Using Exhaust Water To Make More Horsepower!

Hello everyone and welcome. In this video we are talking about a water injection system that never runs out of water. So I have a couple other videos explaining how water injection systems work, why they're beneficial. If you're curious about that I'll include links in the video description. The short story is injecting water as it changes from a liquid to a gas within that intake manifold as it changes to that vapor you absorb some of the heat from the air around it so you cool down that intake charge you're able to operate more efficiently and you're able to make more power. Now the problem however is that this requires water. So by injecting water that means you need to have a tank on the core that has water in it and eventually that water is going to run out. So you've got a couple solutions here you can say hey customer you have to refill this water tank but customers are lazy they don't want to refill the water tank. Another solution you could perhaps collect rainwater but some people live in California so that's not an option for them. Another solution you could use the condensation that forms using the AC system but running the AC system isn't efficient and you don't want to be dependent on running that AC system in order to be able to operate the water injection system. So what are your other options? Well part of what's happening during combustion is you are taking a fuel you're adding to that oxygen you're burning that air and fuel and as a result you have combustion byproducts including CO2 and water and so exhaust gases are actually 8.5% water by weight about 13% water by volume. So that means you have a tremendous amount of water going out your exhaust that you could actually recover and reuse in your water injection system. So that's the idea behind an exhaust water recovery system. Now I found a study conducted by Teneco which was published in SAE and they were testing a 2 liter direct injection turbocharged engine and trying to see how viable of an option is exhaust water recovery. So looking at the overall system here you have your air intake your air comes in to the compressor side of the turbocharger it then passes through an intercooler it then passes through a water separator the water separator tries to collect water we'll talk about why this is right here a little bit later in the video then passes through your throttle into your intake manifold you've got this block right here where you have water sprayers injecting that water into the intake manifold before it enters into the cylinders of course that air and fuel then goes into the cylinders it's cooled by that water spray comes out the exhaust passes through the turbine of the turbocharger and then it's got three options as far as where that exhaust goes. So it can go through the three-way catalytic converter it can pass by this back pressure valve right here which they included in the experiment and then just straight out the exhaust or it can go through the catalytic converter and through a post catalytic converter valve and then back through the EGR cooler where it would then go back into the intake or they can actually have that air enter before going through the catalytic converter through the EGR cooler into a water separator through the EGR valve back into the intake. So that's the overall system as far as how that air is going to possibly circulate within this two liter turbocharged engine. Now we're not going to get into all that much detail of how these water separators work but in the study they tried using three different kinds of water separators and one important thing to note is that the locations are important because you have to have the temperatures of that air that's flowing into the water separator be near the dew point. The dew point meaning the temperature at which the water molecules will change from vapor and start to condense and so that condensation is what you will then collect and use and send to a tank which you can then inject that water into the engine. So there's three different types of separators they looked at. One was a passive cyclone separator essentially you're spinning around that air really quickly and then using that force the impact that centrifugal force against this cyclone separator to collect that water as it hits the walls using gravity to then pull it down collecting that water and they found that this one had the lowest pressure drop so that was one advantage of it meaning that the pressure you know of course has to pass through this device and so the greater the pressure drop the more power it requires to force you to go through it so the less efficient the engine is going to be. So you want a very low pressure drop you don't want to see this thing being super restrictive because that would mean the engine is less efficient. So they found the cyclone separator the passive cyclone separator had a low pressure drop they also tried using a passive membrane separator this uses capillary condensation essentially it's got these really fine pores in a membrane that help collect that condensation kind of similar to how a tree pulls water up through the trunk using capillary action and they found this passive membrane separator offered them the best quality water however it also had the worst performance meaning it collected the least amount of water and then they also used an active separator which was very similar to the passive cyclone separator except it was actually powered it required an electrical current to go to it to activate it. Now regardless of which separator is used they all have the exact same goal essentially they want to condense the water out of that air that's passing through it collect it and send it to a tank where it can be used with the water injection system and so you may be wondering you know what's going on with these locations why do we have one here after the EGR cooler why do we have one in the intake system meaning just plain old air that's going through is going to be passing through it and so it's interesting because remember you have to have these at a low temperature the air entering these water separators needs to be at a temperature low enough at which it can actually condense the water and collect it so while ideally you're going to have the most water just passing straight out the exhaust you can't actually collect that because it's far too hot you don't get anywhere near the dew point and as a result you can't pull any moisture out of the air there so you're not going to be collecting enough to actually put into a tank so you have to put it in areas where you've cooled that air so that's why this occurs after the EGR cooler it brings the temperatures down close to that dew point so it can start condensing that water and then pulling water out of the air and sending it to this water tank now you're wondering wait a minute why do we have one in the intake and I found this fascinating as well so part of it is you know when you're injecting uh if you have air going into an engine that has a very high humidity this isn't a good thing so that water that's in that air is actually taking up space that could otherwise be oxygen or fuel so you don't want to have high humidity air going into an engine and so what's happening here is this water separator is trying to pull that air that water out of the air so you just have this dry air going in right here but then you're thinking wait a minute then you're just spraying water right back into it well the effect of cooling the air which is done by injecting a liquid water remember this is collecting uh it's trying to take water vapor and turn it into a liquid this is injecting liquid that is then turning into a vapor and by turning it into a vapor it actually offsets that effect of increasing the humidity of the air and