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Methanol Injection Flow Safety


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Hi Guys,

        Is it possible to add some sort of Methanol Injection flow Safety? Two 3d tables would be required as you would need a low flow safety as well as a high flow safety to cover all bases. As an alternative, a single table with an expected value then a single percentage out of range setting. That would save a table. This would then be able to apply a boost target trim if flow fell out of this range. A methanol flow rate input would be nice as well with a CC/Min unit. This would allow use of methanol injection completely controlled by the Link ECU. Im sure there are ways to make this even more elegant however this gives a general idea.

 

Blaine Carmena

Carmena Performance

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I'm curious to hear what the logic is behind this request?  I only have involvement with a couple of high powered methanol drag cars so don't have a large pool of experience to draw from but why would you expect a methanol fuel system to be any less reliable than a petrol system?  Maybe the mechanical pump?  If that is the case why not just use differential fuel pressure as a GP limit?  Fuel flow sensors are relatively expensive and I think it is a variable that would be pretty difficult to nail down tight enough to make it useful as an effective safety. i.e, functions like RPM limit, gear cut, warm up corrections etc are all going to throw many more dimensions into the equation on what you need to consider to arrive at expected fuel flow.

I would have thought Lambda and dif fuel pressure would have been a better way to monitor the fuel system  (although in my experience Lambda based safetys aren't particularly useful either it would be more consistent than fuel flow).

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Hi Adam,

I believe Blaine is talking about a water/methanol injection kit, like the AEM one. I saw a webinar the other day where the AEM controller has a setup like Blaine described. It basically means if you run out of water/meth mix or have a pump or plumbing issue the ECU would be able to reduce boost to protect the engine from detonation.

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I believe Blaine is talking about a water/methanol injection kit, like the AEM one. I saw a webinar the other day where the AEM controller has a setup like Blaine described. It basically means if you run out of water/meth mix or have a pump or plumbing issue the ECU would be able to reduce boost to protect the engine from detonation.

Oh yeah, reading it again you are probably right.  You are obviously a better mind reader than me...

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That 

Hi Adam,

I believe Blaine is talking about a water/methanol injection kit, like the AEM one. I saw a webinar the other day where the AEM controller has a setup like Blaine described. It basically means if you run out of water/meth mix or have a pump or plumbing issue the ECU would be able to reduce boost to protect the engine from detonation.

That is exactly what I was thinking Scott. Sorry, I should have been more clear. Many of the kits use quick disconnect fittings that once removed once are prone to blowing off. Not good if the engine is tuned for the Water/Methanol.

Blaine

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If I  got it right, the only way to control water methanol by LINK ECU (without external controller) is to use the IC Spray function.

But the IC Spray funktion can only be set to a duty cycle of 95%. Would be nice it could be set to 100%

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There are a number of ways you could do the water/meth injection using a G4+ ECU, depending on how advanced you want to get. For most installations I think using the GP PWM function would be best.

This gives you:

  • up to 3 switch on conditions
  • a 3D table on which you can specify two variables as control over the duty cycle (0 to 100%)
  • a 3D frequency table to vary frequency of injection based upon two other variables.

However I still like Blaines suggestion of a safety table. 

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There are a number of ways you could do the water/meth injection using a G4+ ECU, depending on how advanced you want to get. For most installations I think using the GP PWM function would be best.

This gives you:

  • up to 3 switch on conditions
  • a 3D table on which you can specify two variables as control over the duty cycle (0 to 100%)
  • a 3D frequency table to vary frequency of injection based upon two other variables.

However I still like Blaines suggestion of a safety table. 

got it...  thats nice

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There are a number of ways you could do the water/meth injection using a G4+ ECU, depending on how advanced you want to get. For most installations I think using the GP PWM function would be best.

This gives you:

  • up to 3 switch on conditions
  • a 3D table on which you can specify two variables as control over the duty cycle (0 to 100%)
  • a 3D frequency table to vary frequency of injection based upon two other variables.

However I still like Blaines suggestion of a safety table. 

This was my intent. I would prefer to use an external controller until I have a safety though. At least some of the aftermarket controllers have safeties for motor shorts and opens. With a safety table in the link it wouldnt matter what failure it had as it would be picked up by the flow range.

Blaine

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  • 10 months later...

Hi Plox, I think we might be able to do it with a combination of the functions that are already available.  Can you tell me the conditions/inputs that you want to control the pump and also what actions you want the ecu to take when the pump is on and flow sensor reads lower than expected. I will see if I can dream up a way to achieve it.

Also, what is the output signal type and range for the flow sensor.

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Thanks for the quick reply, sorry about the following novel.

Rough diagram attached, Current thoughts are: On/off switch turns the whole water meth system on - pump on, and switches fuel, timing and boost maps (either 4/5d, overlay or dual maps). The (recirculation) pump primes when the on/off switch is turned on, then turns on over Xkpa 100?. Solenoid is active over 100kpa but duty is 0 until 120kpa, then based on IDC vs Map (I've calculated a table based on wanting 20% of 50/50 mix compared to fuel amount).

Sensor is: 0.25-2.5L/Min Hall Effect Water Flow Sensor

Flow Range    0.25-2.5L/Min 
Working Voltage & Current    DC 3V-18V, 10mA
Rated Voltage    DC 5V
Pulse Duty Factor    50 %
High Level of Pulse Output    >4.5V
Low Level of Pulse Output    <0.5V

 

I've calibrated the sensor to g/s based on water mass. Unfortunately if the sensor doesn't actually read below 0.25l/min (roughly 4g/s) it won't read anything until roughly 35-40% IDC (5000rpm,200kpa ish), But if it gets to 40% IDC and there is no flow detected then I want it to switch the maps back, rpm cut or similar.

Is a possibility 4d/5d map based on the flow? therefore if no flow the map doesn't change. Issues being the high reading sensor, and boost map isn't switched via flow (but could be via virtual aux?)

I'm open to adding a pressure sensor or other suggestions too.

Capture.JPG

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  • 4 years later...

Wonder if this feature (max and min tables) was ever added to the G4+ software, or there was an alternative solution found?

Also have a hall effect flow sensor for water methanol injection that would be good to set up as a safety. Otherwise is the best solution still an external controller?

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ECU is a G4+ Thunder.

I'd like a way of reading the hall effect output of the flow sensor so that it can be compared to the commanded PWM output to the water methanol solenoid. This controls the flow of water methanol through the system so there should be a relationship between these parameters.

If the range of values from the hall effect sensor falls within an acceptable range (ie system flow is appropriate for commanded solenoid PWM value) then all is good, but if not, it will trigger a failsafe condition and switch back to standard fuel and ignition maps. 

Fot reference, the water methanol system I'm referring to is an Aquamist HFS3. 

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I cant think of any way of achieving that in G4+. 

The best you could do would be a couple of validation based conditions such as for example between 100-200kpa MAP minimum flow must be 200cc/m, and above 200kpa MAP the minimum flow must be above 300cc.

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