Water/alcohol injection and diesel engines

[tillyfromparadise Senior Member Find all posts View Profile Close tillyfromparadise]

Re: Water/alcohol injection and diesel engines

Spraying water on the intercooler is probably a lot safer that spraying it into the air intake

[Emporator Member Find all posts View Profile Close Emporator]

Re: Water/alcohol injection and diesel engines

Spraying water on the intercooler is probably a lot safer that spraying it into the air intake

You could do both for extra gains!

[Emporator Member Find all posts View Profile Close Emporator]

Re: Water/alcohol injection and diesel engines

Hello all!

Looks like this topic has really begun to gather some interest! Excellent to hear that a few of you out there have experienced some benefit from water injection!

I was thinking last night that since water cooled down the incoming air, then cooler water would drop the temperature even further, right? Trouble is, water freezes a 0 degrees celsius! Not a problem however if you've mixed an alcohol in with said water!

Wanting to start out with the coldest possible mix of water and alcohol, I made some room in our deep freezer for the 20 litre plastic drum I intend to use (a mix of water, ethanol and methanol). I checked the temperature this morning - it's around -20 degrees in there and the mix hasn't frozen! So I figure that since I've lowered the temperature of the mix by about 40 degrees celsius I should see some additional benefits! I'll have to do trials of course of room temperature water/alcohol versus the freezing cold stuff.

[geewizztoo Senior Member Find all posts View Profile Close geewizztoo]

Re: Water/alcohol injection and diesel engines

Hi Tom,

I'm not sure it's worth the extra trouble to cool the water/alcohol and may even be detrimental, here's my thoughts. Evaporative cooling takes advantage of the large amount of energy required to make a phase change, in this case liquid to vapour. See attached graph for water.

The plateau at 'B' is the ice/water phase change and the plateau at 'D' is the water to steam phase change. As you can see the energy absorbed over the 'D' plateau is very large in comparison to the energy absorbed during the heat up ramp 'C'. 2260 J/g compared to 420 J/g for the whole of the 0-100C range.

What is of most importance is to get ALL of the water droplets to completely vaporise before entering the cylinders. This is where the greatest amount of energy is absorbed from the air. By cooling the liquid you may in fact retard the vaporisation process and it might be more beneficial to heat the fluid to accelerate vaporisation.

Cheers,

Wayne

[Emporator Member Find all posts View Profile Close Emporator]

Re: Water/alcohol injection and diesel engines

Hi Wayne!

I'd never actually thought about that - I can see where you're coming from though. I'll try both cold and warm water/alcohol mixtures to see how I go. There's bound to be a happy medium in there somewhere! So you think that warm water/alcohol might be a better fluid to inject?

I've just been fiddling with the water injection system over the kitchen sink - the water droplets are so small it's more like a superfine mist than anything else. I'm getting excited about fitting it to the Pug - I feel like it's Christmas again!

[tillyfromparadise Senior Member Find all posts View Profile Close tillyfromparadise]

Re: Water/alcohol injection and diesel engines

Hello David,
No, I have no experience with water injection.
Water is not a fuel and does not burn.

I have googled Water injection in diesels and by and large about the only thing water seems to do in Diesels is improve some types of emissions.
Excess water can also do harm if it gets into the sump.

I would think that if water injection does provided significant improvement in anything other than emissions every diesel truck in Australia would have water injection installed on their Engines from the factory. I do not believe this is the case.

Of course fumigating with methanol will provide extra power because methanol is a fuel and has a Stoichimetric ratio that is condusive to increased power at the expense of increased methanol consumption. Methanol also costs about $1.30 a litre the last time I checked.

I too await the results to some well thought out tests containing meaningful numbers

[Guest Close David]

Re: Water/alcohol injection and diesel engines

Thanks for your feedback Tilly.
Your point with trucks is well taken however they are running the fuel the engines were designed for, not something different like we are doing with Veg fuels.
My main fear with running unheated blended WVO as fuel was the build up of deposits in the combustion chamber which would have poor concequences in relation to the injectors and ring coking.

