Do not be scared of using that charge button.

[Daff]

You need to get your head around the fact that Mitsubishi and Toyota etc have worked out that the extra fuel consumption to make electricity and put the bloody inefficent petrol motor in its most efficient "zone"

The poster was asking whether using Charge when the motor is running anyway in parallel mode is free energy. Clearly not, it's adding a significant load to the engine. How many kW does the onboard generator run at? And the thing about running in the most efficient zone is not true in parallel mode. The engine revs are determined strictly by the road speed because of the fixed gearing.

Steve

 

[anko]

Steve,

When the engine runs, it runs in charge mode. There are only two exceptions:

- when the engine is stated, not because of low battery or high speed, but because of heating demand
- when the engine is started because the battery is empty or heat is demanded and the petrol tank is very close to being empty

In these cases the engine produces just enough power to propel the car but no surplus power to charge the battery.

Now the sweetspot is not so much related to rpm but much more to relative load. At a higher load we can produce more kWh of energy per liter of fuel consumed. Adding charge load to the engine increases relative load and thus efficiency. This outweighs the losses associated with storing and converting electrical energy.
.

 

[Harald]

Assuming a trip is longer than the EV range and some use of the ICE will be needed:
(some slow inner city traffic, some streets above 65 km/h)
What will be the best strategy for efficient ICE usage?

A quick rule of thumb for me is:
a)
drive all distances below 65 km/h in EV mode for avoiding serial hybrid mode
b)
when speed is sufficient for direct usage of the ICE (above 65 km/h), use "Charge" mode as much as needed for reaching next loading point with a battery that is almost empty.

Working with this rule, serial mode only starts when power demand is high for acceleration etc...

Furthermore, I use B0 mode or N position of the gears whenever it makes sense.
Keeping momentum (speed) is more efficient than accelerating and braking, even when hybrid cars can recover partially the braking energy.

Best regards, Harald

 

[Daff]

When the engine runs, it runs in charge mode.

AIUI: It runs in charge-depleting mode until it reaches the "zero bars" SOC, or until the user presses Save. When one of those happens, it enters charge-maintaining mode which generates enough power to replace (average, over a shortish time) what is being used, and thus keep the charge level stable. Only when you press Charge does it aim to increase the battery SOC over time, and clearly this increases the load on the engine (either the generator duty cycle increases, or perhaps it draws a higher current, or both).

Hopefully we are not going to dispute that increasing the battery SOC uses more fuel than maintaining it, because that is O-level physics.

The question is then, is there a driving strategy that makes that extra fuel spent charging pay back with a dividend when we use the electricity up later? I think the answer is maybe, under some circumstances. But you have several losses to recoup first (generation, charging and discharging the battery are all somewhat inefficient).

IMO better and more realistic reasons to use Charge are ones not related to saving fuel, e.g. "charge on the motorway so that I can drive without tailpipe emissions when I get to town" or "use charge on the flatlands so that I have good SOC when I reach the mountains".

-- Steve

 

[anko]

Before I respond: what is AIUI?

 

[Daff]

As I Understand It

 

[anko]

Haha. It just hit me, and I had already started preparing my response. Here it comes:

Battery maintenance mode is not maintaining battery at a rock steady SOC. It is letting the SOC oscillate between a set SOC and a percent or two above that set SOC. When the low water mark is reached, the engine is started. The car is propelled and over time the SOC is raised by 1.5%. When the high water mark is reached, the engine is turned off and the battery is discharged again. The low water mark is controlled by the car (normal mode) or by you (Save mode). This picture, posted by Trex several times, says it all:

In each of the up-going slopes (yellow, blue or green), the engine runs in the exact same state. When switching to Charge during an up-going slope in Normal or Save mode (green or blue), there is no impact on instantaneous fuel consumption whatsoever. I know this from my monitoring tools.

