Advise on how to get best MPG?

[anko]

I believe the ICE turning on and off while in save mode (or depleted battery) while cruising on motorways is simply because the ICE will use surplus torque (i.e. it will put load onto the generator when it has surplus energy) so the drive battery is often being charged even in save mode. When the charge level exceeds the charge level that save mode was selected at, it switches to EV mode until the charge level drops back down again.

Yes. As Jaap says, it is no so much surplus torque (as something that would go to waste when not used) but more a torque reserve. The engine can produce more torque (or power) than what is needed for driving. And it will do so, be cause generating this additional torque / power cost less than generating the same amount of torque / power when the engine was not already running (during the subsequent EV drive period). And yes, there is additional cost (fuel consumption) involved in activating the torque / power reserve, but this cost and a bit more is recovered in the subsequent period of EV drive.

Mitsubishi themselves actually state that using charge mode, then EV mode, rather than just running in save mode will use about 20% more fuel. Presumably, this is due to the inefficiency of charging and discharging the battery. As opposed to the "surplus" but lesser amounts of energy used to recharge the battery in save mode.

I've read this in another post. Came from the Aussies, I think. IMHO, there could be two reasons for this statement:

a) When the battery stays at a higher SOC, less of the torque / power reserve can be used to charge the battery, because the battery will not accept as high as a charge current as it would at a lower SOC. If this is the reason, running in charge mode would not be so bad when you do so at a (very) low SOC, but it would be bad when using it to get to a higher SOC. Theoretically, if you could engage Charge mode at 80% SOC, or set the Save level at 80%, you would no longer be driving a hybrid vehicle, as the charge current would drop to 0. And then, 20% less efficiency makes sense, all of a sudden.

Engaging Save mode at higher SOC would be equally bad. And this is why I suggested earlier that engaging Save mode to save (larger part of the) SOC for the trip home could be a poor decision.

b) The statement is a bit misconstrued, as they compare the instantaneous fuel consumption associated with driving with the instantaneous fuel consumption associated with driving + charging. I can imagine how the fuel consumption increases by 20% when the torque / power reserve is actually activated to charge the battery. This 20% and a bit more would than have to be recovered in the next EV drive period. But if this is the reason, it has nothing to do with Charge mode, but with charging while driving in general. And this is something you can't really prevent other than by making short trips only.

The most authoritive comment on these forums that is consistent with my observations was from anko who said:

Appreciate it

 

[anko]

The motormanagement keeps the engine running as optimal as possible related to the power demand.

If I am not mistaken ....

Unfortunately, this is strongly limited by the maximum charge current that is /can be accepted by the battery. Again, at lower SOC the motor management has more "room to play" as the charge current can be higher. But even then, the charge current will still be limited so much, that the motor management can not get anywhere near the sweet spot of the engine. Think in terms of 110 Nm produced where the sweetspot starts at 140 Nm or something like that.

Now, when towing a trailer or during climbing, the combined load for driving and charging should get you much closer to the sweet spot, but unfortunately, the motor management seems to reduce charing when more power is needed for driving. As in: it steers towards a predefined combined output, which is below optimal, as it is based on solo driving..... .

... will result in the engine being adapted to deliver more, resulting in a higher consumption.

but also

... will result in the engine being adapted to deliver more, resulting in a higher efficiency.

 

[maby]

Don't forget that my original point in this thread was a strategy for making the car more comfortable to operate, not maximising fuel efficiency. I'm not particularly interested in squeezing the last few MPG out of it - I want to keep the engine revs down and have good acceleration in reserve. Others on this forum have reported the engine revs running up high climbing hills or accelerating hard and at the time, I remarked that I had not observed that - now, having done some experiments, I've come to the conclusion that I probably don't see it because I avoid the battery getting too depleted. That suits my driving style and preference - may not suit yours.

 

[anko]

I'm not particularly interested in squeezing the last few MPG out of it

That has become clear. I think I was and still am too much distracted by the title of this thread :lol:

 

[maby]

Looking back over this discussion, it also occurs to me that there is probably an element of psychology in the way Mitsubishi has set up the control algorithms. The Outlander is not designed to appeal to the user base that would otherwise purchase a performance sports car - it may well be the case that the petrol engine is perfectly happy running at over 4000rpm and could be more efficient there, but I don't like hearing the engine in my car running like that. You hear sports car drivers happily pushing their engines up to five or six thousand revs, but it sets my teeth on edge - I prefer my engine ticking over at a couple of thousand revs - as, I suspect, do the majority of 4x4 owners!

