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This paper focuses on effect of rhodium addition on degradation behavior of Ir-10 mass％Rh alloy for a spark plug during oxidation at elevated temperatures. Oxidation tests were conducted at the temperature range from 1173 K to 1473 K in Ar-21％O2 gas mixture to clarify the effect of rhodium addition on degradation behavior of the alloy. As a result, there are three effects of rhodium addition to prevent the alloy from the degradation: (1) dissolution of rhodium into iridium oxide scale at below 1273 K, which decreases activity of iridium oxide in the oxide scale, (2) dissolution of rhodium into the alloy at above 1273 K, which decreases activity of iridium in the alloy and (3) formation of rhodium oxide, which decreases surface area of the alloy. All effects contribute to decrease vapor pressure of volatile iridium oxide, resulting in suppression of the degradation. [ABSTRACT FROM AUTHOR]

This paper analyses the influence of the type of electrode in a spark plug on exhaust gas emission. The objects of the research were the following vehicles of different years of production: the Volkswagen Beetle 1300, the Honda Nighthawk 650, the BMW e46 318i, the Hyundai i10, and the Audi A4 B6. The vehicles were powered by petrol and LPG. Spark plugs were selected for the vehicles, with different kinds of construction for the main electrodes and different numbers of poles but with similar heat values. A comparative analysis of the composition of the exhaust gas mixture was performed, depending on the set of spark plugs used. The amount of CO, HC, CO2, and O2 emissions was analysed. The results were compared with the applicable exhaust gas emission standards. Both in the case of E5 95 petrol and LPG gas, lower exhaust gas emissions were observed when iridium spark plugs were used. [ABSTRACT FROM AUTHOR]

The study investigated the impact of gasoline and ethanol-gasoline blend E5 on motorcycle engine wear, deposits, performance, and emissions following an endurance run test. The dimensions, appearance of the major components, and engine performance and emission have been measured to compare. Compared to the E0 case, the ring grooves and piston's skirt in the case of E5 fueling were relatively cleaner. The piston skirt wear was 0.06 mm for E0 and 0.04 mm for the E5 case. After the endurance run test, the mass of deposits on the intake valves and valve seats was 247.3 mg for the E0 and 323.8 mg for the E5 case. In addition, the electrode gap of the spark increased gradually up to 50% after 200 h of running for E0, but the gap was only 31.5% raised for E5. A slight increase of 1.63% and 1.51% on average brake power was observed for E0 and E5 cases after 100 h of operation. However, the observed power drop of 2.55% for E0 and 1.86% for E5 as the test engines reached 200 h of operation. The CO emission was reduced by 1.73% to 4.81% for E0-engine and 0.58% to 2.35% for E5-engine after 100 h. But, after 200 h, CO increased 1.12% to 8.07% for E0 and 0.24% to 0.38% for the E5-engine within speeds 4000 rpm to 7000 rpm. HC increased by 4.69% to 14.14% for the E0-engine and 1.55% to 6.98% for the E5-engine after the endurance run test. There was an unpredictable tendency of NOx emission after 100 h and 200 h of operation for both test engines. [ABSTRACT FROM AUTHOR]

Copyright of Dilemas Contemporáneos: Educación, Política y Valores is the property of Dilemas Contemporaneos: Educacion, Politica y Valores and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The reduction of greenhouse gas emissions and the effort of carbon neutrality require the improvement of spark-ignition engines in terms of efficiency and capability to operate on renewable fuels. The electrode wear of spark plugs, used for ignition of novel fuels and lean mixtures, emerges as a significant challenge in this transition. Understanding the physical mechanism and influence of spark operation parameters of the wear process is thus important. Compared to the conventional methodology of performing long-term wear tests, laser-based optical diagnostics methods are capable of assessing electrode wear during one single or a few spark discharges. In this work, the necessary initial steps required for performing optical investigations using laser-induced fluorescence (LIF) are presented. Several excitation pathways of nickel atoms were investigated, and 336.96 nm was identified as the optimal one. This excitation approach yielded emissions between 338.75 and 353.58 nm, effectively avoiding the major interference from N2 plasma emission in spark discharges. Additionally, a linear relationship in fluorescence signal intensity with excitation energy up to 400 µJ was observed. These findings indicate the potential of LIF for in situ diagnostics of electrode wear, contributing to engine development in both efficiency and compatibility with sustainable fuels. [ABSTRACT FROM AUTHOR]

