DIY project: Adding a fuel consumption data to older diesel

As my DIY rebuild of Yanmar 6LY went into the "field testing" phase, I wanted to document and share my next engine-related project of getting the fuel consumption data into the Nmea 2000 network, and having it shown on the chart plotter.

The reason for adding this feature

2x 370HP diesel engines drink a considerable amount of fuel, and I want to know what RPM I have to keep in the current conditions for the best MPG. Because the savings (or waste) can be in $100s if not $1000s during a single boating season.

The existing options

I want this data available in Nmea 2000 network and found only 2 options available:

1) A well-known Maretron set. The system will require a fuel flow monitor and 2x fuel flow sensors for each engine. This will cost ~$1200 per engine. Total $2400+ for two engines. And, I think, this will also require a Maretron unit to program and set everything up, so the total cost will be close to $3000.

2) Another option is an unknown unit from Eastern Europe called Delta PN 100 flowmeter. That company supplies the European trucking and generator industry with flow meters and does not advertise to boaters because that market is much smaller and boaters do not buy those units in bulk.

Their monitors fit my requirements perfectly and the total cost of everything to install, program, and use the unit is less than half of Maretron or 1/3rd for a two-engine configuration. A saved $2000 will buy a lot of diesel.

I already used the first version of this unit 4 years ago on my single-engine trawler, and the data was only partly useful. If I connect to the unit with a computer (it has a USB interface), I got very precise consumption data for a set period of time: supply, return, and the difference. It was checked against my fill-ups and was spot on.

But the instant consumption data sent to Nmea 2000 network, which was the most interesting to me, was useless because it fluctuated from anywhere from 0 GPH to 10 GPH every second. They sent me multiple firmware upgrades, which did not help much. The problem was with sending the instant data into the Nmea network instead of averaging it for a few seconds before sending. I sold that old boat at that time so that exercise ended in 2019.

With a new boat, I decided to give them another go, and they assured me the current version included a user-adjustable averaging setting which solved the instant consumption data issue I was having.

The total cost of the whole system for two engines was $795 USD
Shipping to Canada was $221 USD
For a total of $1016

Here is the photo of what I received.
(only one sender unit is shown, but i've got 2 of them for two engines)

Each unit has 4 connections:

- Fuel In
- Fuel Out
- Return In
- Return Out

and will record the fuel supplied to the engine and fuel returned from the engine to the tank and calculate the difference. That difference is sent to Nmea 2000 network as the current fuel consumption number.
This new version also allows users to adjust the averaging time to calculate this consumption number and I plan to set it to something between 15 and 30 seconds.



I also attached the specs and manual for this unit which I received in 2019.
I did not get the new one yet, but it will be very similar.

Delta PN 100 flowmeter manual

If the latest version of this unit and firmware will work as expected, it has great potential to solve the problem of getting the precise fuel consumption data for older diesel engines without rail injectors as a much less expensive and easier-to-install option.

As a part of this upgrade, I will also be installing Nmea 2000 network and connecting the existing older Raymarine equipment to Nmea 2000.
Let me know if you are also interested in details on this part.

I'll keep you posted on the installation and testing.

Waterant said:

As my DIY rebuild of Yanmar 6LY went into the "field testing" phase, I wanted to document and share my next engine-related project of getting the fuel consumption data into the Nmea 2000 network, and having it shown on the chart plotter.

The reason for adding this feature

2x 370HP diesel engines drink a considerable amount of fuel, and I want to know what RPM I have to keep in the current conditions for the best MPG. Because the savings (or waste) can be in $100s if not $1000s during a single boating season.

The existing options

I want this data available in Nmea 2000 network and found only 2 options available:

1) A well-known Maretron set. The system will require a fuel flow monitor and 2x fuel flow sensors for each engine. This will cost ~$1200 per engine. Total $2400+ for two engines. And, I think, this will also require a Maretron unit to program and set everything up, so the total cost will be close to $3000.

2) Another option is an unknown unit from Eastern Europe called Delta PN 100 flowmeter. That company supplies the European trucking and generator industry with flow meters and does not advertise to boaters because that market is much smaller and boaters do not buy those units in bulk.

