Well, yes, that's what I got it for.
I enjoy it greatly, and I also enjoy the magic behind the curtain.
It's hard to know where to begin discussing driving dynamics. There are multiple nuances in play at once, but many of them are hidden or second-order effects. Let's start with the most visible fundamentals emphasized in the sales literature for the Kona and other electrics -- the drive modes or "curves", and regenerative braking. There isn't a whole lot else for a driver to mess with or change! Most electric cars have no gear-ratio shifting, just a single-speed reduction gear from motor to wheels which is quite enough to cover the entire speed range of the vehicle. Electric motors have much wider RPM limits than internal-combustion engines where useful power is produced, including down to a total standstill; they don't have to "idle" at 900 RPM and be carefully kept alive while applying power to a drivetrain. It makes electrics very simple to drive, once you figure out how to shift one to "D" in the first place -- it's a big golf-cart, you have a "go" pedal and a "stop" pedal to control speed, and you just steer it and keep an eye on the guess-o-meter range estimate. There are many ways to describe the experience. This review from Robert Llewellyn and the Fully Charged team, which I've referenced before, is worth a watch for comparison. It presents a nice rundown on the observations of a long roadtrip, where the keyword seems to be "effortless". For the most part, I agree with that. Like most other vehicles, the Kona applies some "creep" in the selected direction when the brake pedal is released from a stop. It's no longer a function of physical automatic-transmission drag, but as described in several references, that old effect became such a natural and expected kinesthetic thing it's now considered a safety feature [updated link]. Under a few circumstances the Kona will remain still with no feet applied to the pedals, notably during a "hill hold" scenario, but usually it will start gently and smoothly moving in D or R. [And making that silly Jetsons-jingle, unless you've pulled the speaker.] Unimpeded drift rate seems to be about 4 mph on the flat. Now we press a pedal, and drivers are given some degree of control over what happens next. |
Those who have been around the hybrid circuit for a while might remember this diagram, from early discussions around the third-generation Prius and my reflections on how it related to the "hybrid system indicator" aka factory-provided sweet-spot meter. For a fully drive-by-wire accelerator pedal, a computer can apply any response curve it wants, a mapping between pedal position and motive force, and that year of Prius introduced three selectable driving modes. Vintages of Prius before then had a single pedal curve but it was fairly "slow-bottom", perhaps most like the "ECO" here than the others, which I rapidly came to appreciate in mine because it allowed a lot of fine control over low-speed electric maneuvering. The curves and drive modes were often misunderstood, however -- selecting any mode in no way changed the maximum power output of the car, it just took a different path reaching that point. |
The most notable feature unique to electric or hybrid drivetrains is the
regenerative braking
capability, where the decelerating car pushes the
motor and produces energy that the battery can store.
Regeneration is probably the single largest factor helping the energy
economy of these vehicles, because stopping two+ tons of car requires
a lot of that.
Even the earliest electrics a century ago had rudimentary regeneration,
because their makers realized the potential [!] energy savings.
Regeneration can be configured as some amount of "drag" feeling when the
accelerator pedal is released, like gearing a step transmission down, and/or
fully integrated with braking so that pressing the normal brake pedal
brings in as much productive regeneration as possible before resorting
to using hydraulic pressure at the wheels at all.
Modern power electronics and control systems have made it all much easier.