Note: battery maintenance mode only 'attempts' to keep SOC within a percent or two of the set level. Driving demands (towing, climbing, ...) may cause SOC to drop below the low water mark. This is shown in the bottom right corner of the graph, where the blue trace falls away. Can also happen in Save mode or even in Charge mode (as they are all the same).

 

[anko]

Hopefully we are not going to dispute that increasing the battery SOC uses more fuel than maintaining it, because that is O-level physics.

Of course not! ;-)

The question is then, is there a driving strategy that makes that extra fuel spent charging pay back with a dividend when we use the electricity up later? I think the answer is maybe, under some circumstances. But you have several losses to recoup first (generation, charging and discharging the battery are all somewhat inefficient).

I am pretty sure there is, otherwise Mitsubishi would not have bothered implementing the hysteresis cycle shown in above picture. For starters: when the onff ratio for the engine is 2:1 (not uncommon at moderate speeds), the ice will do one third less revolutions for the same distance covered. So, one third less internal resistance to overcome.

IMO better and more realistic reasons to use Charge are ones not related to saving fuel, e.g. "charge on the motorway so that I can drive without tailpipe emissions when I get to town" or "use charge on the flatlands so that I have good SOC when I reach the mountains".

Of course! But keep in mind: when the engine propels the car on the motorway, it will be done in parallel mode: most power is conveyed to the wheels mechanical (with very little conversion losses). When the engine propels the car at lower speeds (< 40 MPH) most power is conveyed to the wheels not directly but via generator and E-motors. So IMHO Charge mode allows you to use the engine in it's most efficient way and can help you increase fuel economy.

 

[greendwarf]

Once you are using the ICE for heating, it might be sensible to be in Charge mode so that that heat from the extra load is useful rather than having the ICE running for no other purpose.

Yes running the petrol motor for heating alone would be something I would try to avoid if I lived over there. Unless it was bloody cold and then I would probably just say "stuff it". :lol:

.
But the reverse is also true, that if using Charge (and its winter) you might as well have the heating on to make use of the otherwise wasted heat from the ICE. BTW snowing here in the Sarf Lundun Alps.

 

[greendwarf]

When the engine runs, it runs in charge mode.

AIUI: It runs in charge-depleting mode until it reaches the "zero bars" SOC, or until the user presses Save.
-- Steve

Incorrect, when using the ICE for heating, the car also uses power to drive the car (presumably to increase the load and efficiency). Under these circumstances SOC is maintained whilst the ICE is running and only drops when the ICE stops intermittently when the ICE temp peaks for heating.

 

[Daff]

When switching to Charge during an up-going slope in Normal or Save mode (green or blue), there is no impact on instantaneous fuel consumption whatsoever. I know this from my monitoring tools.

I can believe that. But in charge mode it will keep on for longer until SOC reaches 80 percent or whatever percentage it tops out at, and then it will go into the maintenance cycle. So the instantaneous drain is the same but the duty cycle changes, it must do or the car would gain SOC up to the max in save mode, which clearly it does not.

The poster who I first replied to wanted to know whether you might as well select charge when the engine is running anyway. The answer is complicated and is definitely not a clear yes, and in the general case I think the answer is no.

Steve

 

[generaltso]

But if you’re traveling at 75mph, the ice has to remain running the entire time since you’re over the max speed of EV only mode, correct? If the engine is running all the time at this speed to propel the car, is it also charging the battery? Does the charge button at this speed change that?

 

[Daff]

Yes, it does change it. If you press Charge then the battery gauge will increase over time. If you don't, it won't.
That is an additional load on the engine which must be satisfied by burning additional fuel.

Steve

 

[ChrisMiller]

I happened to be passing a brand new (he told me it was two weeks old) PHEV yesterday, while the owner was 'loading' his dog into the back. I asked how he liked it and he said it was great, but he found all the manuals and buttons a little daunting. My response was to point him to this forum, if he wanted to learn more, but also to say that it's a bit like a new PC or smartphone. Some people like to try to understand every nuance of operation and download lots of apps to change the look and feel to suit their needs; while others simply use it and never change anything. There's nothing inherently 'wrong' with either approach, but if he preferred to simply leave it in D and drive it using the brake and accelerator, he wouldn't lose out on fuel consumption by more than a few percent.

