登录WWW.API.ORG
1. 你会看到 ABOUT OIL AND NATURAL GAS
Industry Sectors, Gasoline, Natural Gas, Use Energy Wisely, Diesel, Oil Sands, Engine Oil, Heating Oil, Energy Tomorrow, Use Energy Safely, Energy Security, Facts on Fuel 
中间你选择Engine Oil,进入连结，
2、新的网页
Look for the Products that Carry the API Quality Marks
API's Engine Oil Quality Marks—the API Service Symbol "Donut" and Certification Mark "Starburst"—help consumers identify quality engine oils for their gasoline and diesel-powered vehicles. 、
  你就点那个look for。。。的连接，就是这个段的连接，再进到下一个页面，
3、新的页面正文里的红字连接 Licensee Directory.，你就点那个，再进连接。
4、进到新的网页 http://eolcs.api.org/  这个就是查询页面，这个可是美国石油协会的官方网站，做不了假的。直接可以查了，美国一共199家，中国一共20家左右。你可以通过
  Click here to display a list of Companies that are Engine Oil Licensees.
   Click here to display a list of Brand Names belonging to Engine Oil Licensees.
   Click here to display a list of SAE Viscosity Grades for Gasoline Engines.
   Click here to display a list of API Service Categories.
   Click here to display a list of Countries with Engine Oil Licensees.
   Click here to display a list of States and Provinces in North America with Engine Oil Licensees.
  


这点不同的地方是分企业，国家，品牌等，直接可以查。国内很多人宣传，但是很少人真正去这个网站查询。知道了这个方法，就可以查询了！