16,000 just for Shenzen. They've made the full switch to EV this year for a city of ~14 million inhab. It's crazy.
For comparison, Paris (I should say the Parisian region) plans to have only 2,000 zero missions buses by 2025! And that official numbers includes NGV... So much talk about the transition (remember the "Paris Agreement"?) and yet, so little progress...
I'd say they are making a comeback because of climate/air pollution reasons, but also because the energy competition between batteries and oil is starting to balance out. The energy density stored in oil is far greater than the primitive batteries used 100 years ago, which allowed for much larger ranges.
However, as batteries have gotten far better, now batteries are starting to rival oil as an energy source on its parameters and economics.
City driving is indeed the best environment for EVs simply for the air pollution reasons, never mind the added benefits of lower speeds and lower ranges.
I like the discussion at the end about the difficulties on delivering the busses long distance, and the lack of chargers big enough to recharge them. If the Tesla Semi actually launches at some point, perhaps that will change and we will get city-to-city electric busses too. Battery ranges should improve to the point where that becomes practical over the next few years too.
What a great market that would be for Waymo. Predictable routes of mostly highway driving would be right up their alley.
With electric buses, at least, you can put the chargers at end point stations, which is a cost but one bussing agencies can handle. Also, they cost much less than the overhead wires electric trolley buses currently use.
One idea I've read is to use those overhead wires for BEV busses, but only on certain segments. Most bus lines loop through a central area, so could charge along a section of a few blocks that feature the overhead wires.
Wire attachment is a big problem even for bus line me that are fully overhead. Before the buses had batteries, a detachment often required shutting down the road and bringing out a big truck to reattach the bus.
Seattle used to run dual gas/electric (not really hybrids since no battery) in the downtown tunnel by having them attach going in and Unattach going out. Great when it worked, but it often didn’t, so they just use cleaner emission buses now instead.
To me buses and truck market seems niche as compared to personal cars for companies looking to build electric tech to drive them. Number of state departments and businesses willing to pay for electric vehicle are fewer compared to electric car customers.
Trucks and busses often follow centrally planned routes without much deviation, they're too large to be sent down narrow lanes or poorly maintained roads, and the people who buy them are ready to spend a six-figure sum.
Some companies might have autonomous tech that's a good match for those constraints, despite the much smaller market.
And airlines are niche compared to mass market cars too, but they're still a good business!
One thing I think most people don't appreciate is that the switch to self-driving cars will transform America into a mostly-transit society. Once you don't need a car to live from day to day, you sell it. Then you take a self-driving Lyft from your house to the bus depot, train station, or airport.
The market for self-driving busses between cities will grow alongside the market for self-driving cars within cities.
The prediction is that ride-hailing taxis will be ubiquitous and cheap once we have self-driving cars. Companies will be able to flood the city streets with them once they are purely a capital expenditure and they don't have to pay human drivers.
If self-driving taxis are ubiquitous enough, there could be very little wait time between hailing a taxi from an app on your smartphone and the taxi arriving at your location.
At some price point, it will stop making sense to spend $20,000-$30,000 to buy a car. And you won't have to pay for insurance or gas or wear-and-tear or parking. The car could be out making money instead of being parked 22 hours a day.
Businesses and apartments and home developers will stop building parking spaces and parking lots once self-driving taxis hit a sufficient threshold.
Finally, cars will solve transit's "last mile" problem. Instead of paying for a taxi from home to work, you can pay for a taxi from home to the Light Rail station.
You can't get people to ride buses now, often for reasons like fear of crime, not wanting to associate with "those people", perceived low status. So somehow a driver less bus is going to be _more_ appealing? A big box full of strangers with no supervision or authority figure? Lord of the Flies on Wheels? I think this is going to be a hard sell.
Indeed. BYD's electric vehicle production is heavily supported by Chinese subsidies and cuts in these subsidies have had a big impact on profits. Its stock has been steadily declining since the announcement earlier this year.
Compression ignition is being used in gasoline by Mazda. Their Skyactiv-X technology uses the spark to control when the compression ignites (like fake-dieseling), and Skyactiv-X uses "dieseling" without spark to run the engine at low loads.
I just got a new Mazda with a Skyactiv engine. I am really happy with the performance, but wanted to see about adding a turbo. Seems like it's not a good idea to add a turbo to an engine with 13:1 compression. The engine can actually run at 14:1, but they lowered it for the US.
It's really interesting to see Mazda take a lead in engine design. Once one would have expected this more from Honda.
However, it's not all good. Apparently direct injection gasoline engines emit more particulates than conventional gasoline engines. This may be a manageable problem and new regulations are supposedly in effect from 2017 in the US (unless they got caught in Trumps emissions control rollback), but that does not clean up the several years of cars with direct injection before now.
Well, ask LA how that is working out [1]. While I applaud the effort it is not without its problems. I always thought that we should have moved to electrify school buses. while the initial expense is high it would have protected systems from fluctuations in fuel prices that have put a real hurt on them at times.
plus it would get kid used to the idea of an EV world and not having to sit on buses idling for too long
Just because America cannot make something work, doesn't mean it cannot work in other countries. Especially in the public sector context, which is full of mismanagement in America.
I don't think the parent comment was making that kind of point. The referenced article was talking about problems that LA officials were seeing at (and with the vehicles produced by) the BYD plant that is the subject of this post's Ars Technica article. And I can vouch for that; as I detailed in another comment, I often ride BYD buses that are old enough to be in the scope of the LA Times article, and there are issues.
I expect this electric vehicle maker will get their act together with time!
Side-note: a barrel of oil gives a fixed amount of gasoline and diesel fuel, and that's hard to change [1]. A given refinery could slightly change the amounts, but not much, and that's billions in investments. Even if you replaced diesel vehicles by electric ones, the diesel fuel will be burned somewhere else.
