|The new bi-turbo gasoline direct injection inline-six.|
BMW is resuming the use of turbocharger technology in the design of its large-scale serial production gasoline engines.
At the Geneva auto show, the company unveiled a new in-line 6-cylinder bi-turbo engine with direct injection and fully variable camshaft control to optimize combustion. The new bi-turbo direct-injection engine produces 306 hp and 400 Nm of torque with “low fuel consumption.”
In two months, BMW will announce a first vehicle to feature this new engine generation. It will be launched on the market in the foreseeable future, according to Prof. Dr. Dr. E.h. Burkhard Göschel, Member of the Board of Management of BMW, speaking at the press conference in Geneva.
BMW first introduced turbos in Europe in 1973 with the production of the BMW 2002 Turbo, but subsequently dropped the technology in its gasoline models over concerns over fuel consumption coupled with rising fuel prices.
The new bi-turbo engine uses two small turbo chargers built with new heat-resistant material to provide an excellent response behavior.
The typical “turbo lag”—the moment right before the charger kicks in to enhance performance—has now become a thing of the past. This engine is agile, and it performs like a big naturally aspirated engine, but at much better mileage.—Dr. Göschel
The new engine also uses BMW’s High Precision Injection system. High-Precision Injection (HPI) is a lean spray-guided gasoline direct-injection technology that BMW projects will increase fuel efficiency by up to 10% in the Euro test cycle and between 5%–15% in real world driving. (Earlier post.)
A gasoline direct injection (GDI) engine sprays the fuel directly into the combustion chamber of each cylinder (as opposed to a port fuel injection (PFI) or carburetor engine) and delivers significantly increased performance and decreased fuel consumption and emissions.
First-generation GDI systems are wall-guided—the spray hits the wall, and the formation of the fuel-air cloud depends mainly on the charge movements. A spray-guided technique uses the injection procedure itself and not the charge movement to ensure that a combustible mixture is brought to the sparkplug at exactly the right time, regardless of pressure and temperature conditions.
At the Geneva show, Mercedes-Benz introduced its first production model using its own spray-guided direct injection system (earlier post.)
BMW has stated that it will implement spray-guided direct injection on all its gasoline models in the future, as well as regenerative braking and stop/start functionality.
The engine also features BMW’s BIVANOS variable camshaft system.
On a separate note, Dr. Göschel stated that company will not yet enter the US market with a diesel model without an SCR solution or equivalent. (SCR is the basis for DaimlerChrysler’s BLUETEC systems (earlier post).
If the BMW Group is to enter the American market with a diesel product, it will be with one that offers a truly sustainable solution such as the exhaust treatment by SCR technology—which is the drastic reduction of NOx content by use of urea.
Those SCR catalytic converters dramatically lower NOx content and—in cooperation with the particle filter—reduce exhaust emissions to a minimum. However, we still have quite some way to go before this trend-setting technology will be fully developed.—Dr. Göschel