Blade Runner Redux - Tesla Cybertruck!

[redpoint5]

The newer laws don't make sense. In Oregon, you've got to change lanes if you can, which I do anyhow, but that won't help anyone not get hit. If people saw the cop, they wouldn't hit them. Not seeing them is the problem, and having a law requiring to move lanes isn't going to help that.

[aerohead]

Originally Posted by redpoint5

If we disagree, it's probably about the definition of "significant".

I'll arbitrarily pick 3% as my threshold for what constitutes a significant difference with driving technique alone, and confine the dataset to the middle 80% of the normal bell-curve distribution, tossing out those who drive like the gas and brake are on/off switches, and likewise those who only drive steady speed on the freeway, and therefore technique doesn't play a factor.



If you're thinking about it, might as well speculate.



Even full self-driving fails to do this, ignoring the red light ahead and accelerating towards it despite sensing the red light.

It matters much less when you can get 80% of that back, though.



What percent difference do you speculate driving habits (same cruising speed and HVAC use) alone account for?




I have not, which is why I suggest the test, especially with a forum member so relatively nearby (I'll say hi to freebeard while I'm there).

Having difficulty measuring to 1% would only matter if that's how insignificant the difference is, which would reinforce my point.



I've only twice brought the Prius plug-in from zero EV range, back to full using regen (only ~3 kWh), and that was one of the instances. Ended up wasting a good deal of energy downshifting since once the battery was full, it was no longer slowing the vehicle.



My spidey senses tell me it would be a very extreme scenario where 40 of the 250 mile range is provided by regen. Now that I've made that assertion, I'll see if math tends to support it...

According to Fueleconomy.gov, the Bolt uses 28 kWh per 100 miles.

40 regen miles / 100 miles = 0.4
0.4 * 28 kWh = 11.2 kWh gained from regen

The way to think about that is to imagine 11.2 kW (15 horsepower) being regenerated for 1 full hour. Of course, slowing isn't just a one time event, but spread out over the full trip length, and capable of up to 70 kW (94 horsepower).

In a hypothetical scenario where one could achieve full regen for 1 continuous regen event that supplied the full 11.2 kWh of charge back to the battery, it would take nearly 10 minutes.

It seems unreasonable to me that the Bolt could, on average, gain 40 miles of range by regen. My guess would be closer to 4 miles of range, on average. Some trips would be zero, like steady freeway cruising, and others would be more than 4, like stop and go traffic.

The quanta he reported was constrained by five EPA test protocols legally mandated to be used for new car certification in the USA.
He wasn't given any special latitude.
And the premise of EPA testing is that, anyone 'driving' a BOLT on the same dyno maps 'WILL' come up with the identical 40-miles that GM experienced.
The penalties for misrepresenting car performance are typically too great for an automaker to risk it.

[redpoint5]

Originally Posted by aerohead

The quanta he reported was constrained by five EPA test protocols legally mandated to be used for new car certification in the USA.
He wasn't given any special latitude.
And the premise of EPA testing is that, anyone 'driving' a BOLT on the same dyno maps 'WILL' come up with the identical 40-miles that GM experienced.
The penalties for misrepresenting car performance are typically too great for an automaker to risk it.

I'm saying you either misheard, misunderstood, or the engineer was mistaken about regen adding 40 miles of range to a car that would otherwise have 210 miles of total range.

In whatever the EPA test circuit is, I guarantee ~20% of the energy isn't just being wasted by the brakes.

At any rate, the ability to return 80% of braking energy back into useful work makes "technique" relatively unimportant for EV drivers.

In a study on the energy lost in brakes, it was estimated that when a car is brought to a complete halt from 70 mph, approximately 587.43 KJ of energy is wasted. This is equivalent to 0.16 kWh or the energy required to power a 160 W TV for an hour.

11.2 kWh from all regen / 0.16 kWh from 1 regen braking event from 70 MPH to 0 = 70 braking events.

In other words, during the 250 mile trip in a Bolt, on average, a person would have used regen equivalent to braking from 70 MPH to a stop 70 times to have generated 11.2 kWh of regen.

