Does anyone know if this is true and if so what does this battery power and what causes the drain when the vehicle is off?
I haven't compared the specs to my Camry battery, but the 12-volt battery in my RX400h looks like a regular sized car battery.
My manual set says "For parking longer than 30 days, charging of the 12-volt battery may be required." The high voltage battery is disconnected when the car is off so anything that runs then is using the 12-volt battery. For instance, internal lights when the doors are open, the receiver that listens for you key signal, the power door locks and rear door opener, etc. The manual does suggest that if you return to the car after parking for two weeks or longer, you turn start it and get the ready light on before you use the power rear door.
It also says that you should drive at least once every several months for at least 30 minutes or 10 miles to keep the hybrid battery in good condition. Since, that is disconnected when the car is off, they must just be worried about leakage there.
There is always battery drain when a car is sitting....whether it be a hybrid or not...
If you take whatever you are driving and sit it in the cold for a month without starting it, there's a good chance it won't start when you turn that key...I guess it would depend on how new your battery is...
The hybrid is sensitive to this as well....
As far as the automatic back liftgate...that drains a lot of energy...so, it makes sense not to use it if the battery is already drained a little for sitting for some time...
I think the precautions make sense....I'm also sure that if you let the car sit for 30 days in the summer as opposed to in the winter, you'd get a different result! As far as driving, the car definitely does better the more you drive it...short trips do not get great milieage as the gas motor is working for the first few minutes you turn on the car...to charge the battery...
Good suggestion - I'll ask my dealer to let me drive their demo 400h again this week just to compare handling. At this point, I have to keep my left hand on the wheel at all times just to avoid building up fatigue in my right wrist. This isn't my first SUV, but I don't remember having to work so hard to steer before and it doesn't feel like the 330 loaners they gave me at all.
The power stearing in the RX400h is electrical vs hydraulic.
There will be some significant differences in the "feel".
Hydraulics will not allow as much "push-back", feedback, to the steering wheel from rough road surfaces, roadbed sloping, or objects. And yes, the electrics will therefore require more driver attentiveness and hand pressure to maintain a good "track".
If Lexus even uses differential braking to prevent wheelspin or slip on FWD vehicles, or front torque biased AWD such as the RX400h certainly is, then even lower brake modulation levels will be used on the hybrid because of the electric power stearing.
I've noticed that some cars with electric steering differ. I had a Mini Cooper that had electric steering and it tracked superbly. I think most new vehicles will have this method of steering within the next few years.
Will servicing the Lexus RX 400h require any special talents? I have a mechanic that has been servicing my cars for the last 20 years and wonder if this car will require special knowledge. I plan to pick up my RX 400h in about a month and was told by the dealer that my car is on the boat about to be docked. That sounds a lot like "the check is in the mail". In any case I am thinking about leasing rather than purchasing. Does anyone have any idea what a 36 month lease without a deposit which allows for 15,000 per year might cost. The only option I took was the heated seats.
The roads in our neighborhood are fairly crowned and I don't find it takes any more attentiveness or work to steer the RX400H than my Camry. We are now on the third tank and thanks to the late rains, we have had plenty of time to try it out on wet roads. The handling on ours is great. From what the original poster describes, it sounds like he has a defect or damage from mishandling by the techs at his dealer.
Well, maybe there's hope for my car if yours behaves the way you describe it. My dealer has already replaced the steering controller, so I'm not sure what else they can do. I'll retest drive the demo to see if it feels better than mine, and if so, perhaps they can figure something out. I wonder if the steering drive motor is ok, and if there is any adjustment available to the amount of boost with electric steering...
If there is no opportunity to recover inertial energy during braking and/or coastdown then the hybrid concept is actually a huge detriment to fuel economy.
If there is no opportunity to recover inertial energy during braking and/or coastdown then the hybrid concept is actually a huge detriment to fuel economy.
I'm not so sure. I think you have to consider it on a performance-equivalent basis. Lexus likes to say you're getting V8 type performance from a V6 engine, and they have a point imho, so the more appropriate comparison is to the fuel economy of an equivalent-performance vehicle...maybe a V8. Even without the inertial energy capture, with a 400h you're getting the performance benefits of an extra cylinder or two without paying for the gasoline for that extra cylinder or two when the hp/torque isn't needed.
