All automotive firms are struggling to develop cars that are both environmentally friendly and profitable. As the field becomes more competitive, manufacturers need to find creative solutions and innovative ways to address environmental issues and provide enhanced value for customers. Eco-innovation involves the challenge of complementing classical Research and Development (R&D) processes with innovative design strategies: it cannot be limited to reducing a vehicle's environmental footprint; it must also revisit the value and performances encompassed in the offering. This change in 'design regime' calls for new managerial techniques. This paper is based on a collaborative research study with a European car manufacturer, examining the application of the Concept-Knowledge (C-K) design theory to explore how cars could be both environmental and economical. The case improves the understanding of the challenges of eco-innovation and provides an example of how the automotive industry can foster innovative capabilities in established R&D processes.