Even with all the advances, regenerative braking is also one of the least understood sciences on the road. While researching around for my own EV decision I saw a lot of confusion and misinformation posted in forum threads and even supposedly "informative" articles. In principle, it's simple -- the substantial force of a car slowing to rest is used to spin a "generator" against a controllable load, utilizing the same drive shafts, gear train, and motor that got it going in the first place. But many people still seem to think it's still done "in the brakes" somehow, as though friction is magically turned into electricity captured in a battery. It is often an eye-opener to the public when the simpler reality is explained, along with how the physical brakes get very lightly used and pad/shoe changes will be *very* infrequent as a result. Once they get the concept, then they have to also realize that it's not a 100% capture and replay, there are always losses through the system. |
I have tried about every different combination of the settings, and keep coming back to this -- "eco" curve, and zero regen. First off, having a car dive into a steep slowdown and possibly not show it in the brake lights just because the go-pedal was released seems like utter folly, in these days of ubiquitous aggressive tailgating. Second, being perpetually in a "go-or-slow" scenario, with force always applied one way or the other because finding the "glide" in the middle is too difficult, is simply wasting energy. Momentum is also energy, and gets us down the road like we wanted without us needing to change anything about it! Why mess with that until we have to? Just letting a car roll is the most efficient driving. Porsche agrees with this, and thus their Taycan is one of the few production EVs that doesn't tie regen to the go-pedal at all or allow for the "rubber-band" driving style. |
And here's the other major factor that renders auto-regen levels to somewhere
between academic and annoying.
The service braking in the Kona *is* fully integrated, with regeneration
handling as much of the stopping power requested from the service brake as
possible up to some very generous limit of kilowatts.
That comes with the mild caveat that stopping should be smoothly
applied.
This is easy to prove with a simple test, in mild weather so the pack
has its full acceptance capacity: set regen 0, find somewhere to
do a nice smooth and even stop from a decent speed, preferably downhill,
using only the brake pedal.
Not a panic stop, just a normal well-predicted and controlled deceleration
that brings the car to a safe target point.
Then set Park and get out and feel the brake rotors, front and rear.
That's not where the energy went, plain and simple.
The Kona does it right, like the Prius, and testing the working basics
of that doesn't even need brake
pressure monitors.
After extensive experimentation I dropped my conclusions into a long rant over at Insideevs, in part building on what some other posts had expressed before. Naturally, a few haters came out of the woodwork to try and shoot me down, but whatever. Those are probably the same people spinning their front tires on wet leaves and whining about it, while deluded that they're doing really well at 3.6 mi/kWh consumption. Regeneration has its limits, though. It amounts to a burst of *very* rapid charge into the battery, sometimes more than it can safely handle. A hard stop at speed can easily produce over 300 amps, and while large EV batteries can usually suck that up for a short time, it's far more than most smaller hybrid batteries can accept. Regeneration control has to change dynamically and fast, responding instantly to driver demand, road conditions, and variable limits based on factors like temperature. It also has to know when to quit, such as over complex bumps when forces and currents change too quickly to maintain control of. We can sometimes feel that relinquishing of control as a brief little "sag" in braking force as hydraulics take over, because the ultimate task of the system is to stop the car. What's interesting is that even in regen level 0, a *tiny* bit of energy recapture happens -- all of -2 to -4 kilowatts or so, and vanishes down to 0 on shifting to Neutral. The difference between D and N are indistinguishable by feel, so there's no particular advantage to entering a full "neutral glide" at speed like we sometimes need to do in the Prius. Most of that power trickle seems to go to keeping the 12V system alive, as its voltage reliably shoots back up to that excessive 14.8 float in the process. If the car's speed is above some minimal level like 2 mph, one can freely shift between D and N and back without having to press the brake pedal. It's only at a full stop that stepping on the brake is needed to move to D, which I suppose is a reasonable assumption such that an inadvertant tap on the button doesn't unexpectedly *start* the car moving. But if it's already moving forward, that was the driver's intent so no lurchy additional brake-press is needed then. Knowing this is important to me because there are several circumstances where shifting to N on the fly is useful. One is to deliberately use the friction brakes to slow, usually to clean rust off the rotors -- a couple hundred feet of gentle hydraulic-only braking takes care of it, and then it's back into D. [Moving to N *during* a braking event immediately disables regeneration in just about any hybrid/electric system, and is the easy way to reproduce that "hydraulic takeover" transition to learn what it feels like.] I also usually shift to N at stoplights and such -- it allows sitting there and watching the rearview to know when to pulse the brake lights toward someone approaching from the rear, without having the car try to creep forward in bursts. It also makes for a much smoother stop over the last couple of MPH. Being able to do all that without looking or fumbling was the main reason for the shift button mod to make it easier to find. Overall, once all these things are worked out and gotten used to at the muscle-memory level, the experience of driving is very smooth and pleasant. I don't really notice the road/tire noise that others complain about because the windows are usually open some way, my hands are locked into a very stable position on the wheel crossbar, and I'm relaxed and one with the machine just like always. And pulling 5.5 mi/kWh on a summertime mix of local/highway, I might add -- that's about like high-fifties MPG in a Prius. The *only* differences I really notice on getting back into the Prius are the longer expanse of dash-top in front of me, and a slightly heavier steering feel. Oh, and of course that "old car smell". |
Eking out economy
Driver assistance sort of isn't
This particular car is the "SEL" lower-end trim, and doesn't have some of
the extra comfort/safety stuff included.
