Mitsubishi Outlander PHEV Forum

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 Post subject: Re: So why do we have Hybrid Electric Vehicles.
PostPosted: Sun Jan 06, 2019 1:39 am 
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Joined: Mon Dec 03, 2018 8:47 am
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Location: Southern end of North Yorkshire, UK
I completely agree - the aim is to run the petrol engine in its most efficient range, hence limited rpm range and use the electric drive system to control the amount of torque and speed of the wheels. If the engine had a bit more torque and the generator (and associated circuitry) could handle higher currents then parallel mode wouldn’t be needed at all, like it is on some other hybrids (lighter, smaller and 2WD though). As battery and motor technology continues to improve I imagine this is where HEV and PHEVs will go. Then maybe ditch petrol/deisel and switch to a cleaner fuel (LPG, hydrogen?) until the infrastructure exists for a full pure EV world.

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2015 Mitsubishi Outlander PHEV GX4H (petrol/electric)
1991 Mitsubishi Pajero 2.5 LWB (WVO)
2008 Volkswagen Caravelle (diesel)
(recently departed - 2004 Subaru Outback 3.0Rn (LPG))


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 Post subject: Re: So why do we have Hybrid Electric Vehicles.
PostPosted: Sun Jan 06, 2019 1:57 am 
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Joined: Wed Jul 11, 2018 4:35 pm
Posts: 141
Location: Saratoga, CA
elm70 wrote:
My why is relative common:

- This car allow to make my daily commute in EV mode, which means spending 4 time less then using fuel.

But ... the reason why I bought this PHEV, it was because 2nd hand was relative cheap, and it was a nice update from my previous diesel SUV

The plus is an excellent economy for daily commute
The cons, is that consumption at speed 130km/h or more is very high .. which is normally my speed on long trip (which often I do with my old BMW 335i for have more speed and better fuel economy)

PS: A pure EV make sense for a 2nd car ... not only the infrustructure in most of europe is not ready for EV, but I'm also not ready to spend 45min or more waiting for charging the car.

PS: If I would have to design a PHEV .. I would follow the i3 REX example ... a bigger battery (25/30kwh) with a smaller ICE (40kw ICE I think is enough), but with a bigger fuel tank compared to the micro tank on the BMW i3


You wanna know who screwed up the i3 REX? The California Air Resources Board. https://insideevs.com/bmw-i3-rex-bevx-r ... leash-rex/ I would just pull out a couple of quotes but the entire article is interesting. And the BEVx rules are really dumb (and it explains exactly why they are so dumb).


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 Post subject: Re: So why do we have Hybrid Electric Vehicles.
PostPosted: Sun Jan 06, 2019 2:20 am 
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Joined: Wed Jul 11, 2018 4:35 pm
Posts: 141
Location: Saratoga, CA
Trex wrote:
Now what did Toyota do to achieve, or not, the excellent fuel efficiency as stated as a core development concept.

Well first they had to have a goal of how much more efficient than a conventional car they wanted. Toyota stated for their new Prius:

"Fuel efficiency 1.5 times the conventional car wasn't good enough―we needed to double it,"

So we need to get that into perspective here. Toyota with the Prius wanted to go from approx 7.2 lts/100kms (Edit this was in 1994) they could achieve with say a comparably sized car like the Toyota Corolla to approx 3.6 lts/100kms with the Prius.

Well did they? Toyota state:

"The proudest accomplishment of the team was the achievement of 28 kilometers per liter under the Japanese 10-15 test cycle."

Well I do not know about anybody else but I am impressed. 28 kilometers per liter is approx 3.6 lts/100kms . 8-)

So how did they achieve it? Well Wikipedia state:

"ICE torque output is minimal at lower RPMs and conventional vehicles increase engine size to meet market requirements for acceptable initial acceleration. The larger engine has more power than needed for cruising. Electric motors produce full torque at standstill and are well-suited to complement ICE torque deficiency at low RPMs. In a power-split hybrid, a smaller, less flexible, and more efficient engine can be used. The smaller engine, using a more efficient cycle and often operating in the favorable region of the brake specific fuel consumption map, significantly contributes to the higher overall efficiency of the vehicle."

I think we can see what they are saying here. My simplified interpretation. Use a smaller engine, an Atkinson cycle engine in Toyota's case, to cover average loads when cruising and back it up with electric motors and a battery. Then we have regen and stop/start technology to also help efficiency and emissions.

But why go to all this trouble? Some might say we have losses going into and out of the drive battery. That cannot be efficient. A larger battery to degrade......... I could go on but still why go to all the trouble? Just what is the problem with the the ICE (Internal Combustion Engine) that we need to address.

The sad truth. It is inefficient. Wikipedia state:

"In the past 3–4 years, GDI (Gasoline Direct Injection) increased the efficiency of the engines equipped with this fueling system up to 35%."

Now this claim:

"Most internal combustion engines are incredibly inefficient at turning fuel burned into usable energy.

The efficiency by which they do so is measured in terms of "thermal efficiency", and most gasoline combustion engines average around 20 percent thermal efficiency. Diesels are typically higher--approaching 40 percent in some cases.

Toyota has now developed a new gasoline engine which it claims has a maximum thermal efficiency of 38 percent--greater than any other mass-produced combustion engine."

Lets just say the ICE is approx 40% efficient just remember that is maximum thermal efficiency. Sitting at the traffic light idling a big V8 it will not be 40% efficient. Only when it is in the favourable region of the brake specific fuel consumption map will we be seeing this. In this region the throttle plate that controls the air that comes into the pistons to be burnt with fuel is fully open and so reduced pumping losses.

Lets get our heads around this. At least 60% losses. :shock: and according to Toyota most gasoline combustion engines average around 20 percent thermal efficiency. 80% losses. :o The 15-20% losses we talk about around here in the conversions of electricity are starting to sound low to me.

