陶瓷气门 陶瓷气门比钢轻60％,旋转质量小50％。在试验中,这些气门已使燃料经济性提高3％～5％,气门头的应力减小,并且还可使用更轻更小的气门弹簧。然而,陶瓷气门的成本为普通气门的3倍,这几乎与充钠气门相同。奔驰、宝马和大众均在试验充钠气门,目前这些公司用燃料来冷却充钠气门,而更加严格的排放标准不久将结束这种做法。因此,陶瓷气门会满足它们的需求。 Ceramic valves Ceramic valves are 60% lighter than steel and 50% less rotating. In tests, these valves have improved fuel economy by 3% to 5%, reduced stress on the valve head, and the use of lighter and smaller valve springs. However, the cost of a ceramic valve is three times that of a normal valve, which is almost the same as filling a sodium valve. Mercedes-Benz, BMW and Volkswagen are all testing sodium-filled valves, and these companies currently use fuel to cool their chargers and the more stringent emission standards will soon come to an end. Therefore, ceramic valves will meet their needs.