Particulate Matter Emission Suppression Strategies in a Turbocharged Gasoline Direct-Injection Engine

2017 ◽  
Vol 139 (10) ◽  
Author(s):  
Zhang Ming ◽  
Zhong Jun ◽  
Capelli Stefano ◽  
Lubrano Luigi
Keyword(s):  
Particulate Matter ◽  
Emission Reduction ◽  
Direct Injection ◽  
Injection Pressure ◽  
Particle Emission ◽  
Gasoline Direct Injection ◽  
Injection System ◽  
Dominant Factor ◽  
Injection Timing ◽  
Wide Range

The development process of a down-sized turbocharged gasoline direct-injection (GDI) engine/vehicle was partially introduced with the focus on particulate matter (PM)/particle number (PN) emission reduction. To achieve this goal, the injection system was upgraded to obtain higher injection pressure. Two types of prototype injectors were designed and compared under critical test conditions. Combined numerical and experimental analysis was made to select the right injector in terms of particle emission. With the selected injector, the effect of injection parameters calibration (injection pressure, start of injection (SOI) timing, number of injection pulses, etc.) on PM/PN emission was illustrated. The number of fuel injection pulses, SOI timing, and injection pressure were found playing the leading role in terms of the particle emission suppression. With single-injection strategy, the injection pressure and SOI timing were found to be a dominant factor to reduce particle emission in warm-up condition and cold condition, respectively; a fine combination of injection timing and injection pressure is generally able to decrease up to 50% of PM emission in a wide range of the engine map. While with multiple injection, up to an order of magnitude PM emission reduction can be achieved. Several New European Driving Cycle (NEDC) emission cycles were arranged on a demo vehicle to evaluate the effect of the injection system upgrade and adjusted calibration. This work will provide a guide for the emission control of GDI engines/vehicles fulfilling future emission legislation.

Experimental and Numerical Analysis on the Influence of Direct Fuel Injection Into O2-Depleted Environment of a GDI-HCCI Engine

2020 ◽  
Author(s):  
Ratnak Sok ◽  
Jin Kusaka
Keyword(s):  
Fuel Injection ◽  
Direct Injection ◽  
Injection Pressure ◽  
Single Pulse ◽  
Gasoline Direct Injection ◽  
Injection Timing ◽  
Rich Mixture ◽  
Intake Stroke ◽  
Shift Reaction ◽  
Direct Fuel Injection

Abstract Injected gasoline into the O2-depleted environment in the recompression stroke can be converted into light hydrocarbons due to thermal cracking, partial oxidation, and water-gas shift reaction. These reformate species influence the combustion phenomena of gasoline direct injection homogeneous charge compression ignition (GDI-HCCI) engines. In this work, a production-based single-cylinder research engine was boosted to reach IMEPn = 0.55 MPa in which its indicated efficiency peaks at 40–41%. Experimentally, the main combustion phases are advanced under single-pulse direct fuel injection into the negative valve overlap (NVO) compared with that of the intake stroke. NVO peak in-cylinder pressures are lower than that of motoring, which emphasizes that endothermic reaction occurs during the interval. Low O2 concentration could play a role in this evaporative charge cooling effect. This phenomenon limits the oxidation reaction, and the thermal effect is not pronounced. For understanding the recompression reaction phenomena, 0D simulation with three different chemical reaction mechanisms is studied to clarify that influences of direct injection timing in NVO on combustion advancements are kinetically limited by reforming. The 0D results show the same increasing tendencies of classical reformed species of rich-mixture such as C3H6, C2H4, CH4, CO, and H2 as functions of injection timings. By combining these reformed species into the main fuel-air mixture, predicted ignition delays are shortened. The effects of the reformed species on the main combustion are confirmed by 3D-CFD calculation, and the results show that OH radical generation is advanced under NVO fuel injection compared with that of intake stroke conditions thus earlier heat release and cylinder pressure are noticeable. Also, parametric studies on injection pressure and double-pulse injections on engine combustion are performed experimentally.

An Experimental Investigation of the Effects of Common-Rail Injection System Parameters on Emissions and Performance in a High-Speed Direct-Injection Diesel Engine

1999 ◽  
Vol 123 (1) ◽  
pp. 167-174 ◽  
Author(s):  
P. J. Tennison ◽  
R. Reitz
Keyword(s):  
Diesel Engine ◽  
High Speed ◽  
Direct Injection ◽  
Injection Pressure ◽  
Injection System ◽  
Injection Timing ◽  
Pilot Injection ◽  
Common Rail Injection System ◽  
And Performance ◽  
Emissions And Performance

