Fuel economy at highway speed phev vs ice model

Good day all,
I'm new here and posting my first post. I have searched all through the tech section and could not find the answer so here it goes. I am getting a 2023 Outlander PHEV in the first week of January. I can tell the vast majority of users here really like their Outlanders.

When comparing the highway fuel economy between the ICE version of the Outlander and the PHEV version, I was surprised to see the ICE version was more efficient. I was trained as an Engineer in 1990 but became a pilot and have not used my engineering degree since graduation. So I understand some physics but am by no means current.
It's my understanding that air resistance and therefore body style is the main determining factor for how much energy is needed to keep the can going at highway speed. Both versions of those Outlanders have the same body style and chassis. Both have the same engine except the ICE version has a slightly higher compression ratio and operates on the conventional Otto cycle. The PHEV operates on the more efficient Atkinson cycle. Sure the PHEV is heavier but with the Atkinson cycle and the direct drive to the front wheels in parallel mode without a transmission should be more efficient. The only thing I can think of is the efficiency losses as you generate electricity for the batteries and the efficiency losses as you use the energy put back in the batteries as the engine cycles on and off. 2023 Outlander ICE gets 7.9 litres per 100km, PHEV gets 8.7.
Interesting the Toyota RAV 4 PHEV gets better highway fuel economy than the ICE version and regular Hybrid is better than both. Rav 4 PHEV 6.4 l/100km, Rav 4 Hybrid 6.3, Rav 4 ICE 6.9. All three Rav4s have the same engine and they all have transmissions. How can the Rav4s with batteries and motors and extra weight get better fuel economy than the ICE but the Outlander can't?
So is the testing cycle forcing the Outlander in series mode sometimes? To my knowledge, Canada uses the same cycle as the USA EPA uses.

For real life, I really only care about steady 105 kmh or 115 kmh fuel economy. The city numbers don't matter to me because I will be using the battery and electric motors then. Does Toyota have it right with their mechanical set up or does Mitsubishi have it right? Again, I would think the Mitsubishi set up should do better. I initially had put my name on a list for a Rav 4 as its ev range is 68 km. It's 58 km round trip for us to go to town for errands. Before 2023, the Outlander didn't have the ev range we needed. After being on the Rav4 list for 15 months and them being told I would have to wait at least 6 more months, I put myself on the wait list for the 2023 Outlander with the 20 kwh battery and 61km ev range. It's a 70 to 80 kmh road to town so I expect to get much more range than the 61 advertised.

We mostly stay local but we also do some highway trips so I am still interested in highway fuel economy. The Rav 4 gets better mileage but I don't know how long I would have to wait. I'm currently driving an ICE car that gets 7.1 highway.

Anyone have real world highway fuel numbers on the 2023 Outlander PHEV (it has a larger body and chassis)?

Andrew

Just a random thought, make sure that you're not comparing a Diesel Outlander with a Petrol Outlander.

Otherwise, my guess would be under-inflation of the tyres on the PHEV.

According to the company that sold me my tyres, the manufacturers recommendation of 38 psi was too low, and they were able to demonstrate that my previous tyres had 'under-inflation' wear pattern.

They recommended 41 psi.

If the two Outlanders had identical tyre pressures for the measurement runs, that would explain the poor results for the heavier vehicle.

I note that you're considering a difference of less than one litre of fuel per 100 kilometres...

Grungy said:

It's my understanding that air resistance and therefore body style is the main determining factor for how much energy is needed to keep the can going at highway speed.
Andrew

Click to expand...

What you are missing is the mass. The PHEV is heavier because of the batteries.

Good point if the tires are under inflated. Interesting that Mitsubishi could not figure out what the proper tire pressure should be.

As far as the PHEV being heavier, that should not effect highway fuel economy that much. The Toyota Rav4 PHEV is heavier than the ICE Rav4 but it gets better fuel economy. So I don't think the weight is the reason why.

Grungy

Weight (mass) is pertinent when accelerating or hill climbing, of course, and it may affect rolling resistance. The last factor is largely dealt with by higher tyre pressures. It's an education to one such as myself whose driving life has hitherto been exclusively ICE just how much weather and speed can affect economy. I already knew that wet roads cause higher consumption, and headwinds likewise, but some diesel cars (I've had four) are at their most economical at the upper end of legality - 60mph or thereabouts. My diesel Jaguar X-Type is barely above idle in 6th gear at 60mph. An EV is consuming energy in handfuls at higher speeds though.

