[disc]

Something bad happened with the latest update. A geared locomotive with automatic transmission, now can't reach more than 8 km/h, and the the RPM can go over 4000 while the max is 2100, and rapidly switching gears between 1st and 2nd back and forth.

[copperpen]

Matej Pacha, on 20 February 2014 - 06:28 AM, said:

Guys,

First of all, I'd like to stay calm now about new features like a new controller or including any kind of scripting into physics. We would be overstepping the ORTSv1.0 milestone.
So back to the original:


I need a bit more about this. What should happen if (please correct if something is wrong):

• I gear up one notch - nothing until...
  
• I pull up the throttle - the clutch is starting to transmitt some force to the wheels. The higher throttle setting, the higher force to transmitt.
  
• the clutch is about to close - the diesel RPM will match the train speed in proportion with the selected gear
  
• the clutch is on and I pull down the throttle (not to zero) - the clutch will remain closed and the diesel RPM will follow the train speed (with some braking force in proportion to the throttle setting - not implemented now)
  
• the clutch is on and I pull down the throttle to zero - the clutch will open and the diesel RPM will fall to idle. I can switch the gear and pull up the throttle again.
  
  
• the clutch is on, throttle is higher than zero and I gear up by a notch(es) - the clutch will open and the diesel RPM will fall/rise to the speed proportional to the new gear selection. Than the clutch will close again and the engine will follow the train speed.
  
• ... (please add some if you have some ideas)

Matej

That sequence of events will be correct for any unit that has a mechanical clutch. The units I am trying to get running correctly do not have a mechanical clutch. they have a fluid flywheel or torque converter, then the freewheel unit, then the mechanical gearbox.

1.Select first gear
2. Increase throttle and release brakes, higher throttle gives higher force to transmit to the gearbox.
3. At this point, increase the throttle will increase force, but decrease throttle will decrease force and reduce engine rpm because of the freewheel, thus engine rpm follows the throttle, not the train speed
4. engine rpm is never locked to train speed due to the freewheel between the torque converter ( clutch ) and gearbox. If train speed drives gear speed higher than throttle, the freewheel unlocks and engine rpm remains at throttle setting.
5. Gear change is locked unless engine rpm is at idle.


Far as the ORTS v1.0 milestone is concerned and adding new controllers, this has already been done in the new steam physics code and works very well without affecting the operation of MSTS. The resulting code can be carried over into ORTS vX with no difficulty.

[copperpen]

disc, on 20 February 2014 - 10:19 AM, said:

Something bad happened with the latest update. A geared locomotive with automatic transmission, now can't reach more than 8 km/h, and the the RPM can go over 4000 while the max is 2100, and rapidly switching gears between 1st and 2nd back and forth.

I have just tried a 4 car unit with automatic transmission and found no problems like you describe. Using X2046.

[Matej Pacha]

copperpen, on 20 February 2014 - 12:28 PM, said:

That sequence of events will be correct for any unit that has a mechanical clutch. The units I am trying to get running correctly do not have a mechanical clutch. they have a fluid flywheel or torque converter, then the freewheel unit, then the mechanical gearbox.

1.Select first gear
2. Increase throttle and release brakes, higher throttle gives higher force to transmit to the gearbox.
3. At this point, increase the throttle will increase force, but decrease throttle will decrease force and reduce engine rpm because of the freewheel, thus engine rpm follows the throttle, not the train speed
4. engine rpm is never locked to train speed due to the freewheel between the torque converter ( clutch ) and gearbox. If train speed drives gear speed higher than throttle, the freewheel unlocks and engine rpm remains at throttle setting.
5. Gear change is locked unless engine rpm is at idle.


Far as the ORTS v1.0 milestone is concerned and adding new controllers, this has already been done in the new steam physics code and works very well without affecting the operation of MSTS. The resulting code can be carried over into ORTS vX with no difficulty.

Hi,
so it's a feature request more than a bug report. I'll see what I can do, probably one additional parameter will be needed - something like ORTSGearBoxHasFreewheel ( 1 ).
BTW, the steam physics has been agreed to use additional parameters, because the steam model was very poor. There are some issues left with the gearbox, like the "hydraulic" vs. "mechanic" gearbox, DirectGears option, etc.

Cheers,

Matej

[disc]

copperpen, on 20 February 2014 - 12:32 PM, said:

I have just tried a 4 car unit with automatic transmission and found no problems like you describe. Using X2046.

See this video what happens:
Mvideo
First problem is the output power is much lower than the input power, while the game switching between gear 1 and 2. Then over 7 mph, the output power suddenly rises and the gear stabilised at 2nd.
Sometimes the train stops accelerating at 7 mph, and can't go over, while the RPM goes to infinite. For this train the max RPM would be 2100 but even on this video it goes over that.

[copperpen]

I cant view your video, it gives me an error 404 on that page.

[Fred]

copperpen, on 24 February 2014 - 03:19 AM, said:

I cant view your video, it gives me an error 404 on that page.

The video is there.

[copperpen]

Yes, it is there now, and I see the flick between gears, but speed is much more than 8kph. I don't get that gear behaviour, neither do I see any over rev of the engine. I do with the manual change because currently engine rpm is linked to gear and train speed same as MSTS. I wonder if the gear flick might be caused by having the values in GearBoxMaxTractiveForceForGears too close together.

[disc]

copperpen, on 24 February 2014 - 09:30 AM, said:

Yes, it is there now, and I see the flick between gears, but speed is much more than 8kph. I don't get that gear behaviour, neither do I see any over rev of the engine. I do with the manual change because currently engine rpm is linked to gear and train speed same as MSTS. I wonder if the gear flick might be caused by having the values in GearBoxMaxTractiveForceForGears too close together.

Not too close.

GearBoxNumberOfGears( 4 )
GearBoxDirectDriveGear( 4 )
GearBoxMaxSpeedForGears( 3 20 36 57 )
GearBoxMaxTractiveForceForGears( 52kN 40kN 27kN 14kN )
GearBoxOverspeedPercentageForFailure( 170 )
GearBoxBackLoadForce( 4500 )
GearBoxCoastingForce( 2000 )
GearBoxUpGearProportion( 0.85 )
GearBoxDownGearProportion( 0.35 )
GearBoxOperation( automatic )
GearBoxEngineBraking( direct_drive )

[copperpen]

Those look OK when comparing to other eng files. I guess at the moment it is the same as a single speed hydraulic unit that actually has a gear change happen in OR. Cause unknown.