An antifreeze is an additive which lowers the freezing point of a water-based liquid. An antifreeze mixture is used to achieve freezing-point depression for cold environments and also achieves boiling-point elevation (anti-boil) to allow higher coolant temperature.
The strains of virus the trivalent vaccine protects against two A viruses (an H1N1 and an H3N2) and an influenza B virus. The quadrivalent vaccine adds another B virus to the vaccine which helps expand the level of protection to the recipient.
If there is a lot of drift in predominant strains, the vaccine will not protect as well in that year. Certainly the presence of a fourth strain should be helpful in that regard (note that the trivalent vaccine always covers two influenza A and one influenza B every year; quad covers two A and two B).