Toyota Highlander Hybrid Driving Tips & Tricks

tallmand · January 2006

I am new to this discussion list. I am discouraged with the 22.6 mph I have been getting on my 2006 HH. Living in South Dakota, and having owned a Prius, I expected somewhat lower mph due to the cold. In these days of Global Warming, however, temperatures have been in the mid-20s F, and often above freezing. Only twice have I achieved 26 mph, both during long road trips. Any suggestions?

upstateny5 · January 2006

I have religiously kept track of all tank fillups / mpgs. My regular home is upstate NY where mpgs started to drop with the cold temps and I ended up around 22 before leaving for Florida. I am now around high 25 - 26 and hope to see further improvements. I have found that so much depends on warming the car up - she doesn't like short trips even in warm temps. If I combine several short trips then they get progressively better.

I do practice p&g where possible and that helps. I also did check with the local dealer here and confirmed that there are no software updates.

Sorry this isn't more helpful - my car is listed on the hybrid database site - Phantum (car name). http://www.greenhybrid.com/compare/mileage/

cdptrap · January 2006

Welcome!

Don't give up yet, try a few more tricks to see if the mileage improves.
It will never get the Prius mpg numbers of 45-50 mpg, 26-28 mpg is definitely possible. Traffic and terrain will impact the mileage.

Try the following and many posters here have lots of experience to offer too.
1. Tire pressure - we use 36 psi. Some posters use 38 psi but that gives a hard ride.

2. Use of A/C + HEATER will bring down MPG but when it gets to 20-F, one has little choice.

3. Use the Prius Pause-and-Glide approach. Bring the car up to speed, take foot off gas, then set CRUISE at desired speed. The HH is good at deciding when to use the electric motor all by itself when CRUISE is ON.

4. If possible, pick flatter roads and roads with few stops, few turns and no overpasses.
This can be tough but will improve mileage.

5. Anticipate stops and coast a lot.

6. Easy smooth acceleration. We try to accelerate from a traffic light at a rate that still gives 10-MPG. The on-board MPG bar-indicator below the speedometer helps us monitor our acceleration rate. We do this to get up to 25-MPH. It seems "fast" enough for drivers behind us, no trouble yet.

7. If we have to accelerate past 25-MPH and the CRUISE speed had been set before, we just get up to 25-MPH smoothly and then activate the CRUISE-RESUME to let it accelerate the rest of the way. The car knows to accelerate at a rate that returns 10-MPG.

8. Short <=3-mile trips with many stops requiring complete engine OFF will kill mileage. We did this the first 2 months and had to change our approach.

Another poster recently had the same concern you have and she was quite upset. After finding information on P&G and trying different driving techniques, she posted marked improvement in mpg. See post #2388. There is also another owner who could not get beyond 24-mpg, he/she posts here periodically but I forgot his ID.

Let us know if any of these techinques help you at all.

Good luck!

worsthhdriver · January 2006

Well, I must be the worst HH driver ever. On a recent tank I got a whopping 15.4 mpg!!! I've been really careful lately and got up to 19.5 mpg on a recent tank. But I still haven't gotten more than 265 miles on a tank. The kicker is that when I'm on the highway my mileage steadily increases.

I've read a few of the messages in this discussion and I'll try some of these techniques, but let me share some of my observations and if anyone has any ideas about what's going on, let me know.

1. When I'm driving down my alley (5-10 mph)my display shows the power coming from the gas engine only. I take my foot off the gas and it shows the wheels charging the battery. I "feather" the gas pedal and the gas engine kicks in again. For the life of me I can't seem to get this car to run on battery only.

2. cdptrap says that "Short <=3-mile trips with many stops requiring complete engine OFF will kill mileage." But isn't this "city driving?" Isn't this where hybrid technology is supposed to help you the most? Toyota claims I should get better mileage in the city than I do on the highway. I'm finding the exact opposite.

3. When I'm driving in the city my engine rarely shuts down when I'm at a stoplight. What could I possibly be doing wrong? Even if I turn off the radio, seat heaters, fan, etc. I still find that if it shuts down, it tends to come back on in about 10-15 seconds.

4. In one post, a writer says he tries to have the battery almost drained when he reaches the top of the hill. According to my display, my battery never seems to discharge much at all. It always shows full or occasionally it's just one bar below full.

5. A couple posts talk about how they can get the car to run off of battery exclusively on the highway or even in their neighborhood during the last 2 miles of their commute. Again, I can't seem to get the electic engine to engage at all on the highway and only for brief moments when I'm driving in my suburban streets.

