Greases for electric vehicles: a drastic reduction of bearing friction torque by a non-halogenated ionic liquid additive

• Due to their advanced tribological and electric properties, ionic liquids (ILs) are seen as potential lubricant additives in emerging green technologies. To verify their potential in complex machinery, an evaluation of tribological performance at the component and machine level is necessary. This work presents the effect of using a non-halogenated ionic liquid as a grease additive in bearings operating under driving cycle conditions. These harsh conditions are designed to be analogous to what a grease-bearing system must endure in an electric vehicle motor. One-month experiments, equivalent to 23,000 km of vehicle operation, were used to evaluate grease additive performance. Our results reveal that the addition of the ionic liquid resulted in a high-impact improvement, reducing bearing friction losses by up to 45%. Grease rheology and surface wetting measurements indicate that the sharp drop in friction torque is related to a complex balance of factors that results in a limited amount of highly effective lubricant products at the contact inlets (optimum degree of starvation).

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Maskinteknik -- Tribologi (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Mechanical Engineering -- Tribology (hsv//eng)

Nyckelord

Non-halogenated ionic liquid

Ionic materials

Friction torque

Electric vehicle

Additives

Grease lubrication

Machine Design

Maskinkonstruktion

Publikations- och innehållstyp

vet (ämneskategori)

ovr (ämneskategori)