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The Honda hybrid system does not have a pure electric mode. When it is moving, the engine is running.
You can get the electric motor to power the car by itself. If you own one, toggle over to the information display page that shows the battery level. As you are driving you can see how the energy flows to and from the car, battery and gas tank. When you see an arrow pointing from the battery to the car by itself, that means that the electric motor is keeping the car moving. See this youtube link of someone doing it:
http://www.youtube.com/watch?v=1vMAb5DOl5Q
When this happens, the gas engine is still turning but it is not running because the hybrid control computer has shutoff the fuel to the fuel injectors.
http://www.youtube.com/watch?v=xmDkc8SEvwc&feature=related
Possibly I should have said that the engine is turning over whenever the car is moving. Strange in a way, because that means the electric motor is having to push the cylinders, which takes more energy. But I suppose that is because the IMA has the electric motors around the driveshaft, making it impossible to completely disconnect the electric from the mechanical (unlike the Toyota and Ford hybrid systems).
I read your post and agree technically with everything you said. Although, I'd still like to defend my previous recommendation. But first, it was correct of you to point out that when using the energy stored in the battery, some energy is lost in the conversion process. I call this "The Conversion Tax" and had planned to do a couple of posts on this subject with some specific recommendations at a later date. And of course, the conversion tax must be paid when storing the energy in the battery too - so you have to pay the tax BOTH ways. So you are correct that if you use the battery power to maintain speed you are going to pay the tax twice, as opposed to maintaining speed using gas only.
You also pointed out that the battery energy is supposed to be used for acceleration. But remember, some of my other posts were geared towards reducing the amount of overall energy used during acceleration. That will also use less stored battery energy. The end result is that more energy is left in the battery. And since normal driving with the Insight also further charges the battery, you often can reach a point where the battery is almost at full charge. And now it is time to brake. PROBLEM... If your battery is full before you start to brake, you won't have any battery capacity left to store the energy of braking. An now your hybrid momentarily becomes a normal car and uses only the wasteful friction brakes to stop the car. That wastes a LOT of energy. Way more than paying the conversion tax. This wouldn't happen if you tried to use up some of the battery energy while driving. So it's a matter of sacrificing a little efficiency in order to not waste a big gulp of energy. Besides, remember that the amount of conversion tax you pay increases with the amount of current in/out of the IMA. Well when using battery to maintain speed the current remains very low. And battery charging during driving is similar. So the "tax" (loses) are low too.
One more supporting point. When driving on battery only, you sometimes don't have to try and make it happen. The car will do it on its own. Honda seemingly has provided this as a benefit. The same can be said for the Prius. If it was a wasteful thing to do, Honda and Toyota probably would have not included it in the software algorithm. ...And I seem to notice better mileage when I've been able to do it more.
New topic: The time my headlights ran down the hybrid battery...
What you say sounds correct. What puzzles me is that while stopped in traffic in AUTOSTOP (engine not running) and no other accessories on except headlights, I watched my IMA battery display slowly deplete down to zero over the course of about an hour. At that point the car came out of AUTOSTOP and stayed that way until I was able to drive and charge up the battery again. So now I'm confused as to what discharged my 100V battery down to zero. Is there a converter to charge the 12V battery from the 100V battery? What else would stop the 12V battery from running down during AUTOSTOP?
Listening to the engine when driving on battery only would suggest that the fuel injectors are not entirely shutoff. You can still hear combustion. The car sounds the same as when idling. Compare the sound when driving on battery to the sound when the car is in AUTOSTOP but still moving - it's very different. In AUTOSTOP you can hear the gas engine has turned off.
Another experiment: While driving down a long hill in battery mode only, I listened to the engine (and still heard and felt it idling). I was going about 40MPH. And then I turned off the ignition with the key while still movng and with the car still in the drive gear. Then the sound was VERY different. You could no longer hear and feel the gas engine idling and could tell it was really off.