Since I expected to get nearly 500 miles on a tank and I'm only getting 265, I'm a little pissed off at Toyota right now. I took my car into the dealer to find out if there was something wrong. They found nothing and blamed it on my driving. So, I'll give them the benefit of the doubt for now and enroll in my local University of Hybrid Driving to see if I can do better. But I'm going to tell my dealership that, on delivery, they should spend less time on showing me how the cup holders work and spend a little bit more time telling me that if I don't drive just right I'll burn twice the fuel I expect.

kdhspyder · January 2006

These are very very good points for discussion. Hope this assists you in the future.

Your pt 1.
Basically all hybrids are ICE vehicles at heart. When you start up in the morning or after a long layoff the gas engine has to do the following: in winter heat the cabin, in summer cool it; heat the catalytic converter ( engineers? 800 deg? ); heat up the engine oil. All this takes place in the first 5-10 min of your driving which means that the ICE is running almost continually during this period. Thus you are driving a conventional ICE essentially for this short period. This is why short trips kill your Fuel Efficiency (FE). YOu start up run your short trip and turn it off again just as the hybrid system is ready to assist you.

Your pt 2.
Here is a huge source of discussion. Choose which is your city driving:
a. short trips to the store and school pick up 1-4 mi on local streets;
b. stuck in rush hour traffic crawling forward in Manhattan, DC, Chicago;
c. rolling forward slowly in heavy but moving traffic in the suburbs;
d. going stop light to stop light to stop sign to stop sign in a typical residentia neighbor hood.

As you can see City driving is quite variable. The EPA tests are based on type c. city driving.

your pt 3.
This is dependent on whether you are in the first 10 min period. After everything is warmed up and the battery is charged the ICE will normally shut down at every stop.

your pt4.
The battery should never reach full charge, nor should it go below 2-3 bars.

your pt 5.
It does take some practice as some of the experienced HH drivers have done to 'play' around with the system and your inputs to see how you can use it to drive on battery as often as possible. Pulse and Glide and a feather touch are critical. But again you can only do this after the vehicle is warmed up.

If you notice when I mentioned that I am able to get home on battery alone on the last 2 miles of my commute, my commute is 75 mi in each direction so by the time I'm near home everything is perfect to use the HSD system to it's full advantage after 90 min of driving. Esentially I coast the last 1/2 mi to a mile decelerating from 60 to 20, then keep a feather touch on the pedal to hold the speed at 20-22 while in my neighborhood.

Now to be precise, I'm driving a Prius and you have a heavier vehicle; the entire trip for me is dead flat, no hills; there is usually little traffic at 10:30 PM coming home.

Hope this helps. Keep us informed or ask anything you'd like.

cdptrap · January 2006

Added below due to formatting problems...

Q4.
When it was around low 40's or 30's, our gas-engine practically stayed on all the time on city streets, leaving the battery fully charged and unused. I actually posted here to ask about this. We have not been to areas with such low temps lately so unsure if it continues to happen.

Q5.
On freeways, the only time the gas engine shuts off on our HH is when we are on a long downhill that is steep enough that it can use the electric to maintain speed. The gas engine is always on otherwise. Again, this is not always bad, see footnote below.

NOTES
1. We have found it unnecessary to drive in full-electric in order to realize good gas mileage. Whenever the electic motors kick in to help the gas engine, the mileage will improve dramatically. So as long as we drive in such a way that the motors can kick in more often to help the ICE, our mileage will improve.

2. CRUISE really helps. I have heavy foot and regularly wear boots for farm work and it is impossible to feather light enough to use only electrc. So we set the CRUISE whenever possible, even on city streets. The drive-computer is good at deciding when to use all-electric, when to bring in gas-engine.

Finally, assuming there is no mechanical problems with your HH, it may just be practice time behind the wheels. Trying different tricks that we all use or tricks particular to your region and driving needs. It may also be the car needing time to break in if it has less than 3000 miles. Ours took 3000 miles to loosen up.

My wife and I are still learning, so you may find something new for all of us to know. Try it and please let us know how this all turns out.

cdptrap · January 2006

Ooops. 7932 miles, not 5...something something.

shilohlady · January 2006

One thing that I've found (with almost 15000 miles so far) is that its virtually impossible to get it going from a stop without using the gas engine. Having said that, what I do is accelerate at a reasonable speed (no jackrabbit starts but not extremely slowly either) and get up to the desired speed. You then have to take your foot totally off the gas and if the car is warmed up, the gas engine will likely shut off. You then gradually apply pressure to the gas pedal just enough to maintain the speed. On a flat or slight downhill, you may not need to add any pressure

This will often allow you to maintain EV mode for much longer.

