LSPI Concern for GDI Non - Turbo Engine ?
- Thread starter ChrisD46
- Start date
No.
Yeah and ECU and TCU ofc can not talk to eachother. CAN-bus anyone ?
That's yet a new topic. Completely separate.
At this point I have no idea what you said was "complete and utter bs"
I see you have since edited your post though.
The edit notwithstanding you stated lspi can be mitigated with "boost control" and apparently the ECU "controlling the rpms"
I pointed out how IKC systems actually work. Did you disagree with that. Happy to post up the actual IKC maps and strategies.
I pointed out even if you could spark retard it wouldn't decrease lspi. It would actually increase it. Did you disagree with that?
Retarding timing is not lspi control.
Torque/boost and fuel is.
Seems like we need additional port injection like VAG did for some of the GTI/R engines.
Atleast with high sulphur fuel.
Torque/boost and fuel is.
Seems like we need additional port injection like VAG did for some of the GTI/R engines.
Atleast with high sulphur fuel.
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That's not how it does or would work.
First you have to be able to reliably detect lspi. The IKC systems cannot.
Then if using boost control you'd have to be able to pull boost fast enough to avoid the lspi once detected. You can't. You can pull timing in milliseconds for spark knock. Boost doesn't work like that. You'd literally have to just change the boost mapping and then you might as well change your entire engine output ratings and advertising.
We are talking about different things. No engine can do anything about the first PI. Thats were detection is important.
Im referring to the following occurrences of pi.
IE open wastegate, add more EGR, more fuel. ****ing about with spark will do nothing.
"Exhaust back pressure limits turbocharger efficiency and enhances conventional knock, as part of the hot exhaust gases remain in the cylinder [210]. Exhaust back pressure was also shown to enhance LSPI severely in [207]. The exhaust gas residuals increase the polytropic constant, causing higher End of Compression Pressure (�EOC) and End of Compression Temperature (�EOC) at stoichiometric operation [207]. The quantity of residual gases is dependent on the intake valve timing. At certain timings, the exhaust gas pressure wave from the previous cylinder will reduce the scavenging of residual gases."
Im referring to the following occurrences of pi.
IE open wastegate, add more EGR, more fuel. ****ing about with spark will do nothing.
"Exhaust back pressure limits turbocharger efficiency and enhances conventional knock, as part of the hot exhaust gases remain in the cylinder [210]. Exhaust back pressure was also shown to enhance LSPI severely in [207]. The exhaust gas residuals increase the polytropic constant, causing higher End of Compression Pressure (�EOC) and End of Compression Temperature (�EOC) at stoichiometric operation [207]. The quantity of residual gases is dependent on the intake valve timing. At certain timings, the exhaust gas pressure wave from the previous cylinder will reduce the scavenging of residual gases."
The ECU cant control the red boxes in fuel and oil.
So to be on the limit you need a strategy, and adaptation.
Latest most comprehensive study I found yet:
https://www.sciencedirect.com/science/article/pii/S0360128522000715
Remind me to not buy any DI turbo engine with less then 2.0L
So to be on the limit you need a strategy, and adaptation.
Latest most comprehensive study I found yet:
https://www.sciencedirect.com/science/article/pii/S0360128522000715
Remind me to not buy any DI turbo engine with less then 2.0L
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"An ion current sensor is employed in a 4 cylinder production SI engine for combustion diagnosis during combustion process, knock, and low speed pre-ignition (LSPI) detection.
The results show that the ion current peak value and ion current peak phase have strong correlation with the cylinder pressure and pressure peak phase respectively. The COV of ion current integral value is greater than the COV of IMEP at the same operating condition. Results show that the ion current signal is sensitive to different lambdas. Using ion current signal, the knock in any given cylinder can be detected. Importantly, the ion sensor successfully detected the low speed pre-ignition (LSPI) about more than 20 °CA before spark ignition."
https://digitalcommons.wayne.edu/oa_dissertations/1464/
The results show that the ion current peak value and ion current peak phase have strong correlation with the cylinder pressure and pressure peak phase respectively. The COV of ion current integral value is greater than the COV of IMEP at the same operating condition. Results show that the ion current signal is sensitive to different lambdas. Using ion current signal, the knock in any given cylinder can be detected. Importantly, the ion sensor successfully detected the low speed pre-ignition (LSPI) about more than 20 °CA before spark ignition."
https://digitalcommons.wayne.edu/oa_dissertations/1464/
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