Changsha Zhengsheng Engine Parts CO., LTD, producing piston rings with diameter longer than Ф 140 for high power diesel engines. It is the first piston rings manufacturing company in China with a history of more than 60 years. Zhengsheng is the designated component supplier for China Railway Ministry and China National Marine Cooperation. It is also the main piston rings supplier for most of the high power diesel engine factories of China. Both production and marketing of the company rank the first in China, and the quality of products is of international advanced level. Being one of the earliest factories to carry out the Total Quality Control, Zhengsheng has set down product quality regulations according to QS-9000 and ISO-9001.