New Injection Point Idea
07-27-09, 04:08 AM
#1
New Injection Point Idea
First off if you are still using the Oil Metering Pump, this will not work for your setup
Anyways... I have been working on designing a water injection system that will work for my car the best. I have most of the system items planned out, but I was still working on Injection points, and came up with a super cool idea.
Why not injecting some of the water right into the motor, thru the oil metering points in the rotor housing. The hole thru the rotor housing is about 1/16-1/8, after removing the orifice that is inside the point you would have this hole to do your bidding.
The only problem i see with using this port to inject the water directly into the motor is a good way to atomize the water/aly, unless you us a high pressure (90+) you would have big drops left inside the motor, what is your idea on that? Also what about the added pressure (Once the intake ports close) on the flow, I figured I would have to install a one way valve on both feeds. Also lets say you have 16psi of boost inside the motor after the intake valves have closed you are just starting to compress this area, I have no clue what this pressure would be before the apex seal moves over the oil injection port. Lets say it is 80psi and you are injection at 100psi, would this increase the cylinder pressure higher then you would think it would be, like after the water got in there would it be equal to injecting 17psi of boost (By the displacement of water inside)
The above would really be the second point of injection, I am just trying new ideas really, My other point would be just downstream from my BOV (after intercooler) this way when the BOV opened I would not have any water/aly sprayed into my engine compartment.
Ok that is my hair brained idea, what do you think.
Pro's
Con's
Thanks in advance
Anyways... I have been working on designing a water injection system that will work for my car the best. I have most of the system items planned out, but I was still working on Injection points, and came up with a super cool idea.
Why not injecting some of the water right into the motor, thru the oil metering points in the rotor housing. The hole thru the rotor housing is about 1/16-1/8, after removing the orifice that is inside the point you would have this hole to do your bidding.
The only problem i see with using this port to inject the water directly into the motor is a good way to atomize the water/aly, unless you us a high pressure (90+) you would have big drops left inside the motor, what is your idea on that? Also what about the added pressure (Once the intake ports close) on the flow, I figured I would have to install a one way valve on both feeds. Also lets say you have 16psi of boost inside the motor after the intake valves have closed you are just starting to compress this area, I have no clue what this pressure would be before the apex seal moves over the oil injection port. Lets say it is 80psi and you are injection at 100psi, would this increase the cylinder pressure higher then you would think it would be, like after the water got in there would it be equal to injecting 17psi of boost (By the displacement of water inside)
The above would really be the second point of injection, I am just trying new ideas really, My other point would be just downstream from my BOV (after intercooler) this way when the BOV opened I would not have any water/aly sprayed into my engine compartment.
Ok that is my hair brained idea, what do you think.
Pro's
Con's
Thanks in advance
Last edited by Rx7_Nut13B; 07-27-09 at 04:16 AM.
07-29-09, 06:57 PM
#4
Racing Rotary Since 1983
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an interesting idea that might be quite complex.
as you know the hole is to lube the apex seal which contacts the hole. it is important that a bit of oil be on the apex seal either from the EOP or by using premix. perhaps the water might clean the oil away which could lead to apex seal failure. perhaps not.
maybe thermal shock. maybe not.
maybe the chamber pressure might be too much to overcome... at times the rotor is at BDC, other times, just before the hole is closed, pressure is rising.
probably the reason you didn't get much as to responses is most people just don't have an answer. it is great to see new ideas and if you give it a try we will all be interested.
good luck,
howard
as you know the hole is to lube the apex seal which contacts the hole. it is important that a bit of oil be on the apex seal either from the EOP or by using premix. perhaps the water might clean the oil away which could lead to apex seal failure. perhaps not.
maybe thermal shock. maybe not.
maybe the chamber pressure might be too much to overcome... at times the rotor is at BDC, other times, just before the hole is closed, pressure is rising.
probably the reason you didn't get much as to responses is most people just don't have an answer. it is great to see new ideas and if you give it a try we will all be interested.
good luck,
howard
07-29-09, 10:12 PM
#5
Thanks Howard,
Just looking for things that I havent thought about, I did think about the lube, and the pressure inside the housing.
