[Mike Dabrowski 2000]

I think that if Honda wanted to, they could make our Insights, with minor re-engineering into a 100MPG car.
Think back to the first time you took a ride in your new 5 speed Insight.
One of the things that surprised me was how no new skills were needed to drive the car.How smooth the transition was. It also disappointed me, I wanted to turn on the electric when I wanted to, not after mashing down on the gas first.
Here I was driving a state of the art Hybrid car. It had a 1 liter super efficient gas motor, that could cruise at a constant 60 MPH with a fuel economy of 60+ mpg , with 100+ mpg possible when drafting, tailwinds and coasting all contribute to the mileage.
Use a heavy foot, and don’t pull back when your target speed is reached to feather the gas pedal, and you may drop to <50 mpg on the same route.
I immediately thought to my self where is the IMA control mode button.

We are basically unable to control the time of activation or torque contribution of the electric part of the IMA, without first causing the gas engine to try to respond to the request for more power. This causes us to sacrifice gas whenever more power is need to crest the hill, or pass a car, when in fact the same acceleration could have been produced by the electric power plant that may be fully charged and perfectly able to give us the gentle torque increase that we are asking for without changing the MPG of the gas engine at all.
What if the throttle worked in a reverse mode. In this mode, when the throttle is pressed down to ask for more power the electric assist is the first to respond, not the gas engine. Press down further on the throttle, the gas engine, which was sitting at a constant 100 MPG or other high MPG throttle position, powers up to meet the request for high power. The engine throttle control would lag the electric instead of leading it. The control program would auto feather the assist and gas to try for nearly constant lean burn.
Mostly a software change, no new controls. Maybe bigger batterys maybe not?


:wink:

 

[figgy]

I think you are totally right.

There are numerous times when a little bit of extra oomph is all that is needed, yet in order to get that you have to press on the gas and see lean burn stop. Then you have to back off more than you want and fiddle to get it going again. All that would have been avoided if you had been able to just blip a little electric assist and then recharge later while still in lean burn.

If someone could come up with a little button or something that one could activate to blip on the IMA without adding anymore gas, that would be ideal.

It is weird, because while lean burn is there, it requires a lot of fiddling to keep it goint. One would think that they could have put in a 'lean burn cruise control' in the software to do exactly what you are asking.

To me the simplest solutoin to get the stock car to do it would be to leave everything as it is, but have a 3rd control that just tells the IMA motor to engage if it is safe and possible. I don't know how to make that, but that would be great to have and certainly allow better mpg.

 

[Guest]

Ah! Looking through the other end of the telescope, eh?

Very ingenious reasoning. It does appear to be a likely mod with the results you state.

Perhaps I'm giving way too much credit to Honda engineers by assuming they already conceived of such an approach in the very early design stages and decided against it. In all likelihood it was probably a performance trade-off issue regarding recharging the batteries, though I'm not really clear as to why this would occur. Honda sure as hell won't be forthcoming as to why or why not.

This seems like an excellent concept. It would appear the only way to find the answer is to actually experiment - to do it!

Now, as with all great ideas, the question is... who's qualified and willing to put the bell on the cat?

 

[Guest]

Hi Guys:

___The AH uses IMA in just this fashion to widen the VCM window so that she will continue to run while under the ECO mode of operation.

___In the case of the Insight, there is no free lunch as the conversion from mechanical to electrical to mechanical is not free other then during regen. If our packs were hit for every small change, I can bet there would be a lot more guys screaming of recals, and IMA lights lit up, etc … If we had larger and more capable packs, maybe there would be something to this but charging that pack with all of these small hits is a drag no matter how it is done.

___I guess I just accept that our little beauties can achieve 100 + mpg now with very careful stewardship and that there is nothing else in the world that comes close sans a VW Lupo and all the baggage that comes with owning something that poorly designed.

___Good Luck

___Wayne R. Gerdes
___Hunt Club Farms Landscaping Ltd.
___[email:261xyxd2][email protected][/email:261xyxd2]

 

[figgy]

Until the computer is smart enough to see the road and traffic ahead, I would bet that the human operator with his little IMA button would be able to get better mpg by using it when appropriate and not using it when not appropriate.

The computer might waste energy by over-use, but the human would not have to do that - unless by choice.

If the human has driven the road or sees the road and traffic ahead, the human will know when it makes sense to use the IMA boost button and when not to do so, thereby avoiding the inefficiencies and waste of the computer overusing it.

