Super Ignition Spark Plug with Wear Resistive Electrode

The electric and thermal properties of the resistor material in an automotive spark plug should be stable during its service lifetime. Containing many elements and many phases, this material has a very complex microstructure. Elemental mapping with an electron microprobe can reveal the distribution of all relevant elements throughout the sample. In this work, it is demonstrated that the charge-up effect, which would distort an electron image and, therefore, is normally to be avoided in an electron imaging work, could be used to advantage to reveal conductive and resistive zones in a sample. Its combination with elemental mapping can provide valuable insight into the underlying conductivity mechanism of the resistor.This work was performed in a CAMECA SX-50 microprobe. The spark plug used in the present report was a commercial product taken from the shelf. It was sectioned to expose the cross section of the resistor. The resistor was known not to contain the precious metal Au as checked on the carbon coated sample. The sample was then stripped of carbon coating and re-coated with Au.

Download Full-text

Optical Investigation of a Partial Fuel Stratification Strategy to Stabilize Overall Lean Operation of a DISI Engine Fueled with Gasoline and E30

Energies ◽

10.3390/en14020396 ◽

2021 ◽

Vol 14 (2) ◽

pp. 396

Author(s):

Cinzia Tornatore ◽

Magnus Sjöberg

Keyword(s):

Volume Fraction ◽

Direct Injection ◽

Combustion Process ◽

Pilot Injection ◽

Optical Investigation ◽

Flame Kernel ◽

Lean Combustion ◽

Fuel Stratification ◽

Spark Plug ◽

Initial Flame

This paper offers new insights into a partial fuel stratification (PFS) combustion strategy that has proven to be effective at stabilizing overall lean combustion in direct injection spark ignition engines. To this aim, high spatial and temporal resolution optical diagnostics were applied in an optically accessible engine working in PFS mode for two fuels and two different durations of pilot injection at the time of spark: 210 µs and 330 µs for E30 (gasoline blended with ethanol by 30% volume fraction) and gasoline, respectively. In both conditions, early injections during the intake stroke were used to generate a well-mixed lean background. The results were compared to rich, stoichiometric and lean well-mixed combustion with different spark timings. In the PFS combustion process, it was possible to detect a non-spherical and highly wrinkled blue flame, coupled with yellow diffusive flames due to the combustion of rich zones near the spark plug. The initial flame spread for both PFS cases was faster compared to any of the well-mixed cases (lean, stoichiometric and rich), suggesting that the flame propagation for PFS is enhanced by both enrichment and enhanced local turbulence caused by the pilot injection. Different spray evolutions for the two pilot injection durations were found to strongly influence the flame kernel inception and propagation. PFS with pilot durations of 210 µs and 330 µs showed some differences in terms of shapes of the flame front and in terms of extension of diffusive flames. Yet, both cases were highly repeatable.

Download Full-text

Novel resistive electrode structure for liquid crystal modal lens shifting

10.1117/12.909233 ◽

2012 ◽

Cited By ~ 3

Author(s):

Nicolas Fraval ◽

Frédéric Berier ◽

Olivier Castany

Keyword(s):

Liquid Crystal ◽

Electrode Structure ◽

Resistive Electrode

Download Full-text

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.

Download Full-text

Applicability of Ionization Current Sensing Technique with Plasma Jet Ignition Using Pre-Chamber Spark Plug in a Heavy Duty Natural Gas Engine

10.4271/2012-01-1632 ◽

2012 ◽

Cited By ~ 4

Author(s):

Ashish Shah ◽

Per Tunestal ◽

Bengt Johansson

Keyword(s):

Natural Gas ◽

Plasma Jet ◽

Heavy Duty ◽

Current Sensing ◽

Gas Engine ◽

Natural Gas Engine ◽

Ionization Current ◽

Spark Plug

Download Full-text

Development and Fabrication of Silicon Nitride Components for Ceramic Gas Turbine

Volume 4: Manufacturing Materials and Metallurgy; Ceramics; Structures and Dynamics; Controls, Diagnostics and Instrumentation; Education; IGTI Scholar Award ◽

10.1115/97-gt-067 ◽

1997 ◽

Author(s):

Keisuke Makino ◽

Ken-Ichi Mizuno ◽

Toru Shimamori

Keyword(s):

High Temperature ◽

Silicon Nitride ◽

Gas Turbine ◽

Gas Turbines ◽

Turbine Blades ◽

High Strength ◽

Inlet Temperature ◽

Turbine Inlet Temperature ◽

Spark Plug ◽

Power Turbine

NGK Spark Plug Co., Ltd. has been developing various silicon nitride materials, and the technology for fabricating components for ceramic gas turbines (CGT) using theses materials. We are supplying silicon nitride material components for the project to develop 300 kW class CGT for co-generation in Japan. EC-152 was developed for components that require high strength at high temperature, such as turbine blades and turbine nozzles. In order to adapt the increasing of the turbine inlet temperature (TIT) up to 1,350 °C in accordance with the project goals, we developed two silicon nitride materials with further unproved properties: ST-1 and ST-2. ST-1 has a higher strength than EC-152 and is suitable for first stage turbine blades and power turbine blades. ST-2 has higher oxidation resistance than EC-152 and is suitable for power turbine nozzles. In this paper, we report on the properties of these materials, and present the results of evaluations of these materials when they are actually used for CGT components such as first stage turbine blades and power turbine nozzles.

