For any other general hardware. Can be OEM parts (Eg Coils, injectors etc) or anything more specific.
#35431
Hi,

I have made several ignitions for my Panhard cars, using a bespoke PCB fitted with an Allegro Hall sensor potted in a 3D printed case to suit the distributor variants. This just senses the cam lobe proximity, and is phased to work with the rotor arm and distributor cap, an OEM 3Ω ignition coil, or a wasted spark twin ended coil of similar impedance, and is just a points replacement system using a Gotronics control module.

I have also interfaced this same sensor with another custom PCB which works in conjunction with a dwell controlling Bosch Ignition Module, and produces a very healthy spark, jumping 40-50mm in free air, and in testing driving out & about, the ignition has been flawless in wasted spark mode using a Valeo 245129 Renault Megane dry coil.
IMG_9876.jpg
IMG_9876.jpg (258.79 KiB) Viewed 14569 times
I am about to resurrect the Speeduino again, and this time using the sensor with a missing tooth wheel, but I'd like to keep the same wasted spark set up, and dwell controlled Bosch Ignition Module, and trigger it with the Speeduino. The sensor output can be reversed with my PCB to provide a 5V square wave, so feeding this into the Speeduino is no issue for the tooth signals, but my question is can the Bosch Ignition still do the dwell control, which normally expects you to over saturate the ignition for it to work? I don't see any options to disable Speeduino dwell control, and even though I did read the Wiki, my conclusion was I need to set the dwell to a higher value, higher than the coil needs to make sure the Bosch ignition Module does its job.

I also realise I can change the module for a driver type, and let Speeduino do the dwell control, as that's what I'd normally do with MicroSquirts, IMFsofts, and others, but in this case, I'd like to do a back to back and just use the Speeduino as an ignition only device to create a remapped ignition for this engine.

Sorry, if I'm being thick and this has been asked before.
Mike
#35446
"Smart" modules such as this, the GM HEI, Ford DS, etc, are usually current-limiting in their control, holding current at at predetermined level after the coil is saturated and until the spark discharge. In doing this they dissipate the excess energy as heat. This function is only intended to prevent damage by over-dwell heat in systems that provide unlimited current for strong spark, but cannot control dwell duration. Similar to older (but nearly identical dwell-function) points systems which use a current limiter such as a fixed-value ballast resistor, which also protect, but then limit current and spark energy at higher rpm. These are primarily distributor systems with fixed-angle dwell as-opposed to variable duration dwell timing such as Speeduino. A smart module then, is simply a protection system for systems that cannot provide proper dwell time control, especially when dwell would be excessive such as idle and lower rpm, or key on engine off (KOEO).

That said, you can control a module of this type like any other coil driver, providing a dwell start and end (firing) time, and if you over-dwell it will enter limiting. Or you can dwell it spot-on, so it doesn't quite make it into limiting, yet provides maximum coil energy. So, you can see that control by Speeduino can be anywhere from perfect set dwell to a bit too much and it will work as-intended in the current-limiting protection mode. Effectively, you can ignore the protection mode is there and set dwell timing as is normal for any driver, or even too much and it will protect; though we wouldn't want to push it into protection mode across the entire operating range if avoidable. It wasn't designed to handle that. ;) I hope that helps in employing the concepts.

David
#35453
@PSIG aka David, thanks for the clarity, I'd sort of like to keep the Bosch Module, as it simplifies the upgrade path, and I now totally get what your saying and how it'll pan out. I only intended to use this in wasted spark mode, as I would have used different coils and "drivers" from the Bosch parts bin for sequential.

I shall test, using the speeduino, and use the dwell control dialogs built into TS, and do back to back tests. If I get something like this over 25mm, it'll be good enough :)

https://youtu.be/_ibBMFj_V5I

Mike
#35455
Cool, Mike. Go for it. You can see from the concepts that neither Speeduino or the module limit or enhance coil performance when set properly, i.e., it will spark just as well with Speeduino dwell control through the module as it did with stock current-limiting, while reducing the current-limiting work the module did before. Function for that module is current-limiting protection only if it is forced to do so.
8-)
David

{EDIT] In-fact, if you have an oscilloscope, you can use your module to set a perfect dwell correction table at that module's current limit and any voltage. :mrgreen: Just 'scope for how long it dwells before hitting current-limiting, and bingo, that's the perfect dwell at that current and voltage. So, if you read it's at 13.1V and it goes 2.46ms before current limiting, then your corrections at 13.1V and 100% would be 2.5ms. Sure, it would clip current for 0.04ms. :roll: Change the voltage and do it again for another correction point. Slick.

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