New Generation Multi-hole Fuel Injector for Direct-Injection SI Engines - Optimization of Spray Characteristics by Means of Adapted Injector Layout and Multiple Injection

The diesel engine is one of the solutions to slow down fossil fuel depletion due to its high efficiency. However, its high pollutant emission limits its usage in many fields. To improve its efficiency and emissions, a conventional mechanical fuel injection system (MFI) was be replaced with common rail direct injection (CRDI) system for the purpose of this study. In this way, injection parameters such as injection timing, injection pressure and multiple injection schemes can be tuned to enhance the engine performance. The rail pressure and engine speed response of the modified diesel engine was tested. It was found that by advancing the start of injection timing (SOI) timing or increasing the rail pressure, the brake torque generated can be increased. Multiple injection schemes can be implemented to reduce the peak heat release rate (HRR). Post injection was observed to increase the late combustion HRR. The maximum pressure rise rate (PRR) can be reduced by applying pilot injection. Further research was conducted on optimizing fuel injector parameters to improve the indicated mean effective pressure (IMEP) consistency and reduce injector power consumption. The consistency of IMEP was indicated by coefficient of variation (CoV) of IMEP. The injector parameters included open time, low time and duty cycle of injector signals. These parameters were optimized by carrying out response surface methodology. The optimized parameters were observed to be 230 µs for open time, 53µs for low time and 27.5% for duty cycle. The percentage of error of CoV of IMEP and injector power were found to be lower than 5% when the predicted results are compared with experimental results.

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SPRAY CHARACTERISTICS IN A DIRECT-INJECTION DIESEL ENGINE

Atomization and Sprays ◽

10.1615/atomizspr.v6.i1.50 ◽

1996 ◽

Vol 6 (1) ◽

pp. 95-109 ◽

Cited By ~ 3

Author(s):

H. C. Yang ◽

Hong Sun Ryou ◽

Y. T. Jeong ◽

Young Ki Choi

Keyword(s):

Diesel Engine ◽

Direct Injection ◽

Spray Characteristics ◽

Direct Injection Diesel Engine

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SINGLE CYLINDER ENGINE STUDIES WITH IMPINGING DIRECT INJECTION FUEL INJECTOR

10.37099/mtu.dc.etdr/558 ◽

2017 ◽

Author(s):

Ankur Gupta

Keyword(s):

Direct Injection ◽

Fuel Injector ◽

Single Cylinder ◽

Single Cylinder Engine

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Mapping the combustion modes of a dual-fuel compression ignition engine

International Journal of Engine Research ◽

10.1177/14680874211018376 ◽

2021 ◽

pp. 146808742110183

Author(s):

Jonathan Martin ◽

André Boehman

Keyword(s):

Direct Injection ◽

Fuel Combustion ◽

Dual Fuel ◽

Compression Ignition ◽

Compression Ignition Engine ◽

Combustion Modes ◽

Si Engines ◽

Dual Fuel Combustion ◽

Soot Emissions ◽

Ci Engines

Compression-ignition (CI) engines can produce higher thermal efficiency (TE) and thus lower carbon dioxide (CO2) emissions than spark-ignition (SI) engines. Unfortunately, the overall fuel economy of CI engine vehicles is limited by their emissions of nitrogen oxides (NOx) and soot, which must be mitigated with costly, resource- and energy-intensive aftertreatment. NOx and soot could also be mitigated by adding premixed gasoline to complement the conventional, non-premixed direct injection (DI) of diesel fuel in CI engines. Several such “dual-fuel” combustion modes have been introduced in recent years, but these modes are usually studied individually at discrete conditions. This paper introduces a mapping system for dual-fuel CI modes that links together several previously studied modes across a continuous two-dimensional diagram. This system includes the conventional diesel combustion (CDC) and conventional dual-fuel (CDF) modes; the well-explored advanced combustion modes of HCCI, RCCI, PCCI, and PPCI; and a previously discovered but relatively unexplored combustion mode that is herein titled “Piston-split Dual-Fuel Combustion” or PDFC. Tests show that dual-fuel CI engines can simultaneously increase TE and lower NOx and/or soot emissions at high loads through the use of Partial HCCI (PHCCI). At low loads, PHCCI is not possible, but either PDFC or RCCI can be used to further improve NOx and/or soot emissions, albeit at slightly lower TE. These results lead to a “partial dual-fuel” multi-mode strategy of PHCCI at high loads and CDC at low loads, linked together by PDFC. Drive cycle simulations show that this strategy, when tuned to balance NOx and soot reductions, can reduce engine-out CO2 emissions by about 1% while reducing NOx and soot by about 20% each with respect to CDC. This increases emissions of unburnt hydrocarbons (UHC), still in a treatable range (2.0 g/kWh) but five times as high as CDC, requiring changes in aftertreatment strategy.

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Investigation into the Relationship between Super-Knock and Misfires in an SI GDI Engine

Energies ◽

10.3390/en14082099 ◽

2021 ◽

Vol 14 (8) ◽

pp. 2099

Author(s):

Jian Gao ◽

Anren Yao ◽

Yeyi Zhang ◽

Guofan Qu ◽

Chunde Yao ◽

...

Keyword(s):

Pressure Fluctuation ◽

Direct Injection ◽

Exhaust Valve ◽

Gasoline Direct Injection ◽

Exhaust Pipe ◽

Pressure Transducers ◽

Spark Plug ◽

Si Engines ◽

Gdi Engine ◽

The Relationship

The super-knock poses new challenges for further increasing the power density of spark ignition (SI) engines. The critical factors and mechanism connecting regarding the occurrence of super-knock are still unclear. Misfire is a common phenomenon in SI engines that the mixture in cylinder is not ignited normally, which is often caused by spark plug failure. However, the effect of misfire on engine combustion has not been paid enough attention to, particularly regarding connection to super-knock. The paper presents the results of experimental investigation into the relationship between super-knock and misfires at low speed and full load conditions. In this work, a boosted gasoline direct injection (GDI) engine with an exhaust manifold integrated in the cylinder head was employed. Four piezoelectric pressure transducers were used to acquire the data of a pressure trace in cylinder. The spark plugs of four cylinders were controlled manually, of which the ignition system could be cut off as demanded. In particular, a piezoelectric pressure transducer was installed at the exhaust pipe before the turbocharger to capture the pressure traces in the exhaust pipe. The results illustrated that misfires in one cylinder would cause super-knock in the other cylinders as well as the cylinder of itself. After one cylinder misfired, the unburned mixture would burn in the exhaust pipe to produce oscillating waves. The abnormal pressure fluctuation in the exhaust pipe was strongly correlated with the occurrence of super-knock. The sharper the pressure fluctuation, the greater the intensity of knock in the power cylinder. The cylinder whose exhaust valve overlapped with the exhaust valve of the misfired cylinder was prone to super-knock.

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