Powertrain Feedback Collection

EV and their regenerative braking:

Electric vehicle dont properly use their regenerative braking system in a realistic way.


Happens always due to design/code implementation


Expected behavior:

Regenerative braking should take priority over using the friction brakes when not emergency braking/ESC active.

Hardware (probably irrelevant but here you go)

Intel(R) Core(TM) i7-8086K CPU @ 4.00GHz
RAM: 32 GB
GeForce GTX 1080 (8 GB)
WIN 10 20H2
It is a gaming laptop.


In depth explanation:

Unlike ICEs that at best can achieve zero fuel/energy consumption (by shutting down injection when coasting) electric motors can also operate as a generator, transforming the kinetic back into electrical energy for the battery again. The resulting braking force on the rotor of the electrical motor will transfer via the drivetrain to the wheels, slowing the vehicle down while recharging the battery.

This has several benefits:

• Reduced usage of the friction based normal braking system, resulting in less wear and less brake based air pollution.
  
• Range increase, especially in city driving conditions as a good percentage of the energy spent accelerating the car is recouped when coming to a stop
• Can allow for "one pedal driving". A sufficiently high level of regenerative braking may allow the driver to only use the accelerator pedal in average driving. All braking is done by releasing the accelerator pedal sufficiently and all acceleration is done by pressing it just enough.
  
• Depending on the - sometimes configurable - aggression level, regenerative braking can be heavy enough to warrant lightening up the brake lights depending on the vehicle

Regenerative braking is highly beneficial for both range and brake system wear and as such is usually the first braking system used in normal driving conditions.

BeamNG:

When coasting (fully releasing the throttle) EVs use regenerative brake to slow down faster than just coasting. This is fine, although one would wish for a bit more configuration options (more or less regenerative braking)

Braking:

Video 1: Emergency stop in an EV: (All videos have been recorded in safe mode)

• At the beginning of the brake sequence, regenerative (negative flywheel power) reaches arround -295 KW. This is like an 295 KW engine fighting with the car to stop it. The green charge area of the dashboard is fully lit.
  
• Detecting an emergency stop and with friction brakes having reached their full (ABS governed) potential, regenerative power and torque are greatly dialed back (from -224 KW to -112KW - basically halfed) which is arround the value you would get at this wheelspeed in pure coast mode.
  
• This is fine and realistic. An emergency brake, ABS action or ESC action means that regaining control of the vehicle takes priority over anything else, saving energy included. A high regenerative torque on the driven wheels could possible make an already unstable car loose it fully and as such it is only reasonable that ABS and ESC can do their job without having to worry to much about heavy motor braking.
  
• Driving with a keyboard of course has the tiny little disadvantages that any sustained braking is considered "emergency" as it only knows "pedal to the metal". The resulting lack of energy regeneration in addition to less efficient full throttle operation greatly reduces the range of keyboard driven EVs.
  
• There isnt much you can do... a keyboard is a keyboard and will never be good for any delicate throttle or brake response.
• It would however be quite helpful if you could increase the coasting torque in the tuning menu. (One pedal driving). In english... releasing the accelerator key should lead to much more significant motor braking than it does right now - if you desire so.
  - Keep coasting like it is now but give us access to the parameters inside the tuning menu. One example of such a system would be
  Updated Shiftlogic Automatic Transmissions by default0.0player
  
  that uses what I assume is some LUA magic to make it happen.
  
  
  

Video 2: Emergency stop in an EV with brakes removed (limiting to motor brake only)

• One would expect that with the friction brakes not delivering (being removed in this video) that there is no reason to cut motor brake. However as it turns out, the motor brake is dialed back the very moment brake pedal reaches 100 %, independent of how much actual brake work is done by the friction brakes. As a result, stuttering the brake in this case leads to a shorter stopping distance as the motor brake spents less time being cut in half as it happens @ 100 % brake pedal.
  
  100 % brake pedal = 50 % motor brake at most
  1 - 99 % brake pedal = 1 - 99 % motor brake at most = shorter distance to stop
  
  
  
  
• Of course this is a somewhat unrealistic scenario but it helps understand how the regenerative braking logic in BeamNG works.
  
• It would be interesting to see how real life EVs handle this. Maximum pedal pressure = emergency brake but lets say your brakes are overheated or dont work for any other reason.... one would wonder if you would also have a shorter braking distance in real life with 75 % brake pedal than 100 % brake pedal if the friction brakes are out of order.

Video 3: Unnecessary early use of friction brakes (The Issue)

• Switching the brake control to the mouse allows for precise braking control.
  
  
• Run 1: Trying to maximize regenerative braking shows promising brake power even though the pedal is only arround 50 % depressed. Friction brakes engage only to arround 50 %, too. Arround half of the braking power to stop the vehicle was done with motor brake. Engine load displays -100 % for a relative long time, indicating maximum regen brake usage.
  
  
• Run 2: (The Issue) Even very light use of the brake pedal immediately puts heat onto the friction brakes even though the requested brake power is
  
  1. well within the ability of the motor to regenerative brake alone without help of friction brakes
  2. very low so that no stability issues are to be expected
  
  This seems wasteful and while regenerative braking is still notable higher than in pure coasting mode, (shortly reaches -100 % engine load) one would expect that light to moderate braking (and no ESC/ABS activity) would be done by motor brake only.
  