Ahh, success at last! I took out the dealer's demo 400h out for a test drive this morning and noticed a considerable difference in handling compared to my own new car. The alignment wizard at my dealer was actually on duty today, and he made an adjustment. Apparently Lexus allows up to +/- 0.75 degrees of range in the steering alignment, and mine was set on dead center. So, he reset it for 0.5 degrees to the left which fixed the problem and it's still well within the recommended range. Half a degree may not sound like much, but now my 400h feels like a different car. The steering is still a bit heavy compared to some other cars, but now there's no tracking problem. I guess they don't all come off the line exactly the same way, do they?
But during highway cruise just how often do you need V8 level performance?
I just drove my 2001 AWD RX300 from Seattle eastside to and from Lewistown MT. I90 to Garrison, over the continental divide to Helena, I15 to great Falls, then on to Lewistown via a two lane road, mostly. ~1600 miles.
At no time did I feel the V6 was lugging on the various (wet, no snow/ice) mountain passes nor did I wont for more HP when passing. MT drivers are NOT slouches and the RX came up to passing speed as quickly as I could have desired.
Most of the drive (except in WA) was done with the cruise set above 75MPH so passing generally meant exceeding 90MPH. Averaged above 20MPG overall.
I'd be curious to know if the RX400h can do as well in MPG, obviously not enough need for the higher level of performance, rarely WOT.
From what people are posting it would appear that they would have gotten around 25 MPG on the same trip in an RH. Certainly would take some time to justify the 9k additional price!
Yes, you are correct that it would be very difficult to make your money back on just fuel savings. BUT you keep forgetting that you are not just giving that $9k away either. You should make at least have of it back on resale and depending on where you live around $750+ on tax savings. That, along with fewer trips to the pump, less money to the oil companies, less emisions with more power, should make it at least breakeven for most people.
I'd do it for that reason, but other won't. If someone even balks at the prospect of spending the add'l money, they should not consider it as they'll constantly be second guessing themselves. I also hear some states do not charge sales tax, which makes the spread even less.
Unfortunately I live in California where there is no such sales tax break. But I look on the bright side, gas is so expensive here that it won't take me that long to breakeven :shades: !
that govern how much energy it takes to move a mass such as my RX300 or the RX400h 1600 miles at 75+ MPH.
If the RX400h, weighing more than my RX300, actually does 25% better than my 2001 RX then Toyota should share their secrets with the rest of the manufacturers to help us reduce our dependance on fossil fuels altogether.
... of the EPA that the highway mileage of the RX400 is ~12.5% better than that of the RX330 (27 vs. 24 in AWD).
Apparently, something useful goes on with the hybrid on the highway despite what you keep wrongly insisting. This is especially salient because the 400 weighs more. So clearly, it is that much more efficient than the MPG advantage would indicate.
I just heard on the news that some Prius owners have had a stalling problem. Toyota is investigating, but has not announced a recall. Have any of you 400h owners experienced this problem? :confuse:
Just curious, but I am getting 27+ on the highway, I wonder how many AWD 330 owners are getting the advertised 24mpg? Also, I do see the electric motors engaged on the freeway, not just the engine, so I'm sure they are helping with the increased mileage.
Or maybe if I drove at the speed required to create road rage in all those behind me waiting for an opportunity to pass.
The MT trip was without the A/C enabled. I have the c-best option set to disabled it in all modes unless I decide to turn it on manually. I only use it if the OAT is above 65F or if the radiant heating effects require it. Wasn't used much on the MT trip.
No mystery here, I think - the engine's tuned more for fuel economy than performance on the hybrid, which they can get away with because they have the electric system to make up the difference.
25% advantage in fuel economy just from engine (de-)tuning...
NOT!
If it were that simple, or REAL, then all manufacturers would be using it given the current gas prices. In highway cruise there is no opportunity to recharge the batteries for "free". So when the batteries are used, and they are, in highway cruise the only recharge method is via the ICE. It is simply not possible to increase fuel economy by using the ICE to charge batteries and then using that charge to add boost to the engine when/if needed.
