2009 GS450h hybrid battery reliability?

Lwerewolf · March 29, 2021

2 hours ago, Steven Lockey said:

1> If Lexus said that and they specifically state that either can power the car entirely independently and it's not true, they could and would of been sued by now.
2> You can see on the console what the hybrid system is doing and if the electric motors are running at all. It tells you on the central console (if it's in the right display mode) exactly what the system is doing. Only time I've seen it generate extra electric power was when my battery was dodgy. It also shows whenever the electric is adding power. I don't think they would make the system lie.
3> I've read that people disabled the hybrid system entirely (no complete circuit) and the car was still drivable. Not 100% sure on that as its just something random people said on the internet.
4> It may be the generator can draw variable amounts of power, much like it does under braking. So under standard operation its only drawing similar amounts of current to what the alternator on a normal car does?
5> Not sure what you mean about been directly attached to the road wheels.... no car has the engine directly attached to the road-wheels, that's what the gear-box does. What you are describing is when the car is in neutral. Is this was the case the car would only ever be able to output the electric power of the motors.

Done a bit of reading up, it does look like the generator is constantly running but just draws as much power as it needs. Reading the guide to the hybrid system it claims there is a power-splitter which can vary how much power goes to the wheels and how much to the generator.

"In normal driving, engine output is divided by the Power Split Device to drive the wheels directly and to power the generator, which in turn drives the electric motor and simultaneously charges the high-voltage battery. In these circumstances, power allocation is constantly monitored and adjusted between engine and motor to maximise efficiency"

They do actually say here its optimised for smoothness of acceleration as well, which would imply they sacrifice some of the performance they could get. In addition I think as the electrics work best at near 0 mph and the ICE works best over 40 mph, it may be that neither can output their max at the same speeds.

Hard to read, looks like most of this is translated from japanese (badly lol).

This might be different on the IS300H

1) Bold claim 🙂

2) You can see a whole lot of nothing from the console. Get hybridassistant if you want useful live system information and very good logging to boot.

3/4/5) Read up on how this car works.

https://slideplayer.com/slide/14432904/

Same transmission, without the LF1A transfer case. Certainly the same ratios - the "new car features" for the gs450h service manual is wrong in some places on sun/planet/ring gear teeth - basically states an impossible arrangement, conveniently the digits were just swapped or something. The EU-spec 450h has 245/40/18 tyres and a 3.266 diff. This is enough info for you to plot the RPM relationships between the motors and the engine at different speeds.

The prius and pretty much every single toyota hybrid is almost the same. The GS has a 2-stage auto for MG2 and an FR drivetrain. Pretty much all serious discussions re: the prius apply.

The inverter is actually an AC-DC-AC converter with an additional buck-boost converter that is connected to the Battery. The converter is rated at 35kw. The AC-DC-AC converter handles the electrical (i.e. "series hybrid") path for the engine's power, and can use the Battery to boost to or regen from the AC motors.

Some data (the mg2 rpm column is way to the left, sorry):

Sample acceleration data, with the gear shift visible (look for the mg2 rpm switch at ~12k, gps speed is lagging badly):

Sample cruising data, with SOC<60%:

Sample cruising data, with SoC at 60%:

Don't remember the details, probably with AC on, low beams (it's a highway), music, potentially cruise control.

The ICE is RPM-limited (and respectively, somewhat power-limited, but not too much) by the max RPM of MG1 at certain speeds - it takes approximately 140kph before MG1's top speed (12.5k rpm) stops limiting the engine. The ICE is also power-limited by MG2's powerband.

A good analysis of the motors can be found here:
https://www.osti.gov/biblio/947393

The motors are the same (ignore the stated RPM limit on MG2).

Anyways, @Thackeray is on to something 😉

Steven Lockey · March 29, 2021

2 hours ago, Lwerewolf said:

1) Bold claim 🙂

2) You can see a whole lot of nothing from the console. Get hybridassistant if you want useful live system information and very good logging to boot.

