Big Electric Trucks

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remy_martian

· #3 · 2 mo ago

Tesla is comparing its 0.36 aero to standard, non-faired, diesel rigs. More Musk koolaide for fanboys and stock speculators to drink.

The other electric semi trucks use lowering suspensions, cab-trailer fairings, front grill shutters and other tricks to get the Cd down. This was part of a US government program called SuperTruck in 2016...so much for innovation, lol.

What sim s/w are you using on that wheeled shoebox?

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brian_

· #4 · 2 mo ago

prawn said:
Crazy that the Tesla semi is allegedly 0.36, compared to avg 0.70 of other rigs. I think there's more to it than just Cd, not my wheelhouse.

It would be crazy if it were true. The 0.70 value is not for comparable (modern, slope-nose, highway service) diesel trucks.

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cricketo

· #5 · 2 mo ago

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brian_ said:
It would be crazy if it were true. The 0.70 value is not for comparable (modern, slope-nose, highway service) diesel trucks.

I can't find any examples of "modern slope-nose" with the numbers. All I found is this :

here is a graphic from a "study" :

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remy_martian

· #6 · 2 mo ago

It's also hilarious that the infamous video of the Semi towing a trailer of Jersey Barriers is NOT a closed trailer like the ones in @cricketo's sketch here.

A flatbed trailer 4 feet off the ground has much LOWER drag than an enclosed one that's 13 feet off the ground.

Both Nature and Cd abhors a vacuum at the tail of a vehicle and pressure recovery is almost impossible behind a tall box. Nobody picked up on this that I know of...

Those Jerseys also tamed turbulent airflow behind the cab back to laminar...

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brian_

· #7 · 2 mo ago

cricketo said:
I can't find any examples of "modern slope-nose" with the numbers. All I found is this :

here is a graphic from a "study" :

View attachment 136502

With no idea of the trucks used in the first one, all cabovers in the second one, no idea of what era of trucks were used, and no source... that's sort of interesting. The first one appears, based on a Google image search, to be a scenario from a student's problem in a textbook. A reasonable guess might be that at a typical modern North American truck might be like "c" in the second graphic (tall rectangular trailer, with cab-top air deflector)... at a Cd of 0.521.

Tesla does a good job of aerodynamics, but I'm not giving them credit for unfounded claims of being twice as good as an unspecified and unlikely mystery truck.

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smokeycanadian

· #8 · 2 mo ago

I'm sure this isn't exactly new to everyone but still..here..

US approves California plan requiring half of heavy duty trucks be EV by 2035

The U.S. Environmental Protection Agency (EPA) on Friday said it was approving California's plans to require a rising number of zero-emission heavy-duty trucks as the state pushes to cut pollution.

www.reuters.com

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kennybobby

Discussion Starter · #9 · 2 mo ago

2

Some screenshots from Dana video for some big truck EV parts; can anyone read that big red banner?

Automotive tire Product Automotive design Motor vehicle Engineering

i guess they aren't too worried about the inductance of the long-ass motor phase wires

Tire Wheel Vehicle Automotive tire Tread

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brian_

· #10 · 2 mo ago

smokeycanadian said:
I'm sure this isn't exactly new to everyone but still..here..

US approves California plan requiring half of heavy duty trucks be EV by 2035

The U.S. Environmental Protection Agency (EPA) on Friday said it was approving California's plans to require a rising number of zero-emission heavy-duty trucks as the state pushes to cut pollution.

www.reuters.com

The target - 50% of new trucks by 12 years from now - doesn't seem wildly unreasonable to me, because it include medium-duty trucks and many local and regional delivery and vocational applications are well-suited to battery-electric operation... even if long-haul highway tractors are not. And "new" is a very important criterion (also found in requirements for light vehicles) - no one has to retire anything to meet the requirement.

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brian_

· #11 · 2 mo ago

kennybobby said:
Some screenshots from Dana video for some big truck EV parts; can anyone read that big red banner?
View attachment 136599

Interesting. Dana acquired a majority share in TM4 to set up their joint effort... and Technologies M4 Inc. (now TM4) started in Quebec. According to their history, TM4 set up a partnership with a Chinese company in 2012, so perhaps all of their motors are built in China.

By the way, the same history shows SME establishing manufacturing in China in 2007; SME is (now as part of Dana TM4) the supplier of HyPer systems sold through NetGain (the HyPer 9 and associated controller, used in many DIY conversions).

kennybobby said:
i guess they aren't too worried about the inductance of the long-ass motor phase wires
View attachment 136600

Apparently not!

One reason for the length is that the motor is mounted on a beam axle so it moves and the cables need room to flex... although they're still twice as long as they need to be for that purpose.

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remy_martian

· #12 · 2 mo ago

That cable inductance is a mice-nuts impedance at the electrical frequency the motor rotates at and relative to the winding inductance.

You're probably thinking of the inverter switching frequency, but its ultimate job is to produce three "low" frequency sine waves that are each 120 degrees out of phase of the adjacent phase. If anything, the motor phase cables are LPFs for the high frequency switching currents.

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ganesgupta6

· #13 · 23 d ago (Edited)

Hey there, thanks for sharing about Work Truck Week! It's great to see more attention given to big electric trucks. With technological advancements, electric trucks are becoming more practical and efficient for work purposes. I'm excited to see what new models and features are being showcased at the event. For those interested in purchasing an electric truck, truckexporter.co.uk offers a variety of options to choose from. Their website provides detailed information on each model and their capabilities.

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