Lifetime engine data recording - Caterpillar (C32 ACERT)

[Portofino]

8 L/hr for both engines in total, or each engine?

Each -per side

 

[MapisM]

Mike I don't get range figures at all on my displays, just instantaneous fuel burn but I don't know how that figure is derived, tabled injector squirt time or fuel flow meter or some other way. Also not sure how my engine load % is calculated either, is it the CAT way described by LS1 or another way?

Happy to stand corrected from Deleted User if appropriate, but I believe that also his displays don't actually show the range.
Not because I know them so well (though I had a rather accurate look at them), but because I don't see how they could.
I mean, also Cat/jfm displays do NOT give that number, I think. It's his Maretron stuff that does the job.
Engine displays alone are aware of fuel burn at any given second, but not of speed and tank size/level - numbers without which it's obviously impossible to calculate the range.

Re. how the fuel burn is calculated in your engines, again, not that I can tell for sure, but I've never seen any electronically controlled engine fitted ALSO with flow meters. It's just a sort of hair-splitting complication, when there's an ECM that can "by definition", so to speak, give that number.

Lastly, re. how the engine load is calculated (though I never thought of that before!), based on LS explanations I'm beginning to think that there isn't actually ANY other way...
But happy to stand corrected also on this one!

 

[Deleted User YDKXO]

Definitely not Mike. MTU have much shorter published intervals than Cat, AOTBE. I mean like ~50% of Cat numbers.

Wow, I'm waiting for Hurricane to comment on that. How do you know that btw?

 

[MapisM]

This is why I have got a couple of FFM100s (and 4xflow sensors) here on shelf ready to install on the gensets. But sounds like I need a repeat set for the main engines haha! Petem, open that Maretron dealership quickly and give us a forum discount!

Assuming that the sensors have a wide enough operative range (which might not be necessarily the case), why not just install one couple of them each side (port/stbd engine+genset)?
After all, you could calculate the fuel burn of each genset alone just by deducting the engine one (that you already have) from each "side" number.
And if your goal is to calculate the exact total burn, you don't actually care a lot about it anyway.

With apologies to Petem if the idea could work and I deprived him of a nice margin even before starting the job!

 

[jfm]

Each -per side

That's quite a lot then. I think mine are 9 litre/hour @ idle "turning iron" but I'll check...

 

[jfm]

Wow, I'm waiting for Hurricane to comment on that. How do you know that btw?

I've read MTU schedules on the web. Don't have time to google now. It doesn't necessarily mean MTUs are soft - it could be uber cautious German engineers in Friedrichshafen versus wild west Mercan engineers in N. Carolina

 

[Lozzer]

JFM in the scheme of things are you using that much fuel on your generators? I guesstimate 6 lph and we run for say 8 hours max.

Also I have always found it nice to have the over read as it means people accept the need to fill up sooner and reduces the risk of running out of fuel. Now that would be embarrassing.

Also having under reading tank gauges means if I rip in out if have done something really stupid..

You know what MTU stands for in the trade.

 

[MapisM]

But this year for the first time we might try slow cruising D speed

Hang on a minute, R U serious?!? As most folks around here know, I'm a strong supporter of slow cruising, but not with a boat like yours....!
Mr.Amati put all his best efforts to build something that can cruise FAST against just about any sort of sea you would want to be in with a pleasure boat, she's not meant for pootling!
I for one could never resist the temptation to hammer the throttles, with an Itama!
Also because I suspect that she might roll real bad at D speed, btw...

Looking forward to hearing more about the experience, anyway. :encouragement:

 

[jfm]

...because I don't see how they could.
I mean, also Cat/jfm displays do NOT give that number, I think. It's his Maretron stuff that does the job.
Engine displays alone are aware of fuel burn at any given second, but not of speed and tank size/level - numbers without which it's obviously impossible to calculate the range.

Yup. The engine only knows fuel flow rate as you say. The Garmin displays allow user to input tank volume, and have a page for "I just entered XXX litres of fuel" or "I just filled the tank") and so Garmin calculates range

Re. how the fuel burn is calculated in your engines, again, not that I can tell for sure, but I've never seen any electronically controlled engine fitted ALSO with flow meters. It's just a sort of hair-splitting complication, when there's an ECM that can "by definition", so to speak, give that number.

Agreed - no manufacturer would fit flow meters. but for us end users, 10% error isn't splitting hairs. It means you have a "dead" 800 litres in an 8000litres tank, because you think you're approaching empty when actually you're approaching 10% left. Sight gauges are the perfect answer but in real life they don't show the bottom 10% of the tank! (Well mine don't, annoyingly. yours?. also my keel tank is the last to empty and doesn't have a sight gauge because you wouldn't be able to see it if it did)

Lastly, re. how the engine load is calculated (though I never thought of that before!), based on LS explanations I'm beginning to think that there isn't actually ANY other way...
But happy to stand corrected also on this one!

Yup, its the only logical way and gives a perfectly useful answer

 

[Deleted User YDKXO]

Happy to stand corrected from Deleted User if appropriate, but I believe that also his displays don't actually show the range.

I will correct you then, Mapism, because I was only looking at the display 3 days ago and the range figure was definitely there You have to scroll through the pages but it's there. On my boat the remaining fuel volume in the fuel tank is measured electronically and displayed on the MMDS displays so knowing the instantaneous fuel burn, it is very easy for the MMDS system to compute the remaining range. How accurate it is I don't know and whether it's the range to empty or the range to the 15% fuel volume alarm, I don't know

I'll show you in June!

 

[MapisM]

Sight gauges are the perfect answer but in real life they don't show the bottom 10% of the tank! (Well mine don't, annoyingly. yours?

