HCH1 Inside the IPU and more power.

[retepsnikrep]

Having been delving around this a bit recently and studying the manual I think we might have another option for more power with a Lithium upgrade.

The HCH1 IMA current as we know can be increased tweaking a number of current sensors for an 18.5% increase. Matt says this works well on his car and he is using the stock 100A fuse.

However increased system voltage can also deliver more power without increasing current and abusing the 100A fuse.

The IMA power in Watts is simply Amps x Volts.

If the system voltage under load is 140V x 50A that gives 7.0kw
If the system voltage under load is 180V x 50A that gives 9.0kw

The HCH1 MCM detects the system voltage using the battery voltage tap inputs.
It does not appear to have a second voltage check from the IGBT/driver module like the G1 Insight does

Edit Looks like I was wrong about this.

The G1 Insight uses voltage taps for the BCM voltage detection, but this is compared with a special voltage check analog signal that the IGBT sends to the MCM. These two values are compared by the MCM, and so both had to be faked to enable a voltage hack mode in the G1 Insight. Quite difficult and a bit of a PITA.

With the HCH1 it appears only to have one voltage sensing system (via the taps), which is faked in my Lithium pack by the BCM fooler resistor matrix, and made adjustable with the addition of the pot on the + end to fake a lower system voltage if reqd.

I may simply be able to turn the detected system voltage up and down with the simple pot and the actual battery voltage will determine the IMA power. We already know the car tries to compensate for an apparently lower system voltage by increasing IMA current so we get a double bonus

Only a test will determine if some other voltage detection is being implemented but from study of the data and the IGBT data sheet etc I don't see anything. Fingers crossed!

PS I saw 90A briefly from my stock HCH1 setup today as battery temp was 25c or so. So I might simply fake the oem NTC battery thermistors for a static 30C battery temp to ensure the IMA will deliver full current with my Lithium setup. I need to take some measurements of their resistance at 25-30C or so.

[retepsnikrep]

Just looking at the temp sensor charcteristics they are given in the advanced diagnostics as 10k at 25C (77F) that sounds like a good number to start with so I will make a up another dummy temp sensor plug for my HCH1 Lithium set up with 3 x 10K resistors for the NTC sensors and 1 x 20R for the PTC strips. That should give optimum IMA temp current performance.

[retepsnikrep]

Further study of the HCH1 advanced diagnostics and manual indicates there is a voltage check between what the MCM detects via the voltage taps and what the IPU detects in the IGBT. Now there is no DAC VPIN in the IPU like in the G1 insight so a simple analog hack won't work as there is no line to tap into. The advanced diagnostics indicate a difference of more than 10V between the MCM and IPU voltage will trigger an error, this is the same as the G1 Insight.

The manual goes on about serial comms between the IPU and the MCM on the IPUA line. So the only place the voltage data can be is on this line perhaps in a packet of data with the IPU temp signal and fail flag data.

I feel another pic 12F683 interceptor project comming on to filter this data and pass thru lower voltage signals. I'l try and capture some basic data later today. It should be farily easy to see the voltage byte in any data, as when the car first turns on the bypass contactor operates and we should see a fast/steep rise in a value as the IPU capacitors charge up prior to the main contactor operating. If I measure the voltage before we start and once the charge cycle is complete it should allow us to establish a relationship between the serial data value and the IPU voltage.

[retepsnikrep]

Captured some data from the IGBT IPU powered up on the bench.

Quite a few packets being sent at what looks like 9600,8,N,1 but I also powered up the HV side of the IGBT and turned my 0-300V psu up and down while capturing the packets so should be able to work out which one is the voltage byte.

A123 Civic 012 - YouTube

[retepsnikrep]

OK here is a spreadsheet of some captured IPUA data.

The serial data is made up of 5 repeating packets of 6 bytes.
Each packet contains 4 data bytes and a header and chksum byte.

Can you spot a pattern or corelation between the voltages I was applying and the data.

Comments and assistance welcome.

[samwichse]

Man, those numbers are all over the place.

I can see a good correlation among your data in the 0-100v sheet. Starting at line 66 you can see all the data in the last four runs does the same approximate thing, but what that is, I'm at sea about.

Just looking at the 0-100v runs here:

The middle two bits don't seem to do anything related to voltage output. The numbers are different between the runs, but stay constant throughout... no idea what's up with that except that they give some kind of state? Except that first run, but it seems to be "flickering" I don't know if that's a bad connection, or what.

If it's 6 data bytes (byte 0 being the Id and byte 5 being the Chk), bytes 1 and 4 seem to be the entirety of the real data. Byte 4 seems to only toggle between 0 and 160 (0 and 10100000). The toggle seems to alternate with changes in the byte 1 value, I find this to be a pretty telling series (lines 67-71 in the second 0-100v run):

Byte 1		Byte4
00000000	10100000
10000001	00000000
10000010	10100000
00000011	00000000
10000100	10100000

Looks like byte 4 toggles its value between each incremental change of Byte 1. The first bit of byte 1 looks like it's lockstep with byte 4 here, but later you get this (shortened to unique values only):

Byte 1		Byte4
00000101	10100000
00000110	00000000
00000110	10100000
10000111	00000000
10000111	10100000
10001000	10100000 *Might there be a missed value here?*
00001001	00000000
00001001	10100000

[retepsnikrep]

I'll double check my data and capture some more later. Capturing data from the IGBT module on the bench might not work as most of the I/O is not connected and perhaps the voltage detection in the module is disabled when it's not driven. Might have to gather data from a live car.

[retepsnikrep]

I captured some more data from another IPU on the bench but the data is still eratic with no obvious corelation between IGBT input voltage and a byte in the data stream it outputs, looks like I will have to treble check it with a live car.

[samwichse]

I'm still seeing that behavior in byte 1 (again ID = byte 0, checksum = 5)... I dropped all but the 0-200 data and massaged it a bit to show what I was talking about.

Data is based on the second run in the 0-200v data2... check the Analysis sheet.

https://docs.google.com/spreadsheet/...nJWenV1end6R2c (can't upload any more files, I've reached my ridiculously low quota for the site)

Sam

[retepsnikrep]

I had assumed my logic analyser had worked out the correct format for the serial data before I imported it into excel. Duh !!! I was a bit surprised it had no parity as most of the other Honda stuff i had studied does, so when I changed the analyser settings and forced it to have even parity the data changed significantly and there is now a clear corelation between igbt input voltage and the first data byte in each packet. Oh well at least I have found the issue. See attached.

The MPI Voltage is the first byte in each packet x 2, that makes sense and coreleates with the fact the mpi voltage jumps by two volts at a time when being monitored by the honda scan tool.

Now I can work on the interceptor.

I shall delete my prev posted spreadsheets!

http://www.insightcentral.net/forums...0v-data-ep.zip