You still get more power with both running than you do from the ICE alone, and I think the S-mode design is all about max power, especially off the line. The thing I find strange is why it doesn't give more assist at higher speeds?

 

If that were true, the assist gauge would be tied to the tach reading, which it is not.

 

Okay, that's what I thought.

So the whole situation makes no sense to me. Consider an identical low-speed situation in S and D. Let's say you're driving at 10MPH instantaneous speed and accelerating at 1MPH/sec. If you're getting more revs in S in that situation then the ICE has more power to give you. It needs less electrical assist. And yet you say that you're seeing more assist on the gauge and that it means more juice is flowing from the battery pack. Where is the extra energy from both the ICE and the battery going, assuming that we're accelerating at the same rate?

 

I think the answer to that is that I'm actually accelerating faster in S than I would be in D for a given throttle position. Since it's throttle-by-wire, the ECU can interpret a given position differently based on the 'gear' setting. It's harder to accelerate slowly in S than it is in D because you have to use less throttle movement.

I haven't done extensive testing with this, so I don't know what the difference in assist levels @ the same acceleration level in S vs. D.

 

The reason is simple -- the battery would be drained to nothing very quickly. As I mentioned earlier, S was designed for high-load situations like going up a big hill, and if assist were used for that, it wouldn't be used very long before power runs out.

 

But the PCU already protects the pack by limiting assist when SoC gets low, why would it need to do anything special in S-mode? It could simply give you assist until SoC drops too low just like it does in D.

And it does give assist at lower speed in S-mode, I just don't get why it cuts out at higher speeds, why is it speed dependent?

 

I believe it simply limits the ratios to a narrower band, which would only affect faster driving. It woudl be similar to disabling the overdrive gear on an automatic to make it over the hill. Since oyu have a little bit of extra torque due to the low ratio, at a lower throttle position, you don't need to press down on it enough to bring about assist.

 

I was in stop and go traffic today and I tried the S mode (it is the recommended driving mode for such an event as per the manual). Althought the assist seems more intense, it does taper off VERY quickly. You will see the assist jump up to about 4 bars of assist and taper off with 2 seconds to 0 assist. At least, that was my observations on my drive home. Does this look like what you got NASA?

Cheers,
Stephane.

 

I'm a little confused about something -- okay, maybe a LOT confused... I thought assist was a good thing, allowing the ICE to rest a little. So, why are we trying to be conservative with assist mode? I understand not wanting to run the battery way, way, way down, but some of what I've read *seems* to imply that assist is bad or negative.

Can someone straighten me out?

Thanks,

Don

 

Hi Don,

I'm only answering the question. I myself aslo think that assist is a good thing and should be used as much as possible. That is my opinion.

Thanks,
Stephane.