Do you have any thoughts as to the effectiveness of water in removing and preventing these buildups?

[Emporator Member Find all posts View Profile Close Emporator]

Re: Water/alcohol injection and diesel engines

David,

Even though I'm only young and have never tried water injection, I've got a funny feeling that water injection would be excellent for removing the deposits from SVO/WVO use. Call it a gut feeling (or is that hunger striking again?) but I think that it'd be great for such an application. I guess we'll have to wait until someone with a straight oil conversion tries it out.

Any volunteers?

[Terry Syd Senior Member Find all posts View Profile Close Terry Syd]

Re: Water/alcohol injection and diesel engines

My impressions are that it may remove carbon deposits in the combustion chamber and ports, however I don't think it will help in regards to ring sticking.

In trying to understand how the carbon in the combustion chamber may be cleaned out, I theorise that the hard carbon probably gets small fractures from the quick cooling of the water droplets. These small fractures lead to larger fractures with the continued heating and cooling. Eventually, the entire deposit is chipped away - kind of like the weathering of rocks.

However, the rings exist in a far different environment. It is the 'scrubbing' of the moving ring that helps keep the ring groove clean. I would prefer to have a good quality oil, that was high in detergents, helping to dissolve any deposits in a ring groove rather than some water. Water is a lousy lubricant. It also promotes rust.

Whereas I would be willing to experiment with an occasional watering down of the engine to remove built up carbon (assuming that this actually occurs), I would be reluctant to continue to pump water into the cylinder all the time. The rings in the cylinder wear fast enough without the thin film of lubricant on the cylinder wall being compromised with water.

The water injection systems I have run into are for dampening the effects of detonation in petrol engines, something that occurs primarily at full throttle, in other words a transient phenomena, not something that needs continuous attention. Given the destructive effects of detonation, a bit of water in the cylinder to dampen the detonation is a far better alternative.

I too look forward to more research on this topic.

[Guest Close David]

Re: Water/alcohol injection and diesel engines

After waiting most of the week to have a go at validating my seat of the pants impression of the improvement my rough and ready water injection system had made to Helga, today I was able to find some deserted road at a local industrial area to run some numbers.

I made 3 runs each way along the test road. Fuel used was my usual blend of 20% unleaded, 80% WVO. All tests were run back to back without switching off the engine with an untimed run both ways in between changing water/methanol mixes to clear the pump and lines of any residual mix from the past test and stabilize engine temp which stayed very constant throughout the test.

An interesting observation was the impressive (excessive?) amount of fuel used. In the drive to the test road, the testing runs and the drive home totaling slightly less than 15Km, Helga consumed approx. 4.5L of fuel, 3.3Km/L ! I wonder what the average fuel consumption for the test runs themselves were... 2km/L ??

3 runs each way were made along the test road from the same start point at each end of the road. The runs were from a standing start to 60 Km/h with the auto in drive and the accelerator held flat to the floor so as to keep the kickdown active right through the runs which also activates the water injection pump.
I was hoping to do 80 Km/h runs but this was cutting things a bit fine for braking on the road I was using and after repeated tests to 60, the brakes were starting to get very hot just from that speed. Some other tests showed better times by holding the gears in low range but this was really revving the engine out and for the sake of more real world driving and testing error reduction, the gearbox was left in “D”.

On the times shown, the fastest and slowest run on each test were disregarded and the remaining four times were averaged.
The greatest variance in times was with water only. Two runs were done with W0 being the first and the last set of runs done. This was to see what if any difference factors such as engine and gearbox heating may have created as well as weather factors. Similar variations in times were noted on both tests however the average run times differed by just a fraction over 1/10th of a second. Well within testing error and showing that the tests were very consistent and with a minimum of variables.

