Hello kanagala.
Mechanical engineering deals with core concept of heat, energy, fluids, machines, cad, cam and so on
Automobile engineering deals with the core concept of automobile parts and their design.
The tool engineering deals with the tools, their design, their air parameters and so on
Mechatronic Engineering deals with concept of manufacturing in mechanical engineering and the concept of circuits of electronics engineering.

All the above engineering courses have equally good scope and have equally high market share. It all boils down to your interest. So, select a stream according to your strength and interest.

All the best.