  The almost nonexistent use of the friction brakes in a calmly driven EV is the reason for the very high energy efficiency in city conditions and also explains why VW uses rear drum brakes in the rear wheel drive ID3. You could use disks of course but what for? They will rust away due to lack of use as most regular braking is done by the motorgenerator. Particulary on an RWD motor one, as the aft brakes are used far less in the first place. The Vivace E is FWD so it is a somewhat different story but it is still debatable if it really needs to use the friction brakes all the times.
  
  
• Run 3: Quick hard braking but still more soft than a keyboard shows increased regen (up to -80 % motor load)
  
  
• Run 4: More softer starting of the hard braking shows high regen values

Video 4 - Just for comparsion, this is the coasting spin down (just releasing the throttle and not doing anything until the vehicle is stationary again)





Other EV related thoughts:

• You cannot shut down an EV due to the engine being always on. Maybe daylight lights and dashboard screen could be turned off when in P.
  
  
• EV in both real life and in BeamNG have no use for a cardan/driveshaft. This means one animated object less than a combustion engine car. Maybe those saved computer ressources could be spent in animating the halfshafts? I dont know anything about coding but seing that we have cardan shafts spinning at 9000 RPM one wonders if we could get a bit more animation on a vehicle that otherwise will never have anything - visible - spinning beyond the wheels.

Thank you for consideration.

 

k I'm just here if this is wrong or not and if it is that's fine so can we end the conversation here?

 

when using clutch assist and throttle assist if you brake a bit and downshift with no throttle, throttle assist will not revmatch up and the wheels will spin

 

The topic/issue to bring up is...
the transmission not throwing you out of gear in a misshift in a manual transmission car

This happens when...
you change from one gear to another by not using the clutch at all or not using the clutch properly

Instead it should...
not allow you to go into a higher or lower gear when the clutch is not used properly. Even sim-cade games like Forza or Euro/American Truck Sim do this, so I don't see a reason why BeamNG can't

My specs are...
GTX 1060 6GB, Ryzen 5 2600, 16GB RAM, Dualshock 4, Logitech G29, Thrustmaster T300RS, keyboard

 

I was talking about engine braking
--- Post updated ---

Are you just saying something or replying to my comment

 

it would be good if arcade automatic could skip gears on the t-series 12 speed manual for faster acceleration

 

The topic/issue to bring up is...
T-Series and other heavy trucks in BeamNG do not support range/splitter preselector gearboxes. Users that have H-pattern shifters would benefit from a toggle switch for high and low range just like an Eaton-Fuller transmission. The current rangebox selector changes immediately and is only enabled for heavy trucks with mods. Splitter would be another nice addition for 13-18 speed boxes.

This happens when...
Using any H-pattern manual transmission with greater than 6 speeds.

Instead it should...
Shift 1-6, toggle the range selector, shift 7-12. Ability to split gears would add immersion as well.

My specs are...
N/A

In Addition...
As many other users have reported, the transmissions could use some further development. I strongly recommend reviewing the "Updated Shiftlogic Automatic Transmissions" mod by @default0.0player. The changes they've made to torque converter performance and electric motor regen are truly wonderful and accurate.

(https://www.beamng.com/resources/updated-shiftlogic-automatic-transmissions.16947/)

 

deforming cars in a certain way can cause oil starvation when the engine is upright, idk why

 

Breaking the oil lines

 

ah right

 

thats a thing?

 

probably not but let’s pretend it is

 

I think I read somewhere that the devs are planning to simulate oil pan damage in the future.


On the topic of powertrain:

https://www.beamng.com/threads/0-21...e-before-reporting.75298/page-37#post-1270488

Text copied below:

It would be most interesting if you or another dev would make a dev blog about the inner workings of

• ABS
• TCS
• ESC
• E-Diff
• ActiveLocking differential
• Adaptive dampers
• Torque vectoring differential

Honestly, I find it quite sad that you spent a lot of research and codework on this stuff and then all we ever get as information is

"we added it".

And while a people might have a general idea of what it does precisly, having an in depth explanation about it and its effect on the game would be highly appreciated.

 

Maybe oil level underneath the pickup for the oil pump, likely the same behaviour if the engine is upside down. Could be a define engine angle to the ground plane when oil starvation starts.

 

This so much, I would love a writeup how 0.20's new powertrain additions (such as eDiffs) work.

@topic: The Covet's fourth gear of it's automatic transmission could be far shorter IMHO, even though it's supposed to be a overdrive it bogs down the car considerably, even with a turbo.

Covet GTz 4WD when :^)

Or what about a 4Matic-like powertrain for the ETKi with drive modes?

 

https://wiki.beamng.com/FrictionClutch
This is intentional, otherwise you have to tune the clutch torque EACH TIME you tune or modify the engine.

 

So there's no "oh yeah we will implement that asap"?

 

most likely the next update

 

on my 96 ford thunderbird with a 4 speed auto you can lock out overdrive. this should be an option in beam so auto 4s dont keep shifting into over drive as soon as you let go of the throttle