Tribochemical interaction of newly developed organic lubricant additives with ZDDP; the influence of organic additives on tribological performance of ZDDP

Reduction in fuel consumption and tighter environmental restrictions on the combustion emission products are among the key challenges of automotive industry, which can be partially addressed by developing more efficient, environmentally friendly lubricant additives. Zinc dialkyldithiophosphate (ZDDP) and friction modifier (FM) are considered as the most important lubricant additives for the tribological performance under boundary lubrication condition. ZDDP is an effective anti-wear (AW), anti-oxidant (AO) and extreme pressure (EP) additive but presence of ZDDP in engine oil increases the engine friction and have negative impact on the fuel economy. Organic friction modifiers (OFMs) are environmentally friendly lubricant additives, which have the capability to reduce boundary friction and improve lubricity by reducing the friction coefficient and contributes to improve the fuel economy. However, the performance of ZDDP in reducing wear is remarkable but it is established that the AW capability of ZDDP is compromised with the addition of OFMs in the lubricant blend. Result showed that the AW behaviour of ZDDP swings significantly from substantial increase to remarkable decrease in wear factor value.