keeping the screen on

Hi,

I have an android device and cannot seem to find a setting (both on my mobile device and on the app) that keeps the screen on while playing via Bluetooth in my car. The screen automatically goes black after a certain amount of time and I then have to try unlock and then go into the app while driving. Please help. There are no settings on android as suggested in previous answers - nothing under display and the lock screen only deals with the password to unlock your phone.