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In previous work, Gasoline Direct Injection Compression Ignition (GDCI) has demonstrated good potential for high fuel efficiency, low NOx, and low PM over the speed-load range using RON91 gasoline. In the current work, a four-cylinder, 1.8L engine was designed and built based on extensive simulations and single-cylinder engine tests. The engine features a pent roof combustion chamber, central-mounted injector, 15:1 compression ratio, and zero swirl and squish. A new piston was developed and matched with the injection system. The fuel injection, valvetrain, and boost systems were key technology enablers. Engine dynamometer tests were conducted at idle, part-load, and full-load operating conditions. For all operating conditions, the engine was operated with partially premixed compression ignition without mode switching or diffusion controlled combustion.

The focus of this study is investigation of the influence of fuel system pressure, intake tumble charge motion and injector seat specification - namely the static flow and the plume pattern - on the GDi engine particulate emissions under the homogenous combustion operation. The paper presents the spray characteristics and the single cylinder engine combustion data for the Delphi Multec® 14 GDi multi-hole fuel injector, capable of 40 [MPa] fuel system pressure. It provides results of a study of the influence of fuel pressure increase between 5 [MPa] to 40 [MPa], for three alternative seat designs, on the combustion characteristics, specifically the particulate and gaseous emissions and the fuel consumption. In conjunction with the fuel system pressure, the effect of enhanced charge motion on the combustion characteristics is investigated.

As the emissions and fuel economy standards for internal combustion engines become ever more stringent, a variety of valvetrain control methods have been developed to improve engine performance. One of these is camshaft (CAM) phasing, which controls the angular position of the CAM relative to the crankshaft allowing changes to the timing of valve lift events. This method has demonstrated advantages including broadening the engine torque curve, increasing peak power at higher RPM, reducing hydrocarbon and NOx emissions, and improving fuel economy. In addition, external EGR systems can be eliminated because internal cylinder dilution control can be achieved by varying CAM timing. Current implementations of CAM phasing use oil-pressure-based electro-mechanical systems. While these systems are relatively low cost and have proven to be robust, they have disadvantages at low oil temperatures and pressures (such as during cranking events).

High cell density (HCD) (≥ 600 cpsi) and /or ultra thin wall (UTW) (≤ 4 mil) extruded ceramic monolith substrates are being used in many new automotive catalyst applications because they offer (1) increased geometric surface area, (2) lower thermal mass, (3) increased open frontal area and (4) higher heat and mass transfer rates. Delphi has shown in previous papers how to use the effectiveness, NTU theory, to optimize the various benefits of these HCD / UTW catalysts. A primary disadvantage of these low solid fraction substrates is their reduced structural strength, as measured by a 3-D hydrostatic (isostatic) test. The weakest of these new substrates is only 10 to 20% as strong as standard 400 × 6.5 substrates. Improved converter assembly methods with lower, more uniform forces will likely be required to successfully assemble converters with such weak substrates in production.

Fuel systems associated with Gasoline Direct Injection (GDi) engines operate at pressures significantly higher than Port Fuel Injection (PFI) engine fuel systems. Because of these higher pressures, GDi fuel systems require a high pressure fuel pump in addition to the conventional fuel tank lift pump. Such pumps deliver fuel at high pressure to the injectors multiple times per engine cycle. With this extra hardware and repetitive pressurization events, vehicles equipped with GDi fuel systems typically emit higher levels of audible noise than those equipped with PFI fuel systems. A common technique employed to cope with pump noise is to cover or encase the pump in an acoustic insulator, however this method does not address the root causes of the noise. To contend with the consumer complaint of GDi system noise, Delphi and Magneti Marelli have jointly developed a high pressure fuel pump with reduced audible output by concentrating on sources of noise generation within the pump itself.

The audible noise characteristics of direct injectors are important to OEM customers when selecting a high pressure gasoline fuel injector. The activation noise is an undesirable aspect that needs to be minimized through injector design, injector mounting, and acoustic treatments. Experimentally identifying the location and frequency of noise sources is beneficial to the improvement of injector designs. Acoustic holography is a useful tool in locating these noise sources by measuring a sound pressure field with multiple microphones and using this field to estimate the source location. For injector testing, the local boundary conditions of the noise source will affect the resultant sound field. Therefore, how the injector is mounted within the test fixture will change the resultant noise field measured. In this study, the process of qualifying an acoustic holography fixture using measurement system analysis for GDi fuel injector testing will be documented.

