Journaling is an integral part of engineering! It's important, especially when it comes time to apply for a patent. Being able to look back and see each part of the engineering design process is the goal and it's important that when a patent attorney questions when "x" step in your process happened, that you're able to articulate. With a journal, one can just look back and see what they did, as well as detail associated with it.
Journal every class. It shouldn't take too long and you can use the last 5 minutes of every class to journal.