如何查api认证证书？
1、在浏览器上搜索：http://www.api.org/products-and-services/engine-oil/eolcs-licensee-directory
2、点击箭头所指位置。
3、进入以下页面，就可以录入要查询的公司英文名称或API证书编号进行查询。
所有API颁发的认证证书，皆可以在其官网上查询，具体的网站查询地址如下：
http://compositelist.api.org/search.aspx
查询方法介绍：
第一步： 登录www.API.ORG
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
中间选择Engine Oil,进入链接。
第二步：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. 、
点击look for。。。的连接，再进到下一个页面。
第三步：新的页面正文里的红字链接 Licensee Directory.，点击进入链接。
第四步：进到新的网页 http://eolcs.api.org/ 这个就是查询页面：
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 License