[Piotrsko]

How about one really long downhill? Thinking of grapevine, whatever they call the Oregon Cali pass on I5, Denver both ways, 50 or 80 either way from Tahoe, (insert your favorite downhill here)

Back in the pre supercharger days, Tesla owners didn't worry about getting back home from Tahoe, just getting there was the issue.

[freebeard]

Siskiyou Pass
Siskiyou Pass is a historic mountain pass in the Siskiyou Mountains of Jackson County. It is the most used pass in the U.S. state of Oregon. The Hudson's Bay Company made the Siskiyou Trail over the pass before pioneers traversed it with their wagons, while still later it evolved into a stage road, a railroad line, and a highway route. The name Siskiyou is believed to be derived from Cree, meaning "bob-tailed horse". Wikipedia

I coasted from the summit to the first Ashland exit in the Superbeetle. It got kinda hairy in the corners.

Road
The pass contains a hazardous stretch of the road starting from Milepost 18 of northbound I-5, which has a steep slope of 6%, negotiating a height of 2,000 feet (610 m) in a short road length of 6 miles (9.7 km). The descent along this highway is considered the most dangerous, particularly on foggy nights when visibility is almost next to nothing. In spite of the hazards involved, 13,000 trucks ply this route every day.

ibid

[Piotrsko]

Afaik, the only bad part is that turn down near the bottom north bound. Couple of turns southbound that get exciting as also the stupid place Cali put the inspection station.

[aerohead]

Originally Posted by redpoint5

I'm saying you either misheard, misunderstood, or the engineer was mistaken about regen adding 40 miles of range to a car that would otherwise have 210 miles of total range.

In whatever the EPA test circuit is, I guarantee ~20% of the energy isn't just being wasted by the brakes.

At any rate, the ability to return 80% of braking energy back into useful work makes "technique" relatively unimportant for EV drivers.



11.2 kWh from all regen / 0.16 kWh from 1 regen braking event from 70 MPH to 0 = 70 braking events.

In other words, during the 250 mile trip in a Bolt, on average, a person would have used regen equivalent to braking from 70 MPH to a stop 70 times to have generated 11.2 kWh of regen.

The engineer is Josh Tavel, Chief Engineer for the BOLT project, Senior Vice President for Energy Storage & Propulsion, General Motors, BS Automotive Engineering & Technology, MS Mechanical Engineering.
-------------------------------------------------------------------------------------
Here's how the numbers work:
1) You begin with an EPA test weight of 3,900-pounds.
2) You drive it at an average 26.6-mph.
3) Every 189.5-seconds you bring the BOLT to a complete halt, at a deceleration rate of approx. 3.3-mph/second.
4) You do this 142.8-times with the 60-kWh pack.
5) You're arresting 2.5628-kW worth of kinetic energy with every stop.
6) With a conversion efficiency capability of 81.1%.
7) Recovering only 94.4 Wh each time.
8) For a total 13,481.89- Wh ( 48,534,806-Joule/second )
9) Or, 13.48189- kWh.
10) Or, 0.40-gallons gasoline-e
11) @ EPA Combined 100-mpg-e
12) = 40-miles.
13) Without regen, you'd be at 160-miles to battery depletion.
14) Regen gets you to 200- miles.
This is only for the 2016-2021 BOLT. No other vehicle.
Please see, CAR and DRIVER, September, 2016, PP.56-59.
You may reach Josh Tavel at, 300 Renaissance Center, Detroit, Michigan, 48265, or call, 800-462-8782.
------------------------------------------------------------------------------------
PS:
Your source may be confused about how EPA 'COMBINED' MPG, Federal Test Procedure is conducted.

[Vman455]

Redpoint5 wasn't asking for the engineer's credentials. He was asking for a citation/source of the specific claim.

Unfortunately, a lot of the press materials for the Bolt's introduction have been scrubbed from Chevrolet's website, but multiple websites' articles from the time report that GM said one-pedal driving would add "about 5% range" in stop-and-go traffic. Using the Bolt's EPA range of 238 miles at introduction, that's 12 miles--not 40.

[freebeard]

Meanwhile, back on topic.... The CyberSquire:


justacarguy.blogspot.com/2024/06/i-am-getting-such-kick-out-of-seeing.html

[Piotrsko]

That picture kinda helps the god awful ugly of the 3/4front view.