EVs are very seriously affected by cold weather and 'hotel loading' - i.e. heater/aircon, lights and wipers. The heater being head and shoulders worse than any other. Driving style is, I find, gentler in an auto and more so still in an EV than it is in a manual. I'm constantly striving to reach the speed of the next upward gear change in a manual.

Grungy said:

As far as the PHEV being heavier, that should not effect highway fuel economy that much. The Toyota Rav4 PHEV is heavier than the ICE Rav4 but it gets better fuel economy. So I don't think the weight is the reason why.
Grungy

Click to expand...

It's true that the Mitsubishi Outlander PHEV does have a lower fuel economy rating than some other PHEV SUVs, such as the Toyota Rav4 Prime. However, it's important to keep in mind that the Outlander PHEV has significantly better all-wheel drive (AWD) capabilities.

See more here: https://www.myoutlanderphev.com/forum/viewtopic.php?p=60374#p60374

Based on my limited experience with the 2023 PHEV, I wonder if it has to do with the design of the system where the ICE charges the battery in non-demanding situations, rather than directly propelling a transmission or axle? There is no setting that I know of to prevent the ICE from charging the battery. Even when the battery is 100% and Save mode is selected, I think the battery is drained to the Save level (as best as it can, it will still use some battery even at 100%) and then charged back to that level by the ICE. Whereas in the RAV4 PRIME, I believe HV mode is only hybrd and the ICE does not charge the battery. I believe there is a Charge mode to do that on the RAV4, but it is not default like it is on the Outlander.

So I wonder if the difference in approach to EV charging vs hybrid driving contributes to the fuel economy differences between the PHEV and hybrid model from each manufacturer?

Hasenphever said:

Based on my limited experience with the 2023 PHEV, I wonder if it has to do with the design of the system where the ICE charges the battery in non-demanding situations, rather than directly propelling a transmission or axle? There is no setting that I know of to prevent the ICE from charging the battery. Even when the battery is 100% and Save mode is selected, I think the battery is drained to the Save level (as best as it can, it will still use some battery even at 100%) and then charged back to that level by the ICE. Whereas in the RAV4 PRIME, I believe HV mode is only hybrd and the ICE does not charge the battery. I believe there is a Charge mode to do that on the RAV4, but it is not default like it is on the Outlander.

So I wonder if the difference in approach to EV charging vs hybrid driving contributes to the fuel economy differences between the PHEV and hybrid model from each manufacturer?

Click to expand...

First of all there is no point to use Save or Charge before your battery drops. Battery won't be charged by the ICE over 80% anyway.
There isn't a setting to prevent ICE charging the battery cause there is no transmission and the ICE should be used in a most efficient way possible at required for the speed rpm's? Outlander PHEV's most efficient way is to use the ICE is for propelling the vehicle and using excess available power to charge the battery where in RAV4 Prime the transmission can use the ICE on highway in more efficient rpm's without charging the battery.

kpetrov said:

First of all there is no point to use Save or Charge before your battery drops. Battery won't be charged by the ICE over 80% anyway.
There isn't a setting to prevent ICE charging the battery cause there is no transmission and the ICE should be used in a most efficient way possible at required for the speed rpm's? Outlander PHEV's most efficient way is to use the ICE is for propelling the vehicle and using excess available power to charge the battery where in RAV4 Prime the transmission can use the ICE on highway in more efficient rpm's without charging the battery.

Click to expand...

So, the crux of the difference between an Outlander PHEV vs Outlander gas and the Rav4 PHEV vs Rav4 gas is really the lack of a transmission in the Outlander PHEV?

I believe so, but the lack of transition increases the reliability and reduces the price.
I got it for that reason and Prime unavailability. All my daily trips are in battery range, occasional long ones with fuel economy equal to conventional vehicle.

The Toyota Rav4 Prime similar to the Toyota Rav4 Hybrid has an eCVT that drives the front wheels and a weak electric motor driving the back wheels when needed. The AWD capabilities of the Hybrid and Prime Rav4 are limited compared to the Mitsubishi Outlander PHEV. The Rav4 Prime's torque on the front wheels is so much, it will spin them always if you depress the pedal more than half-way through.