Indeed, but—since you mentioned it—there are a lot of missed opportunities in electrifying short range passenger ferries. Many ferries might only sail for 20 minutes and remain docked for a while where they could be recharged. Even on a busy ferry routes, a natural gas powered boats might actually make a lot more sense then a diesel powered one. The only real use for a diesel engine now might be for long distance cargo vessels, cross ocean passenger ferries, and very very huge fishing trawlers (although I would very much like to see the big trawlers vanish into history).
I don't see diesel being phased out for agriculture or construction equipment anytime soon, usually too remote from the grid and they can't afford charging downtime. However, I welcome replacing what we can with electric. It's a slightly specious argument that simply because we can't replace all use of diesel there isn't a point to replace some usage. City buses are a major use, and are located in a much worse spot for pollution, at least as it affects people's health. How is less fossil fuels being used a bad thing, there is no possible way we can replace all uses in one fell stroke.
The article doesn't make it clear - but "elsewhere" seems like it would clearly be better than urban busses. They assert that even in areas where grid electricity to charge the busses comes entirely from fossil fuels, there is less pollution produced - presumably because it is somewhat easier to make a fossil fuel plant cleaner at scale than 100s of busses. Fossil fuel plants could be any of natural gas (very clean), coal or.. oil, which in this case is something resembling diesel, or the diesel constituents of crude.
The title is (of course) fairly misleading - while we've got electric boats and semis it is unlikely that long haul transport for either will be electric any time soon. But - at least they are away from urban areas, for the most part.
You can essentialy use the batteries of electric vehicles as energy storage. Most passenger vehicles don't need to run at noon when everybody is at work and surplus solar is available. They don't need to run at night when people sleep, electricity demand is low and wind whirls. Buses can also be scheduled for loading during these periods as they can run 200 km on a charge and transport capacity is adjusted according to demand - only a fraction of the fleet operates during low demand periods mentioned above, the rest can sit and charge. Long haul transport can run on plug in hybrids using HCCI internal combustion engines and/or gas turbines powered by diesel/gasoline or ideally DME/LPG. This can be all tuned using economics. Coal needs miners for extraction and is dirty to burn. Gen III+ and IV nuclear and geothermal are much cleaner and safer alternatives for base load.
Burning it elsewhere might not help when it comes to CO2 emissions (though if it ends up being burned in a much more efficient engine/powerplan, at least you get more useful work out of it), but it can help a lot when it comes to health[1]. Diesel is particularly dirty, and burning it in densely populated areas should definitely be phased out. Long-haul trucking might make sense, but buses and garbage trucks should at the very least run on hybrid natural gas, until they are electric.
>Diesel is particularly dirty, and burning it in densely populated areas should definitely be phased out.
The latest EU diesel standards for passenger cars are actually on par with the gasoline standards. Don't know what the standards are for heavy trucks though.
> The latest EU diesel standards for passenger cars are actually on par with the gasoline standards. Don't know what the standards are for heavy trucks though.
Can we trust any of the big automotive manufacturers to actually meet those standards without cheating?
> The automotive industry says it has cleaned up its act. But this week the European Union’s executive branch, the European Commission, revealed it has discovered a whole new form of cheating – this time on CO2 emission tests.
The 2016 scandal concerned air pollution tests on diesel vehicles, where automakers were using so-called ‘defeat devices’ during tests to make the cars seem like they were emitting less pollution. Now, the carmakers are accused of doing the opposite – artificially inflating the level of carbon emissions produced by new cars coming onto the market now.
Why would automakers want their cars to look more emissions-intensive than they are? Because a new EU law will require automakers to reduce their fleet average CO2 emissions by 15% by 2025 and 30% by 2030 – based on 2021 levels.
They've gamed the tests quite a bit over the years. Yet so far, even after all the scrutiny, VW is the only one that was actually caught cheating. VW is probably enjoying the muddy message everywhere that "everyone does it" but so far only VW has actually been found to be cheating.
Heavy duty are supposedly cleaner (per unit of fuel) both on paper (standards) and in reality, because manufacturers don't shy away from exposing business customers to the maintenance burden of exhaust treatment systems. But trucking is a border-crossing low-margin business, corners will be cut at every opportunity.
I wonder if there's data on the difference between engines with factory settings, and vehicles that have been modified to roll coal. My hometown had a number of people change their trucks to roll coal and it would get noticeably hazy in busy intersections
I used to work at a 4 wheel drive shop in a previous life- there are likely more modified diesel trucks out there than you think. The idiots that purposely modify trucks to 'roll coal' are a minority compared to owners who have bypassed pollution controls for increased reliability and fuel economy. A truck with the EGR bypassed or DPF removed spews more particulate than stock, but this isn't visually apparent. Most of the smoke from rolling coal is unburned fuel in the exhaust gas, this phenomenon seemed to be mainly restricted to younger people, especially oil field workers.
I know this is anecdata, but at least in CO, UT, WY area there are more modified trucks than what is immediately apparent, since often a truck w/ bypassed emissions equipment isn't heavily cosmetically modified.
I live in a small Texas town outside of Austin. I think my diesel pickup is the only unmodified one here. It's really that common. The exhaust after-treatment and DPF systems are fairly complex and most owners just take 'em out. There's emissions inspections in this county, but diesel vehicles are conveniently exempt.
A bit late to the reply, but mostly it's perception: when the urea-injection exhaust-aftertreament systems first came out in 2013 or so there were a few reliability issues that dealers didn't do a good job of fixing. It's much improved now and my truck hasn't had any issues at all.
And, I'm sad to say, some folks just like the whole "rolling coal" thing and the ability to put out huge plumes of black smoke.