AbstractThe present study aims to synthesis and characterization of spinel coating for spark plug aero-engine application. At first spinel coatings were synthesized by mechanical alloying. The different spinel coatings with spinel different composition and modulation were applied on alumina substrate. The phase content of the samples was characterized by X-ray diffraction (XRD) method. The microstructure and thickness of the coatings were analyzed by scanning electron microscopy. Nano-hardness and Young’s modulus of the coating were measured by nano-indentation method. The electrical resistance of the coating was studied at different temperatures. The electrical wear resistance of the coating was evaluated by spark method. The XRD method confirmed the synthesis of copper based spinels. The coatings had a thickness of 19-22 μm with proper density. The average nano-hardness of the coatings was 10 GPa. The wear rate after 140000 of spark was less than 1% of coating weight. It was also found that the optimum modulation of the multilayer coating is 4 successive layers composed of CuFe2O4+CuCr2O4, followed by two layer of CuCr2O4 and again CuFe2O4+CuCr2O4 layer. The ratio of the components in the composite layers were 50:50 wt.%

Upcoming gasoline engines should run with a larger number of fuels beginning from petrol over methanol up to gas by a wide range of compression ratios and a homogeneous charge. In this article, the microwave (MW) spark plug, based on a high-speed frequency hopping system, is introduced as a solution, which can support a nitrogen compression ratio up to 1:39 in a chamber and more. First, an overview of the high-speed frequency hopping MW ignition and operation system as well as the large number of applications are presented. Both gives an understanding of this new base technology for MW plasma generation. Focus of the theoretical part is the explanation of the internal construction of the spark plug, on the achievable of the high voltage generation as well as the high efficiency to hold the plasma. In detail, the development process starting with circuit simulations and ending with the numerical multiphysics field simulations is described. The concept is evaluated with a reference prototype covering the frequency range between 2.40 and 2.48 GHz and working over a large power range from 20 to 200 W. A larger number of different measurements starting by vector hot- $S_{11}$ measurements and ending by combined working scenarios out of hot temperature, high pressure and charge motion are winding up the article. The limits for the successful pressure tests were given by the pressure chamber. Pressures ranged from 1 to 39 bar and charge motion up to 25 m/s as well as temperatures from 30° to 125°. [ABSTRACT FROM AUTHOR]

This paper analyses the influence of the type of electrode in a spark plug on exhaust gas emission. The objects of the research were the following vehicles of different years of production: the Volkswagen Beetle 1300, the Honda Nighthawk 650, the BMW e46 318i, the Hyundai i10, and the Audi A4 B6. The vehicles were powered by petrol and LPG. Spark plugs were selected for the vehicles, with different kinds of construction for the main electrodes and different numbers of poles but with similar heat values. A comparative analysis of the composition of the exhaust gas mixture was performed, depending on the set of spark plugs used. The amount of CO, HC, CO2, and O2 emissions was analysed. The results were compared with the applicable exhaust gas emission standards. Both in the case of E5 95 petrol and LPG gas, lower exhaust gas emissions were observed when iridium spark plugs were used.

The objective of this study is to apply an improved Faster-RCNN model in order to solve the problems of low detection accuracy and slow detection speed in spark plug defect detection. In detail, an attention module based symmetrical convolutional network (ASCN) is designed as the backbone to extract multi-scale features. Then, a multi-scale region generation network (MRPN), in which InceptionV2 is used to achieve sliding windows of different scales instead of a single sliding window, is proposed and tested. Additionally, a dataset of X-ray spark plug images is established, which contains 1,402 images. These images are divided into two subsets with a ratio of 4:1 for training and testing the improved Faster-RCNN model, respectively. The proposed model is transferred and learned on the pre-training model of MS COCO dataset. In the test experiments, the proposed method achieves an average accuracy of 89% and a recall of 97%. Compared with other Faster-RCNN models, YOLOv3, SSD and RetinaNet, our proposed new method improves the average accuracy by more than 6% and the recall by more than 2%. Furthermore, the new method can detect at 20fps when the input image size is 1024×1024×3 and can also be used for real-time automatic detection of spark plug defects. [ABSTRACT FROM AUTHOR]