Their monitors fit my requirements perfectly and the total cost of everything to install, program, and use the unit is less than half of Maretron or 1/3rd for a two-engine configuration. A saved $2000 will buy a lot of diesel.

I already used the first version of this unit 4 years ago on my single-engine trawler, and the data was only partly useful. If I connect to the unit with a computer (it has a USB interface), I got very precise consumption data for a set period of time: supply, return, and the difference. It was checked against my fill-ups and was spot on.

But the instant consumption data sent to Nmea 2000 network, which was the most interesting to me, was useless because it fluctuated from anywhere from 0 GPH to 10 GPH every second. They sent me multiple firmware upgrades, which did not help much. The problem was with sending the instant data into the Nmea network instead of averaging it for a few seconds before sending. I sold that old boat at that time so that exercise ended in 2019.

With a new boat, I decided to give them another go, and they assured me the current version included a user-adjustable averaging setting which solved the instant consumption data issue I was having.

The total cost of the whole system for two engines was $795 USD
Shipping to Canada was $221 USD
For a total of $1016

Here is the photo of what I received.
(only one sender unit is shown, but i've got 2 of them for two engines)

Each unit has 4 connections:

- Fuel In
- Fuel Out
- Return In
- Return Out

and will record the fuel supplied to the engine and fuel returned from the engine to the tank and calculate the difference. That difference is sent to Nmea 2000 network as the current fuel consumption number.
This new version also allows users to adjust the averaging time to calculate this consumption number and I plan to set it to something between 15 and 30 seconds.

I also attached the specs and manual for this unit which I received in 2019.
I did not get the new one yet, but it will be very similar.

Delta PN 100 flowmeter manual

If the latest version of this unit and firmware will work as expected, it has great potential to solve the problem of getting the precise fuel consumption data for older diesel engines without rail injectors as a much less expensive and easier-to-install option.

As a part of this upgrade, I will also be installing Nmea 2000 network and connecting the existing older Raymarine equipment to Nmea 2000.
Let me know if you are also interested in details on this part.

I'll keep you posted on the installation and testing.

Click to expand...

Very interesting, but WOW, that manual is really hard to decipher.

Agree. I tried reading it but obviously it was written by a person that wasn’t completely comfortable with English. I would be interested in it if it works and I could trust it being a good system. But as I read it almost everything said for the owner to correct the problem…

Who reads the manual anyway? I used it only for the pictures.

As I remember, the only tricky part was connecting to USB.
The unit had to be powered in a certain sequence before or after USB was plugged in so the program could recognize it.

I have some simplified instructions from them somewhere in emails.

And the only setting to be changed is probably the time interval for averaging and maybe Nmea 2000 device id, I'll keep it on default at first to see if it works.
I will prepare step by step instructions.

Because you say it worked in the past at the longer term usage (not moment by moment), it seems they have controlled for temperature variation between in and out which is a problem with the more basic wheel units.
Is there a minimum flow it'll measure? Our NA's return very little.
Sorry - my bad. Reading the manual you added shows 5lph at 0.5% error. Much better than they used to quote when I looked about 3-4 years ago.

Looking forward to hearing how you go!

mcarthur said:

Is there a minimum flow it'll measure? Our NA's return very little.
Reading the manual you added shows 5lph at 0.5% error.

Click to expand...

for Delta PN 100 the min is 1 Lph and max flow rate is 100 Lph.
they do have larger model Direct PN 250 with min of 2 Lph and max flow rate is 250 Lph. I wonder if I had to get that one instead for my engines.

my Yanmars 6LY suppose to have min consumption of 12 l/hour and max consumption of 80 l/hour, but this is the difference between the fuel supplied to the engine and fuel returned to the tank.

The fuel flow to the engine could be much more than that but I could not find any data on Yanmar 6LY about the flow to the engine vs the return flow to the tank, so this can be a potential problem.
Hopefully, it will be very little fuel returned back to the tank at higher RPMs, and the flow to the engine will stay under 100 l/hour or 26 gph.

