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Technical Paper

The Effects of GDi Fuel Pressure on Fuel Economy

2014-04-01
2014-01-1438
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.
Technical Paper

Beyond Euro VI - Development of A Next Generation Fuel Injector for Commercial Vehicles

2014-04-01
2014-01-1435
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.
Technical Paper

GDi Nozzle Parameter Studies Using LES and Spray Imaging Methods

2014-04-01
2014-01-1434
Development of in-cylinder spray targeting, plume penetration and atomization of the gasoline direct-injection (GDi) multi-hole injector is a critical component of combustion developments, especially in the context of the engine downsizing and turbo-charging trend that has been adopted in order to achieve the European target CO2, US CAFE, and concomitant stringent emissions standards. Significant R&D efforts are directed towards the optimization of injector nozzle designs in order to improve spray characteristics. Development of accurate predictive models is desired to understand the impact of nozzle design parameters as well as the underlying physical fluid dynamic mechanisms resulting in the injector spray characteristics. This publication reports Large Eddy Simulation (LES) analyses of GDi single-hole skew-angled nozzles, with β=30° skew (bend) angle and different nozzle geometries.
Technical Paper

F2E - Ultra High Pressure Distributed Pump Common Rail System

2014-04-01
2014-01-1440
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.
Journal Article

Development of a Gasoline Direct Injection Compression Ignition (GDCI) Engine

2014-04-01
2014-01-1300
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.
Journal Article

Fuel System Pressure Increase for Enhanced Performance of GDi Multi-Hole Injection Systems

2014-04-01
2014-01-1209
The progressive trend towards the GDi engine downsizing, the focus on better fuel efficiency and performance, and the regulatory requirements with respect to the combustion emissions have brought the focus of attention on strategies for improvement of in-cylinder mixture preparation and identification and elimination of the sources of combustion emissions, in particular the in-cylinder particulate formation. This paper discusses the fuel system components, injector dynamics, spray characteristics and the single cylinder engine combustion investigation of a 40 [MPa] capable conventional GDi inwardly-opening multi-hole fuel injection system. It provides results of a study of the influence of fuel system pressure increase between 5 [MPa] to 40 [MPa], in conjunction with the injector static flow and spray pattern, on the combustion characteristics, specifically the particulate and gaseous emissions and the fuel economy.
Technical Paper

Individual Cylinder Fuel Control for a Turbocharged Engine

2014-04-01
2014-01-1167
This paper discusses on-engine results achieved in applying an algorithm-based Individual Cylinder Fuel Control (ICFC) to turbocharged four-cylinder engines. ICFC is a software algorithm which permits the detection and closed-loop correction of air/fuel imbalances on a cylinder-by-cylinder basis, which is not possible with typical bank-wide closed loop fuel control systems. Cylinder-to-cylinder air/fuel imbalances can be the result of a number of combined sources. The potential sources include fuel injector variation (both new and aged) as well as maldistribution of fresh air airflow, evaporative emissions purge flow, or exhaust gas recirculation flow. The ICFC algorithm requires no additional hardware beyond the typical sensor set already present on modern automotive spark-ignition engines, including oxygen sensor(s) and engine controller.
Technical Paper

Development of a Low-Noise High Pressure Fuel Pump for GDi Engine Applications

2013-04-08
2013-01-0253
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.
Technical Paper

Delphi's Heated Injector Technology: The Efficient Solution for Fast Ethanol Cold Starts and Reduced Emissions

2012-04-16
2012-01-0418
Most current flex-fuel vehicles are capable of operating on gasoline/ethanol blends from E0 to E85. The presence of gasoline in the fuel enables cold startability because some of its more volatile components can still vaporize at cold temperatures and produce an ignitable mixture. However when E100 is used, other means are required for cold starting because of ethanol's relatively low vapor pressure at low temperatures. A common technique is to employ an auxiliary gasoline fuel system for use only when temperatures are too low for the vehicle to start on E100 alone. But the added cost, complexity and maintenance of such systems have driven the search for a simpler approach. One such technique is to heat the fuel prior to injection. Fuel systems currently exist where heating occurs within the main conduit of the fuel rail. Another method is to heat the fuel within each fuel injector.
Technical Paper

Ethanol Flex Fuel system with Delphi Heated injector application

2014-04-01
2014-01-1369
After the second worldwide oil crisis, Brazil put in place by 1975 a strategic plan to stimulate the usage of ethanol (from sugar cane), to be mixed to the gasoline or to be sold as 100% ethanol fuel (known as E100). To enable an engine to operate with both gasoline and ethanol (and their mixtures), by 2003 the “Flex Fuel” technology was implemented. By 2012 calendar year, from a total of about 3.8 million vehicles sold in the Brazilian market, 91% offered the “Flex Fuel” technology, and great majority used a gasoline sub-tank to assist on cold starts (typically below 15°C, where more than 85% of ethanol is present in fuel tank). The gasoline sub-tank system suffers from issues such as gasoline deterioration, crash-worthiness and user inconvenience such as bad drivability during engine warm up phase. This paper presents fuel injector technologies capable of rapidly electrically heating the ethanol fuel for the Brazilian transportation market.
Journal Article

Fuel Pressure and Charge Motion Effects on GDi Engine Particulate Emissions

2015-04-14
2015-01-0746
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.
Technical Paper

Concept of Virtual Engine Control Module for High Quality and Time Efficient Verification and Testing of Powertrain Engine Control Module

2015-04-14
2015-01-0170
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.
Technical Paper

Design Guidelines for Automotive Fuel Level Sensors

2002-03-04
2002-01-1074
Most current automotive and light truck fuel level sensors are essentially rotary potentiometers that have been designed to survive the chemically harsh environments found in the fuel tank. This paper will chronicle the design improvements made from the early wire wound versions to today's more robust thick film ink systems. The paper will highlight potential failure modes and discuss techniques to reduce noise and increase wear life. Data will be provided regarding changes in the circuit layout, ink compositions, and contact materials. Special consideration will be given to the adverse effects associated with the reactive sulfur prevalent in today's fuels.
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