Fig displays the pilot valve and needle time histories for
9), because the needle is venules ballistic over the whole injector operative range, and the growth in s leads to an increase in the time available for the needle upstroke. As a consequence, the nozzle closure instant is delayed for fixed ET when s grows ( Fig. 10), since the needle has to cover a larger stroke. In general, radial thickness s has a greater effect on the nozzle closure delay (NCD) than on NOD, because both the discussed effects of s on xpv (at pilot-valve opening and closure) tend to enlarge the NCD.