Apocolipse

Gotta turn on airplane mode

jefnvk

The manufacturers do not drive around public roads to get fuel mileage data, period, end of story. Had you bothered to read the link I provided, you would know that those numbers come from strapping the car to a roller bench and driving a simulated program. Those programs give you the numbers that the EPA says you can put on your sticker. Yes, there is a reward for start/stop technology, no, it is not tested on the public roads. Yes, the company has to test the car first, again not on public roads. They strap it to the rollers and run the program it is going to be run on, and optimize largely to that. It is how VW got away with cheating on their emissions, they programmed the ECU to recognize when it was in this test and to change engine mappings. Lastly, even if the company were testing fuel mileage on public roads, which they aren't, they wouldn't do it in a camo'd car with fake body panels and wrappings that catch air which reduce economy.

Mikec7z

i did read the link, and i was familiar with the process before you posted it.

My point is... does the manufacturer do this in real life, to try to get the car to fail in real life, so that IF the car cant go from EV mode back to gasoline mode without some odd glitches occurring, then the manufacturer does not suggest to the testing facility with the rollers to run the tests in this fashion?

In simple terms... if im GM, and im at a testing facility with my car, is it possible that i say to the testers "hey, this car has something pretty cool, it can go into EV mode when you are below 30mph, and on top of that, it can still run in EV mode even after the car has ran out of gasoline, we allowed it to do that in our programming, it was a CHOICE we had to decide whether or not to do, and after we TESTED it, we decided it works just fine in the real world, so its gas mileage per tank is a more complex number to calculate, pretty cool huh?... here are the buttons you press to make this strategy occur..."

and do you think GM is going to suggest they do this at the testing facility IF THE CAR SHUTS OFF AND FAILS WHILE TRYING THIS? of course they wont.

Thus, is it not possible that GM would run this test, in real life, to make sure the car does not fail... PRIOR to turning over the car to the testing facility?

What is so hard to understand?

Is your argument genuinely with me... that GM would never test to see if this works if it was a plausible strategy, they would instead let the EPA guys with rollers be the first to try it?

Are you out of you mind?

Red67John

You do know don’t you that the manufacturers conduct their own mileage tests in on four wheel dynos according to strict RPA protocols and report the results to the EPA? The tests do not really allow for experimenting or varying from the specific protocols.

The EPA has only one test facility, in Ann Arbor, where six drivers randomly test only 15% of new models, or cars that they suspected the manufacturers may have fudged numbers on.

Mikec7z

unless you guys are trying to tell me, that GM does NOT have their testers of the vehicles (nothing to do with EPA NUMBERS RIGHT NOW)

unless you guys are trying to tell me, that GM does NOT have their testers of the vehicles see how far a car can go on a tank of fuel while they are out cruising in the real world... then what is your point?

Do you honestly think that GM is not interested how far their car can go on a single tank of gasoline and might tell their testers to check it out and see who can go the farthest? Is that so unbelievable to you as a human being, that you are going to argue and insist im wrong, over and over?

Its a statistic every model of every car made has up for viewing.

EPA or not, GM tests this stuff, and not just on rollers.

Good lord guys.

Mikec7z

2 more people added to the ignore list. Not worth it

mschuyler

All this angst on a THEORETICAL argument about an "EV Mode" that no one knows even exists? Your arguing about angels on the head of a pin and, I think, vying to have a bigger ignore list than defaria. C'mon, lighten up, guys.

Boiler_81

jefnvk does testing on preproduction vehicles every day. Until last year I was working for a tier one and had worked on many new vehicle launches. As you were told, there is no OEM running tests to see how far they can go on a tank of gas. There is absolutely no reason to.

Mikec7z

EV mode or not... there is something that occurs as the car is becoming low on fuel.

So you guys want me to believe... theres no reason to test and make sure a car does not die, if has shown signs or failed in the past, which it did in a similar situation prior, when the drivers ran it low, or completely out of, fuel?

no need to test and see if it is fixed or not... just call it a day, and pretend that its solved because engineers in a lab gave us the thumbs up. They have rollers.

I see now.

And if the car did have an EV mode, they would not want to test in the real world to be able to accuratly brag how far it can go in EV mode.

