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Discussion Starter #1
Wow I know everyone is thinking another MIMA thread. Now that MIMA is getting more users I thought having a thread for the operation and performance would be worth it. I'll find my other post on performance and move it to this thread.
 

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Repost of first long MIMA drive 24 July

Well Insight 00 #4738 has MIMA-C Ser #001 installed. I drove up to CT and Mike guided me through the install. It was a lot of fun looking around in the battery compartment. We spent about a day and a half but a lot of the time was spent looking at a lot of Mikes other projects. He has a few more installs lined up and the others will probably be faster unless they do what I did (Mike whats that?). I think there are about 40 wire taps needed and by the end I was felling pretty confident in the sodering of the connections. Mike built my circuit board (actually he tested it for a week or so in his car) but with detailed instructions I think a novice could handle the install. The key would be to go slow and double check everything. (I had a few mistakes in the process like putting the diodes backwards, cutting the wrong wire etc) but Mike caught them as we checked the wiring). I think when the instructions are complete it will be step by step and thus if you go slow and are careful you will be able to do it. Mike is also planning to have several installation levels that will allow you to tackle the project in smaller chunks to build your confidence as well.

First Impressions:

1. Wow! Being able to tap the IMA for full assist or regen is pretty impressive. Reminds me of the time I drove Willie's little Red Rocket and felt the turbo kick in. It definitely adds to the fun to drive factor. I used full regen on several hills instead of the brakes and it does a pretty good stopping job. The assist or regen response is imediate with no delay or lag. This mode of operation is called the Auto-activate Mode. It allows temporary manual joystick control of Assist/Regeneration. This mode is activated by moving the joystick. After three seconds with no joystick activity (joystick back in the center), the system reverts back to standard Insight IMA mode, with background charging if needed. You can think of it as the manual override to the IMA logic. It allows you to do stuff like get full assist from the electric side even though you are not pressing the gas at all. In other words you are crusing along at 150 mpg in 5th gear and want to pass a car. No need to change the throttle position or downshift. Just hit the joystick and stay at 150 mpg and let the electric side provide the needed extra power. I think this is the mode I will use the most but only time will tell.

2. The next mode is Active MIMA Mode. Its esentially the same as the above allowing joystick control but the car does not return to the Insight IMA mode until you disable the Active MIMA mode using a push button switch. I can see using this mode when you don't want the parasitic background charging. I havn't really spent much time with this mode but intend to get some experience with it in the future.

3. The next mode is called MIMAAUTO Mode. Its kind of like an electric cruise control based upon the MAP signal. Basically if the mpg reading falls below a threshold that you set the IMA kicks in to meet the demad instead of the engine. If the MAP signal goes above the point that you set then the Regen kicks in to charge the battery. Its amazing to see what this can do for fuel economy. Mike and I went out on a test run and got 120+ mpg for over 10 miles but note that we had too high of an assist point so the battery was not staying completely charged. I plan to experiment with various set points but so far have only used the really high ones. This really has a lot of potential when working with a cruise control. I have a Roseta cuise control and when both it and MIMAAUTO are on they complement each other beautifully. For instance when the car slows to the min speed set on the cruise control the cruise control will increase the throttle position causing the vacuum to drop. Normally this would continue until the engine provided enough power to maintain the speed set. However with MIMA-C the dropping vacuum triggers MIMA which reacts much quicker than the engine and causes the IMA to start providing the additional power needed to maintain speed. As the speed increases the cruise control reduces throttle pressure causing the vacuum to increase thus dropping the need for assist. In other words this is a cruise control that combines both the speed and mpg set points!!!!!! (First time I ever tried one of those smile faces.

4. But wait there's more! Mike has a display that shows you the real current values flowing too and from the IMA. I think Honda used a random number generator on the assist and regen guages as they don't show things correctly. Mike uses 4 leds each representing a threshold of amperage. So you can get 1-4 green leds representing 12.5 amps each of assist or 1-4 red leds representing 25 amps of charging each.

5. He is a user of the system and is constantly trying to improve the controls and programing. As a early installation I have no worries about my system becoming obsolete because I can simply email Mike and tell him to send me the chip with the latest program and then my system will have the latest updates.

