Interesting info on B3702 Injection timing

[joecar]

Links:
http://www.hptuners.com/forum/showth...ereencing-what
http://www.hptuners.com/forum/showth...ight=injection
http://www.hptuners.com/forum/showth...njector-Timing

Ok, thanks.

[Gelf VXR]

Looking at the calibrations in the HPT software, I see where the boundary angle of 520 degrees came from (not shown in EfiLive), and in the other forums its said that the boundary 520 - (Normal ECT + Normal RPM) = EOI. For example 520 - (110 + 4.56) = 405.44 BTDC Ignition EOI or 45.44 BTDC for EVC/IVO events, which is where we think it should just be before IVO.

But what happens when the engine is cold, for example 520 - (245 + 4.56) = 270.44 BTDC Ignition EOI or 89.56 ATDC with the inlet valve wide open, which cannot be correct for vaporisation??

If the boundary is 520 degrees BTDC, advancing the SOI and consequentially the EOI, surely the calculation should be 520 + (245 + 4.56) = 769.56 BTDC or 49.56 BTDC of the previous cycle ignition, and so for a hot engine, 520 + (110 + 4.56) = 634.56 BTDC or 85.44 ATDC of the previous cycle ignition, but 270 degrees before TDC EVO/IVO events?


Also, in the HP software the values for Normal ECT and Normal RPM are 50% less than EFI live calibration??

EfiLive show 220 degrees advance at +68 C, HPT shows 110

EfiLive shows 9.13degrees advance at 1150RPM and 185.8 at 4090RPM, HPT shows 4.56 and 92.9

Its not just a case for doubling the boundary value to arrive at EfiLive value (its not visible to check) as the end calculation is not the same?

Why would EfiLive show different values for the same calibration in HPT? All the other calibration data I've compared is the same?


Ive added a diagram I found to more easily identify with SOI EOI events

[Gelf VXR]

Cracked it, well almost, the injector cycle starts 200° BTDC Ignition stroke of the previous cycle, the earliest SOI for the next cycle and finishes 160° ATDC induction stroke of the current cycle, the latest EOI for the current cycle, just before IVC.

But there is still the discrepancy in the calibrations between HPT and EfiLive

Using HPT calibration data at 1150RPM

Calculating advance from 520° ATDC, engine COLD, 520 - (245 + 4.56) = 270.44 ATDC or 89.66 BTDC before EVC/IVO events

Calculating advance from 520° ATDC, engine HOT, 520 - (110 + 4.56) = 405.44 ATDC or 45.66 ATDC after EVC/IVO events ?? Injecting IVO explains the fuel smell for positive overlap cams and the success advancing EOI for the EVC?.

Using EfiLive calibration data at 1150RPM

Calculating advance from 520° ATDC, engine COLD, 520 - (490 + 9.13) = 20.87 ATDC Ignition stroke or 339.13 BTDC well before EVC/IVO events ??

Calculating advance from 520° ATDC, engine HOT, 520 - (220 + 9.13) = 290.87 ATDC Ignition stroke or 69.13 BTDC just before EVC/IVO events ?



More on the boundary angle of 520 degrees, courtesy of Chris HPT.

Boundary is the latest point in time that fuel can make it into the cylinder for the current injection period. It is measured in degrees AFTER TDC compression. It is also the earliest the injector can fire again after the completion of the last injection event. ie. the boundary defines the start/end of a complete injection cycle.

Normal End of Injection Target (EOIT) is the angle before the boundary (in degrees) that the normal pulse (the main pulse) should finish. The hardware calculates the start of injection time from the EOIT and the desired PW.

Makeup End of Injection Target (EOIT) is the angle before the boundary (in degrees) that the first makeup pulse should finish. Makeup pulses are extra pulses that can be injected to inject more fuel during an injection cycle rather than having to wait for the next cycle. There can be more than one makeup pulse but the makeup EOIT specifies the EOIT of the first makeup pulse.

The makeup PW minimum is a minimum PW for the makeup pulses, they cannot be shorter than this (if they are they don't happen).

So you have the boundary that defines the injection cycle, a normal EOIT that specifies the EOIT for the main pulse, and finally a makeup EOIT that specifies the EIOT for any makeup pulses that might be needed if a fuel increase is commanded during an injection cycle but after the main pulse has occurred.

Hope that helps.

Chris...


