From January to November this year, the total sales of Yuchai 6L and 6M heavy truck engines doubled year-on-year, with YC6L sales increasing by more than 80% year-on-year from January to November. The sales volume is expected to double in the whole year; the YC6M engine sales from January to November are year-on-year The growth rate has exceeded 100%. In November, the four-valve structure of the two engines had the highest sales volume, accounting for about 80% of sales. Lightweight design is a new topic in the development of China's auto industry. Selecting a lightweight design engine is an effective solution to reduce the weight of the entire vehicle. YC6L is a mature lightweight design four-valve engine . The engine is equipped with light weight highway heavy trucks with a total weight of not more than 55 tons. It has obvious advantages such as light weight, low fuel consumption and is welcomed by users. YC6M project dump trucks, mining dump trucks and cement mixer trucks have been further improved in sales this year. The low-speed, high-torque, low-speed and low fuel consumption advantages of highway engines have also been favored by some expert highway heavy truck users. This engine adapts to the highway heavy truck with small speed ratio rear axle, and can achieve high-grade, high-speed climbing, which can meet the heavy-card household's pursuit of high-speed and high-speed highway heavy trucks. The continuous increase in the sales volume of heavy-duty truck engines, especially four-valve products, also means that China's heavy-duty truck users gradually shift to four-valve products, and the two-valve heavy truck engines will gradually fade out of the market.