 

[anko]

when using the ICE for heating, the car also uses power to drive the car (presumably to increase the load and efficiency). Under these circumstances SOC is maintained

In this case, "maintained" is really "maintained at a set level", rather than "maintained between at a set level and a percent or 2 above that set level". Maybe better to say "left alone" as "maintained" suggests active involvement.

I have always wondered why it would not go into proper Save mode and increase the efficiency even further. Come to think of it, it might be counter productive. For heating it is better when the engine runs for a longer period of time and is properly heated up, through and through. Not just the coolant as that wil cool off rather quickly.

 

[anko]

But if you’re traveling at 75mph, the ice has to remain running the entire time since you’re over the max speed of EV only mode, correct? If the engine is running all the time at this speed to propel the car, is it also charging the battery? Does the charge button at this speed change that?

Earlier I worote:

There are only two exceptions:

- when the engine is stated, not because of low battery or high speed, but because of heating demand
- when the engine is started because the battery is empty or heat is demanded and the petrol tank is very close to being empty

Maybe I should have written:

There are only three exceptions:

- when the engine is stated, not because of low battery, but because of heating demand
- when the engine is stated, not because of low battery, but because of speeds over the maximum EV speed (approx 125 km/h)
- when the engine is started because the battery is empty and the petrol tank is very close to being empty

 

[anko]

Yes, it does change it. If you press Charge then the battery gauge will increase over time. If you don't, it won't.

And that makes sense, as (under the current driving conditions) you would never be able to use the additional charge.

To be honest, I don't have that much experience with what happens at above-EV speeds, because personally I think it is rather silly to drive this car at such speeds

 

[anko]

The poster who I first replied to wanted to know whether you might as well select charge when the engine is running anyway. The answer is complicated and is definitely not a clear yes, and in the general case I think the answer is no.

Indeed it depends on circumstances, most important what the rest of your trip will look like, up to your next grid charge. "In general yes" is as easily defended as "in general no", so maybe it is better not to go there ;-)

 

[Daff]

Yep. What would be nice in a future version would be a predictive hybrid strategy linked to satnav data about route, road type, traffic and elevation changes. I know some other makes have this feature and it would certainly make it easier to optimize, especially for the person Chris gave his excellent advice to.

Steve

 

[plhev]

Thanks Trex for the posting.

Just a quick intro, I'm an ex-prius car user for 8 years who lives in a tower block with no access to power charger and have recently converted to Outlander PHEV.

For the people haven't driven a prius before, it's simply start and go! The car fully charges itself when the battery is depleted and it switches you back to the battery mode automatically. The cycle repeats itself again with no further action is required. The downside of my old prius is the battery doesn't work over 30mph, whereas, Phev can run on EV mode double the speed so, that is a big advantage.

Whereas the phev is different contrast, you have to make additional efforts and manual adjustment to get into EV mode compare to my old routine, drive and go.

As such, IMHO in long driving condition (i.e over 100 miles) activating charge on the motorway when the battery is flat and far away from charging points make sense.

Remember, Mitsubishi rolled out the phev when the electric charging points are scarce so, do not be scared of using that charge button. It's there for a reason! :lol:

Hello fellow ex prius driver.

There are a few of us here if my memory serves me correctly.

The Prius was a part of my life that I do not regret as a start into learning the world of hybrids but I defiantly prefer the PHEV better for a number of reasons like driving position. size and even better fuel consumption when considering the Plug in part. It was a great car even though a lot of people put crap on it. :lol:

I still own a Toyota Camry Hybrid which my oldest son drives in the family business. Looks more "normal" :lol: than the prius but still great on fuel etc.

But I digress.

Welcome to the forum.

Regards Trex.

Thanks again Trex.

Agreed. Thus, we choose Phev rather than other cars.

No regrets, we love the luxury that comes with it