Bugs and odd decisions in the Outlander PHEV

[ian4x4]

I think that the diesel v petrol or normal v turbocharged argument is ignoring the fact that the PHEV engine does not follow the convention tuning criteria in so much that the torque rises gradually to peak at the same 4500 rpm as the max power.

I am not sure why this is, but it must surely be to get the best efficiency out of the petrol generator.

Ref page 24 of the PHEV Tech Highlights.

 

[Claymore]

I think I may have contracted Dutch Elm70 disease :shock:

JimB

 

[elm70]

I think I may have contracted Dutch Elm70 disease :shock:

JimB

Sorry ... it sounds really bad

I think that the diesel v petrol or normal v turbocharged argument is ignoring the fact that the PHEV engine does not follow the convention tuning criteria in so much that the torque rises gradually to peak at the same 4500 rpm as the max power.

I am not sure why this is, but it must surely be to get the best efficiency out of the petrol generator.

Ref page 24 of the PHEV Tech Highlights.

My guess ... of Usage of Petrol vs Diesel .. is due to the widest RPM range that can make it able to drive in the single gear, in "parallel" mode from ~70kmh till 170kmh .. with diesel they will have a narrow range .. keeping 170kmh max, possibly it will have been only from 100kmh

Other issue of avoiding Diesel and Turbo could have been about dimension ... fitting under the bonnet the ICE, the electric motor and generator could have been a challenge if also turbo elements were needed

Still ... I don't see the advantage of Parallel mode, if this cause high level of consumption. Better to keep only the series mode and pure EV mode .. and have the best engine that can produce between 60kw to 100kw with the highest efficiency .. and I bet the most efficient will be a turbo diesel .. which will avoid the 3 months fuel ageing issue too.

Anyhow ... interesting to see that nobody else have made a similar design ... it would have been nice to have comparisons

 

[zzcoopej]

the diesel v petrol or normal v turbocharged argument

The other step between the BMW i3 and Outlander PHEV is the BMW i8 with its 1.5l turbo ..... they didn't choose diesel either.

 

[jaapv]

I'm a bit puzzled. At lower speed the effect of alternating between EV and series hybrid will be economic with smart switching.
At higher speeds, with a constant power demand on the ICE, it is surely more efficient to cut out the conversion losses by linking the engine directly to the wheels?

 

[elm70]

the diesel v petrol or normal v turbocharged argument

The other step between the BMW i3 and Outlander PHEV is the BMW i8 with its 1.5l turbo ..... they didn't choose diesel either.

i8 is a "SportCar" with a super price
i3 is a "NomarlCar" .. with a premium price

i8 want to be "Sport" with Eco touch .. but not extreme "fuel economical"
i3 is more a pure EV, with a small ICE for reduce "range stress"

Fisker Karma ... also used a Petrol Engine .. but this is more a "hobby design" .. not a real R&D outcome from one of the few big car companies

I'm a bit puzzled. At lower speed the effect of alternating between EV and series hybrid will be economic with smart switching.
At higher speeds, with a constant power demand on the ICE, it is surely more efficient to cut out the conversion losses by linking the engine directly to the wheels?

Yes ... it is a puzzle

At high speed (but less them 160kmh) is still is possible to increase "load" by charging battery and increase the ICE efficiency
Still .. having the EV motor always "connected" ... EV motors cause a "drag", which need to be "cured" by providing Epower to them even when not used (actually I'm just coping the anko point .. I don't really get this .. I'm using brushless engine for hobby since ages .. and I never notice any special effect or special "resistance" at high rpm :?: )

Anyhow ... looking at a direct drive ... possible a dual speed gear and a turbo diesel engine would have been a better solution .. assuming all could be fitter under the bonnet

I think KIA now has a PHEV, which the EV motor is connected to the main ICE, so both use the same traditional gear box .. this is also another possible approach

PS: Personally I like "simple" design .. so no parallel system .. even if it may gain some efficiency in special condition ... so ... having the least component is the best ...so ... ICE only as generator .. and the smallest and lighter and efficient for the power needed ..

 

[jaapv]

I don't really get this .. I'm using brushless engine for hobby since ages .. and I never notice any special effect or special "resistance" at high rpm :?: )

Well, that is rather basic:

Counter EMF is simple physics:

https://lmgtfy.com/?q=counter+emf

 

[ian4x4]

My point about the Mitsubishi PHEV engine was meant to be that it is a specialised unit, modified as explained in the PHEV Technical Highlights, to suit it's job with that particular design.
Few, if any, other cars attempt the same design as the Outlander, which to me seems to be a good method of propelling a SUV.

