The extra injectors are for the particulates in the exhaust.
I don't think that's right ...
but I am willing to be open minded if you have more info.
Here's what I understand is the issue, and how it was addressed. Up to now, Ford's EB engines only used DI. That allows for much higher compression ratios, which ups power and efficiency. The downside to DI is that there is no longer any fuel going down the intake tract, and cleaning/cooling the back of the intake valves. Without this cooling effect of gas vaporization in the intake tract, the intake valves run hotter, and yet still get a full dose of PCV oil impurities and EGR exhaust. So the lack of gas detergents in the intake tract allows more heat to bake the ever-present oil blow-by byproducts, with no aid from the detergents in the gasoline. Simply put; same amount of PCV junk, more heat, less cleaner. That makes for a bad combination. There are lots of 'tube vids showing the backs of intake valves in EB engines having a mound of carbon gunk on them.
So, Ford introduced this next-gen EB; it has the DI injectors AND multi-port injectors. I'm not sure what protocol is used to determine when each set is firing. Several opportunities exist:
- only DI fires
- only MPI fires
- DI fires prior to MPI sequentially; one finishes prior to the other coming open
- MPI fires prior to DI sequentially; one finishes prior to the other coming open
- DI and MPI fire in overlap; one before the other but overlapping in timing
- DI and MIP fire concurrently
I'm sure it's fairly complex. As the makers of tuners get this worked out, we'll know more.
But I don't think it has anything to do with particulate in the exhaust stream.
As I said, if you have more or different info, please share!
I'm very interested in this new engine and how it deals with the inherent problems.