So why do we have Hybrid Electric Vehicles.

[Trex]

But you make it sound like 40% efficiency is horrible, when in fact it is not.

No I agree. 60% losses are good. So for every $1 of fuel I put in the engine I get 40 cents back in usable energy at the best. No you are right, that is good. :?

BUT you also said elsewhere:

First of all, each round trip through the battery costs about 10-20% in energy, at least. That's not efficient.

and

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.

So when the PHEV charges its drive battery to put it into its "optimal power band" (so it can shut down the ICE later) you say its inefficient but then you say "HEV will have better efficiency than a comparable performance ICE only car...because the HEV can keep the engine in its optimal power band". :? You are starting to sound a bit inconsistent I think or have I started to change your mind? IMO through research and learning it quite ok to admit you were wrong and change your mind about things.

In a thread where I am writing about Hybrid Electric Vehicles which is naturally comparing the advantages and disadvantages of different drivetrains ie electric and petrol most people here I would hope can see where I am going with that statement about the ICE being inefficient or as I say bloody inefficient.

 

[Trex]

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.

I think that it good to see that IMO in your statement there.

Like I said earlier in this thread:

Now why did Toyota produce the Prius which no matter what we think of them Toyota has sold millions. Edit approx 6 million up to 2016 from what I can see including all variants.

Notice that "all variants" I wrote there, well included in that is the Plug-in Prius and Prius Prime which I would consider to be PHEVs.

Now as a person that owned and driven a Prius climbing the Great Dividing Range here it was quite ok performance wise even once the battery was down but mine was a Gen 3 so it had the bigger petrol motor compared to previous models.

 

[Trex]

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

Hello fellow manly ute oops truck owner.

Yes that definition I put in my first post in this thread states "The presence of the electric powertrain is intended to achieve either better fuel economy than a conventional vehicle or better performance."

$2.2 mil. Can buy a lot of PHEVs for that.

Mega(Watt) :lol: :lol:

 

[STS134]

No I agree. 60% losses are good. So for every $1 of fuel I put in the engine I get 40 cents back in usable energy at the best. No you are right, that is good. :?

You've gotta compare to the best efficiency that is even possible, which is the Carnot efficiency. Then, you remove the isothermal expansion and contraction stages (not possible in a car engine, because the power to weight ratio of such an engine would suck) and you get some value for the maximum efficiency that is possible in a practical ICE. In that regard, 40% isn't that bad at all.

So when the PHEV charges its drive battery to put it into its "optimal power band" (so it can shut down the ICE later) you say its inefficient but then you say "HEV will have better efficiency than a comparable performance ICE only car...because the HEV can keep the engine in its optimal power band". :? You are starting to sound a bit inconsistent I think or have I started to change your mind? IMO through research and learning it quite ok to admit you were wrong and change your mind about things.

So...here's the thing. When I tell the PHEV to charge the battery, i.e., I put it in Charge mode, and it runs the ICE in a very efficient power band by using some power to propel the vehicle and some to charge, great. If I just ask it to Save battery power, and DO NOT want it to charge the battery, nor draw power from it, it would be much better if it simply lowered the ICE RPM to operate the ICE in at an efficient RPM for the power being demanded of it, that is, the power level required to propel the car only. Which would require a mechanical transmission to do.

In a thread where I am writing about Hybrid Electric Vehicles which is naturally comparing the advantages and disadvantages of different drivetrains ie electric and petrol most people here I would hope can see where I am going with that statement about the ICE being inefficient or as I say bloody inefficient.

Yeah but I think people overestimate how bad ICE efficiency is. At a power plant, the heat engine there is also limited by the Carnot efficiency, and while those engines aren't constrained by size or weight the way a vehicle engine is, such an engine suffers from transmission losses associated with sending power from the engine to the ultimate user of it over the grid.

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.

I think that it good to see that IMO in your statement there.