so by cooling that temperature enough you get those benefits of more power greater efficiency so there actually is a very logical reason for having this in the intake you can take advantage kind of two ways you're pulling moisture out which is going to help you and then you're going to use that water again through your water injection system okay so what's the best location to put these water separators and where do you get the cleanest water to use in your engine and so as we mentioned previously the passive membrane separator although it had the worst performance it had the cleanest water that it drew out from the air and then as you might imagine as far as the different locations of where you're pulling water from the water separator after the intercooler pulled out the cleanest water and then this one was not quite as clean as using the water separator after the intercooler so after using you know the exhaust to actually recover water from the water is not quite as clean and then actually what they found is that the water as you might imagine coming from after passing through the catalytic converter was cleaner than if they were to take it from before the catalytic converter so ideally you're taking water using a passive membrane separator using after the charge air intercooler because that's where you get the cleanest water unfortunately that's not the best performance so you're kind of balancing between different aspects as far as which water separator do i want to use and what locations am i using it from because you get a lot of water coming through the exhaust so it's a good place to pull from now let's get into the effects on ignition timing on air fuel ratios and on brake thermal efficiency of using this water injection system so they were looking at data on this two liter turbocharged engine and when operating at full load meaning 100% throttle what they found so that we're looking at varying the water to fuel ratio so a ratio of how much water is injected to how much fuel is injected by mass so zero meaning you're injecting no water whatsoever 50% meaning take however much fuel you're injecting you're injecting half that much in water into that intake manifold and so what they found is at full load they could advance the timing a further 20 degrees when they were at 50% water to fuel water injection so a significant amount of timing advance they also found that they could lean out not lean but a less rich mixture could be used if they were using a 50% water to fuel ratio so where it was operating at a 12 to 1 air to fuel ratio with full throttle they can bring that as high as 13.5 to 1 with the water injection system still operate safely and still operate with cool temperatures so it's doing this 12 to 1 to operate safely keep the temperatures down it doesn't have to do that as much when you're using the water injection system so you raise that air fuel ratio up to 13.5 to 1 the result is you increase your brake thermal efficiency so by advancing the timing and by increasing your air fuel ratio you're able to improve that thermal efficiency from 26% up four full percentage points to 30% meaning about 15% more efficient by using this water injection system super cool now what are the effects of water injection on nitrogen oxide emissions so one of the reasons companies are actually looking at using water injection is to improve the emissions of their vehicles and so one of the interesting things about this is in this study they looked at this you know the nitrogen oxide emissions at different loads so they were looking at full load this scenario we have right here and what they noticed which is pretty bizarre to see is that the nitrogen oxide emissions actually increase as you start to inject more water so why would the nitrogen oxide emissions increase by injecting water if we know that injecting water means that you will have less nitrogen oxide emissions well the reason is there's something else that's changing here so remember we're going from an air fuel ratio of 12 to 1 to 13.5 to 1 and the closer we get to stoichiometric air fuel ratios the greater nitrogen oxide emissions we have and so that's why you actually see this this air fuel ratio effect is actually overpowering the effect of injecting the water now if you then go to a high load meaning not full load a high load so you would be operating at about the ideal air fuel ratio about 14.7 to 1 what you see is that without injecting any water of course you have quite a bit of nitrogen oxide emissions when you operate at the ideal air fuel ratio nitrogen oxide emissions are basically at their peak then by injecting water your air fuel ratio is going to remain constant here at this high load it's going to remain at that 14.7 to 1 but by injecting water you're cooling the temperatures within that cylinder and so as a result you do see that water itself does actually decrease the nitrogen oxide emissions now it's still higher at this high load than at full load because the full load is operating at such a cooler condition but it's very interesting to see that that fuel enrichment process the richer the air fuel ratio that will overpower the effect of injecting water as far as it's concerned with nitrogen oxide at this high load you're not doing that so you see a decrease the more you inject water the less nitrogen oxide emissions you have all right so the big question can the system actually sustain itself so what you need to happen here is for the potential amount of water that could be collected to be greater than the amount of water that you're actually injecting so if you have excess that's no problem there are solutions for it you could have a bypass around your water separator you could send more just straight out the exhaust rather than rerouting it there are ways to deal with excess water but if you're not getting enough water versus how much you're injecting then you have a problem and so in this study they looked at the separator inlet temperature coming into these water separators versus the collection efficiency of the devices that they were using and so they kind of were able to map out you know what operating conditions of the engine would actually allow for this system to just be completely sustainable or would always be producing enough water and so if they were able to keep the temperature before entering the EGR water separator after coming through the exhaust gas recirculation system if they were to keep that at 45 degrees or less celsius then they could sustainably run it and with the charge air separator if they were able to keep those temperatures below 25 degrees celsius then they could make this system work as you start to get into these hotter regions and the temperatures increase so here's kind of the divide here where you've got that one-to-one the amount of water that you're collecting is equal to the amount of water that you're injecting so anything on this side works anything on this side long term does not work so in scenarios where you're have a high average operating condition so a cycle of driving that the average is very high for example driving on a track this probably isn't going to be able to sustain that because the exhaust temperatures are too high it's not going to be able to recover enough water for what you're asking it for but in lower load scenarios which honestly is more relevant to road driving they did find that they were actually capable of collecting enough water that it could actually continuously run so quite a cool system in that there actually are operating conditions and cycles in which the amount of water you are collecting could be greater than the amount of water that you're injecting thus you can run it indefinitely very neat system if you guys have any questions or comments of course feel free to leave those below thanks for watching