The Quran does not mention Ishmael…here are the quotes:
“O my Lord, grant me a righteous (son)!” So We gave him the **good news **of a boy ready to suffer and forbear. Then when (the son) reached (the age of) (serious) work with him, he said, “O my son, I see in a vision that I offer thee in sacrifice. Now see what is thy view!” (The son) said, “O my father, do as thou art commanded. Thou will find me if Allah so wills one practicing patience and constancy!” So when they had both submitted their wills (to Allah) and he had laid him prostrate on his forehead (for sacrifice), We called out to him, “O Abraham, thou hast already fulfilled the vision!” Thus indeed do we reward those who do right. For this was obviously a trial – and We ransomed him with a momentous sacrifice. 37:99-107
Has the story reached thee of the honored guests of Abraham? Behold, they entered his presence and said 'Peace!" He said “Peace”. … They said, “Fear not,” and they gave him **glad tidings of a son **endowed with knowledge. But his wife came forward (laughing) aloud! She smote her forehead and said, "A barren old woman! " They said, “Even so has thy Lord spoken: and He is full of wisdom and knowledge.” 51:24-25, 28-30
Peace and salutation to Abraham! Thus indeed do we reward those who do right. For he was one of Our believing Servants. And We gave him the **good news of Isaac **- a prophet - one of the righteous. We blessed him and Isaac. 37:109-113
Regarding the Islamic scholars, some believe it was Isaac, others Ishmael.
When i say, when ye in doubt, refer to the people of the book