A bibliometric research on next-generation vehicles using citespace

Next-generation vehicles (NGVs), which mainly refers to hybrid vehicles (HVs), plug-in hybrid vehicles (PHVs), electric vehicles (EVs), fuel-cell vehicles (FCVs), and clean diesel vehicles (CDVs), are becoming more and more popular as the potential answer to decreasing fossil fuel consumption and CO₂ emission from traffic sectors. Although the research on NGVs started in the 1990s, a systematic observation or summarization of the research on NGVs has not been performed yet. Thus, the current status, characteristics, latest trends, and issues of the research on NGVs have not been clarified yet. This research analyzed the research on NGVs recorded in the Web of Science published between 1990 to 2020 using CiteSpace, from a macro perspective. The results show that HVs and EVs are the crucial research objects in comparison with FCVs and CDVs. The research on NGVs was mainly performed by countries that own large vehicle makers or markets. However, it is noticeable that many developing countries have also started to study NGVs, which proves that NGVs have become popular globally. On the other hand, the research topics and categories of NGV study have always had a strong bias in favor of their function and technology development. Since NGVs have been sold for years in many countries already, there will be a considerable number of waste NGVs generated in the future, and so, future research should focus on recycling policies and/or recycling technology for NGVs to guarantee their sustainable development.