That's not even something I would argue. I guess my real question would be "what is the difference between a car that passes emissions tests and a car that is modified about 30 minutes after an emissions test"
There are a fair amount of people who will actively pollute because you asked/told them not to, and I wonder if they have a significant effect on the environment
You get a fixed ratio of distillates, but you can use cracking to convert heavier distillates into lighter distillates. The majority of the world's gasoline is cracked rather than distilled. Refineries in the US produce a substantially different mix of products than refineries in Europe and Asia because of different market demands (including significantly lower demand for diesel).
Changing that production mix is capital-intensive, but everything in the petrochemical business is capital-intensive. US refineries are having to substantially change their operations because of the increasing production of unconventional oil, which yields a very different mix of distillates compared to conventional crude.
The big win is that diesel is nasty and nobody enjoys breathing in diesel exhaust. Most Americans don't realize how awful diesel exhaust is because almost nobody drives them, so you aren't exposed to it as a pedestrian or person living near a well-used road.
It doesn't combat overall pollution, but it does improve the quality of life for people living in urban areas.
That's incorrect. Refineries have crackers (catalytic cracking units) that can be used to tune the yield. It varies seasonably at the same refinery.
From your own citation:
"Separation processes, such as distillation, dewaxing, and deasphalting make use of the differences in the physical properties of crude oil components to separate groups of hydrocarbon compounds or inorganic impurities, whereas conversion processes cause chemical changes in the hydrocarbon composition of crude oils. For example, Fluid Catalytic Cracking process breaks chemical bonds in long-chain alkanes to produce shorter chain alkanes to produce gasoline from higher boiling gas oil fractions"
Soooo we should just keep using diesel and stop longterm electrification trends because "someone's going to burn it"?
This is fud.
The point of electrification is to get a path towards sustainability. If it means demand for barrels of oil decreases, or in the most extreme, all that extra diesel becomes a stranded asset, all the better (unless you're a refinery owner).
Gasoline powered vehicles are also replaced and Big Oil can invest in electric vehicle companies and renewables as they diminish the output to account for the lower demand.
Also, diesel engines can be converted to DME which is cleaner and offers a path for CO2 recycling. DME/electric plug-in hybrids is a solution mainly for trucks and shipping because they can automatically switch to electric near populated areas and use the ICE for extensive range.
I figure the mid-term goal should be to end up only refining oil for jet fuel and petrochemicals. So either the products have to be converted (as others have explained) or burned in a power plant. We will need more energy for all those electric vehicles after all, so more oil burning power plant may be needed in the transition.
Long term goal is of course to not extract oil at all, but some products will be hard to replace without radical new technologies.
Article misses big point: This is not about electric buses. Electric buses have been a thing in many cities for decades. Vancouver BC has run electric buses since at least the early 90s when I rode them to school. This is about battery-powered buses. Running on electricity and running on internal batteries are two very different things.
Edit: Vancouver has been running electric buses since 1948.
Gillig, in Fremont, also makes electric buses in the US. Cummins (formerly Cummins Diesel), from Columbus, OH, makes the electric powertrain. Cummins owns a battery company in the UK.
It's nice that BYD is using lithium iron phosphate batteries. Much safer than ordinary lithium-iron batteries. You really don't want a bus-sized battery fire.
The bus batteries aren't usually as huge as you'd expect them, I've seen buses with just double the size of a Tesla S battery. It's because they just recharge often, they don't need long range, a single circle is usually 30km max.
What is more efficient than a diesel engine for long-distance economy cruising? A big European family car like a Mercedes E220 CDI estate can cover more than 1000 kilometres on a single tank of fuel at highway speed, all while carrying 5 passengers and their luggage.
Electric is more efficient/cleaner than that. You might not get the same range, but realistically, few people drive that far without stopping (biological needs, taking a break, etc), so that provides time for fast-charging.
Biological needs and taking a break don't necessitate 20-30 minutes every 300 miles, though.
I think this is the only advantage combustion engines still have. It seems to be a big one. To refill a tank takes less than 10 minutes, with the range stated by parent.
I'd like to add that when you aren't rich enough to own a specialized vehicle for every task you have to cater more toward the edge cases, for most people that interior size and/or higher passenger/cargo capacity than they need on a daily basis. Likewise nobody's gonna make their only car something with a 250mi range and a mandatory 45min break if you're going farther than that because it makes a 150mi round trip something you have to actively plan for (because starting on 50% will be a pain in the butt vs a 10min delay with a liquid fueled vehicle).
That's when car hire companies come into the mix. If you're not commuting those distances regularly, chances are you've planned the long distance in advance.
Even if you have planned it in advance, car rentals get expensive quickly, especially if you want something more than a passenger car.
SUV/Pickup rentals are often >$500/week, AND the agreement will claim that I'm not supposed to take it off road, so if I'd like to go out to some hiking trailhead along the way, I'm totally uninsured if anything happens on that dirt road.
Adding $1000 to the cost of one of my yearly vacations adds up to a lot of money over the life of a car.
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On that same note, long trips are quite common for many Americans who don't commute those distances. My daily commute is 4 miles each way, I could bike it if the road had better infrastructure for it.
On at least 2 weekends a month, I'm driving 200+ mi each way, and my destinations typically do not have charging infrastructure (or paved parking lots). I know lots of people who do the same for their various outdoor hobbies.
I suppose I forgot how spread out the US is. Europe is just as spread out, but they have a decent train network. I'm from Australia, and our cities are a lot more centralised, that everything is either within 100km, or greater than about 500km. Well, except for a couple of cities on the east coast, most notably Sydney to Newcastle. Where I am though, there's basically not major centres in that mid region.