Like I said earlier in this thread:

Now why did Toyota produce the Prius which no matter what we think of them Toyota has sold millions. Edit approx 6 million up to 2016 from what I can see including all variants.

Notice that "all variants" I wrote there, well included in that is the Plug-in Prius and Prius Prime which I would consider to be PHEVs.

Now as a person that owned and driven a Prius climbing the Great Dividing Range here it was quite ok performance wise even once the battery was down but mine was a Gen 3 so it had the bigger petrol motor compared to previous models.

I'm guessing that you never tried to do a run up the Grapevine on I-5 (6% grade for 5 miles straight) at 80+ mph. https://priuschat.com/threads/highway-merging-uphills.124036/ People are reporting that it had trouble maintaining 60 mph with the accelerator floored once the batteries drained (post #20 and #21). That's the problem with sizing the ICE for average power AND having batteries that are insufficient to maintain peak power over the passes. The maximum speed I ever reached in my previous car up that grade though, was around 88 mph with the accelerator at WOT (wide open throttle) nearly the entire way up. I feel like the PHEV *could* do it, but you'd better have at least 60% charge when you get to the bottom (I only did around 75-80 mph up the grade last time because that's the speed at which most traffic was moving). At least Mitsu optimized the fixed ratio to generate maximum ICE power at 90 mph, which is great for running up the grade at high speed and actually getting maximum output from the ICE. But when you get to the top, expect your hottest cell to be at 34C with the cooling system running, even if it's cold outside. I wish it could do it without abusing the battery so much though.

 

[Trex]

You've gotta compare to the best efficiency that is even possible, which is the Carnot efficiency.

Au contraire. IMO I have not "gotta" even think about the Carnot cycle or efficiency which I covered in my engineering training over 30 years ago because in this topic I am comparing it to electric motors and batteries etc. Hence my statement :

If you have to start that petrol motor run it in its most efficient "zone" and at all other times try and turn the bloody inefficient petrol motor off.

Which I mean to be in EV mode when that bloody inefficient petrol motor is off. I hope that was clear to everybody.

 

[Trex]

I wish it could do it without abusing the battery so much though.

You can, by slowing down. Have you tried to force it into series mode? But you would have to be under about 120 kph.

Watch this video to see what I mean.
https://www.youtube.com/watch?v=rbOmtzFj14M

Watch center display between power gauge and speedo gauge and see how it goes from Series mode into Parallel mode at about 120kph.

 

[elm70]

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.

My previous BMW 320d was doing over 50mpg at 130km/h speed

If you care of fuel economy a diesel and a sedan offer superior economy

Since we opted for a SUV ... I guess fuel economy is a secondary factor.

 

[elm70]

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.

I did refer to i3 power system, not the look :ugeek:

A bigger battery will help not only on longer EV range, but as well on be able to provide more power (now it is limited to 70kw for the latest PHEV, old one has 60kw) ... as well, it will be less under stress and should be able to keep the SOH better then current PHEV which has a problem in this area

About series mode to be inefficient ... well ... it is in our current PHEV .. on a proper REX system I bet it can be quite efficient, if the small engine is tuned to deliver power at a given power level which is the ideal working load for this ICE

 

[STS134]

I wish it could do it without abusing the battery so much though.

You can, by slowing down. Have you tried to force it into series mode? But you would have to be under about 120 kph.

Watch this video to see what I mean.
https://www.youtube.com/watch?v=rbOmtzFj14M

Watch center display between power gauge and speedo gauge and see how it goes from Series mode into Parallel mode at about 120kph.

Yes but I've found that once it goes into parallel mode, it sometimes stays in parallel mode all the way down to around 80kph (50mph). While you'd think it would switch to series mode and rev up the engine because it's climbing, this is not always the case. Sometimes, it simply prefers to stay in parallel mode and consume battery to make up for the power that the ICE can't produce at that RPM.