An experimental study of ignition and combustion of a propane/air mixture is carried out, and the efficiency of two ignition systems is compared. The first one is the traditional technology with conventional spark plugs, and the second one is a system with microwave initiated streamer discharges. In both cases, the ignition sources, spark plugs or streamer discharges are distributed along the surface of the combustion chamber. A subcritical streamer discharge is initiated on the surface of the circular tube using a half-wave resonator when the intensity of the electric field is much smaller than the breakdown intensity because ability of electromagnetic vibrators to initiate air breakdown has a resonant character. For the initiated streamer discharge, intensity of microwave radiation is significantly lower than the breakdown intensity. The results obtained for a new microwave ignition system of a fuel/air mixture are presented and compared with an ignition system based on spark plugs. Comparative analysis is given for different initial pressures and composition of fuel/air mixture. The time of propagation of the flame front is compared, as well as the rate of pressure increase in the combustion chamber, depending on the initial pressure and the composition of the mixture. The optimal fuel/air equivalence ratio, which provides the highest pressure and the highest rate of pressure rise in the combustion chamber, is determined. A comparative assessment of the energy efficiency of each of the approaches applied to the ignition of the fuel/air mixture is performed. The results obtained could potentially be useful to improve reliability of plasma-assisted ignition systems and flight safety. • Streamer discharge provides instantaneous volumetric ignition of the mixture. • Stable ignition of lean/richmixtures in air flows is demonstrated. • Effect of fuel/air ratio on combustion efficiency is investigated. • Streamer discharge yields improvement of combustion speed and efficiency. [ABSTRACT FROM AUTHOR]

Copyright of Przegląd Elektrotechniczny is the property of Przeglad Elektrotechniczny and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Ceramic insulators for spark plugs are important components responsible for the dielectric barrier to generate high-voltage pulses required to ignite the air–fuel mixture and for providing mechanical support to the center electrode. To ensure a high degree of reliability, many manufacturers apply corrugation patterns to the glazed upper part of an insulator to prevent flashover and parasitic discharges as well as to reduce the leakage current. The corrugation pattern design based mostly on simple cylindrical and conical shapes has changed very little over the years. This gives rise to the question whether an application of more sophisticated curves such as spherical, polynomial, or exponential can improve the surface resistance of a ribbed spark plug insulator. Quantitative analysis based on form factor and leakage distance calculations was used as a design method to optimize the shape of the spark plug insulator and its pollution performance. Furthermore, a novel concept of concave insulator corrugation patterns formed by quadratic and exponential functions was proposed and discussed as an alternative solution suitable for practical application. It was found that insulator ribs completed with supplementary concave corrugation ensure a longer leakage distance than conventional patterns. According to the results of calculations and measurements performed on three-dimensional printed samples, it was stated that the novel concave corrugation patterns can significantly increase the surface resistance of spark plug insulators. [ABSTRACT FROM AUTHOR]

To reduce the errors caused by traditional human visual inspection and improve the efficiency of spark plug defect detection, a spark plug defect detection system was designed based on discharge detection technology and machine vision technology. The spark plug defect detection system was composed of industrial computer, NI DAQ data acquisition card, IGBT driver board, IGBT module, ignition coil, voltage dividing module and industrial camera. Pulse width modulation technology and electromagnetic induction principle were used to apply high voltage to spark plug. The location information of spark discharged by spark plug under high voltage output of the ignition coil was captured to detect the defect in ceramic parts. The experimental results show that the high voltage output of the spark plug defect detection system is safe and measurable, and the detection accuracy is as high as 95%, which meets the actual application requirements of spark plug defect detection. [ABSTRACT FROM AUTHOR]

