To obtain a functional fluid composition excellent in abrasion resistance, extreme-pressure property and adaptability to seal and suitable for internal combustion engines regardless of low phosphorus level by including a specific thiocarbonate and a specific acylated nitrogen containing compound.
This functional fluid composition comprises (A) a compound of formula I [R1 to R2 are each H or hydrocarbyl; X is O or S; (n) is 0-2; T is hydrocarbyl, a hetero group, hydroxyhydrocarbyl, etc.] and (B) an acylated nitrogen-containing compound having a substituent group of ≥10 carbon atoms. Furthermore, the composition preferably further contains a phosphorus-containing compound, etc., a compound of formula II [T1 and T2 are each R, OR, SR or NRR; R is a hydrocarbyl; X1 and X2 are each O or S; (n) is 0-3], etc.
MANKA JOHN S
ABRAHAM WILLIAM D
ROBY STEPHEN H
