Diesel water emulsification

[Isaac Zackary]

I have a 1985 VW Golf non-turbo diesel that I'd love to turn into a pusher trailer for my 2013 Nissan Leaf. On the one hand it's a perfect candidate, economically speaking, since it's very fuel efficient (I get about 55 to 60mpg with zero modifications), very reliable, and then I could stop paying insurance on it and not have to spend money getting it looking and feeling good (the interior is falling apart, the body is rusting terribly, no A/C system at all, heater has issues, odometer stopped working at 400,000 miles...). But on the other hand, there's this inner voice that keeps telling me that putting a black cloud mosquito fogger (hyperbole) behind my zero emissions Nissan Leaf wouldn't be exactly what I'd want.

So I've been tossing up ideas (while I still use my VW diesel for long trips) on whether I should just try a different type of engine for a pusher/generator trailer for the Leaf or should I try to attempt to improve the emissions to a reasonable degree for my Golf, or whether I should sell the bunch and by a different economy vehicle that would be some sort of happy medium.

Well, on the diesel pusher idea, I've considered water fumigation, propane fumigation, adding a catalytic converter, adding a particulate filter, adding a DEF exhaust fumigation system, etc. But one idea that seems to top them all is a fuel and water emulsification system.

The internet seems to promise that by emulsifying water into the fuel NOx emissions can be lowered by about half, and PM emissions by up to 90%. Then all I'd need is that diesel catalytic converter and I'd be set emissionswise! And there's an added benefit of lower fuel consumption.

The fear is what would 5% to 25% water in the fuel do to the injection pump and the injectors.

How I'm thinking of doing it is to put some sort of blender tank in the engine compartement. A simple fuel pump would pull fuel from the fuel tank instead of using the injector pump to do this. I'd need some sort of float in the blender tank to shut off the fuel pump. I'd also need some sort of device that meters water into the blender tank. Maybe I could figure out how much fuel the fuel pump pumps and get a small water pump and adjustable nozzle that turns on along with the fuel pump, and adjust the nozzle so that a fairly precise amount of water comes out for every amount of fuel. The injection pump would both take and return emulsified fuel from the blender tank. At the end of the run I could have a water separator that is plumbed through solenoids between the pump and blender tank that I could let the engine idle and separate for a while before turning it off in an attempt to get the water out of the injection pump before shutting off.

Anyhow, any thoughts?

[Stubby79]

Does emulsifying work better than, say, a separate water injector? You'd not kill your injection pump if spraying water in to the intake will do the same job...

Edit: Sounds like a load of hogwash to me. IF it works, it's probably beyond the average Joe to build an "emulsifier"

[Isaac Zackary]

Originally Posted by Stubby79

Does emulsifying work better than, say, a separate water injector? You'd not kill your injection pump if spraying water in to the intake will do the same job...

Edit: Sounds like a load of hogwash to me. IF it works, it's probably beyond the average Joe to build an "emulsifier"

Yes. Apparently there's a greater advantage getting the water right where combustion is occurring instead of loosely displaced within the whole cylinder.
https://www.dieselnet.com/tech/engine_water.php

[oil pan 4]

A tiny amount of water will ruin the injectors and fuel pump.
According to the EPA normal water injection on a diesel (not gas motors) is good for up to a 6% improvement in fuel economy, lowers NOx and reduces soot.
I say if it works don't fix it.
I looked into diesel emulsifier setups years ago and every lead turned out to be a scam or a load of BS.

[cajunfj40]

Hello Isaac Zackary,

Interesting idea. Pusher trailers have been done, so this should be possible. For emissions, you might consider adding a turbo and not turning up the fuel - no smoke, and really complete combustion to knock down the particulates and HC emissions. Add the water to knock down the NOx and you may not need the other stuff. Getting the new emissions gear to work right on such an old engine would be non-trivial, and probably more expensive than buying a wrecked donor car that has a newer engine with all the right bits already in a workable system.

If you do the math on the trips you take per year, biodiesel may be an inexpensive enough upgrade to further reduce the impact.

Do note that whatever method you choose, you will likely use a bit more fuel per mile with the pusher than just driving the diesel car as-is, given that the combination will be heavier than the car. YMMV.