Were it equipped with a smaller lighter weight engine with fewer frictional and pumping losses than the same engine, virtually, as my 01 RX300 then maybe I could be a believer. As it is the V6 in the RX400h MUST produce the same level of energy, if not more, that my 01 does at equivalent highway cruise speeds. Obviously if that level is achieved via the batteries then the high loss path using the ICE to recharge the batteries will be detrimental to fuel economy.
That's why, basically, the Prius has lower highway cruise fuel economy than a comparable and comparably equipped non-hybrid vehicle.
Our 2003 Prius' fuel economy over ~15,000 miles is ~42MPG, both according to the OBC and hand calculation, ~400 gallons. The 2005 Prius weights 2890lbs, a drag coefficient of .26 and ratings of 60/51/55. The Toyota Echo weighs 2055lbs and is rated at 35/42.
The mileage accrued on our 2003 Prius is principally city, the only highway mileage was a trip to Portland and return, ~300 miles, and the MPG was significantly lower than the 42MPG overall average. I'm sure that, like the Prius, the quoted highway mileage for the Toyota Echo is unrealistic, but even if we assume it's really ~35MPG hwy that certainly very close to the Prius for highway driving.
Hybrids have their place, ultra-low emissions, stellar city MPG, but absolutely no advantage for highway cruise.
quote wwest-"That's why, basically, the Prius has lower highway cruise fuel economy than a comparable and comparably equipped non-hybrid vehicle."-end quote
"Hybrids have their place, ultra-low emissions, stellar city MPG, but absolutely no advantage for highway cruise".
If there is absolutely no advantage for highway cruise, then how is it possible that folks are indeed getting the EPA estimate of 27 mpg on the highway with the RX400? This is a vehicle that weighs more than the RX330. I don't see how you can say there is no advatange. Something must be causing it to get better gas mileage than the 330 on the highway.
Obviously, the RX400h, despite weighing more, gets better highway mileage than the RX330.
How does this happen if it "simply isn't possible"?
It is possible. I'm not an engineer, but perhaps it's the ability to run the engine at a more constant speed more of the time irrespective of the vicissitude of traffic? Perhaps it's also detuned a bit? Whatever the case, it actually is happening. So it, well, must be possible.
Explain why my friend's Prius averages 40 MPG at sustained 80 MPH. I don't see an Echo doing that and it is a lighter car with the same engine (non atkins).
I agree....it is possible. I'm sure the transmission helps, but also the electric motors do kick in on the freeway as well. Anytime more power is needed they will come on to help supplement the engine, I've also seen them go on during slight declines, where it is not enough to just idle, but when a little gas...opps, I mean power is needed.
In highway cruise where do the batteries get the re-charge so the electric motors can continue to "kick in"??
ONLY from the ICE.
I'm not from Missouri but some one will have to show me an RX400h getting better hwy fuel economy that a FWD RX300 or even an RX330 before I will believe it.
Prius averaging 40MPG at a sustained 80MPH.....
That must be one long downhill run or someone's nose is growing longer by the day. Not even Toyota is willing to support that claim.
I used to own a 99RX and over the life of the vehicle I averaged close to 19 MPG. I see that people with mixed driving are averaging 25. That's a decent improvement.
Additionally Lexus, LEXUS, rates the RX400h at 27MPG HWY vs 25MPG HWY for the RX330.
Well, you are the one who said 24 mpg never for your RX 330 on the highway. By the way, it is 25 mpg for FWD RX330, 24 mpg for AWD RX330.
I am consistantly gettiing 26-27 mpg with my RX400h on the highway at 65 mph.
There are a number of ways that the hybrid helps on the highway - not as much advantage as city driving, but still something.
The freeway around here isn't entirely flat. When I go downhill, there is some battery charging. When I go up hill, the electric kicks in to help. The same happens when there are fluctuations in speed due to the other traffic.
With the engine running in a narrower range, they can tune it to optimize efficiency in that range while the RX330 engine has to work well over a wider range.