Another experiment: While driving down a long hill in battery mode only, I listened to the engine (and still heard and felt it idling). I was going about 40MPH. And then I turned off the ignition with the key while still movng and with the car still in the drive gear. Then the sound was VERY different. You could no longer hear and feel the gas engine idling and could tell it was really off. "
I suspect that if someone hooked up a scanguage II and programmed it correctly, the fuel cut-off (or lack thereof) would be obvious. I know that my FEH cuts off fuel when above a certain state of charge and going downhill, for example.
However, I think that at some point, you just have to let the car's electronics manage things. Trying to make sure that when you brake, you always have someplace for the energy to go? Wow! Good point but that's further than even I want to take things! Good catch though.
Running on the battery alone is not a "feature" I would think Honda provided as a benefit. I think it is more likely a loophole in their hybrid control algorithm. If it were a "feature" I think they would advertise it as such.
Ideally, you want the electric motor to run where it adds the most value, and that is when there is a need for high torque, i.e. acceleration. Any other use is less efficient, except for maybe the case that you pointed out. I would love to see some equations to prove that but agree, you might be right. The most efficient condition would be when the car is traveling at a constant velocity, and the battery is fully charged.
I think I'll try something. Find a nice flat stretch of highway. When I start, the electric motor is used to aid acceleration. Once I reach cruise velocity, the battery starts to recharge. Now, based on your theory, the battery will charge fully, leaving no place to put the energy gathered by regenerative braking when I stop. If the algorithm is smart, it would always leave a some battery capacity for this energy recovery. Or would that be the smartest thing to do?
I wouldn't be suprised either way because, it seems to me that it depends on how you want to hedge you bet. If the car's computer knew that you where approaching a long downhill run, it would not bother recharging the battery with the ICE at all but simply wait until you start to go downhill. Now if the car's computer knew that you where approaching a long climb through the mountains, it would go ahead and charge the battery to peak capacity while it could. Since the car cannot possibly know what's ahead, I think the safest thing to do is to top off the battery. So I think you are right.
"New topic: The time my headlights ran down the hybrid battery..."
I know that the traction motor is used to charge both batteries. There is no seperate alternator on this car. Now with your headlights on, you would be depleting the 12V accessory battery under the hood. Perphaps the computer sensed this drain, and directed the ICE to start, charging the 12V battery. But that doesn't explain the graphics showing you a depleting traction battery. Hmm... I'll have to look into this question a bit more throughly and get back to you...
I can agree with you based on what your senses tell you is going on under the hood, or I can agree with the manufacturer.
I think I'll go with the manufacturer on this one spunjurno! With all due respect, I think the engineers who built the thing can give us a more accurate description of what is going on.
If you are correct, that would mean that Honda is, well, just plain lying about the product. What would be the point of that?
Fact is, when you turn the key to the OFF position, you are doing alot. You are shutting off power to the electrical motor used for steering assist, you are shutting down the electric fuel pump, inverters, panel electronics, etc., all of which contribute to the sound you hear in the car. The difference is more than you think.
If you want to prove your theory, come up with some way to measure the pressure of the exhaust at the tailpipe. Maybe a small trapped door that will open with the pressure of combustion while the engine is running, and stay closed when it is not. Perhaps a small remote camera strategically located can record the events. The valves stay closed when the engine is shutoff so there should be no exhaust pressure,... well..., according to the manufacturer! :-)
Well certainly you can't go too horribly wrong with that strategy since the engineers did a pretty good job designing this car. But until engineers are able to come up with an electronic clairvoyance feature, then there will always be room for the driver to improve performance by intervening. Naturally, the car has no idea whether you're at a stop sign and about to climb a steep hill, or whether you're about to go down a steep hill with a stop sign at the bottom. In the first scenario you would want the battery charged as much as possible. But in the second scenario you want it sufficiently discharged to accept all the energy you're about to put in. (I think I might be echoing what you already said.) Since the car doesn't know, it tries to compromise a little so as to be acceptable for either case, which also makes it less than ideal for both cases. That's where the smart driver comes in, who has the ability to properly anticipate the upcoming situation and better adjust for it. And improve mileage as a result.
"...Running on the battery alone is not a "feature" I would think Honda provided as a benefit. I think it is more likely a loophole in their hybrid control algorithm. If it were a "feature" I think they would advertise it as such..."
