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This is not correct. The BSG does absolutely apply up to 60nm of torque (see pg 30/84 here https://static.nhtsa.gov/odi/tsbs/20...49155-9999.pdf) - I believe up to a total of 5 seconds at a time but IIRC. I'm too lazy to find the actual SSP for the EA839, but it's the same engine. It's easily verifiable. The BSG does add quite a bit of torque when just driving around town or when flooring it.
In NA, it's used as a SS system, and to supplement torque from the ICE. None of the coasting functions that we see in EMEA are found in AMER.
I need to read this, and I will. Do you know if a similar document for the Q8 cars exists?
I need to read this, and I will. Do you know if a similar document for the Q8 cars exists?
If it's available it'll be on erwinusa.com. The D5 (A8) has a similar blurb on the EA839 engine. Same sort of deal, 60nm for up to 5 seconds from the BSG.
Angry, What do you mean by little legs, it’s obvious that the units are not lasting very long. A typical alternator lasts 80 to 150k miles and their only job is to charge a battery. Same device is now tasked to be a starter, dynamic breaking device, and maybe a power booster which it can do all four in a matter of seconds depending on the driver. I call what I observe, all the great info this group put up tells me it’s too small and over worked thus its service life is reduced. Maybe merc’s are not pushing theirs as hard, it’s probably a totally different design. If it’s not it than another device is killing it, battery??? I love my car and want to know what it is so I can disable it,
This is not correct. The BSG does absolutely apply up to 60nm of torque (see pg 30/84 here https://static.nhtsa.gov/odi/tsbs/20...49155-9999.pdf) - I believe up to a total of 5 seconds at a time but IIRC. I'm too lazy to find the actual SSP for the EA839, but it's the same engine. It's easily verifiable. The BSG does add quite a bit of torque when just driving around town or when flooring it.
In NA, it's used as a SS system, and to supplement torque from the ICE. None of the coasting functions that we see in EMEA are found in AMER.
To put some frame of reference around this, 60nm of torque is mediocre electric bike levels of torque, and for 5 seconds? without more of an understanding, my instinct is: big whoop. why are they even bothering with this?
I don't know if this is the correct document, of if there is another one that includes the RSQ8 and SQ8, or if we are supposed to just know that it includes the details for the "up-badged" cars in the Q8 line.
It says the installation locations of the batteries, the voltage converter, the 12 Volt pinion starter and the 48 Volt starter-alternator are, along with their functions and layout, identical to the components in the 2019 A8. But - we know not all Q8 cars have the 48 volt starter-alternator - I guess we assume they are referring to the cars that do - this is the only page they have in the Q8 document:
So I also downloaded 970293, The 2019 Audi A8 Electrics and Electronics - here are the applicable pages from it:
It says the mild hybrid functions are identical.
It lists combustion engine assistance by the bsg, but then it also says it's not designed to boost the torque and/or power output of the engine.
I take that to mean based on some of the other features they list that it basically is just being used to provide a more seamless comfortable S/S experience.
But still, what about in cars without a BSG at all? It doesn't seem like any of the BSG functions would be there. Too bad that they are not clear on this. It seems like there should be another document that clarifies this, and we just haven't located it yet.
Last edited by ThomasWShea; 03-31-2023 at 05:01 PM.
Angry, What do you mean by little legs, it’s obvious that the units are not lasting very long. A typical alternator lasts 80 to 150k miles and their only job is to charge a battery. Same device is now tasked to be a starter, dynamic breaking device, and maybe a power booster which it can do all four in a matter of seconds depending on the driver. I call what I observe, all the great info this group put up tells me it’s too small and over worked thus its service life is reduced. Maybe merc’s are not pushing theirs as hard, it’s probably a totally different design. If it’s not it than another device is killing it, battery??? I love my car and want to know what it is so I can disable it,
This is 1) Not a "typical alternator" and is a 2) relatively new piece of technology. Just because 1 vendor (Continental) is having issues with reliability doesn't mean that there is something inherently flawed with the HP output / size of device. We won't know root cause until we know but it's best not to make super general conclusions about this with little to no evidence.
