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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"?

Yep. As it is all controlled by software, this is being done today already.

Drove a Volkswagen E-Up. It had an Eco and an Eco+ Mode. Those seemed to just limit the acceleration, and for a bus this seems mandatory.

The Nissan Leaf defaults to Eco mode and the pedal is very unresponsive. Click Eco Mode off and it'll give you whiplash.

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?

Probably just changes the pedal mapping.

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.

EVs have no 'shift points' or changing gear ratios.

Maybe or maybe not.

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.

On gasoline (as opposed to diesel) engines, it actually used to mechanically open a butterfly valve that controlled the air intake (the throttle).

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.

source: i develop software for buses.

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.

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.

Hmmmmmmm, an interesting question!

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.

Oh God, this. There's nothing more obnoxious as a cyclist than a full face-blast of gritty bus exhaust when it takes off in front of you.

Not to mention noxious.

I found two-stroke motor scooters worse. If only because of the fact that those can drive on some cycleways here.

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.

I enjoy the quietness of the bus from the outside on the street. They don’t noise pollute, especially when taking off.

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:

https://en.wikipedia.org/wiki/Jerk_(physics)

Yup! It's because I watched https://www.youtube.com/watch?v=DMKcO-T5Y4o

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.