Ion Sense

Hardware inside and outside of the ECU
Simon@FutureProof
contributor
contributor
Posts: 413
Joined: Tue Jul 24, 2018 8:55 pm
Github Username: Orchardperformance
Slack: Orchardperformance

Re: Ion Sense

Post by Simon@FutureProof »

So there's a couple of things here, your absolutely correct the spark discharge is a problem, the ion sense is essentially blind during the discharge which makes things difficult but not impossible.

I don't want to give away too much detail at this stage but we have found a way to determine the transition from spark to flame that allows us to get a better understanding of the ignition delay and remove a lot of that problem.

As Matt notes, I have managed to do some work with the SAAB conventional coils and their CDM module, they have given some pretty solid data and it's looking like we may be able to actually achieve accurate detection on a running engine relatively soon.
Now keeping MRE in stock in the UK - https://www.FutureProofPerformance.com
User avatar
sepp2gl
Posts: 34
Joined: Sat Jan 01, 2022 3:47 pm
Location: Germany
Github Username: sepp2gl

Re: Ion Sense

Post by sepp2gl »

@mck1117:
mck1117 wrote:
Sat Jan 01, 2022 7:56 pm
As far we I know, Mazda is doing both of these on their Skyactiv engines.
I will double-check Mazda's Skyactiv system, why they are using IS and which specific functions are inplemented.
mck1117 wrote:
Sat Jan 01, 2022 7:56 pm
We're most interested in #1.
mck1117 wrote:
Sat Jan 01, 2022 7:56 pm
This isn't too big a problem, since there isn't much overlap between the spark and the time we care about sensing cylinder pressure. There are also ways to force a quench of the spark (short out the coil primary) when you know you've delivered enough energy to the spark and want to start sensing now.
How do you find out, if sufficient spark-energy gas been provided?

mck1117 wrote:
Sat Jan 01, 2022 7:56 pm
Saab had two different systems: one using the "cartridge" which was CDI, and one using things that look like normal coil-on-plug with an external module. The normal coil looking ones are not CDI, and are very similar (down to the pinout and coil connector) to the currently sold ones on Mazda Skyactiv.
Yes I know, they used Melco-Coils in the later years.
mck1117 wrote:
Sat Jan 01, 2022 7:56 pm
sepp2gl wrote:
Sat Jan 01, 2022 7:37 pm
Having said that, I would not declare it to be technically impossible. But it might be rocket-science for a hobbyist.
Our preliminary testing has shown very promising results :)
[/quote]
This statement was related to daveblanchard's project, not in general.

In general, combustion phasing using IS is highly challenging esp. at low engine loads, where the thermal ionisation is very low, at the same time the signal is pretty noisy so really locating location of maximum ionisation by means of software can give you some hard times.

@OrchardPerformance:
If a CDI can fulfill all requirements for engine operating points, it can be an enabler for IS technology.

Concerning ignition delay, the most influencing factor might be a high turbulence in the combustion chamber.
But all this highly depends on the combustion system and engine concept.

looking forward to some interesting exchange
T2US, sepp2gl
Everything keeps being better ... ;)
bill
Posts: 219
Joined: Sun Mar 29, 2020 1:44 pm
Location: DC usa

Re: Ion Sense

Post by bill »

sepp2gl wrote:
Sat Jan 01, 2022 9:21 pm

Yes I know, they used Melco-Coils in the later years.

looking forward to some interesting exchange
T2US, sepp2gl
Welcome Aboard!
Looking forward to your help ....
bill
User avatar
sepp2gl
Posts: 34
Joined: Sat Jan 01, 2022 3:47 pm
Location: Germany
Github Username: sepp2gl

Re: Ion Sense

Post by sepp2gl »

