The 45th World Artistic Gymnastics World Championships kicked off in Nanning, Guangxi in October. Known as a "green city", Nanning has picturesque scenery which made a good impression on Chinese and foreign guests. To green the city, Nanning has purchased a lot of green eco-friendly buses powered by Yuchai gas engines this year. Air has become fresh as vehicle exhaust decreases, creating an agreeable life for citizens and gymnasts.

Green eco-friendly vehicles are favored. On September 28, five free bus lines leading to Guangxi Sports Center were open to traffic at five stations: Landong, Chaoyang Square, Jinqiao, Wuyi and Xixiangtang. At Landong station, an array of buses for the championships powered by Yuchai gas engines went into operation. There is no difference between these buses and common buses in terms of appearance, but taking a close look, you will see "CNG" (Compressed Natural Gas) labels at the bottom left of heads. Unlike common buses with flat roofs, there are white trunks measuring tens of centimeters in the center of these buses' roofs.

The biggest benefit of these buses is energy conservation to public transport companies. According to Liao Xiuyong, manager of the Mechanical Department of Nanning Public Transport Corporation, buses' gas consumption per 100 kilometers is 25m3 to 30m3 and natural gas price is 4.95 yuan/m3, the cost can be saved by about 30 percent compared to diesel buses.

Of course, to the local government, such buses' biggest advantage is greenness and eco-friendliness compared to diesel buses. According to Dr. Zhu Zan of the Gas Power Institute of Yuchai R & D Center, natural gas engines start easily in winters with high attendance and combustion efficiency. They can effectively reduce carbon monoxide, hydrocarbon and nitric oxide emissions, almost emit no particulates and effectively alleviate haze.

Citizens have also enjoyed the benefit of green eco-friendly buses. Urban buses have thoroughly eliminated black smoke.

Apart from natural gas buses, the reporter also saw a lot of diesel buses up to the national IV emission standard in Nanning. Compared to previous national III engines, national IV buses are more eco-friendly. Last year, Nanning's public transport companies purchased over 100 double-decker buses powered by Yuchai's national IV engines once. Now these buses have all gone into operation as a new highlight of Nanning.

Technology promotes greenness and eco-friendliness. To serve the world championships, Nanning began to purchase buses powered by green eco-friendly engines in large volume this March, including 800 gas buses.

Apart from Nanning, cities including Beijing have begun to purchase gas buses in large volume. Such massive use of natural gas engines dates back to 2012 when the output of gas commercial engines increased by 96.6 percent.

Behind that is domestic internal combustion engine manufacturers' great progress in gas engine R & D. Yuchai began gas engine R & D early in the 1990s and has independently developed the ESI natural gas control system. Yuchai has also integrated the ECI second-generation (CFV) system with the ESI natural gas control system. Both technologies are typical gas control technologies which can accurately control gas supply.

Yuchai which has maturely grasped the two technical routes can well adapt to the need of the current market. The improved design of key parts such as spark plug, mixer, turbocharger, diesel, valve and seat ring has enhanced the economy and reliability of Yuchai gas engines, making Yuchai a Chinese internal combustion engine manufacturer with the largest share in the Chinese gas engine market. 80 percent of the 800 gas buses purchased by Nanning this March are powered by Yuchai gas engines. More than 1,300 of over 1,500 buses serving the world championships are powered by Yuchai's green eco-friendly engines. Yuchai's efforts and achievements in environmental protection have set a good example for the development of China's internal combustion engine industry, promoted the wide use of clean, eco-friendly and energy-conserving engines in major cities and international sports events, and added green for urban development.