Interacting-sprays injection: A new concept for NOx and smoke reduction indiesel engines

In the past decade many in-cylinder injection approaches have been proposed for simultaneous reduction of NOx and smoke in diesel engines, with variou s degrees of success in operation. In this article, some results from a nov el and promising technique referred to as the interacting-sprays injection concept is presented A single-cylinder compression-ignition two-stroke rese arch engine with optically accessible head mounted an a high-speed CFR (coo perative fuel research) engine crankcase is used to investigate the combust ion and emission characteristics of this injection system. The interacting- sprays injection system produces two separate, independently controlled liq uid fuel spray injections with a good degree of adjustability with regard t o their fuel quantities and injection timings. The impingement schedule of the two sprays on each other at the right time and place inside the combust ion chamber is the key to the success of the interacting-sprays injection s ystem Results are presented that show the effects of the varied injection s ystem characteristics on the combustion and exhaust emissions (NOx and smok e). The effects of the injection timing and time separation between the fir st and second injections of the interacting-sprays injection system are exp lored. Conditions are identified for which a favorable influence on both sm oke and NOx production is observed A promising and sew injection system and strategy are therefore proposed as a result of the data acquired in this s tudy.