An eCVT (electronically controlled continuously variable transmission) is a type of transmission that uses a planetary gear set to connect the engine and wheels. The planetary gear set allows for a continuous range of gear ratios, rather than fixed gears found in traditional transmissions. The transmission uses electrically-controlled actuators to adjust the gear ratio smoothly, providing an infinite number of gear ratios. This allows for smooth and efficient operation, improving fuel economy and performance. It is commonly used in hybrid and electric vehicles. It's not cheap to build and on top of that when the battery is depleted the system constantly turns on and off the ICE (especially in the normal hybrid), which is not very good for the long-term usage of the batteries.

Now, compare this to the Mitsubishi Outlander PHEV single-speed transmission, which will utilize the ICE only at high-speeds when the engine is efficient, and at all other times drive both the front and back wheels with electric motors, offering a much better AWD capability.

So it really depends on what you are looking for exactly. If you don't care about mostly front-wheel biased systems and good AWD, and OK to wait between 12-24 months for a Toyota, it's worth it. Otherwise, just take the Outlander PHEV.

Most people that buy a hybrid probably don't care about 4WD capability, but do care about fuel efficiency.

littlescrote said:

Most people that buy a hybrid probably don't care about 4WD capability, but do care about fuel efficiency.

Click to expand...

Now that's interesting.

For me the reasons for buying the PHEV went in this order:

1. Plug in hybrid (because 99% of my driving would be on electric)
2. Cabin height (because I'm tall)
3. Floor/seat height (because it is difficult for me to get down to the car seat in low cars due to a back injury)
4. Storage space (and ability to carry tall loads)
5. 4WD and ground clearance (re using and launching my kayak)
6. Didn't even consider litres per hundred kilometers

Note that my previous car (Barina GSi/Opel Corsa) had better fuel economy but that becomes irrelevant when most of your driving is on electric.

And again, you're talking about a difference of one litre per one hundred kilometres. That's a trivial difference in fuel economy.

nrayanov said:

The Toyota Rav4 Prime similar to the Toyota Rav4 Hybrid has an eCVT that drives the front wheels and a weak electric motor driving the back wheels when needed. The AWD capabilities of the Hybrid and Prime Rav4 are limited compared to the Mitsubishi Outlander PHEV. The Rav4 Prime's torque on the front wheels is so much, it will spin them always if you depress the pedal more than half-way through.

An eCVT (electronically controlled continuously variable transmission) is a type of transmission that uses a planetary gear set to connect the engine and wheels. The planetary gear set allows for a continuous range of gear ratios, rather than fixed gears found in traditional transmissions. The transmission uses electrically-controlled actuators to adjust the gear ratio smoothly, providing an infinite number of gear ratios. This allows for smooth and efficient operation, improving fuel economy and performance. It is commonly used in hybrid and electric vehicles. It's not cheap to build and on top of that when the battery is depleted the system constantly turns on and off the ICE (especially in the normal hybrid), which is not very good for the long-term usage of the batteries.

Now, compare this to the Mitsubishi Outlander PHEV single-speed transmission, which will utilize the ICE only at high-speeds when the engine is efficient, and at all other times drive both the front and back wheels with electric motors, offering a much better AWD capability.

So it really depends on what you are looking for exactly. If you don't care about mostly front-wheel biased systems and good AWD, and OK to wait between 12-24 months for a Toyota, it's worth it. Otherwise, just take the Outlander PHEV.

Click to expand...

Great explanation on the difference between the Outlander and RAV4 transmissions.

Knowing that, why might the Outlander PHEV fuel economy be rated higher than the ICE version, while the RAV4 Prime is rated lower than its ICE version?

AndyInOz said:

littlescrote said:

Most people that buy a hybrid probably don't care about 4WD capability, but do care about fuel efficiency.

Click to expand...

Now that's interesting.

For me the reasons for buying the PHEV went in this order:

1. Plug in hybrid (because 99% of my driving would be on electric)
2. Cabin height (because I'm tall)
3. Floor/seat height (because it is difficult for me to get down to the car seat in low cars due to a back injury)
4. Storage space (and ability to carry tall loads)
5. 4WD and ground clearance (re using and launching my kayak)
6. Didn't even consider litres per hundred kilometers

Note that my previous car (Barina GSi/Opel Corsa) had better fuel economy but that becomes irrelevant when most of your driving is on electric.