A Engineering friend at work, that is a big corvertt guy, talked about this idea today. I told him some of my consurns. We do a lot of water injection on are Gas Turbines at work, and the proof that water injection helps is the Mega Watt increase that we get during the hot part of the day. One of are Gas Turbines at Max Load will be about 77 MW's then when the water injection turns on it will increase to approx 80MW's. Intake Temps today went from 88F to 81F, also discharge pressure went up from 144psi to 149psi. Just some food for thought...
My Question is in Black and his reponce is in Red
1)water not atomizing correctly thru the 1/16in hole
If you put enough water pressure anything will atomize in any pressure, about a 100psi difference would be great
2)Pressure to high for the water to get into the housing
The Max pressure inside the rotor housing should be a little above 300psi with boost (He didn't calculate it right then, this is from awhile back when we did the calculations with a Xpsi amount of boost that I forgot) Then have 250psi Water injection pumps, this will be plenty of water pressure he says
3)The water coming into the rotor housing will cause the Air/Fuel mix to be moved to the other side, or displaced by the entering water.
With the water coming in that fast at a much higher pressure will create a very turbulent A/F mixture, you would be making sure the mix is uniformed better then when it was just the Air/Fuel coming into the rotor housing.
4)What to do about the pressure difference between the two rotor housing while injecting water.
You can install a check valve or just allow the water to go to the lower pressure side first then go to the other rotor, back and forth
I really like the ideas that he was coming up with, it sound promising. We did talk about the water cleaning the apex seal groves as it passing the seal, but you would have to go really high pressure to hurt the seal like a pressure washer psi 3000+psi
I will be going thru with this project so I will try and get some inside on how it works, but this will be a few months.
Just looking for things that I havent thought about, I did think about the lube, and the pressure inside the housing.
A Engineering friend at work, that is a big corvertt guy, talked about this idea today. I told him some of my consurns. We do a lot of water injection on are Gas Turbines at work, and the proof that water injection helps is the Mega Watt increase that we get during the hot part of the day. One of are Gas Turbines at Max Load will be about 77 MW's then when the water injection turns on it will increase to approx 80MW's. Intake Temps today went from 88F to 81F, also discharge pressure went up from 144psi to 149psi. Just some food for thought...
My Question is in Black and his reponce is in Red
1)water not atomizing correctly thru the 1/16in hole
If you put enough water pressure anything will atomize in any pressure, about a 100psi difference would be great
2)Pressure to high for the water to get into the housing
The Max pressure inside the rotor housing should be a little above 300psi with boost (He didn't calculate it right then, this is from awhile back when we did the calculations with a Xpsi amount of boost that I forgot) Then have 250psi Water injection pumps, this will be plenty of water pressure he says
3)The water coming into the rotor housing will cause the Air/Fuel mix to be moved to the other side, or displaced by the entering water.
With the water coming in that fast at a much higher pressure will create a very turbulent A/F mixture, you would be making sure the mix is uniformed better then when it was just the Air/Fuel coming into the rotor housing.
4)What to do about the pressure difference between the two rotor housing while injecting water.
You can install a check valve or just allow the water to go to the lower pressure side first then go to the other rotor, back and forth
I really like the ideas that he was coming up with, it sound promising. We did talk about the water cleaning the apex seal groves as it passing the seal, but you would have to go really high pressure to hurt the seal like a pressure washer psi 3000+psi
I will be going thru with this project so I will try and get some inside on how it works, but this will be a few months.
Last edited by Rx7_Nut13B; 07-29-09 at 10:16 PM.
07-30-09, 08:10 PM
#7
another thing that would worry me is you would be getting a false AIT reading. this is why you are supposed to inject before the AIT. at least 6 inches also.
but other than that, i had the same idea but injecting pure meth. not for cooling but for added fuel. takes the spot of adding bigger injectors and dual fuel pumps. cheaper and easier, with more power!
but other than that, i had the same idea but injecting pure meth. not for cooling but for added fuel. takes the spot of adding bigger injectors and dual fuel pumps. cheaper and easier, with more power!
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07-31-09, 04:19 AM
#8
I agree that you will not see the entire Temp drop, but there will be a third injection point right before the TB, and my air temp is right before that.