This car coasts amazingly well - try it just to see. The longer you can go with little or no pressure on the gas pedal, the better. I also find myself releasing the gas and reapplying at various times while cruising, this can slightly increase fuel economy as well.

kdhspyder · January 2006

The acceleration, let up and feather/glide is exactly the same with the Prius..

upstateny5 · January 2006

Having said that, what I do is accelerate at a reasonable speed (no jackrabbit starts but not extremely slowly either) and get up to the desired speed. You then have to take your foot totally off the gas and if the car is warmed up, the gas engine will likely shut off. You then gradually apply pressure to the gas pedal just enough to maintain the speed.

I have found that to be true as well - get to the desired speed, take foot of accelerator and then gently reapply pressure on accelerator. I can usually go a fair distance before I need to call for more gas to maintain the speed.

mirak · January 2006

For the most part, my experience has been similar to other posts: It is usually almost impossible to accelerate from a stop in normal traffic without kicking on the gas engine.

However, one day, temps in the 60s, I had just finished a 100 or so mile stint on the highway. As I got back into town, I found I could accelerate normally to about 25-30mph on just the battery! It is the only time I have ever gotten my battery down to about the half-way point. Why can't the car drive like this all the time?!

Anyone else experienced this or know how to replicate it?

650vac · January 2006

It has to be tied to the temperature. When it is in the 40's, the ICE kicks in from just a roll. 60+, I can get it to 15-20 before it kicks in. This assumes a reasonable acceleration to prevent road rage from those behind.
Once I get moving and release the accelerator and then reapply, I can drain the battery down to purple and have the ICE kick in to recharge at any temperature at speeds below 40 MPH.

zenzonva · February 2006

I find the exact same thing, since November when it got cooler here (N. VA). For my daily driving routines Ive become completely accustomed to how the engine acts dependant upon the temperature. When its cold I know the ICE will stay on until a certain point in my drive whether Im pressing the pedal or coasting.

I have the Nav so I use both the Nav display and the odometer display to see what the engine is doing. The Nav display does not react as fast as the odometer display when the engine goes on/off. Also, when Im coasting and the engine is cold the odometer engine display doesnt show the ICE on but looking at the Nav display I can see via the current MPG bar that the engine is running cause the bar isnt full  it might be at 58, it might be less, but its not full. I can also feel the engine if I pay attention.

Once the engine is warm enough then I can coast as usual up to 40mph. On cold mornings which is most mornings right now, the battery will be fully charged before I get the engine warmed up. Ive even had it where it wouldnt charge any more (watch the blue area). That doesnt happen too often.

Just takes time to learn the car. My daily challenge is to NOT lose any MPG once I turn into my hood since its all uphill.

Good luck!

myladdie · February 2006

I've noticed a few times, when I'm rolling up to a stop sign for instance, a small surge when the ICE shuts off and the batteries kick in. Fortunately my foot is usually on the brake. Anyone else ever notice anything like this?

kdhspyder · February 2006

In driving my Prius I find the same as you. In explaining to potential client-buyers what the HSD does I've found it useful to use the following:

The Prius, Highlander/400h and new Camry hybrid are basically ICE vehicles. That is the ICE runs most of the time.

The major benefit of the HSD system is that it allows the ICE to shutdown for periods of time and not use fuel. Maximizing the length of these shutdowns is our goal.

In 4 specific conditions however the vehicles are using the ICE nearly all the time so essentially we are driving ICE-powered vehicles and our FE results should be the same as any similar vehicle:

A. when it's cold out the ICE must run nearly all the time to heat the fluids in the engine, heat the cabin and heat up the catalytic converter. This takes about 5-7 min in moderately cold weather.
B. (see above) For short trips the ICE never has the chance to shut down.
C. In situations of constant acceleration the ICE is normally in full use. ( heavy foot, stop sign to stop sign, climbing steep grades, etc )
D. At constant speeds over 65 mph where aerodynamics puts a severe strain on any vehicle the ICE is in use much of the time.

Knowing these restrictions try to counter them by taking fewer short trips, using P&G as much as possible, etc.

upstateny5 · February 2006

I have experienced that - doesn't seemed to be tied to temperature and it hasn't happened often but agree that it was good my foot was on the brake.

robroi · February 2006

What I have noticed when approaching a stop sign, with my foot on the brake, is that the "power meter" will be in the dark blue area, indicating regenerative braking. If I should run over a "bump" in the road during that time, the "power meter" immediately stops regenerating electric power and returns to the zero point on the scale. This action causes the vehicle to speed up (or surge) and requires a harder push on the brake pedal, since it is now on friction braking only. I wonder if this is what you are experiencing? Or is my situation unique?

discussion1 · February 2006

I have been using the Power Meter to help with acceleration lately. When there are no cars following, I gently tap the accelerator while keeping 1 eye on the Power Meter. As long as the needle stays inside the stripes region, the car has a much better chance of staying in electric only. When the needle leaves the stipes region, ICE kicks in.

