In a little over a year, the new Lexus LC500 and LC500h flagship coupes go on sale. We got a quick look at the 500h hybrid ahead of its auto-show debut in Geneva. The hybrid won?t be in showrooms for quite a while, but when it does arrive, the one thing you are sure to never hear a salesman say about the hybrid is, ?this transmission is like a semi truck?s.? No one wants to hear that their potential new Lexus luxury coupe has anything in common with a Peterbilt. In reality though, they sort of do. Lexus?s new hybrid transmission, dubbed Multi Stage, is essentially two transmissions bolted up to one another: a Toyota hybrid CVT and an Aisin four-speed automatic, which is just like the dog-tooth manual and range selector found in a tractor-trailer?s 18-speed manual.
Before we dive in the shallow end of Multi Stage, lets have a quick primer on Toyota Hybrid Synergy Drive (HSD). Debuting in Toyota’s home market in the 1997 Prius as the Toyota Hybrid System, HSD’s concept is complex but the design is rather simple. HSD consists of an internal-combustion engine (ICE), two motor-generators (MG1 and MG2), and a planetary gear set (in some cases, multiple planetaries). MG1?s role is that of a generator and it also sets the reduction (gear ratio) by changing its speed, and acts as a starter for the ICE. MG2 is the traction motor, battery-limited to 60 horses in the LC500h, and is the primary harvester of regenerative-braking energy. These components are fundamentally ...