COP Ignition Development
Here is some information, on how to make RPM and timing advance measurements based on signals captured with a logic analyzer. The development board has connection to the logic analyzer for 6 of the 8 ignition drivers, tab wheel, and CID. The tab wheel is high for 50 crank degrees, and low for 40 degrees or one cylinder slot of 90 degrees. CID is goes high about 45 degrees into cylinder 1 slot, stays high for 4 cylinders, that is crank revolution. Then CID is low for 4 cylinders, sync is checked on each CID edge. Both the TAB and CID change with crankshaft angles, there is no mechanical advance, and unlike the MOPAR reluctor and pickup, there is no timing variation related to signal amplitude variation with engine speed. The picture below show a capture with RPM increasing from idle to 4000 RPM in a loop. A zoom feature is used to view and measure in detail.
The picture below shows how to measure the CID period and convert to RPM. At the bottom CID is high for 15.04 ms (time for one RPM). to convert to RPM, divide 60 by 0.01504 or 3,989 RPM. That RPM is used gather desired timing advance value from user specified advance table, it is 28 degrees. Now measurements are used to calculate timing advance. Below click on picture to expand. Cursor line A2 is at base timing set at distributor. A1 is at ignition point of cyl1 when signal drops. Before that signal is high for the dwell period of about 1.6 ms. Measuring the difference of A2 to A1 is 1.164 ms. That will be used later to convert to degrees of timing advance from base timing.
The picture below shows the measurement in time, of the 40 degree period of the tab wheel. The 1.164 ms measured above is divided by 1.663 ms and multiplied by 40. This gives a calculated advance of 40 x 1.164/1.663 of 28 degrees and is correct based on timing table.
The COP ECU adjusts timing for each cylinder event. As RPM and engine vacuum varies, the timing advance is calculated by interpolating tables. The actual engine timing is available on user real time display, including RPM, the advance that is RPM and vacuum derived.
The COP system is easily static timed by setting crank to desired base timing, then setting distributor so that the trailing edge of #1 tab window aligns with optical sensor slot. That timing is then verified and set as base timing.
Here is some information, on how to make RPM and timing advance measurements based on signals captured with a logic analyzer. The development board has connection to the logic analyzer for 6 of the 8 ignition drivers, tab wheel, and CID. The tab wheel is high for 50 crank degrees, and low for 40 degrees or one cylinder slot of 90 degrees. CID is goes high about 45 degrees into cylinder 1 slot, stays high for 4 cylinders, that is crank revolution. Then CID is low for 4 cylinders, sync is checked on each CID edge. Both the TAB and CID change with crankshaft angles, there is no mechanical advance, and unlike the MOPAR reluctor and pickup, there is no timing variation related to signal amplitude variation with engine speed. The picture below show a capture with RPM increasing from idle to 4000 RPM in a loop. A zoom feature is used to view and measure in detail.
The picture below shows how to measure the CID period and convert to RPM. At the bottom CID is high for 15.04 ms (time for one RPM). to convert to RPM, divide 60 by 0.01504 or 3,989 RPM. That RPM is used gather desired timing advance value from user specified advance table, it is 28 degrees. Now measurements are used to calculate timing advance. Below click on picture to expand. Cursor line A2 is at base timing set at distributor. A1 is at ignition point of cyl1 when signal drops. Before that signal is high for the dwell period of about 1.6 ms. Measuring the difference of A2 to A1 is 1.164 ms. That will be used later to convert to degrees of timing advance from base timing.
The picture below shows the measurement in time, of the 40 degree period of the tab wheel. The 1.164 ms measured above is divided by 1.663 ms and multiplied by 40. This gives a calculated advance of 40 x 1.164/1.663 of 28 degrees and is correct based on timing table.
The COP ECU adjusts timing for each cylinder event. As RPM and engine vacuum varies, the timing advance is calculated by interpolating tables. The actual engine timing is available on user real time display, including RPM, the advance that is RPM and vacuum derived.
The COP system is easily static timed by setting crank to desired base timing, then setting distributor so that the trailing edge of #1 tab window aligns with optical sensor slot. That timing is then verified and set as base timing.