Innovative nozzle hole shapes for inwardly opening multi-hole gasoline direct injectors offer opportunities for improved mixture formation and particulate emissions reduction. Compared to increased fuel pressure, an alternative associated with higher system costs and increased pumping work, nozzle hole shaping simply requires changes to the injector nozzle shape and may have the potential to meet Euro 6 particulate regulations at today's 200 bar operating pressure. Using advanced laser drilling technology, injectors with non-round nozzle holes were built and tested on a single-cylinder engine with a centrally-mounted injector location. Particulate emissions were measured and coking deposits were imaged over time at several operating fuel pressures. This paper presents spray analysis and engine test results showing the potential benefits of alternative non-round nozzle holes in reducing particulate emissions and enhancing robustness to coking with various operating fuel pressures.

To meet future particulate number regulations, one path being investigated is higher fuel pressures for direct injection systems. At operating pressures of 30 MPa to 40 MPa, the fuel system components must be designed to withstand these pressures and additional power is required by the pump to pressurize the fuel to higher pressures than the nominal 15MPa to 20MPa in use today. This additional power to the pump can affect vehicle fuel economy, but may be partially offset by increases in combustion efficiency due to improved spray mixture preparation. This paper examines the impact on fuel economy from increased system fuel pressures from a combination of test results and simulations. A GDi pump and valvetrain model has been developed and correlated to existing pump torque measurements and subsequently used to predict the increase in torque and associated impact on fuel economy due to higher GDi system pressures.

Delphi Diesel Systems (DDS) - Heavy Duty Business is developing a new range of Ultra High Pressure Common Rail Fuel Injectors with the functionality to allow the combustion heat release to be heavily adapted during operation. This allows the injector performance to be simultaneously optimised across a broad range of engine conditions, removing the constraints of having to select a single rate shape type for all operating conditions. This new technology range builds on the performance of Delphi's 2700 bar Fuel Systems of F2E, F2P and F2R, whilst adding in new levels of injector control, beyond what is available in the current market. In addition to this new functionality, Delphi's new Heavy Duty Injector range also demonstrates greatly reduced leakage and improved accuracy of fuel control. This paper reviews the benefits and possibilities of this new injector technology.

Wide varieties of vehicle Engine Management Systems are designed by different Tier#1 suppliers to meet highly complex requirements with the help of electronics. Emerging technologies and features of Engine Management Systems require a number of strategies for reducing the overall timing for verification with high quality testing. Analysis and decoding of data especially for highly critical and complex such as gasoline direct injection (GDi) engine fuel delivery output, high pressure fuel pump (HPFP), spark control output and different varieties of engine position signals are time consuming. This paper introduces Virtual Engine Control Module (VECM) technology to solve the problem of decoding complex signals and high level verification. A proposed test bench setup consists of VECM, ECM, simulator and real actuator load with complete software flashed inside the ECM.

Delphi Diesel Systems' 2700bar Proven F2E Distributed Pump Common Rail System (DPCRS) has been developed to meet the requirements of Euro VI and future emissions legislation and is now in volume production in Heavy Duty Vehicles. Incorporating a number of ground breaking new technologies, the system offers numerous performance advantages. F2E provides full common rail functionality for camshaft driven Fuel Injection Equipment (FIE) engines with minimum modification. By delivering precise and accurate control of multiple injections at maximum rail pressure across all engine operating conditions, the system minimizes the demands on exhaust after treatment systems. Additionally F2E provides real time flexible capacity by employing a unique method of pump fuel metering, enabling the most efficient and accurate transient control of rail pressure combined with the low NVH and optimised efficiency.

FTP and ECE + EUDC emissions are measured from six converters having similar restriction and platinum group metals on two 1999 prototype engines/calibrations. A 2.2L four cylinder prototype vehicle is used to measure FTP emissions and an auto-driver dynamometer with a prototype 2.4L four cylinder engine is used to determine the ECE + EUDC emissions. The catalytic converters use various combinations of 400/3.5 (400cpsi/3.5mil wall), 400/4.5, 400/6.5, 600/3.5, 600/4.5, and 900/2.5 ceramic substrates in order to meet a restriction target and to maximize converter geometric surface area. Total catalyst volume of the converters varies from 1.9 to 0.82 liters. Catalyst frontal area varies from 68 cm2 to 88 cm2. Five of the six converters use two catalyst bricks. The front catalyst brick uses either a three-way Pd washcoat technology containing ceria or a non-ceria Pd washcoat technology. Pd loadings are 0.1 troy oz. of Pd.