I love the power of this car

, the only way to control myself is to use that Power meter as a reminder.

hhybridized · February 2006

So far loving my new HH but have some questions

1) what is normal discrepancy between NAV's MPG and actual? on my last tank i got 27mpg actual, but readout said 29.1mpg. the previous tank, it was 27mpg actual, 28.1mpg NAV. i usually stop filling when the pump clicks.

2) i noticed about 2.5gals left when gauge is on "E". any idea how much fuel is really left for other tick marks?

3) follow up to other posts... i also sometimes feel the lurch when braking to a stop sign on some bumpy road

:shades:

kdhspyder · February 2006

Most Toyota's, except the Prius, have a 2-3 gal reserve when the light comes on. In my past Camry's I could drive nearly 100 mi on Empty... with my wife screaming at me all the way..

not really, but I have run out of gas several times stretching the envelope when I'm alone.

All the posters on several sites note the discrepancies between the trip computers on the hybrids vs the actual hand-calculated method. The hand-calculated method seems lower by 2 mpg consistently.

IMO the hand-calculation is the key one. It's the actual gas you purchase by the actual miles you drive.

zenzonva · February 2006

I complete agree on the power meter

I would much rather watch that than the road sometimes. I find my mind is much more active driving this car because my goal is always to conserve fuel. I'm constantly watching in front, behind, the dash, 3 lights ahead, 2 lights behind... When I do lose focus I'm like OHMYGOSH I could have lost a 1/10th MPG!!!

I try and plan ahead as much as possible plus I want to know who might be buying a new rear bumper! But I also want to make sure the ICE is off.

I'm no longer an agressive driver. If the speed limit or my modest acceleration bother you, pick another lane! :P

PS: When I'm in a rental car all bets are off...though rental cars remind me how much I take for granted in the HH. Like holding down a button to make a window or sunroof open...who does that?

mmreid · February 2006

I've noticed that surge thing a few times but yeah, my foot was on the brake. Wasn't sure what it was. . .

On the other hand, with mileage up over 6,000 miles, my mpg seems to be improving all the time. Not sure if it is how I'm driving or the car just sort of "breaking in". I was a bit disappointed at first in my mpg but it's defintely going up and up. But don't know if it is how I'm driving or just the whole engine system breaking in. I defintely try and do lots of coasting whenever possible.

On the down side, while pulling out of my driveway, trying not to hit my husband's BMW, managed to scrape the passenger side of the vehicle (it's the widest car I've ever driven and I'm used to much smaller cars) on a tree in my driveway. Felt like a complete idiot and it is going into body shop at Toyota Dealership next week. I wanted to cry. Not even reporting it to my insurance company. You can't really see it unless you walk up close but somehow it's going to cost almost $700 to fix. Sigh. Double big sigh. I felt really stupid. But it's so much wider than anything I've ever driven before. In the months I've had it I've had a bit of a hard time figuring out "how wide" I was in this vehicle.

mmreid

82415 · February 2006

That is unfortunate. We are lucky so far but I myself have come close to a scrape a couple of times. It is certainly wide, as wide as my wife's old vehicle (a Previa) but now when I drive it I have to worry about the long nose as well (the Previa had a very short snout). It is very deceptive and it is a kudo to Toyota for them to package it (visually) a neat appearance.

Some say that the design is outdated but I think it will keep well and pleasing for much longer than more futuristic ones.

Thank you to others who post the scratch problems with the seat belt buckles. I checked last night and found a few early scratches, not too bad yet, though. I am trying to think up some solutions that also preserve the fantastic interior of the HiHY.

Good luck on your repair. It could have been worse, I can't remember where I read it but someone else had a side swipe before even the first car payment.

As far as the shake/surge/shudder problem, I don't think mine was a "surge". It did not pull ahead or anything like that. The ICE just shook lightly as in a bad idle on conventional car before it cut out as it should at a stop.

It is Sunday morning here as you can see I have more time to rant. Sorry.

kdhspyder · February 2006

We have an ICE version and find it just right. But since it's a Camry and that's all I've driven I'm very comfortable with the size. My wife was coming out of a Bronco so for her it's a midget truck.