There is the different transmission and that during cruising on the highway the RX400h is driving like the FWD rather than the AWD.
They also did some tweaks on the RX400 to improve drag - underbody and in the wheel wells. That was partly to offset the additional drag from the additional air vents in the front but perhaps there was some improvement left over.
We weren't counting on better highway mileage when we bought the car since our daily driving is at least 70% city, but I've been happily surprised about how close we come to the EPA highway number which is suppose to reflect 60 mph driving.
The EPA has determined under very precise testing conditions that the AWD 400h uses 12.5% less fuel than the AWD 330 over an identical highway cycle. That is fact. The only argument is the relevance of that test cycle to real world driving. The 400h clearly has some technology that benefits highway MPG, at least for the EPA cycle.
On the highway, the ECVT allows the engine to run at a very low, and therefor very efficient, engine speed. Lower engine speeds are more efficient because friction is lower at lower speeds (and engine life is improved), and because in throttled engines, throttling losses are lower at higher power settings measured as a percent of full load. At lower engine RPMs, the power necessary for highway cruise is a higher percentage of the engines full load at that engine speed.
Part of the reason that you see the electric motor in use on the highway is that MG1 (motor generator 1) absorbs energy from the power split device in order to control the speed of the ICE (at low engine speeds and high road speeds, MG1 is turning backwards). In the Prius, the torque split of the ICE (internal combustion engine) is 72% to the wheels and 28% to MG1. The energy generated by MG1 charges the batteries, or goes directly to the wheels through MG2, a second electric motor, also used to start the engine, which is coupled to the output of the ICE.
The computer is always trying to keep the ICE in a narrow band of the most efficient speeds and loads, and that helps MPG in any kind of driving.
The other reason you see the electric motor in use on the highway is that you do use the brakes on the highway or go down hill now and then, and the battery will add power to the wheels to use up that recovered energy.
The power split device is a very complex piece of engineering, here are two excellent descriptions of various aspects of the operation of the Prius PSD
There is not much out there on the 400h system. I will get an OBDII reader soon and begin to study the operation of the system. You can see and log all of the engine computer parameters on a PDA in the car through a port behind the dash. Engine speed, engine power, throttle position, and a host of others. I don't know if you can get access to the hybrid specific info.
I am getting slightly better than 27 mpg on highway driving on my 400h. I just traded in a 330 awd that only very rarely gave me 24 mpg. My blended mileage on the 330 was around 19.5. I am now avering 27.3 after 300 miles on the 400h.
Another question regarding extended warranties. What prices are being quoted? My dealer told me that they only get a $100 markup from Lexus on the warranty - obviously a fib. They also told me that if I kept the car for 7 years and did not use the warranty they would refund all the money. Anyone else here anything like this?
Please don't turn this discussion into a debate about hybrid gas mileage. We already have a discussion called Hybrid Gas Mileage: Good? Bad? As Expected? Let's try to focus on the Lexus RX 400h, and take the mileage debate elsewhere. Plenty of members are interested in the other features and ownership experiences with this vehicle.
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I was also offered the same, with the same issue if not used would be refunded. Price was about 2200, I still have not decided, have 30 d from date of purchase, a week ago, I keep cars about ten years and this is new technology. What are your thoughts?
I quite firmly believe that it is a practical impossibility to have conversations "here" about the RX400h hybrid system's fuel economy without some reference to other hybrid systems as context. I think we can all quite willingly conform to the spirit of your request and be sure and "mainstream" the conversations along the lines of the RX400h hybrid system, but it would be foolish not to occassionally use other hybrid systems as reference.
And as was stated, indicated, above, we need some leeway until more information of the actual workings of the RX400h becomes available.
But when the EPA says the FWD RX330 is rated at 25MPG I always discount their figures and I tend to not believe anyone saying they get those numbers. To many years of history that says their numbers are not real world and simply cannot be achieved by us ordinary citizens.
The EPA rates the AWD RX330 at 24, not 25. The hybrid -- which is AWD -- is 27.
And, again, this is integral to the 400h. Part of the rationale for buying one is about the payback period. This isn't like the Prius -- which has no "normal" counterpart. It's more like the Accord, and I don't see how one could talk about that either without referencing mileage relative to the RX330.
