X12 CUMMINS COACH ENGINE EURO VI PHASE-D
At Busworld in Brussels Cummins introduced the new X12 engine with up to 480 hp (360 kW) output for powering full size touring and intercity coaches. This new X12 is certified to the stringent Euro VI Phase-D stage and has a new architecture eliminating the need for exhaust gas recirculation (EGR).
Other advanced design features include techniques to minimize friction losses and a weight-saving sculptured engine block. The result is a fuel-saving 11.8-litre engine weighing 920 kg, but with the heavy-duty strength required for 12-to-15 metre high deck coaches. The high flow air-handling system of the X12 gives a faster pedal response to enhance driveability at full vehicle loading, together with a rapid gradient climbing ability. A high peak torque of up to 2300 Nm is delivered across a wide engine speed range. Equally powerful is the engine braking with 370 hp (275 kW) delivered at 2100 rpm.
Substantial weight savings are achieved by using high-strength composite materials for the oil pan and valve cover. The XPI fuel system on the X12 is derived from the more powerful X15 engine, with Cummins injection technology to increasing vehicle demands, while minimizing fuel consumption.
The EGR-free X12 lowers heat rejection by around 40 percent compared with that of similar engines using cooled EGR while meeting Euro VI Phase-D, which focus on tighter control limits for Nitrogen Oxides (NOx) emissions during lower speed operations, as well as under cold engine start conditions. Duty cycle-based testing using high precision Portable Emissions Measurement systems (PEMs) installed on Cummins-powered vehicles has indicated a 25 percent reduction in NOx emissions, compared to the Phase-A engines when Euro VI was introduced in 2015, Cummins states.
X12 architectural simplicity is further reflected in the use of a Cummins high-efficiency wastegate turbocharger, as the base engine already provides high power density without requiring a more complex turbocharging boost system.
According to Brian Wilson, Cummins Executive Director – Global Bus Business, this new X12 engine sets a new benchmark in its class. “With the engine now in full production we are delighted to see the first King Long coaches being equipped with the X12. At Busworld King Long showed the C13HD High Deck and U13 Intercity coach.”