3/4/5) Read up on how this car works.

https://slideplayer.com/slide/14432904/

Same transmission, without the LF1A transfer case. Certainly the same ratios - the "new car features" for the gs450h service manual is wrong in some places on sun/planet/ring gear teeth - basically states an impossible arrangement, conveniently the digits were just swapped or something. The EU-spec 450h has 245/40/18 tyres and a 3.266 diff. This is enough info for you to plot the RPM relationships between the motors and the engine at different speeds.

The prius and pretty much every single toyota hybrid is almost the same. The GS has a 2-stage auto for MG2 and an FR drivetrain. Pretty much all serious discussions re: the prius apply.

The inverter is actually an AC-DC-AC converter with an additional buck-boost converter that is connected to the battery. The converter is rated at 35kw. The AC-DC-AC converter handles the electrical (i.e. "series hybrid") path for the engine's power, and can use the battery to boost to or regen from the AC motors.

Some data (the mg2 rpm column is way to the left, sorry):

Sample acceleration data, with the gear shift visible (look for the mg2 rpm switch at ~12k, gps speed is lagging badly):

Sample cruising data, with SOC<60%:

Sample cruising data, with SoC at 60%:

Don't remember the details, probably with AC on, low beams (it's a highway), music, potentially cruise control.

The ICE is RPM-limited (and respectively, somewhat power-limited, but not too much) by the max RPM of MG1 at certain speeds - it takes approximately 140kph before MG1's top speed (12.5k rpm) stops limiting the engine. The ICE is also power-limited by MG2's powerband.

A good analysis of the motors can be found here:
https://www.osti.gov/biblio/947393

The motors are the same (ignore the stated RPM limit on MG2).

Anyways, @Thackeray is on to something 😉

1> Car companies that makes claims which are easily disproved are rarely not sued by someone 🙂

2> Its a very high level overview yes. I've got something similar which plugs into the OBD port and records performance. I've not used it in a while but I'm pretty sure it was telling me that the electric wasn't constantly running.

3/4/5> Honestly, why did you think I was digging through tech manuals???
However everything I'm reading supports what I said!

The first link you posted seems to support what I was saying. See slide 6:
"The power split device distributes the engine power as appropriate to directly drive the vehicle as well as the generator."
Emphasis mine. Its not constantly running mg1 as a generator and pushing with mg2. I know some older hybrids did that, most of them couldn't use the engine directly power directly to the roads at all, the ICE was only there to power the generator. This is 100% certainly not the case with the GS450h.

Also I find it slightly hard to believe the tables you posted. Not saying they are necessarily wrong, just the numbers may not mean what you think they mean, or they may be reporting potentials rather than 'it does do this'.

According to them your MG2 even when cruising is draining the Battery as its using more kw than the MG1 is producing constantly even when cruising. That 100% isn't right cos otherwise my Battery would be empty on my long motorway runs and it isn't. And I'm pretty sure they aren't BOTH running as generators as that would make no sense for one having negative torque numbers and the other not.

Even then, when cruising the MG1 was generating 1-2KW of power.... which is basically enough to run the AC and other bits inside the car I would guess. I mean boiling a kettle can use up to 3KW so that seems like its basically running as a standard alternator at that point.

I never said the car can't or wouldn't do this, just that it doesn't do it all the time and doesn't constantly take the same fixed % of power from the ICE, your tables clearly support what I was saying as you can see for example on the one where you are cruising at 93 (mph? kph? no idea 😉 ), at the start, the engine power is 31.34 and mg1 is 4.2, 1 second later the engine power is at 39.96 but mg1 has dropped to 0.18.
That would be literally impossible if what Thackney has said was true. mg1 kw would always be a direct multiple of the engine power.

I'm sure when the car is in the range where using the electrics is more optimal it will do exactly that.