To me, the i3 is a range extender with limited ICE power, and the i8 is an ICE powered car with extra electric assistance.

Quite a few hybrid and phev cars use the intregrated ICE/generator/motor inline with gearbox and clutches, but this is not the design Mitsubishi choose.

I think we need to look upon this topic as our efforts to improve on what Mitsubishi has started.

 

[Fecn]

Another one for the list...

The button for the heated steering wheel down at the bottom of the centre console when there are many empty slots in the row of buttons next to the steering wheel.

 

[elm70]

Well, that is rather basic:

Counter EMF is simple physics:

https://lmgtfy.com/?q=counter+emf

simple ... very simple

The effect of variable magnetic field and coils is clear.

What is not trivial is the impact when the coils have no load .. since the voltage that is created in the coils is not used so .. there should be no resistance to the rotation due to this. (The most simple "electric" brake for a motor, is just to short the 2 or 3 poles of the motor, this maximize the resistant to rotation, but when the poles are "free" so without any load, resist should be "zero" in theory.

In practice .. due to parasite capacitor effect , and non "zero" resistance inside the wire used in the coil ... we can have some "waste" .. so some rotation energy could be end up in "coil" heating ...

Still .. it should be relative small .. and still .. I'm not sure why applying power it will make "less waste"

Anyhow .. it is all .. than simple :ugeek:

 

[elm70]

To me, the i3 is a range extender with limited ICE power, and the i8 is an ICE powered car with extra electric assistance.

Don't agree much on these definitions

Anyhow .. i8 is a "sport" "extreme" car .. so it is not relevant.

Maybe also i3 is more a "concept" car then a "main stream car" still ... I think it is a valid example

Why i3 ICE power is too little for your point of view ?
I think the ICE power should be dimensioned exactly for the average power need by the car for normal usage, plus a little extra buffer (up to +25%) .. the buffer also need to be extended in case the size and limit of the battery pack of the car. So .. i3 ICE is perfectly dimension in my view

Anyhow ... it is not the size of the ICE that does matter .. what matter is if the extra complexity of parallel mode does bring any advantage .. especially if this cause to pick up a diesel vs petrol .. or a turbo vs no turbo ... and if this implies to have to implement the 3 months time for the mandatory 15L of fuel to be burned or top up in the tank.

Clearly .. parallel mode is .. technically "fascinating" .. since it is unique for a single gear concept .. but . I'm not sure it does bring real advantage at the end (speaking of end customer/driver OPEX and CAPEX)

 

[anko]

Anyhow ... it is not the size of the ICE that does matter .. what matter is if the extra complexity of parallel mode does bring any advantage .. especially if this cause to pick up a diesel vs petrol .. or a turbo vs no turbo ... and if this implies to have to implement the 3 months time for the mandatory 15L of fuel to be burned or top up in the tank.

All the time you are referring to the how nice it would be to have something like the BMW 2-speed drive. And how other hybrid cars have a complete gearbox. How are these less complex that a straightforward parallel drive? To me, it does not make sense at all.

 

[elm70]

All the time you are referring to the how nice it would be to have something like the BMW 2-speed drive. And how other hybrid cars have a complete gearbox. How are these less complex that a straightforward parallel drive? To me, it does not make sense at all.

Yes, probably I'm not having being clear.

For me, the two best approach are:
- The most simple .. Serial mode only .. 1 single EV gear ... ICE not connected to the wheels.
- The most complex ... Parallel mode only (but no serial support) .. traditional gerabox, and ICE in line with EV motor ... EV motor can be used as generator for increase the load of ICE , as start up engine for ICE, , and for EV pure mode drive.. (actually this is maybe the most simple to adapt .. it does only need an EV engine between ICE and gerabox, with 1 additional clutch)

The Outlander PHEV .. is something in between, or maybe just something else .. or extra complexity compared to the "most simple" one

But .. for go from "feeling" to "facts" .. it should be needed to know the cost of each part and the weight and dimension of them.

PS: I don't know how many gears have the bmw i3 ... I guess is not really relevant .. actually single gear with EV motor should be the most simple (cheap and resilient) approach

 

[ian4x4]

elm70 wrote Why i3 ICE power is too little for your point of view ?
I think the ICE power should be dimensioned exactly for the average power need by the car for normal usage, plus a little extra buffer (up to +25%) .. the buffer also need to be extended in case the size and limit of the battery pack of the car. So .. i3 ICE is perfectly dimension in my view

The BMW i3 is a perfect example of how to design a lightweight, efficient, battery electric driven vehicle, with quite a good range.