And again, you're talking about a difference of one litre per one hundred kilometres. That's a trivial difference in fuel economy.

Click to expand...

Good summary, and is similar to my reasons, but I think that actually your number 1 priority kinda overlaps with number 6. By choosing to run largely in electric, your average fuel consumption will be low, even if the fuel consumption when actually consuming fuel may be high. I do most of my journeys on electric only so when I do the longer journeys that have relatively poor fuel consumption compared to other choices that I could have made, it's worth the sacrifice.

Hasenphever said:

Great explanation on the difference between the Outlander and RAV4 transmissions.

Knowing that, why might the Outlander PHEV fuel economy be rated higher than the ICE version, while the RAV4 Prime is rated lower than its ICE version?

Click to expand...

You are welcome.

If you quote the exact numbers you are talking about I could provide a little bit more insight.

I have driven the (US model, I’m in Seattle) 2023 PHEV only once, but have owned a 2018 PHEV since new.

The 2018 is EPA-rated at 26 mpg and this is exactly what you will get on the freeway at 60 mph if you just keep it in the default D gear and don’t use Charge mode and start out with a completely depleted lithium battery pack. That is, 26 mpg is what the gasoline engine on its own, in the MY2018 PHEV, will deliver.

I have no idea how the EPA testing rules affect other hybrids’ official mpg ratings such as the Toyota hybrids.

I do know that in real world everyday use with my PHEV in service as my fulltime Uber vehicle, taking prudent advantage of the range extension provided by the lithium battery pack, I routinely get 30 to 35 mpg on the freeway (Interstates 5, 90, and 405 at 60-70 mph). This is with the AC and heating always on (climate control set at 73-76°F depending on outside air temperature), usually with the adaptive cruise control on, and with 4WD Lock always on except when going uphill (the torque of the rear motor acts as additional damping on the rear suspension, thus giving my passengers a smoother ride) (but for some unknown reason when going uphill with 4WD Lock on the Charge mode does not work, so I shut 4WD Lock off until I crest the hill. The rear motor continues to be used anyway.). Oh, and also, that’s with Michelin Primacy Tour all-season 225/60-R18 tires which have more rolling resistance than the factory 225/55-R18 Toyo A24’s. I have found that the taller the sidewall the better the ride and the MUCH quieter the cabin. My next tires will be 235/65-R18.

Overall mileage is around 28 mpg but this poor of mileage is only because I idle a lot and stop and start a lot. Take the car out of Charge or Save mode when stopped, to cause the gasoline engine to shut off. I often forget to do this. When I consistently remember to use null mode at standstill I get 30-31 mpg combined city+freeway, calculated at the gas pump at the end of the day. Oh, and, I almost never use external charging.

There is another current thread, having to do with a burning rubber smell, in which I describe my complete driving regimen. I don’t know how applicable it would be to the 2023 PHEV because the 2023 no longer gives you a single button to drop in or out of 4WD Lock mode, instead it has a road surface selector knob which I have not had time yet to experiment with. But I would bet that I could make the 2023 PHEV give the same 20-25% more mpg as a daily average than its official EPA-rated 26 mpg (combined city+highway), just as I do with my 2018.

2018gt said:

with 4WD Lock always on except when going uphill

Click to expand...

Any reason why you do NOT use the 4WD Lock when going uphill?

The maximum traction on the back tyres will be most efficient exactly in this scenario.
What I'm trying to say is that, you should ALWAYS use the 4WD Lock.

According to numerous owners of the 3rd GEN Outlander PHEV the most fuel efficient way to use the car is ECO mode + 4WD Lock.

Now I know you are not into pulling out the best efficiency because you are an UBER, but I hope the information I shared will be helpful to you.

I guess it’s a quirk of the charging management system. Going uphill with 4WD Lock on, in Charge mode, the battery does not charge. But if I take 4WD Lock off, the rear motor continues to be used, but now the battery charges.

I don’t use ECO mode unless no other traffic and wide open road, simply because I insist on having the maximum acceleration available at all times, purely for safety reasons.

nrayanov said:

If you quote the exact numbers you are talking about I could provide a little bit more insight.

Click to expand...

See the first post in this thread.