Here is a list of engineering freshman scholarships, it could range from a one-time $2,000 amount up to $15,000 per year for 4 years: https://engineering.illinois.edu/admissions/cost-and-financial-aid/freshmen-engineering-scholarships.html . Oddly, they have removed the information listing the specific amounts for each individual scholarship. From past accounts here and other information I’ve been sent, the larger 4-year awards do not appear to be based mainly upon objective academic stats, but rather mostly go to those with hooks or URM. As a female in engineering, that may qualify as an underrepresented minority so you may have a good chance at a larger award with those stats. My son had a 36 ACT and 4.0/4.7 and received a one-time $10,000 award, but he had zero hooks and was not URM. You can find other award amounts by searching this forum.
As far as I know, the engineering scholarships are funded mainly by endowment and donations to the Engineering department like the Visionary funding drive. I do not think they are related to the new AIM HIGH program in Illinois that is supposed to offer additional merit awards for low and middle income families http://osfa.illinois.edu/types-of-aid/aim-high-program . Some scholarships stack up to a maximum amount, but I don’t know whether you can receive an AIM HIGH award in addition to other campus wide awards (https://admissions.illinois.edu/Invest/scholarships-all ) or the engineering one.
Good luck, please report the outcome for future students!