What is the boundary value for EfiLive and its calculation if it is handled differently HPT?

[Highlander]

Cracked it, well almost, the injector cycle starts 200° BTDC Ignition stroke of the previous cycle, the earliest SOI for the next cycle and finishes 160° ATDC induction stroke of the current cycle, the latest EOI for the current cycle, just before IVC.

But there is still the discrepancy in the calibrations between HPT and EfiLive

Using HPT calibration data at 1150RPM

Calculating advance from 520° ATDC, engine COLD, 520 - (245 + 4.56) = 270.44 ATDC or 89.66 BTDC before EVC/IVO events

Calculating advance from 520° ATDC, engine HOT, 520 - (110 + 4.56) = 405.44 ATDC or 45.66 ATDC after EVC/IVO events ?? Injecting IVO explains the fuel smell for positive overlap cams and the success advancing EOI for the EVC?.

Using EfiLive calibration data at 1150RPM

Calculating advance from 520° ATDC, engine COLD, 520 - (490 + 9.13) = 20.87 ATDC Ignition stroke or 339.13 BTDC well before EVC/IVO events ??

Calculating advance from 520° ATDC, engine HOT, 520 - (220 + 9.13) = 290.87 ATDC Ignition stroke or 69.13 BTDC just before EVC/IVO events ?



More on the boundary angle of 520 degrees, courtesy of Chris HPT.

Boundary is the latest point in time that fuel can make it into the cylinder for the current injection period. It is measured in degrees AFTER TDC compression. It is also the earliest the injector can fire again after the completion of the last injection event. ie. the boundary defines the start/end of a complete injection cycle.

Normal End of Injection Target (EOIT) is the angle before the boundary (in degrees) that the normal pulse (the main pulse) should finish. The hardware calculates the start of injection time from the EOIT and the desired PW.

Makeup End of Injection Target (EOIT) is the angle before the boundary (in degrees) that the first makeup pulse should finish. Makeup pulses are extra pulses that can be injected to inject more fuel during an injection cycle rather than having to wait for the next cycle. There can be more than one makeup pulse but the makeup EOIT specifies the EOIT of the first makeup pulse.

The makeup PW minimum is a minimum PW for the makeup pulses, they cannot be shorter than this (if they are they don't happen).

So you have the boundary that defines the injection cycle, a normal EOIT that specifies the EOIT for the main pulse, and finally a makeup EOIT that specifies the EIOT for any makeup pulses that might be needed if a fuel increase is commanded during an injection cycle but after the main pulse has occurred.

Hope that helps.

Chris...


What is the boundary value for EfiLive and its calculation if it is handled differently HPT?

You are basing your calculations on the e38s?

where does the angle come from? The 0411 ecu uses a reference of time!

[joecar]

He using an LS1B/0411...

[joecar]

Gelf, draw some pictures.

[Gelf VXR]

You are basing your calculations on the e38s?

where does the angle come from? The 0411 ecu uses a reference of time!

In my last post I am referring to Gen 4, all the injector timing data is the same for LS2, LS3 and LS7.

The boundary angle is shown in HPT as 520° (its not shown in EfiLive)

HPT description "Injection Boundary: The latest possible crank angle that the injection pulse can finish for fuel to be delivered to the cylinder"

It does not state TDC, however Chris from HPT noted that "Boundary is the latest point in time that fuel can make it into the cylinder for the current injection period. It is measured in degrees AFTER TDC compression. It is also the earliest the injector can fire again after the completion of the last injection event. ie. the boundary defines the start/end of a complete injection cycle."

Then we have,

{B1205} Injector timing ECT

EfiLive description "This table will offset the actual opening of the injector referenced to engine coolant temperature."

HPT description "Normal EOI target adder vs. ECT: Adds to the normal end of injection target

Advances EOI earlier when cold to allow more time for vaporisation

{B1206} Injector timing RPM

EfiLive description "This table will offset the actual opening of the injector referenced to RPM."

HPT description "Normal EOI target adder vs. RPM: The target angle before the boundary that the normal injection pulse should finish"

Advances EOI earlier to compensate for less time per crank angel degree rotation to allow more time for vaporisation



For Gen 3, the LS1

The boundary angle is shown in HPT as 6.5 ATDC (its not shown in EfiLive)

HPT description "Injection Boundary: Fuel injection delivery boundary as a number of reference periods after TDC"

From Bluecat's post http://www.hptuners.com/forum/showth...iming&p=238797, he confirmed reference period or reference pulse as 90° crank angle

6.5 * 90° = 585° ATDC (65° later than gen 4, very close to IVC)

Then we have

{B3702} Injector Timing There is no RPM adjustment for the gen 3.

