Assessment of low-viscosity oil performance and degradation in a heavy duty engine real-world fleet test

Abstract

Low viscosity engine oils (LVO) are considered one of the most interesting solutions for improving fuel economy in internal combustion engines (ICE). There are different studies involving LVO and ICE, but currently limited data are available regarding "real-world" performance of LVO in a real service fleet. Included in a broadest study related with fuel consumption saving effects and performance of LVO in a real service fleet, the aim of this work is to present the results obtained in terms of comparative oil performance.So, on this test, a comparative analysis using 39 buses was performed, based on a deep and extensive oil analysis program to assess those aspects above mentioned. Two engine technologies (Diesel and CNG) were considered and four different lubricants, two of them LVO and other two used as a reference baseline. The test duration comprised two oil drain intervals of 30000 km each one, totalizing more than 2 million of kilometers accumulated.Results have shown that LVO presented an excellent performance along the oil drain interval (ODI), even improving some characteristics of the baseline oils with higher viscosity values. Results have shown that oil degradation is more dependent on engine technology, but in any case presented a penalization in terms of ODI reduction, a key indicator for end-users related with maintenance costs. In the case of CNG engines, higher oil degradation in terms of oil oxidation and nitration was observed.

Study on comprehensive degradation stability of special and nonspecific motor oils

“…Oxidation stability considers as one of the most important parameters of lubricating oil to evaluate the service life in high temperature and extreme applications. [8][9][10] There are some commonly used methods to evaluate the oxidation stability of lubricating oil, such as rotary bomb oxidation test (RBOT, ASTM D2272), 11,12 oxidation stability test (ASTM D943), 13 FTM 791-3462 coking test, differential scanning calorimetery (DSC)/ PDSC (ASTM E 2009-02), 14 and so forth. Santos et al 15 studied thermal oxidation stability of synthetic oils which aging at different temperature and time with TG and DSC.…”

Condition Monitoring with Prediction Based on Oil Engines of Urban Buses – A Case Study

“…Test results confirm that the use of LVO could reduce fuel consumption, hence CO2 emissions. However, special attention should be taken prior to its implementation in a fleet, particularly if the vehicles powered by engines with high mechanical and thermal stresses during vehicle operation because this could lead to friction loss increase, loss of the potential fuel consumption reduction of LVO and, in the worst scenario, higher rates of engine wear [14].…”

A field test method to quantitatively determine oxidation stability of gasoline engine oil

“…The more resistant a lubricant is to oxidation, the less tendency it has to form deposits, sludge, and corrosive by products in industry application . There are some commonly used methods to evaluate the oxidation stability of lubricating oil, such as rotary bomb oxidation test (RBOT, ASTM D2272), oxidation stability test (ASTM D943), FTM 791‐3462 coking test, and differential scanning calorimetery (DSC)/PDSC (ASTM E 2009‐02) . In RBOT test, a 50‐g sample plus a 5‐g amount of water and a high‐purity (99.9%) copper coil are placed in a beaker and loaded into a pressure chamber, sealed and then filled with 99.5% pure oxygen gas at a pressure of 0.62 MPa, and the entire pressurised chamber is rotated in an oil bath at 150°C.…”