Cummins Details New Two-Stage Turbo for Nissan Titan Diesel
Earlier this month, Cummins revealed specifics behind the turbocharger that will show up in the next-generation diesel-powered Nissan Titan. The Cummins Turbo Technologies-supplied system is called the Holset M2 and features a number of innovations that will help the Cummins Titan throw down some good numbers from its 5.0L diesel V-8.
The two-stage turbo system is designed to reduce low-speed turbo lag while still providing great high-end power. However, unlike other series sequential turbocharger systems, the twin-turbine Holset unit uses just one rotary valve that incorporates a turbo bypass, a wastegate, exhaust-gas temperature regulation, and engine braking, all from a single device.
To be totally honest, you’d have to be much smarter than we are to understand all of the specifics, but it boils down like this: At low engine speeds, the rotary valve directs most of the spent exhaust gas to the system’s smaller turbine, which spools quickly and reduces turbo lag. As the engine picks up speed, the rotary valve feeds more exhaust into the larger turbine before shutting off the small turbine at high engine speeds. The idea is to ensure smooth, linear power delivery that doesn’t sacrifice either low or high-rpm torque.
In addition to working like a bypass, the valve can increase backpressure if needed to elevate exhaust temperature, which is useful for diesel-exhaust aftertreatment, and in some applications, the valve will be able to act as an engine brake. While the valve technology sounds somewhat complicated, we have no doubt that the system will be thoroughly vetted for reliability and durability, something we’ve come to expect of all Cummins products.
The compact, multi-purpose nature of the valve (and the series sequential turbo system in general) means that it will be versatile for many different applications, including engine bays where space is placed at a premium. This makes a twin-turbo system feasible on such a small platform as a 1/2-ton pickup.
It does nothing but whet our appetite for the diesel Titan all the more, which Nissan promises is #CumminsSoon.
Source: Cummins Turbo Technologies