"Biological needs and taking a break don't necessitate 20-30 minutes every 300 miles, though."
They really should. If you don't need to stop for a loo break after ~4 hours (at 75mph), you're not drinking properly. And you really should get out of your seat for 20-30 minutes after 4 hours non-stop driving.
There are cool electric buses running in the streets of Minsk, Belarus since a couple of years. IIRC, they have nikel-iron batteries with have limited capacity but good lifetime, and they recharge quickly. An electric bus runs for 30-40 min from terminus to terminus, then charges for 10 min from trolley power lines.
Pretty neat, especially considering that nickel and iron are extracted in nearby Russia and are much cheaper than lithium.
Interesting for this one it says: buses will be equipped with Chinese supercondensers that proved to operate very well in Bulgaria and China. Re-charging will not take more than 7 minutes.
Diesel will be with us for a very long time yet, even if all diesel buses were to be swapped for electric.
-- Diesel locomotives (train engines) and many ships use diesel generators to power electric motors -- this setup is useful for applications where high torque is required at low RPMs (even down to 0 RPM)
-- Many grid support power plants use diesel generators (especially for emergency backup)
-- Diesel-powered trucks, tractors, and heavy equipment
The first place to phase it out of is densely populated areas, because of all the particulate matter pollution which is particularly bad for people's health:
Ships not only use diesel for generators but for propulsion in general; many engines found in recreational mid and large motoryachts are basically truck diesel engines adapted for a harsher maritime environment. Volvo Penta, Detroits, Caterpillar are very popular. Marine diesel is taxed differently and is somewhat cheaper than truck diesel (and has a different color due to a different dye added; marine diesel is red, truck diesel is yellow). Diesel is also safer than gasoline in terms of accidental ignition and explosion since the ingnition temperature is much higher than gasoline. Diesel fuel flash points vary between 52 to 96C (126 to 205F)
>Diesel locomotives (train engines) and many ships use diesel generators to power electric motors -- this setup is useful for applications where high torque is required at low RPMs (even down to 0 RPM)
Few ships are diesel electric. It's inherently fairly inefficient compared to mechanical power transmission. Diesel electric is mostly used in locomotives and heavy mining equipment where a mechanical drive-train would be overly complex or inconvenient to package (imagine the drive-train for a freight locomotive) but the machine enough driving that hydraulics is too inefficient (whereas something like a mining shovel doesn't do much driving and the market).
>Diesel-powered trucks, tractors, and heavy equipment
For stuff that's small enough to transport on a semi and doesn't need to go highway speed it's really hard to beat hydraulics for low cost and low cost of ownership. A slightly more efficient drive-train doesn't really make it far up the important features list when you're gonna be pushing dirt and your maintenance schedule and how hard on equipment your employees are dominates your longer term cost of ownership. Indoor stuff will go more electric but it's been electric for awhile, it'll just get better/lighter.
>Military vehicles
Not gonna happen anytime soon except some specialty applications (small inshore subs come to mind, SDVs are already electric). Military stuff needs to stay light for a variety of reasons and the last thing they need are a bunch of volatile batteries that need to be protected (whereas a fuel tank of diesel can act like armor to some extent).
US tanks use turbine, not Diesel engines. More military could have used those, especially as infra-red signature of turbines is lower, but it is chicken and egg problem. The present market is small and for tanks a turbine initially developed for helicopters were adopted. For other vehicles entirely new development is necessary. And it is very costly.
Can you provide a source for this? It has been my understanding that turbines had more of an infra-red signature due to the hot exhaust and high mass flow.
Exhaust from a Diesel has much brighter IR signature as it’s exhaust particles are black bodies that radiates and scatter IR very effectively. As turbine generate much cleaner exhaust of molecules that does not radiate much in IR on their own, it’s IR signature is lower despite higher temperature and more exhaust mass. This is a rare example when pollution is bad both for environment and military applications.
I do not have references. I learned it from a buddy whom I trust.
At least in northern Europe, Diesel engines are critical to the agricultural industry. Considering some farmers are still using 40 year-old tractors around here, I doubt the Diesel engines will go away any time soon.
But one of the advantages of Diesel engines are that they aren't really that picky when it comes to fuel. I don't think the engines are going anywhere, but we're probably going to see more and more non-fossil Diesel alternatives being used in the future.
Seems like there'd be significant savings in having multiple municipalities or even entire states coordinate their bus orders.
It seems especially silly to order a custom looking bus because this would obviously raise the price of replacement parts. Is this part of why old buses always look like crap? Cities don't want to pay the crazy cost of replacing a custom part that is clearly damaged or worn out.
City buses are not the only large vehicles that typically are manufactured after purchase. Firetrucks, concrete trucks, and many limousines are the same. If you're going to build it by hand on demand anyway, why not add value by building exactly what the customer wants? So long as designs stay within an engineering envelope, which envelope can be pretty broad when we're talking about something as simple as an electric bus, it doesn't add much cost to accommodate the customer's particular needs. If those needs extend to having a particular number of body panels in stock for future repairs, that's fine. Nothing mechanical in the drivetrain would be custom (although I suppose the batteries might be, apparently they have a guarantee).
They don't mention it in the article but do these big buses use regenerative braking? Seems like a no-brainer to add on considering all the starts and stops a bus does, but maybe it's not worth the extra cost for fixed route operation?
I believe most electric buses do: adding regenerative braking to electric vehicles requires little additional hardware (the electric motors can act as generators, etc.), so it is certainly cost-effective.
I believe they do use regenerative braking, yes. I say that because I ride BYD busses on a regular basis, and (especially on older models, which are not as smooth) you can feel (what I think is) the jerk of regenerative braking kicking on.