As for emulsifying the fuel, the US Military did a lot of the work for you already. Search up "FRF" or "Fire Resistant Fuel". No actual name for the emulsifier, but enough information on the primary ingredient type to allow evaluating commercial surfactants for usage. ~10% water mix. Note: this *will* cause major issues in cold weather with line, injector and filter plugging. If you want to go on trips in the winter with this setup, you'll need a block heater, fuel line heater, fuel tank heater, etc. Basically adopt the same techniques that the Waste Veggie Oil folks use - have a second small tank of correct-for-weather straight petro-diesel for cold starts and shutdowns, coolant-heated lines and tank, etc. Don't switch the supply and return lines at the same time on shutdown - switch the supply first, run a while to purge the lines, then switch the return. Want to keep the petro-diesel clean.

Final report on the original FRF study.

More recent report, working on JP-8 version, referencing above.

Here's a later, much more comprehensive paper that appears to have the formulas, etc. in it.

Hello oil pan 4,

A tiny amount of water will ruin the injectors and fuel pump.

The US Military only partially agrees with you - at least if we're talking emulsified water rather than free water.

I risk telling someone who has a heck of a lot more experience than I do with Stanadyne pumps how to suck eggs, to mangle a metaphor, with the following digressions. Please excuse if you already know all this. If you've got countering info, I'd love to see links. Always interested in learning more!

Note: military usage is of course different than civilian usage, but digging around in the reports can yield some very useful information. Their idea of "acceptable" MTBF is on its face not something one would accept, but at least their work is really well documented and quite thorough. The appendices are excellent sources of rabbit holes of papers to go down, as well as lots of details that can give one a way to well exceed their MTBF and/or performance minimums.

Notable information from the appendices of that last report: After a 500-hour test of 10% water/6% emulsifier/balance JP-8 fuel in a Stanadyne rotary fuel pump - the type used in GM 6.2 and 6.5 IDI diesel engines, the test results were consistent with previous JP-8 testing: no fuel system failures and all injectors in good condition. A 15,000 mile HMMWV test at avg 30.5mph with a 6.5T engine had no fuel system failures and all injectors in good condition. They did find high return fuel piston wear as a cause for concern, though, which they attributed to lots of changes in throttle position during the mileage accumulation vs the 500-hour "on a stand" test.

As an addendum,
here's one of several papers the military put together about Stanadyne pumps and JP-8, fuel lubricity, etc.

[rmay635703]

My old 82 6.2 was smoke free.

You loose a little power but could turn down the IP so you never get into the smoke point.

Better FE if you smoke less.

If you insist on emissions locate an oversized antique 2 way cat, certain TDIs had them stock, they reduce VOC, CO and Soot, they can reduce NOx momentarily but are less effective at NOx

[oil pan 4]

15,000 miles is around 5% of the life expectancy of a 6.5 engine.
And they already are running into problems.
Sounds like the military was looking for something completely different than emissions and economy.
If they have to replace major parts in the fuel system every 50,000 miles because the mission needs vehicles with this water fuel system then that is what they do.

I have a pretty good idea what emulsification agent they used, use it every day where I work.

[freebeard]

5-10 years ago (that would be 2007-2012 ) someone showed up at a local show-n-shine with an electric Rabbit that had been converted as an experiment by the Sate of Oregon (lead-acid & etc.). It had a gas pusher trailer that had been made by cutting down a cabriolet. That made for a nice little trunk on the back

I now have a 1979 VW non-turbo diesel as well, so the subject of improving the efficiency is of interest. Have you seen this picture?



Right now I'm over-restoring a roof rack. Then I shall lift the rear instead of lowering the front and add front and sides air dams. Followed by a difusser with fences.

My overall strategy for more efficiency is to swap out to a Buick Lacrosse altermotor for the stop-start and KERS.

[Isaac Zackary]

Thanks for the replies! I thought I'd bring emulsified injection up since I didn't find much about it in a search on Ecomodder. But I don't think it would friendly with the injection pump and injectors so I'll be using intake fumigation instead. I've got a tight budget right now so it seems that using what I've got would be cheapest, not going and buying an expensive new gasoline engine.

[oil pan 4]

You can make a pretty nice continuous run water injection system for around $300.

To buy the water fuel emulsion additive it will cost at least $5 to $10 a gallon unless you buy a lot of it.
So if it works as well as normal water injection, best case scenario you break even. That doesn't include building the water fuel mixing rig, which no one really seems to know how to build. How much does that learning curve cost?