For example, if you have a trip where there are undulating hills followed by a big downhill, you KNOW that you wil have plenty of energy to capture at the end of the undulating hills. Therefore, you will use you IMA boost button a lot on the undulating hills and get crazy good mpg vs. the stock system because that energy will all come back when you go down the steep hill.

That's a simple example. The computer won't know that, but you will know it. It will be better mpg. It will use battery more.

If someone comes up with this mod, I'll by happy to try it out.

In the simple 'reverse priority throttle' you definitely would run the risk of too much draining of the pack. I think the mod should be a secondary and parallel control system so that you only use it when you want, and otherwise it runs as stock system today.

 

[b1shmu63]

Xcel is certainly the mileage king, and he does this by using the pack as little as possible. Ultimately all energy comes from the gasoline and storing it in the batteries you lose energy. Braking recharging is already maximised.

The idea would make a lot of sense for a plug in hybrid, or a hybrid with solar assist.

However, I'm prepared to gladly eat my hat (figuratively) if someone can show me a modification that works.

If one knew that they were about to go down a long hill and had a full IMA charge, I agree that using some of the battery power to gain mileage ahead of the event would make sense. On small hills speed modulation is probably more efficient.

 

[Mike Dabrowski 2000]

The hyper milers rarely use the IMA, because the throttle priority is gas engine based, and by the time you get to the assist mode, it is too late, the MPG has dropped out of lean burn.
Yet they have learned to achieve great MPG despite the limited use of the IMA.
Although the present battery pack capacity is limited, the pulse mode of using the IMA would be ideal for a manual IMA, as it would give the electric torque with no decrease in MPG.
One would with on demand regen, be able to force charge at the maximum rate on each down hill, and stop charge when on straight ground.
One would find the best way to maintain battery SOC, and how to use the IMA to best advantage, driving it to achieve the best compromise of SOC and MPG. Hell people can get 100 mpg already, I have no doubt we would figure out how to use this to a MPG advantage.

The whole cargo box area is available for a bigger battery pack. Maybe the batteries that Clett found could be used.
http://www.dpreview.com/news/0503/05032 ... inbatt.asp
Battery replacement:
With a little work, we can measure and understood the temperature and voltage swings that the present battery presents to the BCM. The serial com seems to difficult to crack, but my solution does not need to fool with that.

We know that a current sensor tells the BCM how much charge and discharge the battery has been exposed to for SOC determination.
We also know that the subpack temps and voltage are used to determine SOC limits.
Could we monitor the true current drain and charge of the larger pack, monitor the new subpack temperatures and feed simulated temp and current signals to the BCM to fool it into thinking it was charging a smaller pack?
Simulating the pack current and the temperature signals would allow full safety for the new pack with temps and other limits being monitored for the operating parameters of the actual pack be it NMH or Lithium by the new external microcontroller based battery controller, that would then simulate the existing BCM inputs to show proper SOC on the guage.

It would be some work designing and building the circuit, but may be a better alternative than just changing out the battery with a the same capacity one when the eventual dreaded IMA battery failure finally happens. It would give us more options.
It could work.

:wink:

 

[b1shmu63]

Mike, I suspect that the current is sensed using Hall effect sensors of the like. This is as opposed to using a dropping resistance and measuring voltage. State of charge is based on the assumption that the pack is in good condition and is capable of holding a designed charge. If a second pack with identical specifications is connected to the IMA the current should split and the control circuitry accurately determine the state of charge for both packs. The trouble is if the un monitored pack goes bad things could really heat up, if you know what I mean.

Such a setup would be suitable for short term tests of an experimental system using a second hand pack.

Alternately the sensors could be desensitized. You would still run a risk of failure if the packs were in parrallel. This would work if the battery was a single series connected pack of a larger ampereage capacity. Unfortunately you would probably be using a different technology such as lithium and would have to examine their charging characteristics to see if they were similar to the nickel metal hydride cells.

 

[Mike Dabrowski 2000]

I will not get too far ahead of myself and try to anticipate the issues involved with adding a bigger battery. I believe it is a solvable problem, and it is not clear to me that a bigger pack would be needed, but it will be phase 2 of the project.
The first priority is to understand all of the signals passing between the ECM and MCM , and to substitute a manual PWM signal for the comand power signal and see what codes are generated. Yves is building up a PWM circuit as I write this, and hopefully will have a chance to try it out within the next week or so.
:wink:

 

[Armin]

I like it!

