Some companies are making a go of it for the heavy truck industry... (Where you can get away with 20k install prices..)
Fierce Fuel Systems
However, they seem to hit the wall at around 30% emulsion percentages..I tried getting hold of some for my testing, but unfortunately they seem to be having growing pains for their company (AKA I am uncertain on their stability!)
I have been testing the standard water injection along with Hydrogen fairly heavily, and if using decent grade hydrogen (Not already full of water vapour at varying quantities from electrolysis!), it looks like the engines start to stumble at 40%+ injection rates..(3 x staged injectors to achieve this on a big rig)....
Have to be careful WHICH engines you install it on however..as some with the H20 sensors in the incorrect spots need more trickery to overcome
There are some tricks that need to be applied to achieve the above rates / volumes..which I can not disclose as yet unfortunately..These tricks would probably also apply to the emulsion formats..but for the price of the kits, including surfactants, and ongoing maintenance..I am leaning towards progression on a more simplistic WI methodology (Requires Computer control / H20 sensor integration / staging and a few things extra to work well from what we have seen..) However even without Hydrogen as an additional fuel, H20 seems to definitely work, with reduced engine temps / turbo temps, negligible decreases in HP during the normal rev range (Does reduce higher up), and a fairly huge displacement possible in diesel...
Pity the standard WI kits on the market are simply put..RUBBISH...some are glorified irrigation supplies..a few are much better than that (EG cooling mist), but they are more geared from what I can see towards performance markets, and still fail to interact on a few parameters correctly, leaving the fuel economy crowd missing out severely on their possibilities.