MY Water Injection System

[teoman]

I am considering doing water injection on a turbo diesel engine and while doing research i thought that it would be a good idea to keep a "blog" of it on here. I am not interested in performance but fuel economy, increase boost without melting anything. Once i get my system tuned in, i plan on getting the car tuned as well from where I shall be working with the tuner for some time to get the maximum benefit.

I hope that it is not a big no-no to post links to parts i intend on buying. I cannot use ebay or amazon they do not ship to my country anymore so I will probably be using aliexpress.

In my system I want to use a fuel injector so that i can control the flow more precisely and i have some ideas on using compressed air instead of a pump (mainly because i am a diver and I have lots of compressed air tanks).

I also intend on tapping in to the canbus to make the most intelligent system that i create so i will be using canbus to obtain the rpms and boost pressure to calculate the amount of water to add.

The car (I have not bought it yet) can be:
1.2 TDI VW Polo 2013
1.6 TDI VW Passat 2011
3.0CRD Grand Cherokee Jeep 2006
ML320CDI Mercedes 2006

I am still confused on what to get as this will also be my daily ride. The bigger cars are more appealing but i must be able to get the fuel consumption low to be able to enjoy it. Water injection, alternator delete and some aero mods will be done.

[Daox]

I've heard of water injection on gasoline engines to increase fuel economy (to essentially stay in closed loop and avoid fuel enrichment), but I'm not familiar with using it on diesel engines to increase fuel economy. What is the reasoning there?

[teoman]

As the water passes from liquid to gas there is a great volume change (or pressure change). And you can increase boost pressures while keeping the air charge cool and also keeping the engine components cool.

[Harlan]

Using a Ev-14 fuel injector. They will run water long term with few problems. Just make sure to pull them every few months, soak them in vinegar, and flow test them. Also only use pure water, not tap water.

You can get all the data you need off the CAN bus, however that prevents you from reading data with a scanner at the same time. I would recomend taking a 0-5v input off the MAF sensor or using RPM and MAP for speed density. I have used all three methods and am currently using speed density based in my build.

Originally Posted by teoman

As the water passes from liquid to gas there is a great volume change (or pressure change). And you can increase boost pressures while keeping the air charge cool and also keeping the engine components cool.

Remember if you use too much water you are turning a diesel cycle into a Rankine cycle. The phase change of the water takes away usable heat and puts it out the tailpipe. Use only as much water as you need or you will lose efficiency (power).

[teoman]

Thank you for the reply.

What pressure do you recommend for the EV14 injectors?

I found the following which are relatively cheap and come in a pack of 4. Has 12 holes in the nozzle (not sure what kind of an advantage that is) and most of all they are E85 compatible.

https://www.aliexpress.com/item/4-12holes-High-quality-performance-550cc-fuel-injector-for-G-M-C-FORD-chevrolet-replace-for/32720736959.html?spm=2114.01010208.3.18.y79sd4&ws_ ab_test=searchweb0_0,searchweb201602_5_10065_10068 _10000009_10084_10083_10080_10082_10081_10110_1011 1_10112_10060_10113_10114_10062_10056_10055_10054_ 10059_10099_10078_10079_10000012_10103_10073_10102 _10000015_10096_10000018_10052_10053_10107_10050_1 0106_10051,searchweb201603_9,afswitch_5,single_sor t_3_default&btsid=d375f673-52e7-4896-8a20-26a4082f8f37

[teoman]

On the canbus, by its nature it is a can bus and many devices can be connected to it, it is just a matter of piggybacking on to the cables.

[Harlan]

I run at 150psi, but that is well above the design pressure. A surflo style pump at ~60psi would be fine.

Yes the CAN bus can handle multiple devices, but OBD2 cannot. Most OBD2 devices send a request then take whatever returns with the correct address as the answer. This means if two different devices send OBD2 requests and only one goes through then both devices assume they got the answer for the question they asked.

This is not an issue with the CAN bus, or even OBD2 protocol (obd2 does give the PID of the request in the response). This is an issue with how most scanners implement OBD2, because they assume to be the only OBD2 device on the network.

If the information you need is already broadcast on the CAN bus then go for it. I get RPM this way. If you need any help let me know.

[teoman]

Thanks for the heads up on the OBD2. I do not have a scanner yet, wonder if the arduino is capable enough for serving both functions.

Also any idea of the different nozzle types on these injectors?

And how did you get the hose attached to the nozzle?

There are also these types of nozzles (or nozzle less?)
https://www.aliexpress.com/item/Top-feed-High-flow-performance-Standard-48mm-ev14-650cc-60lbs-E85-fuel-injector-High-impedance-Flow/32774687237.html?spm=2114.01010208.3.42.y79sd4&ws_ ab_test=searchweb0_0,searchweb201602_5_10065_10068 _10000009_10084_10083_10080_10082_10081_10110_1011 1_10112_10060_10113_10114_10062_10056_10055_10054_ 10059_10099_10078_10079_10000012_10103_10073_10102 _10000015_10096_10000018_10052_10053_10107_10050_1 0106_10051,searchweb201603_9,afswitch_5,single_sor t_3_default&btsid=d375f673-52e7-4896-8a20-26a4082f8f37

[Harlan]

The injector you have linked is fine. It looks identical to one of mine, but I haven't checked the part numbers. My 60# injector flows about 1000ml/min at 150#, I believe it was higher when new, but I don't have that figure.

As for different nozzles, the injectors have different spray patterns at different sizes, but I don't think that it is critical for this application. If you were using them for fuel then you would want the smallest injector to support your goals so you could get better atomization. It's not that critical when using it for water.

And for attaching the fuel injector I got an aluminum weld on bung from DIY auto tune. But there are other options available. My first attempt I had a single bung JB welded to my PVC intake and the injector lock wired in place. It wasn't pretty but it worked.

[teoman]

They say that you should only be injecting %20 of the fuel max.
At 1000ml/min, will be enough for 5000ml/min -> 300.000 ml/h. -> 300L /h

That is quite an amount of water!

Also how did you pulse the injector? Using the standard PWM function? If so did you lower the frequency?