I wanted the extra water in the rotor housing, right where most detonations happen, the water will be spraying into the housing none stop all most to the point of TDC.
I wanted the extra water in the rotor housing, right where most detonations happen, the water will be spraying into the housing none stop all most to the point of TDC.
08-01-09, 05:35 AM
#9
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Don't bother trying to inject straight into the rotor housing, it's more trouble then it's worth. You'd basically be trying to convert to direct injection. Most direct injection motors run 1500psi of fuel pressure.
Use the omp ports in the manifold. It's a good location and will prevent all of the headaches associated with trying t inject straight into the motor. Also don't both injecting before the TB or the AIT sensor. Injecting too far upstream leads to the mixture falling out of suspension and causes puddling. The injection does drop you charge temps a bit, but the main cooling effect is from it hitting the hot rotor and flashing to steam ..... this state change is what absorbs the thermal energy and prevents detonation, well besides the higher octane of the mixture.
Use the omp ports in the manifold. It's a good location and will prevent all of the headaches associated with trying t inject straight into the motor. Also don't both injecting before the TB or the AIT sensor. Injecting too far upstream leads to the mixture falling out of suspension and causes puddling. The injection does drop you charge temps a bit, but the main cooling effect is from it hitting the hot rotor and flashing to steam ..... this state change is what absorbs the thermal energy and prevents detonation, well besides the higher octane of the mixture.
08-01-09, 10:15 AM
#10
Don't bother trying to inject straight into the rotor housing, it's more trouble then it's worth. You'd basically be trying to convert to direct injection. Most direct injection motors run 1500psi of fuel pressure.
Use the omp ports in the manifold. It's a good location and will prevent all of the headaches associated with trying t inject straight into the motor. Also don't both injecting before the TB or the AIT sensor. Injecting too far upstream leads to the mixture falling out of suspension and causes puddling. The injection does drop you charge temps a bit, but the main cooling effect is from it hitting the hot rotor and flashing to steam ..... this state change is what absorbs the thermal energy and prevents detonation, well besides the higher octane of the mixture.
Use the omp ports in the manifold. It's a good location and will prevent all of the headaches associated with trying t inject straight into the motor. Also don't both injecting before the TB or the AIT sensor. Injecting too far upstream leads to the mixture falling out of suspension and causes puddling. The injection does drop you charge temps a bit, but the main cooling effect is from it hitting the hot rotor and flashing to steam ..... this state change is what absorbs the thermal energy and prevents detonation, well besides the higher octane of the mixture.
You have some small points but you are kinda off.
On a DI engine the fuel is being injected right before TDC about 1-2in's before the piston is @ TDC. At this point the cylinder pressure is above 250-300psi. Then when it fires off it can become as high as 2500psi. The reason why they use such a high pressure to inject the fuel is the same reason why we have rising rate fuel pressure regulators, to get the proper amount of fuel into the cylinder.
Now in a rotor where I am trying to inject at the pressure will be low (Boost pressure) when the intake just opens, and somewhere near 100psi because the rotor isn't near TDC when the Oil metering port closes.
This is the reason why if you use some of the High pressure pumps on the market (250psi) you will not have a issue with getting a fine mist inside the rotor housing before the mixture is at TDC, and as everyone know this is ground zero where detonation happens. Even if the water injected doesn't totally change states when the injection stops, the heat build up near TDC will make sure the water left will flash off.
I only have 2 OMP Injection ports because my car is a FD, so I cant inject that that point.
The number one reason why the mixture falls outs, as you say, is because of low pressure at the injection point (I.E. Not having a good spray pattern) or Injecting at a low air flow. Turning the Water Injection on when there is not enough flow inside the intake, this can happen at low RPM's or Very Low boost.
08-01-09, 02:09 PM
#11
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Sorry I was generalizing a fair bit.
This means you need a check valve in the port capable of taking the combustion pressures, as well as a pulse width modulated injection controller. Although if you have a stand alone that can do staged injection you can use the second table for your water injection. The check valve/nozzle also needs to have a higher then normal cracking pressure to prevent leaking while the engine creates vacuum.
This is true, but better atomization means more surface area, and more heat extracted from the combustion process. which is why most good WI systems use pumps that are rated for 100-150psi.