EfiLive description "This table will offset the actual opening of the injector referenced to the reference pulses and engine coolant temperature."

And here's one confusion I think, the table axis in EfiLive shows mS, does this mean Milliseconds?, its reference pulses as per the description. (If you check {B4003} or {B4004} the IPW table axis its shows Milliseconds not mS)

HPT description "Normal injection target vs. ECT. The end of injection target measured in reference periods after the injection boundary that the normal injection should finish"

And here's another confusion, for the gen 4, the target angle is before the boundary, advancing EOI. For gen 3 it states measured in reference periods after the injection boundary that the normal injection should finish. The target angle is after the boundary.

From Bluecat's post I've seen -784 + ((Boundary + Normal) * 90) = -784 + ((6.5 + 5.55) * 90) = 300.5 ATDC EOI, as it fits best with the simulated results.

I think if EOI is to be calculated from the calibration data it should be as follows, the boundary is defined 6.5 * 90 = 585 ATDC or 135 BTDC compression/ignition, the start and end of the injection cycle. Then as per the description "The end of injection target measured in reference periods after the injection boundary that the normal injection should finish"

So EOI is 5.55 * 90 = 499.5° after the boundary ST/END which is 135° BTDC. 499.5 - 135 = 364.5 ATDC or 4.5° ATDC as EVC & IVO, but is 64° later than Bluecat's findings?

What really interesting thou is if you substitute gen 3 start/end of injection cycle with gen 4 start/end of injection cycle value, 135 to 200

499.5 - 200 = 299.5

Its 1° difference

[Gelf VXR]

Gelf, draw some pictures.

Some excel sheet screen shots for SOI and EOI for 2ms, 5ms, 10ms and 15ms IPW. High light green the inlet is open, high light red the exhaust valve is open, its stock LS2 cam events so there is no overlap.

What you can observe is that on a hot engine at low rpm, and low IPW, the injectors are opening and closing on an open inlet valve. In cold conditions and/or higher rpm, SOI and EOI happens while EVO, at very high RPM SOI is before EVO, EOI is while EVO

[Gelf VXR]

I've made a spread sheet for both gen 3 & 4 to show SOI and EOI vs RPM, ECT and IPW. It doesn't seem to want to upload, a couple of screen shots attached

edit, added gen 4 with efilive ECT and RPM data, now looks similar to gen 3

[Gelf VXR]

Because of the differences between the gen 4 calibrations between EfiLive and HPT, I'm going to jump to some conclusions.

I think HPT gen 4 calibration data for injector timing is suspect, here's why

The gen 3 calibrations are the same in both EfiLive and HPT, however the boundary isn't shown in efilive, but it seems logical that 585ATDC would be acceptable as per the description "Boundary is the latest point in time that fuel can make it into the cylinder for the current injection period. It is measured in degrees AFTER TDC compression. Which would be as the inlet valve closes.

Stock IVC ATDC compression for

LS1 = 581.5, later 580.5
LS2 = 582
LS3 = 583
LS6 = 582, later 583
LS7 = 588

All around 585° (the boundary could be modified to cams exact IVC, at 0.05")

If I ignore the 520° boundary in HPT gen 4 and use 585° as the boundary and use EfiLive gen 4 calibration data, the results are practically the same SOI and EOI as the gen 3, apart from EOI advances with RPM in the gen 4 as expected because gen 3 does not have provision for RPM advance.

When the engine is up to temperature, both tables show EOI 365° ATDC compression

Stock IV0 ATDC compression for

LS1 = 375, later 373.5
LS2 = 378
LS3 = 379
LS6 = 378, later 379
LS7 = 378

EOI is just before the IVO (the Normal advance vs ECT could be modified for new cams earlier IVO, EVC is irrelevant if EOI is before IVO with regard to overlap and fuel out the exhaust valve)

It reasonable to assume that GM would stick to similar values across all the platforms? Correction, although the LS1 boundary is 585°, it has been shown to start from 65BTDC which means the boundary is the same gen 4 at 520° ATDC
Tables attached for comparison