I regularly ride on buses that were made by BYD. I have been for the past year (or so), and have noticed a few things:
• The front destination signs seem to always have had problems. In addition to the technical problem (that is, problems with the signs themselves), there is also a weird build issue on some of the busses: The bus has a front panel above the windshield, part of which (the part in front of the sign) is transparent. For some reason, some buses got an unusually-small transparent area, with a regular-size sign display, which meant that the test was always partially-unreadable. I assume that different display hardware was supposed to be used?
• The acceleration and braking dynamics are _very_ different compared to diesel (and even diesel-hybrid) busses: Because so much torque is available immediately when moving from a stop, it is very easy to jerk passengers around. Similarly, the busses like to move into regenerative braking immediately the foot is lifted off of the accelerator, often making another jerk. It can be difficult to adjust (as a driver) if you're moving between multiple different types of busses, during a week or even during a shift.
Both of the above issues are things that can be rectified, although I wonder how much modification would be needed to get smoother acceleration and braking. And regardless, the time needed for the bus to be out of service (to implement any necessary modifications) is still time where the bus's value is continuing to depreciate.
Besides the negative acceleration/deceleration issues, are there any features of the BYD buses that you really enjoy? I imagine they are very quiet and don't smell like exhaust. Just wondering if those nice qualities improve the bus riding experience at all.
I think the biggest plus point is, if you are seated, and facing in the direction of travel, then the acceleration/deceleration issue doesn't apply. You then have an experience where you get to where you need to go much faster, because the bus is better able to keep up with traffic.
Also, regarding two of your points:
> I imagine they are very quiet…
Actually, the answer may surprise you! My experience has been that the electric buses can be louder than their diesel equivalents. I expect this is because that, for diesel buses, the noisiest components are all in one place (normally the very back of the bus) with soundproofing material in place between the engine compartment and you). Electric busses (at least the ones I've experienced) have motors spread all around you, with less sound-dampening material in the way.
> …and don't smell like exhaust.
Exhaust smell is not something I've particularly noticed from the remaining diesel busses. I expect that is due to three reasons: (1) The emissions standards placed on California-registered diesel vehicles; (2) the maintenance regime in place; (3) the fact that, when I leave the bus, I end up going towards the front (and away from the exhaust pipe). Although, in places that I've experienced which don't have (1) and (2), you are right!
From having lived right next to a bus stop on a 24hour route I can safely say the new London electric buses are dramatically quieter.
And when commuting on a bicycle, not having to stand in traffic behind a diesel bus is a welcome relief. Possibly life changing to some degree. The fumes from old buses are absolutely disgusting.
In the summer, stopping next to a diesel bus when on a bike you often get hit by the heat of the blowing engine cooling fan. Which strangely often feels both refreshing and heat stroke inducing at the same time. Have you noticed anything about this issue with electrics?
> Actually, the answer may surprise you! My experience has been that the electric buses can be louder than their diesel equivalents.
Like a lot of things this will depend on the make and model. In San Francisco, Muni bought a bunch of Skoda electric trolleys in the early 2000s. They were extremely loud compared to their predecessors and their replacements.
Muni also bought some Cummins powered diesel buses around the same time. Those too were extremely loud (roughly 90 dB at not-so-far-away distances), but 90 dB was loud enough to gain some traction with Cummins and Neoplan. Still, these buses were far less grating to me than the old two-stroke diesels (it's a beautiful whine from a mechanical standpoint, but not something I want to hear a few times an hour driving past my house).
> Exhaust smell is not something I've particularly noticed from the remaining diesel busses.
California is well off in this regard, I can't remember seeing more than one or two trucks belching smoke. Even in Europe I don't remember the interior of the buses smelling much of diesel exhaust -- and they shouldn't, you really don't want to expose your passengers to exhaust fumes.
Cuba was an interesting contrast as they burn some of the lowest grade diesel fuel around (and most things are diesel these days). The smell of high sulfur diesel is unlike anything I've smelled before.
Interesting about the acceleration and braking UX... that experience is exactly what makes electric passenger cars feel sporty and responsive, but I can see why you don't want that for municipal buses.
Then again, the "gas pedal" is basically a skeuomorphism dating back to when it mechanically opened up a gas valve... it's all drive by wire, so, "fix it in software"?
What makes limited acceleration more economic? Are there efficiency losses that are dependent on the time it takes to convert x joule from electrochemical storage to inertia?
It is more about the shift points in the transmission. Your engine is most efficient at around 90% throttle and "low" rpm. Your car is more fuel efficient are highway speeds then city street speeds (aerodynamic factors are insignificant at low speeds). The result is that engineers can trade acceleration for efficiency by changing the shift points, and you don't realize that the throttle is nearly wide open since the car isn't accelerating very hard at the low rpms.
Of course the engineers who design eco mode probably know more about how to do this than I do. I know they mess with shift points, it wouldn't surprise me if they did other things too.
Some EVs have a transmission - while it isn't strictly required (which is why others do not) for best acceleration you need one. If there is a transmission this is a shift point.
Of course EVs have completely different operating parameters. The rest of my post was respect to a internal combustion engine.
Some EVs have a transmission, yes. My Volt has a planetary gear set in order to share traction with the ICE. But that's not a pure EV.
But what they don't generally have, unless they are conversions from ICE cars, is changing gear ratios. Torque is mostly constant across all RPMs in an EV, so there's not really a need for one.
You also kill the batteries in shorter amount time if you do not limit the acceleration. The habbit of pressing the accelaration to the bottom will drain lots of power from the battery. It also encourages reckless/sporty driving. Best way to do this is on passenger cars is to have an eco/sport switch. On a passenger bus or truck you don't need a sport switch, since those vehicles are meant to be driven responsibily.