Steven Lockey · March 29, 2021

The wiki page also seems to agree with me:
https://en.wikipedia.org/wiki/Hybrid_Synergy_Drive

(yes I know its wiki 😉 But it's yet another source agreeing with me)

And I've found the issue. Its the Battery, the standard Battery does have a max output of 52BHP/39KW,
so for the electrics to provide more, it uses MG1 to provide the extra charge when its in a range where the electrics are more efficient. The electrics themselves can handle far more power (they have to for regenerative braking, I assume they can charge faster than they can discharge, most can).

Also explains why mine is a bit quicker since I don't have the standard Battery, I got an uprated 3rd party one 🙂
Again I forgot about that bit in a previous post about electric only acceleration but apparently according to the specs mine has a maximum output of 53KW.

Steven Lockey · March 29, 2021

3 hours ago, Lwerewolf said:

The inverter is actually an AC-DC-AC converter with an additional buck-boost converter that is connected to the battery. The converter is rated at 35kw. The AC-DC-AC converter handles the electrical (i.e. "series hybrid") path for the engine's power, and can use the battery to boost to or regen from the AC motors.

Just re-read this.... WHAT????
That's just not right.... The only reason to convert AC-DC-AC would be to change the frequency which has VERY rare applications!

Also an inverter and a converter are complete opposites..... there is no such thing as a AC-DC-AC converter or inverter. One does AC-DC the other does DC-AC. The inverter (for the traction engine) is rated at 250KW.

The convertor as far as I can see is just used to provide power for the electronics.

I know it's been 20 years since I took my electrician qualification but that seems very wrong!

ColinBarber · March 29, 2021

There are two convertors, one that takes the hybrid Battery voltage and boosts it to a max of 650 VDC. The other reduces the hybrid Battery voltage to around 14 VDC for the vehicle electrics.

The inverter takes the 650 VDC from the boost convertor and converts that into 3 phase AC to power the electric motor.

The convertors use a switching design with transistors.

The AC-DC-AC part is when the AC generated by MG1 (being driven from the ICE) is converted to DC and then back to AC to drive MG2. It is precisely because of a frequency change is required. This is all taken care of within the inverter.

Thackeray · March 29, 2021

6 hours ago, Steven Lockey said:

I've found the issue. Its the battery, the standard battery does have a max output of 52BHP/39KW,

Well that's very gratifying! That's almost exactly the guess I made in my first post above. Thanks for doing the research to find out the details.

As regards the power split device, here's a useful animation. I posted this a month or two ago in a different thread but if you haven't seen it before it's an interesting representation of the Toyota/Lexus transmission.

Steven Lockey · March 29, 2021

5 hours ago, ColinBarber said:

There are two convertors, one that takes the hybrid battery voltage and boosts it to a max of 650 VDC. The other reduces the hybrid battery voltage to around 14 VDC for the vehicle electrics.

The inverter takes the 650 VDC from the boost convertor and converts that into 3 phase AC to power the electric motor.

The convertors use a switching design with transistors.

The AC-DC-AC part is when the AC generated by MG1 (being driven from the ICE) is converted to DC and then back to AC to drive MG2. It is precisely because of a frequency change is required. This is all taken care of within the inverter.

Ah, thats not a 'Convertor' thats a 'Boost Convertor' they are very different things in electronics 🙂

Steven Lockey · March 29, 2021

3 hours ago, Thackeray said:

Well that's very gratifying! That's almost exactly the guess I made in my first post above. Thanks for doing the research to find out the details.

As regards the power split device, here's a useful animation. I posted this a month or two ago in a different thread but if you haven't seen it before it's an interesting representation of the Toyota/Lexus transmission.

Yep, thats a good video.

The only bit you said I was disagreeing with was the fix % electrical draw from the engine. That video shows where it locks the centre cog, so mg1 stops turning and the ICE drives then directly turns the outer-ring on the planuar cogs.

