Dual fuel support

Testing and development of Megasquirt 3

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jsmcortina
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Dual fuel support

Post by jsmcortina »

What support would people like? and how best implemented?

Two main categories I'm thinking of here:
a. LPG conversions

Fuel table switching is easy here, but what about different injector characteristics?
How about using a different set of outputs? (i.e. on a 4 cylinder you could use all 8 injector outputs on the MS3X board - 4 for petrol and 4 for lpg.)
Is a different ReqFuel required?

b. 100% Methanol for racing
Swap from petrol to Methanol (same issues as a) or staged?
Different injector outputs?

EDIT:
c. Flex fuel.
This already has some support in the code using a flex-fuel sensor.

thoughts?

James
I can repair or upgrade Megasquirts in UK. http://www.jamesmurrayengineering.co.uk

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UnaClocker
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Re: Dual fuel support

Post by UnaClocker »

Are we talking FFV support? I'd like to see the FFV support get developed further. As it is, it simply adjusts the fuel tables a bit. I'd like to see it adjust the spark tables and the boost tables as well. Some kind of user definable amount, I think about .75 degrees more timing per 10% of ethanol might be a good baseline. And then maybe a second boost target table that gets switched to below a certain ethanol concentration.. I'm not sure how fast those FFV sensors come online, but since we can't store things from start to start without flashing it, I don't know if the FFV mode could adjust the priming PW and cranking PW numbers. It'd sure be nice if there were some way of doing it..
Brian
'84 Dodge Rampage
Paul_VR6
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Re: Dual fuel support

Post by Paul_VR6 »

I'm planning on running E85 once I upsize the inejctors a bit. Don't really want to drive on it so FFV on table switch would be good. Basically be able to scale *everything* and the change tables.

Not sure if there's a good/cheap/available flex fuel sensor yet.
-Paul
1992 Corrado SLC 3.6 VR6 11.38@120 - MS3 Pro Ultimate - Microsquirt I/O - Can EGT - Racepak IQ3s
kptuned.com - Megasquirting the World! Megasquirt Sales, Service, Tuning and More!
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Mustang68

Re: Dual fuel support

Post by Mustang68 »

a. LPG conversions

Fuel table switching is easy here, but what about different injector characteristics?
How about using a different set of outputs? (i.e. on a 4 cylinder you could use all 8 injector outputs on the MS3X board - 4 for petrol and 4 for lpg.)
Is a different ReqFuel required?
Todo lpg and petrol both 100% right you should have almost every fuelsetting switchable.
- cold start petrol enrichment, lpg no wall wetting + cold lpgvapor you have to inject less lpg wen cold
- the accel enrichments should be different again no wetting of the manifold

I setup my car to run mainly to run on lpg. I use Jeans alpha seq code and dual MS daugther boards todo fullseq injection on my V8 this works very nice on lpg for my intake with short runners. I'm injecting went the intake valve opens so i dont have problems with one cil sucking lpg form one of the other cil.

The injector are both wired to the same drivers and i switch between them. The difference in opening time are added in the ve table 1ms for petrol, 3ms for lpg.

Also lpgvapor temp correction would be nice (im using the matsensor input for that now)+ lpgvapor pressure corr.

Jacco
jsmcortina
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Re: Dual fuel support

Post by jsmcortina »

I guess flex fuel is a special case because it is all in the same fuel tank and the mixture changes. Perhaps in flex fuel mode we could run the pump a bit longer and sample the flex senser during that period for cranking parameters?
Ideas welcome.

I was _mainly_ thinking about two totally different fuel systems here, I'll edit the first post to add Flex.

On the LPG, any information on the correction calculations required?
How would you typically wire the injectors?
1. All together with a relay switch
2. Petrol bank1 and LPG bank2 and a software switch
3. (in the future) with the own sequential channel and a software switch?

James
I can repair or upgrade Megasquirts in UK. http://www.jamesmurrayengineering.co.uk

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jabran200
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Re: Dual fuel support

Post by jabran200 »

I am really interested in this.

If I could use the same ecu with switch the injectors outputs only on a 4 cylinder this would be my brilliant.

How would the mappign work? Could I map it on petrol and use the same map with the corrections for lpg and then fine tune the lpg map?

Would totally reduce the need for having a slave lpg ecu.

I am waiting in anticipation lol.
jabran200
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Re: Dual fuel support

Post by jabran200 »

A few things that would really make the lpg sytem usable,

-Additional input for a temp sensor for lpg temp correction
-On board or external map sensor for lpg pressure correction

There are other things that would be useful but I think those two are really the main ones.
These would be a good add on.

Switch fuel pump off when lpg is on?
jabran200
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Re: Dual fuel support

Post by jabran200 »

I have a query, Would it be possible to have 4 petrol injectors and 8 lpg injectors on the other 4 outputs? I say this because high capacity lpg injectors are hard to find and are expensive. The petrol injectors are high impedance and the lpg injectors are 3 ohm.

I.e petrol
1-cyl 1
2-cyl 2
3-cyl 3
4- cyl 4

lpg
5 - cyl 1 inj 1+2
6- cyl 2 inj 3+4
7- cyl 3 inj 5+6
8 - cyl 4 inj 7+8

Interested in this.
jsmcortina
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Re: Dual fuel support

Post by jsmcortina »

Due to the transistor outputs on the MS3X board it would probably work better to have the four petrol injectors on the MS3X like you say, but run the 8 LPG injectors as two banks of four from the two V3 Mainboard injector channels as these can more readily support multiple low-z injectors.

James
I can repair or upgrade Megasquirts in UK. http://www.jamesmurrayengineering.co.uk

My Success story: http://www.msextra.com/forums/viewtopic ... 04&t=34277
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New users, please read the "Forum Help Page".
ca434sbc4
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Re: Dual fuel support

Post by ca434sbc4 »

jsmcortina wrote:Due to the transistor outputs on the MS3X board it would probably work better to have the four petrol injectors on the MS3X like you say, but run the 8 LPG injectors as two banks of four from the two V3 Mainboard injector channels as these can more readily support multiple low-z injectors.

James
James

Could the V3 main board injector channels be mapped in s/w to the second fuel table with an external logic input/map setting to enable? Think #2 in your first post - switch to 100% alky when externally enabled and map is > threshold.

Thanks
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