PHEV's virtual electric overdrive.

[Grigou]

OK

So, with both methods it's less of 10 kW at 0 km/h.

The question is : how much at other speeds ?

 

[anko]

It wouldn't make a lot of sense if it was more. But when I compare the reading of the Power meter (which doesn't include power needed for charging) with the reading from my OBDII scanner the difference between the two seems to be about the same amount (at constant speed, that is).

Of course, regen charge current can be way higher, but that is a different story.

 

[Grigou]

It wouldn't make a lot of sense if it was more.

Why ?
One could imagine that the current is limited at 0 kph for some reasons (noise, heat, smell ...).

But when I compare the reading of the Power meter (which doesn't include power needed for charging) with the reading from my OBDII scanner the difference between the two seems to be about the same amount (at constant speed, that is).

OK

Of course, regen charge current can be way higher, but that is a different story.

Way higher are definitely appropriate words for at least 45 kW ... What a pity that we have only 8 kW in Charge mode ! But there is certainly a good reason for that (battery's life probably...).

 

[gwatpe]

My PHEV has maxxed out on the REGEN with 60kW. Can only be seen on the INFO-TRIP screen.

A shame the generator power is not shown somewhere.

 

[Kim]

I had to go downhill quite steep and for quite a few miles a few days ago. Needed B5 all the way.
But after a short time, force of regen was reduced by the car, so I had to add additional brake force by stepping on the brake peddal.
I don't think, the car allowed more than 25-30kW of regen for a longer period,
which of course makes sense with only a 12 kWh pack on board.

 

[anko]

I had to go downhill quite steep and for quite a few miles a few days ago. Needed B5 all the way.
But after a short time, force of regen was reduced by the car, so I had to add additional brake force by stepping on the brake peddal.
I don't think, the car allowed more than 25-30kW of regen for a longer period,
which of course makes sense with only a 12 kWh pack on board.

What was the SOC at the beginning / at the end of this adventure? We know regen does not work quite as well on a (near) full battery. And it makes sense too. Could be related to this, could be related to something else as well. I remember driving down the Col du Galibier in the French Alps last summer. Started with my SOC well below 0 ( :mrgreen: ) and ended up with way more than 50%. Can't remember any fading effect.

 

[anko]

It wouldn't make a lot of sense if it was more.

Why ?
One could imagine that the current is limited at 0 kph for some reasons (noise, heat, smell ...).

Haha. It would be interesting to learn it was because of the smell. It took Mitsu in the Netherlands about 3/4 of a year to even acknowledge that little issue. :lol:

What a pity that we have only 8 kW in Charge mode ! But there is certainly a good reason for that (battery's life probably...).

Why would you want more? Personally I don't see a reason why we would need more (unless it allowed for a further increase of efficiency). Instead, I would like to see that we had 8 kW all the time (within limitations of the engine, of course) and not only under ideal driving conditions. As soon as driving conditions become a little bit more demanding (compared to driving solo on a flat road at constant speed with no head wind) the charge current reduces and so does our ability to maintain a decent SOC.

 

[Grigou]

I had to go downhill quite steep and for quite a few miles a few days ago. Needed B5 all the way.
But after a short time, force of regen was reduced by the car, so I had to add additional brake force by stepping on the brake peddal.
I don't think, the car allowed more than 25-30kW of regen for a longer period,
which of course makes sense with only a 12 kWh pack on board.

What was the SOC at the beginning / at the end of this adventure? We know regen does not work quite as well on a (near) full battery. And it makes sense too. Could be related to this, could be related to something else as well. I remember driving down the Col du Galibier in the French Alps last summer. Started with my SOC well below 0 ( :mrgreen: ) and ended up with way more than 50%. Can't remember any fading effect.

Having stay often in Savoy I drive quite often for long uphill and downhill and I have sometimes this fading effect, and sometimes not.
All I can say right now, is that the correlation with the SOC is not obvious (at least if we stay under 12 bars or so). It could be a simple question of time and strength of regen, or a combination of time, strength, SOC and temperature ...
Not obvious indeed.

Why would you want more? Personally I don't see a reason why we would need more (unless it allowed for a further increase of efficiency)...

Simply to be able to recharge, let's say in 20 minutes, at the same level as we recharge actually in 40 minutes ... (having 15 kW instead 8 for example would be great). The actual slow recharging demands a lot of anticipation wich could be avoided by a more "instantaneous" recharge. The more the time for recharging would be short, the more the versatility of driving would be wide IMHO.
And like you, the second reason is to increase the efficiency of the ICE when charging

 

[anko]

. The actual slow recharging demands a lot of anticipation wich could be avoided by a more "instantaneous" recharge. The more the time for recharging would be short, the more the versatility of driving would be wide IMHO.

You are aware you can also take off with an empty battery (and recharge while driving, if you must), aren't you?

 

[Grigou]

Of course I am aware of that, but why this question ?

I must admit that I do not see the connection between it and my assertion

May be a little one : taking off with an empty battery and with a better recharge capacity (ie 15 kW) could be more interesting in some circumstances (short trip to a nearby town).

 

[anko]

When I drive to the office, my battery is empty upon arrival. I cannot recharge at the office, but when I want to go home, I just go. Why would I first recharge it before taking off?

I have seen a lot of discussions on how pre heating requires proper planning, but this is the first time I am in a discussion about planning to allow for pre-charging. Apart from the fact that it is relatively inefficient, IMHO.

 

[Grigou]

When I drive to the office, my battery is empty upon arrival. I cannot recharge at the office, but when I want to go home, I just go. Why would I first recharge it before taking off?