6. Mike is pursueing a lot of possibilities for our cars and I hope he does well with the sale of this system. Take a look at http://www.edrivesystems.com/. This is a plug in Prius option for around 10K. With MIMA-C and a home charging option I could see the Insight getting incredible mpg on commutes by using higher set points in the AutoMIMA mode and then get charged later or shift to auto-activate mode to let the engine do more charging. Mike is also looking at a more powerful battery install which would give us all more options when our OEM battery needs replacement and we are well beyond the 80K waranty.

7. Believe it or not I actually was speeding most of the way back to DC. Part of it was having fun with Auto-Activate mode and the other because I lost the fuse to my stereo amp and was getting tired and did not have my usual way of staying alert. Even at 70-75 mph I was getting segments near 100 mpg with MIMAAUTO mode. I would then shift to Auto-activate until I got the battery charged back up. I'll provide more mpg info once I get more testing on a route that I know the result ranges without MIMA.

Notes to Mike:

1. Is there a reason for the 3 sec delay in MIMA autoactivate mode between the no activity on the joystick and return to normal Insight IMA control? I found that sometimes I would use the joystick to slow but then if I tap the brakes I get no regen until the IMA logic takes back over after the 3 sec delay). If this was arbitrary then perhaps cut it to return as soon as the joystick returns to center. Can't see anyone letting go of the joystick and then needing it again in less than 3 seconds but perhaps others will have different feedback.

2. I am still getting used to the interface. I think I hit it sometimes unintentionally. Perhaps I should have used the trigger mount that you use but that is easy enough for me to change later. Anyway I had two times when the car did not start from autostop (I think it was because I bumped the joystick but will test some more). The first time I restarted with the key and the second I just used the joystick and the engine came to life. (I am guessing the 3 seconds also was the root of this but havn't tested the theory). (I assume the manual override of bumping the joystick disables autostart until the Insight IMA logic takes back over).

3. You were right on the new Prius using less modules and lower voltage battery. It uses a transformer to step the voltage up to 500V and the new batteries have a 35% increase in power density which give it the 2 sec faster 0-60 time.
_________________
Rick 00 #4738 Lmpg 90.2 @ 127K miles
 

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Discussion Starter #3
My second long trip with MIMA 28 July

This time I was going to try and get my typical commute in for comparison purposes. In other words try and give some info on mpg gains but the weather didn't cooperate as I had over 100 miles of driving in strong winds and rain due to thunderstorms in the area. The total trip mpg was 94.4 mpg which is very good considering the weather. I have had plenty of trips with better mpg but none in this kind of weather that I can think of. Additionally I am still learning how to use the system better and hope to improve more as time goes on. In my last run I mainly used the Autoactivate mode so in this one I wanted to get some experience in the other modes.

MIMA Active Mode: I spent probably an hour in this mode and learned the following.
1. I did not get any assist or regen unless I used the joystick which is what it is supposed to do.
2. The DC to DC converter continues to operate but the SOC does not decrease. (I am really beginning to wonder if recals experienced in 5sp's are because the DC to DC converter usage is not accounted for accurately. ) With Mikes set up I could turn off assist / regen with MIMA active mode. I know the DC to DC converter was on because my battery voltage was over 13 volts. The headlights, wipers, stereo, fans etc had to be using power but the SOC would stay constant. I did this for at least 30 minutes.) I intend to try this some more as it could explain a lot with regards to battery recalibrations. Also note that in Heavy MIMA usage I could use the whole range of the SOC. I could drop down to 1 or 2 bars on the battery and not see a recal. Normally if I drop the battery to less than 2/3rds a recal would follow. Anyway its something worth investigating.

