Genesis 48:16

be pleased that the angel whom thou didst ordain for me, to redeem me from all evil, may bless the children; and let my name be called upon them, and the names of my fathers Abrabam and Izhak. And as the fishes of the sea in multiplying are multiplied in the sea, so may the children of Joseph be multiplied abundantly in the midst of the earth.

AND LET MY NAME BE CALLED ON THEM. Rabbi Abraham ibn Ezra said that it means that all Israel be called by the name Ephraim, (Jeremiah 31:19), the reference there being to all Israel. just as they are called “the children of Abraham, Isaac, and Jacob.”
This is not correct for Scripture uses the word bahem (on them), [thus referring to both Ephraim and Menasheh], and they were not called by the name of Menasheh. But perhaps this is because they were called the house of Joseph..
The correct interpretation though is that their race and their name will exist forever, and the name of Abraham, Isaac and Jacob will forever be upon them.

ויקרא בהם שמי, may their seed and the seed of their see live.

וידגו, the root is of the same category as the ones which lose the last root letter in the future tense, such as בכה, “to cry,” ויבכו, “they will cry,” or שבה, “to capture,” וישבו, “they will capture.”

המלאך הגואל אותי מכל רע יברך, the letter ה introducing the word המלאך is not a definitive article, identifying a specific angel [seeing that we had not previously heard about him; Ed] but acts as an appeal, instruction to such angel(s) who in the past on different occasions had been Yaakov’s guardian angels(s). Yaakov appeals to his own guardian angels to bless the children if their own merit does not suffice for the guardian angels assigned to them to do the job.

ויקרא בהם שמי ושם אבותי אברהם ויצחק. Although we know that Avraham and Yitzchok were both Yaakov’s fathers, he meant to make plain that he did not appeal to the god of Terach or Nachor who were similarly his “fathers” in the sense of being his ancestors. It is an axiom throughout Scripture that the righteous are never linked to those of their ancestors who were wicked, i.e. idolaters. The same is true in reverse as our sages say in Sanhedrin 52, (but not found there) קרינן לרשיעא אפילו בר צדיקא רשיעא בר רשיעא, “a wicked person, even if he is the son of a righteous person is still called a wicked person son of a wicked person.” This principle is invoked in order to save the righteous father the embarrassment of being associated with his son who has turned from the path of righteousness. When the ancestry of such a wicked person requires to be mentioned, one prefers to link him to another wicked person in his lineage. This is why Yaakov prayed for the lads that they should remain G’d fearing and prepared to serve Him. If they were to do this they would qualify to be described as offspring of Avraham and Yitzchok. This principle is known as יחד לבבי ליראה את ה', “let my heart be undivided in reverence for Your name.” (Psalms 86,11)

ויקרא בהם שמי ושם אבותי, he meant that Joseph would be called Israel on occasion, as for instance in Psalms 80,2 רועה ישראל האזינה נהג כצאן יוסף, “Give ear O shepherd of Israel who leads Joseph like a flock.” Also in Amos 6,6 we read ולא נחלו על שבר יוסף, “but they are not concerned about the ruin of Joseph;” (Joseph being a euphemism for Israel, of course) The author quotes several more verses proving the same point, i.e. that Joseph is being equated with his father Israel, i.e. is the spiritual continuation of his father Yisrael, the founder of the 12 tribes. Psalms 80,3 uses the same simile for Joseph’s sons Ephrayim and Menashe when writing לפני אפרים ובנימין ומנשה עוררה את גבורתך ולכה לישועתך לנו, “at the head of Ephrayim, Benjamin, and Menashe! Rouse Your might and come to our help!”

וידגו לרב, may the multiply like fish.

ויקרא בהם שמי ושם אבותי, “and let my name be known through them together with the name of my fathers;” He prayed that just as the 12 tribes who were physical sons of Yaakov were described as his sons, so these two grandsons should also be described as his sons.