Your work environment will be full of research and experimentation. You will be required to report to car factories in order to observe the testing and manufacturing stage. You will test out your ideas and record them properly. You will spend a lot of time on sketchbooks as well as drawing software. The work hours could be a little erratic, depending on the project you are working on. It could be anywhere between 40-55 hours per week with the occasional overtime.
If you choose to teach for a living, your work life will be far more relaxed. You will guide upcoming engineers and help build their skills. The hours will be comparatively easier and will depend on the university you join as a professor.
You could also opt for a mix of the above jobs and become an in-house researcher. This way you are associated with a particular automobile brand. However, in this case you will work only on theories and research data. The testing will be carried out by others.