Traditional engines versus all kinds of alternatives: performance and emissions

This article mainly focuses on the comparison between traditional engines and alternatives in multiple data and points of views. With the development of technology and the energy crisis, new automobile technologies have been invented. Our research on alternatives covers Hybrid electric (plug-in) Vehicle (HEVs), Electric Vehicle and Fuel cells. We analyze them one by one theoretically based on the data from sources. Each technology has its own characteristics and unique points. In our perspective, hybrid electric vehicles will be the transitional and main technology in recent years. Electric vehicles will be the most popular type of vehicle in the future. Fuel cell vehicles have their own benefits and drawbacks and it will not be popularized until the drawbacks are nearly eliminated.