Core Viewpoint - The article discusses the differences between various grades of gasoline (92, 95, and 98) and diesel fuel in China, focusing on octane ratings and their impact on engine performance and fuel efficiency [1][3][5]. Group 1: Gasoline Standards and Composition - In China, gasoline is categorized into 89, 92, 95, and 98 grades, with higher numbers indicating better anti-knock properties [3]. - The octane number (RON) is a measure of gasoline's resistance to knocking, with higher values indicating better performance [3][5]. - Gasoline is primarily used in spark-ignition engines, and its density typically ranges from 0.720 to 0.775 g/cm³ [1]. Group 2: Impact of Octane Rating on Engine Performance - Higher octane ratings allow for higher compression ratios in engines, which can enhance power output and fuel economy [5][10]. - Low octane fuel can lead to knocking, which negatively affects engine efficiency and can cause damage to engine components [5][10]. - The Research Octane Number (RON) is determined using a specific testing method under controlled conditions, while the Motor Octane Number (MON) uses different testing conditions [5][7]. Group 3: Fuel Efficiency and Consumer Perception - Many consumers believe that using higher octane fuel (like 95) leads to better fuel efficiency, but studies show that the difference in energy content between 92 and 95 octane is minimal, around 1% [8][10]. - The perception of improved performance with higher octane fuel may be psychological, as the density difference between 92 and 95 octane is negligible [8]. - The actual fuel efficiency benefits of using higher octane fuel depend on the specific vehicle and its operating conditions, and in many cases, the difference may be insignificant [10].