I was reading a brochure for my 2010 Prius and it stated it had a 2-speed CVT with overdrive. After 50-K I have NOT felt it shift (2 speed) Or found how to shift to overdrive! Whats up with that??
Looking at the models of the Synergy drive (on YouTube etc), I can't see how. HOWEVER, the Wikipedia article (Hybrid Synergy Drive) says part way through: "In 2006 and 2007, a further development of the HSD drivetrain, under the Lexus Hybrid Drive name, was applied on the Lexus GS 450h / LS 600h sedans. This system uses two clutches (or brakes) to switch the second motor's gear ratio to the wheels between a ratio of 3.9 and 1.9, for low and high speed driving regimes respectively. This decreases the power flowing from MG1 to MG2 (or vice versa) during higher speeds. The electrical path is only about 70% efficient, thus decreasing its power flow while increasing the overall performance of the transmission. The second planetary gearset is extended with a second carrier and sun gear to a ravigneaux-type gear with four shafts, two of which can be held still alternatively by a brake/clutch. The GS 450h and LS 600h systems utilized rear-wheel drive and all-wheel drive drivetrains, respectively, and were designed to be more powerful than non-hybrid versions of the same model lines,[2][3] while providing comparable engine class efficiency.[26]"
That makes no sense. What exactly does it say? You must've misunderstood some advertising gibberish. There are some mechanical (belt-type) CVT transmissions with a 2-speed ratio change combined with the continuously variable mechanism, but not in Prii.
simple googling reveals this: 2016 Toyota Prius Hatchback Overview The standard features of the Toyota Prius Two include 1.8L I-4 121hp hybrid gas engine, 2-speed CVT transmission with overdrive, 4-wheel anti-lock brakes (ABS), side seat mounted airbags, curtain 1st and 2nd row overhead airbags, driver knee airbag, airbag occupancy sensor, automatic air conditioning, 15" aluminum wheels, cruise control, ABS and driveline traction control, electronic stability. 2016 Toyota Prius Hatchback Showroom | West Herr Auto Group - Buffalo, NY and many other similar dealership websites. doubt if this is accurate though. why? it makes sense. it's a "hybrid" between HSD and conventional AT to improve efficiency at high speeds, high loads in those bigger heavier cars.
I would say "not accurate at all". First, there is no 121hp hybrid gas engine. It is a 99hp Atkinson cycle engine. And there is no speed transition in the transmission, nor is it a CVT. I wonder who dreamt this up. If it is on more dealership websites it seems to be a concoction of Toyota US.
I can easily imagine some dealers cribbing from others. Or a group of them sharing web designs and information.
Repeat after me: West Herr is not Toyota. My dealer is not Toyota. Dealers are independent businesses. Many Dealers are clueless, a smaller number are deliberately duplicitous. Now, how did whoever wrote the OP's brochure get their 'facts'? When the Gen 3 came out it had a second planetary gearset, fixed to be a gear reduction, so M/G1 did not over rev. In an 'automatic' transmission you add additional planetary gearsets to get more speeds, so that could be the confusion. Arguably, the entire point of heretical mode is to act as an overdrive. But nothing mechanically changes when in heretical mode, the computers are just using M/G2 as a Generator and M/G1 as a Motor.
I don't see any relationship between the gear reduction on MG2 and the rpm of MG1. The MG2 gear reduction just lets them use a smaller MG2 motor while retaining MG2's torque contribution at the wheels. merged. The new RWD Cadillac CT6 hybrid transmission is roughly a 2016 Volt/Malibu design but adds a 3rd planetary gear set and 2 clutches on it that provides vaguely similar ability to switch between 2 output gear reductions. However, the reductions can be just on the equivalent of MG2 during EV-only driving or can also apply to the output of the power-split planetary kind of like a 2-speed version of the new Lexus LC500h with a 4-speed post-HSD automatic transmission. I think. I need to read the new SAE paper (2016-01-1150) more carefully.
The "Motoring Press" - enough said. I contacted a well respected motoring journalist a couple of years back when he compared a hybrid Camry with several other cars, one of which had a CVT (Nissan? or Subaru?) - the band drive type which, at the time had a less than stellar reliability and had high maintenance costs. In the article he said something like "both the Camry and the ***** have CVT transmissions". I suggested that he should have at least called it an eCVT, but better still a Hybrid Synergy Drive, otherwise the majority of readers would think that it used a band type CVT drive. He did respond, saying that in the article, he hadn't wanted to get into a technical discussion, but indicated that he did know the difference. Unfortunately, his readers may not.
you can get to 62 MPH before the In the first and second gen, M/G1 spun 2.6 times for every once M/G2 spun when the engine was off. so if you went over 42 MPH the engine HAD to start or you over reved M/G1. In gen 3, it is very close to one to one, so you can get to 62 MPH without starting the engine, and I do not think that limit is due to M/G1.
Regardless of what MG#2 is doing, MG#1 in the 3rd generation still has to turn 2.6 times per rotation of the ring gear when the engine is stopped, so the engine still must turn when the car speed is over about 45mph to avoid overreving MG#1. So Jeff N had it right.
Right, the gear ratio (tooth count) in the power-split planetary gear has remained constant between all Prius generations. The new item is that the max rpm of MG1 went from around 6,500 in the original Prius to around 9,500 in gen 2 and later and that is primarily why the engine-off speed increased (MG1 can spin faster in order to keep the engine on the planetary carrier from spinning). Another reason is battery power output. With a bigger battery and power output capability, the Plug-in Prius was able to take engine-off sped up to 62 mph. The 2016 Volt has a somewhat Prius-like design when the clutches are set for engine-off driving except that the gearing ratios and max "MG1" rpm is such that it can drive up to about 101 mph.
