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I knock my 6 speed car in neutral pretty regularly on some longer down hill grades. When this happens all charging stops. The car will start charging again when I put it back into gear. Same happens no matter if I have the clutch in or out, no charging unless the car is in gear.
 

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Discussion Starter #82 (Edited)
Again you have to be careful not to be lead astray by the OEM assist and regen bars ;)
Like the SOC segments they are only a vague indication/representation of what's happening.

If for instance your car has a max permitted assist power level of 13kw, then when the car is showing all the asist bars you will be getting ~13kw.
However if your car battery is restricted to say 7kw, then when the car is showing all the assist bars you are only getting 7kw.
Logically you would think the gauge is a fixed scale and it would show less bars for the 7kw versus the 13kw, but it isn't and doesn't.

In simple terms it re-scales itself over the long term to the maximum power allowed. This also avoids concerns being raised by owners.
If the assist/regen bars scale was fixed and slowly showed less and less bars as you battery aged, dealers would be inundated.

The above also applies for regen.

The car will probably also do hidden charging in neutral that is not indicated on the dashboard
The other IMA cars do this in response to low soc levels. I will confirm this when my inline wireless meter arrives.

Whatever we do to stop assist or regen to protect a Lithium pack has to be 100% reliable.
So pressing the clutch (faking the switch) etc will have to be tested with instrumentation in place to determine how effective it is.

I have posted a wanted ad on the forum as i'm looking for the IMA pack mounting bars and cover (marked in orange) if a UK owner has a spare set.
All donations gratefully received. :p

62591


I think my plan going forward if the car accepts the higher voltage will be to do two power runs next week on the same dyno I used for the Nimh baseline.

The first power run will be with 48 cell Lithium configuration i'm currently testing.
We can see what if any difference that has made to the old NIMH figures.
I'm estimating about a 5hp gain and 10nm of extra torque.

The second run with the 72 cell configuration should give us about 17/18kw total.
So call that +5kw over the maximum standard 13kw maximum, about +7hp and probably another 15nm or so.

If and when we also introduce current hacking IMA power will probably rise to ~20kw+ with the 72 cell setup.
 

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It's clear that there cannot be any assistance when the clutch pedal is depressed or gearbox in neutral otherwise the engine would rev up.
There could be some charging which is not shown on the SOC display, but not much or it would pull down the engine revs. After a cold start my engine revs to 1500rpm for a few seconds before slowly dropping back to idle, which I assume is the IMA getting back the current it used starting the cold engine.
I'll check today how much clutch pedal movement is needed.
 

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Discussion Starter #84 (Edited)
The ECM adjusts the idle throttle to compensate for any regen loading when sat in neutral. Like a stationery generator when more load is applied.
It's quite capable of supporting several kw of regen load at idle. It depends on what part of the IMA is drawing power.

If the car is charging the IMA battery above a certain power level then it will show on the gauge as regen bars. Very low level charge does not.
If it's a cold frosty morning with heater blower, air con, lights etc etc at the max, then regen demand to feed the DC_DC could be 1kw or so.

The initial higher idle rpm after a cold start serves a dual purpose.
1) Increase potential regen for the things mentioned above. 2) Warm up the engine faster.

The actual amount of battery capacity used to start the engine with the IMA is microscopic. 30/40 amps for half a second or so.

Assist is commanded by the ECM based on a large number of variable factors including, engine load, throttle position, soc, elevation etc etc

We need to test whether faking the clutch switch cuts assist even when the car is in gear and the engine is working hard.

Pressing the actual clutch pedal unloads the engine and does not quite give us all the info we need.
It's helpful but we need a bit more in depth testing.

We need to be able to correctly cut all assist if a cell in our pack reaches the minimum.
The same applies in reverse with regen.
 

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Bad news. Its not just the clutch switches (if it is at all), its engine rpm change as well.
Neither assistance nor charging is cancelled until the clutch has disengaged enough for the engine rpm to change significantly. I've been up some moderatly steep hills with full assistance and coasting down others in 6th with 100% charging (by slight brake pedal movement).
So either the switches are not used, or the rpm change is a backup in case a switch fails, which seems plausible.
So you may need to use a MITM to intercept the ecm to IMA data - not easy and impossible until we have decoded the can ids and identified the relevant bytes.

Also, I think the SOC gauge is recalibrated on the fly, taking into account battery status, temperature etc. This is why it always shows 100% assistance or charging under all conditions.
 