The new iteration later this year should be significantly larger. It's likely to be on the Sienna platform like the Pilot is on the Odyssey platform.

gazguzler · February 2006

Friday I drove from baltimore to Miller Toyota in Manassas VA (with a few stops along the way). My salesman, Toyota Sam, took this photo of my nav screen showing I got 37mpg over nearly 90 miles of doing realistic PnG in 65F weather on a mixture of city&hwy.
http://www.vineeta.org/images/37
I stayed at the speed limit and rarely dipped below. I was not driving normally with no regard to mpg but I wasn't being a caddy in a golf cart, either. I was draining the battery as much as possible and doing long eleconly runs.
I have other nav screen photos in the mid 30s for distances greater than this.
I've seen a lot of folks here write that cruise control's good for hypermilin. I can't disagree with the experience of others but I never get numbers above 30 with cruise and I wonder if they'd compared their cc numbers with diligent PnG pedal feathering.
There's a pretty good chance that we'll drive to Chicago mid March with a stop in Indianopolis. I was hoping ulev would take me up on the offer (originally a bet) to meet and see if I can get good numbers on his car and vice versa. Not for money but to see if he has a lemon or if I can teach what I'm doing.
We should start planning a HH Jamboree and meet and greet, so anyone else in Windy or Indy (or on our route), please contact me brian vineeta.org
And anyone in the BmoreDC metro interested in comparing notes and drives, please contact. June the HH will be a year old and it would be worthy of a rally :-)

loneperson · February 2006

I have new 2006 4WD HH. I am a bit confused by the power meter and power flow mimic. Toyota says that the electric motors will power the wheels up to mid range speed but never defines what that is. I can't get much beyond 15 mph before the ICE takes over and from that point on the mimic shows occassional power from the battery in short bursts (less than 1 sec) even at steady speed. Is this normal?
Toyota says that during hard acceleration the electric motors will engage but this does not appear on the mimic either even when pushing into 4WD. Is this normal?
The kw meter rarely bounces above zero and the battery mimic says I have level 6 (not fully charged). The regenerative braking seems to be working fine but battery charge never increases. I have less than 100 miles on it and fuel economy is unknown but the on board info center tells me I'm getting the same as I did with my 02 Highlander V4 AWD so I am concerned that I'm driving a very expensive ICE with limited electric assist. So if people can tell me what I can expect to see I'll know if I should go back to the dealership to complain. Thanks

kdhspyder · February 2006

First it takes some time for a) you to be come familiar with the vehicle and the way it operates; it's very personal thing. b) the vehicle to break in ( figure 5000 mi min ).

Answer to your first question: Yes it is normal for the electric motor to supply power for an instant or two ( see below ). It's part of the design of the HSD that the battery never reaches full charge and should never fully discharge. This is why it should last for the life of the vehicle. ( see prior posts in the Great Battery Debate ).

Read here and on other sites some of the fine suggestions for improving your methodology. Do you have a Nav-equipped model or the standard trim?

Here are some key points to consider when driving and planning your time in HH.

All hybrids are basically ICE vehicles. Most of the time they are just like any other vehicle in it's class. an HH is just the same as an ICE HL most of the time!

The benefit of the HSD system is that it allows the ICE to shutdown frequently thereby burning no fuel. Using the best features of the system, in city driving you might be able to shutdown the ICE as much as 50% of the time; on Hwy driving as much as 20% of the time; depending on your individual input and your itineraries it should average about 30% of the total time. The more a driver can create times for the ICE to shutdown the less fuel will be used. It's perfectly obvious.. but

A) in cold weather the ICE has to run more because it has more work to do ( heat the cabin, the engine fluids and the catalytic converter );

in accelerating the ICE is running nearly all the time;
C) on short trips, see A), the ICE is running for the entire time;
D) during high-speed driving you run into significantly increased aerodynamic resistance which makes the ICE work harder.

In all four of the situations above you are essentially driving a 3.3L ICE Highlander or in the case of the autos a 1.5L Prius or soon a 2.4L Camry.

Our goal as drivers is to maximize frequency of times and therefore the amount of time that the ICE's can shutdown.

Some situations are beyond our control. If you must go to pick up the children at school and return home right away, this short trip will be on the ICE only. This kills your mpg averages.

A number of posters have asked on this forum about the same seeming lack of capability. Read back and you will see some great suggestions. Remember though you are driving an ICE vehicle nearly all the time. But you can coax it to shutdown frequently.

kdhspyder · February 2006

I sell Toyota's and own a Prius. I have made a point of trying to understand the system and to explain it in normal-folk speak.

While I drive the Prius the HH is the same essentially.

