Interesting article into how are hybrid system operates

[berry802]

I posed a question in the maintenance section in reference to the electric motor / K0 clutch housing and the maintenance required in the future (oil change interval/type)Electric motor maintenance question .

After digging around looking for answers I came across the article below about the Tundra hybrid system (similar to ours w/different engine), and while it did not answer my question it did educate me on how our system operates. Being this is my first hybrid it was a worthwhile read.


The rebirth of the parallel hybrid powertrain

 

[Nuke]

Great article! Two things which bother me are the relays to switch power on/off, and a starter with a mandatory service life. Good grief, this day & age there are solid-state devices to replace mechanical relays.

 

[MJE]

Great article! Two things which bother me are the relays to switch power on/off, and a starter with a mandatory service life. Good grief, this day & age there are solid-state devices to replace mechanical relays.

I didn’t catch the part about the relays. I did see the starter life though. 384,000 starting events. I wonder what that translates to in an expected service life? The last time I had to replace a starter in a vehicle it was a 90s Chevy truck that was about 9 years old at that point. Could that many starting events, even with this on/off stuff nowadays, give a decade of service life? About what you used to expect from one anyways?

 

[TheBat]

I didn’t catch the part about the relays. I did see the starter life though. 384,000 starting events. I wonder what that translates to in an expected service life? The last time I had to replace a starter in a vehicle it was a 90s Chevy truck that was about 9 years old at that point. Could that many starting events, even with this on/off stuff nowadays, give a decade of service life? About what you used to expect from one anyways?

It kind of sounds like you could just reset the counter and carry on when you reach 384,000 if you wanted to roll the dice. Or at least by then someone will have figured out the hack to do something like that.

 

[TheBat]

Great article! I'm not sure how the Tundra operates but the description of moving under motor power until 25 mph when the engine kicks in is certainly not how the LC operates. Unless that is a theoretical max speed on motor alone, either way it makes sense that there would be some differences from the Tundra.

 

[rickc5]

Great article! I'm not sure how the Tundra operates but the description of moving under motor power until 25 mph when the engine kicks in is certainly not how the LC operates. Unless that is a theoretical max speed on motor alone, either way it makes sense that there would be some differences from the Tundra.

Agree that the LC doesn't work like that. If you're sensitive to slight bumps, you can actually feel the gas engine kick in as soon as the LC starts moving from a dead stop. You can really feel the gas engine shutting off as you almost come to a dead stop--kind of a bump.

 

[TakaraLC]

I didn’t catch the part about the relays. I did see the starter life though. 384,000 starting events. I wonder what that translates to in an expected service life? The last time I had to replace a starter in a vehicle it was a 90s Chevy truck that was about 9 years old at that point. Could that many starting events, even with this on/off stuff nowadays, give a decade of service life? About what you used to expect from one anyways?

Probably forever. 384,000 starting events is for the backup starter, which is only used if there is an issue with the hybrid system or if it is unavailable for some reason. Even if we say the regular stater is used 5 times per day (where the actual number is probably 0), it will last 210 years.

 

[MJE]

Probably forever. 384,000 starting events is for the backup starter, which is only used if there is an issue with the hybrid system or if it is unavailable for some reason. Even if we say the regular stater is used 5 times per day (where the actual number is probably 0), it will last 210 years.

I like your logic & way of thinking. i did notice though that the 12V starter is also used in temps below 5F. That’s too often here. But I agree, realistically even if it was used at every stoplight on your commute (where the cold would likely disable the auto start/stop anyways) you’re still likely beyond the expected vehicle life.

I think if I was to be worried about this starter failing, I’d need to be more worried about eventual hybrid battery failure (not sure if the truck would continue to operate as a non-hybrid in that scenario). Even then I’m not too worried about that given how long Toyota has been doing hybrids. Undoubtedly some will run into the error scenario, then I think it’s as Bat said. You can reset the light & take your chances if you wish.

 

[Valsmere]

Interesting article, thank you for sharing. I was a little nervous purchasing my 58. I’m not a big fan of being an early adopter of a new, first year model. However remembering that I had a first year FJ and she was solid. Also realizing that the Land Cruiser is THE flag ship model for a Toyota SUV and that Toyota wouldn’t mess with that I expect our Cruisers to be around for a long long time. Maybe I’m being naive, most likely not, there are high expectations for these suvs. At the end of the day only time will tell, I have faith. Meanwhile I’m enjoying the hell out of my new ride!

