Well Huge Dave, congrats on the interview. As no one else has bothered to respond yet heres my tuppence. The answer is I cant help you cos Im not an engineer but Im sure someone on here can answer your query. Like most interviews for anything however, you will get asked certain stock questions about your qualifications, your interest in the job, the personal qualities you can bring to the post, etc, etc.
The best bet is to stay calm and ask a few relevant questions of the panel at the end. They will expect you to know about the company too, so the more info you can get on that the better. If you can show that you know as much as possible about the post, the company, its history and aims and objectives you will do ok.