Originally Posted by epoth
On the other hand, this system is actually a bit different than the 2d Aquamist setup. The Perrin PWI-1 does *not* use the High-Speed Valve from the 2d system. Instead it actually varies the duty cycle of the pump to vary the output of the system. It is anyone's guess as to how well this setup will work compared to the pump/HSV setup.
The system also does *not* use a manifold pressure switch to initiate the water injection process. Instead it initiates based on the Injector Duty Cycle. I'm going to leave it to more knowledgeable people than I to decide how that fact alone will affect the ease of tuning for the transition from injecting/not injecting.
Your ability to relate fragments of information is exceptional.
It is true that HSV has been omitted due to cost. We have tried for number of years to find a stainless material that has high corrosion resistance and good maganetic properties, but failed. The HSV will remain to be an expensive item - doesn't help us at all to complete against other pump speed based systems.
Perrin has identified a gap in the Aquamist systems, somewhere between a 1s and 2d. They urged us to look into creating a system that has all round performance without a high price tag. So the Perrin PWI-1 system was born. A year's work but we believe it will satisfy most demanding WIA users.
We have ruled out the pump with large motors due to its inability to track rapid change fuel duty cycles, so modulating the Aquamist piston pump is an ideal solution. Almost instant pressure build up, only takes 10ms to change flowrate (0-100%). As each pulse produces full pressure, there is less atomisation problem at low duty cycle.
Flowrate and duty cycle signal is closely tracked by the turbine flow sensor full time. Failsafe is inbuilt naturally.
Tracking the FIDC is good way to supplimenting and enhance the performance of normal pump fuel, that is the sole aim of this system. Inlet/incylinder cooling come free as a bonus.
It may not have the accuracy of the HSV nor can it be controlled by a third party EMS, it is 100% stand-alone system. I think at the price tag Perrin is asking, it will earn itself into a small niche in the market place.