riwyle

This is my understanding of how it works. The heart of the powertrain is a planetary gear set which acts as a power splitter- i.e. it splits and controls between the internal combustion engine (ICE) and the electric motor the amount of power fed to the front wheels . This can vary between 100% ICE to 100% electric motor as conditions require.. On one side the ICE is connected to the planet gear spider, with its sun gear connected to a generator and its ring gear to the front wheels. From the other side the electric motor is connected in effect directly to the common ring gear. By varying engine load, sun gear driven generator load and speed, and motor loading, power is split and controlled between the ICE and the electric motor. This is all done continuously without shift points.
Rear wheels are driven solely by a separate electric motor.
On breaking, the drive electric motor(s) act as a generator to recover some of the energy.
If I am in error on anything, please someone correct me or fill in gaps I have omitted, especially on the control aspects. I believe the Lexus web site has some interactive displays demonstrating this.

BobBass

The only error I see is your use of the word "breaking" when you should have used "braking." This is one of the most common mistakes one encounters on automotive message boards and, as a former teacher, it "breaks" my heart.

Bear60

Interesting note: The AC motors can be turned into generators by simply changing the frequency which can be done quickly by the controller. The speed of the motors are also controlled by changing the frequency. The torque is changed by changing the pulse-width and the voltage sent to the motors. Lots going on and I appreicate the thousands of hours or programming that went into the design of the RX 400h. We got millions of dollars of engineering for just $3000 more than a standard vehicle. What a deal.

sirCharles

girlfriend get 27 mpg on her 400h. seems to be fairly good.

Kostyan

hey nobody on here yet explained to me how do you guys get better highway mileage in RX400h when after 40 mph eletric motors shut down and the RX runs on pure gas engine. B y the way, it is a detuned 3.3L motor, so it would be naive to assume it sips less gas. I think claims of 25+ mpg on highway for an AWD RX400h is a b.s. unless you drive less than 40 mph. In the city- quite possible.

oldcajun

The electric motors do not completely shutdown at 40 mph, they are still available for a little added acceleration above that. At high speed cruise, the air conditioner compressor and power steering pump are not engine driven, but are electrically powered so they draw no power from the engine. The CVT is more effecient than the 5 speed. These are some of the reasons the RX400 gets better highway gas mileage. There is obviously not as big a difference as in town, but it is a little better.
Steve

Kostyan

that may explain it. Does RX400h have any settings that allow the driver to adjust at which speed they want the gas engine to kick in?

jrobe

"hey nobody on here yet explained to me how do you guys get better highway mileage in RX400h when after 40 mph eletric motors shut down and the RX runs on pure gas engine. B y the way, it is a detuned 3.3L motor, so it would be naive to assume it sips less gas. I think claims of 25+ mpg on highway for an AWD RX400h is a b.s. unless you drive less than 40 mph. In the city- quite possible."


I get at least 27mpg on the highways and 29mpg+ in the city.

If you are really interested in how hybrid engines work, you need to do some research. You could start out at Lexus's own web site. Your questions show a complete misunderstanding of the mechanics of hybrids. Quite frankly, I doubt anyone here is going to take the time to educate you.

jditom

Our highway drive to Portland and back is 220 miles and we drive 65-70 mph. We get 26-28 mph depending on wind conditions. We have done this 10-12 times. Sorry to burst your bubble but it is not BS. Battery still charges and on slight decents engine goes off and elecrtic motors are running.
So yes I have seen e-motors running alone or adding to engine power even at 65 mph.

Kostyan

I get at least 27mpg on the highways and 29mpg+ in the city.

If you are really interested in how hybrid engines work, you need to do some research. You could start out at Lexus's own web site. Your questions show a complete misunderstanding of the mechanics of hybrids. Quite frankly, I doubt anyone here is going to take the time to educate you.[/QUOTE]


To JROBE: Please don't tell me what I need or not need to do ok? Just answer the question if you can, if not, please move on, and speak for yourself.

To all others:
According to edmunds.com RX400h' electric motors run up to 40 mph, and after that its running only on gas. Just as an example, Prius runs on pure electric only until 14 mph, after that its on pure gas.

I do not own a hybrid and have never test driven one, but what settings are there available to a driver to adjust the hybrid powertrain?

jrobe

"According to edmunds.com RX400h' electric motors run up to 40 mph, and after that its running only on gas. "


How many times do you have to be told that this is completely false? Again, 10 minutes on Lexus's web site would teach you otherwise but you wouldn't believe the information you learned there anyway.

You must be correct. The mileage people are getting with hybrid vehicles is all a lie. It is just a conspiracy to get you to buy the car.

NeoNz

are you serious dude? I can drive 65 in my rx and average 26-27 mpg. drive 70 and i see 25-26. drive 75 and i see 24-25.... and so on...

vulpasin

Not exactly

That expains things

Woow...I move on

Tony

LOL seriously, I just bought an 08 RX 400H and was suprised I am averaging 27 mpg in combo driving with 60% highway going 65-75mph and 40% city going 30-45mph. The hybrid system kicks butt and I am so glad to have it. I have not had to refuel for two and half weeks and coming up on my first fill up, where as before in my BMW 550 I was filling up weekly because it averaged 17mpg.

The EPA estimates were dead on. www.fueleconomy.gov just plug in your cars and compare side by side and custom set your driving style and gas prices. I figured I am saving $75-80.00 per month or a tank and a half per month. I also got a $250.00/year reduction from Farmers Insurance for driving a Hybrid so thats free gas money.

So at this rate the car will pay for its premium price in 4 years but you get better refinement in ride quality, more power and better sound proofing over the 350. If gas prices hit $6.00 to $7.00 per gallon which its predicted to do, the RX400H will pay for itself even sooner.

NeoNz

even with my 150+ lbs of stereo equipment and my giant ramming guard on the front of my RX ruining my aerodynamics, along with my 20" wheels and high-perf tires that aren't low-rolling-resistance, i still manage to average 24 mpg while driving 75 mph on the highway! all on 87 octane! gotta love the RX. I saw a bit of a drop after the wheels and stereo stuff and ramming guard but still well worth the price since im still able to run with a cayenne type S or range rover supercharged while they get 12-14 mpg im getting 24 highway and 27 around town!!