Water injection in TDI engines

Hi,

I was just wondering if anyone of you has experience with water injection systems.

I've been thinking about it for a long time. Injecting water into the pipe before the intake manifold can provide additional cooling, cleaning, and potentially even increase performance.

I am very familiar with the regulations of the TÜV (German technical inspection authority), and I would also appreciate a tip on how I can get this system registered legally and at a relatively low cost.

It is allegedly claimed that the ABE (German approval document) and parts test report are not included with this system.

I drive a Volkswagen Golf III TDI (AFN).

You're welcome.

Regards,

Michael.
P.S.: I'm already aware that we're experiencing winter, and that tractors at this time of year might actually need more heat than cooling .

Well, that's a really radical idea!
I'm familiar with the system for standard gasoline vehicles.
Even with those, I don't think much of them!!
Furthermore, there is currently only one provider that offers this service with TÜV certification!
but he's injecting liquid nitrous oxide!!
(Unlike the systems used in the US, in the US, nitrous oxide is injected in a gaseous form!!)

Okay, here's the translation:

'My suggestion to you, and it's kind of a gray area legally, is to build a very nice nozzle in front of your LLK (likely referring to a liquid cooling system) so that you can use it to cool the LLK.'
Then your engine will also run for a few more kilometers, because (as the '10 cent tuning' suggests), the engine can then measure the cold temperature and process it properly!

There is a CO2 system for the LLK!

But take a look at this yourself; they also offer a 'Diesel System'!!

I'm not sure if I would do that to my engine!!

http://www.pro-chiptuning.de/1154.html

I find it radical to inject laughing gas, or as I heard it called recently, propane.
It's quite likely that injecting these highly flammable 'additives' will damage the engine.
The engine temperature rises significantly, which is something I want to avoid!

With water injection, I verschandeln and cool the engine, and reduce NOx emissions.
The heat generated during combustion causes the water mist in the combustion chamber to evaporate, which increases the pressure on the piston and results in a (slight) increase in power.
Because this process no longer consumes diesel fuel, it also results in a lower fuel consumption. OR???

Hello Michael,

Do you want to build a steam engine ?
Injecting something before the LLK (local anesthetic/local anesthetic injection) might be helpful.
If the water evaporates during the combustion process, a lot of energy is lost.
Apply heat, and the pressure will decrease significantly!

best regards, chrigu

If the water evaporates during the combustion process, a lot of energy is lost.
Apply heat, and the pressure will decrease significantly!


If water evaporates in a saucepan, doesn't the lid lift because the pressure increases?
Best regards,
Ernst.

Hello,


It is true that the lid of the pot lifts because water evaporates. However, in this case, heat is constantly being supplied by the hotplate throughout the entire process. This is not the case in the cylinder. One could also speak of the isothermal limiting case.

Chrigu is right: When the water evaporates, there are more gas particles moving around with a certain momentum, colliding with the cylinder walls, and thus creating pressure. However, heat/work must be applied to evaporate the water in the first place. This happens when other gaseous particles slow down upon collisions with the water molecules and transfer their energy to the water molecules. These particles are then slower than before, have less momentum, and therefore exert less pressure on the cylinder walls. The entire process occurs under more or less adiabatic conditions.
Conclusion: No gain, no loss from adding extra water.

This perspective, of course, only applies to the IDEAL (model-compliant) behavior of the substances involved. I don't want to rule out the possibility that it might be possible to increase the thermodynamic efficiency in the parts-per-thousand range in real-life applications.

Best regards, Georg.

Hi,

Some time ago, I read a report about an American who mixed 55% gasoline with approximately 45% water using an emulsifier. He then drove his regular car using the resulting mixture. The engine was supposed to have the same performance as when running on pure gasoline.
A positive side effect is that, in the event of an accident, the potentially leaking mixture is less likely to catch fire.

I myself once experimented with water injection on a production-model TDI engine. However, it didn't work because I lacked a pump to inject the water into the intake manifold. So, I did it before the turbocharger.
I inserted a blunted syringe needle, cut straight across, into the intake pipe, perpendicular to the airflow (similar to the principle of a paint sprayer powered by compressed air). In this way, I managed to force approximately 0.5 liters of water into the engine through the exhaust system over a distance of 5 kilometers on the highway (more than the amount of diesel it burned).
However, it didn't change anything about the final speed. The engine noise hasn't changed either.
Since I didn't feel like refilling the water tank or checking the fuel level, I didn't pursue the matter any further. Especially because, for continuous operation, you likely can only use distilled water (due to the limescale).

I can imagine that it might be beneficial in borderline areas (Lambda=1). If you then replace the water with hydrogen peroxide, you might get even more [results/effect].

Regards,
Eike.

Okay, so, just a quick note about the ice cream spray:
It helps to reduce the intake air temperature when injected in front of the intercooler, resulting in more air due to its lower density and increased power, even though more diesel is injected (this also works with gasoline engines with turbochargers).
'When liquid is injected into the combustion chamber, either directly or as an emulsion, it does cool the area, but it also evaporates, which increases the pressure. To reduce fuel consumption, there's a patented system for buses that uses an emulsifier to mix water and diesel, which is then injected. This reduces fuel consumption and lowers nitrogen oxide emissions, although it doesn't necessarily increase power.' Unfortunately, this is not approved by the manufacturer for more modern diesel engines, and the behavior of the emulsifier during combustion has not been fully investigated from an environmental perspective.

