Hybrid vehicles are a bridge to the future, a natural step in the evolution from internal combustion engines (ICE) to full batter electric vehivles (BEVs). Industry organizations, such as the API New Energy Vehicles Fluids Workgroup and the ACEA Future Tasks group, are looking into the need for new tests and specifications for hybrid vehicles. Though OEMs are currently recommending standard passenger car motor oils for their hybrid models, Chevron Oronite's research suggests that hybrid engines can benefit from specialized solutions that are designed to perform in their operating environment. Demand for hybrid-specific solutions is likely to grow as hybrids evolve and comprise a bigger percentage of vehicles on the road.

The internal combustion engine (ICE) component of a hybrid electric vehicle shuts down while the battery powers the vehicle. When this happens the average engine oil temperature is approximately 25% lower than an equivalent ICE. 

Plug-in hybrid vehicles (PHEVs) require the ICE to run infrequently and at a lower temperature than a conventional ICE. When the engine oil does not reach its normal operating temperature, there is an increased chance of water condensation from the engine blowby and higher levels of fuel dilution into the crankcase, creating engine oil emulsion that can impair lubricant performance and raise the risk of rust, corrosion, and increased sludge formation.