121, 2005, pp. 327-332. 16