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Comment by bArray | Hacker News Reader

> VTNA has made some improvements to the truck's diesel powertrain as well. It has switched from a six-wave piston to a seven-wave piston, and there are smaller needle control valves in the fuel injectors. There are smaller pistons for the D13 turbodiesel engine, with longer connecting rods and shorter pistons to "create better tolerances to fit in the cylinder to reduce that friction inside the cylinder," Stadler told me. And Michelin has developed new lower-rolling resistance tires for the VNL that further improve efficiency.

Well done to them. 10% fuel savings is massive for something that is already quite efficient.

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Hopefully the improvements in efficiency are real. I've had trouble trusting the numbers coming from car companies after the emissions scandles

This isn't a consumer car situation. They're not trying to hit some paper efficiency number that matters environmentally in aggregate but is hard for any individual with highly variable driving, pricing etc to really notice. As the article also emphasizes this is about cold hard money in real world constant heavy usage across the entire country since this is long haul. These vehicles are going over 100k miles a year, which at their fuel economy translates to something like 14000-16000 gallons of diesel per year, and in turn at an average price of ~$4/gallon [0] is like $50k-60k, per year, just in fuel. Individual truckers and companies will absolutely notice whether they're adding 5000 to 6000 dollars to their net income per vehicle, or not.

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0: https://www.eia.gov/petroleum/gasdiesel/

If you had a VW TDI, you got better real world fuel efficiency than the EPA fuel efficiency. And lower CO2 emissions. And all you had to do was wiggle the steering wheel ever.

Yes, yes, some fraud. Yes, yes, NOx emissions. But the fuel efficiency numbers were better than published.

10% fuel savings only matters if you never have to think about maintenance costs. Same with the replacement cost for tires, although to me the tire efficiency is a bigger multiplier since they aren't replaced as often as the fuel tanks are topped off.

Truckers can easily spend thousands a day on fuel. They’ll take it.

You have a good argument, but the exaggerated numbers hurt your case. $5 per gallon and 5 gallons per miles are high/low estimates. At this rate, fuel costs $1 per mile. Are you saying they "easily" drive thousands of miles in a day? I'd hope that 2000 mile days (the minimum for "thousands") are really rare.

It's also not possible at legal speed limits in the US. The highest legal speed on any public road in the US is a short 85mph section on one toll road in Texas. The more common 80 mph only gets you to 1920 miles per 24h without stops.

They use way more fuel in hilly areas.

Your numbers are for an individual truck driver.

A trucking company is also a trucker.

Relatedly, it's not uncommon for trucks to have sleeper cabs and multiple drivers so that the truck is on the move close to 24 hours a day. Using the provided numbers and ordinary highway speeds, that leads to a fuel cost of more than $1000/day. Whether "thousands" has to mean strictly more than $2000 is being somewhat pedantic.

Yes, exactly. Long haul drivers operate as 2 or 3 driver teams. They specially high value cargo. Those things stay moving.

Also 5mpg is high for pulling an unawrodynamic load.

Diesel is well over $5/gal on the west coast right now, and flirted with $7/gal last fall

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