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Discussion Starter #86 (Edited)
The early Insights did cut assist if you activated the clutch switch, Thanks for testing this.
Back to faking a battery temperature sensor or three then ;)

It's not a problem for now as I deliberately charged my LTO packs to about 75% SOC when I fitted them.
So they are operating happily in the small SOC window allowed by the stock system and not getting anywhere near the limits.

I'm just charging up my extra pack on the bench now to match the two in the car ready for some voltage hacking fun if it stops raining.
I have just modified my hacking device so I now have finer control over the parameters.
 

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Discussion Starter #88
Agreed. As a stop gap it will probably work but be annoying when the fan is running at warp 10.
But we do need a MITM to take proper control of Assist and Regen so that we can command or override it as we see fit.

Manual control has been a boon for enthusiasts in the other IMA cars as you can command assist or regen at any level for as long as your battery or licence can stand it!
It helps with instant performance and mpg challenges. A human can read the road/terrain ahead and adjust or optimise things accordingly. The car cannot..
 

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Discussion Starter #90
I have installed the extra 24 cell block in the car but not added it into the circuit yet.
I have been gathering some live data from the IMA to ensure my calculations etc are correct and checking the BMS.
I think one of the blocks has a bad BMS board so I will have to swap that out. :rolleyes:

I will add 12 cells ~30V at a time (Half a block) and test as we go.
12 Cells will take the voltage from the 114V now to 144V, the second 12 cells will up it to 174V. :eek:
 

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Update on the clutch switches.
I was on my way out with the dogs, doing 70mph up a steep stretch of the A1 near Alnwick which needs 100% assistance and full throttle to hold 70 in 6th - 2800rpm (speed does creep up slowly so not much in reserve)
I then moved the clutch pedal about an inch and it cancelled all assistance and felt like I'd touched the brakes.
However, I wasn't able to recreate the same effect at any speed on other lesser hills and level roads between 60 and 75 in 5th or 6th so maybe it was gradient related.
 

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Discussion Starter #92
Could you add a switch in parallel with your clutch switch and try pressing it at various times?
 

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Discussion Starter #93 (Edited)
Voltage Hack Stage 1 +30V in and car running with no errors.

The first half of the extra LTO Lithium block is now in and active.
The car is accepting the pack and started normally with no IMA errors.

62593


The actual pack voltage is now 144V, up 30V from the 114V it was before.
The car thinks it is about 115V. I need to check this with the HDS tomorrow to confirm my calculations.

No ign warning light, so the DC-DC is still working, so all good so far.
Test drive tomorrow. It's been another long dayyyyyyy where is the vino and my sofa.....


The car will run with the same current levels as before!

So for example 110v x 120A = ~13kw previously.
That's the absolute max Nimh OEM power with a new perfect, warm, fully charged battery. (Or the 48 Cell LTO pack!)

Now that becomes 140V x 120A = 16.8kw :devilish:

Tomorrow might be 170V x 120A = 20kw :ROFLMAO:
 

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Discussion Starter #95 (Edited)
I think you have a meltdown fire fetish ;)

Once the voltage hack is tested I'm going to take the packs and IPU out again and sort some better mounting arrangements.
Proof of concept or not the lack of an interior and the mess is annoying me already..
 

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Hopefully not, but it could be me who needs the firebrigade when I finish building my valve amp. It runs on 490v DC so maybe I should have a paramedic with a defibrillator on hand as well. Weather no use tomorrow for car jobs.
 

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Discussion Starter #97
I've been looking at the PEC 400V DC 125A IMA main fuse specs today. It looks quite rugged from the data which is just as well.

If we increase the current later in the quest for even more power there isn't a higher rated drop in replacement of the same size which is a shame.
We might have to put a link in its place and move the fuse to another more accessible point in the high power wiring.

Anyway I shall stick with that fuse until it blows. But I do need to get a couple of spares.

You can see from the info that it can stand 110% rated current (137A) for 4hrs!
It can also stand 250A for 5 seconds! That means if we wanted 150A it would probably stand that for a few minutes.
We won't be going that high but the fact it's comfortable on the ragged edge is good news.

62594
 

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Hi, is quite a bit of times I would like to buy a crz, I have reed the full thread, I saw your comment saying the mcm cut the power of the ima in relationship of the kms and year of the batteries, I also read is possible to reset that parameter, bu l didn’t understood how is possible to do it, I would like to do that work when I buy the car, and after install a lithium battery pack and well if possible uprgrade the % of the ima assistance ,

please keep doing what you doing because is very cool
 

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The fuse will stand a significant increase for long enough for the batteries to be discharged, during which time the current will be dropping. (same during charging) so I'd be surprised if it blew.
 
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