Garrett’s Most Advanced Two-Stage VNT Tech Boosts New, High-End 3.0-liter Diesel Engine
2nd Gen Modular BMW I6 Engine Brings Host of New Tech on High Performance Diesels; 48V Starter-Generator Shows Potential of Hybrid Turbodiesels
Garrett’s two-stage VNT turbochargers, or “VNT-VNT” (variable nozzle/geometry turbos at both the high and low-pressure stages) are boosting BMW Group’s more efficient, cleaner and powerful new diesel engine.
Garrett’s expertise and technologies enable the engine to achieve fuel consumption and performance objectives by introducing several technical innovations to the well-established two-stage turbocharger system, the net result of which is a 3.0-liter I6 engine producing 250 kW (340 hp) and 700 Nm (516 lb./ft.) of torque, all while meeting stringent EU6d emissions standards.
“Our advanced diesel technologies continue to meet, and, in many cases, exceed both regulatory emissions standards and requirements by our customers,” said Pierre Barthelet, Garrett Senior Vice President, Marketing and Product Management. “Our global team of innovators and inventors support the broadest range of vehicle and engine types. Helping to enable cleaner and more efficient diesel technologies continues to be a priority for Garrett and we’re thrilled with the results.”
New Integrated Manifold
One of the enhancements involve using seven ports on the integrated exhaust manifold – six for the exhaust and one for exhaust gas recirculation (EGR) –that combined help enhance the control of intake and exhaust pressure differentials, which in turn help control turbo boost pressures of both the high pressure and lower pressure VNT turbos.
New Bypass Valve
Also, the addition of a novel electronically actuated turbine bypass valve in in conjunction with to the two VNT actuators improves engine responsiveness and controllability, especially when the engine transitions from single-stage to two-stage operation. Compared to single turbo or conventional two-stage turbos, throttle response and torque delivery are made smoother and more powerful at the same time, in part, through the addition of the new bypass valve.
VNT on High Pressure Turbine
With the addition of Garrett’s latest VNT technology on the high-pressure side, the customer is enabled to better tailor and control turbo boost at low-engine rpm and also help transition the second low-pressure stage at now higher engine speeds (2,250 rpm) which helps the second stage focus on higher-efficiency operating ranges.
The water-cooled Garrett compressor, which is also used by the BMW group, enables higher rate EGR capability, which in turns reduces NOx production before the exhaust passes through the aftertreatment devices (i.e. lower engine out emissions). This allows it to achieve extraordinary power and torque outputs, while still meeting stringent European Union 6d emissions standards.
3-liter Turbocharged Diesel Making an Impressive 340 horsepower and 516 Pound-Feet of Torque
The net result of all of these innovations, in combination with the small 48V starter-generator system, is a remarkable 340 hp and 516 pound-feet (700 Nm) of torque. Installed in BMW’s 7-series sedan and X5 XDrive 40d, both vehicles are capable of sub-six second 0-60 mph (0-100 km/h) acceleration while achieving very good highway and urban fuel efficiency ratings.
To read more about these remarkable vehicles and engines, please see BMW’s press release.