The competitiveness within the automotive sector increases constantly. Research institutes, universities and manufacturers are commonly trying to discover the new trends and to develop novel technologies. Nevertheless, it is important to understand if a certain technology is worth researching. In order to do that, a state of the art survey is necessary which is usually divided in two main groups: Literature Information and Market Analysis. The literature information regards papers, congress proceedings, books, among other types of formal publication. The market analysis is responsible to gather information within the manufacturers press releases, websites and events, for example. Even though, depending on the technology, those two topics are not enough to reveal the importance of a given technology. Therefore, it is necessary to search the patents database, where it is possible to find the development status of a device. However, a patent survey it is not trivial and some methodology is needed. This papers aims on proposing a proper methodology for patent survey focused on automotive mechanisms such as gear trains, suspensions, steering and engines. The methodology it is explained step by step and a brief overview about patents is given. At the end a case study regarding the Variable Compression Ratio engines is given. This proper methodology for patent survey allowed the researchers to propose an enhanced classification for the VCR topic, to help defining design requirements and to understand the potential for innovation within the desired topic.