It has a largish battery which drives the wheels directly and has only one gear.
The small 'scooter' engine is ideal for recharging the battery, unfortunately it struggles a bit once the main battery runs out and it is faced with a long motorway incline.

The i3 owners forum has discussed this at length, for example;
http://www.mybmwi3.com/forum/viewtopic.php?f=13&t=3870&p=34024&hilit=reduced+power#p34024

If you could scale the i3 up to a large SUV, it would probably gain a lot of weight and need a huge battery. It's present lowest weight is a major part of its efficiency, so it may not work as well.

I think your idea for downsizing to a small turbo petrol may be the way to go, especially as we have a high voltage battery available to speed up the turbo from start up to full power. (as used by Volvo [and F1 race cars])

How would you design your perfect SUV if you didn't use the Outlander as your basis?
or how would you improve the design yet preserve the existing Outlander architecture (chassis, battery position, motor lay out etc.)?

I think a lot of us on this forum are looking for the perfect SUV.

 

[anko]

Yes, probably I'm not having being clear.

For me, the two best approach are:
- The most simple .. Serial mode only .. 1 single EV gear ... ICE not connected to the wheels.

Still not clear to me. I don't see why serial mode without direct drive would be better than serial mode with direct drive. Like you said, all it needs is one additional clutch. By what standard would it be better? Definitely not fuel economy.

 

[elm70]

Still not clear to me. I don't see why serial mode without direct drive would be better than serial mode with direct drive. Like you said, all it needs is one additional clutch. By what standard would it be better? Definitely not fuel economy.

Right ..

The only direct drive issue that I can find .. it is if this is going to dictate the selection of the engine .. a "poor" petrol block aspirated ... neither powerful nor efficient ... it is looking a poor decision.

Back to "ian4x4" ... "question" ...

Given that for me the outlander is too big ... the ASX would have been my choice if available in PHEV mode ... more then SUV .. what I'm after is 4x4 and decent ground clearance ... needed for winter security and avoid to remove snow at my home (drive over 20cm of snow is faster then remove snow by "hand")

Anyhow ... this is what I would have took as power train:

1.6D turbo diesel engine from ASX
Combined generator with EV motor .. so ICE and front EV motor inline .. with 2 clutches " ICE - clutch - EV - clutch - front differential
Rear EV motor as current PHEV

This set up will avoid 1 EV motor (current PHEV has 3: 1 generator and 2 pure motion EV "engine") ... and should make up space and "money" for use a "turbo".

Direct gear from ICE .. should be tuned for have 3600rpm (max power) at ~ 165km/h .. that means max torque (1750rpm) will be around 80km/h ... so ... motorway economy should be way better

Other option will be to use 18kwh .. this will allow 50% more EV power, for have more "dynamic" car usage.

PS: Using this approach .. serial mode .. is possible only in RWD ... but does not sound a big issue to me.

 

[maby]

All the time you are referring to the how nice it would be to have something like the BMW 2-speed drive. And how other hybrid cars have a complete gearbox. How are these less complex that a straightforward parallel drive? To me, it does not make sense at all.

Yes, probably I'm not having being clear.

For me, the two best approach are:
- The most simple .. Serial mode only .. 1 single EV gear ... ICE not connected to the wheels.
- The most complex ... Parallel mode only (but no serial support) .. traditional gerabox, and ICE in line with EV motor ... EV motor can be used as generator for increase the load of ICE , as start up engine for ICE, , and for EV pure mode drive.. (actually this is maybe the most simple to adapt .. it does only need an EV engine between ICE and gerabox, with 1 additional clutch)

The Outlander PHEV .. is something in between, or maybe just something else .. or extra complexity compared to the "most simple" one

But .. for go from "feeling" to "facts" .. it should be needed to know the cost of each part and the weight and dimension of them.

PS: I don't know how many gears have the bmw i3 ... I guess is not really relevant .. actually single gear with EV motor should be the most simple (cheap and resilient) approach

How about the Toyota solution? ICE and a decent power motor/generator coupled into two ports of a three way differential. By varying the relative power outputs of the two drive sources you can get an almost infinitely flexible drive pattern ranging from pure ICE to pure EV. The Prius can run pure ICE right down to walking pace and pure EV up to close to 70mph provided there is charge in the battery.

 

[jaapv]

The Prius comes with a CVT. That allows the engine to remain coupled to virtually standstill, but introduces its own transmission loss.