Aspects about estimation of replacement moment at lubricate oils for spark ignition engines.

Ungur, Petru ; Pop, Adrian Petru ; Veres, Eugen Mircea 等

Abstract: The paper has presented aspects about moment estimation of lubricate motor oils replacement, a method and determination installation. The method is practical and has at base ball method and cylinder, consisted in fall timing of a steel ball with diameter of (2.5-3.2)mm inside of special graduate cylinder in which is get in the oil of test. The new of installation consisted in that an electronic assembly with photoelectric cell, magnetic and temperature sensor does fall timing of steel ball. The installation can be simple by application of Hall Effect.

Keywords: ageing, attrition, lubricate, oil, replacement, wear.

1. INTRODUCTION

In practical, the most used lubricate is multi-grade mineral oil for engines automotives. The mineral oils for engines are get by oil distillery of extract fractions lubricates from crude oil. The main role of mineral oil for engines has as principal function of hydrodynamic liquid lubricate of parts with active surface in relative motion, example piston-cylinder mechanism are characterized from viscosity, unctuously, density, specific warm, thermal points of freezing and inflammation, quantity of water, ash and mechanical impurities. In operating of spark ignition engines the property of lubricates oils is alter by them degradation in time, being necessary them replacement.

In general, engine oils can be replacement at different cycles of running by automotives (10000, 15000, 30000km) in function of type of engine, oil and normal mode running.

At an intensive running of engines, the mineral oil's degradation is excessive, being required an estimation of moment for the replacement of oil.

This paper has presented some estimation of time replacement of oil with an operative and practical method and a measure installation, which is simple and easy of operation.

2. QUALITY AND ESTIMATION OF MINERAL OILS

The engine oils is chosen in such away that them accomplished the lubricate functions, keeping initial physicchemical properties for a long time of running engine, being less sensible at variation of environmental temperature and relative cheap [Chisu,1981;Popa,1982].

The physic-chemical and working properties of oils and methods of determination are given by rules and standards [Rufe,2002] for each item, as: Density of 150, Point of inflammability-0C, Cinematic viscosity-at 500C and 1000C, Index of viscosity-AD, Point of freezing, Organic acidity-OH mg/Oil g, Mineral acidity and alkalinity, Content of water, Mechanical impurities-%, Ash, Foam tendency, etc.

The functional properties of mineral oils [Manea,1970; Pascovici,1985] have characterized them behavior in friction process of metallic surfaces in relative moving have divided in two main groups: lubricate properties and physic-chemical properties that has characterized operating. First group are antiwear and anti-friction properties and second-viscosity, emulsionability, foaming, corrosively.

[FIGURE 1 OMITTED]

In function of friction's conditions, for characterized of engine oils are determined following properties: viscosity for hydrodynamic lubricate and EHL conditions, unctuously and adhesion properties for limit condition, chemical action of oil for friction condition, which destroyed lubricate film (fig.1).

The real importance of viscosity size has given by starting and running engines, attrition gradation of parts with active surface in contact or in relative moving. So at fast start of engine is required a smaller viscosity of mineral oils, in running a normal viscosity and for a worn engines a higher viscosity.

At new engines are required oils with best properties of unctuously and anti-sticking additives.

The contamination of oils was influence by using in good condition of oil filters. In addition, consumption of oil is dependent of engine condition and its wear parts and oil's properties. A great consumption of oil at engines is determined even uptightness, which able penetration of oil in burned chamber. The normal oil consumption for spark ignition engines is (0.2-0.3) l at 1000km running [Popa,1982].

The extra consumption oils is get by: large clearances at mounting parts, great attrition of parts from piston-cylinder group, wear of some parts in relative motion, incorrect adjustment of lubricate mechanisms, using of oils with inadequate viscosity. Inadequate running of engine and higher revolution speeds due to a great consumption of oil. Thus, it has become a priority determination of replacement moment of engine oil and oil completion.

From analyze of flow viscous mineral oils has observed that in first phase of its using are corresponding Newton Law, which linked unitary tangential effort of speed gradient:

[MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII] (1)

Where: [eta]=viscosity coefficient, [DELTA]D=distortion gradation, [DELTA][tau]=time range, a=relative distortion, [eta]'=speed of relative distortion.

After a great number of running hours at spark ignition engines is appeared oil contaminations with impurities, forming a suspension, which due to thickening of system by rise viscosity.

In this phase the exhausted lubricate oils has behavior after elevation law:

[sigma] = k[([gamma]').sup.n] (2)

[eta] = k[([gamma]').sup.n-1] (3)

Where: k=is a constant, n=exponent and show oil behavior: for n=1-Newton's liquid, n>1-dilated liquid and n<1 pseudo-plastic liquid.