So basically, you could get a lot more power but you'd need to install much bigger voltage Battery and bypass the boost convertor (no easy job) and probably rewrite a LOAD of the ECU.

Lwerewolf · March 29, 2021

12 hours ago, Steven Lockey said:

The first link you posted seems to support what I was saying. See slide 6:
"The power split device distributes the engine power as appropriate to directly drive the vehicle as well as the generator."

That statement is the same statement like:

Quote

A mono-tube type shock absorber generates a damping force starting with an extremely low piston speed range. Thus, it realizes a natural and linear vehicle behavior in response to driving maneuvers and a flat ride comfort. Furthermore, the proper response and continuity of the shock absorber damping force have been ensured. This minimizes useless unsprung movement to ensure the proper road tracking capability and ride comfort.

...from the "new car features" section on the monotubes.

What does it tell you? Practically nothing - "we're using a monotube, we're super duper cool". Later on it does show a digressive tune and the bleed port setup (and the double pistons acting as a "main piston", but it doesn't say why they're used).

Anyways, look for the "how", which leads me to:

12 hours ago, Steven Lockey said:

Also I find it slightly hard to believe the tables you posted. Not saying they are necessarily wrong, just the numbers may not mean what you think they mean, or they may be reporting potentials rather than 'it does do this'.

According to them your MG2 even when cruising is draining the battery as its using more kw than the MG1 is producing constantly even when cruising. That 100% isn't right cos otherwise my battery would be empty on my long motorway runs and it isn't. And I'm pretty sure they aren't BOTH running as generators as that would make no sense for one having negative torque numbers and the other not.

Even then, when cruising the MG1 was generating 1-2KW of power.... which is basically enough to run the AC and other bits inside the car I would guess. I mean boiling a kettle can use up to 3KW so that seems like its basically running as a standard alternator at that point.

Power figures in the tables are absolute. Look at the torque - negative in the "cruise" scenario.

Would it theoretically be possible for MG2 to regen and for MG1 to push?

http://prius.ecrostech.com/original/PriusFrames.htm

How the ECU reports "positive" or "negative" torque numbers is another story - you might want to look here:
https://openinverter.org/forum/viewforum.php?f=14&sid=1e7a76c446e71061f34dc8cb44526c2b

Several mentions in the gs450h vcu discussions regarding how you give "negative" torque requests to mg1 to get it to move forwards with mg2.

Finally:

12 hours ago, Steven Lockey said:

I never said the car can't or wouldn't do this, just that it doesn't do it all the time and doesn't constantly take the same fixed % of power from the ICE, your tables clearly support what I was saying as you can see for example on the one where you are cruising at 93 (mph? kph? no idea 😉 ), at the start, the engine power is 31.34 and mg1 is 4.2, 1 second later the engine power is at 39.96 but mg1 has dropped to 0.18.
That would be literally impossible if what Thackney has said was true. mg1 kw would always be a direct multiple of the engine power.

It's KPH, the limit on the road is 140KPH if you're wondering.

You're referring to this:

Frame 2 > 3, in particular.

The car is trying to raise the revs from ~1550 to ~1850, which means that the motor has to let off for a bit.

12 hours ago, Steven Lockey said:

Also explains why mine is a bit quicker since I don't have the standard battery, I got an uprated 3rd party one 🙂
Again I forgot about that bit in a previous post about electric only acceleration but apparently according to the specs mine has a maximum output of 53KW.

How exactly have you told the car what your "uprated" Battery is uprated too?

Have you also "uprated" the buck/boost converter?

How have you measured the "a bit quicker" part?

11 hours ago, Steven Lockey said:

Just re-read this.... WHAT????
That's just not right.... The only reason to convert AC-DC-AC would be to change the frequency which has VERY rare applications!

Also an inverter and a converter are complete opposites..... there is no such thing as a AC-DC-AC converter or inverter. One does AC-DC the other does DC-AC. The inverter (for the traction engine) is rated at 250KW.

