In autumn 2015 VMPAUTO company started oil sampling from modern car Range Rover – turbodiesel, 3-liter, 298 HP. The taken oil - Castrol Edge 5W-30 Titanium Professional A5.
The oil was taken from the bottom of the pallet into a special sterile container and, surprisingly, metal particles were discovered there.
We took oil samplings through various mileage intervals: 0 km, 1000 km, 1500 km, 3000 km. Each oil sample we tested under standard conditions on the friction machine. Clean oil showed excellent performance and full-time working temperature of 100'C, but after only 1,000 km the same oil showed operating temperature of 130'C. After another 500 km oil has already worked at 170'C. At run 3,000 km oil showed an operating temperature 180'C. Tests were conducted under the same conditions.
The next step of our experiment was the measurement of HTHS (High Temperature, High-shear rate viscosity) of oil. The peculiarity of this parameter is that it is measured at very high shear rates of oil film. It is important not to confuse the oil film shear rate and movement speed of the piston.
Shear rate is defined as the ratio of movement speed of the layer to its thickness and its dimension is in sec-1. So, if we divide meters / second to meters, we will get sec-1, and HTHS viscosity has the dimension in Pa*sec.
There is a special device which we use to create the same load as in the engine to determine HTHS-viscosity. This is important because HTHS is the parameter that determines characteristics in working conditions, right exactly what is happening with the oil film between cylinder wall and piston ring while driving at very high shear at a temperature of 150'C.
Our experimental oil l5w-30 showed different viscosity rates during the experiment: clean oil showed the desired viscosity -- a little more than 30. After 1000km of run there was some increase in viscosity. Most likely, this was due to the particles of soot that got inside, since it is primarily the reason of increasing viscosity of oil. After 1500 km of run viscosity was at the lowest line of SAE standard.
The main reason of oil dilution is ingress of fuel. Especially of diesel fuel (gasoline evaporates easier and often without any consequences). Soot also may affect the quality of oil: its viscosity is maintained by special molecules which roll up at high temperatures and thus increase the viscosity. But if a lot of soot particles sit on the rolled up molecule then the molecule won’t shrink further, it will no longer work. However, the main factor that affects oil viscosity is fuel.
Modern engine looks like the system of treatment facilities. Including particulate filter which cleans the exhaust gases from soot.
Normal exhaust temperature is 350'C. But for regeneration of the particulate filter gases warm up to 600-700'C that allows to turn the soot particles into carbon dioxide. This procedure takes place in the car every 400-600 km. In order to warm up the gases to the required temperature, an additional amount of fuel is injected into the combustion chamber. This excess fuel burns down in the filter.
Surely engine life will be reduced but the environmental issue is a priority.
There is a class of substances such as oil thickeners. They are distinguished from HTHS-viscosity stabilizer iMagnet P14 by parameter that they go beyond optimum - they make the oil too viscous. iMagnet P14 with surgical precision recovers oil characteristics and protects the engine.
To see what iMagnet gives in practice, we’ve tested this product on Range Rover. We have found that loss of viscosity led to loss of power and torque. The loss was about 30%.Which means that if the engine should produce 600 newtonian/ meter, then in practice it showed 500 newtonian/ meter. And the power was obtained of 220 HP when it should be 298 HP.
First of all HTHS-viscosity stabilizer is needed by vehicles with modern engines, with particulate filter regeneration systems. In addition, the deal is compounded by the use of energy-efficient oils since they have less margin of safety.