Fuel Flow Metering/Consumption

[LIboater]

Hi all,

I have several questions that I hope some of you can help me with.

First off, I have a 2002 SR 340 Sundancer with two 8.1 Horizons. I have 2 fuel tanks with no cross-over between them.

It seems that my port engine uses slightly more fuel than starboard. Both engines were tuned at beginning of season and mechanic reported no particular issues.

Last summer I installed a new Raymarine a9 series MFD and i70s display.


My first set of questions deals with getting engine data to the Raymarine displays.
1) The most critical data I want is fuel consumption (rate of over time). I was told that the engine computers will provide this data, but it is based on a calculation of RPM and not really fuel flow. Is this correct? Or, does the engine have a metering device that senses actual fuel flow to all cylinders?

2) My Raymarine electronics are NEAM 2000 network. What protocol do the engine's computers talk? What do I need to convert to NEMA 2000?

3) My other option is to get installed a Maretron FFM100 system with actual flow meters spliced into fuel lines. Is this what I need to get reliable fuel consumption data?

My next set of questions are about the fuel supply system itself.
1) I have 2 fuel tanks each supplying their respective engines. I noticed that from the tanks the lines go into Parker brand "Skinner Valves". What do these valves do?
2) Also each valve has a small knob with a stamped arrow that is set differently.
On the Starboard side the knob arrow points to "ON" see picture.

On the Port side the knob arrow points to "OFF".


Which one should it be? ON or OFF? And could this affect fuel consumption?

Thanks for your help

[Captsteve53]

OK, LAST QUESTION FIRST: as rushing out the door,

The Skinner Valves are safety solenoids hooked up to your ignition system so will activate (Open) when you turn the Ignition and more importantly (close) when shut the engine down (Fire safety),

The normal position should be CLOSED, some people turn to open if the circuit has failed or the valve it's self has failed (basically an emergency get home system), should not make any real difference to fuel usage if working correctly,

Answer some more later

Cheers Steve

[aclmck]

Originally Posted by LIboater

Hi all,

I have several questions that I hope some of you can help me with.

First off, I have a 2002 SR 340 Sundancer with two 8.1 Horizons. I have 2 fuel tanks with no cross-over between them.

It seems that my port engine uses slightly more fuel than starboard. Both engines were tuned at beginning of season and mechanic reported no particular issues.

Last summer I installed a new Raymarine a9 series MFD and i70s display.


My first set of questions deals with getting engine data to the Raymarine displays.
1) The most critical data I want is fuel consumption (rate of over time). I was told that the engine computers will provide this data, but it is based on a calculation of RPM and not really fuel flow. Is this correct? Or, does the engine have a metering device that senses actual fuel flow to all cylinders?

2) My Raymarine electronics are NEAM 2000 network. What protocol do the engine's computers talk? What do I need to convert to NEMA 2000?

3) My other option is to get installed a Maretron FFM100 system with actual flow meters spliced into fuel lines. Is this what I need to get reliable fuel consumption data?

My next set of questions are about the fuel supply system itself.
1) I have 2 fuel tanks each supplying their respective engines. I noticed that from the tanks the lines go into Parker brand "Skinner Valves". What do these valves do?
2) Also each valve has a small knob with a stamped arrow that is set differently.
On the Starboard side the knob arrow points to "ON" see picture.

On the Port side the knob arrow points to "OFF".


Which one should it be? ON or OFF? And could this affect fuel consumption?

Thanks for your help

I had an issue on some 90hp Honda outboards and had to install flow meters in each line this were run through a Garmin machine which worked extremely well, we could actually check the fuel consumption at varying RPM"S/knots etc all very accurate , we could adjust speed to the best consumption possible for the sea state. so it is possible to do what you want even if the motors are not nema compliant, (most smaller outboards are not compliant)

Sorry but I can't help with the rest of your questions

[Captsteve53]

OK, Most modern electronic engines use CAN BUS(Controller Area Network)it is a robust vehicle bus standard designed to allow micro-controllers and devices to communicate with each other in applications without a host computer. It is a message-based protocol, designed originally for multiplex electrical wiring within automobiles to save on copper, but is also used in many other contexts.

You will need a Can bus conversion data module to talk to your NMEA instruments, Ray marine have there own as whole system as Quote:

A simple isolated CAN Bus solution, the ECI-100 offers reliable integration with Raymarine's latest generation of multi-function displays and also delivers a seamless autopilot steering interface to Raymarine's Evolution EV-2 Drive-by-Wire autopilot system.
Found here: ECI-100 Universal Engine and Control Interface

But third party modules are available which should and display on your present set with those available limits:

,RS11 - CANbus Engine Data Converter, NoLand Engineering

https://www.maretron.com/products/j2k100.php

http://www.furunousa.com/ProductDocu...k%20Design.pdf



How ever the above Ray-marine system basically displays every thing from Engine to Gear box

Cheers Steve

[Captsteve53]

Regarding your fuel flow Question:

1)The fuel level sensor and/or dаta, derived from the CAN bus of a vehicle can be used.
2)How ever Fuel flow meters are usually very accurate – around 1% max inaccuracy, calculating both inflow and outflow from the engine and so detecting actual consumption in each particular moment;
3) Fuel level sensors capable of calculation general fuel consumption over longer periods of time, as they calculate consumption by indirect method and so giving inaccuracy around 5%;
4)Connection to the standard sensors via CAN bus is easy and quick, but gives only overall image of consumption, as standard sensors on vehicles are at least 10-15% inaccurate.

There fore if you are looking for accuracy a separate system is normally used and the sky is the limit on the complexity of the system as:

Fuel flow meter | Wagencontrol: fuel monitoring for GPS tracking systems

https://parts.cat.com/wcs-static/pdfs/PEHJ0429-00.pdf

Boat Fuel Flow Meter System from WMJ Marine


Cheers Steve