- #2032 of 2334
-
pricing
by katzjamr
-
Oct 08, 2005 (11:18 am)
-
|
|
Replying to: mkkid (Oct 08, 2005 5:39 am)
$70 is the going rate in seattle for an oil and filter change using Castrol synthetic blend, at the Lexus dealer, and would include a tire rotation and a traction battery load check. I have no idea what is included in your $800 'maintenance' service. As much as you trust your local service guy i would make sure you dont do anyting to void the vehicle warranty. We are basically trusting that the HSD and the other Toyota parts are going to last, and the toyota hybrid, and bumper to bumper warranties could come in handy. Service at a dealership documents what was done in their national computer system. Many Lexus owners go to Toyota dealerships for service as their rates may be cheaper. They have mechanics that are hybrid trained to work on the Highlander and will be familiar with the 400h system. Our local Toyota dealerships frequently have oil change specials. Out of warranty period i would be less married to a dealership as there are much better repair values to be found at a service center you trust.
|
- #2033 of 2334
-
Strange/Weird...
by wwest
-
Oct 12, 2005 (3:45 pm)
-
|
The maximum output from the hybrid battery is stated (by Lexus) as being 45KW. The front A/C motor is capable of 167HP, 123KW, and the rear 68HP, 50KW.
The total, net, for the ICE & electrics is stated as only 268HP.
Why would they put a 167HP(123KW) AC motor in the RX400h if the most it can ever produce is ~60HP(45KW)?
Is there a reasonable/logical explanation?
|
- #2034 of 2334
-
Re: Strange/Weird... [wwest]
by rx400hfan
-
Oct 13, 2005 (5:10 am)
-
|
|
Replying to: wwest (Oct 12, 2005 3:45 pm)
It is not really strange if you look at the planetary gear cvt as the power split device that it is. You will see that for the ICE to get any power to the road a percentage of power will be delivered to MG1 in generating electricity. This generated electricity can be directed directly to MG2 in addition to the 45KW from the battery to produce maximum power.
|
- #2035 of 2334
-
Re: Strange/Weird... [rx400hfan]
by wwest
-
Oct 13, 2005 (9:09 am)
-
|
|
Replying to: rx400hfan (Oct 13, 2005 5:10 am)
But that still doesn't explain why MG1 is rated so high, far above anything that can ever be produced.
|
- #2036 of 2334
-
Re: Strange/Weird... [wwest]
by rx400hfan
-
Oct 13, 2005 (10:32 am)
-
|
|
Replying to: wwest (Oct 13, 2005 9:09 am)
In all of the technical presentations of the HSD I have seen, MG1 is the Motor/Generator connected to the sun gear of the PSD and functions as a generator most of the time that the ICE is producing power. MG2 is the larger Motor/Generator connected to the ring gear of the PSD and through reductions gears to the front axle. Therefore MG2 in this example is the motor for which we are given the HP rating. Since the ICE is attached to the planetary gear carrier, anytime it is producing power a fixed percentage of torque will be provided to MG1 (Primarily a generator when the ICE is running) with the remaining percentage of torque applied to the front axle in parallel with MG2. I am not familiar with the gear ratios of the PSD used in the Lexus but the ratio was 28% to MG1 vs. 72% to MG2/Drivetrain on the Prius. Here is where it get rather complicated. Power is not a function of only torque but of torque & RPM so when we stomp the accelorator at low speed the engine power & rpm rise dramatically yet our road speed has not yet risen nearly as much. Therefore even though the axle is receiving 72% of the torque from the ICE it is receiving a much lower percentage of the power output of the engine. The only way the engine rpm & power can rise is for MG1 to spin up to a very high rpm and absorb all the remaing output power of the ICE by acting as a generator. So at low speed/high throttle a large portion of the power output of the ICE is in the form of electrical power from MG1, all this power is added to the power coming from the battary and fed into the large MG2 Traction motor.
|
- #2037 of 2334
-
But....
by wwest
-
Oct 13, 2005 (12:27 pm)
-
|
Lexus states that the TOTAL, net HP is 268.....
That's basically 208 from the ICE and 60 (45KW) from the "hybrid" aspect.
Is it possible that Lexus initially planned to have a ~140KW hybrid battery set and then things went awry for some reason before it entered production?
That would also account for the "400" in RX400h.
208HP ICE, 192HP (140KW) electrics.
And remember, keep in mind, the city/hwy MPG being reported by owners is completely out of whack, opposite, with the EPA estimates and what is being reported for the Prius.
Would a more robust battery pack had produced a more appropreate city MPG?
|
- #2038 of 2334
-
Re: But.... [wwest]
by rx400hfan
-
Oct 13, 2005 (1:23 pm)
-
|
|
Replying to: wwest (Oct 13, 2005 12:27 pm)
No they didn't plan anything other than what it is. The 400 in RX400h stands for power equal to a 4.0 liter engine just like RX330 = 3.3 liter engine. You missed the whole point of the explanation above in that at low road speeds you need 192HP electrics to be able to use the 208HP of the ICE since most of the power takes the path of electric from MG1 to MG2 otherwise at low speed you would have to limit the power output of the ICE to a small fraction of what it has. This would be the equivalent of eliminating any lower gears on a regular vehicle.
|
- #2039 of 2334
-
Okay....
by wwest
-
Oct 13, 2005 (2:09 pm)
-
|
When I am WOT and the ICE is producing 208HP are you saying half of that drives the generator and then from the generator that half drives MG2...
CVT....
If I jack up the rear end of a RWD vehicle with just a simple open diff'l, put it gear with the engine running and hold one wheel stationary with just my little pinky...
If you think of the opposite wheel, now spinning rapidly, as MG1, that's the way I thought the CVT in the Prius, RXh and HH worked. Virtually no energy needed at MG1 to prevent the ICE from conveying energy to the roadbed via the opposite end of the diff'l if you want to remain stopped.
So how do I overcome the "traction" force of my pinky?? I stop allowing MG1 to "freewheel", in other words I supply it with enough energy to turn it AGAINST the motive force of the engine. Remember that MG1 has a serious mechanical advantage over the ICE via the planetary gearset, so it doesn't take much energy, relatively.
I assume the above moves the vehicle in reverse and if I apply AC power to MG1 to AID in supplying motive force the vehicle goes forward.
But yes, assuming I am not requiring WOT performance, the ICE torque can be used to to recharge the batteries.
|
- #2040 of 2334
-
Re: But.... [rx400hfan]
by wwest
-
Oct 13, 2005 (2:13 pm)
-
|
|
Replying to: rx400hfan (Oct 13, 2005 1:23 pm)
Sorry.........
Are you confusing "low speed" with constant speed?
At a constant speed, even uphill or towing, very little of the ICE capability is required for forward motion, So clearly, it can then be used to recharge the batteries.
But if I am accelerating rapidly....
|
- #2041 of 2334
-
Re: Okay.... [wwest]
by rx400hfan
-
Oct 13, 2005 (6:06 pm)
-
|
|
Replying to: wwest (Oct 13, 2005 2:09 pm)
The more accurate analogy is for your RWD car to have one side jacked up on a stand with castors and have it in gear and have someone step on the throttle. The car is not going to move but the jacked up wheel will spin madly. The only way to get the wheel still on the ground to move the car is for something to hold the spinning wheel back. I do know with absolute certainty that if you grab that wheel to slow it down to cause the other one to move the car, that it will take you apart before you can hold it back enough to get the car moving.
You are correct that MG1 will be freewheeling when the ICE is running and the Lexus is stationary, but when you push the accelerator MG1 does not hold back by taking power from the battery it holds back by being a generator and providing the generated power to MG2. Due to the laws of physics while the vehicle is still stationary 100% of the power output of the engine (less slight gear losses) will be through MG1 acting as a generator. This power is directed into MG2 in addition to the battery power. As the vehicle speed increases more and more of the ICE power goes directly to the wheels via the ring gear of the PSD. Since the ring gear of the PSD and MG2 are tied directly together and then to the drive axle their speed is directly tied to vehicle speed. At the point where ICE rpm = MG2 RPM 28% of the power from the ICE will be generating electric through MG1 and 72% will be applied to the drive train.
|
![[F]](http://a332.g.akamai.net/f/332/936/12h/www.edmunds.com/media/townhall/webxicons/site.gif){kind=small}
Forums
Hybrid Vehicles 
