Knowledge management has recently become the focus of public attention in business and engineering. Because knowledge acquisition is situated in the upstream of knowledge management, capturing knowledge is an important step for enterprises to achieve successful knowledge management. We focus on how engineers solve their design problems under given design contexts and propose a novel model and methods to capture knowledge from engineering design processes. Our goal is to acquire know-how knowledge without disrupting the normal design process. A three-layer design process model is introduced to represent generic design processes, and a grammar and extended dynamic programming (GEDP) method is developed based on the process model. GEDP adopts the grammar approach and EDP to automatically identify meaningful clusters, called operations, from primitive design events. Our approach is evaluated through a case study of designing a double-reduction gear system.