Scania K-series is a series of bus

Bus

A bus is a road vehicle designed to carry passengers. Buses can have a capacity as high as 300 passengers. The most common type of bus is the single-decker bus, with larger loads carried by double-decker buses and articulated buses, and smaller loads carried by midibuses and minibuses; coaches are...

 with longitudinally

Longitudinal engine

In automotive engineering, a longitudinal engine is an internal combustion engine in which the crankshaft is oriented along the long axis of the vehicle, front to back....

, straight-up mounted Euro IV engine at the rear. For the 5- and 6-cylinder engines Scania is using exhaust gas recirculation

Exhaust gas recirculation

In internal combustion engines, exhaust gas recirculation is a nitrogen oxide emissions reduction technique used in petrol/gasoline and diesel engines. EGR works by recirculating a portion of an engine's exhaust gas back to the engine cylinders. In a gasoline engine, this inert exhaust...

 (EGR) system to fulfill the legal Euro IV emission standard. The K-series is available with 9-litre 5-cylinder engines with output of 230 hp (1050 Nm), 270 hp (1250 Nm) or 310 hp (1550 Nm) as well as the 12-litre 6-cylinder engines with output of 340 hp (1700 Nm), 380 hp (1900 Nm), 420 hp (2100 Nm) or 470 hp (2200 Nm).

With Euro 5 emissions becoming mandatory in Europe in 2009, Scania have released upgraded engines in order to meet these regulations.