Did you read this thread from the beginning?

I need to check out the idle fuel consumption rate the next time I drive to better answer this. At highway speeds, it is very common to see the iFE above 90 mpg or even maxed out at 99.9 mpg (according to the energy flow screen) when your foot is off the accelerator. I'll have to double check the next time I drive to figure out at what speed the iFE reaches 60 mpg with the engine idling.

This is absolutely NOT true. You clearly do not know what you are talking about. Low speed does not equal high fuel economy--especially in a non-hybrid. My 45 mpg trips were driving near the speed limits which were mostly 25 miles per hour to 45 miles per hour. I also dealt with stop lights and some stop signs. I tried to time the stop lights.

 

OK. I just took the HiHy to pick up lunch and got the idle rate. After reaching its normal operating temperature, the engine idled at a rate of 0.3 gph. 60 mpg x 0.3 mpg = 18 miles per hour. At 34 miles per hour (a speed at which it is easy to have the engine running without knowing it), the idle rate would have to be ~0.6 gph before the iFE would drop below 60 mpg.

Now, you may think that since you have a hybrid, the engine always shuts off when you take your foot off of the accelerator. This is not entirely true. With the Toyota HSD vehicles, it is a bit complicated. It takes more than just getting up to the proper temperature to enter into full-hybrid mode. I believe many HSD drivers are totally unaware of this. I've posted this link already in this thread, but I'm guessing you did not check it out.
http://techno-fandom.org/~hobbit/cars/five-stages.txt

I really do not understand why the warmup stages are as they are, but that's how it is. If you at least understand them, you will know the "rules" for getting to full hybrid operation.

 

Basically, it has to do with three things. Temperature of the engine as measured by coolant temperature (engines operate more efficiently when warm enough for efficient fuel vaporization, warm oil lubricates better, etc.), temperature of the catalytic element (needs to be hot to function to levels required by EPA standards, and cabin comfort (coolant again). On a secondary note, it has to do with another thing, battery temperature (which is raised to a minimum temperature for better efficiency by discharding/charging events).

On Toyota HSD vehicles, all of these temperatures are inputs to the ECU and some of them can be overridden or modified by the ECO switch, but not all of them. Similar temperature rules probably exist for most other hybrids. The reasons that some of them cannot be overridden usually have something to do with EPA emmisions requirements or other vehicle manufacturing requirements imposed by government (airflow warming requirements for the windshield defroster in the defrost operating mode for example.)

 

I understood all that stuff. What I don't understand is why the transition from Stage 3 to Stage 4 is the way it is. Why do you have to come to a complete stop with the engine running and wait 7 seconds (that's what it is in the HiHy) before you can do this transition to full hybrid operation? This doesn't make sense to me. If you meet all the temperature criteria, isn't that enough?

 

Where I drive most often (SW PA), there are many circumstances that make hypermiling difficult, but I have experienced > 35 mpg over 20 - 30 mi stretches.

Minimize all the parasitic losses first,
a) Low viscosity oil (e.g. 0W-20)
b) Inflate tires to a safe maximum for your brand of tire (I keep my Dueler H/L Alenzas at 40 psi).
c) Time longer trips to later in the day (I experience a 0.9 mpg drop for every 10 deg below 80F) - but see my commment re A/C.
d) Minimize use of heater (below 30 F) or A/C (above 90F).
e) Use EBH on a 4 - 5 hr timer cycle when below 30F.
f) Block the two front grille vents when below 70F (3/4" pipe insulation works well).

Drive in a way to encourage full hybrid mode and allow the ICE to disengage. This is what allows the HiHy to be able to exceed 40 mpg, and why the non-hybrid Highlander can not exceed 38 - 39 mpg on level surfaces, even at a steady 20 miles per hour.

a) combine trips to be able to drive nearly continuously 45 - 90 minutes.
b) pick a route that allows speeds 35 - 50 miles per hour with few or no stops.
c) allow ICE to go through its warm up cycle.
d) pulse, feather, glide when ICE is warmed up
e) use neutral on < 6% downhill grades (only when safe to do so) when battery is at 8 or more bars

 

Has anyone installed a block heater on their HH besides Rudywalker101?

Rudywalker101

I have been following this site for sometime now and have learned alot from many of its members. I have installed a blockheater, added a scan gauge as well based on member information. Thanks for your additional hypermile suggestions. I noticed you added the grill block to your highlander and wanted to know if you could elaborate on the installation. Would it be possible to get a picture? Based on using the tubing maybe you installed the tube over the long slots top center of the bumper?
I have wanted to do this for sometime now but have not found it mentioned anywhere on the web. I am in South eastern PA by the way so this morning it was 15-16 degrees and the block heater would be nice to have right now.

Thanks,
Lenny

 

Correection for my post above.
I am interestd in adding the grill block material not and engine block heater (I have one) if anyone has done this before please provide your input.

Thanks,
Lenny

 

I use a radiator air block for the entire winter as long as outside temperatures are less than about 70 degrees. This is my second winter that I have used a radiator air block.

I cut two pieces of corrugated cardboard and place them directly in front of the radiator. One on the left and one on the right. A small 2 to 3 inch gap remains in the center between the two pieces which is also occupied by a vertical metal bar directly in front of the radiator. The pieces extend down all the way to the bottom of the radiator (visible in the air scoop area below the bumper) and all the way to the top.

The cardboard is waterproofed first with some Thompson's Water Seal or equivalent. You can also paint them black for a stealth appearance. Install the cardboard by removing the 6 plastic pin fasteners that hold the front grill in place at the very top just below the hood. You do not need to remove the grill. The plastic fasteners have a center pin that you pull up which releases the pin quite easily and the fasteners can be used over and over this way.

With the fasteners out, the grill can be flexed slightly forward creating a slot that allows the cardboard to be slid into the space behind the grill and in front of the radiator. A slight horizontal crease in each of the two cardboard pieces about 10 inches from the bottom lets the cardboard bend backward as it reaches the bottom of the radiator for a better fit.

The cardboard fits snug if cut to the right height and does not need anything to fasten or keep it in place and it does not move around at all or flap even at highway speeds. It also will not damage the radiator as it is relatively soft and compliant.

I always monitor engine water temperature on my Scan Gage and there has been no issue of potential overheating in winter weather. The vehicle warms up slightly quicker in winter with the radiator air block in place. It also seems to retain heat a bit better at low speeds to reduce engine turn on due to water temperature falling below the minimum threshold.

Note that I use an engine block water heater for about 3-4 hours each morning also.

 

Two shortcuts for the above post.

Buy black "foamboard". Available at office supply stores. No need to paint. No need to waterproof.

 

I don't think my wife would let me strap carboard on the front as a radiator block. Does anyone know if any commercial products exist which do this? I"m thinking it would have to be a car bra, which I'm not fond of, but might be acceptable to the wife.