What you should expect initially depends a lot on your particular circumstances.
1.) How long are your trips?
2.) What kind of weather have you been having?
3.) Your terrain?
4.) You answered already that it's brand new, so breakin is not reached yet. Same with familiarity with the techniques.
5.) Weight in the vehicle? Cargo?
6.) Tire pressure?
7.) What type of 'city' driving do you do? I can think of 4 different types of 'city' driving.
8.) On the highways near you are they dragstrips or does traffic flow in the 55-65 mph range>

I also have a V6 AWD ICE Highlander. Typically we get ~18 mpg combined maybe slightly higher. Use this as a baseline.

One thing that has developed from all this experience with hybrids all over the country is that drivers are much more aware now of factors that can affect FE, both plus and minus; e.g. were you aware that there was such a thing as summer gas and winter gas and since winter gas doesnt burn as efficiently you need more of it? I didn't.

cdptrap · February 2006

Gaz,

Can you take a few moments and share what you did on this trip?

Someone posted that he is watching the needle and making sure it stays in the stripes region. I have been trying it and it seems to work.

Thanks in advance. Did not see this until now, have not been reading in a while.

worsthhdriver · February 2006

Dear All,

I just want to say thanks to all who have provided such thoughtful replies to my inquiry. Thanks to you, I'm a hell of a lot smarter about hybrids and I have some good ideas to help me get improve my car's performance.

One big comment: Even if I'm able to improve my mileage, I have a 4 mile commute every day, so clearly I'll never come close to getting the EPA mileage on this car. I'll be lucky to get 20. So, I'm still pissed off at Toyota and my dealership for not disclosing something this basic and universal before I bought it. If I knew then what I know now, there's no way I'd buy this car. :mad:

poodlgal · February 2006

I've got to chime in here. I have a 4WD HH (not limited, so I can't see all the fancy screens)with about 4000 miles so far, and I keep a gas log at each fillup. My "pure" highway mileage averages 25-26MPG (used full tanks on long road trips) and city is pitiful, usually 20. Last tank, which was ONLY city driving was 16. The weather here in Wisconsin has been COLD and the electric engine hardly kicks in until the temp gauge is at least 1/2 way between cold and hot, even with the heater fan and all other accessories off. Makes for a chilly drive, but I wanted to test it out. I try pulse & glide, driving slowly, coasting when possible, etc., etc., but the mileage still is pretty poor.

Yes, I still like the car, having bought it because of its size, reliability, and the simple fact that I want to support hybrid technology. I knew I wouldn't get the mileage of a Prius, but I did expect it to be closer to the HH's estimated EPA mileage - or at least, not below 20 MPH. I'm hoping that the mileage will improve with warmer weather, but I am a bit disappointed that I can't do better now.

If anyone else has comments about winter MPG, I'd love to hear them.

wwest · February 2006

It might help a bit if you disable the A/C compressor during the winter months. The way the automatic climate controls work is to CHILL the system airflow first and then reheat all or a portion to maintain the cabin comfort level.

The only benefit from this when the OAT is significantly below the cabin comfort level setpoint is to potentially dehumidify the incoming airflow. Since cold air in the wintertime is already quite dry this is usually a non-function.

So if the A/C is disabled the energy to run it will remain in the batteries, the heating cycle will be more efficient, and the engine will not need run so often to keep the coolant HOT.

The cost and complexity of having the A/C system be a fully reversible heat pump is so low that I don't understand why it isn't. With a heat pump even slightly warm engine coolant could be used to heat the car on the coldest day.

judi3 · February 2006

I drive my AWD HH in the cold Chicago weather,a little highway with a lot of stop and go in traffic. The least amount of mileage was 24MPG highest was 28.5MPG when the weather was warmer and the heater was not used. I do try to glide whenever possible.

typesix · February 2006

AC compressor in auto climate control will not activate if cabin temp is below setpoint. Cooling coil also has temp sensor that won't allow discharge air to go below 40 deg F or frost will form on cooling coil by limiting compressor operation.

wwest · February 2006

Place bets..???

The Prius has an economy mode for the A/C, but I was asured by Lexus that the RXh and HH did not.

discussion1 · February 2006

I am in CA, our weather is much milder than where you are but mileage dips anyway when it gets below 50-F.

We get 26-28 mpg as long as local temperatures stays above 50-F.
Between 45F-49F, it still can get around 24-25 mpg. Once it hits 44F and below, mileage dips to 22-23 mpg. Below 44F, the ICE runs much longer and more often with practically little to no electric run possible.

My wife is better at getting good mileage so I am learning from her right now

. She uses two techniques in city driving. If terrain is relatively flat, speed limit is 35-mph or below and there are no cars following or there is a clear lane for cars to pass, she accelerates from stop by keeping the power-gauge needle close to or inside the stripes region. This makes for a slow steady pick-up to 30 mph and beyond.

