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Insane overengineering of a car headlight
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tooki:

--- Quote from: Monkeh on April 03, 2022, 07:56:44 pm ---I was not suggesting they don't feel good - rather that they make inferior choices for fuel efficiency when confronted with real world hills, not idealised test tracks and driving around Heathrow airport. However, they're still far better than the average driver.

--- End quote ---
Sorry, can you clarify what you’re actually claiming? “Inferior choices” doesn’t tell me anything, since what’s “inferior” depends on what you’re optimizing for.

Just state in plain English what you think they’re doing wrong.
Monkeh:

--- Quote from: tooki on April 03, 2022, 09:03:54 pm ---
--- Quote from: Monkeh on April 03, 2022, 07:56:44 pm ---I was not suggesting they don't feel good - rather that they make inferior choices for fuel efficiency when confronted with real world hills, not idealised test tracks and driving around Heathrow airport. However, they're still far better than the average driver.

--- End quote ---
Sorry, can you clarify what you’re actually claiming? “Inferior choices” doesn’t tell me anything, since what’s “inferior” depends on what you’re optimizing for.

Just state in plain English what you think they’re doing wrong.

--- End quote ---

Was 'fuel efficiency' not clear? Behaviour I've encountered includes both unnecessary low gear usage and holding on to a high gear far too long, resulting in violent downshifts to maintain any sort of reasonable speed.

Anyway, it's my opinion that they're not as well optimized for terrain I have to deal with as some think. I do not have six pages of precise data to back it up, so sorry.
coppice:

--- Quote from: tom66 on April 03, 2022, 04:30:19 pm ---An automatic dual-clutch transmission is just as efficient as a manual transmission.  Arguably it is even more efficient because it can swap gears more quickly due to the built-in rev-matching, which leads to less time when the clutch is slipping or when no power is applied (fuel burn but with no output.)  That's especially important for city driving, but when on the highway roughly all automatic and manual transmissions behave similarly, due to most modern automatic transmissions having a lockout for the torque converter.

--- End quote ---
A modern torque converter transmission is just as efficient as a DCT at speed, because they lock up the transmission, bypassing the torque converter. Both tend to be more efficient than a manual at speed, because they have more gears to choose from. A manual with 8 or more gears would be pretty tedious to use, but its now normal for automatics.

Around town torque converter automatics have always performed well. The losses in the torque converter are offset by the narrow band CVT like nature of a torque converter automatic, filling in between actual gear ratios.
coppice:

--- Quote from: Monkeh on April 03, 2022, 09:05:34 pm ---
--- Quote from: tooki on April 03, 2022, 09:03:54 pm ---
--- Quote from: Monkeh on April 03, 2022, 07:56:44 pm ---I was not suggesting they don't feel good - rather that they make inferior choices for fuel efficiency when confronted with real world hills, not idealised test tracks and driving around Heathrow airport. However, they're still far better than the average driver.

--- End quote ---
Sorry, can you clarify what you’re actually claiming? “Inferior choices” doesn’t tell me anything, since what’s “inferior” depends on what you’re optimizing for.

Just state in plain English what you think they’re doing wrong.

--- End quote ---

Was 'fuel efficiency' not clear? Behaviour I've encountered includes both unnecessary low gear usage and holding on to a high gear far too long, resulting in violent downshifts to maintain any sort of reasonable speed.

Anyway, it's my opinion that they're not as well optimized for terrain I have to deal with as some think. I do not have six pages of precise data to back it up, so sorry.

--- End quote ---
Any issues with uphill driving respond well to kickdown. I find the main annoyance with modern automatics on hills, is when going down hill. The car detects its inclination, and often changes down to apply engine braking on a steep downward slope, but it can be rather quirky. I usually apply some manual nudging of the gearing in such conditions.
tom66:

--- Quote from: Monkeh on April 03, 2022, 09:05:34 pm ---Was 'fuel efficiency' not clear? Behaviour I've encountered includes both unnecessary low gear usage and holding on to a high gear far too long, resulting in violent downshifts to maintain any sort of reasonable speed.

Anyway, it's my opinion that they're not as well optimized for terrain I have to deal with as some think. I do not have six pages of precise data to back it up, so sorry.

--- End quote ---

I'd be curious what automatics you've been driving.

Certainly, my Golf's automatic really hates the low gears.  At 30 mph it's often in 4th or 5th, and above 40-50 mph it's pretty keen to get into 6th.   It often even starts off in 2nd if you're on a slight downhill slope (the gearbox has an angle sensor; it's reported in the diagnostics data.)  In some situations, it'll do that if the 1st gear clutch is getting too warm, for instance lots of city driving, with a corresponding boost to engine rpm to make the start in 2nd less aggressive.  I've never had it happen, but apparently if one of the clutches totally fails, then it'll just start using the alternate one in a limp-home mode fashion with limited power.

On a side note, it's quite interesting to see how the VW gearbox manages clutch slippage.  I have had a few instances where the car began to judder ever-so-slightly at low speeds, indicating it's slipping the clutch a bit too little, but after doing this for more than a few moments, it learns pretty quickly where the new bite point is.  Bite points are calculated with a kind of multi-point linear mapping, so it has a point for (e.g.) 10Nm, 20Nm and 50Nm as well as fully engaged.  During parking maneuvers, the engine acts as a constant torque source, with the clutch slipping as needed.  If you apply the brakes during operation, it seamlessly begins to withdraw the clutch to balance the brake, engine and clutch forces to reduce the output torque to the user's request. 

I know it's totally obsolete for electric vehicles (and indeed, when my car is in the fully-electric mode, any time the battery has more than the minimum-state-of-charge, it does not do any of this complex behaviour, instead, it uses only the electric motor with the clutches fully closed.)  But, you really do have to appreciate the engineering required to make an ICE-powertrain behave as smoothly as it does. 
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