If anyone has any knowledge about the flow rate on those engines, please let me know.

on the boatdiesel.com i found i reference:
"Floscan tech told me the Yanmar 6LYA-STE 350 has a flow rate of 70 gallons per hour."

if this is true, my max flow rate may be 264 Lph so I will need Direct PN 500 with min of 5 Lph and max flow rate is 500 Lph.
I asked the manufacturer if they still offer those models.

Waterant said:

for Delta PN 100 the min is 1 Lph and max flow rate is 100 Lph.
they do have larger model Direct PN 250 with min of 2 Lph and max flow rate is 250 Lph. I wonder if I had to get that one instead for my engines.

my Yanmars 6LY suppose to have min consumption of 12 l/hour and max consumption of 80 l/hour, but this is the difference between the fuel supplied to the engine and fuel returned to the tank.

The fuel flow to the engine could be much more than that but I could not find any data on Yanmar 6LY about the flow to the engine vs the return flow to the tank, so this can be a potential problem.
Hopefully, it will be very little fuel returned back to the tank at higher RPMs, and the flow to the engine will stay under 100 l/hour or 26 gph.

If anyone has any knowledge about the flow rate on those engines, please let me know.

Click to expand...

Don't you need the Delta model, not the Direct model? Or maybe I misunderstood the difference, which is very possible.

You are right, it has to be Delta PN 100, 250 or 500
Looks like I will need Delta PN 500 if my engine flow is indeed 70 gph
And I did ask manufacturer about getting those larger Delta models but referenced "Direct" here. My bad, it was a long day ..

Around $1K for twin diesels is certainly an improvement over the Maretron option, thanks!

Still, that's a lot for four flow sensors and a small computer. I've been playing with some home automation stuff. An ESP8266 or even ESP32 processor is only a few bucks, and can be easily programmed using Arduino or ESPHome. Flow sensors must be pretty common in industrial environments. I can't imagine it takes more than $5 or so to produce them, so even with a fair mark-up they should cost tens of dollars each, not hundreds.

I see a huge market opportunity here, or an open-source project.

I hope it works!. I tried David Burtons Optio system with our 6lya-STE engines and they never delivered any kind of useful data David Burton said to return them but never replaced them or refunded the purchase, not a guy to do business with.
Did you think about replacing the CAV on engine fuel filters with spin ons?.I discussed a little with Tony Athens, but haven’t done it yet. Replacing those filters is my least favorite maintenance item on those engines.
Great job on your rebuild!
Eric

CaptTom said:

Flow sensors must be pretty common in industrial environments. I can't imagine it takes more than $5 or so to produce them, so even with a fair mark-up they should cost tens of dollars each, not hundreds.

Click to expand...

i conder anything in the fuel line between the tank and the engine as mission-critical equipment and would not use any cheap flow sensors there.
and industrial-grade sensors would cost the same or more than these Delta PN units. plus, you have to do the temperature compensation, which would not be possible with cheap flow sensors, and everything has to be connected together in a tight way acceptable for the engine room, which is different from doing that on a table in the office.

I feel like there is no way to do this for less than $370, which is the cost of the smaller Delta PN unit. So, why bother if there is a ready-to-use proven and industrial-grade solution at a reasonable price available?
the major cost here is the shipping from Europe and the computer interface programming module, which you really need only once.

I think, a better way to go to the market with this would be buying those units in bulk, ship to US, and programming them for each order - most users will not need the computer interface if the unit has a unique network ID and averaging time interval set to some optimal value.

Quick update:

The manufacturer's engineer confirmed that i can use Delta PN 100 for Yanmart 6LYA.
He said there would be no failure because my flow can be higher than the unit's max flow, but it may be less accurate at the engine's max RPM. and I do not plan on running at max RPM anyway so i will go ahead with the installation.

I connected the unit to my computer and configured it for Engine No 1, Nmea 2000 output and average time of 10 seconds.

