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Hybrid Vehicles Toyota Highlander Hybrid Toyota Highlander Hybrid Driving Tips & Tricks
428 messages, Last post on Oct 16, 2009 at 6:44 PM
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Bear with me here ... I'm a very curious nuclear engineer ... Some of these have been asked before, but no one seemed to have really technical answers. 1. Does the "B" engine braking position on the shifter truly regenerate electricity and charge the battery? I've read contradictory statements that it does and does not. Also, when on level ground, the car will move and accelerate slowly on its own when in the "B" position, as if it was no different than the "D" drive position. This seems sort of strange. 2. Is the fuel tank size really 17 or 19 gallons? I've read both numbers, and am inclined to believe the 17 gallons based on my experience. 3. Why are there several ticks in the region around zero kW on the kW meter? Why not just one tick for the zero mark? 4. Why does the kW meter indicate a positive (+) number when only the ICE is powering the wheels? Obviously, this meter is indicating more than just electrical power transfer. Perhaps a conversion factor from horsepower to kilowatts is applied here? 5. Sometimes the kW meter reads zero (right in the middle of the many tick marks), yet the power direction indicates "charging" the battery when drifting down the highway at high speed, or even down a gentle hill. Shouldn't the meter read negative (into the blue zone)? 6. For charging the battery, is it more effective to brake gradually or drift down (kW meter basically reading zero), or to apply the brakes firmly and force the kW meter deep into the blue zone? 7. Has anyone figured out how and where to tap into the computer system, specifically to get at the data that is used to calculate MPG? I have the basic HH (couldn't afford all the luxury features that came with the Limited), but I really would like to calculate total MPG for short trips, whether it's a 5 mile trip or a 50 mile trip, without having to refill the tank. I know the information is somewhere in my HH's little brain, since it will display a 6-second instantaneous MPG rate. For you computer nerds out there, I bet you could make some money if you came up with an interface and a program to download all this hidden data into a PDA or laptop. I would gladly spend $25-$100 for such a gadget. 8. Pulse and Glide method: Is the "glide" portion of this technique the same as being in "N" neutral? Please explain the technical differences if they are not the same. Does pulse and glide cause more wear and tear on any mechanical components or electrical relays? 9. What is the algorithm or equation that determines when the ICE switches on/off? What might some of the not-too-obvious inputs be? Is car attitude (levelness) one of them? Perhaps someone could do a whole lot of experimenting and figure it out. 10. Non-hybrid specific: why can't auto manufacturers make a linearly-accurate fuel gage? This just blows my mind, especially with today's technology! There are zillions of accurate tank level measuring systems out there in industry, just not in the auto industry! geez - I guess I could have started a new discussion board here! |
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Replying to: carz89 (Aug 14, 2005 9:08 pm) However, try this link to get you going for your question 7." |
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Replying to: carz89 (Aug 14, 2005 9:08 pm)  Here are my guesses . . . please correct. “1. Does the "B" engine braking position on the shifter truly regenerate electricity and charge the battery?” Truly doubt it. I often hear the engine revving when I’m in this gear and can see it on the screen. I believe it’s braking WITH the engine. Also, it’s different from drive in that when you release the accelerator it won’t glide. “2. Is the fuel tank size really 17 or 19 gallons?” At cut off, it’s around 17 in your tank (or even less) but you can get more than 19 in there if you go beyond this. By the way, some nozzles have a vapor vaccum. If your nozzle is in the gasoline, you’re putting in and sucking out gas at the same time. Make sure your nozzle is out of the liquid. “3. Why are there several ticks in the region around zero kW on the kW meter? Why not just one tick for the zero mark?” Please refer to the previous answer about how many angels can dance on the head of a pin . . . who cares on this one? Never even thought of it. “4. Why does the kW meter indicate a positive (+) number when only the ICE is powering the wheels? Obviously, this meter is indicating more than just electrical power transfer. Perhaps a conversion factor from horsepower to kilowatts is applied here?” Yes, you got it at the end. “5. Sometimes the kW meter reads zero (right in the middle of the many tick marks), yet the power direction indicates "charging" the battery when drifting down the highway at high speed, or even down a gentle hill. Shouldn't the meter read negative (into