To be continued.............


But you make it sound like 40% efficiency is horrible, when in fact it is not. Even if you could make a perfect engine https://www.e-education.psu.edu/egee102/node/1942, it wouldn't be anywhere near 100% efficient, unless you somehow exhaust the gases into a temperature sink at absolute zero. 45-50% is really the best you can hope for even in the best conditions in an engine that does not have isothermal expansion and compression (takes too long) and is essentially adiabatic only.

Now as far as downsizing the ICE is concerned, this is NOT necessary to take advantage of HEV technology, and IMO Toyota overdid it, especially in the Prius. The Prius isn't a PHEV, and has a small battery, which gets quickly exhausted when climbing steep hills. Thus, the ICE should still be designed to match peak load when climbing, not average load when cruising. Whoever designed the thing must not have ever had to climb long slopes. But still, all else being equal, a HEV will have better efficiency than a comparable performance ICE only car, even if both vehicles can do 0-60 in 4.5 seconds, simply because the HEV can keep the engine in its optimal power band for much more of the time, and can recover energy when braking.


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 Post subject: Re: So why do we have Hybrid Electric Vehicles.
PostPosted: Sun Jan 06, 2019 3:00 am 
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Joined: Sat May 19, 2018 7:01 am
Posts: 41
Location: Los Angeles, CA, USA
HEV is no always about the efficiency. Look at this $2.2 Mi Mega Car:
https://en.m.wikipedia.org/wiki/Koenigsegg_Regera
Where Batt+Motors are for torque! The “simplicity” of a power train without transmission comes as a bonus.
Just imagine we mod the PHEV engine to EVO spec (330kW) paired with 2x350kW motors. It would be considered as a Mega(Watt) car as well.
Tai

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 Post subject: Re: So why do we have Hybrid Electric Vehicles.
PostPosted: Sun Jan 06, 2019 1:42 pm 
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Joined: Thu Feb 26, 2015 5:58 pm
Posts: 735
Location: Near Port Macquarie Australia
AndyInOz wrote:
95% of my usage is electric only. That other five percent would require a second car.


We get approx 90% EV with both our PHEVs


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 Post subject: Re: So why do we have Hybrid Electric Vehicles.
PostPosted: Sun Jan 06, 2019 1:44 pm 
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Joined: Thu Feb 26, 2015 5:58 pm
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Location: Near Port Macquarie Australia
Tipper wrote:
When asked about the drive system on my PHEV I always liken it to a 'diesel-electric locomotive'...with an added battery...and charging capability. This seems to satisfy most technically minded people. ;)


Yea series mode is pretty well exactly that IMO.


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 Post subject: Re: So why do we have Hybrid Electric Vehicles.
PostPosted: Sun Jan 06, 2019 2:05 pm 
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Joined: Thu Feb 26, 2015 5:58 pm
Posts: 735
Location: Near Port Macquarie Australia
richr wrote:
And the economy even with a depleted drive battery is still easily three-four times better than my 15 year old Subaru Outback 3.0 would do on my short commute.


Yea I still think it is amazing what hybrids can do and I have owned 4 of them. I had a BMW 5 series that could get 30 mpg imperial and I thought that was fantastic. It was smaller (less drag), less weight and a 2wd as compared to the PHEV but the PHEV for me comfortable beats it and, like you, that is not counting the grid charge.


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 Post subject: Re: So why do we have Hybrid Electric Vehicles.
PostPosted: Sun Jan 06, 2019 2:33 pm 
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Joined: Thu Feb 26, 2015 5:58 pm
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Location: Near Port Macquarie Australia
elm70 wrote:
PS: If I would have to design a PHEV .. I would follow the i3 REX example ... a bigger battery (25/30kwh) with a smaller ICE (40kw ICE I think is enough), but with a bigger fuel tank compared to the micro tank on the BMW i3


I cannot stand how the i3 looks. It just looks too different to me. Which over here would be an attraction for the anti EV and hybrid brigade to key it (scratch it using their keys) while you were not around. That's why I like the PHEV. It looks the same as the standard Outlander with just minor differences that goes mostly unnoticed over here.

I do not need a bigger battery as I am already carrying around battery that's probably about twice as big as needed for our average purpose. The PHEV as is serves us very well and that is why I have bought 2 of them but I look forward to any improvements like the Atkinson cycle petrol motor, longer life drive batteries etc.

Edit From memory the i3 Rex runs only in series mode from memory. So less efficient IMO.


Last edited by Trex on Sun Jan 06, 2019 4:48 pm, edited 2 times in total.

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 Post subject: Re: So why do we have Hybrid Electric Vehicles.
PostPosted: Sun Jan 06, 2019 2:41 pm 
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Joined: Thu Feb 26, 2015 5:58 pm
Posts: 735
Location: Near Port Macquarie Australia
maby wrote:
These are becoming increasingly difficult to find these days - the majority of so-called automatics I've seen recently are really servo operated manual transmissions.


We can still find cars over here without having a dual-clutch or DSG (direct-shift gearbox) or even the CVT transmission but they are getting rarer I think.


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 Post subject: Re: So why do we have Hybrid Electric Vehicles.
PostPosted: Sun Jan 06, 2019 3:18 pm 
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Joined: Thu Feb 26, 2015 5:58 pm
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Location: Near Port Macquarie Australia
HHL wrote:
A diesel can still be better!


I would consider that debatable HHL. My old Prius on a trip to Sydney could beat comparatively sized diesels at the time I owned the Prius from my research BUT that could have changed now.

But we must remember there is more energy in a litre of diesel than a litre of petrol so the Prius it at a disadvantage IMO.


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