EU Duty Cycle to Duration conversion issue...
#1
EU Duty Cycle to Duration conversion issue...
Matty was having an issue when the EU converts his Duty Cycle values in his fuel map to Duration, so I looked into why.
From here: http://www.stealth316.com/2-calc-idc.htm
Basically, IDC(%) = RPMxIPW/1200 or conversely IPW(ms) = IDCx1200/RPM.
Using Stealth 316s example, if IDC=75% and RPM=6000, IPW=15ms, but the EU says 7.5ms.
Greddy incorrectly used the time for one revolution instead of two revolutions.
6000rev/min x 1min/60sec = 100rev/sec
1/100rev/sec = 0.01sec/rev = 10ms/rev, so two revolutions takes 20ms.
This is where Greddy went wrong.
7.5ms/10ms = 75% duty cycle
Correct result is
15ms/20ms = 75% duty cycle
Dandy,
Can you check your BETA version to see if this is still an issue? If it is, pass it on to Greddy.
From here: http://www.stealth316.com/2-calc-idc.htm
Basically, IDC(%) = RPMxIPW/1200 or conversely IPW(ms) = IDCx1200/RPM.
Using Stealth 316s example, if IDC=75% and RPM=6000, IPW=15ms, but the EU says 7.5ms.
Greddy incorrectly used the time for one revolution instead of two revolutions.
6000rev/min x 1min/60sec = 100rev/sec
1/100rev/sec = 0.01sec/rev = 10ms/rev, so two revolutions takes 20ms.
This is where Greddy went wrong.
7.5ms/10ms = 75% duty cycle
Correct result is
15ms/20ms = 75% duty cycle
Dandy,
Can you check your BETA version to see if this is still an issue? If it is, pass it on to Greddy.
#2
Also another point, the I/J Add map is limited to +/-20ms.
So, if you use a Duty Cycle in a low RPM cell and convert, the EU support tool limits the Duration values to 20ms. Then if you convert back to Duty Cycle, the limited value is used, so you end up with the equivalent Duty Cycle instead of the original value.
Pretty cool 'feature'...haha.
So, if you use a Duty Cycle in a low RPM cell and convert, the EU support tool limits the Duration values to 20ms. Then if you convert back to Duty Cycle, the limited value is used, so you end up with the equivalent Duty Cycle instead of the original value.
Pretty cool 'feature'...haha.
#6
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Posts: 1,204
Originally Posted by IceY2K1
Greddy incorrectly used the time for one revolution instead of two revolutions
#9
Originally Posted by eng92
Although it does not apply in our case, Greddy's conversion would be accurate for engines that use simultaneous multi-port fuel injection (injectors are all fired simultaneously once every crankshaft revolution)
That could be why it's set up that way. I'll see what they say, but I have been aware of this for a while too. Will check my latest version. BTW, they are saying end of the month for the update now. I guess they keep adding things into the update. For the VQ30 it's ready but it sounds like they're doing other things for other engines also and rolling them out together.
#10
Hmmmm...found something else interesting.
Back when I was having issues with my injectors going static, logs showed IPW=11.2-11.5ms while DC=100% from 5323rpm-6400rpm, which isn't correct.
Later, whatever I did by accident fix it and the logging is correct.
Back when I was having issues with my injectors going static, logs showed IPW=11.2-11.5ms while DC=100% from 5323rpm-6400rpm, which isn't correct.
Later, whatever I did by accident fix it and the logging is correct.
#11
Sorry to bump this, I dunno if this was discussed earlier but in Dandy's EU file he said he didn't know if the DC to Duration conversion was fixed.
In version 2.20 it is fixed. I am going to use AutoTune to help me start my tune today and wanted to check if the conversion was fixed and it is
In version 2.20 it is fixed. I am going to use AutoTune to help me start my tune today and wanted to check if the conversion was fixed and it is
#12
Yes it was fixed. Also, when I was running the EU I went into the menu section where you input before/after injector sizes and my car ran great after that. I didn't even make many adjustments to the maps.
#14
Sorry for this bump in, I'm about to buy a PC laptop for the tuning with EU and was wondering what OS are you guy using ? Most new laptop come with W7 but I have an extra licence of WXP32 if require.
Thanks
AA
Thanks
AA
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