The tests were run in the order listed below. First 100% Water (W100) then a 50-50 water / meth mix (M50), 75% meth (M75) then no water (W0) and finally a second test of water only. The amount of liquid injected on all tests was the same and nothing other than emptying the remaining fluid from the previous test and refilling the supply bottle was done. The rate of liquid flow into the engine was approx 330 CC per minute.
A test with 100% Methanol was abandoned due to the pronounced “Rattling” noise the engine produced in the tests when running M75.

0-60Km/h average times.
W100 9.75 sec
M50 7.83
M75 7.46
W0 10.17
W100#2 9.63

While the margins here may be relatively small, it should be kept in mind that these differences were relatively slow and short runs to 60 Km/h only instead of the more standard 0-100 test.

The difference from the slowest average time of 10.17 with no water compared to the fastest average of 7.46 with M75 is a huge difference in itself (2.71 sec) and would be even more significant in a 0-100 test. (Anyone know how to work out the Percentage improvement?)

I believe based on these short run tests, a traditional run to 100Km/h would show far greater differences and benefits between the different test and mix times. It is also likely that these results could be improved upon by testing the optimum amount of liquid to be injected and using a higher quality spray nozzle which produces a finer and more easily evaporated mist into the engine.

What these tests don’t show but is highly significant is the difference in the “drivability” of the car and the difference it makes in responsiveness in everyday driving. Helga is now able to eat late model Turbo Diesel Patrols for breakfast even carrying the whole family and a boot full of WVO .

In a car like the 300D, this can only make the car safer in today’s traffic conditions.

Detail Shot of Highly Sophisticated Injection Nozzle and custom Bracket.

The Autobahn Burner Poised for another assult on breaking the world land speed record of 1854

[Terry Syd Senior Member Find all posts View Profile Close Terry Syd]

Re: Water/alcohol injection and diesel engines

The W50 run seems the most reliable, no use damaging an engine with detonation. Based upon the reduction in time of acceleration from no water to a W50 mix, that is a 23% reduction in elapsed time.

If you showed up at a drag strip and made that kind of improvement, everyone and their dog would be hanging around your pit trying to figure out what you were running.

Well done.

[tillyfromparadise Senior Member Find all posts View Profile Close tillyfromparadise]

Re: Water/alcohol injection and diesel engines

Interesting numbers

The increase in power with the 50/50 mix was not "Free"
It is achieved by using the equivelent of 9 litres an hour of methanol extra added to the Fuel you would normally use.
I think you would probably achieve similar results if you used methylated spirits (ethanol) instead of methanol. So the choice would probably be which is the cheapest.
At the expense of added cost for the fuel, you have saved yourself the expense of installing an LPG system if all you are after is added power when you put your "Foot to the floor"

It would be interesting to see what happens if you used biodiesel instead of 80% WVO/20% ULP in the test.

[Guest Close David]

Re: Water/alcohol injection and diesel engines

Interesting numbers

The increase in power with the 50/50 mix was not "Free"
It is achieved by using the equivelent of 9 litres an hour of methanol extra added to the Fuel you would normally use.
I think you would probably achieve similar results if you used methylated spirits (ethanol) instead of methanol. So the choice would probably be which is the cheapest.

I totally agree Tilly. The performance boost comes at a price much the same as people who use nitrous Oxide have to pay for their laughing gas.
I had also wondered about using methylated spirits but I have my doubts if I could purchase metho at the $1.30-.40 that methanol can be bought for.

I'm not sure that anyone would ever run a car flat out for an hour straight but even if they did, the cost of the meth would likely not be much if any more than running a petrol car for an hour if a person was running WVO or bio as their fuel. I had thought of running a 50% mix if I were going to tow a trailer full of equipment to one of my country jobs but I still see the meth as being more of a boost for going up hills etc. rather than something the engine would be injesting constantly. I think the extra fuel cost may be well worth the added boost in this case.

At the expense of added cost for the fuel, you have saved yourself the expense of installing an LPG system if all you are after is added power when you put your "Foot to the floor"

My prime motivation for trying the water injection was as a way of preventing the possibility of buildup in my engine such as coking of the injectors and rings. The meth mix is just something the petrol guys do and my initial test with it was just out of curiosity. I was surprised to feel the extra kick I did and then just wanted to verify it wasn't my imagination.

