Sch.....rott Elektronik im Auto | Posts 32+

PrivatBereich wrote:

... As far as I can recall, the gyroscope doesn't measure lateral acceleration, but rather a rotational movement .

So, in the specifications for a gyroscope, like the ones used in the automotive industry, the rotational rate is usually specified in degrees per second. This makes the starting point time-dependent and captures the rate of change.

See also

"The rate gyroscope uses the Coriolis effect of the sensor element (vibrating resonator chip) to sense the speed of rotation (rate of turn)."

Since it captures the angular velocity, the position within the car is therefore irrelevant.
Let's remove my comment: "Definitely too far forward for detecting rearward movement." http://www.spp.co.jp/sssj/sirikon-e.html

PrivatBereich wrote:

Therefore, it shouldn't matter where someone is sitting in the car! Unless, of course, your car is so severely deformed that the rear actually turns more than the front . In that case, please send a photo of it .

Do you mean something like this?

Hi Julian,
Now, let's talk about the problem with current ESP systems:
If the ESP (Electronic Stability Program) control unit does not receive any steering input, then no control action will be taken.
So, if the rear end breaks loose due to a load shift reaction, and the driver doesn't steer to correct it, the ESP won't compensate either (this is where many serious accidents often occur). Counter-steering with ESP also needs to be done differently than without it. The ESP reacts to sudden steering movements and interprets them as a 'panic reaction,' intervening helpfully. Unfortunately, this intervention is often in the direction of the steering angle. However, this is undesirable when counter-steering, because it's not intended to indicate a desired direction (like when swerving) but rather to follow the steering in the direction of travel/slide. Therefore, you need to steer in the opposite direction much more gently/slowly so that the ESP doesn't intervene.
Right there, the instructor had to admit that ESP has significant limitations, likely because the system, for cost reasons, has to restrict its functionality to a smaller scope.

Hello Bertil!

The ESP system isn't quite that simple (assuming we're talking about Mercedes-Benz!). If a rotation around the vertical axis is detected that doesn't correspond to the steering angle, a correction is applied. If the rear of the car suddenly swerves to the right and you only steer slightly in the opposite direction (up to a certain point), the rear will continue to drift out, and the car will inevitably spin out of control.
Now, during this slipping process, the rotational speed of each individual wheel is measured and compared in order to detect any slippage.

If the rear of the vehicle continues to swing out, apply the brakes on the right side until the steering angle once again corresponds to the rotational speed around the vertical axis.
If you continue to steer further in that direction, the rotation around the vertical axis will simply follow the steering angle, and the ESP system will disengage.

And... since you mentioned the safety training. I'm sure you've often noticed with other participants that people do counter-steer (to compensate for the oversteer), but they only do it a little bit. Half a steering wheel rotation... then they remain fixed, even though the car could easily be steered into a full turn with a little more effort.
And that's precisely why ESP was developed, because most people steer far too little. If, according to your statement, the ESP were not to react to a lack of steering input, then the system would indeed be useless.

During the driving safety training, there's a test using this special plate. When the vehicle drives over it, the plate deflects to the right or left, perpendicular to the direction of travel, and gives the rear of the vehicle a nudge. We tested it, and even if you keep the steering wheel straight, the ESP (Electronic Stability Program) starts working immediately to counteract the unwanted rotation around the vertical axis until the rotation is eliminated. Of course, physics sets limits here, but depending on the speed, the vehicle quickly returns to following the steering angle. According to your thesis, nothing would happen, right?

@Gremlin:
Your way of expressing yourself continues to amaze me !

Hi!

That only makes me think of one thing: "Hollywood has stuntmen, Volkswagen drivers have ESP..."
Whatever it may mean...


Greetings: Marko

Hi Julian,

Julian wrote:

... If a rotation around the vertical axis is detected that does not correspond to the steering angle, a correction is performed.

That's exactly what I expect from the system... but it doesn't do it.

Quote:

If the rear of the car suddenly swerves to the right, and you only counter-steer slightly (up to a certain point), the rear will continue to swerve, and the car would inevitably spin out.

Exactly that is happening.

Quote:

Now, during this slipping process, the rotational speed of each individual wheel is measured and compared in order to detect any slipping. If the rear of the vehicle continues to swing out, apply the brakes on the right side until the steering angle once again corresponds to the rotational speed around the vertical axis. If you continue to steer further in that direction, the rotation around the vertical axis will simply follow the steering angle, and the ESP system will disengage.

That's how it's supposed to be. However, I was only able to reproduce this ideal process with the rear-wheel drive vehicles. Even the Peugeot (in my case, a 307) behaves in the same way as the Golf.

