161 Understanding pilot pulse

Hi Andre, just a question with regard to the worked example. From the test performed, it seemed as though the pilot injection was optimized with the numbers you were using for both quantity and timing, without going to extremes and making minute changes. However when you effectively turned the pilot injection off, and torque plummeted, do you think optimizing the main injection timing would have brought the torque back up to previous levels?

I did read on here, I think it was a post by Ruud Visser, that in instances of high load and long injector duration, he has seen benefit in effectively turning off pilot injection in order to advance main injection enough to get all the fuel in earlier. I'm curious as to if this applies at lower loads as well (presumably at the expense of NVH and possibly emissions).

Cheers, Ben.

Yes it's quite likely that further optimisation of the fuel quantity and timing would have helped with the torque drop off. Optimising the fuel delivery and pilot pulse is an iterative process and you're correct that the pilot pulse is more crucial at lower rpm where diesel knock is more of an issue. It really does come down to your aims and what level of NVH you're happy with.