In this study, the performance of different spark plugs was tested with varied spark gap sizes in a spark-ignited engine. Gasoline fuel was enriched with hydrogen and methanol to evaluate how much they affect the performance of the engine. The engine tests were performed with a four-stroke, single-cylinder, naturally aspirated, variable compression ratio (VCR) spark ignition engine. 1500 rpm engine speed and MBT for spark timing were applied throughout all experiments. Iridium, platinum and conventional (copper) spark plugs were tested using 3 different spark plug gaps (SPG) (0.6 mm, 0.8 mm, 1 mm). Depending on the experimental condition, hydrogen was added with 3 l/min of flow rate and methanol was used with 10% of volume fraction in the total liquid fuel. As for performance criteria, brake power (BP) and brake specific fuel consumption (BSFC) values were obtained from the test engine. According to the findings, platinum and iridium spark plugs had shown better performance than conventional spark plugs. The increment of SPG size improved the performance of the engine, too. On the other hand, despite methanol addition to gasoline fuel reduced performance, this loss could be compensated by hydrogen enrichment. Additionally, multiple linear regression (MLR) technique was applied through experimental results to obtain a linear relationship between explanatory variables (inputs) and response variables (outputs). An MLR model was set with four selected input variables (spark plug type, hydrogen flow rate, methanol ratio, and spark gap) to estimate BP and BSFC. Prediction equations showed that experimentally obtained results were in good agreement with MLR results. • SPG was tested with platinum, iridium and copper spark plugs. • Gasoline, methanol and hydrogen fuels were used. • Platinum and iridium spark plugs are effective on increasing performance. • Methanol deteriorates the engine performance. • Increment of SPG and H 2 increases performance characteristic. [ABSTRACT FROM AUTHOR]

Following rapid depletion of fossil fuels and growing efficiency concerns enforce researchers to enhance combustion quality and find alternative fuels for SI engines. For this purpose, various spark plugs are available in the market with different electrode materials. However, they have not been tested together with different engine parameters. In this work, a variable compression ratio (VCR) spark-ignited engine equipped with different spark plugs (conventional, iridium and platinum) tested to determine performance values of brake power and brake specific fuel consumption. Effects of hydrogen enrichment (0%, 2% and 4% by volume fraction) and VCR (8.5:1 and 10:1) were applied to the engine at engine speeds of 1200, 1500 and 1800 rpm during experiments. The results revealed that higher performance values attained with iridium and platinum spark plugs comparing with the conventional spark plug at all hydrogen fractions, engine speeds and compression ratios. Besides that platinum spark plug increased the performance of the test engine more than iridium one. [ABSTRACT FROM AUTHOR]

This work is to study the plasma application using a capacitive discharge ignition capable of using the plasma jet which belongs to the non-thermal plasma physic. A plasma-jet spark plug was designed to combine a discharge chamber including an insulator and expanding the plasma area. The nonresistance was applied to acting the interference suppression of a plasma-jet spark plug to ensure the high energy generated at a DC-DC converter. An ANSYS FLUENT program was used to conduct analyzing combustion progress. The combustion simulation model is composed of configurations of a spark plug, a lambda sensor, and an internal combustion chamber. Resultantly, the minimum value of the combustion pressure is verified at λ = 1.6, and the plasma jet has higher values in the order of 2, 3, and 4 bar than the conventional models due to having a fast reaction. Consequently, the plasma jet has advantageous in combustion diffusivity in comparison to the conventional spark plug since the negative electrode of the cathode is not designed in front of a jet plug. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Test & Measurement Technology is the property of Publishing Center of North University of China and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A cold-extruded spark plug iron shell is assembled by hot riveting and then laterally brittle cracking at the expansion groove. In order to investigate the cause of failure, a comprehensive microscopic analysis was performed by using an optical microscope, a scanning electron microscope, a microhardness tester, and a hydrothermal analyzer. The results show that the machining of the inner wall of the iron shell is obvious and there is a small amount of rust. Manually opening the failed sample, it reveals that the originating source is located on the subsurface close to the inner wall, and the entire cross section has an intergranular fracture, and there are a large number of secondary cracks. The thickness of the electroplated nickel layer of the sample is relatively thin, the local thickness of the inner wall is less than 1 μm, and a small amount of iron oxide remains in the plating layer. The grain size is 7.4, and the hardness of the longitudinal section of the expansion tank fluctuates greatly. The hardness of the coarse grain area is less than 150 HV, and the front of the hot rivet is about 230 HV. The diffusion hydrogen content of the failed sample is 0.042 mg/m3. It is considered that the cause of the failure sample is the coupling of the phase transition stress and the residual stress generated by the increasing electroplating hydrogen, resulting in delayed cracking at the weakest expansion groove in the iron shell. [ABSTRACT FROM AUTHOR]

