What do you mean "engine"?
KMath is just a library that solves some mathemtical computational problems. As an example, it can find derivative of a function, but it cannot solve polynomial (systems of) equations.
Usually, programs, that solve such problems, are just piles of heuristics that can solve some small subset of all possible math problems. And usually, they are proprietary.
If you have an algorithmic way to solve some set of nath problems that you would like to implement, you can
create an issue in KMath repo on GItHub. And there is a chance it will be added into KMath.