I have a car with trionic 5.5 basically this system uses direct ignition cassette coupled with resistor spark plugs to ignite the fuel in the cylinders AND do some other pretty amazing stuff.
The spark plugs are resistor type I guess to reduce RF noise and electronics damage in the Direct ignition cassette (DIC) and they measure ion current in the cylinders to identify when combustion has occurred - this is especially useful for knock (detonation) detection - aka if the fuel ignites without a spark - (happens in forced induction engines...)
The interesting question which we have been discussing on my forum is - some people want to move the cassette off the engine, or use the cassette on OTHER engines (not me) by extending its reach with spark plug wires.
the discussion is surrounding the compromise of the ignition cassettes ability to receive the voltage signals from the spark plugs telling the ECU that knock has occurred. The problem with this is that without knock signals the engine would blow up... lol... so would the signals be compromised? well the understanding is that spark plug wires have resistance 4-8000ohms between each end... The funny thing is the spark plugs also have a 5k ohm resister in them... people are saying the spark plug wire resistance would block the signals!?
So our interesting debate (which no one seems to really know about cos we suck with electrics lol) is around, can you put spark plug wires on the cassette or would it compromise the ability of the cassette to receive accurate signals on knock (raw voltage signals).... The crux of the thing is - other people have done it and report that they still get knock signals - but the question is how sensitive!?! no one really knows
IF you were to imagine a raw ion knock signal (in volts) coming through the spark plugs (past the 5k ohm resistor) do you think a couple of thousand more ohms would really affect it? I don't understand electrics enough to really be able to fathom it...
I guess you can't really figure it out without knowing how much voltage the DIC feeds to the spark plugs (when not telling them to spark) to create the partial circuit (which the ions from knock/combustion then complete) right?
Or can the ions forming in the cylinder create an electrical charge (as opposed to creating a circuit) when I right that out it actually sounds like a dumb question because ions are charged particles right? - would they just create a favourable condition for the ion voltage to flow back up the plug into the DIC to be sent to the ECU? could ions in a cylinder create a sizeable voltage that wouldn't be affected by resistance.
I know spark plug leads need to have resistance because 40k volt or whatever burst conduction produces dynamic electricity where it doesn't just travel inside the core or something right? lol
It's a saab design and it's so smart, I just wish I understood it more, they really were brilliant. SOrry if I've spazzed anyone out with this long thread.
The spark plugs are resistor type I guess to reduce RF noise and electronics damage in the Direct ignition cassette (DIC) and they measure ion current in the cylinders to identify when combustion has occurred - this is especially useful for knock (detonation) detection - aka if the fuel ignites without a spark - (happens in forced induction engines...)
The interesting question which we have been discussing on my forum is - some people want to move the cassette off the engine, or use the cassette on OTHER engines (not me) by extending its reach with spark plug wires.
the discussion is surrounding the compromise of the ignition cassettes ability to receive the voltage signals from the spark plugs telling the ECU that knock has occurred. The problem with this is that without knock signals the engine would blow up... lol... so would the signals be compromised? well the understanding is that spark plug wires have resistance 4-8000ohms between each end... The funny thing is the spark plugs also have a 5k ohm resister in them... people are saying the spark plug wire resistance would block the signals!?
So our interesting debate (which no one seems to really know about cos we suck with electrics lol) is around, can you put spark plug wires on the cassette or would it compromise the ability of the cassette to receive accurate signals on knock (raw voltage signals).... The crux of the thing is - other people have done it and report that they still get knock signals - but the question is how sensitive!?! no one really knows
IF you were to imagine a raw ion knock signal (in volts) coming through the spark plugs (past the 5k ohm resistor) do you think a couple of thousand more ohms would really affect it? I don't understand electrics enough to really be able to fathom it...
I guess you can't really figure it out without knowing how much voltage the DIC feeds to the spark plugs (when not telling them to spark) to create the partial circuit (which the ions from knock/combustion then complete) right?
Or can the ions forming in the cylinder create an electrical charge (as opposed to creating a circuit) when I right that out it actually sounds like a dumb question because ions are charged particles right? - would they just create a favourable condition for the ion voltage to flow back up the plug into the DIC to be sent to the ECU? could ions in a cylinder create a sizeable voltage that wouldn't be affected by resistance.
I know spark plug leads need to have resistance because 40k volt or whatever burst conduction produces dynamic electricity where it doesn't just travel inside the core or something right? lol
It's a saab design and it's so smart, I just wish I understood it more, they really were brilliant. SOrry if I've spazzed anyone out with this long thread.