Well I know Toyota advertises that the Prius does it. It seems they think this helps the overall mileage. If follows that the competitor would have also wanted to design in a similar feature.
"...Now, based on your theory, the battery will charge fully, leaving no place to put the energy gathered by regenerative braking when I stop..."
No, not really. I didn't mean to imply that it doesn't leave ANY room left. But it doesn't leave much! Mine often continues to charge off and on until NEAR full charge, according to the display. It leaves very little room left for certain situations, like the case I described in post #56 on this board.
"...I know that the traction motor is used to charge both batteries. There is no separate alternator on this car..."
Right. But I wonder if the car maybe has a simple DC to DC converter to help recharge the 12V battery with the hybrid battery under such conditions. That would explain the discharge that I saw.
Well, not really lying. Perhaps they shutdown MOST of the fuel injectors and only leave on enough to be able to continue to idle. Or maybe they drastically limit the fuel to the injectors so that it burns very little fuel while idling. In order to simplify the point, the manufacturer might just say that they shutoff the fuel and consider the difference to be splitting hairs.
Maybe what I'll do to prove this to myself is wait for cool weather when you can see condensation in the tailpipe exhaust. I can either try to see the exhaust in my sideview mirror (or add a second strategically placed mirror) or have someone follow behind to see if it stops coming out the tailpipe when I idle.
I would agree that that might be a possibility if it were not for the context in which this information is presented. In the animation I presented earlier, Honda also says that in this mode, the engine's valves remain closed and it's cylinders sealed, to avoid pumping losses. You can't do that if the combustion process is still active,... even just a little bit. So taken as a whole, I would still bet that Honda's description of their engine operation is accurate.
Here is the animation again. I can find many other examples stating the same:
http://www.youtube.com/watch?v=xmDkc8SEvwc&feature=related
Yes, you did but that's ok!
"Well I know Toyota advertises that the Prius does it. It seems they think this helps the overall mileage. If follows that the competitor would have also wanted to design in a similar feature. "
I'm not sure that Toyota thinks that this helps the overall mileage. I think that most people who buy hybrids think that the more it operates like a "real" electric vehicle, the better. So it might help sales. As a "feature", it would allow the driver to implement his or her own "clairvoyance feature" as you suggest, but somehow I doubt if Toyota predicted that people would try and operate the car in this manner. (Only techo-geeks like you and me reverse engineer things like this!)
I've never owned a Prius but I have rented them while traveling or just for fun on many occasions. The only time that I have seen a Prius operate on battery alone was when starting off or going really slow. I think I got a 2006-2009 Prius up to about 18 or 20mph before the ICE came on if you accelerate real gently. Never seen electric only operation any other time.
Well, I hear that you can't spell "geek" without a double E ! ;-)
It is not really possible to compare the Toyota HSD with the Honda IMA. The Toyota system is designed such that the battery can drive the transmission without the engine turning. With the Honda, the engine is always turning. Completely different technology and design philosophy.
The Ford system is similar to Toyota; it can run the vehicle by electric alone at speeds up to 40 MPH. After that, the engine is turning, even if it is not using any gas.
The bottom line is that they're both hybrids Steve. The engineering details don't change the fact that they were both designed with the same purpose in mind. I assure you they can be compared.
Let's see:
The 2010 Prius has a EPA mileage rating of 51/48 while the 2010 Honda Insight has a EPA mileage rating of 40/43.
See? I just did it myself! :-)
My Insight displays its overall miles per gallon on the dash as soon as I turn the key in the ignition: 46.8 MPG
Either way, the 40/43 numbers seem off to me.
It's astonishing to me that the EPA (a government agency) could have possibly made a mistake.
I have rented a Prius for as long as a week and averaged about 46 MPG. Not sure why the EPA estimate seem low for the Insight. I believe their test procedures are the same for all vehicles, but the hybrids have different modes that they can be put in. They never mention what the mode the hybrid vehicles were in during the testing.
I read somewhere that their tests require that no special mode be engaged. Don't know if this is true. If it is, then ECO mode, Sport mode or EV mode would not be engaged on Prius or Insight.
