I have no idea about the name. It was about a man who went back in time to the middle ages from the future. He stuck there. He became a knight because of his understanding of modern science. And he spent time trying to build modern conveniences. The other thing that I remember is that his decedents from the future were able to help him by sending back a genetically enhanced horse.
The other thing that my teenage brain remembers is that he had many sexual escapades with the local women, and if they got pregnant, they would get married off, but there was one woman who was special and he tried not to get her pregnant.