Connection is a bit tricky so I wrote down the steps:

1) Download drivers for Destination CAN
https://mechatronics.by/en/products...sens-destination-can-k-liners232rs485can-usb/

2) Unzip the file and install 2 drivers below:
- \Drivers_Destination-02\ST-Virtual comport driver\Win8\dpinst_amd64.exe
- \USB_GD_Virtual Com Port Driver_v2.0.2.2673\x64\USB Virtual Com Port Driver.exe

3) Reboot

* The below sequence is important for a successful connection

4) Keep "Delta PN 100" unit disconnected for now

5) Connect "Destination CAN" to USB in your PC

6) Run Configuration utility:
MXTUserConfigDDRT_1_26\MXTUserConfigDDRT_1_26\MXTUserConfigDDRT.exe
Can be downloaded here: https://drive.google.com/drive/folders/1KVpo3h-gDR0KPTRnRZIPEz2orXS-lt-B

7) Connect "Delta CAN 100" to "Destination CAN". This step has to be last because the sensor has active k-line settings mode only for 10 sec when the sensor is powered on, then k-line wire switches to pulse output mode.



8) In the Configuration utility, click "Reread data", you should get "Model", "“Serial number" and other information filled in (see attachment)
- Change "Digital output" to "CAN NMEA 2000"
- Change "Engine number Nmea 2000" to 1 or 2 (if you have multiple engines)
- Change "Data producing interval" to 10 s (the best value will require some experimentation)
- Click “Save configuration.”



The unit is ready for installation in the engine room and connection to Nmea 2000

I wonder if the unit you used four years ago and failed with could have benefitted from the use of the damping cylinders at the flow sensors the FlowScan I have installed. The instantaneous readings you got might have been a bit more realistic.

Great report, thank you very much for sharing in such detail.
Does you MFD show total fuel used or just a flow? Can you reset after a cruise or when you refill the tanks?

GrahamL said:

Does you MFD show total fuel used or just a flow? Can you reset after a cruise or when you refill the tanks?

Click to expand...

I did not connect this new unit yet but if I remember correctly from my previous experience with it, the unit sent only the instant fuel consumption number (Lpm or Gpm) into the Nmea 2000, and it was up to MFD to total it for the trip duration and show other numbers like total fuel used, MPG and etc.

On this boat, I installed a new Simrad Go9 Xse connected to Nmea 2000 and it will take the data from this Delta sensor and do all the data processing to show me the numbers i need.
I went with Simrad Go9 because it supports all kinds of third-party maps (my favorite Navionics, C-Map, and a few others), and the data can be customized in much more ways than the data on Garmin units.

I'm hoping to see:
- Instant consumption
- MGP
- Range left in miles.

* I can not confirm if it's possible until everything is installed and configured.

Just an update: the units are connected and tested.

Here is the screenshot of the latest settings.



The important part is the "Flow filter" set to 30s - this is a smoothing average to avoid the consumption data jumping all over the place.
on my quick test, it worked beautifully, and the consumption data stayed constant on idle and increased at 1500 RPM

Here is the graph of the inflow and outflow of the fuel from the sensor on idle and you can see the jump when i increased RPM to 1500



I did this on the last day on the boat and did not have time for more testing or even to take photos of the actual installation in the engine room. Coming in a couple of weeks.

a couple of things to resolve:

1) is how to set the data coming from 2 engines in Nmea2000. I already set engine ID to 1 and 2 on both senders. i think this is something i will have to set on the Simrad chart plotter and will probably have to check with their support about that.

2) another little issue is with the max flow. Delta CAN 100 unit i have is rated for 100 Lph maximum and as you can see from the chart, my engine is pumping 250 Lph at 1500 RPM. Will probably be 400 Lph at 2800 RPM cruising.
so for my engines, I would need Delta CAN 500 (i think they have 100, 250 and 500)
I asked their support and they said Delta CAN 100 will not blow up but the accuracy may be lower.
I'll keep playing with what i have for now, but if someone with smaller engines (i think they spec up to 150 HP) is interested, I can sell those units at cost and will order larger units.

How is the system working?

The units look similar to the more expensive airmar product.

hytedin said:

How is the system working?

Click to expand...

Everything is connected, but both engines are still winterized. When I'm back on the boat in a couple of weeks, I'll start testing this system and post the result.

Thank you!

Quick question: Why have a sensor on each engine? Same engine so same flow rate.