Yes. Resistive losses in the motor and inverter are proportional to the current squared (I^2). Accelerating hard requires more current so 2x acceleration incurs 4x resistive loss. It's not a huge effect in most applications, but it does make a difference.
Tesla introduced a "chill" driving mode for this very reason. It makes acceleration and braking (regen) much smoother and many owners speak highly of it.
I was taught to drive like that in The Netherlands by my driving instructor. It is much safer (especially with deliberate bumps to slow you down in a neighbourhood where children play), saves you fuel, and it saves you your brakes. It does cost you a little bit time and this can add up if it means you miss a traffic light due to that but it could also mean that you still get a green light. So in the end, the loss is very little to nothing.
At least in the US, the route display HW is ordered and installed separately from the bus itself. That's so transit operators can maintain consistent looks/route number/destination displays/destination codes (that the bus driver types in) even as they mix different models of buses into the fleet.
Re: acceleration and braking - it's funny that you call it out as jerking passengers around, as that's exactly what engineers and physicists call it too:
Honestly, as a bus passenger I'm always shocked what a poor experience we get for our fares in general. For example, in my city they've been buying Novabus diesel vehicles, which are quite possibly the shakiest ride I've ever experienced. The rattling is both uncomfortable and abominably loud.
I'm used to seeing the tail bus-number screens being dead more often than not, although I can't say if that's our new Novabuses or not.
And these vehicles are priced into the high six figures.
So I'm not surprised that electrics have a similar disinterest in passenger comfort when it comes to the typically-strong acceleration and breaking of electric vehicles.
I imagine it's a dogfood situation - the users aren't the ones making the buying decisions.
>The acceleration and braking dynamics are _very_ different compared to diesel (and even diesel-hybrid) busses: Because so much torque is available immediately when moving from a stop, it is very easy to jerk passengers around. Similarly, the busses like to move into regenerative braking immediately the foot is lifted off of the accelerator, often making another jerk. It can be difficult to adjust (as a driver) if you're moving between multiple different types of busses, during a week or even during a shift.
>Both of the above issues are things that can be rectified, although I wonder how much modification would be needed to get smoother acceleration and braking. And regardless, the time needed for the bus to be out of service (to implement any necessary modifications) is still time where the bus's value is continuing to depreciate.
This is just a teething issue. City buses are geared to top out at low highway speeds, like 50-65mph. Current diesel drive-trains have more than enough go power to send passengers flying but they don't because they're mature technology. Pretty soon they'll figure out how to put the power down in a way that doesn't toss people around.
> This is just a teething issue. City buses are geared to top out at low highway speeds, like 50-65mph. Current diesel drive-trains have more than enough go power to send passengers flying but they don't because they're mature technology. Pretty soon they'll figure out how to put the power down in a way that doesn't toss people around.
Electric buses are hardly new or immature technology. The batteries are new, sure, but the motors and their control bits are not. Some vehicles are going to be easier to drive smoothly than others. Take a look at the Van Hool (diesel) buses that Alameda County and Washington DC bought, there are plenty of complaints about how they're jerky by design.
regarding the digital signage: BYD probably doesn't make the signs or even choose them. it is usually chosen by the purchaser, based on compatibility with whatever on-board computer and software they've chosen. they should, however, be customizing the body to fit the customer's aftermarket hardware because every bus order is bespoke.
I've ridden on BYD electrc buses for about 8 years, and on hybrids for a few years before. I live in China, which has a lot of buses, and BYD have a lot of market share. To share some of my observations with your observations:
Decoration signs/asthetics - Poor client requirement. It isn't hard to say how large a display should be and cut the shape. I found the design of the front windshield interesting. Very curved, looks oldskool. Cute.
Traffic in Chinese cities is pretty start-stop, with buses kings of the road. No one will try to cut-off a bus. You're right there's a lot of torque.
Drivers should not be switching type of bus more than once ever (per change in model). Lines replaced here are replaced overnight: all buses serving the route yesterday replaced with new buses today. The drivers do need time to get used to the new power supply, and also the new balance of weight bus bus now has (diesel and wheel-base applicable too).
When passengers and driver have gotten used to it, the ride is very smooth.
For charging: Peak time is rush hour. Buses going about 150km perhaps over 4ish hour time slots (urban). During the day they charge (relay team, one takes on lower frequency scheduling while the other charges, on destination another goes off-charge while the returning bus charges). When all on a full-charge and in evening rush-hour 3-4 hours everything is sweet.
Charging and usage-patterns shouldn't be a problem for a bus.
I don't have a lot of faith in BYD busses actually working correctly. Proterra seems like the most solid design around, and looking on LinkedIn, it seems like they picked up a lot of people who worked at Tesla when things were going better over there.
Care to expand on why? It seems they are working correctly as they make over 500,000 vehicles a year whilst Proterra are claiming 375 since inception. [1]
The thing we really need is inductive charging for the busses at each stop, and at each stoplight. Then you don't need to carry the heavy batteries around.
But agree that hybrids seem like an interesting option. Electrifying half the route may be much much easier than electrifying 100%, and would let you run small-battery electric busses all day.
I find it interesting that this article doesn't mention the Albuquerque Rapid Transit (ART) debacle. The political mess surrounding ART is far from entirely due to BYD, but ART placed what I believe is the largest order so far for 60-foot electric buses from BYD. The comment about driving the 60-foot units long distances with generators is the way that they've delivered the first several units.
The situation has decayed to the point that Albuquerque has considered trying to terminate the contract. The first several units delivered have had significant quality problems, and recently the city's inspector general released a report suggesting that audits showing the buses comply with Buy America regulations were falsified and they are potentially ineligible for expected federal grants. Workers in the city transportation department have voiced concerns about many of the components on the buses being apparently manufactured in China and lacking US certification marks and, in some cases, English documentation. Delivery on the remaining buses in the order continues to move farther back.
