Matronics Email Lists :: View topic

Matronics Email Lists
Web Forum Interface to the Matronics Email Lists

Get Email Distribution Too! FAQ Search Memberlist Usergroups Register

Profile Log in to check your private messages Log in

EFII System32

Matronics Email Lists Forum Index -> AeroElectric-List

View previous topic :: View next topic

Author Message

cluros(at)gmail.com
Guest

Posted: Wed Nov 10, 2021 2:37 pm Post subject: EFII System32

In a belated attempt to not derail Michael's electrical system thread, I'm starting this one to ask Charlie for more details on the possible problems with EFII's System32 fuel injection and ignition system when the electrical system architecture is based on the EFII Bus Manager.



I have been hired to test fly an aircraft with this system. Haven't been able to get off the ground yet due to multiple setup problems and wiring mistakes but none of these were related to the Bus Manager.

Charlie I would be very interested to hear anything you have to say FMEA wise about this system.

- The Matronics AeroElectric-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?AeroElectric-List

Ceengland

Joined: 11 Oct 2020
Posts: 379
Location: MS

Posted: Wed Nov 10, 2021 5:40 pm Post subject: EFII System32

On 11/10/2021 4:35 PM, Sebastien wrote:

 	  Quote: 	
		   In a belated attempt to not derail Michael's electrical system thread, 

 I'm starting this one to ask Charlie for more details on the possible 

 problems with EFII's System32 fuel injection and ignition system when 

 the electrical system architecture is based on the EFII Bus Manager.



 I have been hired to test fly an aircraft with this system. Haven't 

 been able to get off the ground yet due to multiple setup problems and 

 wiring mistakes but none of these were related to the Bus Manager.



 Charlie I would be very interested to hear anything you have to say 

 FMEA wise about this system.

OK, for a start, here's a marked up copy of that page from the install 
	


manual. I've likely overlooked some stuff in the quick run-through I 

did, and could be more accurate with an internal schematic + board 

layout of the Bus Manager. But I've marked six ways the system can kill 

the engine, and highlighted a seventh *possible* way; I'd want to see 

exactly how up to twelve fusible links are installed within the 

backshell of the BM connector. Fusible links may or may not generate 

enough heat to be a factor in any wire near them. They're typically 

thermally insulated to protect other wires around them but they're 

typically not tightly confined in an enclosure (the backshell, in this 

case).



As I said, it's difficult to completely evaluate the system without the 

BM info. The drawing shows an external 'daisy chain' connection path 

(circled in red) to the various components, but the yellow circled text 

seems to indicate that path is inside the BM. Having said that, things 

like the ECU select switch are likely to be external.



Hope that's at least some food for thought, and maybe others will have 

some input, as well.



Charlie



-- 

This email has been checked for viruses by Avast antivirus software.

https://www.avast.com/antivirus

- The Matronics AeroElectric-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?AeroElectric-List

sys32.jpg

Description:

Filesize:

266.34 KB

Viewed:

1357 Time(s)

_________________
Charlie

cluros(at)gmail.com
Guest

Posted: Thu Nov 11, 2021 7:28 pm Post subject: EFII System32

Thank you Charlie,

1. What is the failure mode of the relay that could kill the engine?

2. You mentioned DPDT switches can fail to both shorted, is this something that happens when you flip the switch or can the switch just be sitting there and fail?

Thank you,

Sebastien

On Wed, Nov 10, 2021 at 5:44 PM Charlie England <ceengland7(at)gmail.com (ceengland7(at)gmail.com)> wrote:

 	  Quote: 	
		  On 11/10/2021 4:35 PM, Sebastien wrote:

 > In a belated attempt to not derail Michael's electrical system thread, 

 > I'm starting this one to ask Charlie for more details on the possible 

 > problems with EFII's System32 fuel injection and ignition system when 

 > the electrical system architecture is based on the EFII Bus Manager.

 >

 > I have been hired to test fly an aircraft with this system. Haven't 

 > been able to get off the ground yet due to multiple setup problems and 

 > wiring mistakes but none of these were related to the Bus Manager.

 >

 > Charlie I would be very interested to hear anything you have to say 

 > FMEA wise about this system.

 OK, for a start, here's a marked up copy of that page from the install 

 manual. I've likely overlooked some stuff in the quick run-through I 

 did, and could be more accurate with an internal schematic + board 

 layout of the Bus Manager. But I've marked six ways the system can kill 

 the engine, and highlighted a seventh *possible* way; I'd want to see 

 exactly how up to twelve fusible links are installed within the 

 backshell of the BM connector. Fusible links may or may not generate 

 enough heat to be a factor in any wire near them. They're typically 

 thermally insulated to protect other wires around them but they're 

 typically not tightly confined in an enclosure (the backshell, in this 

 case).

 As I said, it's difficult to completely evaluate the system without the 

 BM info. The drawing shows an external 'daisy chain' connection path 

 (circled in red) to the various components, but the yellow circled text 

 seems to indicate that path is inside the BM. Having said that, things 

 like the ECU select switch are likely to be external.

 Hope that's at least some food for thought, and maybe others will have 

 some input, as well.

 Charlie

 -- 

 This email has been checked for viruses by Avast antivirus software.

 https://www.avast.com/antivirus

- The Matronics AeroElectric-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?AeroElectric-List

nuckolls.bob(at)aeroelect
Guest

Posted: Wed Nov 17, 2021 9:24 am Post subject: EFII System32

 	  Quote: 	
		   

  OK, for a start, here's a marked up copy of that page from the install 

  manual. I've likely overlooked some stuff in the quick run-through I 

  did, and could be more accurate with an internal schematic + board 

  layout of the Bus Manager. But I've marked six ways the system can kill 

  the engine, and highlighted a seventh *possible* way; I'd want to see 

  exactly how up to twelve fusible links are installed within the 

  backshell of the BM connector. Fusible links may or may not generate 

  enough heat to be a factor in any wire near them. They're typically 

  thermally insulated to protect other wires around them but they're 

  typically not tightly confined in an enclosure (the backshell, in this 

  case). 	
 