Neither. Maybe a tad less than 10%, more like 6 or 7 - not that it makes any difference, obviously.

The reason why I can answer that by heart is that my very unsophisticated tank system is made of 4 tanks, measuring exactly 1 cubic meter each, with port/stbd pairs permanently interconnected.
Therefore, the sight gauges (one per side) are one meter high, and only the last 6/7 centimeters are not visible.
The big difference is that by the time fuel is down to 6cm, with those 240 litres I can still cruise for a dozen of hours, while with the goodship M2 you would be at risk of not reaching PV from the Lerins....

 

[jfm]

I will correct you then, Mapism, because I was only looking at the display 3 days ago and the range figure was definitely there You have to scroll through the pages but it's there. On my boat the remaining fuel volume in the fuel tank is measured electronically and displayed on the MMDS displays so knowing the instantaneous fuel burn, it is very easy for the MMDS system to compute the remaining range. How accurate it is I don't know and whether it's the range to empty or the range to the 15% fuel volume alarm, I don't know

I'll show you in June!

You'd want to be cautious using such a range figure. If tanks are perfect cuboids it has some chance of being right enough. It is likely measuring varying resistance of a tank sender and deducing remaining fuel from some parameters initially entered when the boat was first set up. They probably set it up so it understates the range of course, to be safe

Separately mike, does MMDS know the boat's SOG via nmea, so it can tell you instantaneous litres per mile? That's much more use than LPH

 

[MYAG]

The thing about squirt back into tank is you don't know the genset burn. you can estimate it of course, but your genset hours are very high and the lph varies substnatially with electrical load, so an estimate is going to be a bit dodgy. This is why I have got a couple of FFM100s (and 4xflow sensors) here on shelf ready to install on the gensets. But sounds like I need a repeat set for the main engines haha! Petem, open that Maretron dealership quickly and give us a forum discount!

Yes agreed, get going Petem.

Actually my genset consumption is quite predictable, as I have to run them 24/7 when not berthed on shorepower this allows me to measure fairly accurately the fuel burnt over a period of a week or two at anchor without engines ever running, which iirc was about 4.5 l/h which was equal to an average hourly load of 50% (c60amps) during the period.

 

[jfm]

JFM in the scheme of things are you using that much fuel on your generators? I guesstimate 6 lph and we run for say 8 hours max.

Also I have always found it nice to have the over read as it means people accept the need to fill up sooner and reduces the risk of running out of fuel. Now that would be embarrassing.

You're right - genset fuel is small. In a week with lots of anchor and relatively little running then the 4 or 500 litres of genset fuel would be nice to know about, but I can only justify it by geekishness not by proper logic
Actually I personally do not like built in safety factors. I'd much rather know that I have precisely 600 litres on board, then have a system that tells me I have nil when really there are 600 litres left. I prefer to create my own safety margins. Running out of fuel isn't a "risk" in my book because there is nothing unpredictable about it, if you have the data

 

[MapisM]

I will correct you then, Mapism, because I was only looking at the display 3 days ago and the range figure was definitely there

Doh! I did remember your nice tank level electronic gauges, but I would have sweared that they weren't on the engine displays.
Well, in this case, obviously MAN did a good job of making the MMDS ready to take two inputs (not only the tanks level, but also the speed).
And Ferretti integrated them very nicely!

By chance, did you ever notice how rapidly the range number change, by varying the speed?
I mean, obviously there's a big range difference between 10 and 30 kts, and unless it's also possible to key in an estimated future speed, the only assumption the displays can make is that you will continue to cruise at the same speed that you are keeping at any given moment (or an average of the last X minutes, whatever). Just curious...

 

[MYAG]

That's quite a lot then. I think mine are 9 litre/hour @ idle "turning iron" but I'll check...

Really? Sounds a lot to me. Mine are at 3l/h "turning iron" (looking at them now) and 6/7/lh idle speed in gear each side.

 

[jfm]

Neither. Maybe a tad less than 10%, more like 6 or 7 - not that it makes any difference, obviously.

The reason why I can answer that by heart is that my very unsophisticated tank system is made of 4 tanks, measuring exactly 1 cubic meter each, with port/stbd pairs permanently interconnected.
Therefore, the sight gauges (one per side) are one meter high, and only the last 6/7 centimeters are not visible.
The big difference is that by the time fuel is down to 6cm, with those 240 litres I can still cruise for a dozen of hours, while with the goodship M2 you would be at risk of not reaching PV from the Lerins....

Yep! I'd love to have sight gauges down to 0%, because its when the fuel is low that you really need them!
I'd make it from the Lerins, just (At like for like speed, I'm 8 litres/mile, btw, iirc)

 

[MapisM]

Separately mike, does MMDS know the boat's SOG via nmea, so it can tell you instantaneous litres per mile?

Well, based on previous M reply, the MMDS is bound to know the speed somehow, otherwise it couldn't calculate the range (hence my previous question/curiosity).
Therefore, also the L/miles numbers is probably available, I reckon...

 

[jfm]

Really? Sounds a lot to me. Mine are at 3l/h "turning iron" (looking at them now) and 6/7/lh idle speed in gear each side.

I don't doubt that's what the computer says but that strikes me as very low. I'll check mine at w/e. If yours are 3 @V12, mine are 9@V12, Porto's are 8 @inline 6, it feels like the measurement (nozzle calibration of fuel volume to PWM length) is wildly out at low flow rates. I could believe that to be the case - quite plausible

 

[jfm]

Well, based on previous M reply, the MMDS is bound to know the speed somehow, otherwise it couldn't calculate the range (hence my previous question/curiosity).
Therefore, also the L/miles numbers is probably available, I reckon...

Yes, of course (doh!)