The City went into the project understanding that the 60-foot buses were a new product for BYD, and even expects federal funding from a grant program for employing new technologies. But at this point BYD is a significant part of the near complete failure of a major project built around their product. It seems worth mentioning that their customers are not all happy.
To ART's credit, the city IG reports that massive pressure for the city forced BYD to begin delivering units earlier than they otherwise would have (but still significantly behind schedule).
Part of the grant program the city is using to fund the project is that the city will send one or two units to an FTA facility for inspection and testing. That testing is expected to result in the FTA certifying the model for future non-experimental federal grant programs, but most people involved in the ART project now have significant doubts about whether or not BYD will be able to deliver units that pass this process.
Years ago I bought a diesel because it was more efficient (and more expensive) than gasoline and emitted less nitrogen oxide. Now diesel vehicles are seen as worse than gas engine vehicles. But switching isn't a problem the people who were early diesel adopters did it for a reason; efficiency so really electric vehicles are the new diesel.
I hate seeing this conversation about diesel when we should be having this discussion about gasoline.
Gasoline engines have lesser thermal efficiency and lesser torque potential than diesel engines. If you're going to get rid of one or the other, get rid of gasoline vehicles.
Diesel engines have a longer stroke, cooler combustion, more flexibility with air/fuel ratios, extreme wear tolerance, lower rotational speeds, and cost the same with similar complexity to gasoline engines. They are also more economical in practice because their extra low-end torque gives them (arguably) a drivability advantage which lends itself to increased MPG.
They are superior to gasoline engines in every way. And because they can run with air/fuel ratios anywhere from 10:1 all the way to 60:1 they can easily run a mutitude of different fuel's with only minor software adjustments.
So please, stop shitting on diesel. It's ignorant to the fact that you probably drive a gasoline powered car that does more damage to the environment per gallon of fuel burned than a diesel bus.
They are superior in every way except the one that matters: diesels are much dirtier than gasoline engines, especially with respect to particulate emissions.
Diesels are only good for limited purposes, like buses and trucks, that need the higher efficiency.
Second paper only considers fine-size (<20 nm) particulates (and not larger sizes like 100nm+) of direct injection cars, and is a bit misleading by comparing six cars to a single carefully-selected diesel car with particulate filter. Further, in reality here in a London, people are cutting open their Diesel particulate filters to avoid cost of replacing clogged filters and still passing MOT exhaust tests, which apparently don’t/can’t check for filter tampering.
Third paper is way back in 2002 and considers only cars, not heavy trucks and buses, which are way worse in urban settings.
As jeffwass notes, diesel is better at CO2 emissions. But in California, particulate emissions matter more, especially in SoCal, which is prone to inversions that trap particulate pollution.
I don't disagree with your points here, other than the MOT changed in May to include inspection of the DPF system if fitted (on 2006 onwards vehicles) , including checking for one which has been cut open. Obviously not foolproof, but at least its a start - if the DPF is missing, it's a fail now.
Please cut this diesel apologist Bullshit! Your defense of diesel entirely ignores exhaust and emissions.
Sorry to be rude but this is a very personal and emotional topic to me and you’ve really pissed me off by saying “They are superior to gasoline engines in every way.” You apparently aren’t living in a city where the poor-sighted decision was made to promote Diesel engines over gasoline for marginally better CO2 metrics, and now get to breathe air that exceeds annual EU pollution limits in mere days.
Diesel is terrible in urban settings. It’s dirty as hell. I have no idea where you live but Diesel engines are entirely on their own choking the streets of London with their particulates and NoX exhaust. Gasoline engines are much cleaner by comparison.
I’ve gotten bronchitis several times in the past few years. I’ve finally tracked it down to the nox fumes, primarily from buses and heavy trucks where it’s a very noticeable sharp smell. I’ve gotten a bit better by avoiding high streets whenever possible, and I’m also proactively going up to drivers in idling diesel cars and asking them to cut the engine. It’s been estimated that 10k people are dying a year in London alone from effects of the exhaust!!
Correlation of coughing fits with noticing an earlier exposure to walking through a NOx cloud. The NOx smell is unmistakable once you identify it.
The tricky part is that there’s usually a delay of a few hours between exposure and cough attack. Intentionally avoiding high streets has helped for me. I still get coughing fits but not as many full on cases.
Diesel particulates (aka: soot) comes from unburned fuel during the combustion process due to insufficient heat in the combustion chamber. This can be reduced with software that eases into the throttle instead of literally translating the input from the gas pedal into throttle input. Applying the throttle slower results in more complete fuel burn. Here in the USA when you crank up your injectors to create the black cloud of smoke it's called "rolling coal." It's how you get more power out of a diesel engine without changing anything else. Just pour in more fuel. Because they don't have butterfly valves in the intake or throttle plates, diesel engines usually operate at or in excess of 100% volumetric efficiency. So while a 2.0L gas engine will consume 900cc of air at partial throttle, a diesel engine WILL ALMOST ALWAYS consume approximately it's displacement worth of air on an intake stroke. So a 2.0L diesel, even at part throttle, is consuming around 2.0L (or more) of air per intake stroke.
So to limit particulates, add a throttle limiter that limits throttle changes to a certain speed where the temperature of combustion increases proportionate to the fuel being injected.
You can also reduce soot output by filtering the fuel. You can refine diesel until you're blue in the face, but the fact of the matter is you get to a point where the cost of refining it isn't worth the benefit coming out of the tail pipe.
Not to mention the soot falls back to Earth and doesn't stay in the atmosphere as long as you think it does. So much of that black cloud is getting washed into your sewers when it rains.