AutoMIMA Mode: I played around with various set points but never really got the regen point where I wanted it. Mike told me the voltage changes are very small as you get on the edges of the signal so I believe that is my problem. He plans on changing the software so that the assist and regen points can have different multiply factors and also to allow for fine tunning the set points by toggling the point up or down a descrete value as opposed to setting a completely new point. I think either of these will allow better control of setting the point. In regards to performance it was impressive and worked just like I described in the thread above. This time however with different set points I was able to better manage the battery. In my first try I only had 6 bars showing on the battery when I inacted autoMima using. I averaged 120+ mpg for 30 miles before the last bar went out on the battery. (North of Fredricksburg to north of Richmond) Certainly the battery drop energy isn't accounted for in the mpg value but think of how this could be used in a plug in hybrid mode. Anyway I decided to adjust the regen point to a lower threshold. I also used manual regen to quickly push the battery back up to full. I then made a run of 110 miles at 108+ mpg before dropping to about 1/3 charge on the battery. (South of Petersburg to Durham) I found this impressive because I did not get a recal. My plan is to hook up a voltage meter so I can see the setpoints that are entered. I am guessing that a lower threshold for regen will keep the battery balanced overall and yield mpg around 104. Just a guess but it will be interesting to see if it is achieveable. I watched the OBDII scan tool (Autoxray 4000) and noted that the bigest way of noticing that AutoMIMA is on is that the engine load has a tighter range (lowers highs and higher lows). On my vacuum guage I could see as soon as the vacuum dropped to around 2 inches and the bar graph dropped to the 75-85 range I would see 1 red led on Mikes display representing somewhere between 1-15 amps. If the bar graph dropped to below 75 mpg then I would get 2 leds of assist. If it got all the way down to 50 mpg then you would see 4 leds with max assist (60 amps).
On the Honda charge and assist guage there seamed to be no logic as to what registers and what does not. The only consistent trait is that if you saw assist or regen on the honda display then you were definitely getting some assist or regen. The level made no sense however as 4 bars of regen on the guage could be anything from 1-4 leds on the display representing anything from 1-100 amps.

Have fun, RIck
 

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Hi Rick
Good idea, This will be the official MIMA users thread.
To bad about the rain, when will you be doing your next run to DC?

As I explained in the PM this morning, I suspect that you were not actually changing the regen setpoint when you thought you were. At a setpoint of 125MPG, and magnify of 2, you should have seen substantial regen when you had the MPG at 150MPG, with the setpoint at 100MPG, you should have seen full regen at 150MPG. This area of the map changes quite rapidly with engine load, and therefore it is important to set it only after holding the 125 MPG steady for 10 seconds or more to allow the map signal to settle to a fixed value.( not easy with your foot, but should be easy with your throttle control) The map can change several times faster than the MPG display, so if you try to set it as you cross the 125 MPG point, the actual map can be quite different than you think it is.
This is why the ability to jog the setpoint up or down will be so helpfull in the fine tuning of automima. We may find two setpoints that will work well for hypermilage automima, and then I can set those as the default for the system. We can call them the Rick Reese default setpoints.
Thanks for the feedback, Yves will be equipped by monday with MIMA_C # 002, so we can begin getting more of the much needed feedback to fine tune the software.
Have fun, drive with the wind at your back, and MIMA at your finger tips.
:wink:
 

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Rick Reece said:
MIMA Active Mode: I spent probably an hour in this mode and learned the following.
1. I did not get any assist or regen unless I used the joystick which is what it is supposed to do.
2. The DC to DC converter continues to operate but the SOC does not decrease. (I am really beginning to wonder if recals experienced in 5sp's are because the DC to DC converter usage is not accounted for accurately. ) With Mikes set up I could turn off assist / regen with MIMA active mode. I know the DC to DC converter was on because my battery voltage was over 13 volts. The headlights, wipers, stereo, fans etc had to be using power but the SOC would stay constant. I did this for at least 30 minutes.)
That's interesting. Do we know if the "demand" for power for the DC-DC is done via the same signal as the Assist/Regen that Mima takes over?

What I'm getting at, is that even with the accessories that you mention switched on, that's probably a 15 to 20A 12V load, which will be a 1.5 to 2A load on the NiMH battery. So, in half an hour, you should have noticed as much as 1/6th of the capacity used.

So either it is not noticed or not shown correctly by the display, as you said, or the drain is "automatically" matched by generator, so the NiMH battery isn't discharged.

Any ideas?
 

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Discussion Starter #6
Kalmar,

I agree that something didn't seem right. I plan to do more testing. I would not think that the signal would be the same as one supplies power to the motor and the other to the converter. I believe Mike is only tapping into the signal to supply the motor but Mike can clarify. Now keep in mind that in this mode I had esentially turned off the motor regen and assist. This means that the normal background charging that the IMA does was not present. But it could explain how the SOC meter gets out of touch with the actual battery SOC. The recal would then be triggered when a low voltage signal occured.

Mike,
I am sure you are right about not setting the regen correctly. I will take the instructions you sent and try today.

