The two-dimensional CGHS model provides an interesting toymodel for the study of black hole evaporation. F or this model, a quantum eective action, which incorporates Hawking radiation and backreaction, can be explicitly constructed. In this paper, we study a generalization of this eective action. In our extended model, it is possible to remove certain curvature singularities arising for the original theory. W e also nd that the ux of Hawking radiation is identical to that encountered in other two-dimensional models.