The convertor as far as I can see is just used to provide power for the electronics.

I know it's been 20 years since I took my electrician qualification but that seems very wrong!

Google "AC-DC-AC converter" and then "AC-DC-AC inverter" and tell me which term should I use.
Two inverters sharing the capacitor bank, that can also get power from the Battery via a buck-boost converter.

There's also the DC-DC (HV->12V) converter next to the Battery, the AC drive, the power steering drive, the auxiliary oil pump drive, potentially the active stabilizer inverters... anyways.

The ORNL article that I linked previously also goes into how the "inverter" (PCU) is arranged. The GS450h one is almost the same as the "camry" one (investigated in an earlier ORNL article - https://www.osti.gov/biblio/928684-evaluation-toyota-camry-hybrid-synergy-drive-system), filling the missing transistor slots.

The Lexus Enthusiast · March 29, 2021

On 3/27/2021 at 11:36 PM, Steven Lockey said:

Could always find one in a different colour and have a wrap applied?

I've thought abut that but overall I think it just adds cost and time so guess it's probably better to wait for the right one to come along which I hope it does soon. Thanks for suggestion though.

Thackeray · March 29, 2021

2 hours ago, Steven Lockey said:

That video shows where it locks the centre cog, so mg1 stops turning and the ICE drives then directly turns the outer-ring on the planuar cogs.

Exactly! This is what I meant when I said that the car can't move on engine power alone.

For the engine power to reach the road wheels the sun gear (centre cog) has to stop turning. But unlike a conventional automatic gearbox that has clutches to lock or unlock cogs in the planetary gearsets the Lexus power split device has no clutches. Instead it has electric motors that can go forwards or backwards or be fixed in a stationary position. But all these options require electricity. Turn off the electricity and the cog wheels will spin freely.

So without electricity, the sun wheel can't be locked and the planets (attached to the engine) will also spin freely and won't move the car. That's what I meant when I said the engine can't propel the car on its own. It needs the electric motors to create resistance which will transfer the torque to the road wheels.

Steven Lockey · March 29, 2021

9 minutes ago, Lwerewolf said:

Power figures in the tables are absolute. Look at the torque - negative in the "cruise" scenario.

Yes that was my point... so your Battery would be flat by cruising since MG2 is outputting more power than MG1 is generating according to those tabes.

12 minutes ago, Lwerewolf said:

What does it tell you?

That smaller shocks are more effectively dampened. Makes sense to me....

I realise you aren't in the UK so not sure on your local laws, but in the UK if they say something that would in common language be interpreted that way, they are liable and can be sued, so they are generally VERY careful to not do that.

14 minutes ago, Lwerewolf said:

How the ECU reports "positive" or "negative" torque numbers is another story - you might want to look here:
https://openinverter.org/forum/viewforum.php?f=14&sid=1e7a76c446e71061f34dc8cb44526c2b

Yeah... I'm not reading the entire forum.... that just links to the forum index.

Given what we've seen since about the Battery limits, what I thought was right.

16 minutes ago, Lwerewolf said:

The car is trying to raise the revs from ~1550 to ~1850, which means that the motor has to let off for a bit.

Which is exactly what I saw saying, the car can change the amount of power MG1 draws from the ICE, which is exactly what your tables show.

18 minutes ago, Lwerewolf said:

How exactly have you told the car what your "uprated" battery is uprated too?

Have you also "uprated" the buck/boost converter?

How have you measured the "a bit quicker" part?

No idea, the guy who fitted it did the work.... not me. Hes an experienced Lexus engineer and quite a few people on this forum have used him and I've not seen any complaints.

Fairly sure the boost converter hasn't been touched.

It may just be the fact the old Battery was dodgy so it's just operating at potential now, that was the reason for the Battery swap. I measured a noticable (0.4s) 0-60 improvement over several runs with Traction control off, not sure how reliable the numbers are but it feels quicker.