You've found a bug in your code and you want to throw it all out and start over?
My vested interest comes as a result of enjoying vehicles. I am as much a gearhead as I am a hacker, and seeing something so efficient, so powerful, and so useful that LITERALLY built the industrialized world by powering 18 wheeled trucks and trains and container ships get crapped on by people who don't even know what the difference between their Corolla and a diesel engine actually are.
I owned a 1990 CTD Dodge W350 truck and that thing would do a brakestand from a 3rd gear clutch drop AT IDLE... with 300k miles on the clock. Find me a V8 gasser that can do that and pull a trailer through the Kangamangus at 20+mpg.
The trade off is drive-ability and throttle feel. The vehicle will feel sluggish, but it won't "roll coal" if you ease into the throttle. This can be proven by gasp actually driving a diesel powered vehicle and a) stomping on the gas pedal and b) easing into the gas pedal.
The more common solution it diesel particulate filters in-line of the exhaust pipe that cause the soot to completely burn off. This is a trade-off because the DPF requires maintenance. Some systems even go so far as to implement aggressive exhaust gas recycling, pumping already burned exhaust back into the intake to be burned again.
Lithium Iron batteries makes sense. The cobalt used in anode of common Lithium Ion batteries, 60% of the worlds cobolt is mined in Congo. Cobolt is conflict mineral
https://en.wikipedia.org/wiki/Cobalt
It makes sense to use Lithium Iron batteries in a bus because these batteries can take more recharge cycles 2000-8000 instead of the normal 500 recharge cycles of Lithium Cobolt.
I'd love to know how they are holding up (I have to assume that the limited deployment is effectively a trial by Transport for London to see how well they work) if anyone knows of any updates on those?
Based on the statistics for London buses (about 490 million KM driven a year by 9616 buses = about 51,000KM a year, or about 32,000 miles a year source: https://tfl.gov.uk/corporate/publications-and-reports/buses-... for distance and https://data.london.gov.uk/dataset/number-buses-type-bus-lon... for number of buses) it would seem that the average daily distance for a bus would likely be somewhere in the 80-120 miles a day range depending on how many days a year a bus is driven (that range is for 365 days to 250 days a year). At 80-125 miles a day, that seems like it is screaming out for electrification right now. It would seem that it is totally within the reach of current technology. The BYD K9 has an advertised range of 155 miles.
The sooner diesel buses (and trucks) leave urban areas like London the better. The rancid stench and taste of diesel fumes that hit you is disgusting, not to mention that some diesel vehicles are outrageously loud too. Diesel is literally killing us.
How long before some valley city council mandates public transport and outlaws private company transport like the Google bus. Because, you know, for the greater good!
The conservatives (meaning disliking change) on these city councils also tend to dislike public transit; they want to live like they imagined it in the 1970s with everybody driving their personal car on uncrossed freeways long distances between their homes, work, and commercial districts.
Even their desire to stick it to the techies will not overcome their love of car-first, or sometimes car-only, policies.
Bosch in Germany used to have a big research facility dedicated to Diesel engines and their control systems. They stopped that and converted the facility to research and develop various control systems for electrical cars. So Diesel days are numbered indeed.
Diesel is dying in Europe because you can’t enter a lot of cities in an older diesel car. In a few years it’ll be any diesel car.
Green tech is a universal political point in Europe, at least north, Western Europe, and car companies aren’t stupid. It takes time to alter production, but they are getting there, as demands keep increasing.
In Norway half the cars sold are electric. I personally own a petrol car, but I doubt I’ll replace it with a fossil.
I was shocked to see public opinion change overnight on this issue because some German auto manufacturer cheated on their tests. This should motivate people to fight corruption, not fuels.
Properly maintained EURO4+ vehicles are just fine. Yes, they product some more particulates and NOx, but if you look up the specifics in absolute values, the difference is essentially trivial.
Replacing diesel with gasoline in commercial vehicles will increase transportation prices at least 30-40%, my guess would be much higher. It simply won't happen. Commercial electric vehicles are a dream (or a financial nightmare, depending on your perspective) at this point.
Are diesel's days limited in light personal transport vehicles? Maybe, depending on politics. Are trucks, buses etc going electric anytime soon? Not really.
For public transport, most people and most city councils will choose to improve their services (like more routes, more buses per line etc) and not to shrink just to use the latest bus-sized gadget.
You've highlighted an important point: The long tail of old technology. If I recall, for some city in Europe, it was businesses running old vehicles that were crying out for exceptions on the rules to ban the older diesel vehicles. The vehicles which are driving basically all day. Not great policy if they are granting all those exceptions.
BYD busses don't look anything special, yes they are electric but you can get those from a lot of manufacturers. Also they are only partially low floor.
More interesting is the Aptis by Alstom, still more or less a prototype but its design is really something innovative because it increases the room in the bus and it is 100% low floor.
I've lived in the New York City metropolitan area, New Jersey, for most of my life. Buses play a major role here for public transportation. There are bus routes to NYC from all over New Jersey, of public and private chartered variety. One of the major benefits of these buses is that they offer affordable transportation, subsidized by taxes. Replacing these buses with electric ones in an economically viable way is what will keep electric fleet off the roads for a long time yet. While I wish that every diesel bus on the road would be replaced immediately by an electric one, I see this taking at least another 20 years.
The adoption of electric busses over CNG doesn’t make a whole lot sense to me? In a perfect world going electric would be great - but it seems like CNG offers the right balance of lower fuel cost and cleaner emissions while maintaining fleet efficiency (no long charge times).
Would love to hear why electric buses actually have the lead over CNG if you take out the pure “feel good” factor of electric
Also, the article seems to acknowledge that city driving is the best application for electric vehicles.
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