   Fusible links are NOT replacements for fuses.



   Fusible links are ROBUST protection against

   hard faults and are used in power distribution

   feeders like alternator b-leads, extension feeders

   between busses, some battery installations, etc.



   They are RARELY suited for protection of

   individual loads.



   What is the rational for protecting these

   feeders individually in the first place?

   Manufacturer's recommendations? Consider

   REAL fuses if a FMEA warrants such protection.



 

 

   Bob . . .



   Un impeachable logic: George Carlin asked, "If black boxes

   survive crashes, why don't they make the whole airplane

   out of that stuff?"

- The Matronics AeroElectric-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?AeroElectric-List

Ceengland

Joined: 11 Oct 2020
Posts: 379
Location: MS

Posted: Wed Nov 17, 2021 2:36 pm Post subject: EFII System32

On Wed, Nov 17, 2021 at 11:28 AM Robert L. Nuckolls, III <nuckolls.bob(at)aeroelectric.com (nuckolls.bob(at)aeroelectric.com)> wrote:



 	  Quote: 	
		     	  Quote: 	
		   

  OK, for a start, here's a marked up copy of that page from the install 

  manual. I've likely overlooked some stuff in the quick run-through I 

  did, and could be more accurate with an internal schematic + board 

  layout of the Bus Manager. But I've marked six ways the system can kill 

  the engine, and highlighted a seventh *possible* way; I'd want to see 

  exactly how up to twelve fusible links are installed within the 

  backshell of the BM connector. Fusible links may or may not generate 

  enough heat to be a factor in any wire near them. They're typically 

  thermally insulated to protect other wires around them but they're 

  typically not tightly confined in an enclosure (the backshell, in this 

  case). 	
 

   Fusible links are NOT replacements for fuses.



   Fusible links are ROBUST protection against

   hard faults and are used in power distribution

   feeders like alternator b-leads, extension feeders

   between busses, some battery installations, etc.



   They are RARELY suited for protection of

   individual loads.



   What is the rational for protecting these

   feeders individually in the first place?

   Manufacturer's recommendations? Consider

   REAL fuses if a FMEA warrants such protection.



 

 

   Bob . . .

	
I'll take another swing, since I wrote the quoted text (it should be obvious from the text that I don't care for the actual product being discussed).

My yet-to-fly EFI (NOT FlyEFII) has separate fuses for each injector and each coil. The reason I did it is that it's dirt simple to do, weighs only a few ounces, and isolates each item from all the rest in case of a failure. No doubt that's why FlyEFII used individual fusible links, too.

Logic: If running a carb, you can't isolate fuel delivery to each cylinder; you're stuck with one delivery point. Not much difference with 'traditional' a/c fuel injection. But with electronic injection and dual controllers, it's relatively easy to isolate the feed to each device so that a failure along one path will not cause the entire system to go down. That kind of issue is what I was trying to describe in the marked-up version of the wiring diagram; eliminating points where a single failure takes the entire system (in this case, the engine) offline. I consider being able to effectively isolate each cylinder (or pair of cylinders, with some coils) to be a significant advantage with electronic injection over traditional systems. (I do recognize that the added installation complexity can be a negative factor.)

As to the fusible link vs fuse question: I used links in several (all?) the places you mention, for the same reasons; they're as reliable as the wire itself, fewer mechanical joints, and the only reason they would ever need to act is in a catastrophic fault situation. While I haven't installed them for my injectors & coils, I can see justification for using them there, for the same reasons. One shorted coil or one shorted injector will almost certainly burn itself open before either its fuse or, if used, a fusible link would activate. So the only reason for branch protection is the catastrophic failure mode of a shorted wire. Using the links reduces the number of mechanical joints (transitions) in the path to the device. 

FWIW,

Charlie

- The Matronics AeroElectric-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?AeroElectric-List

_________________
Charlie

nuckolls.bob(at)aeroelect
Guest

Posted: Wed Nov 17, 2021 3:02 pm Post subject: EFII System32

 	  Quote: 	
		   

  I'll take another swing, since I wrote the quoted text (it should be obvious from the text that I don't care for the actual product being discussed).



 My yet-to-fly EFI (NOT FlyEFII) has separate fuses for each injector and each coil. The reason I did it is that it's dirt simple to do, weighs only a few ounces, and isolates each item from all the rest in case of a failure. No doubt that's why FlyEFII used individual fusible links, too. 	


    Okay, if that's what the mfgr wants. But generally

    speaking, fusible links are in the same class of

    protection as the ANL current limiters. They take

    10x longer to open under same 'rated' loads  . . .

    and make smoke.



    Also watch for situations where one fusible

    link is supplied from another fusible link

    upstream. You have a I(squared)R timing

    dynamic to consider for series connected

    circuit protection.



 

 

   Bob . . .



   Un impeachable logic: George Carlin asked, "If black boxes

   survive crashes, why don't they make the whole airplane

   out of that stuff?"

- The Matronics AeroElectric-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?AeroElectric-List

Display posts from previous:

	Matronics Email Lists Forum Index -> AeroElectric-List	All times are GMT - 8 Hours
Page 1 of 1

Jump to:

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum