March 1, 2015 (continued): Project "Complete Water Injection" Day 1 (continued)I then moved my attention to testing out the pump, solenoid, and injector. I don't know why but I took like a 45-degree picture, so the picture posted has been rotated and trimmed to get the water tank and injector in view.
Also here is a close-up of the injector. In the past I had only used a low pressure injection system with barbed fittings, but now I'm using high pressure with push / quick disconnect fittings. So I was still trying to gather up parts which is why there are a bunch of different adapters on my injector. I was just trying to test things out at this point.
Here is the setup I'm using:
Water Pump: SHURflow 60 psi pump, p/n 8009-541-236 - $70 on Amazon (
link). This is a tried a true pump for the DIY market: People are using them all over the place. They have a built-in and adjustable pressure switch which is handy when used with an accumulator (described below). There is also a 100 PSI version available but at the time I didn't know about it and bought this one. No regrets, it works great.
Solenoid: Generic made-in-China 1/4" electronic solenoid - $12 on Amazon (
link). The solenoid is used to prevent water from siphoning into the engine under vacuum. There are many better solenoids but for now I'm gonna give this one a shot. Need to make sure even just the basics are working before I can start fine tuning things. In the past I have used low pressure check-valves for this same reason, but I plan to have a constant pressure acting on the solenoid (described below) so for this DIY I need it to be electric.
UPDATE: This solenoid turned out to be a real PILE OF CRAP! Please see
reply #426 and DON'T BUY THIS $12 Amazon one. I urge you to drop $$ on a good quality solenoid as described in reply 426.
Accumulator: SHURflow Accumulator, p/n 181-201 - $40 on Amazon (
link). The accumulator is used to maintain a minimum set pressure at the front of the solenoid so that the moment the solenoid opens there is always an instant high pressure supply for the injector. Higher pressure = finer mist coming out of injector = more energy (heat) required to change from liquid to vapor.
What is the Accumulator for?
The way it works is that it has an internal bladder that is pressurized (I'm using my bicycle shock pump). This bladder applies pressure to the water so that as the water level drops it drops under a constant pressure. The pump's on-board pressure switch turns on at a low PSI and turns off at a high PSI. On the model I'm using, the low PSI is factory-set to 60 PSI, and the high PSI is adjustable. I've turned the adjuster screw two turns clock-wise to bump it's high PSI range up a bit (however at this time I've not confirmed what this is yet -- maybe 70 or 75 PSI) (I do have plans to install a pressure gauge as listed above). So with the accumulator, you pump it up to the same PSI as the pump's low switch point, which is 60 PSI, so that no matter what we always have at least a minimum of 60 PSI acting at the solenoid.
What is the purpose of the Accumulator?
The purpose is that the pump won't have to constantly cycle every time the solenoid is opened. The pump has an internal check valve so it can turn on and hold pressure against a closed solenoid. But the moment the solenoid is opened, the pressure rapidly drops causing the pump to kick on. Think of the accumulator as a Pressure Reserve. Because I am planning to use a programmable microcontroller to operate my water injection (with infinite trigger points) (planning to program a 10-point linear duty cycle), I plan to cycle the injector A LOT. Without the accumulator, the pump would be cycling like crazy shortening it's life span and increasing the current load on my electrical system. The accumulator is a great device to have!
The Nozzle: I'm currently using a stainless-steel 15 GPH @ 100 PSI full cone misting nozzle from McMaster Car, p/n 3178K47 (About $11,
click here). This Nozzle is manufactured In The USA by Hago and is labeled M15.
Click here for a Hago Nozzle Datasheet. I have also ordered p/n's 3178K46 and 3178K45 which are the 10 GPH and and 5 GPH flow rate nozzles. The way I've designed this provides for easy in-the-field swapping. All I need is a pair of pliers. I'll need to experiment with it to see what flow rate works best. I'm pretty sure the 15 GPH that I have is too big but it's the only nozzle I have at the moment so it will be tested first.
The Line: Polyethylene Plastic Tubing, 1/4" OD x 11/64" ID x 100 feet - $8 on Amazon (
link). Rated to 150 PSI and 140 degrees F. Should be plenty good!
The Fittings: I'm using a whole bunch of different fittings all found on Amazon. Search for "push to connect" and look for manufactures Legris and MettleAir. If you have any specific questions let me know. I just researched the specs for inlet and outlet port fittings and then searched for these accordingly on Amazon. For example
here is a 90-degree 3/8" NPT x 1/4" push-to-connect fitting for use at the water pump, and
here is a straight 1/4" NPT x 1/4" push-to-connect fitting used at the solenoid.
Sealing: I originally used teflon tape (I already had some, but
here is a link for reference), but I found that I had to tighten the fittings so much that I was afraid I was going to break something (as the pump and accumulator both has plastic housings) (maybe I wasn't using enough tape? I went around and around 2 or 3 times...). So I did the last few remaining fittings using my favorite gasket sealer, Permatex High Tack (p/n 80062 - $7 -
link). Not even a drop and I didn't have to excessively tighten the fittings. If I ever need to take any of the teflon fittings off then I'll be reassembling with High Tack.
Last note: One issue I had is that the accumulator for some reason uses huge 1/2" NPT ports and I could not find 1/2" NPT x 1/4" push-to-connect fittings. So I had to first get a pair of 1/2" NPT to 3/8" NPT bushings, and then I could use some 3/8" NPT x 1/4" push-to-connect fittings I had already ordered. We happened to have these bushings laying around at the shop, but for an Amazon example, see
this link.
And that's about it. You'll need to come up with your own means of triggering the solenoid. In the past I used an adjustable pressure switch, but I don't have any ordering or product links to help you. Search around for one and you should find it. For me it will be done digitally
And that was it for the first day. Got the tank mounted and got the pump and solenoid tested and some wiring figured out.