 

[Trex]

I'm guessing that you never tried to do a run up the Grapevine on I-5 (6% grade for 5 miles straight) at 80+ mph. https://priuschat.com/threads/highway-merging-uphills.124036/ People are reporting that it had trouble maintaining 60 mph with the accelerator floored once the batteries drained (post #20 and #21).

Ok, finally had a chance to read that discussion on priuschat. Yep, never gone up the Grapevine on I-5 (6% grade for 5 miles straight) at 80+ mph in a standard Prius let alone a Prius C which is what the discussion was about . Now from memory the Prius C had a smaller petrol motor and drive battery. Mine was the standard Gen 3 Prius.

Now could the standard Prius go up the Grapevine at the speed limit? Not sure.

 

[Trex]

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.

My previous BMW 320d was doing over 50mpg at 130km/h speed

If you care of fuel economy a diesel and a sedan offer superior economy

Since we opted for a SUV ... I guess fuel economy is a secondary factor.

Ok. Over the lifetime of the PHEV, counting the grid charge, I would comfortable beat 50 mpg even if could travel at 130 kph for the approx 10% of the time I use the petrol motor on the PHEV. So to me fuel economy is not a secondary factor.

 

[Trex]

A bigger battery will help not only on longer EV range, but as well on be able to provide more power (now it is limited to 70kw for the latest PHEV, old one has 60kw) ... as well, it will be less under stress and should be able to keep the SOH better then current PHEV which has a problem in this area

Well the acceleration in EV mode for us (my family) is quite acceptable for what we use it for. Unless I was drag racing at the traffic lights I think it is good.

I think it is still too in early days to say "current PHEV which has a problem in this area". I have seen graphs of Tesla degradation where some people had quite bad deterioration in their batteries. Is that what we are seeing here with the PHEV? I do not know. But I do know we have another thread to discuss this.

 

[STS134]

Ok, finally had a chance to read that discussion on priuschat. Yep, never gone up the Grapevine on I-5 (6% grade for 5 miles straight) at 80+ mph in a standard Prius let alone a Prius C which is what the discussion was about . Now from memory the Prius C had a smaller petrol motor and drive battery. Mine was the standard Gen 3 Prius.

Now could the standard Prius go up the Grapevine at the speed limit? Not sure.

I'd imagine that it has a lot to do with how much cargo it's carrying. It might do okay with just one person in the car, but throw in a family of 4 and some suitcases in the trunk for a week at Disney and it'll probably struggle. In fairness though, A LOT of cars struggle to get up that slope...what makes cars like the Prius particularly bad though is that they have TWO max power levels: the boosted max, which is available when you initially start to climb, and then a much lower "battery dead" max that is much lower then the boosted max. And the batteries just aren't sized for a climb that steep and that long, so they quickly get exhausted and the car goes into "turtle mode". So if they size the system such that the boosted max gives it the power of a typical economy car, it quickly becomes a sitting duck in fast-moving traffic up slopes like the Grapevine. Personally, I'd give the Prius the same ICE power-to-weight ratio of a Corolla or similar car, with the boosted max being a bonus, so that it can at least keep up with economy cars when the batteries drain.

My Corolla could do 75-80 mph, but only at around 4.5-5.5k RPM and at WOT, when weighed down with that much stuff. My dad had a Nissan Pathfinder, which I drove up that slope, also with the entire family and luggage in the back, and I had the thing in 3rd gear (5 speed manual transmission) at around 5k RPM, and at WOT, all the way up, and it barely did 70-75. But then there's my friend's Cayenne S E-Hybrid, which can go up the Grapevine at 90 mph (a speed I've never managed to hit in any of these other cars, even when not loaded down) at 2k RPM without even breaking a sweat, without motor boost, on its 333 PS ICE alone. So yeah, there ARE advantages to oversizing the ICE and simply accepting being in less efficient regions of the consumption map most of the time. And there are disadvantages to it too: the thing is rated at just 19 mpg city/24 mpg highway/22 mpg combined. On the other hand, you don't want an engine so weak that it becomes a sitting duck in fast-moving traffic up a steep slope, nor do you want to severely overwork your engine, as that's detrimental to its lifespan. The only time I ever saw a full quart of oil disappear from my Corolla in about 750 miles involved a trip up the Grapevine, at WOT the entire way up. This was also the same trip where I had the engine at WOT many times on I-5, taking advantage of nearly every passing opportunity I saw in the flat areas, and it shows what operation at very high power levels and high RPMs does to your engine's ability to keep oil in the oil pan (not to mention, think about what it likely does to your piston rings!).