Perhaps you could take your Insight out of ECO mode for a week and see if you get results that are closer to the EPA's results. Let us know your findings.
They cannot be compared in terms of the design. It takes a bit of study about how they were engineered. There were some statements being made that did not match the engineering.
One can compare mileage if you like, but that does not change the way the two system achieve that MPG - which is totally different. Yes, they both have batteries and electric motors, but they are used in radically different fashion. If you are not interested in the technical details, that is OK by me, but some people are interested...
As a side note, I have been amused by the dialog between you and spunjorno. You seemed spot on in your technical analysis in your initial response about pure electric use to get highest mileage in the insight, but his empirical approach delivers better milage. I tried to test using assist more to get more mpgs, but found I got much less. The reason was I had to use more throttle to get more boost. Following his suggestions, most of which I actually learned from the "Shell answer man" in the 60's, gives the best mileage regardless of vehicle. The advantage the Honda has is it's coach shows instantaneous mileage vs avg very clearly so you can set easy to monitor goals.
My note is that it really makes a difference driving 50-55 as opposed to 65-70. Economy drops from 57mpg to 46mpg.
I changed wheels and tires about 2000 miles ago to lighter alloy wheels by konig and put the bridgestone ecopia 422 tires on. Now I am getting 41.5 overall. On one mostly freeway trip to Vegas I got it up to 46.5 mpg. So unlike US brands (GMC) I think Honda really states the correct MPG's.
Great lower cost alternate to Prius, funner to drive, lighter, looks better, more front legroom (No weird Middle Console thing). But seats could be better quality.
Just like you, I had changed out the stock steelies to a set of '05 SI alloys and am wondering if in fact my mpg's improved with that swap? I don't keep detailed mileage records so have no idea if this could be true...hopefully it has helped. The highway mileage ain't to bad but my city driving has been always around 30 from my quick computations...in specs to be sure but nothing to write home about but not worth it to trade for a few more mpg's.
The Sandman :sick: :shades:
2023 Hyundai Kona Limited AWD (wife) / 2015 Golf TSI (me) / 2019 Chevrolet Cruze Premier RS (daughter #1) / 2020 Hyundai Accent SE (daughter #2) / 2023 Subaru Impreza Base (son)
The Sandman :sick: :shades:
2023 Hyundai Kona Limited AWD (wife) / 2015 Golf TSI (me) / 2019 Chevrolet Cruze Premier RS (daughter #1) / 2020 Hyundai Accent SE (daughter #2) / 2023 Subaru Impreza Base (son)
The Sandman :sick: :shades:
2023 Hyundai Kona Limited AWD (wife) / 2015 Golf TSI (me) / 2019 Chevrolet Cruze Premier RS (daughter #1) / 2020 Hyundai Accent SE (daughter #2) / 2023 Subaru Impreza Base (son)
I got a new 2012 Insight in Nov. 2011 with now about 2000 miles. I drive very conservatively, that is 55 mph in 55 zones & 60-65 on highhway. I try to keep my RPM under 2000, mostly stays around 1500 where it's flat. The car gets good mileage at about 50 mpg doing the "real"math with Excel after fill ups.(display says 52 mpg).
As you mention, keep the green light on, use the eco mode (never driven the car without it) and avoid sudden acceleration.
You really should get more than 33 mpg.
Good luck.
P.S. I did notice I loose mileage when it's get really cold, like 20 F.
- Ease off the gas and do not try to go 0-60 fast, but rather accelerate slowly.
- If you are cruising, get the feeling for the accelerator, so you are in the right place for your speed. It is a bit tricky, but doable: You need to decelerate a little, so your car stops accelerating and is just barely keeping the speed you are at. It is easy to give your engine more gas than it needs.
- Some people recommend accelerating past the speed at which you want to go, and letting go of the gas a bit so the car slows down very slightly, then accelerating again when the speed goes a few miles/hour under the speed you want to go at.
- Let your batteries charge when breaking, break early and stop slowly.
- The engine takes a while before it "loosens" to its maximum efficiency, so wait until you are past the first 10-12,000 miles to get the best mpg.
