It exists, but has a value of 0 which cannot be changed.
There is at the menu (for the TOD value context) and from “?timeof”:
e_TimeOfDay = 7.3 
e_TimeOfDayDebug = 2 
e_TimeOfDaySpeed = 0 
sv_timeofdayenable = 0 [DUMPTODISK]
sv_timeofdaylength = 1 [DUMPTODISK]
sv_timeofdaystart = 12 [DUMPTODISK]
None of the e_* values can be changed, and I noticed no difference from experimenting with variations on the sv_ ones even with a restart.