MjThind

Sup 3RX gang! I have one gripe with my RX, it hunts for sixth and overdrive way to often. Now let give you an example when I am leaving school, I have to get on the freeway(traffic time) and almost everyday it kicks into overdrive or sixth, usually overdrive, mid-ramp and then I have to press the accelerator at least a good 75% to get acceleration. But the low end torque is stupendous, has good get go from starting from a stop. I tried driving in sequential for a week but one to many things to divide my attention with when I have to think of solution on a whim if someone calls from my dads office and some one calls me almost everyday as soon as the dismissal bell rings at school, so it didn't work out to long... Does this happen to anyone else???
Thanks in Advance
-MjThind

corradoMR2

Not really. I avoid distractions and focus on driving.

But on your real question, can't comment on the 6-speed, but the 8-speed in the F-Sport, one needs to hit the throttle on a merge for passing power I guess similar to yours. But in my experience with many vehicles I've owned, this is a more common "issue" with 6-speed or more gears.

rayaans

The party trick of the 450h - Press the accelerator and instant torque!!

Dolphin

I can't follow the problem you are trying to express...are you asking about driving distractions, or the way the trannie is performing?
If it's the trannie, my 6 spd, if it slips into OD, aka gear 6, at low speeds, and you want fast acceleration, like all auto trannies, you must nail the gas pedal to downshift to lowest possible gear for max. acceleration. Going up a gradual hill at about 35-40mph is prob. the weak link in this scenario, as the car will fall into high gear, AND, acceleration is hampered by both the hill and the amount of downshifting that occurred.

Interesting side note... I drove a 2013 Nissan Murano, which like the 450h, has a gearless trannie, i.e. two opposing conical shaped pulleys with a belt / that runs between them. The belt moves to keep the engine in its power band, supposedly maximizing fuel economy and smoother trannie, since there are no gears. First, the fuel economy is worse than the RX, and secondly, much to my surprise, I did NOT like this trannie. It felt lacking...I did not have the control that I am used to with basic auto trannies. It felt like a golf cart vs. a car. I drove the 450h many years ago, for a short ride, and don't recall if it reacted the same as the Nissan. Seems these gearless trannies, people either love em, or dislike them. I would think as technology develops though, they will become the new standard in all autos. So much simpler, and potentially more cost effective with longer life expectancy and lower maint cost. I am surprised it hasn't dominated the auto market by now. Interesting, how some technologies like tablets advance at warp speed, as they went from obscurity to outselling laptops in 3 yrs, and other technologies have a very slow development and implementation curve.

vlad_a

Well, technically speaking, Toyota Hybrids don't have a transmission. They call it Hybrid Synergy Drive. Used to be Power Split Device. There are no cones, clutches or torque converters. Two electric motors both propel the vehicle and act as a rotational variation device for the ICE.
One of electric motors is directly connected to the driving wheels.
In AWD, a 3rd electric motor drives the rear wheels.

That's why it feels different than CVT and is so responsive.

MjThind

I was actually talking about the tranny response, but interesting CVT side note I loved my dads old dd GS450h power...

MjThind

Super interesting thanks for shedding some light...

vlad_a

Sure thing! Can you tell I really love the technology behind Toyota hybrids?
It's so simple and yet ingenious at the same time.

BTW, Ford uses the same type of a hybrid - they exchanged patents with Toyota, where Toyota got the European Diesel and Ford got the Hybrid. That's how IS220d came to life. IMHO, wasn't a fair exchange.

Dolphin

Vlad, fully agreed, I should have differentiated, my post was confusing....was making a few points in a single post.

Hybrids in gen. are direct drive, an electric motor drives the wheels, quite simple. The engine and brakes recharge the batteries. In the end, still, no gears.

Hybrids benefit from allowing an engine to ALWAYS run in its most efficient condition when recharging the batteries...which can not happen when the engine is used for the sole source of mechanical nrg to the wheels. If you want to see the benefit of this feature of a Hybrid, compare the hwy mgp of the hybrid vs. non hybrid, remarkably, they are very quite similar. This is due to losses in all the steps the hybrid goes through, from generation, transmission of electricity, storage losses, heat losses, 2nd elect. motor eff. losses, etc. The real gains come from harnessing the wasted heat nrg in the braking system. In a non hybrid, the brakes convert mechanical nrg (inertia) to waste heat, while the hybrid converts the braking nrg to electrical nrg. Hence why hybrids eff. gains are a result of mostly start / stop driving. Anyway, I could go on forever about this being in the nrg design field my entire life....sorry for the slight tangent.

My original premise was....why CVT type trannies have not prevailed in the marketplace... instead, they have nearly stalled vs. geared trannies. This is an example of stalled technological advancement...or possibly market response.

vlad_a

You're thinking of a series hybrid. Toyota is a full hybrid (ingenious, I tell you!). The engine has a direct mechanical connection to the wheels through a planetary gear set together with 2 electric motors. It is more efficient than to generate the electricity and feed an electric motor to propel the vehicle on electric power alone, as there are less power losses.
GM found this out the hard way with the Volt. Their initial designs were to build an Extender Range Electric vehicle, but they ended up with a plug-in Prius. They tried hard to hide this very fact.