Finally, if you are commuting a short distance, don't worry, the best way to save gas is by not using it. In any case, with your hybrid you should be getting the best mpg for your driving style, whichever it may be, the key is adapting your style to the best mpg you can get.
I noted that "cinny 17" did not acknowledged any of the replies, I must be old fashioned I guess......
I think if you just bought the car you will definitely get less mpgs than if you let it run for about 10 to 15,000 miles, which is when people seem to start getting the best mileage. I have been able to get 50+mpg for the time it takes to re-fill the tank (with a winter average of about 40mpg and a summer average of about 48-50mpg), it is very hard for me to judge though because the landscape we normally drive through is somewhat rough. On a flat surface, I do get about 50-60mpg at about 50-60, in slower speeds and without acceleration, but just maintaining speed, I can get up to 100mpg, especially around 30-35 m/h. I will try without the econ, though when stopping you need the engine to go off, so maybe disengage it for highways? I hope it works better. Thank you!
I posted the consumer review for this vehicle shortly after I purchased in Nov 11. Since then, I can honestly say I have only grown fonder of this vehicle. After experimenting with different driving styles and techniques I have now increased my per tank average (calculated by fillup) to 52 mpg. I consistently average 65 mpg (MID indicated) on my mostly highway commute. Initially I kept my speed around 58 to 60 mph but now I am able to achieve the same at 65 mph. I attribute some of this to warmer weather, more miles on the vehicle and now running synthetic after 1st oil change at 7800 miles. Best calculated tank was 56.7 mpg for 370 miles. I have found that this car doesn't necessarily have to be driven slow but best mpg seems to be at 2000 to 2200 rpm, which for me is 65mph, above that it drops substantially.
The car has 34529 miles. The total overall gas mileage over that time is 52.7 MPG.
My best and worst tanks were: 58.7 MPG and 45.9 MPG.
I think that they should re-evaluate how they approximate the MPGs when they test hybrids. This one is stated to be 44, but I've never been able to get it that low. I know many Prius owners who have said the same thing.
They say, "your mileage may vary". But on other cars I've owned (that were NOT hybrids) my average was always within a couple MPGs higher or lower than the stated figure. This one is WAAAAY off. The test must unfairly punish hybrids in general.
I had owned a 2000 Honda Insight that I bought used (had 11,000 miles on it w/ 42.1 mpg for life). I put another 222,000 miles on it and ended with 58.0 mpg for life. So, I have some experience driving the Honda Hybrid, which may account for my being able to tolerate the GREEN indicator in the new one.
My first Honda was a 600 Sedan, then 600 Hadtchback all the way back to 1970. I got 42 mpg on my best trip, even then. Bought a new Civic CVCC in 1978, have owned a couple more Civic and even an Accord. Have never gotten below 30 mpg in any Honda that I owned, in all those years the US Car Makers said they couldn't do it.
I would have loved to own one of the Smart cars with the diesel engine when it was 70 mpg, but not now. Being single, the two-seater never caused me a problem. It hauled my skis and dog kennel. The 5 seater model feels heavier, especially when at a stop light that starts out going up hill!
BTW, I run my A/C at 78 degrees in the car. Sometimes, in the Texas heat, I have to lower it to 74, because the sun just broils you coming in the window. Have not figured out how to make the engine start again when in Auto Stop (I know, take your foot off the brake, but when you're stopped, that is dangerous). Never had a problem in the old Insight Manual Transmission. If someone else was in the car, I could pop it into first and the engine would engage so the A/C would cool them off.
Have always loved the Honda quality. Impressed when 4 of us owned the Honda 600 models, and if one person's clutch went at 35,000 miles, then we all knew ours would go about the same time. When a timing chain (remember those) went at 60,000 miles for a friend, mine went at 60,055. That is truly quality engineering.
Only had my 2010 Insight two months, so still getting used to it. But I'm happy so far!
Remember, you have two trip odometers (A & . I traditionally reset 'A' every time I fill up so that I can see the (car's computer calculated, but not very accurate) mileage of every tank. I don't reset the 'B' mileage. So on my car, the 'B' mileage is (almost) the car computer calculated lifetime average - almost, because I reset it by accident once early on.