 

[Trex]

Yes but I've found that once it goes into parallel mode, it sometimes stays in parallel mode all the way down to around 80kph (50mph).While you'd think it would switch to series mode and rev up the engine because it's climbing, this is not always the case. Sometimes, it simply prefers to stay in parallel mode and consume battery to make up for the power that the ICE can't produce at that RPM.

Ok this statement, to me, is a little hard to understand. But I will try to explain how parallel mode works.

From what I have seen on my PHEV and elsewhere including that video I posted previously is the petrol motor stays in Parallel mode if it (and the drive battery) can provide the power requested of them and if not the petrol motor will go back into Series mode if you are under approx 120 kph. Over approx 120 kph the petrol motor can provide more power in Parallel mode so will switch to it (or stay in if over 120 kph) as seen in that video.

Hope that makes sense.

 

[STS134]

Ok this statement, to me, is a little hard to understand. But I will try to explain how parallel mode works.

From what I have seen on my PHEV and elsewhere including that video I posted previously is the petrol motor stays in Parallel mode if it (and the drive battery) can provide the power requested of them and if not the petrol motor will go back into Series mode if you are under approx 120 kph. Over approx 120 kph the petrol motor can provide more power in Parallel mode so will switch to it (or stay in if over 120 kph) as seen in that video.

Hope that makes sense.

ICE can provide enough power AND speed < 120 kph might be some of the initial conditions that cause parallel mode to come on (the other possible initial condition being speed over 125 kph), but once already there, it will sometimes stay there down to around 70-80 kph, even when the ICE is incapable of providing the power level requested. I'll try to get a shot of the instrument panel in this condition but I've had plenty of times when I was at around 70-80 kph with parallel mode engaged and the battery boosting.

 

[Trex]

Ok this statement, to me, is a little hard to understand. But I will try to explain how parallel mode works.

From what I have seen on my PHEV and elsewhere including that video I posted previously is the petrol motor stays in Parallel mode if it (and the drive battery) can provide the power requested of them and if not the petrol motor will go back into Series mode if you are under approx 120 kph. Over approx 120 kph the petrol motor can provide more power in Parallel mode so will switch to it (or stay in if over 120 kph) as seen in that video.

Hope that makes sense.

ICE can provide enough power AND speed < 120 kph might be some of the initial conditions that cause parallel mode to come on (the other possible initial condition being speed over 125 kph), but once already there, it will sometimes stay there down to around 70-80 kph, even when the ICE is incapable of providing the power level requested. I'll try to get a shot of the instrument panel in this condition but I've had plenty of times when I was at around 70-80 kph with parallel mode engaged and the battery boosting.

It is NOT just the power of the ICE. It is the ICE and the drive battery that combine to try and stay in parallel mode for power level requested. Remember it is a hybrid.

I will write it again hopefully clearer:

The ICE stays in Parallel mode if it (the ICE) and the drive battery COMBINED can provide the power requested of them and if not the ICE will go back into Series mode if you are under approx 120 kph. Over approx 120 kph the ICE can provide more power in Parallel mode so will switch to it (or stay in if over approx 120 kph) as seen in that video.