And the people who test them, may or may not be survey oriented people, whos jobs are to drive the car and see what they think of the car, and are not told about the EV mode should it have one, so they are not allowed to play around and test it when the car runs low on gasoline.

None of that is possible that the testers would check it out for themselves.

GOT IT!

Long resume's convinced me you guys are correct. Ill be quiet now. I lose you all win. Next topic apparently.

Good work, thank you for all helping solve whats going on.

The cars aren't dying in the real world, and people in the real world are not testing them. Testing only takes place on rollers.

Got it.

And GM has the same failures happen on rollers as they do in the real world since the rollers reveal all the same failures that occur in the real world, and they were 100% fine with sending the cars out that way with a likelihood of failure which they found while on the rollers, and told the drivers to use jumper cables to fix the car if it happens, even though they already know the jumper cables won't solve it, since they tested those in the lab, when it was on rollers. And they did not tell the drivers how to solve it the real way, they thought it was more fun to throw them to the wolves with bystanders and camera phones.

Got it.

(we are going to see how many minutes and hours and days it takes for you guys to realize how intelligent I think you are right now, and I am done talking. its your thread now. Goodluck)

jefnvk

Im not privy to every last GM test procedure, so no I can't definitely say they don't, or that side bets aren't possibly wagered on such things. What I can say is if you want to brag about numbers, A) human drivers are bad at beeing smooth with input required to get optimal numbers hurting mileage, B) humans are wildly variable and two different drivers can give you significantly different numbers, C) mules are covered in all sorts of surfaces that create drag and reduce aerodynamics harming mileage, and D) even if they did manage to better EPA numbers, the EPA numbers are what has to be advertised anyhow.

Not to mention, as much care is taken to keep these cars as secret as possible, a program in which you're running them out of fuel on purpose seems a bit silly.

Red67John

Well when you pontificate, which you do as much or more than most anyone on this forum, and you drone on about Chevrolet turning the car over to EPA testers... I was simply pointing out that contrary to what you arrogantly claimed to know about the EPA mileage testing process... oh well. Feel free to to ignore me.

Apocolipse

Welcome to the C8 forum hahahahaha

mammoth713

unlikely

(I am an EE)

I would place $$ on something more like wire harness design issues, DC/DC power converters failing, CAN bus integration issues w/ all the different body modules, etc..... those are much more realistic issues they will run into

I'm sure they have smart enough engineers to figure it out

Bill Dearborn

A lot more difficult than that. Every discussion of the 737 problem usually gets around to discussing the angle of attack sensors and that they were having issues with them. The Indonesia crash may well have been due to a faulty sensor. However, the automatic system that uses an angle of attack sensor should probably have some way of determining if the sensor is giving it true data. Hard failures are easy to detect, the ones that are not so easy are where the sensor is producing data well within it is design parameters but just totally wrong. Maybe applying a plus sign when a minus sign should have been assigned. Usually this kind of stuff is found when a full FMECA is performed on the subsystem to determine what the failure modes are, the effect of those failure modes and how critical they are. Basically, sit down and analyze how the system behaves when tens, hundreds or thousands of different types of failures occur.

Automotive systems have been very similar to aircraft systems for at least 25 years. They are a system of systems and all of those systems interact with each other and send data back and forth between each other. Throw some incorrect data into the mix and things go haywire very quickly. All it takes is one module that is in the process of failing that produces incorrect but within expected range data. A high resistance on one line inside a solid state component slows it down after being triggered with two write sequences in a row but works fine with just one write sequence followed by a read sequence and then a second write sequence. Inside a system that is processing hundreds of write and read instructions it shows up as a GOTCHA about every 10 hours of operating time.

Bill

mammoth713

I have worked on plane control boxes and I would be thoroughly surprised if boeing didn't have more redundancy with the whole AOA sensors and supporting software or whatever...

I think there's more to the story than the public knows; I'm waiting for more facts to come out.

vndkshn

For
Real

There are hundreds of possible reasons that car needed the tow, sitting here bickering over "reports" of "electrical issues" without a solid SOURCE (example, someone from GM going on record) is ridiculous.

Mikec7z

so its not ridiculous for the engineer to believe jumper cables are the solution...

but it IS ridiculous to observe on 2 occasions that the jumper cables, while the engineer believed they were the solution, turned out to NOT be the solution?