If there are cars following, she just accelerates a little faster to posted speed, then foot off gas to get the ICE off, then she maintains speed by keeping the needle in the stripes region of the meter.

Keeping needle in the stripes region means the car may slow down some so she repeats the process to bring the car gently up to speed. She never lets the speed drop below safety-point or more than 10-mph before picking up speed again slowly.

It is not easy for me to be so gentle given this car's power is so addictive but I am learning.

kdhspyder · February 2006

If there are cars following, she just accelerates a little faster to posted speed, then foot off gas to get the ICE off, then she maintains speed by keeping the needle in the stripes region of the meter.

Pulse and Glide then Feathering

Keeping needle in the stripes region means the car may slow down some so she repeats the process to bring the car gently up to speed. She never lets the speed drop below safety-point or more than 10-mph before picking up speed again slowly.

Repeat Process

The power is enticing tho isnt it?

discussion1 · February 2006

Yes, HiHy Pause & Glide & Feather (P&G&F), not Prius Pause & Glide & Feather as someone said once.

When feathering the HiHy, the ICE can still run periodically and when it is not, the battery supplies power (full electric) to keep the car moving. When the ICE does run, the mpg is still great. We no longer rely solely on CRUISE. Feathering allows us to favor electric over maintaining speed while CRUISE will use the ICE to maintain speed.

Ambient temperature dictates how much feathering we can do. When it is downright cold (by CA standard), the ICE runs no matter what and mpg sinks.

The power is enticing tho isnt it?
Worse than enticing

, this car simply begs to be driven. It simply begs to go full-throttle on an open road one moment and a twisting narrow steep mountain road the next.

Gas is back up into $2.80+ range in our area, got to slow down now

.

upstateny5 · February 2006

Your experiences are very similiar to mine in terms of the mpgs as it relates to temperature changes. However, there are days when the temps are over 70 degrees and I have a problem getting over 26 mpg - other days are easy.

Recently I found a couple of "back" roads where I can often drive without someone behind me. I made many trips on this back road to a shopping center and often drove on electric alone. Guess it helped as my last fill up showed that I had gotten 29+ mpgs for something like 271 miles.

I do have a question though - my battery level often dropped to a lower third while driving on electric. Will the car take over and automatically charge the battery or should I kick in with gas to make sure everything is ok?

kdhspyder · February 2006

Part of the design of the HSD system in the software is that when the cpu 'senses' that the State of Charge ( SoC) of the battery is low then the ICE kicks in to charge the battery even if it's not driving the vehicle. Example: when you first turn on the vehicle nothing happens and you sit there for a while the ICE will turn on to just charge up the battery - assuming it's not freezing upstate ( from the Capitol district area myself ) in which case the ICE may turn on to charge the battery and heat the cabin.

discussion1 · February 2006

COngrats on the 29+ effort! Those back-roads are great!

Will the car take over and automatically charge the battery or should I kick in with gas to make sure everything is ok?

The car will automatically charge but charging by ICE burns gas so we are trying 2 approaches to maximize electric usage and minimize ICE charging.

First approach is start coasting as soon as traffic will allow when coming to a turn or a stop. The coasting charges quickly and sets up for the next electric run. This works real well for us.

Second approach applies to driving long stretch of fairly flat road with no stop and no turn. When the battery drops to 4 bars (~30%), we bring the car to 5-mph over desired speed and then let it coast back down to previous speed. This normally yields 2 more bars and good for another mile or more depending on terrain. When picking up speed, the ICE sometimes kicks in but we just make sure the power-meter needle stays as close to the pile of stripes as possible to minimize gas consumption.

All these little tricks were not invented by us, we got them from this forum and from friends who own Prius. We did have to tweak them for the HH and our local road conditions. Getting the power-meter needle to work within the stripes region as much as possible is really the key for us. Once we could do it, everything else seems to fall in line.

upstateny5 · February 2006

Thank you and discussion1 for your responses. Yes, I am from upstate NY (south of Plattsburgh) but the car is wintering in warm Florida.

I don't have the navigation system but do have ScanGauge which is invaluable to me in showing the mpgs that I am getting for each trip.

Guess we are all experimenting with driving habits - I am learning more and more about some of the back roads here and especially the ones with lower speed limits where I can really improve the mileage and not worry about someone behind me (if I'm doing the speed limit they can either pass me or stay back there).

poodlgal · February 2006

When you say "in the stripes" are you referring to the wattage gauge on the left side of the dash or to something on the Nav screen in a limited model? Please help translate!

Having a base model gives me a lot fewer clues about what the car is doing than I think some of the limited features can show. Seems to put me at a relative disadvantage for playing mileage games.