I wasn't aware of this. Any chance you have a link the the S6/S7 fsm diagram of the omp system?
This I have to disagree with, to a degree. The longer the path the droplets have to travel combined with the number of obstacles and twists all platy into the droplets falling out of suspension. It is much more likely at low velocities, but even at high velocity's things like the throttle plate will still cause puddling as the droplets collide with it.
All that being said. What you want to do can be done, and chances are with off the shelf parts. It's just a lot more headache then your typical WI set up.
The number one reason why the mixture falls outs, as you say, is because of low pressure at the injection point (I.E. Not having a good spray pattern) or Injecting at a low air flow. Turning the Water Injection on when there is not enough flow inside the intake, this can happen at low RPM's or Very Low boost.
All that being said. What you want to do can be done, and chances are with off the shelf parts. It's just a lot more headache then your typical WI set up.
08-01-09, 04:38 PM
#12
Sorry I was generalizing a fair bit.
This means you need a check valve in the port capable of taking the combustion pressures, as well as a pulse width modulated injection controller. Although if you have a stand alone that can do staged injection you can use the second table for your water injection. The check valve/nozzle also needs to have a higher then normal cracking pressure to prevent leaking while the engine creates vacuum.
Well i thought about a few ways to deal with the injection and one way valves if i was going to use them. I am planning on using two solenoid valves for the two injection points (1 housing(s) / 1 Pre Throttle Body). These solenoid valves are rated @ 500psi / 25 in/hg but are not a quick on/off/on like some that I have seen for variable injection systems. On my HBP motor my vacuum is low most of the time except during engine deceleration. My main problem is the difference in pressures between the two rotor housing, one will be on the high side and the other will be low. I figured that the water would choose the lower pressure then swap back and forth.
On the Staged injection, another idea that I had before this current one was to use a Peak and Hold injector driver to run multiple normal fuel injector converted to water injection, this way you would you would only need one fuel injector input per rotor and control multiple water injectors with it. Also after you correctly sized the WI for the normal 15-20% water injection to fuel flow, you could use your fuel map that controls normal fuel delivery to control the water injection also.
This is true, but better atomization means more surface area, and more heat extracted from the combustion process. which is why most good WI systems use pumps that are rated for 100-150psi.
I agree, I am going to be using a 250psi none pulse pump
I wasn't aware of this. Any chance you have a link the the S6/S7 fsm diagram of the omp system?
I will work on getting you one asap
All that being said. What you want to do can be done, and chances are with off the shelf parts. It's just a lot more headache then your typical WI set up.
This means you need a check valve in the port capable of taking the combustion pressures, as well as a pulse width modulated injection controller. Although if you have a stand alone that can do staged injection you can use the second table for your water injection. The check valve/nozzle also needs to have a higher then normal cracking pressure to prevent leaking while the engine creates vacuum.
Well i thought about a few ways to deal with the injection and one way valves if i was going to use them. I am planning on using two solenoid valves for the two injection points (1 housing(s) / 1 Pre Throttle Body). These solenoid valves are rated @ 500psi / 25 in/hg but are not a quick on/off/on like some that I have seen for variable injection systems. On my HBP motor my vacuum is low most of the time except during engine deceleration. My main problem is the difference in pressures between the two rotor housing, one will be on the high side and the other will be low. I figured that the water would choose the lower pressure then swap back and forth.
On the Staged injection, another idea that I had before this current one was to use a Peak and Hold injector driver to run multiple normal fuel injector converted to water injection, this way you would you would only need one fuel injector input per rotor and control multiple water injectors with it. Also after you correctly sized the WI for the normal 15-20% water injection to fuel flow, you could use your fuel map that controls normal fuel delivery to control the water injection also.
This is true, but better atomization means more surface area, and more heat extracted from the combustion process. which is why most good WI systems use pumps that are rated for 100-150psi.
I agree, I am going to be using a 250psi none pulse pump
I wasn't aware of this. Any chance you have a link the the S6/S7 fsm diagram of the omp system?
I will work on getting you one asap
All that being said. What you want to do can be done, and chances are with off the shelf parts. It's just a lot more headache then your typical WI set up.
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