Changes of engine oil flow properties during its life cycle

Evaluation of motor oils is given a big attention due to a fact that during the years it was proven that lubrication is a key factor influencing a service life of vehicles and industrial engines. Motor oil must fully serve in various operational conditions (such as city traffic with frequent braking and acceleration) as well as in different climatic conditions (arctic winters or tropical summer heat). Therefore, the change of the motor oil should be optimized in order to ensure proper engine efficiency and extend its service life. The article presents result of testing of two types of used motor oils with the same specification ACEA E4/E7, SAE 10W-40, from two different suppliers. These oils were used in a high-volume diesel engine of IVECO CITY BUS. The sales representatives recently offered a more expensive motor oil (in the text marked oil B) claimed that in their oil can extend the change interval from 40,000 km to 80,000 km. Evaluation of selected parameters did not prove that after exceeding of change interval 40,000 km, the more expensive motor oil would ensure all required functions as it had been declared by the supplier's sales representative.

Section: Introductionmentioning

confidence: 99%

Definition of a Motor Oil Change Interval for High-Volume Diesel Engines Based on its Current Characteristics Assessment

Sejkorová¹,

Hurtová²,

Glos³

et al. 2017

Rheological profiles of blends of the new and used motor oils

Kumbár¹,

Polcar²,

Čupera³

2013

Self Cite

KUMBÁR, VOJTĚCH, POLCAR ADAM, ČUPERA JIŘÍ: Rheological profi les of blends of the new and used motor oils. Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis, 2013, LXI, No. 1, pp. 115-121 The objective of this paper is to fi nd changes of a rheological profi le of the new engine oil if the used engine oil will be add. And also fi nd changes of a rheological profi le of the used engine oil if the new engine oil will be add. For these experiments has been created the blends of the new and the used engine oil. The temperature dependence of the density [kg.m ] has been measured in the range of −10 °C and +60 °C. The instrument Densito 30PX with the scale for measuring engine oils has been used. The dynamic viscosity [mPa.s] has been measured in the range of −10 °C and +100 °C. The Anton Paar digital viscometer with the concentric cylinders geometry has been used. In the accordance with the expected behaviour, the density and the kinematic viscosity of all oils was decreasing with the increasing temperature. To the physical properties has been the mathematical models created. For the temperature dependence of the density has been used the linearly mathematical model and the exponentially mathematical model. For the temperature dependence of the dynamic viscosity has been used the polynomial 6 th degree. The knowledge of density and viscosity behaviour of an engine oil as a function of its temperature is of great importance, especially when considering running effi ciency and performance of combustion engines. Proposed models can be used for description and prediction of rheological behaviour of engine oils.

Analysis of Degradation of Motor Oils Used in ZETOR Tractors

Sejkorová

Glos

2017

The durability of motor oil and then the change interval are influenced by numerous factors and it is not easy to determine optimal mileage for a specific means of transport or a machine. The manufacturer proposes a maximum limit, but it is not always suitable since operating conditions influence the process significantly. Using FTIR spectrometry and analytical ferrography methods we evaluated used motor oils collected from older types of ZETOR tractors. Change intervals were extended for most tested oil fills. The analysis results showed that when the tractors were exposed to a considerable everyday load during autumn tasks, the lubrication and friction processes in their motors were affected negatively which resulted in increased wear. Therefore it is not advisable to extend the change interval as proposed by the ZETOR manufacturer.