...coming back to Mazda's "Skyactiv engines"...
Skyactiv is a brand-name, that stand for a couple of different types of engines with various technologies.
- Skyactiv-G is a gasoline engine with cylinder-deactivation, a very high compression-ration of 14:1 and for that they need to apply a piston with a bowl.
I guess, they use Miller/Atkinson-cycle to adjust CR14:1 at high load operation.
- Skyactiv-X is agasoline engine with homogenious-charge-compression-ignition HCCI for partload operation, which is supported by a spark to avoid
misfire operation under certain part-load condition and generally in high-loads. So you need a spark-plug anyway.
For HCCI-operation the tight control of combustion-phasing is crucial. As the engine runs homogenious-lean and ignition is initiated by pressure and
temperature in the combustion chamber, there are numerous parameters, that affect the activation energy. Consequently they need kind of combustion
feedback, which can be either Ion-Sense or combustion pressure sensors. Ion sense might be lower in cost, if it is "good enough".
Maybe Skyactiv-X also includes Skyactive-G technology for some reason.
One of the most challenging things with HCCI is the mode switch between HCCI in part-load and "normal" spark-ignition in full-load, which must not
degrade driveability (e.g.jerky ride) of the car.
- Skyactiv-D is just their name for their current Diesel technology.

So the name "Skyactiv" as such does no represent a certain engine technology, it is just a brand-spefific name.
T2US, sepp2gl
Everything keeps being better ... ;)
mck1117
running engine in first post
running engine in first post
Posts: 1493
Joined: Mon Jan 30, 2017 2:05 am
Location: Seattle-ish

Re: Ion Sense

Post by mck1117 »

All skyactiv engines with spark plugs have ion sense. I've personally scoped the ion sense line on my Skyactiv-G 2.0 in my ND2 Miata and it looks as expected.
User avatar
sepp2gl
Posts: 34
Joined: Sat Jan 01, 2022 3:47 pm
Location: Germany
Github Username: sepp2gl

Re: Ion Sense

Post by sepp2gl »

Can you tell, what functionality is covered by IS on Skyactive-G?
Is it more basic misfire & knock detection?
Or does Mazda use advanced functions?
Everything keeps being better ... ;)
User avatar
sepp2gl
Posts: 34
Joined: Sat Jan 01, 2022 3:47 pm
Location: Germany
Github Username: sepp2gl

Re: Ion Sense

Post by sepp2gl »

@mck1117:
...any reply? :?: :?: :?:
What do you mean by "...looks as expected"?
What was your expectation?
kr, sepp2gl
Everything keeps being better ... ;)
Simon@FutureProof
contributor
contributor
Posts: 413
Joined: Tue Jul 24, 2018 8:55 pm
Github Username: Orchardperformance
Slack: Orchardperformance

Re: Ion Sense

Post by Simon@FutureProof »

In this case "as expected" would be in regard to the conventional ion sensor systems as used by SAAB etc.
image.png
image.png (47.05 KiB) Viewed 10197 times
Very similar to what we saw here with the SAAB system.

https://github.com/rusefi/rusefi/wiki/Saab-Trionic-8-Combustion-Detection-Module-on-Mazda-Miata-running-rusEFI

The irritating thing with the Mazda coils is we/I was not able to get a decent signal out of them off the car. Still unknown as to the reason why.
Now keeping MRE in stock in the UK - https://www.FutureProofPerformance.com
User avatar
sepp2gl
Posts: 34
Joined: Sat Jan 01, 2022 3:47 pm
Location: Germany
Github Username: sepp2gl

Re: Ion Sense

Post by sepp2gl »

@OrchardPerformance:
Looking to the diagram, the black trace is the typical shape of an ion-sense native signal, with the blue trace being combustion pressure as reference.
It is important to know, that you don't get this perfect shape under all conditions of engine operation: mid/high load operation should be easy, low load or idle conditions I wouldn't rise my hand for it. In any case it is not a trivial task to isolate the characteristic values out of the signal.
Especially with the differentiated signal (magenta), you might get extreme issues with noise.

I went into the GitHub-Link. It is hard to analyse the observed signals, if you do not know any engine operating conditions or signals taken.
At least the yellow trace looks like a native Ion-Sense signal, but heavily disturbed.
As the ion signal is very sensitive, it should be processed with high care to noise cancellation.
Everything keeps being better ... ;)
JohnP
Posts: 1
Joined: Mon Apr 11, 2022 7:23 pm
Location: SoCal

Re: Ion Sense

Post by JohnP »

The ion system for Harley Davidson was made by Delphi, but they went back to knock sensing in 2017.

"...the switch from ion-sensing knock sensors to cylinder-mounted ones dramatically increases the range of individual cylinder spark control the ECU has over the firing of the twin plugs, allowing as much ignition advance as possible. “So, you’re not creating heat by retarding the spark to keep yourself away from knock,” explains Bozmoski.

