Thanks for the your kind comment.
This LSHL is very interesting, I have not come across this over the years, however, it is quite common on diesel engines. For whatever the reason it is for, pre-ignition or emission. This is new to me. Did Ford explain why? I can only assume the same amount of fuel is shared with two shorter duration pulses to maintain correct fuel flow.
The aquamist system detects the duty cycle % of the fuel injector signal, multiple injection events will not cause error reading. I had the pleasure of spending many hours per day for the last three weeks on OseaD's car. It was for a different reason, I was tracking down the source of an interference with his help and patience.
During those sessions, we configured the aquamist controller to display fuel duty cycle %. He took some videos and the fuel idc is extremely smooth and progressive under different engine loads. So the answer is, we have no problem decoding the Ford's LSHL system.
Boost based only flow control may not be the best way to inject water/methanol in my opinion. Without the RPM and IAT information. It will not represent true engine load. Depending on your view on how important it is to match fuel flow. That will be another topic to discuss. What do you think?
Right. I totally agree that boost doesn't provide the full picture, and I love the idea of using IDC.
I do not know the full specifics of Ford's LSHL system (or even if that's what they truly call it. I got the terminology from Cobb!). I did some testing with Braden[email protected]
on enabling/disabling it to see if we could notice any difference or possible fueling benefits. He would probably be the most knowledgeable about the situation, but I hate bugging him too much as the less I bug him the more he can do his actual job
Our results were basically that it doesn't help any to disable it, and they have it for a reason. I suspect it's for soot buildup or pre-ignition, as the LSHL off tune does seem to have some soot puffs come out the back of the car. This would lead me to believe that it's timed very close to the spark ignition, similar to how a diesel uses a close pre-injection (and post injections) to tame soot buildup. While diesel ignites from compression, and we from spark, it would have the same effect of having a cool even fueling in the cylinder end gas to help prevent excess unburned fuel pockets causing soot buildup. It also has the added benefit of injecting cold fuel right when a pre-ignition event would happen, which is what I think might be the primary purpose.
I would think it would directly cut pulsewidth in half, but it could be that is just how the ECU side reports it.
Without LSHL turned on, the pulsewidth and load curve match beautifully, as seen here
With it turned on (the norm), you can clearly see the "halving" it does, implying two injection events, as seen here
I don't know if this is what the actual pulsewidth going to the injectors looks like though, but I'd assume they match up. I suspect as long as we set the threshold at about 3.5ms we'll be okay though, especially if we already got a guinea pig (thanks @OSeaD
!) that's tried it out for us
We won't have issues overfueling the engine on most single nozzle setups. There is a delay to the STFTs responding but overall the OEM ECU can easily accept 10-15% - perhaps 20% more fueling without needing fueling adjustments in the tune for it. Beyond that you will need to be a little careful how you bring in the extra fueling as it can cause some oscillations in the AFRs and OEM fueling as it adjusts to the sudden onset of extra fuel.
I think the scope of keeping WMI fueling within 20% of total additional fueling is reasonable and simple. Beyond that you'd have to start adjusting the OEM fueling side of things and since this car is speed density it is a little trickier than scaling down the MAF.
Makes sense. I'd suspect (based on the Aquamist guide) that using a 0.7mm or 0.8mm single nozzle would be sufficient for a big turbo setup with headroom and a 50/50 mix.
I'd assume that a tune based on 50/50 would have the spark map in the high load cells adjusted to account for the cooling/octane bump we see, but for the fueling we simply rely on the feedback to remove what I assume is the richness we would see from a setup?