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This is my near 1:1 scale model of the second generation hybrid transaxle from Toyota, which is also used by Lexus and Suzuki, and similar to the system used by Ford.

I explain all of the components in this video, where I also show how it reflects the power flows when driving a hybrid car with this system. For this video I use the Lexus CT200h because... that's the one I have.


This is the full model:


In one end we have the 1.8 liter inline 4 piston engine:


The model is rather simple. There are no counterweights on the crankshaft, no oil pan, no valvetrain... etc. It pretty much just consists of the crankshaft, cylinders, conrods and pistons.


The pistons are, however, almost of the right bore:


and the stroke is also almost right. I am using the small 1x1 round tiles because the curved slopes have sharp edges that make the pistons jam within the cylinders:


The flywheel is super simple and bolts right onto the crankshaft:


In a real car there is what appears to be a clutch. It is, however, not a clutch. It is a damper with some springs that allow for a small amount of travel between the two sides. This is my not-very-accurate LEGO version of it:


The magic happens in the power split device which is flanked by the two motor/generators:


The LEGO model is powered by Power Functions motors:


In the center there are two planetary gears which are joined from the ring gears:



In the video I show how these components work together.

My hope is that this can help demystify the internals of the most popular hybrid system in the World. Many people think the hybrid system is rather complex, and Toyota doesn't help with its misleading "eCVT" naming. In reality this system has fewer moving parts than a DCT, slush-box automatic transmission or even manual, since there is no clutch, no traditional torque converter and no "real transmission".

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Ingenious, what a concept and very well presented. I really dig stuff like this, thanks.

And I actually learned about something that was previously a total mystery to me.

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Good job! I've seen plenty of 56T turntables used as ring gears, but never as planet gears until now!

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Thanks all. I'm glad that you like it. And please tell me if you want to see a LEGO version of the hybrid system with a 2 speed transmission, such as in GS450h or LS600h.

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