Quote:

And... since you mentioned the safety training. I'm sure you've often noticed with other participants that people do counter-steer (to compensate for the oversteer), but they only do it a little bit. Half a steering wheel rotation... then they remain fixed, even though the car could easily be steered into a full turn with a little more effort. And that's precisely why ESP was developed, because most people steer far too little. If, according to your statement, the ESP were not to react to a lack of steering input, then the system would indeed be useless.

"Teach a rally driver (like me) not to fully counter-steer as usual..." Have fun...

Quote:

During the driving safety training, there's a test using this special plate. When the vehicle drives over it, the plate deflects to the right or left, perpendicular to the direction of travel, and gives the rear of the vehicle a nudge. We tested it, and even if you keep the steering wheel straight, the ESP (Electronic Stability Program) starts working immediately to counteract the unwanted rotation around the vertical axis until the rotation is eliminated. Of course, physics sets limits here, but depending on the speed, the vehicle quickly returns to following the steering angle. According to your thesis, nothing would happen, right?

Unfortunately, this test involves extreme lateral acceleration, and the G4 ESP reacts normally (to a certain extent) as a result.
During a sudden load change, which happens more gradually, the system doesn't regulate because the angular velocity is too low, and that's the critical issue... the car starts to spin before the ESP even registers it.

Certainly, this is a borderline case and not something that happens every day (not even for me), but people should learn about the limitations of these systems in a security training and not blindly rely on them!

Hi Julian,
However, in a security training, one should learn about the limitations of these systems and not blindly rely on them!

That was exactly my concern!

joergs wrote:

is it now a PD or what?

Hi Jörg,

Yes, I'm going to embark on this PD adventure - hoping that it won't be too much of an adventure.

@everyone: Thank you for the congratulations.
I'll only accept it when I have the "little one" under my bottom.

P.S. And by the way, small? My Golf 3, minus 2 cm in length, minus 4 cm in width, plus 35 kg of weight, is equivalent to a Polo TDI with 96 kW.

@ulf

'And yet, it will definitely be a flying machine! In my opinion, it won't be an adventure. I've already put a lot of kilometers on my car and haven't had any problems! And it's the 96kW engine. You have significantly less weight in your Polo compared to my Passat!'

joergs wrote:

You definitely weigh less than I do in my Passat, considering you're driving a Polo!

Hi Jörg,

According to the catalog, the weight is 1155 kg without the driver (+ radio + full-size spare tire + 2 seat height adjustment mechanisms + speed limiter + multifunction steering wheel). So, I really went all out ).

In the Ibiza forum, the air-conditioned cars with 96 kW of power (averaging 140 horsepower according to DZR calculations) manage to do so in 3rd gear. Not quite the acceleration of my AFN tractor with 130 horsepower.

If the Polo also has the longer gearbox like the Ibiza, then the most striking effect will likely be the often-criticized, disharmonious power delivery (i.e., the sudden surge of power as the turbocharger spools up)... but we'll see.
Once I have the Polo, I'll write down some impressions about it.

joergs wrote:

... you're carrying quite a bit less weight in your Polo than I am in my Passat!

Okay, I'm ready. Please provide the German text you want me to translate. Yes, but quite a bit more than with his current tractor... the Ulf's feet would go numb with so little power and so much weight .....

During the driving safety training, there's a test using this special plate. When the vehicle drives over it, the plate deflects to the right or left, perpendicular to the direction of travel, and gives the rear of the vehicle a nudge. We tested it, and even if you keep the steering wheel straight, the ESP (Electronic Stability Program) starts working immediately to counteract the unwanted rotation around the vertical axis until the rotation is eliminated. Of course, physics sets limits here, but depending on the speed, the vehicle quickly returns to following the steering angle. According to your thesis, nothing would happen, right?


That's exactly what it does... nothing.

'The offset plate causes a significant jolt, which is even detected by the ESP system. However, in real life, I would never experience such a shock on the rear axle, especially if there's a front bumper installed.'
If you initiate a turn and then the rear end starts to slide out without any further steering input, then with a Passat and similar cars... NIX...
If the car starts to slide sideways, if you don't do anything, the ESP system will eventually detect that something is wrong. Then it will be too late, and you will end up stopping in the opposite direction of travel.
Or, you might make a steering correction because your 'butt meter' is telling you something is wrong. Then, the ESP (Electronic Stability Program) will recognize earlier that something isn't going as it should. The car will be caught, and it will turn in the opposite direction... again, the front of the car will be pointing in a different direction than where you intend to go.

