DI Boost: Application of a High Performance Gasoline Direct Injection Concept

The development of engines with high specific output and low specific fuel consumption is now more than ever becoming the main focus for powertrain product development. A combination of two primary factors is driving this demand: increased fuel cost and stricter government regulations. As worldwide fuel prices continue to increase, consumers are shifting their purchasing toward more fuel-efficient vehicles. Also fueling the demand is new federal corporate average fuel economy (CAFÉ) regulations that are in place for the timeframe from 2008 to 2011. One concept to provide both high specific output and low specific fuel consumption is the combination of turbocharging and gasoline direct fuel injection. This is an attractive concept for the North American market where sport utility vehicles, light trucks and sports cars of all sizes are in demand from consumers.

This paper describes in detail the application of direct injection (DI) and turbo charging, both the results from the engine dynamometer and implementation into a vehicle platform. This concept, referred to as DI Boost in this project, was applied using a 3.6L, dual variable cam timing (VCT), gasoline direct injection (GDI), V6 engine with twin single scroll turbochargers. The result yielded an engine with high specific output of more than 100 hp per liter with low specific fuel consumption. In the vehicle, this concept is capable of achieving super ultra low emission vehicle (SULEV) standards without elaborate after-treatment systems via high-pressure start and split injection. The DI Boost project was implemented in a Cadillac CTS-V to demonstrate the benefits in direct comparison to existing technology and to showcase this highly promising gasoline engine technology.