An investigation of the effect of injection parameters on emissions and performance in an automotive diesel engine was conducted. A high-pressure common-rail injection system was used with a dual-guided valve covered orifice nozzle tip. The engine was a four-valve single cylinder high-speed direct-injection diesel engine with a displacement of approximately 12 liter and simulated turbocharging. The engine experiments were conducted at full load and 1004 and 1757 rev/min, and the effects of injection pressure, multiple injections (single vs pilot with main), and pilot injection timing on emissions and performance were studied. Increasing the injection pressure from 600 to 800 bar reduced the smoke emissions by over 50 percent at retarded injection timings with no penalty in oxides of nitrogen NOx or brake specific fuel consumption (BSFC). Pilot injection cases exhibited slightly higher smoke levels than single injection cases but had similar NOx levels, while the single injection cases exhibited slightly better BSFC. The start-of-injection (SOI) of the pilot was varied while holding the main SOI constant and the effect on emissions was found to be small compared to changes resulting from varying the main injection timing. Interestingly, the point of autoignition of the pilot was found to occur at a nearly constant crank angle regardless of pilot injection timing (for early injection timings) indicating that the ignition delay of the pilot is a chemical delay and not a physical (mixing) one. As the pilot timing was advanced the mixture became overmixed, and an increase of over 50 percent in the unburned hydrocarbon emissions was observed at the most advanced pilot injection timing.

Computational Investigation of Combustion Phasing and Emissions for GDCI Engine Operations

2017 ◽  
Author(s):  
Mianzhi Wang ◽  
Suya Gao ◽  
Chia-fon F. Lee
Keyword(s):  
Direct Injection ◽  
Gasoline Direct Injection ◽  
Injection Timing ◽  
Compression Ignition ◽  
Engine Efficiency ◽  
Partially Premixed Combustion ◽  
Wide Range ◽  
The Moment ◽  
Fuel Evaporation ◽  
Diesel Operation

The gasoline direct-injection compression-ignition (GDCI) combustion strategy is studied in this work based on the numerically constructed ignition phase curves. Previous research has shown that for GDCI operation, the engine efficiency can reach as high as that of diesel engines yet the NOx and soot emissions can be reduced simultaneously. A comparison between GDCI and diesel operation is made by investigating two combustion regimes, partially premixed combustion (PPC) and conventional direct-injection compression-ignition (DICI). The injection timing, which determines the controllability of GDCI operation, spans over a wide range to study its effect on the combustion phasing. Fundamental processes, such as fuel evaporation, transport, and ignition are used to explain the differences between these two operating regimes. Finally, the effects of heating intake air, boosting intake air pressure, applying warm EGR are also studied. The emissions are correlated to the instantaneous parameters of the mixture at the moment of ignition, providing insights about the fundamental mechanisms of the emission reduction by adopting GDCI combustion.

scholarly journals Modelling liquid film in modern GDI engines and the impact on particulate matter emissions – Part 1

2021 ◽  
pp. 146808742110244
Author(s):  
Federico Biagiotti ◽  
Fabrizio Bonatesta ◽  
Sadjad Tajdaran ◽  
Davide Domenico Sciortino ◽  
Sunny Verma ◽  
...  
Keyword(s):  
Particulate Matter ◽  
Liquid Film ◽  
Operating Conditions ◽  
Gasoline Direct Injection ◽  
Injection System ◽  
Published Data ◽  
Injection Timing ◽  
Fuel Blend ◽  
Engine Operation ◽  
The Impact

This paper presents the details of a Computational Fluid Dynamics methodology to accurately model the process of mixture preparation in modern Gasoline Direct Injection engines, with particular emphasis on liquid film as one of the main causes of Particulate Matter formation. The proposed modelling protocol, centred on the Bai-Onera approach of droplets-wall interaction and on multi-component surrogate fuel blend models, is validated against relevant published data and then applied to a modern small-capacity GDI engine, featuring centrally-mounted spray-guided injection system. The work covers a range of part-load, stoichiometric and theoretically-homogeneous operating conditions, for which experimental engine data and engine-out Particle Number measurements were available. The results, based on the parametric variation of start of injection timing and injection pressure, demonstrate how both fuel mal-distribution and liquid film retained at spark timing, may contribute to PN emissions, whilst their relative importance vary depending on operating conditions and engine control strategy. Control of PN emissions and compliance with future, more stringent regulations remain large challenges for the engine industry. Renewed and disruptive approaches, which also consider the sustainability of the sector, appear to be essential. This work, developed using Siemens Simcenter CFD software as part of the Ford-led APC6 DYNAMO project, aims to contribute to the development of a reliable and cost-effective digital toolset, which supports engine development and diagnostics through a more fundamental assessment of engine operation and emissions formation.