 

[Captain Trips]

Here is Toyota video talking about they’re explaining the iforce max

 

[Valsmere]

Here is Toyota video talking about they’re explaining the iforce max

Oh cool thanks for the post! I will check it out.

 

[HarvLC]

Agree that the LC doesn't work like that. If you're sensitive to slight bumps, you can actually feel the gas engine kick in as soon as the LC starts moving from a dead stop. You can really feel the gas engine shutting off as you almost come to a dead stop--kind of a bump.

My LC starts the gas engine upon my applying a certain amount of throttle. It is not merely based on the vehicle moving. Stopped and with the engine having shut off, I can release the brake and the vehicle will roll using the electric motor. Sometimes I can apply the slightest bit of throttle and continue to move forward via the electric motor. But typically, the gas engine starts as I’m easing into the throttle.

 

[katekebo]

Here is a simple diagram that explains how the iForceMax hybrid system works and the 4 basic operating modes.
There is a "5th" mode, not show on the diagram, which happens when the gas engine needs to be started while the vehicles is stationary. In this case, it is the conventional starter that is used to start the gas engine, while the K0 clutch remains disconnected.

As a maintenance item, it's important to note that the K0 clutch and the MG sit in a separate housing from the automatic transmission (and torque converter). Hence, when changing transmission fluid, one should also drain and refill the K0 clutch housing.

Finally, this is how the iForceMax drive works in the US LC, Tacoma, Tundra and Sequoia. It is different from the mild hybrid 48V system used in some other markets.

 

[Nuke]

It was my understanding the K0 clutch could be optioned even when stationary via the shown electric oil pump, i.e. the starter would not be needed, and that the conventional starter is only for extremely hard start conditions, such as with sub-zero temperatures.

 

[katekebo]

It was my understanding the K0 clutch could be optioned even when stationary via the shown electric oil pump, i.e. the starter would not be needed, and that the conventional starter is only for extremely hard start conditions, such as with sub-zero temperatures.

It's a bit more complex. Yes, MG is used in most situations to start the gas engine. But there are some exceptions:

• When the hybrid battery is low (which will also covers the low temperature condition)
• First start after opening and closing the fuel door. This is to ensure that the starter gets "exercised" from time to time and doesn't seize due to lack of use.
• When the car is stopped in Drive (or Reverse), the gas engine is off and needs to be restarted without moving the car (brake pedal is depressed). This is because the MG is always connected mechanically to the pump side of the torque converter, and spinning the MG to start the gasoline the engine could result in unexpected vehicle movement if the brake pedal is only gently pressed. This isn't a very common situation, but happens occasionally when the gas engine is cold-ish or the hybrid battery is at a low state of charge, and the vehicle is stopped for longer-then-normal time in Drive, without shifting into Neutral or Park.

 

[Nuke]

Thank you! I had forgotten about when the fuel door is opened. An ingenious system...

 

[ovʀʟxnᴅ]

I'm not sure how the Tundra operates but the description of moving under motor power until 25 mph when the engine kicks in is certainly not how the LC operates. Unless that is a theoretical max speed on motor alone, either way it makes sense that there would be some differences from the Tundra.

I think your idea is more along the lines of functionality in the real world. Creeping off the brakes in a drive-thru, you can move under battery power, but if you touch the accelerator, the engine cuts on.

 

[D-Train]

For those of you who are wondering how the turbo works with the battery system, this is a great description!

 

[Paul2660]

I have a 2025 and believe that you can easily drive on the battery up to speeds of 31mph, depending on the conditions. Slight downhills in my neighborhood for example. I am basing this only on fact that I 0 RPM's showing and the I have my foot on the accelerator. More commonly I see battery only 0-20mph on flat or down grades, again basing this on 0 RPM's showing and the fact what when I hit an uphill or need to accelerate more a slight push on the pedal and you can feel the engine kick in and the RPM gauge goes back to over 1K.
However on some HWY 2 lane driving at over 60MPH I have also watched the RPM gauge drop to 0, again I assume I am on battery (on long downhills). However many times the truck will down gear for the hill (similar to how my 4 runner worked) and this of course kicks in the engine. It seems dependent on the steepness of the hill/speed I am at/whether the truck allows battery only or wants engine braking.

Everyone has their own style of driving, so it's going to be a personal type of thing.

Paul C

 

[cvx5832LC]

The conditions where the vehicle goes electric-only is most likely very complex. That said I've seen it go electric-only twice at 68mph, and once at 74mph. Both slightly downhill, foot off the pedal or just slightly depressing it.

I cannot do it deliberately, just happens when it happens.