Electric car startups aside, there's still plenty of room for improving the traditional cars we all grew up with. Among the many parts that go into a car, relatively few have been optimized over the years, leaving plenty of room for startups to innovate. Enerpulse chose to work on improving spark plugs, the part that ignites the fuel in internal combustion engines. A more efficient design can help to save fuel; Enerpulse says it provides about 6 percent fuel savings. The $5 million funding is the company's second, and will go toward expanding retail sales of the plugs. It was provided by Robeco, which is a subsidiary of the European-based Rabobank Group. Enerpulse has taken $10.5 million in total, with its first funding coming from Sail Venture Partners and Altira Group.