Thanks for all the input, folks.

discussion1 · February 2006

... "in the stripes" are you referring to the wattage gauge on the left side of the dash...
Yes, sorry for not being clear. Staring at the wattage-gauge/power-meter needle is also dangerous but we have learnt to use peripheral vision to do this.

kdhspyder · February 2006

Also the more you drive and get used to the methodology of the HSD system you will become familiar with the feel and sound of the HH to know when you are 'in the stripes', 'gliding', when to 'pulse', etc. You won't have to watch the guages at all.

It's not a whole lot different than owning a manual tranny. After a while you listen for the shift points and 'feel' what your vehicle wants.

wwest · March 2006

Keep in mind that there is a reason diesel fuel on a per unit basis is now more expensive that Gasoline. That's because the industry is using "value" pricing and since diesel fuels have more latent energy than an equivalent volume of gasoline it is priced accordingly.

Basically that means regular gasoline fuel, 87 octane, also contains more latent energy than an equivalent volume of 92 octane.

As is the case with diesel fuels the "secret" is finding a way to extract, use that energy without damaging the engine.

The "secret" to extracting more energy from 87 octane vs 92 octane gasoline is called knock/ping sensors, electronically controlled shifting, and DBW, e-throttles.

And yes, you will sacrifice some level of performance at WOT as you approach the engine's redline but otherwise the extra cost of premium fuel is actually detrimental to fuel economy.

But be careful with this information, if word gets back to the industry we'll be paying more for 87 octane than for 92.

discussion1 · March 2006

I agree that we do not purchase higher octane gasoline to improve gas mileage. Higher octane gasoline are meant for higher compression (higer performance) engine and has little to do with gas mileage.

General wisdom is that engine with compression ratio of 9.5:1 and lower can safely use 87% Octane gasoline. Engine with higher compression ratio should use 91%+ Octane gasoline.

There are 2 important parts to this Octane thing for HH owners.

The regular Toyota 3.3L V6 is listed with compression ratio of 10.8. It is a high compression, "high performance" engine. I do not know if the detuned version in the HH has lower compression ratio. The on-line HH spec at Toyota has a "Legal Disclaimer" stating that the HH V6 engine speficiation is measured with 91% Octane gasoline and use of lower octan gasoline may result in performance decrease.

The HH manual does recommend 91% octane gasoline though it says 87% octane is usable.

With knock sensors and all sorts of technical gadgets, one can certainly use 87% octane gasoline safely in the HH. It is very likely that in normal driving at low altitude or flat terrain, 87% octane will perform just fine.

Those of us who need every ounce of performance either because of high altitude or steep terrain driving probably should consider staying with 91% octane.

I think we need to experiment for ourselves to see which grade best fit where we drive most.

shilohlady · March 2006

Actually, at high altitude, you can use LOWER octane. That's why in CO and UT, "Regular" gas is 85 octane and works just fine for cars designated ro 87 octane.

discussion1 · March 2006

Ooops, you are absolutely correct about lower octane at higher elevation, I made a mistake, should have checked my old note books first.

If I remember correctly, temperature and humidity can also affect which grade to use. I know people who live in Sierras that switch octane grades for winter and summer, do not recall which grade for which season. It gets quite scientific after a while.

In any case, for best performance or for performance up to HH specification, I will stick with 91% octane.

2tees · March 2006

I've been following this forum since May 2005. Took delivery on an HH Ltd in July. It now has 7500 miles. I'm wondering if any owners have experienced three things the could have safety implications?

The first one is a complete lose of acceleration. The first time it happened I was pulling out of a snow covered driveway that had a very slight incline. I pressed the accelerator pedal three of four times over a period of 15 seconds but nothing happened. I then waited about a minute for traffic to pass and off I went. When I asked the dealer's service tech he said,"Turn the engine off and on. Just like a computer."

Then, a couple of weeks ago, I was coasting on a snow covered road. I pressed the accelerator pedal and nothing happened. I continued to coast for about 500 feet, pressed the pedal again and it worked. I feel uncomfortable with the thought that this might happen again when I Really need to accelerate.

The second experience has to do with steering. Driving in a straight line, no snow this time, I occasionally feel a slight resistance in the steering wheel during normal steering correction. It feels like the front wheels are trying to move out of a phyical grove in the road.

Lastly, under hard acceleration I experience strong front torque steering -- the car wants to turn left or right.

I suppose there is a ton of technology in the car some of which is first generation and some that has been improved. What makes me feel uncomfortable, in all three examples, is the HH may not behave according to driver input or expectation.

I would appreciate comments.

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