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Delphi is developing a new combustion technology called Gasoline Direct-injection Compression Ignition (GDCI), which has shown promise for substantially improving fuel economy. This new technology is able to reuse some of the controls common to traditional spark ignition (SI) engines; however, it also requires several new sensors and actuators, some of which are not common to traditional SI engines. Since this is new technology development, the required hardware set has continued to evolve over the course of the project. In order to support this development work, a highly capable and flexible electronic control system is necessary. Integrating all of the necessary functions into a single controller, or two, would require significant up-front controller hardware development, and would limit the adaptability of the electronic controls to the evolving requirements for GDCI.

As the industry strives to achieve improved fuel economy, stop-start systems for internal combustion engines are receiving additional focus. Studies and system proposals have been made for various electrical configurations ranging from 12 volts to 42 volts and higher [1, 2, 3]. Both cranking motor and belt alternator starter configurations have been proposed, with some concerns regarding the customer acceptance of the cranking motor solution [1] which were subsequently addressed [3]. Typically, 14 Volt Belt Alternator Starter (BAS) applications are limited to 1.6 liter gasoline (0.4 liter per cylinder) and 1.4 liter diesel (0.35 liter per cylinder) engines due to BAS torque output constraints. Some previous work extended this range to 0.7 liter per cylinder by utilizing a boosted supply voltage and auxiliary energy storage device [1].

The requirement of reduced emissions and improved fuel economy led the introduction of direct-injection (DI) spark-ignited (SI) engines. Dual-fuel injection system (direct-injection and port-fuel-injection (PFI)) was also used to improve engine performance at high load and speed. Ethanol is one of the several alternative transportation fuels considered for replacing fossil fuels such as gasoline and diesel. Ethanol offers high octane quality but with lower energy density than fossil fuels. This paper presents the combustion characteristics of a single cylinder dual-fuel injection SI engine with the following fueling cases: a) gasoline for PFI and DI, b) PFI gasoline and DI ethanol, and c) PFI ethanol and DI gasoline. For this study, the DI fueling portion varied from 0 to 100 percentage of the total fueling over different engine operational conditions while the engine air-to-fuel ratio remained at a constant level.