inertia error

davehenrie · 3 June 10, 06:47

I'm getting the following error in the trace file.

Vehicle has zero or negative inertia in at least one direction

I have tried to track it down by cutting and pasting just about every part of the hdc or replacing engine files, suspension files, tire files etc. Where is the bad inertia usually hiding?

davehenrie · 3 June 10, 14:14

Well, as usual it was the obvious. The first section I replaced, or so I thought, was the main inertia line near the top of the hdc. I 'think' what I did was swap out a working inertia from another car, but I placed the new text in my recently created backup hdc instead of the hdc file I was trying to fix. So 'thinking' I had swapped out the inertia settings and still getting the problem, I moved on. and on...and on. Only when I went back to verify my previous fix did I find I still had the original values. Sorry for wasting your time...but I wasted an entire evening tracking that down...sheesh....
dh

bozont · 3 June 10, 14:19

na thats interesting.. how in the world could be inertia negative? its get always +

.. solved

davehenrie · 4 June 10, 02:10

I used Carfactory to come up with the numbers. Based upon an existing car and suspension file. But I see now, that the resultant numbers, are out of line with other cars in our field. I suspect this is due to an old F1c format. I'll have to do a little more research to come up with better numbers.
I think the 'negative' part was due to the numbers Carfactory came up with being outside a range allowed by the software. Since it doesn't understand those values, it assumes they must be negative.

dh

carham · 8 June 10, 23:31

dh...use the attached chart as a reference; it may help you get the inertia values in the ballpark:

davehenrie · 9 June 10, 01:30

Boy, that seems familiar. I'm sure I saw it somewhere. Looking at it, we can assume the two pink squares at 1100nm and 1200nm represent the Audi and Pugeot diesels. Therefore the engine inertia should be about 0.250. But the rest of the pink squares seem very low, 0.125 and lower. I'm assuming most of those would be very small F1 type screamer engines. I had taken the seat of the pants view that a P2 3.4L V8 would have an inertia about 0.165 and then I would increase that for larger engines.

But this chart would suggest a P2 V8 with just under 400nm of torque should have one of those ultra low values. Perhaps as low as 0.085. That just seems to be way to low a value.(an engine with that low of a value for rotational inertia, would probably hit redline before the throttle pedal reached the floorboard.) I would suggest a 4th curve, lets use bright Green, that starts at about 0.150 and travels between the pink race curve and the blue production blocks. But I have NOTHING to base that on, just feel.
dh

ps
I made a quick representation of where I think the bulk of our Le Mans Prototype engine inertia values should be. Hopefully I attached it properly. If you only knew how hard I had to push up against my graphic knowlege limits just to get this out there..... lol!

carham · 10 June 10, 17:43

Your assumption regarding the Audi/Pugeot diesels is correct.

The blue data largely represents derivatives of production engines. Since, the data scatter is rather large, because it covers a rather general range of engines, it can be assumed that P2 engines receiving some level of race modification, would preferentially be represented by the lower half of the blue data range as you have showed with the "green' line. For your project, the slope of the green line is the important consideration i.e., how is inertia expected to change as a function of increasing torque for the P2 engines.

Perhaps with more data representative of the "blue" definition, and a narrower filtering of the engines types/makes, the blue trend line could be replaced by other lines such as your green line.

The pink line represents the limited data that supposedly depicts the inertia/torque characteristics of ultra-high output, purpose designed and built race engines.

Anyway, the subject is interesting.....hopefully, we'll find addition data that can make the chart more useful.

Cheers.

Slicerer · 27 October 12, 22:51

I was getting the same error. Thought I don't know how the "intertia" function is at all connected to engine inertia. I honestly thought it had to do with the inertia of the entire car.

Could any of you please explain what some of this means?

And sorry for bumping an almighty ancient post.

Niels_at_home · 29 October 12, 23:15

Is this data from games / sims or real world?

3 June 10, 06:47	#1
davehenrie Join Date: Dec 2006 Location: Post Falls Idaho, in a house so new Google can't find it.	inertia error I'm getting the following error in the trace file. Vehicle has zero or negative inertia in at least one direction I have tried to track it down by cutting and pasting just about every part of the hdc or replacing engine files, suspension files, tire files etc. Where is the bad inertia usually hiding?

3 June 10, 14:19	#3
bozont Join Date: Jan 2008 Location: mokrance, slovakia Age: 33	na thats interesting.. how in the world could be inertia negative? its get always + .. solved Last edited by bozont; 3 June 10 at 14:28.

3 June 10, 14:14	#2
davehenrie Join Date: Dec 2006 Location: Post Falls Idaho, in a house so new Google can't find it.	Well, as usual it was the obvious. The first section I replaced, or so I thought, was the main inertia line near the top of the hdc. I 'think' what I did was swap out a working inertia from another car, but I placed the new text in my recently created backup hdc instead of the hdc file I was trying to fix. So 'thinking' I had swapped out the inertia settings and still getting the problem, I moved on. and on...and on. Only when I went back to verify my previous fix did I find I still had the original values. Sorry for wasting your time...but I wasted an entire evening tracking that down...sheesh.... dh

4 June 10, 02:10	#4
davehenrie Join Date: Dec 2006 Location: Post Falls Idaho, in a house so new Google can't find it.	I used Carfactory to come up with the numbers. Based upon an existing car and suspension file. But I see now, that the resultant numbers, are out of line with other cars in our field. I suspect this is due to an old F1c format. I'll have to do a little more research to come up with better numbers. I think the 'negative' part was due to the numbers Carfactory came up with being outside a range allowed by the software. Since it doesn't understand those values, it assumes they must be negative. dh

10 June 10, 17:43	#7
carham Donated Join Date: Nov 2007 Location: Michigan, USA	Your assumption regarding the Audi/Pugeot diesels is correct. The blue data largely represents derivatives of production engines. Since, the data scatter is rather large, because it covers a rather general range of engines, it can be assumed that P2 engines receiving some level of race modification, would preferentially be represented by the lower half of the blue data range as you have showed with the "green' line. For your project, the slope of the green line is the important consideration i.e., how is inertia expected to change as a function of increasing torque for the P2 engines. Perhaps with more data representative of the "blue" definition, and a narrower filtering of the engines types/makes, the blue trend line could be replaced by other lines such as your green line. The pink line represents the limited data that supposedly depicts the inertia/torque characteristics of ultra-high output, purpose designed and built race engines. Anyway, the subject is interesting.....hopefully, we'll find addition data that can make the chart more useful. Cheers.

27 October 12, 22:51	#8
Slicerer Join Date: Aug 2011	I was getting the same error. Thought I don't know how the "intertia" function is at all connected to engine inertia. I honestly thought it had to do with the inertia of the entire car. Could any of you please explain what some of this means? And sorry for bumping an almighty ancient post.

29 October 12, 23:15	#9
Niels_at_home Join Date: Aug 2005 Age: 33	Is this data from games / sims or real world?