You do make a good point about CVTs. You'd think there would be more of them. From everything I read, there's only a handful that are well-executed. To me, it makes more sense to have a CVT than a 10-gear transmission that has to constantly hunt for the right gear.

TripleL

One thing I'll mention here because is works on my IS very well is that I find if I want to accelerate like is being described here that the speed of my throttle input can force a 1 or even 2 gear kick down immediately.

What I mean is if i lean on the gas pedal and continue to push it further the car will accelerate and may or may not down shift a gear depending on speed/grade etc.

But, If I'm cruising along and then I quickly push down the gas pedal a mare inch; 9 times out of 10 the car will down shift immediately and pull away at which point I can either depress more or let up a little. The electronic throttle must sense the speed of input because an inch is not a lot of movement in the gas pedal yet it reacts.

Now it might just be based on my driving style as I do tend to be a feather foot but might be worth trying.

Dolphin

> Toyota is a full hybrid (ingenious, I tell you!). The engine has a direct mechanical connection to the wheels through a planetary gear set together with 2 electric motors. It is more efficient than to generate the electricity and feed an electric motor to propel the vehicle on electric power alone, as there are less power losses.


My point still stands.... Yes, I agree with you above, just did a refresh course on the 450h hybrid. However, where is the net gains? It all comes out in the wash, when you view net fuel economy....
~27 mpg hwy for both hybrid and non hybrid RX.

So, there is NO efficiency benefits for hwy driving, even though the full hybrid system has eff gains in certain sub components. Their is compensatory losses that negate any gains, net effect = zero.

So nearly all the eff. gains of hybrids come from what I mentioned in my previous post, braking regeneration. Are we on the same page?

DunWkg

Some of you might enjoy some of the video(s) from Weber State University for :

vlad_a

Hybrids have a slight weight disadvantage compared to their non-hybrid counterparts. The weight of the electric motors is offset by not having a transmission.
The goal of the hybrid is to improve fuel efficiency. Here's a few ways I can think of:
1) Running the engine at more optimal RPMs while either storing excess energy in the battery or depleting it
2) More fuel efficient Atkinson cycle vs Otto; Not possible without #1
3) Even when idling the energy is regenerated and stored in the battery; no idling when stopped and the engine is warm; no torque converter drag on the engine when stopped
4) Coasting downhills charges the battery
5) Braking energy recuperation
6) No mechanical link to the rear motor (AWD), negating the need for a center diff

I disagree that the net effect is zero. I noticed during the winter, people complained about getting 15MPG in the RX350, while RX450h gets about 25. On short trips in the loaner RXs, I never got over 19MPG.
The both the main and hybrid sub-forum have a threads dealing with real life numbers. As it warmed up, I'm up to 29MPG now.

Will the extra cost of the hybrid be recovered during its ownership? The answer is no. However, same could be said about buying a vehicle with a larger engine or better transmission, except the hybrid is also lighter on gas.

Cruiter

Yes, and no. By definition the transmission is transmitting the power from the power source to the wheels and we have that. However.... as explained below, Hybrid means two sources of power. We have the ICE, and the electric motor generators. For the front wheels which are the primary driving force it's both. If you watch the display you'll see examples where the wheels are driven by gas only, battery only, AND both. Now if you have the AWD, the rear wheels get power from the battery/electric motors 'only' when they are used which is only when needed. The AWD h is still primarily a front drive in normal use. I do like the link you provided, it's a good description. The following is copied from Lexus.

What are the characteristics of a Hybrid engine?
This design features the engine mounted in the front of the vehicle and driving the front wheels. In the case of a hybrid front-wheel drive vehicle-the term “hybrid” means there are two different sources of power. Current hybrid vehicles have both an internal combustion powered engine (like a conventional automobile) and an electric motor.

What exactly is a hybrid? How does it work?
Lexus hybrid technology uses the combination of an internal combustion engine of a conventional gasoline-powered vehicle and the battery and electric motor of an electric vehicle. This combination offers low emissions and high fuel economy, while maintaining the power, extended range and convenient fueling capability of conventional vehicles.

What are the characteristics of a Hybrid All-Wheel Drive vehicle?
With the Lexus Hybrid Synergy Drive AWD system, there is no driveshaft connecting the front and rear axles. Power at the front axle is supplied by the split parallel/series hybrid system, and power to the rear axle is generated by a separate 50 kW electric motor.

How/when does it switch from gas to electric? Can I switch on demand?
Depending on load requirements and driving conditions, Lexus hybrid technology switches automatically from gas to electric, or a combination of the two power sources. This function cannot be switched on demand.

Here's the link to the whole article http://servcolexus.com/Distributor/L...ybrid&view=faq .

This is overly done and requires at the minimum 1/2 to full bottle of wine, brie and crackers and probably a runner to refresh the 1st helping , but it's very educational 'if you watch it through'.

3rd Generation Toyota Hybrid (eCVT) Transaxles - YouTube