Have fun, Rick
 

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Kalmar& Rick
I think Kalmar is correct, the load is balanced with the generation, so no current is going into the battery or coming from it. I have left the MIMA in active mode during night driving with the lights on for nearly an hour and have seen the same thing as Rick, the battery SOC stays up.
( a good thing) Another reinforcement to this is an observation I have had with AC. I was stopped at a light with the engine at idle,(cannot produce much current) with the AC on. The MIMA ammeter which has a +- 1 amp dead band where no leds light, was flashing red, then green, then red, at about a 2-4 HZ rate all the while I was stopped, once I got the rpms up, both leds went out.
A look at the schematic shows that the DC/DC is on the motor/generator side of the SOC current sensor. This means that if the DC/DC was being supplied with just the correct current from the IMA charging system, to balance the load, that the SOC sensor would not see the current, it only would show when in autostop when there is no output fron the IMA , and the HV battery is suppling the Dc/DC current..
Thats probably why they have a separate MPI curent sensor.
More of the mysteries of the IMA are uncovered.
 

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Here's some additional observations for consideration with regard to the "mysteries" of the IMA and battery charging system.

I use a DVM to monitor the total system current. Consequently, the value indicated is precise, and presumably accurate.
(The values referenced below are in amps, which is the DVM indication / 2.)

The "background" system current seems to range from +2.5 amps to +4.5 amps. The value isn’t consistent, although changes don’t appear rapidly. However, I do see a relatively small increase as 12V powered accessories are turned on (headlights, vent fan, direction signals, interior fan). One time, at stop, I did a simple test and observed about a 0.5 amp increase when the power steering was engaged.
This would all seem to confirm that the indicated “background” system current (in the MIMA mode) is the DC/DC converter charging the 12V battery.
It's not clear to me whether:
1) the current (presumably from the IMA) to offset this background current doesn't show on the hall effect sensor voltage - indicated on the DVM;
2) the "background" current is relatively small, so it takes a long time to affect the SoC; or
3) the hall effect sensor, or the measuring instrument, or both have an offset error.

On a smooth surface road, it’s possible to move the joystick so that the indicated current is 0.0 amps. Presumably, this indicates that there’s just enough MIMA forced regen to offset the “background” system current. In future MIMA software releases, I believe it will be possible to set continuous regen levels. If I'd have the ability to set the regen to indicate an average of 0.0 amps system current for a long period on a flat road, it would be interesting to see if the SoC increased or remained the same.


I’ve had about 4 negative recalibrations since installing the MIMA modification. In each case, they occurred after long periods without a recal, and when the indicated SoC showed just below 50%. (I usually try to maintain between 75% and 100% indicated SoC.)

Although the recals occurred in each case when the batteries were a bit warm (approx. 100 deg. F) it would seem as though there may be a cumulative error that increases with the period between recals or IMA resets.
 

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Be careful of trusting your DVM. The regen on the insight is not a dc voltage, it can be a rather large sawtooth signal, the average value of which repersents the current in or out of the battery as sensed by the hall effect sensor.
http://pages.cthome.net/genesisone/max%20regen.jpg
The scope trace shows what the current looks like In the cars ammeter circuit, I am low pass filtering this signal in MIMA to get the average current, and I show virtually no current in or out of the battery, (+-1A deadband)when MIMA is active with no joystick motion. Your meter may or may not be able to properly average this complex waveform to yield the corrent average current. The analog meter I used in the past, also mechanically filtered the signal. I think your relaitive readings may be ok, but your static readings could have an offset based on how the meter converts the waveform to a reading.
:wink:
 

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Since I commuted by bike last Friday, I didn't have access to a scope to make regen measurements on Sputnik.

With 2 separate DVM's, both the DC and AC scale measurements of the "background" system current were virtually identical on each respective meter.
DC indication ranged from 2 to 4.5 amps.
AC indication was negligable.

(Since the signal is from a hall effect sensor, the actual measurements were on the voltage scales.)

When I forced regen to the point of a DC indication of system current at 0.0 amps, the engine RPMs dropped, indicating a loading condition on the motor/generator. The system current on the AC measurement scale was 0.

Although I wouldn't expect DVM's to interpret a sawtooth waveform at approximately 250 hz as a sine wave at 60 hz, I did notice a significant measurement on the AC scale at higher levels of assist and regen.

'Looks like more data may be needed to explain the offset.
 

