How Garrett Turbochargers Contribute to the Success of BMW B57 Diesel Engines

A car is the sum of its parts. The performance of each of these parts contributes to the performance of the whole.  Brakes, electrical systems, sensors, transmissions, injectors, spark plugs -- each component has been significantly fine tuned over the past many decades to produce more power and efficiency than ever before while reducing the car's environmental impact.

An Autoevolution article this week takes a deep dive into one specific innovation that has increased the power and efficiency of BMW's B57 diesel engine while lowering emissions. The focus is on the Garrett Turbocharger. The innovation is a variable nozzle turbine. The article is titled "The Tech Behind the Garrett Turbochargers That Keep BMW B57 Diesel Engines Alive."

Here's the story.

Diesel automobile sales in the U.S. dropped off after the Dieselgate scandal of 2015. This event did not, however, disrupt the popularity of diesel cars in Europe. BMW is one of the automakers that sells plenty of diesel-powered vehicles across the pond. The important thing is to satisfy the new Euro 6d emission standards. To do this the company has done a complete makeover of its most popular diesel engine, the 3.0 B57 six-cylinder.

It is now assisted by a mild hybrid system which includes a 48-volt starter generator that provides 11 hp (8 kW) of additional power, author Vlad Radu writes. "More importantly, it optimizes the engine's load range and reduces consumption."

The improvement in efficiency is achieved by means of two-stage variable nozzle/geometry turbochargers. The end result is better fuel consumption and performance.

BMWs 3.0-liter B57 inline-six diesel engine.

Several technical innovations are involved. One has to do with seven ports integrated on the exhaust manifold, six on the exhaust and one on the EGR. The ports address exhaust pressure variations with improvements on both the high and lower pressures of the VNT. We're talking about serious fine tuning here while the engine is in action.

There's some sophisticated electronics involved as well that works together with the two VNT actuators, improving engine responsiveness. "According to Garrett, throttle response and torque deliver are smoother and more powerful when compared to single turbo or conventional two-stage turbo systems," he writes.

Relying on information from Garrett, Radu shares additional benefits. The new system setup improves boost at low rpms. And the setup also reduces the production of harmful gases even before they go through the treatment devices.

Though the two-stage NOx exhaust gas treatment system was introduced in 2012, it has gone through extensive upgrades since that time. These are areas that companies can't sit back on their haunches about. Continuous improvement is the name of the game as they perpetually push the envelope. The BMW is the epitome of sophisticated engineering, inside and out.

The redesigned B57 3.0 liter, with assistance from a 48V hybrid system, produces 340 hp and 516 lb-ft of torque, all this while becoming compliant with the EU's stringent emissions standards that have recently come into effect. 

What will they think of next?

Read the full story here: The New Tech Behind the Garret Turbchargers.

Photos on this page: BMW AG