Necessary of Nano lubricants in in Engine performance and cold start
application
To understand the usefulness of nano lubricants, after studding previous papers, it has found
that use of nano particle highly influence the engine performance at different temperature
condition. Some step wise discuss, why we use nanoparticle or nanolubricants are below.
 The main attribute of nanoparticles is that they have closed structure, which is minimize
the number of dangling bond. The reason, they are not much chemically reactive than
conventional additives and compound. Another benefits of their size and morphology
that is cylindrical and spherical shape can allow them to easily penetrate the contact
zone of friction that provide good tribological property and produce a thermal barrier
help in cold start application.
 From Mohammad Hemmat Esfe et.al they also found that use of hybrid nanofluid that
is viscosity of MWCNT-ZnO (20%-80%)/5W50 nano oil with MWCNT-Al2O3(35%65%)/5W50 nano oil and 5W50 base oil was done in thir paper. Curve of viscosity
versus temperature in shear rate of 3999 (1/s) and solid volume fractions of 0.05% and
0.25% are depicted in Figure.
From the figure, it’s noted that the nanolubricants prepared by researchers has shown effective
result at low temperature. The engine will not damage due to insufficient flow of lubricants
and damage of parts as well. So, to maintain proper viscosity at low temperature it’s efficiently
reported. They also optimized the temperature, solid volume fraction and share rate to select
proper nano oil for cold start application.
Table: Indication of viscosity changes for choosing proper engine oil for cold start
Solid
volume
fraction
1
0.75
0.5
0.25
0.1
0.05
Temperature
Viscosity(mPa.sec)
Viscosity
Enhancement
shear
rate(1/sec)
5
5
5
5
5
5
656
615
574
566
529
525
13.49481
6.401384
-0.69204
-2.07612
-8.47751
-9.16955
666.5
666.5
666.5
666.5
666.5
666.5
 Mohammad Hemmat Esfe et.al also depict same result in their another study in 2018
by using RSM and ANN analysis. They try to show how accurately nanolubricants
effects on very low temperature and lower the viscosity.
 Mohamed Kamal Ahmed Ali et.al provide performed on gasoline engine (model
HXDG16-BD-TJ, multi-point injection, independent ignition, water cooled, and a
naturally aspirated). The engine is prepared with AVL dynamometer for measuring the
engine performance.
Again on this paper various aspect analysis has been done by researcher. The effect of
Al2O3/TiO2 hybrid nanolubricants on the warm-up phase (cold-start) when operating under
12 Nm and 1500 rpm. As a general trend, it is apparent from the investigation that the lubricant
temperature increased with rising the warm-up period for both nanolubricants and
nanoparticles-free lube oil. The results elucidated that the temperature for nanolubricants is
higher than lube oil without nanoparticles. This is related to the higher thermal conductivity of
the nanolubricant, which leads to higher rate of the heat transfer.
The Al2O3/TiO2 nanolubricant accelerate the warm-up phase by 24% at same operating
conditions due to improving the sensitivity of the lube oil to temperature. As a consequence,
the reduction in fuel consumption by 4–10% was obtained.