 

[Trex]

About series mode to be inefficient ... well ... it is in our current PHEV .. on a proper REX system I bet it can be quite efficient, if the small engine is tuned to deliver power at a given power level which is the ideal working load for this ICE

Ok I forgot to reply to this.

Now on Hybrid Electric Vehicles that are going used as a HEV ie using the petrol motor fairly regularly they go to the trouble of putting in a Parallel mode. Toyota's HSD come to mind as well Chevy Volt and our PHEV etc. Now they do not go to the added complexity of putting in clutches and such for no reason. It is to make the HEV more efficient than Series mode I would think. It virtually gives you a 2 speed gearbox in our case IMO.

 

[STS134]

ICE can provide enough power AND speed < 120 kph might be some of the initial conditions that cause parallel mode to come on (the other possible initial condition being speed over 125 kph), but once already there, it will sometimes stay there down to around 70-80 kph, even when the ICE is incapable of providing the power level requested. I'll try to get a shot of the instrument panel in this condition but I've had plenty of times when I was at around 70-80 kph with parallel mode engaged and the battery boosting.

It is NOT just the power of the ICE. It is the ICE and the drive battery that combine to try and stay in parallel mode for power level requested. Remember it is a hybrid.
...
I will write it again hopefully clearer:

The ICE stays in Parallel mode if it (the ICE) and the drive battery COMBINED can provide the power requested of them and if not the ICE will go back into Series mode if you are under approx 120 kph. Over approx 120 kph the ICE can provide more power in Parallel mode so will switch to it (or stay in if over approx 120 kph) as seen in that video.

Okay, THAT is consistent with what I am seeing:



This is a very dumb design IMO. The problem is, the system thinks the batteries are capable of supplying up to about 60 kW of power, and they are. It just isn't very good for their lifespan to do this so often, and instead of using the ICE whenever possible, it decides to kill the batteries. Now if my battery SoH goes below about 26 Ah before 10 years or 100000 miles are up, I won't mind so much. But after I get my free replacement, I want this thing reprogrammed.

 

[Tai626]

Do we (in the USA) get a free batteries replacement if it goes under 26Ah before 10year/100000miles? Probably only if we start posting mad videos in YouTube and get MMNA attention just like a transplant does in the south hemisphere...I am just considering this first battery pack stolen: paid by federal tax credit/California rebate/SoCal Edison/HOV sticker/gas saved.

Talking about the HOV, the old red sticker will expire in a couple of years. The new purple one will have one extra year. Most HOV heavy users will be getting a new car by then...Are you?

Even if not, within 10 years, the batteries technology would advance so much, that no one knows what battery we could get to transplant in our PHEV. By that time, hackers may have already decoded the firmware and we should be able to pay them to reprogram the car just like VW-TDI.

I just hope Mitsubishi sells more Outlander PHEV in the USA so I can get cheap battery packs in junk yard in the future. Last time I checked, those GM-Volt folks are getting battery pack for less than $3k! (Don’t ask me the SOH, please)

Meanwhile, we just enjoy our PHEV. Next time I go to SF Bay Area, let us have some beer to cheer for New Year!

Tai.

 

[STS134]

Do we (in the USA) get a free batteries replacement if it goes under 26Ah before 10year/100000miles? Probably only if we start posting mad videos in YouTube and get MMNA attention just like a transplant does in the south hemisphere...I am just considering this first battery pack stolen: paid by federal tax credit/California rebate/SoCal Edison/HOV sticker/gas saved.

Talking about the HOV, the old red sticker will expire in a couple of years. The new purple one will have one extra year. Most HOV heavy users will be getting a new car by then...Are you?

Personally, I don't think the Legislature is going to extend the Clean Air Decal program when all decals issued before January 1, 2022 are already expired and all decals issued after this date expire on September 30, 2025. The HOV lanes are already so clogged up with Teslas and Volts so as to make the stickers of limited usefulness at times, and by this time, EVs, PHEVs, and FCVs will no longer be rare enough to justify giving them special perks.