Prototype of the spark pług for ignition of natural gas-air mixture

This paper presents issues concerning the selection of spark plugs for engines fuelled with natural gas. There are discussed the specific conditions for proper ignition and combustion o f natural gas in SI engine. The new model of spark plug for ignition of natural gas-air mixture was designed and manufactured in collaboration with Iskra Zakłady Precyzyjne Sp. z o. o. from Kielce. The way of assessing of the performance of the new spark plug after test operation in a bus after 10 thousand km, 15 thousand km and 30 thousand km is presented. These tests allow preparing mass production of spark plugs for professional ignition system for SI engines fuelled with natural gas. New spark plugs will provide a longer service life compared to previously used. They also make it possible to eliminate the extinction of the arc between the electrodes and an electrical misfire in subsequent cycles of engine operation. As a consequence, fuel consumption reduction and reduction of emissions of unburned hydrocarbons into the atmosphere is expected. Apositive effect of the application of new spark plugs can be also longer engine service life. The introduction of the new spark plugs contributes to fulfil the strategy elaborated by EU which foresees the effective use ofalternativefuels, especially natur al gas which is good alternative for gasoline and diesel oil because of possibility of fulfilment of European emission and noise standards.