Investigation of the Influence of Alternative Spark Plug Electrode Material on Ignition Behavior

Abstract

Robust engine operation with long maintenance intervals and low emissions is the key to meeting future engine requirements. At the same time, engines should be environmentally friendly, resource-friendly, and cost-effective to produce and operate. To meet these market requirements, a central component in engine development is the ignition system and in particular the spark plug. To increase the maintenance intervals of internal combustion engines, it is necessary to increase spark plug lifetime by reducing spark plug wear. The electrode materials used to date are often expensive and rare, and their mining is not without controversy. Successful use of alternative spark plug electrode materials which are available in large quantities, inexpensive, and more resistant to wear than existing materials with similar ignition behavior would advance engine development so it can meet further economic and environmental requirements. To this end, ceramic spark plug electrodes were investigated to determine their spark and ignition behavior as well as their wear. These materials seem to be an interesting alternative to existing spark plug electrode materials. This paper presents a spark plug with ceramic spark plug electrodes that achieves conditions similar to those of standard spark plugs in terms of secondary voltage trace and ignition behavior. Furthermore, it introduces a sophisticated method for scientific, cost-effective, and application-oriented development. Finally, it provides a promising outlook for the ignition behavior and combustion performance of engines with this spark plug.

Feasibility study on electrically conductive joining of MoSi2 electrodes for spark plugs

“…Figure 2A shows the development of a spark between the two MoSi 2 electrodes, which were successfully glued to the Inconel 600 parts of the standard spark plug. A trace of the secondary voltage confirmed good electrical conductivity and similar behavior compared to an original spark plug (see Figure 2B) for which a detailed interpretation of the test results can be found in 12 . Due to the successful experiments, the material qualified for further experiments under realistic conditions.…”

“…A trace of the secondary voltage confirmed good electrical conductivity and similar behavior compared to an original spark plug (see Figure 2B) for which a detailed interpretation of the test results can be found in. 12 Due to the successful experiments, the material qualified for further experiments under realistic conditions. During the singlecylinder engine tests, the engine was operated at 1500 RPM, and the load ramped up to full load over 1 h and 15 min.…”

“…Nevertheless, tests in real environments are essential due to the very complex interaction of temperature, pressure, fuel composition, exhaust gas, and combustion residues in the combustion chamber together with wear mechanisms on the electrode coming from the electric arc of the spark plug itself. [9][10][11] In this context, MoSi 2 seems to be a promising material for the application as spark plug electrode in large gas engines, 12 whereas long-term tests are still pending due to the limitations described above.…”

“…(A) Development of the electric arc between two MoSi 2 electrodes in a modified spark plug and (B) respective secondary voltage trace indicating a similar electrical behavior of the MoSi 2 electrode compared to the original one 12. …”