And its ridiculous to point out that the 48 V system would not be boosted by such jumper cables?

And its ridiculous to observe that the 2 times this has occurred, were both at gas pumps...

and thus its ridiculous to realize that being low on fuel prior to stopping the car at the gas pump, is part of the equation to causing the car to then have a shortage in the 48V system...

And its not ridiculous to point out that a c6 or c7 won't start when its ignition computer theft deterrent systems are malfunctioning from low voltage...

But it is ridiculous to point out that these same theft deterrent ignition systems would be 48V on the c8, as vehicle ignition is something GM would not want to be able to be "hacked" into, considering this global b/can/bus system is the hoped future on all GM vehicles, including self driving electric cars...

and thus it is also ridiculous to determine that the 48V system, which the jumper cables don't assist, being low, is why these 2 cars were thus towed...

and its ridiculous to determine it has to be something to do with low fuel, that causes this 48V system to be ran down...

and its ridiculous to realize an alternator SHOULD keep the 48v system charged no problem, unless of course the vehicle was running in EV mode prior to the gasoline fill-up, which would make logical sense if that were the case.... because when else are you going to run in full EV mode unless you ran out of gas?

but as i said above, my theory does not crux on only EV mode, my theory is simply pointing out that SOMETHING drains the 48V system, more than expected, just prior to gasoline fill ups, since we are 2 for 2 empty vettes needing more 48V power.

.... or else you guys are saying that GM engineers are just taking shots in the dark, and they had no indication of a low battery, they just found it wise to hook jumper cables up for the heck of it, and it coincidentally happened only at gas stations, none of their other pit stops they take. No pattern at all.

Got it

I'll stop back in another few days and see if you guys make anymore progress while im gone

JoesC5

The 2019 Audi A7 4 door sedan with a turbo V6 and a 7 speed DCT has the mild hybrid setup with 48 Volts. I have not seen any photos of them being hauled off from a gas station. Maybe the Germans have it figured out.

Mikec7z

while im gone, it would be productive if the audience attempts to wrap their minds around the problems GM is going to face, with free road side assistance bills, if and WHEN the 48 V system does need a new battery or need a jump. (after all, 48v jump boxes arent for sale at autozone or walmart last time I checked)

and please, don't assume the cars at the gas station needed their 48V systems jumped... i totally agree, those have a super complex global b can/bus problem that we cant begin to speak about...

so since the conversation is obviously dead in that area until GM gives us an official statement as thread participants above require before they can converse...

lets just focus for a bit on this 48v system battery... WHEN it does go dead... how is GM going to stay afloat as a company when cars are going to have to be towed for low batteries... notice i didnt say dead... i said low.. anytime a 48v battery is low... cars need towed.

Lets take the convo there... and get completely away from the mysterious complex issue that plagued these 2 c8's



And if you guys really want to be adventurous, lets examine what would happen on the GM flagship vette (which has EV motors in the front of the car)... lets talk about hypothetically what would happen if THAT car (not the 2 at the gas station of course)... THAT car had the ability to run on EV only and put the rear in neutral, and GM used the electric engines to boost the gas mileage per gasoline fill up to get that car into a whole new realm of range on a tank of fuel, relative to the competition...

and then lets look ahead to what the EPA and also the NHSTA might reward vs punish in cars that have this longer range than other non EV assisted cars...

and then lets think for a bit if this would be a figure GM would be proud of and brag about to the public... its gas tank fill up vehicle range...

And then lets think for a bit... if this might cause the batteries to run dead on the 48v system, since the ICE is not spinning the alternator.

A lot to think about for many people here, im sure. The future is so foggy and mysterious!

We should just wait for the GM official announcement to consider any of this relevant discussion. Im not sure GM even has an EV front wheel drive powertrain on the vette... all the sources that say it is coming, they could have just been lying or have no idea what they are talking about.

And i dont happen to know a few of them personally, who can attest that the front wheels will be powered by electric motors.... nah, thats all a lie and speculation too at this point

NY09C6

I skipped most of this thread but all manufactures will be implementing 48v mild hybrid systems around 2025 unless regulations change or they go straight to full EV. They cannot meet CAFE without it. Their suppliers already have the tech ready to go. This will not be a GM issue.