It is another scenario, isn't it ? I spoke of reaching a nearby town in travel (without possibility to plug the car here and there). And then, driving in EV in this town. For me it makes sense to use the Charge mode (mainly when driving in parallel mode) if I know that I will drive in a town.

I have seen a lot of discussions on how pre heating requires proper planning, but this is the first time I am in a discussion about planning to allow for pre-charging. Apart from the fact that it is relatively inefficient, IMHO.

There is a beginning to everything
For the case I have decribed above (planning to drive in a town), I think that it is relatively efficient to use Charge in parallel mode before reaching the town.
Maybe I'am wrong, and in this case I would be happy if you could demonstrate it

 

[anko]

I see my mistake now. Earlier you mentioned your efforts to find out charge current at 0 km/h. That sort of stuck with me. Because of that, I really thought you were referring to charing while parked before taking off. My bad .

 

[Grigou]

... and I see mine too : I spoke of 40 minutes for both cases (at 0 kph and in travel to reach a town).
40' was not a good choice for my demo, it was a bit confusing !

Anyway, it's not a problem

I was surprised and sad not to agree with you this time

 

[anko]

Glad we fixed that :lol:

 

[Trex]

Now I wanted to bump this thread as I have seen it mentioned how the PHEV revs too high at highway speeds here recently.

Please read this thread from the start.

 

[STS134]

Now I wanted to bump this thread as I have seen it mentioned how the PHEV revs too high at highway speeds here recently.

Please read this thread from the start.

Well one of the things that was mentioned is that at > 78 mph, the ICE runs continuously. It is also essentially direct drive (with the clutch in the GKN multimode etransmission engaged), AND is optimized to produce max power at 90 mph. Which is great, if you want to produce max power. If not, it's literally wasting a lot of energy just forcing the engine to turn that quickly (at 3700 rpm) when it doesn't need to. One of my other cars has a CVT and keeps the engine at 3700 rpm at 90 mph, IF you select "S" (or sport) mode, which is supposed to be for ability to accelerate quickly. Put it in "D" (regular drive) mode and it'll hold the engine at 2400 rpm UNLESS you are accelerating or climbing. Now on the other hand, we don't have the losses associated with sending mechanical power through a complex gearbox, but I think the inefficiencies caused by running the engine at so high an RPM outweigh this. I measured around 22.7 mpg on a recent trip during which I drove at high speed for a lot of the way.

 

[anko]

Well one of the things that was mentioned is that at > 78 mph, the ICE runs continuously. It is also essentially direct drive (with the clutch in the GKN multimode etransmission engaged), AND is optimized to produce max power at 90 mph. Which is great, if you want to produce max power. If not, it's literally wasting a lot of energy just forcing the engine to turn that quickly (at 3700 rpm) when it doesn't need to. One of my other cars has a CVT and keeps the engine at 3700 rpm at 90 mph, IF you select "S" (or sport) mode, which is supposed to be for ability to accelerate quickly. Put it in "D" (regular drive) mode and it'll hold the engine at 2400 rpm UNLESS you are accelerating or climbing. Now on the other hand, we don't have the losses associated with sending mechanical power through a complex gearbox, but I think the inefficiencies caused by running the engine at so high an RPM outweigh this. I measured around 22.7 mpg on a recent trip during which I drove at high speed for a lot of the way.

Conclusion: this car that is hopefully designed with the environment in mind is not optimised for high speed driving?

 

[Trex]

Well one of the things that was mentioned is that at > 78 mph, the ICE runs continuously.

So that should not affect you too much as from memory when I drove around California on 2 different trips over there the highest speed limit I saw was 70 mph which is approx 110 kph which is the same as around here.

But I suppose that could have changed since I was there.

So lets say you are travelling around California on the highway at the legal speeds I can remember over there I think your petrol motor should be running approx at 1,950 RPM on average over time ie approx 2950 RPM that I see at 110 kph X the approx 66% of the time the petrol motor runs that I see at that speed gives 1,947 RPM. That's a virtual electric overdrive right there IMO.

Disclaimer: that is what I see at those speeds and the loads and the drive battery SOC I travel with on my PHEV. It may vary with yours.

 

[STS134]

[Conclusion: this car that is hopefully designed with the environment in mind is not optimised for high speed driving?

Well, I think even with a basic 3 speed tranny between the clutch and the wheels, it would do a lot better. At least it could keep the engine at lower revs for cruising and higher revs for climbing.

Well one of the things that was mentioned is that at > 78 mph, the ICE runs continuously.

So that should not affect you too much as from memory when I drove around California on 2 different trips over there the highest speed limit I saw was 70 mph which is approx 110 kph which is the same as around here.

But I suppose that could have changed since I was there.

So lets say you are travelling around California on the highway at the legal speeds I can remember over there I think your petrol motor should be running approx at 1,950 RPM on average over time ie approx 2950 RPM that I see at 110 kph X the approx 66% of the time the petrol motor runs that I see at that speed gives 1,947 RPM. That's a virtual electric overdrive right there IMO.

Disclaimer: that is what I see at those speeds and the loads and the drive battery SOC I travel with on my PHEV. It may vary with yours.

Well...you're assuming everyone always obeys the speed limit. I'm not sure where you drive that this is actually the case because I've never seen anywhere where everyone obeys the limits. If you go out on I-5 and do the speed limit, people are going to flip you the bird. Most traffic goes over 80 mph and a significant number of people go over 90 mph. And the PHEV really overrevs the engine for cruising at those speeds. Heck, it's not just road trips, I go over 80 mph nearly every single day on the way to and from work if there's somewhere on the freeway that there isn't a lot of traffic.