Since knock increases exhaust gas temperature (EGT) and in extreme cases can damage the engine, the Milwaukee-Eight’s ignition timing can be retarded right up to the point of the first signs of predetonation, which has no sound, and then be walked back until it stops. Managing ignition timing to the ragged edge of detonation delivers not only more power with less heat, but it also burns cleaner for fewer emissions..."

Apparently, HD says knock senors are more sensitive. This is the caption in one of the photos:
"Knock sensors mounted to each cylinder allow for the least amount of ignition retard possible without detonation."

Full article is here:
https://www.motorcycle.com/manufacturer/harley-davidson/2017-harley-davidson-milwaukee-eight-engines-tech-brief.html


Visteon is a Ford spinoff. They published a paper in 2008 on ion sensing for a "large displacement motorcycle engine", and showed their system was more sensitive than knock sensors.

It compares knock and ion sensing to in cylinder pressure sensing, as a reference:
Thinking is hard work
User avatar
sepp2gl
Posts: 34
Joined: Sat Jan 01, 2022 3:47 pm
Location: Germany
Github Username: sepp2gl

Re: Ion Sense

Post by sepp2gl »

@JohnP:
very interesting paper from Visteon.
The findings were mostly well-known state-of-technology.
If you only look at the pure detection of knock-occurrence, there is a lot arguments for ion-sensing.
There are three alternative solutions know: vibration-based (knock sensor), ion-current-based, combustion-pressure based.
They all have their pros and cons to be considered.
But after all it is a commercial decision about which way to go.
As criteria for the decision, there is always
- product-cost on top-priority (at least for mass-production) followed by
- development and investment cost
- technical risk (new, technology is always considered higher risk), good/bad experience/reputation, is the "old" solution sufficiently good or not?
- availability of components (second source available?)
- support by EMS supplier (can be a highly political issue)
- business model (especially the depth of OEM-involvement into EMS-development; Make-or-buy)
- timing, can it be developed on-time for SoP?
There must be good reasons, why there is still knock-sensors as mainstream solutions on the market.

The criteria are differently ranked in importance, depending on if we target for mass production or small-scale production.
So for small-scale we can find different solution selected.
Harley-Davidson might have had good reasons for doing ion-sense and they had good reasons for going vibration-based now.
And of course they found a good advertising strategy to claim "It is better now".

If I was intending to apply knock-detection to my motorbike, I might first consider ion-sense.
Why? First of all it can be easily implemented by just electronics in the ignition coil and the ECU. And I could do it on my own.
There is no need for a special bold on the engine block for the knock-sensor, which needs to be carefully selected to allow equal-quality knock-detection for each cylinder.
And I wouldn't even consider to drill a hole into the cylinder head for the In-cylinder-pressure sensor.

But if I was responsible for a mass-product, I would compare the cost of commodity ignitions-coils, igniters and knock sensors with a special coils, igniters and no knock-sensor.
Everything keeps being better ... ;)
Simon@FutureProof
contributor
contributor
Posts: 413
Joined: Tue Jul 24, 2018 8:55 pm
Github Username: Orchardperformance
Slack: Orchardperformance

Re: Ion Sense

Post by Simon@FutureProof »

It has been my experience that the piezoelectric knock sensors are able to detect the onset of knock sooner than the ion signal simply because the ion signals seem to be insensitive to that early low amplitude knock oscillation.
Now keeping MRE in stock in the UK - https://www.FutureProofPerformance.com
Niklas
Posts: 4
Joined: Fri Jan 26, 2024 6:47 am

Re: Ion Sense

Post by Niklas »

Hello Guys, why do we not use BMW-Ion-Sense Moddule from the V10?

Here some info from TIS.

I think the hardest part of work ist to write the code...

Code: Select all

Ionic current control units MSS65

Functional description, see Vehicle Technology Diagnosis:

110404097
Overview of functions

The DME activates the ignition coils via the ionic current control units. There is an ionic current control unit for each cylinder bank.

The ionic current control units make it possible to monitor each individual combustion and misfire and to detect combustion knock. Here, a distinction can be made by the DME as to whether misfires were caused by a lack of ignition sparks or poor combustion.
Function sequence

Ignition activation:via the signals S_IGZ1-10, the DME controls the final stages for the ignition in the ionic current control units.

