Diesel Engines Running Underloaded / Lube Problems?

fun

Carl, just a bit of fun from "US" old fellows teaching a young one a wee lesson that he will surely remember, check your facts and show a little respect to your elders was something drummed into me 40 years ago.

Obviously my reference to the Holiday Inn was said in jest and as you may know comes from a funny commercial over here in Florida.

temps

Now you are taking the P155, how can you not know that and yet post the BS you did earlier in this thread.

also another little hint, do you know the difference between your F's & C's.

Food for thought

A little bit of advanced thinking, is this how to produce alot of acid ?

"A second, widely acclaimed technology for reducing
NOx pollution from diesel engines is the “Humid Air Motor”
(HAM). This technology is able to reduce NOx formation
by up to 65%. In the HAM system the turbocharged
combustion air is saturated with water vapour produced
aboard the ship using sea water and engine heat.
This lowers the temperature peaks in the combustion
chamber, which are normally the main reason for NOx formation.
HAM is characterised by extremely low operating
costs due to sea water usage, decreased lube oil consumption,
very low maintenance costs and a very high
availability factor"

Someone who's been on here a bit can quickly figure out who knows what they're talking about and who doesn't. One common sign of a person who's out of their depth (or BSing, or trolling) is that they start off very authoritative and serious, then switch to lighthearted and flippant so that they can dismiss the whole exchange as just bantering.

You're correct about it poisoning the well, though. It'd be better for everyone if you didn't have to spend your time/effort calling out misinformation and could, for example, add to CaptJ's post about what the issues might be in a trans-Atlantic passage at ~50%.

Absolutely. The charge air temperature is usually your engines intake air temperature measured after it goes through the aftercooler, before it goes directly into the engine. This will alert you to how well your aftercooler is doing it's job in cooling down the charge air after it has been heated (a result of compressing air) by the Turbo's. Seawater is generally used to cool off the charge air within the aftercooler the same way a heat exchanger works, you have air flowing through the aftercooler, and seawater contained within a seperate section that the airflow flows past similar to a car radiator. I would say seawater cooled aftercoolers are most common on recreational marine diesels.

I see you have been reading up on your engineering J. Pretty good answer

I haven't read up on any engineering, I've always known what I know for the most part. I've gotten better in speaking or making sure my terminology is correct.

a version of that technique has been used on gas turbines for decades. "Fogging" is a method that sprays a mist of demineralized water into the inlet to cool the inlet air and increase power output.

I used to fly an aircraft that used water injection in front of the first stage compressor wheel to boost take-off power in "hot and high" conditions. It really makes a difference. In recips it lowers the combustion temperature and reduces NOx as stated by Yachtjocky.

It should be noted that the water used in a HAM system is not salt water, it is saturated water vapor distilled from sea water using waste heat in the same manner as the watermakers on those ships. Instead of condensing the vapor to make fresh water, the vapor is delivered to the engine intake.

terms

OK then, try removing "usually" and replace with "always" and you will be a real engineer

water

There was a process that we were asked to try out over 30 years ago where the heavy fuel was forced through two rollers with a very small clearance and fresh water was introduced on entry to them.

The theory I believe was to force the water & oil to mix to achieve the same as what we are talking about. Unfortunately there was so much s--t in the fuel it wore the rollers out and after a few days of rebuilding fuel pumps and injectors our company pulled out of the experiment. Plus we did not have the electronics avaliable in those days so the monitoring consisted of a faucet, a water hose and sight glass and with that we where expect to change the world.

FYI. CaptJ, we could change the fuel pumps on those big old engines while at sea and with them running and even adjust them but you did have to keep your fingers away from the plungers.

The shipping press has had quite a bit of noise about fuel emulsions lately. Maersk is currently in trials of a water/fuel emulsion project. Fuel emulsions are heralded as the greatest thing since reduced manning.

There are a couple of benefits, most of the proponents are now pushing the economy angle in that you can use cheap heavy fuel and when blended with up to 30 percent water it becomes an intermediate fuel like IFO 380 and is easily handled at lower temperatures.

It is supposed to improve combustion quite a bit and reduces soot, cools the reaction zone and reduces NOx. It evidently works but like your trials, the blending device is the bottleneck.

I would think that emulsions would be better for slow steaming than HAM since there isn't much waste heat left these days anyway.

If he knew anything about internal combustion or fuel characteristics this thread wouldn't exist.

C4ENG's guy may have been talking about exhaust temps but that is a completely different animal. And if he was talking C instead of F then his numbers are equally bogus.

The 650* figure (if it is C) is what we may expect the compressed charge air temperature to be at start of injection. At the end of ignition lag, when the fuel starts to burn, the temperature rises rapidly to over 1000*C in the combustion zone.

There is no practical way (or reason) to measure combustion chamber temperatures in the combustion zone and present that information to the operating engineer. The temperature of combustion is essentially the same at idle as it is a full load, the difference is the amount of heat transferred to the cylinder and piston.

There is a difference between temperature and heat, that should have been in the class notes somewhere.

We also use a turbocharger compressor (and aftercooler) cleaning system like that on large diesels but the water fogging is there to cool the inlet air to increase its density, not to clean the compressor. On aircraft turbines it is used (at least in the aircraft I flew) only on takeoff when the calculated power (torque as it was a turboprop) was below a certain amount due to hot low density inlet conditions created by weather and field altitude.

The fogging used on terrestrial GT plants uses the cooling produced by evaporation to increase the density of inlet air and increase power output. As you know, turbines are so sensitive to inlet conditions that most terrestrial plants now use a refrigeration system to cool the inlet air. That is why a GT powerplant has that huge louvered structure at the inlet side and another structure with a cooling tower nearby, it is the chill water plant. The power increase is enough to pay for that system and more.

Sea Water and SCAC Manifold Temps on CATS

Hi,

From my experiences CAT do measure this temperature.


I just looked on CAT ET which is a remote view of what's available on the local MPD.

Direct Sea Water Cooled Charge Air Coolers on C18's call it Manifold Air Temp, the sensor itself is towards the front of the Cooler Hsg on the Upper Side

On a SCAC 3516 it is called the same and the sensor itself is forward ontop of and passing through the casting that forms the base for the Charge Air Cooler retaining flange.

YUP, and also the CAT's will monitor/display fuel temperature as well and that will show how well the fuel cooler is working.....Some CAT models have the fuel cooler integrated into the heat exchanger.