P0 hybridization is quickly becoming an industry norm and it is *only* Audi thus far that has sucked at its implementation from a BSG perspective.
Originally Posted by ThomasWShea
To put some frame of reference around this, 60nm of torque is mediocre electric bike levels of torque, and for 5 seconds? without more of an understanding, my instinct is: big whoop. why are they even bothering with this?
CO2 emissions, specifically, and like Tesla, it's better to come up with 1 implementation (2019) that has regional specific functions than to come up with a bunch. Yes, they realized in 2023 that it's be better to ditch the lithium ion battery and the BSG altogether but I bet you it was never planned.
I don't know if this is the correct document, of if there is another one that includes the RSQ8 and SQ8, or if we are supposed to just know that it includes the details for the "up-badged" cars in the Q8 line.
It says the installation locations of the batteries, the voltage converter, the 12 Volt pinion starter and the 48 Volt starter-alternator are, along with their functions and layout, identical to the components in the 2019 A8. But - we know not all Q8 cars have the 48 volt starter-alternator - I guess we assume they are referring to the cars that do - this is the only page they have in the Q8 document:
It lists combustion engine assistance by the bsg, but then it also says it's not designed to boost the torque and/or power output of the engine.
I take that to mean based on some of the other features they list that it basically is just being used to provide a more seamless comfortable S/S experience.
But still, what about in cars without a BSG at all? It doesn't seem like any of the BSG functions would be there. Too bad that they are not clear on this. It seems like there should be another document that clarifies this, and we just haven't located it yet.
The SSP was from 2019. Things have clearly changed since then. And yes, the BSG supplements the ICE engine, and it says 60nm up to 5 seconds. Also, OBD11 will literally tell you what the torque applied by the BSG is at any given time. Check out the "live data" part of the belt starter generator. Also that last pic you have clearly says "internal combustion assistance by the starter generator". The 2nd pic also indicates rated output in motor mode (boost for the TFSI engine, for maximum 5 seconds) of approx 8hp.
Last edited by angrypengu; 04-01-2023 at 04:43 AM.
Note that Audi nowhere in their officially published marketing materials say that BSG supports ICE. Whereas BMW or Mercedes state that their cars have the power and torque of ICE xxxHP and xxxNm + electric motor xxxHP and xxxNm. But in these cars the electric motor is rigidly mounted between the engine and the transmission.
I am surprised that Audi decided on BSG which is more complicated, unproven technology. Probably it was cheaper to replace the 14V alternator with BSG than redesign the transmission and engine for internal electric motor.
Note that Audi nowhere in their officially published marketing materials say that BSG supports ICE. Whereas BMW or Mercedes state that their cars have the power and torque of ICE xxxHP and xxxNm + electric motor xxxHP and xxxNm. But in these cars the electric motor is rigidly mounted between the engine and the transmission.
I am surprised that Audi decided on BSG which is more complicated, unproven technology. Probably it was cheaper to replace the 14V alternator with BSG than redesign the transmission and engine for internal electric motor.
I would disagree that BSG is more complicated. If anything, ISG is more complicated, but then again, Mercedes failure points thus far have been on the 48V lithium ion battery, not the ISG. So in this case, Mercedes' more complicated implementation has turned out to be more reliable than Audi's. Good job VAG /s!
Folks should also keep in mind our cars do regen energy when braking/coasting. Audi added recovery regen braking to capture energy that way. I do not know if the P1 ISG implementation with MB has regen braking b/c it wouldn't be necessary due to the location of the ISG.
That said I cannot imagine the cost to replace the ISG. A BSG is easily replaceable and relatively cheap. An ISG failure would strike me as a $$ nightmare.
Last edited by angrypengu; 04-01-2023 at 06:10 AM.
