Heavy duty diesel engine oil additives

Friction modifiers for heavy duty engine oils 

Friction modifiers and other additives are included at much higher treat rates in HDDEOs compared to passenger car engine oils. The additive content can be almost double that of passenger cars and dispersants and detergents perform a greater role.

Whilst friction modifiers have not been an area of focus for HDDEO until recently, they now play an important part in very low viscosity oils to reduce wear and friction. 

To study the activity of our friction modifiers in HDDEO and their propensity to lower the coefficient of friction, we tested them in top-treated commercially HDDEOs. 

Friction modifier performance in a commercial 15W40 HDDEO

We used a mini traction machine (MTM) to evaluate frictional performance under constant load and temperature. Results (Figure 1) were taken after the oil was aged in the test for two hours, to allow time for full film formation. 

After two hours, it was found that Perfad™ 3050 offered a 70% reduction in friction coefficient in boundary regime conditions versus the neat oil. In this case, different additives did not lead to similar reductions in this formulation. 

This test demonstrates the importance of testing additives extensively before approval and the friction reduction potential of friction modifiers in HDDEO formulations. Our application scientists can help you select the correct additives for your system and save you time by helping you devise test programs that are representative of the materials tested. 

Figure 1: Stribeck curve demonstrating friction modifier performance after two hours of ageing in a 15W40 HDDEO 

Base oil selection for heavy duty engine oils 

HDDEOs are moving to lower viscosity grades (<5W-30) as newer engines are designed to operate with lower viscosity oils to reduce drag and improve fuel economy. 

As hydrodynamic thin-film lubrication is the main operational regime of heavy-duty engines, it is a common view that base oil selection is key in obtaining more efficient lubrication and fuel efficiency. 

Formulating ester base oils into low viscosity engine oils allows the formulator to achieve higher viscosity index and obtain a low NOACK volatility at the same time. Further, esters are excellent solubilisers and can improve the detergency and dispersancy performance of the final formulation.

REWITEC™ Powershot™ surface repair additives in heavy duty diesel engine oils 

After 40 hours of running the damaged camshaft sample on the 2-disc assembly, visual signs of damage had been reduced and a reduction in friction was quantified. 

 

Figure 2: Wear scar resulting from 2-disc assembly before and after REWITEC application

Figure 3: Quantitative output from the 2-disc rolling wear test demonstrating friction reduction with the addition of REWITEC technology.

Whilst we recommend further testing in your own system, this simple example demonstrates a reduction in friction and signs of visual wear using a commercial HDDEO and REWITEC silicone additive technology.