Download Full-text

Study of High Load Operation Limit Expansion for Gasoline Compression Ignition Engines

Journal of Engineering for Gas Turbines and Power ◽

10.1115/1.1805548 ◽

2006 ◽

Vol 128 (2) ◽

pp. 377-387 ◽

Cited By ~ 24

Author(s):

Koudai Yoshizawa ◽

Atsushi Teraji ◽

Hiroshi Miyakubo ◽

Koichi Yamaguchi ◽

Tomonori Urushihara

Keyword(s):

Fuel Injection ◽

Control Method ◽

Combustion Process ◽

High Load ◽

Compression Ignition ◽

Ignition Timing ◽

Timing Control ◽

Load Range ◽

Compression Ignition Engines ◽

Spark Plug

In this research, combustion characteristics of gasoline compression ignition engines have been analyzed numerically and experimentally with the aim of expanding the high load operation limit. The mechanism limiting high load operation under homogeneous charge compression ignition (HCCI) combustion was clarified. It was confirmed that retarding the combustion timing from top dead center (TDC) is an effective way to prevent knocking. However, with retarded combustion, combustion timing is substantially influenced by cycle-to-cycle variation of in-cylinder conditions. Therefore, an ignition timing control method is required to achieve stable retarded combustion. Using numerical analysis, it was found that ignition timing control could be achieved by creating a fuel-rich zone at the center of the cylinder. The fuel-rich zone works as an ignition source to ignite the surrounding fuel-lean zone. In this way, combustion consists of two separate auto-ignitions and is thus called two-step combustion. In the simulation, the high load operation limit was expanded using two-step combustion. An engine system identical to a direct-injection gasoline (DIG) engine was then used to validate two-step combustion experimentally. An air-fuel distribution was created by splitting fuel injection into first and second injections. The spark plug was used to ignite the first combustion. This combustion process might better be called spark-ignited compression ignition combustion (SI-CI combustion). Using the spark plug, stable two-step combustion was achieved, thereby validating a means of expanding the operation limit of gasoline compression ignition engines toward a higher load range.

Download Full-text

Effects of H2 Addition to CNG Blends on Cycle-to-Cycle and Cylinder-to-Cylinder Combustion Variation in an SI Engine

ASME 2012 Internal Combustion Engine Division Spring Technical Conference ◽

10.1115/ices2012-81187 ◽

2012 ◽

Cited By ~ 1

Author(s):

Mirko Baratta ◽

Stefano d’Ambrosio ◽

Daniela Misul ◽

Ezio Spessa

Keyword(s):

Diagnostic Tool ◽

Combustion Process ◽

Experimental Tests ◽

Test Point ◽

Pollutant Emissions ◽

Engine Operation ◽

Pressure Transducers ◽

Rate Analysis ◽

Spark Plug ◽

Wide Range

An experimental investigation and a burning-rate analysis have been performed on a production 1.4 liter CNG (compressed natural gas) engine fueled with methane-hydrogen blends. The engine features a pent-roof combustion chamber, four valves per cylinder and a centrally located spark plug. The experimental tests have been carried out in order to quantify the cycle-to-cycle and the cylinder-to-cylinder combustion variation. Therefore, the engine has been equipped with four dedicated piezoelectric pressure transducers placed on each cylinder and located by the spark plug. At each test point, in-cylinder pressure, fuel consumption, induced air mass flow rate, pressure and temperature at different locations on the engine intake and exhaust systems as well as ‘engine-out’ pollutant emissions have been measured. The signals correlated to the engine operation have been acquired by means of a National Instruments PXI-DAQ system and a home developed software. The acquired data have then been processed through a combustion diagnostic tool resulting from the integration of an original multizone thermodynamic model with a CAD procedure for the evaluation of the burned-gas front geometry. The diagnostic tool allows the burning velocities to be computed. The tests have been performed over a wide range of engine speeds, loads and relative air-fuel ratios (up to the lean operation). For stoichiometric operation, the addition of hydrogen to CNG has produced a bsfc reduction ranging between 2 to 7% and a bsTHC decrease up to the 40%. These benefits have appeared to be even higher for lean mixtures. Moreover, hydrogen has shown to significantly enhance the combustion process, thus leading to a sensibly lower cycle-to-cycle variability. As a matter of fact, hydrogen addition has generally resulted into extended operation up to RAFR = 1.8. Still, a discrepancy in the abovementioned conclusions was observed depending on the engine cylinder considered.

Download Full-text