Regardless of whether the 24 or the 27 is achievable in the real world -- and some are indeed achieving 27 on the highway with the hybrid -- they show the relative difference in mileage between the two, wwest. So while none of us are stating that we can explain exactly what's going on, there is clearly an improvement.
would anyone give greater consideration to the value of the EPA numbers for the RX400h than the numbers for the RX330? We all know, or should know, that the EPA numbers ALWAYS falsely overstate the MPG actually attainable.
Personally I feel that the RX400h numbers will be even more over-stated due to the ability of the manufacturers to better understand the technology than the EPA and thereby be able to more readily FOOL the EPA.
Look at the Prius numbers, 60/51/55, as an example. Any Prius owners out there getting anything even close to those numbers, reliably?
Ours is an 03 model, but at 42MPG as an overall average for 95% city that's no where near the EPA "estimate", even for an 03.
I don't know about the EPA numbers always falsely overstating actual MPG numbers.
I have driven a LS400 about 700 miles roundtrip with speed set at about 75-77 on cruise control and gotten a bit over 28MPG. The EPA estimates for the LS400 are 19/25.
Comments
I haven't compared the specs to my Camry battery, but the 12-volt battery in my RX400h looks like a regular sized car battery.
My manual set says "For parking longer than 30 days, charging of the 12-volt battery may be required." The high voltage battery is disconnected when the car is off so anything that runs then is using the 12-volt battery. For instance, internal lights when the doors are open, the receiver that listens for you key signal, the power door locks and rear door opener, etc. The manual does suggest that if you return to the car after parking for two weeks or longer, you turn start it and get the ready light on before you use the power rear door.
It also says that you should drive at least once every several months for at least 30 minutes or 10 miles to keep the hybrid battery in good condition. Since, that is disconnected when the car is off, they must just be worried about leakage there.
If you take whatever you are driving and sit it in the cold for a month without starting it, there's a good chance it won't start when you turn that key...I guess it would depend on how new your battery is...
The hybrid is sensitive to this as well....
As far as the automatic back liftgate...that drains a lot of energy...so, it makes sense not to use it if the battery is already drained a little for sitting for some time...
I think the precautions make sense....I'm also sure that if you let the car sit for 30 days in the summer as opposed to in the winter, you'd get a different result! As far as driving, the car definitely does better the more you drive it...short trips do not get great milieage as the gas motor is working for the first few minutes you turn on the car...to charge the battery...
Headless
There will be some significant differences in the "feel".
Hydraulics will not allow as much "push-back", feedback, to the steering wheel from rough road surfaces, roadbed sloping, or objects. And yes, the electrics will therefore require more driver attentiveness and hand pressure to maintain a good "track".
If Lexus even uses differential braking to prevent wheelspin or slip on FWD vehicles, or front torque biased AWD such as the RX400h certainly is, then even lower brake modulation levels will be used on the hybrid because of the electric power stearing.
Shackman
My 400h is due to land in Portland on June 5th and I anticipate picking it up 7-10 days later. Can't wait to get some quality time behind the wheel.
If there is no opportunity to recover inertial energy during braking and/or coastdown then the hybrid concept is actually a huge detriment to fuel economy.
I'm not so sure. I think you have to consider it on a performance-equivalent basis. Lexus likes to say you're getting V8 type performance from a V6 engine, and they have a point imho, so the more appropriate comparison is to the fuel economy of an equivalent-performance vehicle...maybe a V8. Even without the inertial energy capture, with a 400h you're getting the performance benefits of an extra cylinder or two without paying for the gasoline for that extra cylinder or two when the hp/torque isn't needed.
I just drove my 2001 AWD RX300 from Seattle eastside to and from Lewistown MT. I90 to Garrison, over the continental divide to Helena, I15 to great Falls, then on to Lewistown via a two lane road, mostly. ~1600 miles.
At no time did I feel the V6 was lugging on the various (wet, no snow/ice) mountain passes nor did I wont for more HP when passing. MT drivers are NOT slouches and the RX came up to passing speed as quickly as I could have desired.
