Medium-duty engine has always been Yuchai's traditional advantage. It has outstanding performance in all power fields, especially in the bus market. In 2003, Yuchai embarked on the road of "expanding heavy-duty operations and supplementing the light-duty sector", beginning to march towards the heavy-duty vehicle power market engine manufacturers vied for. As Yuchai's key product on its road of "heavy expansion", new-generation heavy-duty engine YC6MK has seen its sales grow year by year since its launch, gaining wide praise from vehicle plants and terminal customers.

Strong power, high comfort

Yuchai YC6MK engine is a fully-improved and more technically mature new-generation four-valve heavy-duty engine developed and designed in association with AVL according to characteristics of segments like 12m+ coaches, tour buses and urban BRT buses. It is powerful, reliable, efficient, fuel-conserving, low-noise and environmental-friendly. The national IV model uses Bosch high-pressure common-rail +SCR technology, with a power range of 320hp-420hp. 1,900rpm and 2,100rpm versions of YC6MK have been launched for choice according to market demands to pioneer the new tide of bus power upgrading.

YC6MK's displacement, maximum power and output torque have increased to 10.3L (from YC6M's 9.8L), 420hp and 800NM respectively. Besides, the high-efficiency supercharger makes fuel consumption lower, acceleration faster and power stronger. The patented four valve technology makes air intake fuller and power stronger; the super strong low-speed torque boosts engine acceleration and performance.

Besides, the four valve technology makes air intake smoother, effectively reduces air intake efficiency and enhances riding comfort. The fully optimized piston line and cylinder clearance make the sound of piston click lower, thus effectively controlling noise production. Besides, the multi-layer clad steel plate noise-reducing sump effectively reduces overall noise and vibration. The above-mentioned optimization reduces YC6MK's overall noise by 2dB to 4dB compared to similar products.

Lower fuel consumption, lower emission

The overall fuel consumption of vehicles largely depends on engine fuel consumption. Amid mounting oil prices and toll charges, engine fuel economy has drawn attention from a growing number of consumers.

YC6MK's mature patented four valve technology boosts the circulation area and efficiency of engine intake and exhaust and makes combustion fuller; enormously reduces mechanical loss by over 15 percent, increases effective output power and reduces fuel consumption. The intelligent electronically-controlled injection system precisely controls injection timing and injection quantity to boost fuel economy. Besides, with a multifunctional economy switch, YC6MK can operate according to different power curves in different conditions to enhance fuel conservation.

While enhancing fuel economy, YC6MK has a higher emission level. The patented four valve technology boosts combustion efficiency and substantially reduces harmful gas emission. Four valves facilitate combustion organization and controls emission from combustion. The low-inertia and small-aperture mid fuel injector makes the matching of injection quantity and the combustion chamber more rational, and combustion fuller.

YC6MK fully meets the requirements of the national IV emission standards so that customers can easily deal with the emission standard switch at present.

High reliability, wide adaption

Higher reliability is another advantage of YC6MK. Upon joint improvement by Yuchai and AVL, YC6MK can work under a maximum explosion pressure of 180b, is fully geared to European high-end heavy-duty engines and is more reliable. Besides, the integrated cylinder cover makes the air channel more consistent, outstanding and reliable. Also, the wet cylinder liner is more durable, boosting its useful life; the standard intelligent filter makes engine combustion cleaner and the injection system more durable. You need only to replace the element rather than the shell during maintenance to save worry and money.

In terms of safety, to enhance passive safety, YC6MK uses an improved variable valve exhaust brake (VVEB) to increase the braking force by 55 percent, thus preventing problems like power attenuation when vehicles run down long slopes.

YC6MK's advantages in power, economy and reliability have decided its wider adaptation. According to sources, as a key product with which Yuchai marches towards the heavy-duty engine power market, YC6MK has not only performed strongly in Yuchai's traditional advantaged bus market, but also achieved brilliant results in the special vehicle market and the heavy-duty truck market.

(Li Xiaofei/cvnews.com.cn)