Characterization and Mitigation of Spark Plug Electrode Erosion in Natural Gas and Automotive Engine Applications

2007 ◽  
Author(s):  
H. T. Lin ◽  
M. P. Brady ◽  
M. D. Kass ◽  
T. J. Theiss ◽  
N. Domingo ◽  
...  
Keyword(s):  
Natural Gas ◽  
Oxidation Resistance ◽  
Electrode Materials ◽  
Elevated Temperatures ◽  
Microstructural Characterization ◽  
Electrode Erosion ◽  
Automotive Engine ◽  
Reciprocating Engine ◽  
Spark Plug ◽  
Early Results

Microstructural characterization was conducted for laboratory gasoline and natural gas reciprocating engine tested spark plug electrodes made from a range of model, developmental, and commercially available electrode alloys. These alloys were selected to explore the effects of differing electrode alloy thermal, chemical, and mechanical characteristics on erosion resistance, and were tested with and without sparking surface alloy insert pads (platinum group and novel Cr-based alloys). Extensive internal oxidation and cracking were observed in both gasoline and natural gas engine tests, indicative of an inherent degree of susceptibility of currently-used electrode materials when heated to elevated temperatures, no matter what the ignition conditions. Highly-alloyed heat-resistant alloys with excellent oxidation resistance in many high-temperature environments suffered from increased rates of erosion, as the gains in oxidation resistance appear to have been offset by hotter running temperatures resulting from decreased electrode alloy thermal conductivity. Promising early results were obtained with a novel Cr-6MgO-0.5Ti-0.3La2O3 insert pad electrode alloy, investigated as an alternative to Pt- or Ir- base alloys, which showed little erosion and good resistance to cracking and oxidation.

Development of an Open Path Laser Ignition System for a Large Bore Natural Gas Engine: Part 1 — System Design

2005 ◽  
Author(s):  
David L. Ahrens ◽  
Azer P. Yalin ◽  
Daniel B. Olsen ◽  
Gi-Heon Kim
Keyword(s):  
Natural Gas ◽  
Pollutant Emissions ◽  
Electrode Erosion ◽  
Laser Ignition ◽  
Ignition System ◽  
Gas Engine ◽  
Natural Gas Engine ◽  
Spark Plug ◽  
Engine Part ◽  
Beam Delivery

Using a laser, as opposed to a conventional (electrical) spark plug, to create a combustion initiating spark is potentially advantageous for several reasons: flexibility in choosing and optimizing the spark location, in particular to move the spark away from solid heat sinks; production of a more robust spark containing more energy; and obviation of electrode erosion problems. These advantages may lead to an extension of the lean limit, an increase in engine thermal efficiency, and the concomitant benefits of reduced pollutant emissions. This paper presents the design of a laser ignition system appropriate for a large bore natural gas engine. Design considerations include: optimization of spark location, design of beam delivery system and optical plug, and mitigation of vibration and thermal effects. Engine test results will be presented in the second paper of this two-paper series.

Development of an Open Path Laser Ignition System for a Large Bore Natural Gas Engine: Part 2 — Single Cylinder Demonstration

2005 ◽  
Author(s):  
David L. Ahrens ◽  
Daniel B. Olsen ◽  
Azer P. Yalin
Keyword(s):  
Natural Gas ◽  
Combustion Stability ◽  
Electrode Erosion ◽  
Laser Ignition ◽  
Engine Test ◽  
Test Results ◽  
Ignition System ◽  
Gas Engine ◽  
Natural Gas Engine ◽  
Spark Plug

Using a laser, as opposed to a conventional (electrical) spark plug, to create a combustion initiating spark is potentially advantageous for several reasons: flexibility in choosing and optimizing the spark location, in particular to move the spark away from solid heat sinks; production of a more robust spark containing more energy; and obviation of electrode erosion problems. In this paper we present the on-engine test results of the laser ignition system on a large bore natural gas engine. Test results include: mass fraction burn duration, hydrocarbon emissions data, and combustion stability comparisons to the conventional spark plug ignition system. Design and spark location considerations for the laser ignition system were presented in the first paper of this two-paper series.

Phase transformation and layer evolution in molybdenum disilicide-silicon carbide nanolayered coatings

1994 ◽  
Vol 52 ◽  
pp. 538-539
Author(s):  
H. Kung ◽  
T. R. Jervis ◽  
J.-P. Hirvonen ◽  
M. Nastasi ◽  
T. E. Mitchell ◽  
...  
Keyword(s):  
Phase Transformation ◽  
High Temperature ◽  
Oxidation Resistance ◽  
Elevated Temperatures ◽  
Matrix Material ◽  
Molybdenum Disilicide ◽  
High Temperature Strength ◽  
Cross Sectional ◽  
Good Oxidation Resistance ◽  
Structural Applications

MoSi2 is a potential matrix material for high temperature structural composites due to its high melting temperature and good oxidation resistance at elevated temperatures. The two major drawbacksfor structural applications are inadequate high temperature strength and poor low temperature ductility. The search for appropriate composite additions has been the focus of extensive investigations in recent years. The addition of SiC in a nanolayered configuration was shown to exhibit superior oxidation resistance and significant hardness increase through annealing at 500°C. One potential application of MoSi2- SiC multilayers is for high temperature coatings, where structural stability ofthe layering is of major concern. In this study, we have systematically investigated both the evolution of phases and the stability of layers by varying the heat treating conditions.Alternating layers of MoSi2 and SiC were synthesized by DC-magnetron and rf-diode sputtering respectively. Cross-sectional transmission electron microscopy (XTEM) was used to examine three distinct reactions in the specimens when exposed to different annealing conditions: crystallization and phase transformation of MoSi2, crystallization of SiC, and spheroidization of the layer structures.