I was too busy to read the forum for a few days and then there is this highly interesting discussion!

I Really like Mikes idea of an add-on larger battery pack! Especially since we could add grid-charging at the same time.

Over the past few days, it has occured to me how beneficial grid charging could be: Usually, I start in the morning with an SoC around 17 or so. Driving up and down and stop and going through lights and onto highways drops it to <15, so usually force-charging starts right when I'm finally on the highway. This keeps mpg to around 70 for most of the highway leg until the battery is full, force-charging stops and I get 80+ mpg.

Just imagine: If I could grid-charge and store enough energy to cover the first few miles of assist, I bet I could get at least 85 mpg the entire 30 miles of highway! In the summer this would probably go up to 100 as Mike suggested.

 

[Mike Dabrowski 2000]

As some of you may have read in the modifications forum, Yves has made the first sucessful test of the Manual IMA control system MIMA. The results are so promising and point to a simple control circuit that I will design and build next week. I hope to have the fully functional PIC micro controller based prototypes of the mod kits ready for yves and I by next weekend.
Then we can really see how much difference in MPG this can make, and how the battery responds.
Probably best to move this discussion to the
Hybrid controls and the MIMA project thread on the mods forum. I will post results as I progress there.

 

[Mike Dabrowski 2000]

It does :wink:
The only two Insights with a working form of MIMA are acheiving 15-25% better milage using MIMA than with it turned off(hard to do)
:wink:

 

[trunkout]

What if the throttle worked in a reverse mode. In this mode, when the throttle is pressed down to ask for more power the electric assist is the first to respond, not the gas engine.
:wink:

hrmm.....like a Prius.....

 

[nemystic]

I’d been holding off starting a new topic about “Battery anxiety and the MIMA modification” until experimenting with a forced negative recal, to determine if my indicated SoC was reasonably accurate or not.

So far, after having the MIMA_L prototype for a month, Sputnik has had only one negative recal, which occurred after a 10 mile climb on the Tour de Sol rally event in mid May.

Until today, I’ve started and ended each commute with a > 80% indicated state of charge. Today, the final indicated SoC was approximately 70%, with a 98.4 mpg round trip fuel efficiency despite some adverse travel conditions.

In addition to enabling me to control the SoC and thereby perhaps to actually prolong the life of the battery pack, the MIMA modification (manual mode) with practice, can be used as a “reverse accelerator priority” device, and from experience, I would say that is it’s mode of greatest utility.

After the novelty of having a “turbo boost” button at your fingertips wears off, you’ll hopefully come to appreciate that: what is taken from the relatively small battery pack must be restored, and preferably in an efficient and non-destructive manner.

To use a financial analogy, if you pay your credit card bill on time, there is no interest charge.

Repeating a disclaimer for those who may not have seen all of the MIMA related topics and messages; I believe this modification adds the most value in moderately hilly terrain, with diminishing returns in the mountainous or flat terrains.

Despite having minimalist tendencies, for me, it’s now difficult to imagine how we ever lived without Xerox machines, personal computers, cell phones, and the MIMA modification.

 

[Mike Dabrowski 2000]

I made a familiar 50 mile run yesterday, but this time I used AUTOMIMA for almost the whole trip. The trip is over a rural secondary highway with the typical rolling hills of New England. I have reached a high for this trip several years ago at 84MPG, with very slow speeds, and very careful starts, and since then have averaged about 65MPG for the trip.
With out any of the mileage tricks, I achived 84 MPG yesterday. My speed was at or exceeding the 45 MPH average speed limit for the road. By careful setting of the assist and regen thresholds, I was able to keep the charge in the 50-70% range for much of the trip. The magnify factor was a moderate 2X. The AUTOMIMA setpoints had about a 25-50 MPG deadband between the assist and regen setpoints. To keep the system from not activating either regen or assist, I had to keep the throttle steady at about 100MPG. Come to a hill, and give a slight throttle increase to about 75 MPG, and full assist was there to get me up the hill, come over the other side, back off the throttle to 150 MPG, and I would get full regen, hold throttle at about 130MPG (not easy), and the regen can me modulated between 0 and max with the throttle.
Conclusion. AUTOMIMA use with good setpoints, achives the electric priority gains that I had predicted.
Can't wait for Rick to make his 500 mile trip home today, and see what he can do with this new hypermiler tool. :lol: