You are here: Forums Hybrid Vehicles Lexus RX 400h Lexus RX 400h

Lexus RX 400h

2334 messages,  Last post on Oct 11, 2009 at 10:42 AM

You are in the Lexus RX 400h Forum. Your Host is pf_flyer

What is this discussion about? Lexus RX 400h, Hybrid Cars

Messages Page 5 of 234 1 2 3 4 5 6 7 8 ... 234 Prev Next Last

Go To Msg # Search This Discussion

#41 of 2334 question about EPA mpg by ceric Feb 14, 2004 (1:44 am)
Imagine this... Do you think when EPA test highway MPG, they make sure th battery is bone-dry from previous runs (whatever they were) so that there is no "cheating"?   As an engineering professional, I am having a hard time believing 400h would get better highway MPG (claimed 31mpg) than standard 330's 26mpg. Just explain to me where the extra energy efficiency comes from when cruising on a 400 miles stretch of highway 5 from SF to LA? (remind you that there is very minimum braking)   If you know how EPA test MPG, you would smile. The numbers are inflated for hybrids. For regular vehicles, they are good for comparison only.   That said, I am very interested in 400h. It is one of the few vehicles I am considering to replace my '98 BMW 540iA.
#42 of 2334 by mytythor Feb 14, 2004 (8:58 am)
My 2001 RX came fully loaded and had an MSRP of just under $42K-bought it for $37.5K. I don't have a problem with an MSRP a bit higher than that, but $50K pushes my price point. I've owned many luxury cars in my life including Mercedes so you can figure my income bracket can handle it. We just set a limit as to how much we wish to spend on a car.
#43 of 2334 Re: question about EPA mpg by usbseawolf2000 Feb 14, 2004 (5:18 pm)
> Do you think when EPA test highway MPG, they make sure th battery is bone-dry from previous runs (whatever they were) so that there is no "cheating"?   HSD has minimum threshold (I believe 30%)for the battery capacity. When the battery hits below that, it'll recharge from the ICE. One of the concept of HSD is to store energy when the most appropriate and use it when the most beneficiary. Your suggestion is the situation HSD is designed to avoid. Draining the battery before EPA test would be cheating out of HSD.   > As an engineering professional, I am having a hard time believing 400h would get better highway MPG (claimed 31mpg) than standard 330's 26mpg. Just explain to me where the extra energy efficiency comes from when cruising on a 400 miles stretch of highway 5 from SF to LA?   To appreciate HSD efficiency, you'll need to understand sources of inefficiency in the traditional cars. Graham Davies explained on his site very well. http://home.earthlink.net/~graham1/MyToyotaPrius/Understanding/In- ternalCombustion.htm
#45 of 2334 by mytythor Feb 14, 2004 (7:13 pm)
If all the improvement in highway mileage is only 5mpg, then it will take forever to recoup the premium paid for the 400h over a standard RX 330.There just isn't enough data and pricing info yet to make an intelligent decision on the 400h
#46 of 2334 by usbseawolf2000 Feb 14, 2004 (8:40 pm)
> If all the improvement in highway mileage is only 5mpg   If your main usage is highway, SUV might not be the best suitable vehicle for you. Just a statement, not a suggestion.   RX330 FWD: 20 mpg / 26 mpg RX400h FWD: 36 mpg / 31 mpg 400h has combined millage of 33.5 mpg. 10.5 mpg more than RX330   RX330 AWD: 18 mpg / 24 mpg RX400h 4WD-i: 36+mpg / 31+mpg The 400h four wheel drive version is suppose to be even more efficient than 400h FWD version due to ability to recapture more energy from regenerate braking.   The idea was to improve fuel economy by 50% and translate the other 50% to performance. The result is the extra 40 hp, super ultra clean emission, and other benefits I posted previously.
#47 of 2334 usbseawolf2000 by ceric Feb 15, 2004 (4:41 pm)
Thanks for your info. I am afraid that your post would be removed soon due to violation of policy. Basically, the site talks about a different engine tuning is used since ICE (internal combusion engine) is no longer the only driving force. Efficiency can be optimized at near peak level. If the ICE used on 400h is different than the one on 330, then my question is answered. However, that was not what I have read. We will see. Thanks anyway.
#48 of 2334 Other than MPG and power by igiban Feb 16, 2004 (3:49 pm)
Would the RX400h offer less noisy ride than RX330. I test-drove a 330 just the other day and found the engine 'roar' during acceleration and tranny not all that smooth. I believe it's talked about on RX330 boards. I am wondering can we expect 400h to be quieter and smoother. That'd make $4K extra worth it to some.
#49 of 2334 This is great! by n2_itive Feb 16, 2004 (5:43 pm)
I was just telling my mother how great it would be if the 330 was a hybrid, just my luck... today I'm told that it will be. Not all Americans are gas guzzlers.
#50 of 2334 ecric by usbseawolf2000 Feb 16, 2004 (6:19 pm)
> Just explain to me where the extra energy efficiency comes from when cruising on a 400 miles stretch of highway 5 from SF to LA?   The same reason I4 Camry Auto gets 23 mpg / 32 mpg vs. V6 Camry Auto gets 21 mpg / 29 mpg. Lexus RX 400h will have similar engine as RX330. Instead of RX330 Otto cycle, 400h will use Akinson cycle. This fundamental change in engine cycle gives RX 400h better fuel economy (even highway). Akinson cycle enables the engine to be tuned closer to the "sweet" spot; resulting in higher efficiency. Akinson cycle has disadvantages as well but electric motor complements its shortcomings.   You can think of HSD as a married couple rather than a single person. Husband makes up for the wife's weakness and vice versa. It is the harmony between the two that gives overall higher efficiency. Regenerative braking and others are also responsible.   Dennis

Messages Page 5 of 234 1 2 3 4 5 6 7 8 ... 234 Prev Next Last

Go To Msg # Search This Discussion

You are here: Forums Hybrid Vehicles Lexus RX 400h Lexus RX 400h