The paper analyses the possibilities of treating the ignition cable in the internal combustion engine as a distributed parameter system. It presents the experimental verification of computer simulations of signal propagation generated by ignition systems in the ignition cables, modelled by the distributed parameter system. The tests conducted to determine the wave parameters of ignition cables, as well as the results of numerical simulations and their experimental verifications, are presented. It is concluded that the modelling of the ignition cable by means of a long line gives positive results that can be used for the design of a spark plug with impedance equal to wave impedance of the ignition cable.

The paper analyses the possibilities of treating the ignition cable in the internal combustion engine as a distributed parameter system. It presents the experimental verifi- cation of computer simulations of signal propagation generated by ignition systems in the ignition cables, modelled by the distributed parameter system. The tests conducted to deter- mine the wave parameters of ignition cables, as well as the results of numerical simulations and their experimental verifications, are presented. It is concluded that the modelling of the ignition cable by means of a long line gives positive results that can be used for the design of a spark plug with impedance equal to wave impedance of the ignition cable. [ABSTRACT FROM AUTHOR]

A spark plug calorimeter is introduced for quantifying the thermal energy delivered to unreactive gas surrounding the spark gap during spark ignition. Unlike other calorimeters, which measure the small pressure rise of the gas above the relatively high gauge pressure or relative to an internal reference, the present calorimeter measured the differential rise in pressure relative to the initial pressure in the calorimeter chamber. By using a large portion of the dynamic range of the chip-based pressure sensor, a high signal to noise ratio is possible; this can be advantageous, particularly for high initial pressures. Using this calorimeter, a parametric study was carried out, measuring the thermal energy deposition in the gas and the electrical-to-thermal energy conversion efficiency over a larger range of initial pressures than has been carried out previously (1–24 bar absolute at 298 K). The spark plug and inductive ignition circuit used gave arc-type rather than glow-type discharges. A standard resistor-type automotive spark plug was tested. The effects of spark gap distance (0.3–1.5 mm) and ignition dwell time (2–6 ms) were studied for an inductive-type ignition system. It was found that energy deposition to the gas (nitrogen) and the electrical-to-thermal energy conversion efficiency increased strongly with increasing gas pressure and spark gap distance. For the same ignition hardware and operating conditions, the thermal energy delivered to the gap varied from less than 1 mJ at 1 atm pressure and a gap distance of 0.3 mm to over 25 mJ at a pressure of 24 bar and a gap distance of 1.5 mm. For gas densities that might be representative of those in an engine at the time of ignition, the electrical-to-thermal energy conversion efficiencies ranged from approximately 3% at low pressures (4 bar) and small gap (0.3 mm) to as much as 40% at the highest pressure of 24 bar and with a gap of 1.5 mm.

Inconel 601 is one material of choice for intermediate- to high-temperature protective coatings for spark plugs’ ground electrodes. Production of ground electrodes of spark plugs implies the following operations: the tamping of the copper core in an Inconel 601 cup, cold-forming of the assembly, annealing, welding, and bending of the final spark plug. On the production line, the use of Inconel 601 as a protective coating for ground electrodes leads to possible cracking in the welded area after bending. In the present paper, possible causes of cracking are analyzed. It is clearly shown that a combination of Copper –Inconel interface oxidation, Inconel yielding during the heat treatment, and micro-movements during bending lead to cracks in the welded area of the ground electrode. First, the detrimental effect of gaps, between Copper and Inconel 601, is shown experimentally. Second, a thermo-mechanical analysis combined with SEM (Scanning Electron Microscopy) observations identified the annealing treatment and interface oxidation as the main cause of gaps. Third, bending simulations show the relation between these gaps and cracking. Finally, a new ground electrode design, preventing cracks, is suggested.