the blue zone)?” It could, I guess. But it seems to only work in the +. It would be better to see how much energy it’s getting back. “6. For charging the battery, is it more effective to brake gradually or drift down (kW meter basically reading zero), or to apply the brakes firmly and force the kW meter deep into the blue zone?” Slow. A firm press actually uses the conventional brakes and you get no regeneration. There’s also the power assist, where the car thinks it’s an emergency and clamps down the calipers for you and then you get zero regeneration. ”7. Has anyone figured out how and where to tap into the computer system, specifically to get at the data that is used to calculate MPG? I have the basic HH (couldn't afford all the luxury features that came with the Limited), but I really would like to calculate total MPG for short trips, whether it's a 5 mile trip or a 50 mile trip, without having to refill the tank. I know the information is somewhere in my HH's little brain, since it will display a 6-second instantaneous MPG rate. For you computer nerds out there, I bet you could make some money if you came up with an interface and a program to download all this hidden data into a PDA or laptop. I would gladly spend $25-$100 for such a gadget.” You can bet it’s gonna cost you more than that and few are going to dabble there till their warranty’s up. ”8. Pulse and Glide method: Is the "glide" portion of this technique the same as being in "N" neutral? Please explain the technical differences if they are not the same. Does pulse and glide cause more wear and tear on any mechanical components or electrical relays?” On a normal car, it would be like neutral with the engine ala Kerouac’s On the Road (which I did all the time). But in the HH neutral gives no regeneration and you inevitably slip from one arrow to the other. Definitely don’t do this in neutral in a HH. “9. What is the algorithm or equation that determines when the ICE switches on/off?” Of course, I don’t know but I wish T had made this so you could set it yourself. How nice it would be to say only electric, for instance? Or even to have the equivalent of cruise control but where the car would pulse and glide for you between a high and low you’d set. Because P&G’s damn dangerous now as you have to watch the instrument panel every second. |
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Replying to: carz89 (Aug 14, 2005 9:08 pm) http://techinfo.toyota.com/ It is a Toyota site that has all technical documents and user manuals in PDF form. When you access each document, it pops up so you will need to enable "Pop-Up" for your browser. There are wiring diagrams & Toyota Diagnostic Tester info for the HH. Whoever is handy with a diagnostic unit can easily use such info to tap into the on-board drive system and decipher the data being passed to the instrument panel display. This can be like the system an owner did for his Prius (another poster has link). Whoever can do this and provide a read-out for us will likely charge beyond $25. It will involve wiring connection and installation of a device that provides such read out. |
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Replying to: carz89 (Aug 14, 2005 9:08 pm) Can only answer #1. The info below is based on observing the arrows/flows on the Energy display on one of our trips. "B" - Engine braking, enginge does not charge the batteries as shown on the energy display. No flow into or out of the engine but we can feel car slowing and engine is reving. "N" - No charging at all. Display shows no energy flow anywhere. "D" - When driving, engine sometimes charges the batteries via the front motor. This is normal, it charges whenever it needs to. "Coasting in D or B" - foot off accelerator, car is coasting in D or B, charging occurs automatically from all 4 wheels. Have not seen engine charging the batteries when coasting in these modes. "Gentle Braking in D or B" - Tricky. Often, when we coast to a stop, regeneration is happening before we apply the brakes. Soon after we apply our brakes, regeneration stops and energy display shows no flows anywhere. While we believe we were gentle on the brakes, the car thinks otherwise and actuates the real brakes sooner than we think. This cuts off regeneration sooner than we think. "Hard braking" - No charging. Energy flow display shows no flows at all anywhere. "Pulse and Glide" Excessive Wear question - I do not believe so. It is all just normal driving, no hard acceleration, no hard braking so only "normal" wear and tear occurs. We do pulse and glide a lot on local roads and it helps with our MPG. We are now up to 26.5-27 MPG mixed at 2300+ miles. We also stay in the right lane more and coast to a stop as much as possible before applying brake pressure. Using analogy from flying, streets are like taxi ways, freeway on-ramps are like take-off's while freeways or high speed expressway are like crusing at altitude. Drive/taxi carefully and slowly but punch it on entering freeway/take-off and then cruise it at altitude.