Most of the drive (except in WA) was done with the cruise set above 75MPH so passing generally meant exceeding 90MPH. Averaged above 20MPG overall.
I'd be curious to know if the RX400h can do as well in MPG, obviously not enough need for the higher level of performance, rarely WOT.
If the RX400h, weighing more than my RX300, actually does 25% better than my 2001 RX then Toyota should share their secrets with the rest of the manufacturers to help us reduce our dependance on fossil fuels altogether.
Apparently, something useful goes on with the hybrid on the highway despite what you keep wrongly insisting. This is especially salient because the 400 weighs more. So clearly, it is that much more efficient than the MPG advantage would indicate.
They did- they licenced the technology to Ford.
Or maybe if I drove at the speed required to create road rage in all those behind me waiting for an opportunity to pass.
The MT trip was without the A/C enabled. I have the c-best option set to disabled it in all modes unless I decide to turn it on manually. I only use it if the OAT is above 65F or if the radiant heating effects require it. Wasn't used much on the MT trip.
NOT!
If it were that simple, or REAL, then all manufacturers would be using it given the current gas prices. In highway cruise there is no opportunity to recharge the batteries for "free". So when the batteries are used, and they are, in highway cruise the only recharge method is via the ICE. It is simply not possible to increase fuel economy by using the ICE to charge batteries and then using that charge to add boost to the engine when/if needed.
Were it equipped with a smaller lighter weight engine with fewer frictional and pumping losses than the same engine, virtually, as my 01 RX300 then maybe I could be a believer. As it is the V6 in the RX400h MUST produce the same level of energy, if not more, that my 01 does at equivalent highway cruise speeds. Obviously if that level is achieved via the batteries then the high loss path using the ICE to recharge the batteries will be detrimental to fuel economy.
That's why, basically, the Prius has lower highway cruise fuel economy than a comparable and comparably equipped non-hybrid vehicle.
No free lunches.
The mileage accrued on our 2003 Prius is principally city, the only highway mileage was a trip to Portland and return, ~300 miles, and the MPG was significantly lower than the 42MPG overall average. I'm sure that, like the Prius, the quoted highway mileage for the Toyota Echo is unrealistic, but even if we assume it's really ~35MPG hwy that certainly very close to the Prius for highway driving.
Hybrids have their place, ultra-low emissions, stellar city MPG, but absolutely no advantage for highway cruise.
See my response in the Prius forum please !!!
If there is absolutely no advantage for highway cruise, then how is it possible that folks are indeed getting the EPA estimate of 27 mpg on the highway with the RX400? This is a vehicle that weighs more than the RX330. I don't see how you can say there is no advatange. Something must be causing it to get better gas mileage than the 330 on the highway.
Obviously, the RX400h, despite weighing more, gets better highway mileage than the RX330.
How does this happen if it "simply isn't possible"?
It is possible. I'm not an engineer, but perhaps it's the ability to run the engine at a more constant speed more of the time irrespective of the vicissitude of traffic? Perhaps it's also detuned a bit? Whatever the case, it actually is happening. So it, well, must be possible.
In highway cruise where do the batteries get the re-charge so the electric motors can continue to "kick in"??
ONLY from the ICE.
I'm not from Missouri but some one will have to show me an RX400h getting better hwy fuel economy that a FWD RX300 or even an RX330 before I will believe it.
Prius averaging 40MPG at a sustained 80MPH.....
That must be one long downhill run or someone's nose is growing longer by the day. Not even Toyota is willing to support that claim.
See:
http://www.lexus.com/home/faqs/hybrid.html
Additionally Lexus, LEXUS, rates the RX400h at 27MPG HWY vs 25MPG HWY for the RX330. Not even a 10% improvement even if you believe EPA numbers.
Well, you are the one who said 24 mpg never for your RX 330 on the highway. By the way, it is 25 mpg for FWD RX330, 24 mpg for AWD RX330.
I am consistantly gettiing 26-27 mpg with my RX400h on the highway at 65 mph.
There are a number of ways that the hybrid helps on the highway - not as much advantage as city driving, but still something.