Numbers were based off OBD reports so not 100% reliable. May be that not all the power has to run through the boost convertor as even the basic Battery has more potential output than the boost convertor can handle.

22 minutes ago, Lwerewolf said:

Google "AC-DC-AC converter" and then "AC-DC-AC inverter" and tell me which term should I use.
Two inverters sharing the capacitor bank, that can also get power from the battery via a buck-boost converter.

Again, no such thing in electronics as either. Converter and inverter are very specific terms meaning quite specific things as is Boost Converter. Neither do AC-DC-AC as that would be pointless. All the googling I can see if this is just a name someone has given to a combination of an inverter and a boost convertor, which are entirely separate components electronically even if they get built into the same unit.

28 minutes ago, Lwerewolf said:

DC-DC (HV->12V) converter

Nope, thats a boost converter, not a converter. Slightly confusing but they are very different things.

Thackeray · March 29, 2021

16 hours ago, Lwerewolf said:

Some data (the mg2 rpm column is way to the left, sorry):

Sample acceleration data, with the gear shift visible (look for the mg2 rpm switch at ~12k, gps speed is lagging badly):

Interesting to compare the first table where the accelerator is at 100% (foot to the floor), with the one where the accelerator is at 22%.

MG2 is showing high levels of positive torque in the first (maximum acceleration) but negative torque in the other. I'm guessing this is the so-called "heretical mode" that baffled some Prius forums in the early days of the Prius.

This is when MG2 changes from a motor, driving the road wheels, to a generator. The electricity produced is transferred to MG1 to run as a motor instead of a generator and this allows the petrol engine to run more slowly when cruising on a motorway. A sort of overdrive.

Steven Lockey · March 29, 2021

1 minute ago, Thackeray said:

Exactly! This is what I meant when I said that the car can't move on engine power alone.

For the engine power to reach the road wheels the sun gear (centre cog) has to stop turning. But unlike a conventional automatic gearbox that has clutches to lock or unlock cogs in the planetary gearsets the Lexus power split device has no clutches. Instead it has electric motors that can go forwards or backwards or be fixed in a stationary position. But all these options require electricity. Turn off the electricity and the cog wheels will spin freely.

So without electricity, the sun wheel can't be locked and the planets (attached to the engine) will also spin freely and won't move the car. That's what I meant when I said the engine can't propel the car on its own. It needs the electric motors to create resistance which will transfer the torque to the road wheels.

Ok, but if the Sun wheel is locked, then there is no electric been generated.... Which was what I was saying, didn't say it didn't require any electric power AT ALL.... spark plugs need power as well!

Lwerewolf · March 29, 2021

How do you lock the sun gear?

Steven Lockey · March 29, 2021

3 minutes ago, Thackeray said:

Interesting to compare the first table where the accelerator is at 100% (foot to the floor), with the one where the accelerator is at 22%.

MG2 is showing high levels of positive torque in the first (maximum acceleration) but negative torque in the other. I'm guessing this is the so-called "heretical mode" that baffled some Prius forums in the early days of the Prius.

This is when MG2 changes from a motor, driving the road wheels, to a generator. The electricity produced is transferred to MG1 to run as a motor instead of a generator and this allows the petrol engine to run more slowly when cruising on a motorway. A sort of overdrive.

Makes sense.

Steven Lockey · March 29, 2021

6 minutes ago, Lwerewolf said:

How do you lock the sun gear?

Which one? The GS450h has 3.

Prisus have either 1 or 2.

Lwerewolf · March 29, 2021

14 minutes ago, Steven Lockey said:

Ok, but if the Sun wheel is locked, then there is no electric been generated.... Which was what I was saying, didn't say it didn't require any electric power AT ALL.... spark plugs need power as well!

6 minutes ago, Steven Lockey said:

Which one? The GS450h has 3.