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Replying to: carz89 (Aug 14, 2005 9:08 pm) The owner's manual clearly says 17.2. 3. Why are there several ticks in the region around zero kW on the kW meter? Why not just one tick for the zero mark? No kidding. I don't get this, either. 4. Why does the kW meter indicate a positive (+) number when only the ICE is powering the wheels? Obviously, this meter is indicating more than just electrical power transfer. Perhaps a conversion factor from horsepower to kilowatts is applied here? Conversion from HP is my assumption. If you hit car pages from other nations (you know, that whole rest of the world which is on ISO units) they report power in kW, not HP. 5. Sometimes the kW meter reads zero (right in the middle of the many tick marks), yet the power direction indicates "charging" the battery when drifting down the highway at high speed, or even down a gentle hill. Shouldn't the meter read negative (into the blue zone)? I'm glad I'm not the only person to wonder this. Makes no sense to me, either. 10. Non-hybrid specific: why can't auto manufacturers make a linearly-accurate fuel gage? This just blows my mind, especially with today's technology! There are zillions of accurate tank level measuring systems out there in industry, just not in the auto industry! No kidding. This drives me bananas in all cars... |
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Replying to: carz89 (Aug 14, 2005 9:08 pm)
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Replying to: lizzie428 (Aug 15, 2005 4:48 pm) |
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I realized something's killing the consumption, particularly on short runs. I can have a full battery but when I start (after a few seconds of READY), even when parked or rolling slow, the engine will start and won't stop no matter if completely still or moving. The only explanation I can think of is that the engine always starts to warm up the catalytic converter (there MUST be a more energy efficient way to heat up that tiny little thing!). That’s doesn’t bother you if you’re straight onto a road beginning with I- and you’ll be cruising at 70mph but to roll through a neighborhood it’s pointless. I take my wife on a 2.5 mile commute. I get 15 MPG there and 30 MPG back (and it’s level). In my old 4Runner I would switch off the engine and roll in neutral, which you can do in the HH but you can’t start back up until you’re stopped and put it back in Park. The Runnner could statt in N or P. So, you could start on a roll. If there was away around this early engine running, you could save significantly on short cold runs and at least 2mpg on total use. By only using the engine when you needed it and not to warm up a catalytic converter, which isn’t only wasteful but you must emit more pollution this way (why not just let normal use of the engine warm it up? Using the battering for the first 3 minutes doesn’t pollute). Can anyone think of a way to prevent this early engine start-up or starting the car while in N?
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Replying to: gazguzler (Aug 16, 2005 10:24 am) We observed a slightly different behavior: 1. Approx. 10 seconds after READY, ICE comes on. Display shows it charges the battery even when battery already has 6 bars. 2. Charging continues for approximately 20 seconds then display shows charging ends, no energy flows anywhere. ICE remains on. Battery remains at 6 bars. 3. ICE continues to run for about 10 more seconds and then shuts off. Total time from start-ready to ICE shut off is about 40 seconds and ICE stays on for about 30 seconds. This all happens consistently in ambient temperature range of 60-78 degrees. Will it charge longer if battery is less than 6 bars? or will it stay on longer to heat the converter as you surmised if ambient temperature is colder? We are not sure. We paid attention to this after reports of HH not starting overnight and HH ICE runs too long (NYT article). So far, we have noticed no such behavior. |
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