Your bodies pH level could be off, alkaline and acidic levels. The pH of your body fluids has to be regulated in the range 7.35 to 7.45, deviations outside this range affects normal functioning cells and body systems. With a strong ammonia odor, this could be corrected by eating more red meats, foods high in protein. You may not be drinking enough water. Then again, it could be the onsight of a urinary, bladder, or kidney infection. Consult your physician on your individual case.
I forgot to mention that an improper pH balance will cause headaches, low energy, and a poor ammune system. You can buy pH test strips at your local Rx.
Urine is high in nitrates, compounds high in nitrogen and oxygen. Ammonia is made up of nitrogen and hydrogen. (NH3) What you are smelling is the high concentration of bonded nitrogen.
Normally, diluted urine doesn't have much odor. If you're dehydrated and your urine becomes highly concentrated, it can have a strong ammonia smell.
As a general precaution, If you are smelling ammonia in your urine, it would not be a bad idea to go to your general practitioner (family doc) and have a hepatic function panel done to rule out serious liver issues.
In our urine, Ammonia acts as an absorber and leads to water absorption.
There is a mistaken belief that the ammonia can be attributed to a lack of protein.