Prisus have either 1 or 2.

As for:

14 minutes ago, Thackeray said:

Interesting to compare the first table where the accelerator is at 100% (foot to the floor), with the one where the accelerator is at 22%.

MG2 is showing high levels of positive torque in the first (maximum acceleration) but negative torque in the other. I'm guessing this is the so-called "heretical mode" that baffled some Prius forums in the early days of the Prius.

This is when MG2 changes from a motor, driving the road wheels, to a generator. The electricity produced is transferred to MG1 to run as a motor instead of a generator and this allows the petrol engine to run more slowly when cruising on a motorway. A sort of overdrive.

Notice that both mg1 and mg2 torques are "positive" or "negative" at the same time. Goes hand in hand with my comment re: looking at what torque commands it takes for the inverter to drive both motors in such a way as for the car to move forward without engine power - assuming that the planets fork (i.e. the engine) is welded to the transmission chassis.

In other words - you can probably think as "all positive" - non-overdrive, "all negative" - overdrive ("heretical").

Steven Lockey · March 29, 2021

How on earth should I know lol, I'm not a mechanic.

Either way if the cog is locked, the MG1 isn't generating power cos it isn't spinning which is what I said.

Lwerewolf · March 29, 2021

7 minutes ago, Steven Lockey said:

How on earth should I know lol, I'm not a mechanic.

Either way if the cog is locked, the MG1 isn't generating power cos it isn't spinning which is what I said.

14 minutes ago, Steven Lockey said:

Which one? The GS450h has 3.

Prisus have either 1 or 2.

So which one is it?

You can lock the ring gear with the parking pawl. You can obviously lock some gears in the 2-speed gearbox for MG2 via the two clutch packs.

There is no way to mechanically lock the sun gear.

What you're trying to say (the "engine" being the only thing sending motive power to the wheels) can only happen if mg2 is generating just enough power to keep the 12v system on, and if that much "push back" from regeneration is enough for the PSD to send everything else coming from the engine to the wheels. Doesn't really happen under "normal" driving conditions - the car would rather keep the engine "off" during such low loads, for efficiency purposes.

Steven Lockey · March 29, 2021

4 minutes ago, Lwerewolf said:

So which one is it?

You can lock the ring gear with the parking pawl. You can obviously lock some gears in the 2-speed gearbox for MG2 via the two clutch packs.

There is no way to mechanically lock the sun gear.

What you're trying to say (the "engine" being the only thing sending motive power to the wheels) can only happen if mg2 is generating just enough power to keep the 12v system on, and if that much "push back" from regeneration is enough for the PSD to send everything else coming from the engine to the wheels. Doesn't really happen under "normal" driving conditions - the car would rather keep the engine "off" during such low loads, for efficiency purposes.

Or there is this thing cars have called batteries?

Can easily lock mg1, detach mg2 and bang it runs on the ICE and the electronics run from the Battery.

Again, I don't think this is what happens, it looks like the MG1 is capable of drawing the amount it needs from the ICE via the power-splitter, there are many mechanical and electrical ways of doing this, which will basically increase the resistance of the sun-cog to turning.

Your own charts show the MG1 only generating 1-2 KWs when cruising, not enough to power the MG2 effectively. At those levels that sounds like its just powering the electronics.

At lower speeds where the ICE is less efficient and the traction engine is more efficient, sure it'll pull more from MG1 and pump it to MG2 as well as using the ICE. I only said it doesn't do this ALL the time. I'm sure it does do this when you are cruising around 20-60 mph (very approx). Certainly at the motorway speeds I've been going at (cough cough), this doesn't seem to have been the case, nor when you were cruising at 140kph.

Lwerewolf · March 29, 2021

6 minutes ago, Steven Lockey said:

Your own charts show the MG1 only generating 1-2 KWs when cruising, not enough to power the MG2 effectively. At those levels that sounds like its just powering the electronics.