Completion of lubricate oils and them mixed (exhausted oil with new oil) is located the mixture in an intermediary position with a middle viscosity. The mode of behavior engine oils has realized with consecrate lab methods, which are expensive and require skilled labors.

3. METHOD OF ESTIMATION REPLACEMT MOMENT OF ENGINE OIL

In practice is used a lot of operative methods for determination of replacement moment of engine oil [Pavelescu,1977; Pascovici,1985], as microscopically method, photo-electrical method and method of contact spot oil, which have disadvantage that are less accurately.

An efficient accuracy method and a new device used for estimation of replacement moment of engine oil will be present in this chapter, being a modernization of method with ball and cylinder [Ungur,2007].

The method consisted in timing fall time of steel ball with a given diameter-d1 on a distance-l1, within a graduate cylinder from transparent plastic with inner diameter-d2 that is greater as ball diameter, and having a length-l2, greater with at less of 1/3 x l1, inside is get in the oil of analyzing.

Installation presented in fig.2 has composed from: 1support from plastic in U-shaped, endowed with a magnetic sensor-2, positioned in inferior side of support, inscribed in closed electric circuit supplied by an alkaline baterry-4. On one side-b of support-1 is mounted a photoelectric cell-5, and on opposite side-c a light source-6.

The side hands-b and c and flat bottom-d of support are contained graduate cylinder-7 from transparent plastic, in which is get in engine oil of analyzing under of index level-e, that are monitories by a light beam emission by bulb-6 and has collected by photodiode-5.

Inside of electrical circuit of photodiode is introduced a galvanometer-8, on which is pass through a current which is higher with what the light flux is more power, amplified by an amplifier-9.

[FIGURE 2 OMITTED]

At get in of steel ball in a cylinder, during its touch of oil surface is blocking beam light emission by bulb, which drop on photoelectric cell, in this case, it has not lighted due to close the current in circuit of amplifier and signal the start moment-ti of drop in mass of fluid.

In function of density and viscosity of oil the steel ball touching the bottom of cylinder at a moment-tf, signal by an electro-magnetic sensor-3, has attracted by ball, which close electrical circuit-10.

The temperature of oil has taken by sensor of temperature11 with a separate electrical circuit-12. The index of apparent viscosity has determined with relation:

[i.sub.va] = [DELTA][t.sb.u]/[DELTA][t.sub.i](4)

Where: [DELTA][t.sub.u]-is temporal difference of drop ball in sample of used oil, and [DELTA][t.sub.i]-temporal difference of drop ball in sample of new oil.

The on coming or go away from the unit of apparent viscosity ([i.sub.va] [less than or equal to] 1), due to a fast estimation of replacement moment of exhausted engine oil.

4. CONCLUSIONS

The new installation presented is simple and easy using. Method and installation with ball can be using at quality estimation of transparent liquid viscous fuels as type of gas oil and black crude oil in conformity with standards, in this case plastic graduate cylinder has unique used, with possibility of capsulation and label as master tests.

The installation presented can be easy connection to PC by an interface and electronic circuits with acquisition data and software, which improved quality measures.

This installation can be simplified by application of Hall Effects, which representing the next theme of research for authors.

5. REFERENCES

Chisu, A., & al. (1981). Elements of Machines, Didactical and Pedagogical Editor, Bucharest.

Manea, G. (1970). Elements of Machines, Vol. I, Technical Editor, Bucharest

Pascovici, D.M. (1985). Lubrication, Present and Perspectives, Technical Editor, Bucharest.

Pavelescu, D, Muset, M., Tudor, A. (1977). Tribology, Didactical and Pedagogical Editor, Bucharest

Popa, B. & al. (1982). Engines for Automotives, Dacia Editor, Cluj-Napoca, Romania.

Rufe, P. (2002). Fundamentals of Manufacturing, Society of Manufacturing Engineers Editor, ISBN-087263524-4, Dearborn, Michigan, USA.

Ungur, P.; Pop, P.A.; Gordan, M., Caraban, A. (2007), Industrial Wastes Using For Green Cleaning Of Lubricant Oils of Exhausted Motor, Proceeding of International Scientific Conference microCAD 2007, 23-27 March 2007 Miskolc, pp.155-160, ISBN 978-963-661-742-4 O, ISBN 978-963-661-744-8, Innovation and Technology Transfer Center and University of Miskolc Publisher.

Ungur, P.; Pop, P.A.; Gordan, M., Veres, M. (2007), Some Aspects About Construction Of Mono-block Ecologic Filters for Exhausted Drums, Proceeding of International Scientific Conference microCAD 2007, 23-27 March 2007 Miskolc, pp.155-160, ISBN 978-963-661-742-4 O, ISBN 978-963-661-744-8, Innovation and Technology Transfer Center and University of Miskolc Publisher.