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Yves and Louise spent the weekend camping in my back yard, as we installed his MIMA. He managed to bring a big two room tent, and all his camping gear. His Insight trailer is a perfect accessory for the car, as he has made it so it fits right into the shadow of the insights air stream.
The tent is big enough to theoretically park the Insight inside, and still have room to sleep.
MIMAc # 002 was installed sucessfully in Yves red rocket(he likes to go fast). The install went quickly ( 3 to 4 hrs)as Yves and I each worked on different parts of the harness. Yves also figured out that the rear cable could be fished through the rear of the seat area without as much disassembly as Rick or my install, so that saves some time. Yves had already installed a joystick on the rear of his shift console, so with only a small amount of drilling we were able to mount the MIMA control card in the same spot.
My plan of installing the first units close by has not worked out, as Rick and Yves are hundreds of miles from here, but They will both provide some valuable feedback so the system can be optimized, Yves will also begin working with the program, as he has an ICD2 and programming experience.
I will be putting up photos of both Rick's and Yves installations on my website.
Who will be next? Maybe JackMPG.
I also decided that I will fabricate a custom display of either style for all of the first installs, for no extra charge, as a bonus for the first brave people to MIMAfy their cars, I will also not charge any labor for my help with the install, so this is the time to get a ready built MIMA for the best price.
Who wants to be next?
I am working on the release form and install documentation today, so that I can begin mailing out systems to the people too far away for me to help with the install. Calpod, is ready to be the first to self install a system, and we hope to get the stuff out to him this week.
Another small step towards MIMAfying the Insight fleet.
 

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Hi Mike,

Thanks for the camping site, it was beautifull.
I now have MIMA: WOW!

It is real fun. I actually did not have time to try out the Auto Mima yet as I did not use it before getting home (wife was affaied that something could go wrong before we get back to the contry, we are too cautious) and I am in traffic going to work.

So today I used Mima alone. It is really fun, it can surely compare to the Prius EV mode. I made a run with my supervisor today in my workplace parking lot and he was really impressed. He already knew the car but it was "look, no feet" both for acceleration and braking (maybe 20PMH in second gear)

I will do more experimenting and will put all my effort possible to help out on the coding.

I can not say it enough: Thanks Mike

So I have the #45 Insight in Canada, the 1st Mima equiped in Canada and the second (maybe third counting your's Mike) in the world. Very Cool!!

I am very proud of my car. And most importantly of the Mima.
 

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Calpod said:
Mike,

I'm ready, just read at the bottom of my profile.
I can help if you need/want another set of hands.
 

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The observations I have is about Auto Mima.

a) I have used it in a way that the regen was greater in average than the assist: the result was soon to have a full battery

b) I have used it in a way that the assist was greater in average than the regen: the result was soon to have an empty battery

c) I have used Auto Mima so that my usual way of driving (fast) that has always got me an about half way charge battery: got me an almost full battery.

Now that shows more regen than I usually have, so that the battery is more charge, to my supprise, my MPG was higher than normal. I do not have numbers for now (about 0.4 L/100km diff) but I can imagine that even if I drive fast, the SOC being higher, the system keeps me in lean burn in a wider range of situations.

I have noticed that I got lean burn at 116 km/h while I do not get it above 100 km/h normally. Keep in mind that I have no special tires (no LRR) that are 185/60R14 which are harder on the MPG than the originals

I will need to do tests later
 

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New here.... What's MIMA?

Okay, first let me introduce myself... I've been lingering around here the last few weeks reading as much as I can before I purchase my used Insight (2001, 70k miles, accident at 60k, but doing fine). I live in Mid-Michigan, so I'm concerned about snow and cold temps. This coming school year, for the first time in my life, I will have a half-hour commute to and from work everyday. I'm looking forward to making some of these mods, but I am completely car-stupid, not to mention broke. My big goal with this car was going to be learning to change my own oil, but as I read on, I see I ought to have much bigger ambitions than that. I believe, however, that I will end up being on here a lot (although I do have a busy year coming up) and will be asking lots of questions and needing LOTS of help. I am vey serious about squeaking out the very best mpg this little beauty can muster. Anyway, that said, my question is:

What's MIMA?

Maybe someone will direct me to a different thread, I don't know, but everyone on this thread looked like they knew what they were talking about and are nice (a big help!), so I thought I'd try here. Hope to hear back from you guys.

Lindsay
 
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