"Heretical" mode. MG2 generating, MG1 "motoring". Overdrive. Mentioned several times during the past few hours. I'm really having trouble maintaining a decent tone.

Anyways.

Lock the sun gear, disconnect MG2 (not that it matters much) and now you have a direct gear to the wheels. The whole point of the CVT is for the engine to be able to operate with optimal BSFC at all times.

Steven Lockey · March 30, 2021

5 hours ago, Lwerewolf said:

Lock the sun gear, disconnect MG2 (not that it matters much) and now you have a direct gear to the wheels. The whole point of the CVT is for the engine to be able to operate with optimal BSFC

That is exactly what I was saying.....

And you've been arguing with....

I said the exact same thing one post up......

Lwerewolf · March 30, 2021

1 hour ago, Steven Lockey said:

That is exactly what I was saying.....

And you've been arguing with....

I said the exact same thing one post up......

You didn't catch my drift again.

Let me rephrase:

A CVT (whatever the implementation) is used to be able to keep the engine at its optimal running condition (with regards to BSFC = brake-specific fuel consumption) for whatever load is required of it.

If you lock up the sun gear mechanically (somehow) and disconnect MG2 (again, somehow), you have a direct gear to the wheels. This linearly maps engine RPM to road speed.

This is about the worst thing that you can do in terms of overall efficiency, unless all you do is drive at a constant speed on a constant incline with constant everything else that may affect engine load requirements.

I've reread the thread (for some weird reason) and I think you might want to read up on how the eCVT works. Preferably not from marketing material and without focusing on generalizations----I mean, blanket statements such as "The power split device distributes the engine power as appropriate to directly drive the vehicle as well as the generator."

Steven Lockey · March 30, 2021

1 hour ago, Lwerewolf said:

A CVT (whatever the implementation) is used to be able to keep the engine at its optimal running condition (with regards to BSFC = brake-specific fuel consumption) for whatever load is required of it.

Yes agreed

1 hour ago, Lwerewolf said:

If you lock up the sun gear mechanically (somehow) and disconnect MG2 (again, somehow), you have a direct gear to the wheels. This linearly maps engine RPM to road speed.

You are the ONLY person who has mentioned mechanically locking the sun gear, no-one else has.

1 hour ago, Lwerewolf said:

This is about the worst thing that you can do in terms of overall efficiency, unless all you do is drive at a constant speed on a constant incline with constant everything else that may affect engine load requirements.

Like say cruising down the motorway at high speed? Also you do realise that the efficiency of electric motors is reduced considerably at high speed? That kinda the point of the hybrid. The electrics work better at low speed, the ICE at higher speeds.

That's why for example the Tesla model 3 performance only has a max speed of 162 mph, despite been considerably lighter than the GS450h and having an extra 110 KW of power.

1 hour ago, Lwerewolf said:

Preferably not from marketing material and without focusing on generalizations----I mean, blanket statements such as "The power split device distributes the engine power as appropriate to directly drive the vehicle as well as the generator."

I'm confused, I took that from the link you posted.....
If its marketing material that isn't worth looking at, why did you post it?
And given its backed up by several other pieces of data... I'm confused about what you think is wrong.

The video Thackney posted has a really good explanation of why it does go into "direct-drive" mode, because converting mechanical power to electric and then back to mechanical power has an inefficiency attached to it.

I am NOT saying it doesn't utilize the MGs to optimise the engine efficiency when it thinks its appropriate either.

I mean this is basically what heretical mode is. The ICE is providing the power, MG2 is acting as a alternator and MG1 is used when/as needed to help the engine stay at peak efficiency levels. The car is still been driven directly by the ICE at this point.

You really seem to be arguing against things I haven't said and splitting hairs on other points. If this is due to me not explaining what i was trying to say clearly enough I apologise but I honestly think you are extrapolating from what I've said to mean things that aren't what I was saying.