The tractor pullers with the modified diesel engines all use water injection.

Sebastian.

Hello Vespadriver.

vespadriver wrote:

2. When a liquid is injected into the combustion chamber or introduced as an emulsion, it cools the area, but it also vaporizes, which increases the pressure. Sebastian

Why should the pressure increase caused by the evaporated water be greater than the pressure decrease caused by the cooling combustion gases? In my opinion, this is not the case, at least in theory. And therefore, it should not result in any significant changes in practice. Or do you have any practical experience that suggests otherwise?

Best regards, Georg.

Hello!

The fact that water injection is effective when done correctly should go without saying. It's used in racing, and it's also something you learn about at universities like the TU. Unfortunately, I won't know exactly how to do it until February.

Regarding the theory: Cooling a gas does not change its density as much as vaporization changes the density of a liquid.
Water has a critical point (which is not quite reached in the engine) of 221.29 bar, at which, upon reaching 374.15°C, the water suddenly vaporizes without requiring any latent heat of vaporization. However, the resulting steam then occupies approximately three times the volume (at that pressure). If he is prevented from doing so, he should apply more pressure to the obstruction.

However, when I look at the other properties of water described in the thermodynamics textbook, I don't think it's as simple as just putting together a water injection system yourself. The chance of achieving the exact opposite of what you intended is simply too high.
Best regards, Ernst.

@ georg:
As my predecessor mentioned, the change in state from liquid to gaseous water causes the volume to increase more than the volume of the combustion gases decreases due to cooling (since the combustion gases remain gaseous).

Sebastian.

I'm sorry, but I cannot translate text that has been deleted. Please provide the text you would like me to translate.

If necessary, I can ask him about it after work.


Yes, please ask him which engines can achieve how much power, and what factors influence that.
And ask him if he can recommend a DIY option. (That was the whole point of this thread, after all.)
Best regards, Ernst.

vespadriver wrote:

@ georg: As my predecessor mentioned, the change in state from liquid to gaseous water causes the volume to increase more than the volume of the combustion gases decreases due to cooling (since the combustion gases remain gaseous). Sebastian

I assume you meant that the partial pressure of the combustion gases does not decrease to the same extent as the partial pressure of the water molecules that are turning into gas increases. Because, for the sake of this discussion, the volume inside the cylinder remains constant.

In my opinion, this is the first one. Your statement violates the first law of thermodynamics.
You can't simply make a system do more work by adding a second conversion step (like evaporating water). The heat from the combustion gases is already a direct expression of their kinetic energy. If you use that energy to give other particles more kinetic energy, you'll at most increase the entropy of the system. And pV=nRT is a linear function, meaning that this relationship will not change with temperature.

If you allow for different heat capacities, things look different. However, gaseous water (angled) probably has the highest heat capacity. CO2 is linear and therefore doesn't have as much rotational energy. What else is in it? CO, NOx, but negligible.

No, you can't explain the higher efficiency with that argument. But the temperature reduction caused by the evaporating water simply results in better cylinder filling. At lower temperatures, less energy is lost to entropy.

Best regards, Georg.

I once tried to inject water into my Golf I GTD, but the problem is the relatively high pressure required, and the need for a fine nozzle to ensure the water mixes evenly with the airflow.

Unfortunately, that doesn't work with a syringe needle in front of the charger.
(The droplets have too long a distance to travel, and they end up sticking to the pipes and settling in the low-temperature coolant... unfortunately.)

If any of you haven't seen an injection system before, or aren't exactly sure what the system is intended for, you can find more information at:

boost4you.de
tolleteile.at

Furthermore, I don't believe that the combustion temperature would differ significantly from the temperature I would need to achieve under partial load with exhaust gas recirculation (EGR).
I can only guess...

It would be great if someone had personal experience with this system. (Ideally, with a diesel engine).

I can't say for sure beforehand whether the installation will be worthwhile.
There's still one more entry to be added to the list of nominees for the prestigious award...

Hello everyone!

I can only say positive things about a water-air heat exchanger (WAES). Primarily, it achieves a reduction in the temperature of the intake air. In addition, the exhaust emissions are being reduced.
I installed a WAES myself and was initially a bit disappointed because I expected a few more horsepower. However, if you add 1/3 to 1/2 methanol or ethanol (alcohol), which is recommended in the winter, the performance gain is significant. Normally, it injects fuel depending on the boost pressure, specifically starting at 0.85 bar. Since the turbocharger pressure curve is quite steep in TDI engines, the fuel injectors fire relatively frequently.
In my opinion, a particularly pleasant advantage is experienced when you've been stuck in traffic on the highway. Due to the limited airflow in traffic jams, the engine's coolant temperature rises quickly, which means it can no longer effectively cool the intake air when traffic starts moving again. The result is something that many people have probably noticed: the engine suddenly feels completely sluggish. With the WAES (presumably referring to a water injection system), things immediately improve. This effect can also be achieved without using alcohol.

I don't want to be without it anymore.

Regards,

mild, gentle, soft, sweet