 

[steve2001]

Others on this forum have reported the engine revs running up high climbing hills or accelerating hard and at the time, I remarked that I had not observed that - now, having done some experiments, I've come to the conclusion that I probably don't see it because I avoid the battery getting too depleted. That suits my driving style and preference - may not suit yours.

I also do not like high revving and my previous diesel car rarely went above 2000rpm. On a morning school run in the PHEV the heating is set to 21/22C. Because it is a Gx3, the ICE kicks in for most of the journey. There is a moderate hill less than 1 mile into the journey and I always hear high revs until reaching the top. I could stop ICE running by turning off the heating but prefer a warm car, especially with kids onboard. I can get up that same hill easily without ICE.

So - If ICE is kicking in only to heat the car, and it doesn't need to run to support the electric motors to climb the hill, why does it rev so highly on the hill? It is not from having a depleted battery - this is full from overnight charging. ICE also kicks in if I accelarate more than 'half way' e.g. into the white 'power' part of the display on flat roads.

It seems to me that once ICE is running - it will rev higher under even moderate load/acceleration regardless of battery levels.

 

[anko]

Steve,

Is this at above 65 km/h? In that case, may I suggest trying to select Charge mode? I have noticed that the car will not engage Parallel mode if the engine is running for heating purpose. Unless you select Charge mode.

 

[steve2001]

Steve,

Is this at above 65 km/h? In that case, may I suggest trying to select Charge mode? I have noticed that the car will not engage Parallel mode if the engine is running for heating purpose. Unless you select Charge mode.

No it is quite the opposite Anko. I am pulling out from a junction straight onto the hill so this is from a standing start. It is a fast road so i have to give some reasonable accelaration to avoid slowing down the Beamer drivers bearing down on me from behind - flash lights/horns But I am not flooring the pedal.

I can try selecting Charge mode but the battery is full?

Thinking about it the PHEV must be working hard to accelarate from zero to about 30/40mph (50-60km/h?) in about 500 metres uphill. The engine is cold and the car is heavy with passengers. But I can still do it easily without ICE if I turn off the heating! In fact the accelaration better/faster from the instant torque when electric only. That is the only frustrating part for me...

 

[anko]

I can try selecting Charge mode but the battery is full?

Hmmmm, probably not

Thinking about it the PHEV must be working hard to accelarate from zero to about 30/40mph (50-60km/h?) in about 500 metres uphill. The engine is cold and the car is heavy with passengers. But I can still do it easily without ICE if I turn off the heating! In fact the accelaration better/faster from the instant torque when electric only. That is the only frustrating part for me...

Whether the engine is running or not, you are using the electric motors. IMHO, there is no reason why you would have less torque. Can your observation be a misconception, possibly inspired by the fact that the sound does not match the acceleration?

 

[steve2001]

I can try selecting Charge mode but the battery is full?

Hmmmm, probably not

Thinking about it the PHEV must be working hard to accelarate from zero to about 30/40mph (50-60km/h?) in about 500 metres uphill. The engine is cold and the car is heavy with passengers. But I can still do it easily without ICE if I turn off the heating! In fact the accelaration better/faster from the instant torque when electric only. That is the only frustrating part for me...

Whether the engine is running or not, you are using the electric motors. IMHO, there is no reason why you would have less torque. Can your observation be a misconception, possibly inspired by the fact that the sound does not match the acceleration?

Yes you a re probably right I expect it is my misconception regarding accelaration. But I still believe ICE does not need to rev so highly in this scenario if there is enough torque and power available already from the electric motors.

 

[anko]

But I still believe ICE does not need to rev so highly in this scenario if there is enough torque and power available already from the electric motors.

The power does not come from the motors, but either the battery or the engine. The motors only convert electrical power into mechanical power. So, the real question should be: why does the power have to come from the engine, as there seems to be plenty of power available in the battery.

I think the idea is that, given the fact that the engine is already running, getting the power from the engine is probably more energy efficient than getting the power from the battery and recharging the battery later. Of course the battery does not need to be recharged, as this is just a school run. But the car doesn't know this

About a year ago, I asked Mitsubishi if the cars brain would take into account a destination set in MMCS. The answer was clearly: NO.

 

[maby]

...

About a year ago, I asked Mitsubishi if the cars brain would take into account a destination set in MMCS. The answer was clearly: NO.

That would make sense and I'm sure it will come in the future - though not necessarily as an update to existing cars.