That's fine, I didn't really want that stuff so it was appropriate.
It does have a "lane keep" system that uses camera vision to try and stay
centered on the road, and in the more assistive modes gently nudges the
steering back toward center unless you're signaling for a lane change.
It's amusing for all of about 20 minutes, and then we realize what all of
the bugs in it are.
The major one is when an off-ramp lane opens to the right before a highway
exit.
The LKA dutifully tries to re-center itself in that rapidly widening
"lane", and guess what?
Now you're heading straight for the gore area and off-ramp divider.
Once the lines get too far apart it gives up and cuts out, but the stupid
deflection toward disaster has already happened.
It also seems to be no good when lines are converging, changing its little
icon to show "inactive" until a lane re-forms to something that looks
normal to the little camera in the windshield.
At other times it can be self-negotiating a gentle curve nicely, and then
just give up for no obvious reason and leave the car to dive off the
roadway without so much as the warning beeps it's supposed to issue.
Not only is it no substitute for a watchful human, the human actually has
to fight the damn thing sometimes.
Between LKA and generic cruise and confusing "auto-hold" settings and clumsy features of the paddles, all of this feels more like "driver interference" than "driver assistance" to me. LKA might be a useful brief reminder to use once in a while if I'm poking at the GPS, which is probably my worst window of attention vulnerability. I'll give it all an honest go and try to understand how some people might like to use these features, but within about ten minutes I'm like "my airplane" and go back to actually driving the vehicle. At this point I can often tell just by looking at other cars and their motion dynamics when their drivers are trying to rely on these overly-automated nanny systems -- that so often get it wrong where real-world safety is concerned. Most notable is those fucking "auto-follow" radar cruise controls, which I am constantly having to yuppie-button off my ass because their supposedly "safe" systems still ride too close. As much as things may have advanced recently, if you want to spin the tales of people sleeping inside moving Teslas as "progress", we're stll a long way from fully autonomous vehicles that can deal with all possible conditions. It's not even clear that people want today's partial solutions, if they are still called upon to intervene when needed. A telling indictment of that human factor comes from a section starting around 05:40 in this "Autoline" interview where a senior figure *in the industry* of autonomous-vehicle research learned that his wife turned *off* all the safety crap in her new car because it was just too annoying. At least she was able to; that may not be true in their next car. Tesla is making impressive strides in the field of neural networks, on both hardware and machine-learning fronts, but after learning more about their approach in some very long videos from their "Autonomy Day" presentation a while back I still have serious doubts that golden "level 5" target. Their approach is essentially a data-intensive rote-learning model, which is highly unlikely to reach a point where it competently handles human nuance any time soon. Failure fallback is also too slow for most traffic situations. I dropped some fairly deep thoughts about this into a forum post in the Tesla area, which I'm sure the fanboiz over there view as me simply pooping on their lawn. Still, there seems to be growing agreement that true "autonomy" especially in populated areas is going to need a lot of direct infrastructure support, and possibly be kept separated from where human drivers are still doing their thing ... at least until the very last human driver is forcibly removed from the loop. Good luck getting that to happen. |
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