I didn’t get it if TJI require totally earlier spark advance ( in comparison with pure electric spark ignition) angle dew to some delay of building up a pressure in the pre chamber and forming the igniting jets or totally later spark advance angle , dew to the faster completion of the combustion process after the igniting jets has leaved the pre chamber ? Also wasn’t mentioned what’s the favourite type of materials for machining the pre chamber cap? I suppose lower thermal conductivity metals or even ceramics would be better but wanted to hear this by the lecturer . However , thanks for the info!
Pressure, temperature and time are factors in generating conditions for deflagration, detonation. It progresses faster than speed of sound. The combination of A/F and control of a rapid (but controlled) heat release are part of the benefits of TJI. Spark initiation of the chemical rate based flame front combustion will fail at high A/F ratios, lean. TJI will not only ignite at high A/F but, with multiple broad fronts of initiation with the hot jets that yield a rapid but controlled heat release. Rapid heat release allows initiation close to TDC. Compression side losses are reduced, in cylinder heat rejection is minimized, and full (better) expansion of the energy is closer to ideal. I have the same question on the pre chamber - but if it is ceramic and gets really hot there has to be a limit or self ignition will occur in the pre chamber. Ultimately simple injection into a hot chamber could control the process - re diesel pre chamber engines. Not stated here, but intake swirl, tumble etc that is good for rapid combustion of point ignition is adverse for in cylinder heat rejection and pumping losses. It would seem that a quiescent chamber would be better for ultimate thermal efficiency (short version)
@ I wonder if somebody tried active pre chamber with Hydrogen injected only in to pre chamber. Hydrogen burns extremely fast which usually is a problem for the pure hydrogen ICEs but if the H2 be injected only in the prechamber the rise of pressure in the main chamber couldn’t be so fast , my believe is that this could be beneficial for minimizing the TJI ignition lag and especially in applications with slow burning fuels as CH4 .
Great webinar, thank you for presentation Li Qiao 👏🏻
its great thanks for informations
I didn’t get it if TJI require totally earlier spark advance ( in comparison with pure electric spark ignition) angle dew to some delay of building up a pressure in the pre chamber and forming the igniting jets or totally later spark
advance angle , dew to the faster completion of the combustion process after the igniting jets has leaved the pre chamber ?
Also wasn’t mentioned what’s the favourite type of materials for machining the pre chamber cap? I suppose lower thermal conductivity metals or even ceramics would be better but wanted to hear this by the lecturer .
However , thanks for the info!
Pressure, temperature and time are factors in generating conditions for deflagration, detonation. It progresses faster than speed of sound. The combination of A/F and control of a rapid (but controlled) heat release are part of the benefits of TJI. Spark initiation of the chemical rate based flame front combustion will fail at high A/F ratios, lean. TJI will not only ignite at high A/F but, with multiple broad fronts of initiation with the hot jets that yield a rapid but controlled heat release. Rapid heat release allows initiation close to TDC. Compression side losses are reduced, in cylinder heat rejection is minimized, and full (better) expansion of the energy is closer to ideal.
I have the same question on the pre chamber - but if it is ceramic and gets really hot there has to be a limit or self ignition will occur in the pre chamber. Ultimately simple injection into a hot chamber could control the process - re diesel pre chamber engines.
Not stated here, but intake swirl, tumble etc that is good for rapid combustion of point ignition is adverse for in cylinder heat rejection and pumping losses. It would seem that a quiescent chamber would be better for ultimate thermal efficiency (short version)
@ I wonder if somebody tried active pre chamber with Hydrogen injected only in to pre chamber. Hydrogen burns extremely fast which usually is a problem for the pure hydrogen ICEs
but if the H2 be injected only in the prechamber the rise of pressure in the main chamber couldn’t be so fast , my believe is that this could be beneficial for minimizing the TJI ignition lag and especially in applications with slow burning fuels as CH4 .
@ as for the cap material, probably spark plugs insulator ceramics ( aluminum oxide)will be suitable and is proven durable .