"Automatic" engine braking

Here we go again!

 

So you've still not managed to reach the condition you're being contrary about - when the car can no longer produce drag by regeneration due to full battery, so must either produce engine drag or nothing. So you did not manage to produce a relevant result.

If you've never managed to fill your battery you have no relevant first-hand knowledge to agree with or contradict the observations of those who have experienced full batteries.

I don't understand why you can't grasp the logic here.

 

Well, if you value facts over ego, you need to clean up your post. It has erroneous assertions and assumptions. Surely you know that the overnight charge does not charge the traction battery to 100% SOC. In your post you are making the presumption that you can hear engine braking, even on an engine design with variable valve timing and with CVT in the place of a normal transmission.

A good way to set your path forward is to abandon the attempt to override everyone else. After all, there were errors in the posts of all the other threads you set up to argue about your pet peeve.

.... Or is this the AI posting again?

 

He's using the common tool of the conspiracy theory. He challenges you to prove him wrong, but when you present him with proof he declares you a liar or mistaken. How does he know that you are wrong? Easy, he disagrees with you.

 

In the hope of increasing knowledge, rather than ignoring it, do we have data on how 'full' 100% is? Not in the sense of SoC, but in terms of how much regen power is available, compared to lower SoC? Is it set at a level where you still have normal regen, or is it already diminished? I've never spotted it diminished from the dash display, but that's not very conclusive.

I believe this should be clearly visible in Techstream etc, so maybe there's already been G4 observations.

One more observation - the Predictive EV Drive that the USA doesn't have is keen to shed charge initially, before starting its auto switching to HV mode. (So if your journey starts on a motorway it won't switch to HV immediately if at 100%, but use EV down to 80 or 90%) That could be about increasing regen ability, or it could just be about battery life.

 

This BC trip must be the one Paul referred to in post #56 of his earlier thread on the same topic (a good thread to review for any newcomer wondering about this one).

For clarity, when Paul refers to "the claim of automatic engine braking", he specifically means the claim that the car's ability to spin the engine in fuel-cut mode to resist forward motion is not exclusively used when B is selected, but can also be observed when D is selected and the traction battery is too full to accept more regen.

Drivers who have already observed that happening, many capturing it on OBD-II instruments, may be puzzled at so much attention to the question whether it happens or not. But then, Paul has a Prime, with its much larger battery, so the "battery too full to accept more regen" condition is much less often reached in everyday driving.

Paul conducted an earlier test, in less-demanding terrain, and reported it in post #53 of that earlier thread. In advance of that test, he had been advised (posts #38, #39, and #50) of ways to conduct that test that would give it the best verifiability and credibility, in case he found himself reporting a result at odds with what others have experienced and often captured on instruments.

He used none of that advice in that earlier test, choosing instead to report with no quantitative data,

An alert reader will spot (credit where credit is due, KMO did spot) that Paul's report itself says regen braking continued all the way down, which is a dead giveaway that the necessary "battery too full to accept regen" condition never was reached, and therefore the claim Paul meant to test did not get tested.

That led to the anticipation around Paul's planned BC trip, in which he would "have a good opportunity for a do-over, and may be able to do it over with more attention to the reproducibility and credibility of his work."

Which brings us to this thread, in which he has made that trip, again without observing any of the earlier advice on how to conduct an effective test, relying not on instruments but on "windows down, audio system off, and I surely would have heard".

From this test, Paul reports again having "experienced 'braking' of a sort, but it wasn't engine braking, it was regenerative braking", and so reveals that in this test, also, the necessary condition of "battery too full to accept regen" was never reached, and the claim Paul wanted to test was not tested.

This is worth drilling into just a little further. If the car is on a steep downgrade, speed being held by regen braking, and then the battery becomes too full to accept more regen, at that moment, without any change by the driver, something different must start happening.

Regen braking at that moment will cease. If the car applies no other source of rolling resistance instead (such as engine braking), then the car's speed must begin to substantially pick up as soon as the resistance from regen ceases.

That second alternative is a claim Paul has, in fact, made, in an even earlier thread:

Paul may be convinced that's what happens when the battery can accept no more regen, and others may be convinced that engine braking is what happens then, but one thing that cannot happen then is that the car just keeps going down the hill the way it was while regen was happening.

Paul's test here has not reported that he noticed engine braking, and also has not reported that regen ceased and the car's speed then began taking off. Those are two alternative claims about what could happen when the battery's regen capacity is filled, but because that capacity didn't get filled, neither of those claims got tested.

 

Skipped.

 

it would be helpful to know how much charge the battery had when beginning descent, and how much at the bottom of the hill, and how your speed changed from top to bottom