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This work investigates the injection processes of an eight-hole direct-injection gasoline injector from the Engine Combustion Network (ECN) effort on gasoline sprays (Spray G). Experiments are performed at identical operating conditions by multiple institutions using standardized procedures to provide high-quality target datasets for CFD spray modeling improvement. The initial conditions set by the ECN gasoline spray community (Spray G: Ambient temperature: 573 K, ambient density: 3.5 kg/m3 (∼6 bar), fuel: iso-octane, and injection pressure: 200 bar) are examined along with additional conditions to extend the dataset covering a broader operating range. Two institutes evaluated the liquid and vapor penetration characteristics of a particular 8-hole, 80° full-angle, Spray G injector (injector #28) using Mie scattering (liquid) and schlieren (vapor).

Traditional in-tank gasoline and diesel fuel pumps require high power, 120 W or more, in fuel systems that have high flow requirements, high pressure requirements, or both. One method to reduce power consumption is to improve efficiency by using a brushless motor rather than the traditional brush style motor. The brushless motor technology also eliminates the brush to commutator interface which improves the pump's robustness to fuel and reduces flow variation. Additional benefits are provided by the controller which provides motor commutation since it enables closed loop pump speed control, pump diagnostics, and the opportunity for additional sensor interfaces to improve the fuel delivery system architecture. This paper describes the brushless motor technology, design optimization strategy for fuel pump applications, selected design, and resulting torque and efficiency performance improvements.

Advances in engine technology including Gasoline Direct injection (GDi), Dual Independent Cam Phasing (DICP), advanced valvetrain and boosting have allowed the simultaneous reductions of fuel consumption and emissions with increased engine power density. The utilization of fuels containing ethanol provides additional improvements in power density and potential for lower emissions due to the high octane rating and evaporative cooling of ethanol in the fuel. In this paper results are presented from a flexible fuel engine capable of operating with blends from E0-E85. The increased geometric compression ratio, (from 9.2 to 11.85) can be reduced to a lower effective compression ratio using advanced valvetrain operating on an Early Intake Valve Closing (EIVC) or Late Intake Valve Closing (LIVC) strategy. DICP with a high authority intake phaser is used to enable compression ratio management.

A high-frequency electrical resonance-based ignition concept is in development to replace conventional spark ignition functionality for gasoline engines employing various types of fuel injection methods. The concept provides the benefit of a continuous discharge phase and the electrical power of the discharge can also be adjusted to the needs of the combustion conditions. This concept employs an alternative method of generating high voltages, using inductors and capacitors trimmed such that the supplied energy steadily increases the output voltage. This configuration is widely known as Tesla transformer and has been engineered to operate in a modern gasoline engine combustion environment. This development allows very high break down voltages to be generated and the power into the spark itself can be influenced.

Operation of flex fuel vehicles requires operation with a range of fuel properties. The significant differences in the heat of vaporization and energy density of E0-E100 fuels and the effect on spray development need to be fully comprehended when developing engine control strategies. Limited enthalpy for fuel vaporization needs to be accounted for when developing injection strategies for cold start, homogeneous and stratified operation. Spray imaging of multi-hole gasoline injectors with fuels ranging from E0 to E100 and environmental conditions that represent engine operating points from ambient cold start to hot conditions was performed in a spray chamber. Schlieren visualization technique was used to characterize the sprays and the results were compared with Laser Mie scattering and Back-lighting technique. Open chamber experiments were utilized to provide input and validation of a CFD model.

A turbocharged 2.0L 4-cylinder direct injection spark ignition (DISI) engine designed for use with gasoline is simulated using one dimensional engine simulation. Engine design modifications - increased compression ratio, 2-step valve train with dual independent cam phasing and fuel injection timing - are considered in an effort to improve fuel economy with gasoline and take advantage of properties of ethanol fuel blends (up to E85). This paper discusses a methodology to use the simulation to quantitatively evaluate the design modification effects on fuel economy. Fuel consumption predictions from the simulation for each design are evaluated. The goal is to identify the best design with the constraints of hardware physical limitations, engine residual tolerance and knock tolerance. The result yields a specification for a 2-step valve train design and phasing requirements that can improve fuel economy for each compression ratio design.

Ethanol offers significant potential for increasing the compression ratio of SI engines resulting from its high octane number and high latent heat of vaporization. A study was conducted to determine the knock-limited compression ratio of ethanol-gasoline blends to identify the potential for improved operating efficiency. To operate an SI engine in a flex fuel vehicle requires operating strategies that allow operation on a broad range of fuels from gasoline to E85. Since gasoline or low ethanol blend operation is inherently limited by knock at high loads, strategies must be identified which allow operation on these fuels with minimal fuel economy or power density tradeoffs. A single-cylinder direct-injection spark-ignited engine with fully variable hydraulic valve actuation (HVA) is operated at WOT and other high-load conditions to determine the knock-limited compression ratio (CR) of ethanol fuel blends. The geometric CR is varied by changing pistons, producing CR from 9.2 to 12.87.

An accelerated fuel injector deposit formation test was developed to understand fuel deposit formation on fuel injectors for Gasoline Direct injection engines. As part of the test development, both a side mount and a central mount Gasoline Direct injection style 4 cylinder engines were operated in homogeneous mode. Initial attempts to form plugging deposits by running the engine continuously resulted in significant deposits forming on the exterior surface of the Gasoline Direct injection fuel injector tip; however, these deposits did not impact fuel flow. Ultimately, Gasoline Direct injection injector plugging was successfully accomplished using a test similar to the Port Fuel Injector test cycle presented in SAE 2005-01-3841 (1), “Development of a Robust Injector Design for Superior Deposit Resistance”. Test cycles included run time to reach operating temperature followed by engine soak and cool-down.