https://youtu.be/1dijtRUZeLwAn engine innovation first conceived and tested by Sandia National Laboratories has attracted the attention of big business because of its potential to cost-effectively reduce emissions of soot and nitrogen oxides, encourage the use of renewable fuels, and maintain or improve engine performance.
Ducted fuel injection, developed by Charles Mueller at Sandia's Combustion Research Facility, is able to fine-tune the fuel-air mixture in an engine to the point of eliminating between 50 percent-100 percent of the soot depending on the engine's instantaneous speed and power level.
Just imagine no more regens and getting rid of most of the exhaust after treatment system. A huge cost savings on these cars and lower emissions more than likely plus a boost in power maybe. Sounds like a win/win. Only problem is we will probably never see it.Wow, the ducted fuel injection principles are awesome. Just a simple physical item placed around the injector more or less (and the injector itself I'm sure is altered to have a spray pattern that better lines up with the ducts).
The challenge with retrofits is there typically is very minimal room to anything else in the combustion chamber as it is. Valve reliefs are machined into the top of pistons because if they weren't, pistons would hammer the valves while the valves are closed... I found this out the hard way when I was attempting to figure out what was going on with this odd merging of two engines. Someone put a BEW bottom half with an ALH top half. BEW pistons do not have valve reliefs machined into them because the valves in the BEW head are designed to recess into the head a little. ALH and non-BEW PD heads have the valves protrude ever so slightly from the bottom of the head.
That engine was in fact hitting the valves with the valves closed... That's how little room there is.
Now, there's a smidge more room in commonrails with the wider combustion bowl and compression down to 16:1 instead of 18 or 19.5:1, but still, that ducting would have to almost be partly recessed back up into the head a little and require a different injector who's tip might not protrude into as far into the chamber as they currently do for many road-going diesels.
Where there's a will, there's a way I'm sure.
I'm not too worried about retrofits, but always good to see signs of relatively simple solutions that could kick diesel technology to the next level and maybe even simplify emissions aftertreatment systems.
Much more integrated-into-the-casting designs will eventually result, I'm sure. Just looking at the video of the flame fronts and seeing the chart of normal diesels, A/F ratio and the curve between soot and NOx generation and the much lower and nearly flat line of the ducted setup, hugely, hugely impressive difference this makes, especially for how simple a device it appears to be.
I suspect this may also have a very noticeable increase in efficiency too. I would not be surprised to see astounding differences in how little fuel a diesel uses with such a system.
I will be very, very curious to see the first OEM that goes into production with this and see how well it performs not only in terms of emissions, but power and economy as well.
Anybody remember pre-chambers? For something like this to survive in the severe heat and oxidising environment of a modern diesel, it will require cooling and need to be made from inconel. The whole thing will need to be buried in the head, like a pre-chamber, to properly cool. As a result, it will suffer the same high surface area heat loss (efficiency and starting problems) as a pre-chamber. Nice idea and probably works well in a low specific output test engine. I just can't see it working out in real life.Unless ... you re-think the way the injector sprays, and build something that achieves this function directly into the cylinder head itself.
Refashioning the injector nozzle for smaller engines will be tough, pictured looks like it would be for a very large engine, (power plant, shipping boat, something large!) places where a retrofit would be a better idea than replacement of the head.I'm wondering if you could build it into the injector- instead of minimising the tip of the nozzle, give it lots of mass then "core" a ring out axially and drill a larger outer hole and then the smaller EDM'd injection hole concentrically for each hole..
Someone like Bosio would need to view and tweak their design to be closer to the larger nozzle, but making micron sized holes is a very small process.I can definitely see this retrofittable to cargo ship diesel engines, trains, and large generators. A second generation could possibly retrofit to HD diesel OTR engines and if the specific application warranted the investment and trials.
Perhaps they can, but I suspect that there are at least these two critical design criteria:Someone like Bosio would need to view and tweak their design to be closer to the larger nozzle, but making micron sized holes is a very small process.