The freeway around here isn't entirely flat. When I go downhill, there is some battery charging. When I go up hill, the electric kicks in to help. The same happens when there are fluctuations in speed due to the other traffic.
With the engine running in a narrower range, they can tune it to optimize efficiency in that range while the RX330 engine has to work well over a wider range.
There is the different transmission and that during cruising on the highway the RX400h is driving like the FWD rather than the AWD.
They also did some tweaks on the RX400 to improve drag - underbody and in the wheel wells. That was partly to offset the additional drag from the additional air vents in the front but perhaps there was some improvement left over.
We weren't counting on better highway mileage when we bought the car since our daily driving is at least 70% city, but I've been happily surprised about how close we come to the EPA highway number which is suppose to reflect 60 mph driving.
On the highway, the ECVT allows the engine to run at a very low, and therefor very efficient, engine speed. Lower engine speeds are more efficient because friction is lower at lower speeds (and engine life is improved), and because in throttled engines, throttling losses are lower at higher power settings measured as a percent of full load. At lower engine RPMs, the power necessary for highway cruise is a higher percentage of the engines full load at that engine speed.
Part of the reason that you see the electric motor in use on the highway is that MG1 (motor generator 1) absorbs energy from the power split device in order to control the speed of the ICE (at low engine speeds and high road speeds, MG1 is turning backwards). In the Prius, the torque split of the ICE (internal combustion engine) is 72% to the wheels and 28% to MG1. The energy generated by MG1 charges the batteries, or goes directly to the wheels through MG2, a second electric motor, also used to start the engine, which is coupled to the output of the ICE.
The computer is always trying to keep the ICE in a narrow band of the most efficient speeds and loads, and that helps MPG in any kind of driving.
The other reason you see the electric motor in use on the highway is that you do use the brakes on the highway or go down hill now and then, and the battery will add power to the wheels to use up that recovered energy.
The power split device is a very complex piece of engineering, here are two excellent descriptions of various aspects of the operation of the Prius PSD
http://home.earthlink.net/~graham1/MyToyotaPrius/Understanding/PowerSplitDevice.htm
http://home.earthlink.net/~graham1/MyToyotaPrius/Understanding/ContinuouslyVariableTransmi- ssion.htm
There is not much out there on the 400h system. I will get an OBDII reader soon and begin to study the operation of the system. You can see and log all of the engine computer parameters on a PDA in the car through a port behind the dash. Engine speed, engine power, throttle position, and a host of others. I don't know if you can get access to the hybrid specific info.
Another question regarding extended warranties. What prices are being quoted? My dealer told me that they only get a $100 markup from Lexus on the warranty - obviously a fib. They also told me that if I kept the car for 7 years and did not use the warranty they would refund all the money. Anyone else here anything like this?
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Price was about 2200, I still have not decided, have 30 d from date of purchase, a week ago,
I keep cars about ten years and this is new technology. What are your thoughts?
And as was stated, indicated, above, we need some leeway until more information of the actual workings of the RX400h becomes available.
And, again, this is integral to the 400h. Part of the rationale for buying one is about the payback period. This isn't like the Prius -- which has no "normal" counterpart. It's more like the Accord, and I don't see how one could talk about that either without referencing mileage relative to the RX330.
Regardless of whether the 24 or the 27 is achievable in the real world -- and some are indeed achieving 27 on the highway with the hybrid -- they show the relative difference in mileage between the two, wwest. So while none of us are stating that we can explain exactly what's going on, there is clearly an improvement.
Personally I feel that the RX400h numbers will be even more over-stated due to the ability of the manufacturers to better understand the technology than the EPA and thereby be able to more readily FOOL the EPA.
Look at the Prius numbers, 60/51/55, as an example. Any Prius owners out there getting anything even close to those numbers, reliably?
Ours is an 03 model, but at 42MPG as an overall average for 95% city that's no where near the EPA "estimate", even for an 03.
I have driven a LS400 about 700 miles roundtrip with speed set at about 75-77 on cruise control and gotten a bit over 28MPG. The EPA estimates for the LS400 are 19/25.