@bertil
We were driving the rear-wheel drive cars through the curves at idle, just like the Passat.
'It probably wasn't that. I suspect that rear-wheel drive cars are more sensitive in this regard, as it's relatively easy for the rear wheels to lose traction and break away.'


'By the way, does anyone here own a Peugeot 106, maybe from around the 1996 model year?'
Okay, everyone, let's do a full emergency brake... but please, not in the curve... Wow... I swear to you on my honor, the rear wheels are completely off the ground (you can lift them up manually from the back! And I'm more of a skinny guy than a bodybuilder).

CU Gremlin.

@ulf


Wow, that's a real luxury car with all the fancy extras. Forget about those simple, basic trucks... it looks like you've really hit the jackpot!

Okay, but seriously: My Passat weighs 1580kg with me in it and a full tank. And in my opinion, it accelerates like a rocket! So, I think the Polo, including everything, probably weighs about 300kg less, which means it's a real speedster.
I agree with you on that point: the way the power is delivered is quite unusual. But once you get used to it, you might not want to miss it!


Regarding the ESP: you are certainly right. However, I wouldn't want to be without the ASR (traction control) with the 'wow' feature. Whether it's when starting off, accelerating out of corners, or... it works really well!

Gremlin wrote:

x world one wrote: The traction control system is a joke; it never seems to engage. At least, I haven't been able to make it work yet. In other vehicles, the ASR at least functions, see BMW . Okay, here's the translation: "So, without ASR, I can't get anywhere when it's wet. Even with a lot of throttle, it still slips too much on a dry track. Are you sure you have one? It happens to me even when I want to drive my test track in the wet. It has a really nice curve at the beginning that you need to take at 90 degrees for the measurement. When you apply the throttle there, the system starts flashing and cuts the throttle " "However, it does allow for a lot of wheelspin. It's not possible to start off with a lot of traction, and driving uphill in the snow is also a problem. The programmer used to be more capable in that regard..." CU Gremlin

I think that one has ASR, at least it also has ESP .
But an ASR (Anti-Slip Regulation) that only kicks in after the wheels have already made several rotations, and that requires you to see black marks on the asphalt – well, that's just not acceptable. This morning, I deliberately provoked it by driving with squealing tires. It wasn't a problem at all. It's possible that the ASR only becomes noticeable on very slippery roads, but for me, that's not the purpose of the system if it intervenes so late. I don't mind if the ESp (Electronic Stability Program) intervenes late, but the ASR? How does the ASR actually work in the Golf? Sure, here's the translation:

"Also, what about the possibility of the engine stalling?"

Hi,

@Ulf: You're probably going to lose those extra +35 kilograms through weight loss, right?

"Gremlin: You also notice the light rear end on the Ibiza. During sharper braking from higher speeds, you can also feel the rear 'wobbling,' and there's not much grip left on the rear wheels." While you can't lift it from the rear, the TDI engine is quite heavy at the front compared to the rest of the small (3.87 meters long) car.

Best regards,

Jan.

You also notice the light rear end on the Ibiza. During sharper braking from higher speeds, the rear 'wobbles' noticeably, and not much more pressure can be applied to the rear wheels. While you can't lift it from the rear, the TDI engine is quite heavy at the front compared to the rest of the small (3.87 meters long) car.


Unfortunately, the very soft suspension tuning of the VW Group vehicles also plays a significant role in this. The rear drum brakes, which are still partially used in some models, provide less braking force, requiring the front brakes to work harder.

While I'm not a proponent of stiffer or lower suspensions, as I believe those are only suitable for the racetrack and not practical for everyday use, I did achieve a noticeable improvement in steering stability with my Golf 4 TDI when I installed stiffer springs (Eibach ProKit). The driving behavior, especially when fully loaded, was significantly improved. Unfortunately, the vehicle was then 35mm lower, but it was still somewhat drivable.

Hi Julian,

twice no )

The Ibi has rear windows that provide good visibility, although their effectiveness is somewhat limited by the car's low weight.

Regarding the suspension, mine is the Signo version, which is supposedly "softer" than the Sport version, but I haven't noticed any difference. Compared to the Polo 6N I had before, the Ibi is noticeably stiffer, even though they share the same platform, which means something else must be different.

I suspect that the "sportiness" aspect, which is a key selling point for Seat, also plays a role here.

In the Ibi forum, there was once a discussion about weight distribution, with someone suggesting a ratio of roughly two-thirds front, one-third rear, which I immediately found believable.

Best regards,

Jan.