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MIT Says We're Overlooking a Near-Term Solution To Diesel Trucking Emissions (arstechnica.com)
An anonymous reader shares a report: Trucking in the US is still driven by diesel-fueled, compression-ignition (CI), internal combustion engines. Daniel Cohn and Leslie Bromberg, a pair of researchers from the Massachusetts Institute of Technology (MIT), published a paper with the Society of Automotive Engineers, suggesting that the best way forward is not to wait for all-electric or hydrogen-powered semis, but to build a plug-in hybrid electric (PHEV) truck with an internal combustion engine/generator that can burn either gasoline or renewable ethanol or methanol. Such a setup preserves the range and affordability that's expected of diesel long-haul trucks while significantly reducing the emissions associated with diesel. To boot, it's a near-term solution; no waiting for battery weight to fall or hydrogen refueling stations to be installed.
A hybrid heavy-duty system isn't a completely novel idea, though a PHEV system has yet to be widely applied and tested in long-haul heavy-duty trucking. A company called Hyliion introduced a hybrid electric-diesel truck in 2017, and San Diego uses a hybrid electric-compressed natural gas bus on its transit system, though the former still grapples with diesel emissions and the latter is not for long-haul use. But there are some distinct problems with all-electric and all-diesel trucks that a hybrid flex-fuel truck could solve. First, freight companies are looking for the cheapest way to transport goods from point A to point B, so expensive electric vehicles don't make short-term economic sense, especially if you're competing with other freight companies using cheaper diesel engines.
A hybrid heavy-duty system isn't a completely novel idea, though a PHEV system has yet to be widely applied and tested in long-haul heavy-duty trucking. A company called Hyliion introduced a hybrid electric-diesel truck in 2017, and San Diego uses a hybrid electric-compressed natural gas bus on its transit system, though the former still grapples with diesel emissions and the latter is not for long-haul use. But there are some distinct problems with all-electric and all-diesel trucks that a hybrid flex-fuel truck could solve. First, freight companies are looking for the cheapest way to transport goods from point A to point B, so expensive electric vehicles don't make short-term economic sense, especially if you're competing with other freight companies using cheaper diesel engines.
There's another kind of heavy diesel-electric vehicle that's been around for decades: diesel locomotives.
I keep wondering how light passenger cars got the hybrid treatment first and long-haul trucks still haven't, when the first successful experience in the field clearly pointed to the latter being the ideal candidate.
"A door is what a dog is perpetually on the wrong side of" - Ogden Nash
Hybrids really shine when they are compared against gasoline engines that do not run full duty. I donâ(TM)t think they compare so well against either diesel or full duty situations. That is, a battery bank isnâ(TM)t going to help much when the truck is spending itâ(TM)s life already at full throttle.
I think you underestimate just how much I just dont care.
How about simply switching them to biodiesel (by law)???
1. Biodiesel is CO2 neutral, but does nothing to reduce particulate pollution.
2. We would need orders of magnitude more biodiesel that is currently produced.
"...However, the private sector does seem to have dipped its toes in hybrid long-haul truck powertrains. In 2017, truck engine maker Cummins announced that it would be developing a 100-mile-range electric semi with a diesel generator on board that could extend the battery range to 300 miles. Last September, the company debuted a hybrid electric and diesel or natural gas powertrain called the PowerDrive. ..." ...and they haven't sold ANY because no serious freight company is willing to a) spend more than they have to on boutique technologies; b) sacrifice both weight capacity and RANGE (these have ranges of 100 miles, or 300 miles with a larger weight sacrifice). A typical truck 7mpg with 300gal tanks has a range of TWO THOUSAND miles and can be filled/turned in about 30 mins. These electric vehicles require 8 hours for full charge.
Sure perhaps some city buses or school buses will use the tech because (apparently) they don't have a bottom line to meet. But real trucking co's are already bled white by new rest hours, requirements to buy new eco-trucks (making the used sale value of their old units plummet), idling units, and a lack of drivers. It's not like there's a surplus of wealth in the business.
And trust me, you don't want to see the cumulative impact of even a 15% increase on transport costs across the supply chain.
-Styopa
Never a good idea to burn food.
What does "most efficient fuel" mean? Fuels are not efficient.
Yeah every year the local newspaper always runs a feel good story about the area kook who converted his VW Microbus to run on discarded cooking oil he collects from the nearby restaurants, but the thing is there are just not enough Chinese takeout joints to supply the entirety of the trucking industry.
Diesel has higher energy density, but that doesn't mean burning it produces less carbon or results in a more efficient engine. Furthermore, the engines proposed in the hybrid solution are not the same "high torque industrial engines". What's "pants-on-head retarded" is your failure to understand the things you comment on.
for this nonsense. Facts and logic? Too complex - we are busy humping with Greta T. here. Get lost!
AC really meant "most energy dense fuel".
Unfortunately, most freight lines in the US aren't electrified. BTW, some locomotives can run both on electric systems and diesel -- i.e. any longer-distance train out of Grand Central in NYC. They run on 750VDC third-rail from Grand Central through upper Manhattan, then start the dlesel when they stop at 125th St/Harlem.
The solution should be massive electrification of freight rail in the US. Regardless of opinions about passenger rail, rail freeight is extremely efficient. Friction from steel wheels on steel rails is much lower than rubber on road, and it can be powered using electricity without lugging fuel, batteries, and/or an engine around.
I didn't find any in TFA. I might as well try to read what our two intrepid professors actually wrote.
What am I saying, this is Slashdot...
This will still increase actual emissions.
Sure, if you're driving a 12 mpg truck, getting a new hybrid with 40 mpg will be better, but it had to be made first.
