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Title: Engine stall after deceleration MED9.1 (Atmo to big Turbo project) Post by: 5rki on January 12, 2019, 07:11:14 AM Engine stall after deceleration MED9.1 (Atmo to Turbo project)
Hello guys, maybe anyone experienced a problem with VERY huge ball bearing turbochargers when engine is hot and release the throttle so engne decelerates and it simply dies. That is only condition that we face any problems all other works perfectly. The condition happens in OVERRUN phase when RPM are dropping down (deceleration) and in one moment aiflow gets up instead of down, injectors close down (cut-off) and again turn of when IDLE function kicks in but too late and engine turns off. Haven't tested hacking cut-off input parameters yet. When for test MAF disconnecded or engine temperature cold -> engine does not stall in any case. Attached log when engine stalls also rich in deceleration... It is clear maf rise while deceleration problem and would like to ignore it or to hack coolant temperature dependant maps. Hacking idle speed function, timers, codewords and other things is not proper approach and does not make any results. It is clear torque intervention on deceleration with fuel cut off command due to DK/AIRFLOW/FILLING/LOAD not in the alawable deviation. When engine is cold does not stall. So question is if deceleration fuel cut off temperature and gear dependent maps will do the trick :) or there could be some interesting different aproach. Maybe someone has some experiance or can hit a bit. Thanks for any kind of hints in advance. Title: Re: Engine stall after deceleration MED9.1 (Atmo to big Turbo project) Post by: littco on January 12, 2019, 03:14:49 PM Engine stall after deceleration MED9.1 (Atmo to Turbo project) Hello guys, maybe anyone experienced a problem with VERY huge ball bearing turbochargers when engine is hot and release the throttle so engne decelerates and it simply dies. That is only condition that we face any problems all other works perfectly. The condition happens in OVERRUN phase when RPM are dropping down (deceleration) and in one moment aiflow gets up instead of down, injectors close down (cut-off) and again turn of when IDLE function kicks in but too late and engine turns off. Haven't tested hacking cut-off input parameters yet. When for test MAF disconnecded or engine temperature cold -> engine does not stall in any case. Attached log when engine stalls also rich in deceleration... It is clear maf rise while deceleration problem and would like to ignore it or to hack coolant temperature dependant maps. Hacking idle speed function, timers, codewords and other things is not proper approach and does not make any results. It is clear torque intervention on deceleration with fuel cut off command due to DK/AIRFLOW/FILLING/LOAD not in the alawable deviation. When engine is cold does not stall. So question is if deceleration fuel cut off temperature and gear dependent maps will do the trick :) or there could be some interesting different aproach. Maybe someone has some experiance or can hit a bit. Thanks for any kind of hints in advance. The mk7 Simos18 does exactly this as well on large hybrids . It’s a simple case of adjusting the mass air flow maps to compensate and not trigger the torque intervention fuel cut off. Try adjusting the load maps in the low rpm range to stop the TM level 1from occuring. |