Personally it would bother me to monitor one but not the other.

rslifkin said:

Personally it would bother me to monitor one but not the other.

Click to expand...

Why? Is there something I'm missing-i.e. early detection of a problem?

Mac2 said:

Why? Is there something I'm missing-i.e. early detection of a problem?

Click to expand...

That would be one reason, the other is that if both are monitored then the system can give a correct number for total fuel burn without having to do mental math. Same story if it does MPG calculation. And for no good reason at all, the lack of symmetry would bother me if I didn't have the same monitoring on both engines.

Looking forward to the update, thanks!!

Waterant said:

As my DIY rebuild of Yanmar 6LY went into the "field testing" phase, I wanted to document and share my next engine-related project of getting the fuel consumption data into the Nmea 2000 network, and having it shown on the chart plotter.

The reason for adding this feature

2x 370HP diesel engines drink a considerable amount of fuel, and I want to know what RPM I have to keep in the current conditions for the best MPG. Because the savings (or waste) can be in $100s if not $1000s during a single boating season.

The existing options

I want this data available in Nmea 2000 network and found only 2 options available:

1) A well-known Maretron set. The system will require a fuel flow monitor and 2x fuel flow sensors for each engine. This will cost ~$1200 per engine. Total $2400+ for two engines. And, I think, this will also require a Maretron unit to program and set everything up, so the total cost will be close to $3000.

2) Another option is an unknown unit from Eastern Europe called Delta PN 100 flowmeter. That company supplies the European trucking and generator industry with flow meters and does not advertise to boaters because that market is much smaller and boaters do not buy those units in bulk.

Their monitors fit my requirements perfectly and the total cost of everything to install, program, and use the unit is less than half of Maretron or 1/3rd for a two-engine configuration. A saved $2000 will buy a lot of diesel.

I already used the first version of this unit 4 years ago on my single-engine trawler, and the data was only partly useful. If I connect to the unit with a computer (it has a USB interface), I got very precise consumption data for a set period of time: supply, return, and the difference. It was checked against my fill-ups and was spot on.

But the instant consumption data sent to Nmea 2000 network, which was the most interesting to me, was useless because it fluctuated from anywhere from 0 GPH to 10 GPH every second. They sent me multiple firmware upgrades, which did not help much. The problem was with sending the instant data into the Nmea network instead of averaging it for a few seconds before sending. I sold that old boat at that time so that exercise ended in 2019.

With a new boat, I decided to give them another go, and they assured me the current version included a user-adjustable averaging setting which solved the instant consumption data issue I was having.

The total cost of the whole system for two engines was $795 USD
Shipping to Canada was $221 USD
For a total of $1016

Here is the photo of what I received.
(only one sender unit is shown, but i've got 2 of them for two engines)

Each unit has 4 connections:

- Fuel In
- Fuel Out
- Return In
- Return Out

and will record the fuel supplied to the engine and fuel returned from the engine to the tank and calculate the difference. That difference is sent to Nmea 2000 network as the current fuel consumption number.
This new version also allows users to adjust the averaging time to calculate this consumption number and I plan to set it to something between 15 and 30 seconds.

I also attached the specs and manual for this unit which I received in 2019.
I did not get the new one yet, but it will be very similar.

Delta PN 100 flowmeter manual

If the latest version of this unit and firmware will work as expected, it has great potential to solve the problem of getting the precise fuel consumption data for older diesel engines without rail injectors as a much less expensive and easier-to-install option.

As a part of this upgrade, I will also be installing Nmea 2000 network and connecting the existing older Raymarine equipment to Nmea 2000.
Let me know if you are also interested in details on this part.

I'll keep you posted on the installation and testing.

Click to expand...

Very interesting! I have a single Volvo-Penta 200 hp engine and I would like to install something similar.

Waterant said:

The total cost of the whole system for two engines was $795 USD
Shipping to Canada was $221 USD
For a total of $1016

Click to expand...