If I were interested in outright performance and was going to run an alchol blend constantly I would certainly see if I could get metho cheaper than the Methanol.

Some years ago I experimented with running a 2-stroke petrol engine on unheated WVO and learnt how quickly veg oils can carbon up an engine if they are not used in the right way. I am now thinking I may drag out one of the many small engines I have up the back and run it on veg oil again to fill it full of carbon and then strip it down, photograph it, rebuild it and run it again with the water injection to see how well it cleans the engine and if the water can free up rings that are stuck with carbon as happend last time.

Another test could be to run a clean engine on oil with water from the start and see if it prevented any carbon buildup.
The biggest hurdle I see in this test is setting up a water spray minimal enough so it won't put the fire out in a small petrol engine that is struggling to run on WVO. A good amount of regular engine oil mixed with petrol in a 2-Stroke soon carbons everything up so maybe this would work sufficently for my test.
I have plenty of parts to rebuild these engines if nessacary which dosen't take long but the time in setting up these tests and doing them will be the obstacle but I'll see what I can do over the next few weeks.

It would be interesting to see what happens if you used biodiesel instead of 80% WVO/20% ULP in the test.

I thought about doing the test on Bio but I then figured the fuel wouldn't matter as long as it was the same for all the tests as I was testing the difference the water injection made rather than the performance of the fuel. I did have a kero blend in the car I was testing but as I normally use unleaded and am likely to continue doing so, I decided to standardise the numbers based on my normal blend.
I would imagine that the water would have similar effects on all fuels.

Are you thinking that the water may affect Bio differently or were thinking more of a comparison of times between the fuels? I could always standardise a 50% meth mix and change the fuels. Would be good try bio, unleaded blend, kero blend and diesel to see the differences.

I was also wondering how a mix of Bio and water would go as an injection mix if it were possible to dissolve the bio in the water with some metho to get them to mix.

[tillyfromparadise Senior Member Find all posts View Profile Close tillyfromparadise]

Re: Water/alcohol injection and diesel engines

Hello David

Your test showed a 4%- 5% increase in power using 100% water.

The reason it would be interesting to see what happens using biodiesel instead of WVO/ULP is that biodiesel and WVO/ULP have substantially different viscosities. It would be interesting to see if this increas in power is still achieved if you use a fuel closer in viscosity to what the injection system is designed for.
The injection system in most diesel engines is designed for a fuel with a lower viscosity than biodiesel so the WVO/ULP mix is very high in viscosity compared to what the injection system was designed to use.
Most people on this forum seem to use biodiesel, not a WVO ULP mix.
If anything, biodiesel seems to generate less carbon than normal diesel so if all the water injection does is clean out carbon (Maybe) but does not give appreciably more power when used with biodiesel then that is handy to know too.
Also, many of these injection pumps are apparently not set to deliver as much fuel as the engine can handle. There is a simple adjustment in the back of the Bosh inline fuel pumps.
SsangYong Mussos which use the Bosh inline Pump can typically achieve another 20 HP by adjusting the IP, a 15% increase in power

There is no doubt that fumigating alcohol into the engine will give increased power.
The alcohol goes in as a spray, not a gas so does not displace as a large a volume of air as LPG does.
Methanol has a stoichiometric ratio of around 6.4:1 instead of the 14.6:1 that diesel has. Ethanol is around 9:1 so you should be able to achieve a "Bigger Bang" with either alcohol.

[tillyfromparadise Senior Member Find all posts View Profile Close tillyfromparadise]

Re: Water/alcohol injection and diesel engines

Hello David

Read this discussion thread. The Musso 2.9 diesel is a license copy of the 5 cylinder Mercedes Diesel you have Board Message

I know a fellow who first installed a larger through flow exhaust said the dyno showed a 20 HP improvement to 140 HP. He then made the adjustment in IP and also adjusted the turbo for quicker response.
I believe he now has to drive with his foot constantly on the brake.