Modeling Mixture Formation in a Gasoline Direct Injection Engine

2005 ◽  
Vol 73 (6) ◽  
pp. 931-939 ◽  
Author(s):  
Rossella Rotondi
Keyword(s):  
Flow Field ◽  
Fuel Injection ◽  
Direct Injection ◽  
Operating Conditions ◽  
Gasoline Direct Injection ◽  
Injection System ◽  
Fuel Spray ◽  
Computational Domain ◽  
Mixture Formation ◽  
Wide Range

Mixture formation and combustion in a gasoline direct injection (GDI) engine were studied. A swirl-type nozzle, with an inwardly opening pintle, was used to inject the fuel directly in a four stroke, four cylinder, four valves per cylinder engine. The atomization of the hollow cone fuel spray was modeled by using a hybrid approach. The most important obstacle in the development of GDI engines is that the control of the stratified-charge combustion over the entire operating range is very difficult. Since the location of the ignition source is fixed in SI engines the mixture cloud must be controlled both temporally and spatially for a wide range of operating conditions. Results show that the volume of the spark must be considered when discretizing the computational domain because it highly influences the flow field in the combustion chamber. This is because the volume occupied by the plug cannot be neglected since it is much bigger than the ones used in port fuel injection engines. The development of a successful combustion system depends on the design of the fuel injection system and the matching with the in-cylinder flow field: the stratification at part load appears to be the most crucial and critical step, and if the air motion is not well coupled with the fuel spray it would lead to an increase of unburned hydrocarbon emission and fuel consumption

An experimental study of spray mixing in a direct injection engine

2003 ◽  
Vol 4 (1) ◽  
pp. 27-45 ◽  
Author(s):  
D M Probst ◽  
J B Ghandhi
Keyword(s):  
Direct Injection ◽  
Injection Pressure ◽  
Scalar Dissipation ◽  
Injection Timing ◽  
Mixing Rate ◽  
Data Set ◽  
Direct Injection Engine ◽  
Wide Range ◽  
Planar Laser ◽  
The Mean

The effects of injection timing, injector type, injection pressure and engine flowfield on fuel spray mixing in a direct injection engine were investigated using planar laser-induced fluorescence. The fluorescence images had sufficient resolution and quality to permit, for the first time in an engine, the calculation of the scalar dissipation rate. The probability density function of the scalar dissipation scaled by the mean showed excellent agreement with turbulent jet and shear layer data for late injection conditions, indicating that the same fundamental mixing process existed in the different flows. The effect of shot noise limited such comparisons for the more homogeneous early injection conditions. A dual-metric method was developed to characterize the degree of mixedness. The two metrics employed were the spatial variation, which describes the homogeneity of the scalar population, and the mean scalar dissipation, which describes the average magnitude of local scalar gradients and represents the rate of fine-scale mixing. Using this method, it was found that the presence of a strong bulk flowfield dominated the mixing rate in the test engine, while injector characteristics showed lesser effects. The data set averaged results of the two metrics for a wide range of conditions were found to define a single, unique curve that was accurately described by a quadratic relationship. This curve defines the path that turbulent mixing follows from an initial segregated state to the fully mixed limit.

Correlation of Ignitability with Injection Timing for Direct Injection Combustion Fuelled with Compressed Natural Gas and Gasoline

2003 ◽  
Vol 217 (6) ◽  
pp. 499-506 ◽  
Author(s):  
Z Huang ◽  
S Shiga ◽  
T Ueda ◽  
H Nakamura ◽  
T Ishima ◽  
...  
Keyword(s):  
Natural Gas ◽  
Fuel Injection ◽  
Direct Injection ◽  
Injection Pressure ◽  
Gasoline Direct Injection ◽  
Injection Timing ◽  
Electrode Gap ◽  
Lean Burn ◽  
Compressed Natural Gas ◽  
Study Results

A study on the correlation of ignitability with fuel injection timing for direct injection combustion fuelled with natural gas and gasoline was carried out by using a rapid compression machine. The injection pressure of natural gas is 9 MPa and the injection pressure of gasoline is 7 MPa. The study results show that natural gas direct injection possesses higher momentum than that of gasoline, and this is beneficial to the combustion enhancement since a higher intensity of turbulence could be induced. Correlation of ignitability with injection timing shows better behaviour in natural gas direct injection, and this correlation is insensitive to injection modes in the case of natural gas. Thus, natural gas direct injection would have better engine applicability under cold-start conditions. The lean burn limits of natural gas and gasoline direct injection can extend to extremely low equivalence ratio when the ignitable stratified mixture exists around the spark electrode gap by optimizing the injection timing.

The Research of Lean Combustion Characteristic of Compound Injection System of Direct Injection Engine

2014 ◽  
Vol 532 ◽  
pp. 362-366 ◽  
Author(s):  
Jiang Feng Mou ◽  
Rui Qing Chen ◽  
Yi Wei Lu
Keyword(s):  
Gasoline Engine ◽  
Direct Injection ◽  
Injection System ◽  
Intake Manifold ◽  
Combustion Characteristic ◽  
Injection Timing ◽  
Mixed Gas ◽  
Lean Burn ◽  
Direct Injection Engine ◽  
Lean Combustion

This paper studies the lean burn limit characteristic of the compound injection system of the direct-injection gasoline engine. The low pressure nozzle on the intake manifold can achieve quality homogeneous lean mixture, and the direct injection in the cylinder can realized the dense mixture gas near the spark plug. By adjusting the two injection timing and injection quantity, and a strong intake tumble flow with special shaped combustion chamber, it can produces the reverse tumble to form different hierarchical levels of mixed gas in the cylinder. Experimental results show: the compound combustion system to the original direct-injection engine lean burn limit raise 1.8-2.5 AFR unit.

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