I have also looked into adding a fuel flow meter to my 80 hp Ford Lehman. I already did an installation for the 50 hp outboard on my C-dory. I was able to locate a new (discontinued) Faria FFM027, which is a fuel flow monitor and totaller. Important for my use for both small engines is that the monitor is able to sense relatively minute flow quantities. The Faria can monitor down to about a 1/10 of a gallon per hour and so is accurate for either engine at idle. The common internet claim for the discontinuation of the Faria unit is that, for most people, it doesn't matter whether you burn 1/10 or 2/10 per hour. Nobody is going to pay $350 to install a gizmo that might save you 30 cents a day.

With the $350 Faria no longer available, I had to go with something else. A company named Digiflow made a flow meter for gas and diesel that monitored down to .005 liters per minute (.3 liters per hour) and a max of 30 liters per hour. That's plenty for my 4 cyl. Lehman. Cost was $45, including shipping. This unit has also been discontinued, but the company still makes a similar flow reading system for water. Best I can tell after looking at the specifications, the difference between the two models is that the model sold as a gas/oil flow meter has a gas resistant o-ring. The rest of the flow sensor's materials are listed as extremely tolerant to gas/diesel/hydraulic fluid, etc. I bought a couple of the water-rated sending units and some Viton o-rings ($6) to test my theory about the gasket, but haven't had a chance to swap out the gasket yet.

Here are the issues that I see about whether to use a $50 fuel flow monitor or a $1K-$3K system. First, how much does it really matter if the sender unit has a limited life-span because of either material degradation or wear? Second, how much does it matter that a simple system doesn't measure the return to the tank from the injector pump?

As to the first question, I can temporarily install the $50 sender/meter and run tests for a day or two and record the burn rate and speed at 600 rpm, 1,000 rpm etc., on up to WOT. I then make myself a nice graph and calculate the "sweet spot," if any . Do I really need to look at the meter next week when I'm travelling at 1,000 rpm once I have the graph? Just look at the graph. The meter would just be an extraneous gauge. Good thing I didn't pay $1,000 for it and permanently mount it amongst the boat's important gauges.

As to the second issue on the amount of return fuel from the injector pump not being monitored, it really doesn't matter. First because the Lehman system returns so little. I've calculated that my fuel tank sight gauges are about 5.8 gallons per inch in the sight tube. I've run 8 hours at 1650 rpm out of one tank with the return going to the other tank (having marked the sight tube with tape.) One would never do this with some engines, but with my Lehman, at the end of the day I was not able to read the sight tube accurately enough to see how much had been returned to the opposite tank. Maybe a 32nd of an inch? That would be almost 24 ounces. About $1 worth of diesel in an 8 hour run (basically a rounding error). When the fuel flow monitor said that I had burned 11.2 gallons, it would really only be 11 gallons. Big deal.

But my purpose for the fuel monitor is to find the sweet spot not the total fuel burn (although it would likely be as accurate as I would ever need). I am assuming that the tiny injector pump return amount is lineal, meaning that if the injector pump returns 2 drops per minute at 800 rpm, it returns 4 drops per minute at 1,600. Thus, as to finding the sweet spot, or even computing usage per hour, my graph would be sufficiently accurate with no need to keep the fuel flow sender in the system. I could remove the sender and put my $50 fuel monitoring system back in the garage. Then I could spend the $1K-3K savings on diesel. A year's free cruising.

It seems that once the fuel flow rate is graphed, every instant looking at a fuel flow gauge is wasted time. Better to look at the radar screen, oil pressure gauge, or heading.

If anyone is still interested, this project was a success, and I have fuel flow data from both engines now going to my chartplotter.
After over 2 years of refitting this boat, finally had a chance to take her out for a real trip to Annapolis, MD. So far, 130 miles which is 100 more than she travelled in the last 15 years.

Here are a couple of screenshots from yesterday's trip





Consumption data is the total for both engines. I had to adjust the settings in Simrad so it knows there are 2 engines and assign the data from each Delta unit to each engine.

Here is the photo of the installation in the engine room:





I did not find where to change the units from L/h to G/h or NM/gal so had to do a conversion

Nice

As a newb and likely thinking about all of the wrong things, I have been looking for a solution to this problem from my desk. I am going to add this the list of boat projects for the boat I don't have yet

Thanks for sharing all of you hard work.