INCONEL 702

Alloy Digest ◽  
1958 ◽  
Vol 7 (3) ◽  
Keyword(s):  
Corrosion Resistance ◽  
Physical Properties ◽  
Tensile Properties ◽  
Oxidation Resistance ◽  
Elevated Temperatures ◽  
Base Alloy ◽  
Heat Treating ◽  
Nickel Base Alloy ◽  
International Nickel Company ◽  
Nickel Base

Abstract INCONEL 702 is a nickel-base alloy having moderate strength with exceptional oxidation resistance at elevated temperatures. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as creep. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Ni-40. Producer or source: International Nickel Company Inc..

Ignition System Designed to Extend the Plug Life, and the Lean Limit in a Natural Gas Engine

2003 ◽  
Author(s):  
A. K. Chan ◽  
S. H. Waters
Keyword(s):  
Natural Gas ◽  
Engine Performance ◽  
Ignition System ◽  
Gas Engine ◽  
Natural Gas Engine ◽  
Dc System ◽  
Spark Plug ◽  
Long Duration ◽  
Discharge Duration ◽  
Lean Limit

An ignition system that is based on the alternating (AC) rather than the traditional direct (DC) current in the spark plug discharge has been developed at the Caterpillar Technical Center. This system can generate a long duration discharge with controllable power. It is believed that such an ignition system can provide both a leaner operating limit and a longer spark plug life than a traditional DC system due to the long discharge duration and the low discharge power. The AC ignition system has successfully been tested on a Caterpillar single cylinder G3500 natural gas engine to determine the effects on the engine performance, combustion characteristics and emissions. The test results indicate that while the AC ignition system has only a small impact on engine performance (with respect to a traditional DC system), it does extend the lean limit with lower NOx emissions. Evidences also show the potential of reduce spark plug electrode erosions from the low breakdown and sustaining discharge powers from the AC ignition system. This paper summarizes the prototype design and engine demonstration results of the AC ignition system.

Comprehensive design methodology for an engine journal bearing

2000 ◽  
Vol 214 (4) ◽  
pp. 401-412 ◽  
Author(s):  
H Hirani ◽  
K Athre ◽  
S Biswas
Keyword(s):  
Film Thickness ◽  
High Speed ◽  
Design Methodology ◽  
Design Procedure ◽  
Maximum Pressure ◽  
Connecting Rod ◽  
Automotive Engine ◽  
Reciprocating Engine ◽  
High Power Output ◽  
Minimum Film Thickness

The trend towards high power output, high speed and low power loss in engines requires a better understanding of bearing behaviour. Research in this area is directed more towards different aspects involved in bearing analyses, rather than providing a comprehensive guideline on design of bearing. This effort compiles the design methodology for selection of diametral clearance and bearing length by limiting the minimum film thickness, maximum pressure and temperature. The design procedure is summarized on the basis of the existing rapid bearing analyses for evaluation of the journal trajectory, minimum film thickness and maximum pressure and simplified thermal analysis. A flow chart is provided for step-by-step bearing design. Finally, two case studies of engine bearings are described: one investigates the VEB bigend connecting-rod bearing for a large industrial reciprocating engine and the other a main crankshaft bearing for an automotive engine. The methodology translates into easy-to-use expressions and the overall procedure is outlined, using practical data to demonstrate how this can be employed effectively by users.

Evaluation of Spark Plug and Timing Configurations on the Fuel Consumption, Combustion Stability, and Emissions of a Large-Bore, Two-Stroke, Natural Gas Engine

2016 ◽  
Author(s):  
Derek Johnson ◽  
Marc Besch ◽  
Nathaniel Fowler ◽  
Robert Heltzel ◽  
April Covington
Keyword(s):  
Natural Gas ◽  
Fuel Consumption ◽  
Combustion Engine ◽  
Engine Performance ◽  
Combustion Stability ◽  
Oxides Of Nitrogen ◽  
Natural Gas Engines ◽  
Fuel Delivery ◽  
Spark Plug ◽  
Trade Offs

Emissions compliance is a driving factor for internal combustion engine research pertaining to both new and old technologies. New standards and compliance requirements for off-road spark ignited engines are currently under review and include greenhouse gases. To continue operation of legacy natural gas engines, research is required to increase or maintain engine efficiency, while reducing emissions of carbon monoxide, oxides of nitrogen, and volatile organic compounds such as formaldehyde. A variety of technologies can be found on legacy, large-bore natural gas engines that allow them to meet current emissions standards — these include exhaust after-treatment, advanced ignition technologies, and fuel delivery methods. The natural gas industry uses a variety of spark plugs and tuning methods to improve engine performance or decrease emissions of existing engines. The focus of this study was to examine the effects of various spark plug configurations along with spark timing to examine any potential benefits. Spark plugs with varied electrode diameter, number of ground electrodes, and heat ranges were evaluated against efficiency and exhaust emissions. Combustion analyses were also conducted to examine peak firing pressure, location of peak firing pressure, and indicated mean effective pressure. The test platform was an AJAX-E42 engine. The engine has a bore and stroke of 0.216 × 0.254 meters (m), respectively. The engine displacement was 9.29 liters (L) with a compression ratio of 6:1. The engine was modified to include electronic spark plug timing capabilities along with a mass flow controller to ensure accurate fuel delivery. Each spark plug configuration was examined at ignition timings of 17, 14, 11, 8, and 5 crank angle degrees before top dead center. The various configurations were examined to identify optimal conditions for each plug comparing trade-offs among brake specific fuel consumption, oxides of nitrogen, methane, formaldehyde, and combustion stability.

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