Replace more trucks and cars with trains, and convert those to electric/hydrogen hybrids instead. High speed passenger/freight trains and medium-speed efficient trains.
And stop ordering Same Day Service or Amazon Prime, you're killing the planet.
Actually, the planet will survive, you won't.
-- Tigger warning: This post may contain tiggers! --
Sure they are. You can measure efficiency many different ways for fuels. Usable energy delivered / mass for example. Also, EROEI is an important one.
Historically [diesel fuel] was also cheaper, though that changed a decade or so ago.
The FUEL ITSELF is still cheaper. But the TAXES are higher.
That's allegedly as a convenient way to collect money from the commercial trucks to pay a proportionate share of the road building/repair costs.
But it's interesting that the state governments didn't jack diesel fuel taxes up so far that the fuel was selling at substantially more per gallon than gasoline until there were a substantial number of diesel cars on the road. (Amazingly enough, the fraction of diesel vs. gasoline cars took a dive back down to "miniscule" starting shortly thereafter.)
Bantam Dominique roosters crow a four-note song. Once you've heard it as "Happy BIRTHday" you can't NOT hear it that way
I'm concerned this focus (not the Ford kind) on cars and trucks ICE regarding pollution sounds more and more like an ideological crusade and/or some kind of misdirection/distraction.
It's like optimising code, you find and go for the hot spot but at some point it's not the hot spot anymore.
Between the lobbyists (farming, container ships, etc), ecological zealots (not the informed reasonable kind), and a bit of a sunny-California tech world somewhat disconnected from the rest of the world (FYI: Solar panels don't work when covered in snow or on cloudy coasts, guys. Neither are electric cars that get garbage range under -30'C practical.)
I fear we're being manipulated/distracted into overlooking some lower hanging fruits for political convenience.
Even even looking at cars we need to take into account that electric cars are actually MORE polluting than traditional ICE cars in regions using coal-fired electric power plants.
That's not counting that they're more polluting to produce and recycle. It generates 8.8 tonnes of CO2 to make an electric car vs 5.6 tonnes for an ICE car, should we take the fight first over making cars last much longer? Keep in mind that's just the CO2 environmental cost for production, nothing said about all the other solvents and the recycling costs.
How can we make sure we're not taken for a ride (pun intended again, sue me :) ) by lobby groups who don't want us to look more closely at the pollution their industry is generating?
Annoying to have to pay some "heavy truck road damage tax" when driving a car that's lighter than what, 70% of cars on the road?
And once a very well intended American trucker came running screaming & flailing at me "NOOOO! DON'T! THAT'S DIESEL FUEL!" as I was about to fill up my 96 Jetta TD in the United States.
I told him "Yeah, it's a diesel car." he just stood there dumbfounded for a good 10 seconds before saying "Really?".
I guess it's pretty rare in some states..?
I find it interesting they are going away from diesel engine instead of embracing its performance and durability and building on tech that is already established.
Same here. Whatever engine they put on the truck, you want lowest cost per mile and lowest emissions per mile. Hopefully those are the same.
I remember hearing about this crazy new idea, hybrid cars, what, 15 years ago? The talk at the time was the same idea. The wheels would always be driven by electric motors. The ICE would recharge the battery and might come on to augment the battery in times of high load. Everyone I talked to assumed there'd be no mechanical linkage from the ICE to the wheels. Turns out that's not how they build hybrids today so what do I know?
Anyway, the theory was that since the ICE only needed to generate electricity to recharge the battery, it could run at an optimal load all the time. No need to run at a wide range of RPMs and range of loads.
So I wonder what's the design center of these rigs? Do they need a mechanical transmission, with all the weight, reliability, and cost that entails? Or could it be more like a diesel/electric locomotive, where my understanding is the diesels generate electricity which drives electric motors.
Solutions must be *VIABLE* or they are not solutions. It is unfortunate, but their cost makes them not an adoptable solution...
When the engine is driving a generator, you can optimise the engine and generator to operate at whatever torque and RPM works best.
Quattuor res in hoc mundo sanctae sunt: libri, liberi, libertas et liberalitas.
The solution should be massive electrification of freight rail in the US. Regardless of opinions about passenger rail, rail freeight is extremely efficient. Friction from steel wheels on steel rails is much lower than rubber on road, and it can be powered using electricity without lugging fuel, batteries, and/or an engine around.
By the way electric rail for passengers could be a viable alternative to private transportation. This need planning and investments. Operations research is less cool than AI for self driving cars but making public transportation more efficient could be a better investment. Unfortunately the urban sprawl that was made viable by the automobile makes difficult for big suburban areas to have good public transport.
One hundred years ago trains were the best form of transportation in my area of north Florida. Rail lines were run every ten miles or so with stops also six to ten miles apart. You only had to walk three or four miles at most to get to one. Even in the early 70's a freight train would go by most nights on the line 400 yds from my home.
You are correct in how difficult it will be to wean people off of owning their own homes and being forced to live on top of each other within walking distance of a rail line. Simply building these high rises and cutting services to outlying areas will cost $trillions and strand more $trillions of real-estate. One way will be to stop permitting new homes and put a 100% estate tax on current ones. As people die the property will be seized and the homes demolished, returning those areas back into forest.
Torque becomes less important when you switch to a hybrid drivetrain. Electric motors can provide a LOT of torque and there is essentially no torque curve; it's all available from 0 RPM to maximum. The limiting factor of torque in a hybrid or EV is usually how fast you can pull power out of the battery rather than what the motors can do. (Ludicrous Mode in some Tesla cars is an exception; they do have to limit the use of full acceleration because of heating of the motors.)