This is 1) Not a "typical alternator" and is a 2) relatively new piece of technology. Just because 1 vendor (Continental) is having issues with reliability doesn't mean that there is something inherently flawed with the HP output / size of device. We won't know root cause until we know but it's best not to make super general conclusions about this with little to no evidence.
P0 hybridization is quickly becoming an industry norm and it is *only* Audi thus far that has sucked at its implementation from a BSG perspective.
CO2 emissions, specifically, and like Tesla, it's better to come up with 1 implementation (2019) that has regional specific functions than to come up with a bunch. Yes, they realized in 2023 that it's be better to ditch the lithium ion battery and the BSG altogether but I bet you it was never planned.
The SSP was from 2019. Things have clearly changed since then. And yes, the BSG supplements the ICE engine, and it says 60nm up to 5 seconds. Also, OBD11 will literally tell you what the torque applied by the BSG is at any given time. Check out the "live data" part of the belt starter generator. Also that last pic you have clearly says "internal combustion assistance by the starter generator". The 2nd pic also indicates rated output in motor mode (boost for the TFSI engine, for maximum 5 seconds) of approx 8hp.
@angrypengu On boost, page 27, second paragraph, last sentence: “The starter generator in the Audi A8 is not designed to boost the torque and/or power output of the TFSI engine.”
Stick with me I am just trying to talk this out to make it understandable for me 🙂
I have been confused but I think it is because of how I was defining of the word boost. I was (and i think most people) think boost means add more power, like a turbo. And I do believe that technically yes the motor mode is generating torque and the small amt. of 8 hp (or whatever), but it is not enough to change the engine’s performance or move the car. My understanding when I read the quoted sentence above changed. It made me think that though torque is applied it is basically just used to spin the engine up to the appropriate rpm so when the engine starts firing it feels totally seamless. The function bullets on page 26 do not use the word boost. I think when they use the word boost they mean: from zero rpm with no combustion, the motor spins (boosts) the engine up to the right rpm, at which point combustion begins etc. That is not what common man on the street will think if you say “the bsg boosts the engine”.
@angrypengu On boost, page 27, second paragraph, last sentence: “The starter generator in the Audi A8 is not designed to boost the torque and/or power output of the TFSI engine.”
Stick with me I am just trying to talk this out to make it understandable for me 🙂
I have been confused but I think it is because of how I was defining of the word boost. I was (and i think most people) think boost means add more power, like a turbo. And I do believe that technically yes the motor mode is generating torque and the small amt. of 8 hp (or whatever), but it is not enough to change the engine’s performance or move the car. My understanding when I read the quoted sentence above changed. It made me think that though torque is applied it is basically just used to spin the engine up to the appropriate rpm so when the engine starts firing it feels totally seamless. The function bullets on page 26 do not use the word boost. I think when they use the word boost they mean: from zero rpm with no combustion, the motor spins (boosts) the engine up to the right rpm, at which point combustion begins etc. That is not what common man on the street will think if you say “the bsg boosts the engine”.
It's an interesting quote that you surfaced. I agree with you that it's most likely not the definition that we think about which is why the EA839 torque and HP figures do not take into account the boost provided by the BSG. This is unlike ISG applications, specifically, IIRC. When I think about plug in hybrids as an example, it very clearly will indicate ICE and e"boost" figures. So basically the SSP isn't even entirely consistent throughout which is exactly like all of the other SSPs provided by Audi since the dawn of mankind
From what I see on OBD11, the boost is actually very very consistent, and generally speaking "max" boost occurs in between gear changes and specifically at low RPM. The other time I see it at max boost for reasons I cannot explain is on the highway at coast....(yeah, I don't get it.)
Situation #1 makes sense. Car needs to get going, BSG gives it a boost. Switch from Gear 1-> Gear 2, BSG gives it a boost, then the ICE engine takes over.
In any event, the BSG torque (duration and amount) is so miniscule that it's irrelevant. Don't get me wrong, I facking hate all of this 48V garbage. It's all just a waste of space, money, and time.
03-30-2023, 06:41 PM