    Signal low: charging the ignition coil, 1 ‐1.5 ms
    Signal high: switching the signal to high triggers the ignition spark.

Ionic current measurement:immediately after the end of the ignition sparks, the ionic current control units apply a constant measured voltage to the electrodes of the spark plugs. Here, the ionic current control units receive and amplify the currents that arise (ionic currents).

Via the signals A_ION1 and A_ION2, the ionic current that arises with each combustion is then sent from each ionic current control unit to the DME. The ionic current is 0 -20 mA and is evaluated in the Digital Engine Electronics. This evaluation enables the DME to detect misfires and combustion knocks.

The measured voltage is created in that the spark current that flows during the duration of spark combustion flows into a capacitor in the ionic current control unit. The energy that is stored in the process is applied after the ignition spark as measured voltage to the spark plug electrodes. The ionic current flows in the opposite direction to that of the spark current.

Signal amplification:the Digital Engine Electronics assesses the quality of the incoming ionic current signals and indicates to the ionic current control units via the signals S_IONV1 and S_IONV2 the extent to which the ionic current signals have to be amplified. The amplification factor ranges from 1‐5.

Measurement voltage selection:the Digital Engine Electronics decides depending on the operating range whether 80 V or 160 V is to be applied as measured voltage at the spark plugs. Via the signals S_IONS1 and S_IONS2, the DME sends the measurement voltage selection to each ionic current control unit.
Diagnosis instructions
If misfires are detected, faults are stored in the fault memory. The type of fault indicates whether ignition or combustion misfires were detected. 

Code: Select all


Ionic current measurement S65/S85
The following variables are measured for improved combustion monitoring:

    Spark duration
    Combustion quality

S65

The ignition coils incorporate an additional electronic module which can measure the spark duration and combustion quality.

The two measured values are measured via the conductivity of the mixture between the spark plug electrodes.
S85

The two ionic current control units measure spark duration and combustion quality.

The two measured values are measured via the conductivity of the mixture between the spark plug electrodes.
Spark duration

The spark duration is measured after the ignition spark is triggered. The conductivity is very high for the duration of the ignition spark; the ignition spark is identified by this. The aggregate is ms.

The spark duration varies within a value range of 0.1-1.5. The value drops to 0.1 when the ignition spark fails.
Combustion quality

The combustion quality is measured after the end of the ignition spark. The integral over the duration of combustion is created for this purpose. The aggregate is nSs (nano Siemens seconds, Siemens is the unit of conductivity).

The combustion quality varies within a value range of 0-5. The value drops to 0 when no combustion occurs.
Attachments
Ion_Module_V10_2.JPG
Ion_Module_V10_2.JPG (25.56 KiB) Viewed 3497 times
Ion_Module_V10.JPG
Ion_Module_V10.JPG (102.76 KiB) Viewed 3497 times
User avatar
AndreyB
Site Admin
Posts: 14292
Joined: Wed Aug 28, 2013 1:28 am
Location: Jersey City
Github Username: rusefillc
Slack: Andrey B

Re: Ion Sense

Post by AndreyB »

Niklas wrote:
Fri Jan 26, 2024 7:19 am
Hello Guys, why do we not use BMW-Ion-Sense Moddule from the V10?
Let's give it a try!

What's the part number of that BMW module - is it available on eBay for under $100? Next step would be mating plug part number or sourcing used. Glad to see lack of CANbus between module and ECU that makes integration really easy!
Very limited telepathic abilities - please post logs & tunes where appropriate - http://rusefi.com/s/questions

Always looking for C/C++/Java/PHP developers! Please help us see https://rusefi.com/s/howtocontribute
Niklas
Posts: 4
Joined: Fri Jan 26, 2024 6:47 am

Re: Ion Sense

Post by Niklas »

Hey,

Part Number is 13627834713

Unfortunately not under 100€ :-(

Another option is to use coils from M3 E9x with integrated electronic (0v is charging the coil, 5 v is ion current sensing)...


This post has some very usefull info:
https://rusefi.com/forum/viewtopic.php?f=4&t=2239

part number for the coil is 12137841754
Post Reply