New Autronic pages
Autronic trigger and Ignition Setup
Autronic Ignition Setup
One of the most important things in ECU setups is the crankshaft and camshaft trigger setup. If setup is not correct, ECU’s ignition and injection times might not be accurate.
For 4-cyl engine Autronic recommends 4 trigger events / 720 degrees, about 60 degrees before TDC.
How to setup the triggers:
- Turn the engine so that Cyl1 is 60 degrees before TDC (BTDC)
- Position the trigger disc so that the tooth is in the center of the crank sensor
- Now turn the engine so that the crank sensor is between the tooth and the next tooth. 10 degrees after the previous one and more than 10 degrees before the next one.
- Now adjust the cam sensor so that the camshaft tooth is in the center of the sensor.
HINT: SM4 firmware 1.09 and later supports a Cyl/Sync/HIS scope feature which makes trigger troubleshooting very easy.
Next is the Ignition Setup parameter setup in ECUCAL M-1, Ignition Setup screen:
 |
1. Ignition O/P’s: Since my car is equipped with individual coil packs, I need to select 4 O/P 4Cyl MC, 4 Cylinders, MultiCoil. If you press Enter at Parameter 1, Ignition O/P and select Advanced you can see the ignition timing events. 2. Ign trigger edge: This is set to –ve edge (DWELL) and this varies depending what coils you have. This is what I use with Honda S2000 coils 3. Dwell/pulse times: User defined, since I’m using my own Dwell table 4. Ign delay time: This is how long it takes for the coil to produce the spark. I measured this using an oscilloscope and is the time from the trigger event till the spark was given. 5. Ign retard clamp: Max amount of advance allowed 6. Gin advance clamp: Max amount of retard allowed |
Next select M-1, I/P Cylinder & sync:
 |
1. Trig decoder: Cylinder pulses 2. Trigger events/cycle: This is the amount of triggers / 720 engine degrees. 2 crank triggers = 4, 3 crank triggers = 6 etc… 3. Cylinder I/P lead: 69 degrees in my case. Very important setting and affects directly to ignition accuracy. See Tuning I/P Lead 4. Digital angle filter: The Digital Angle filter relates to the predictive ignition timing algorithm which is most noticable during engine acceleration and deceleration. When set to Fast it is necessary for the cylinder pulses to have highly accurate spacing otherwise any errors in the cylinder pulse spacing can be amplified. When set to Slow the algorothim determines the engine position over more cylinder pulses so any pulse spacing errors are filtered out. 5. Cylinder sensor: Choices are reluctor or Hall type. When using reluctor type, make sure wave rises and then falls when triggered. I’m using GT101 Hall sensor, so I must use Hall. 6. Cylinder trig edge: Rising in my case since signal rises when the trigger passes the sensor. NOTE: For reluctor type this has to be Falling 7. Cylinder I/P filter: Slow. If less than 10 crank pulses, use Slow. Otherwise Fast. 8. Sync Sensor: This refers to Cam sensor and same logic as with Cylinder sensor setting is used. I use GT101 as a Cam sensor as well. 9. Sync trigger edge: Same logic as Cylinder trigger edge 10. Sync I/P signal: Must be set to Yes if Knock detection is used and also should be set to Yes when used with Multi-coil systems like in my case. NOTE: Ignition is inhibited If set to Yes and Sync signal is not received. 11. Measure freg: Disabled 12. Alternate cam2 input: Disabled since I’m using one Sync trigger 13. RPM>Sync Err Detect: 50rpm. Sync error detection is active after this RPM 14. RPM>CamPosErr detect: 500rpm. Camshaft position error detect RPM |
Engine should start after all these parameters are set correctly. Before we can call ignition setup complete, Cylinder I/P lead has to be tuned. Otherwise ignition event might not happen at the right time.
Tuning Cylinder I/P Lead:
For this you need to know when cyl 1 is at TDC. If you don’t have the timing marks, you need to create the marks. Just rotate the cylinder 1 to TDC and make sure cyl1 valves are closed and engine is at power stroke.
Next you need to modify your map so that timing table has flat 0 degree ignition advance at low and idle loads. All ignition trims must be disabled.
Connect your timing light to Cyl1 coil.
Start the engine and adjust the Cylinder I/P lead value until timing marks are aligned. Now the timing is accurate since ignition event happens at TDC, when 0 degree ignition advance is used.
Resources:
Autronic SM4: Launch control
Autronic SM4: Launch Control
First, what is Launch Control? Launch control is basically a lower RPM rev limiter allowing driver to hold the engine at full throttle and maintain RPM’s at Launch RPM. This is done by retarding the ignition or/and cutting the fuel. Turbocharged cars see an additional benefit in the ability to build boost. This gives you more consistent and reliable launches with maximum power. As an example...
CAUTION: Make sure your valve train in strong enough when using ignition retard. Valves might stay open in some cases so be careful. Also, take care if your car is equipped with catalytic converter.
Hardware installation: Installation is quite simple and can be done with one switch. In my case I have 2 switches connected to I/P SW1. One at clutch pedal and other in series used to deactivate the launch mode when needed. Same input is also used for WOT Shift.
Launch Parameters, programmed using Ecucal:
 |
1. Launch cut mode: In this case revs are limited by retarding ignition and cutting fuel. Other option is Fuel Cut. Ignition cut is more responsive but be careful as explained earlier… 2. Launch rpm trig: This parameter is used to activate the launch. In order for launch mode to activate, switch has to be on and RPM has to be less than this parameter, 3000rpm in my case. 3. Launch TPS: Switch has to be on and TPS below this limit to enter the Launch mode. 4. Launch KPH: Switch has to be on and the speed below this limit to enter the Launch mode. 5. Launch RPM Source: Can either be the single Launch RPM value in the line below or variable Launch RPM by using the GPC12 table. 6. Launch RPM: RPM used in launch mode. This is the lower RPM limiter and RPM is limited to this value when in Launch mode. 7. Launch RPM Offset: The Launch RPM Offset value is more for turbo engines to build boost but is the amount of RPM below the Launch limit that the ignition retard is fully applied. 8. Launch Rate: Rate the RPM limit increases once launch is cancelled either by the switch being released or the Launch ends speed being reached. 9. Launch ends: Speed at which launch is terminated. The Launch ends speed is Vehicle speed, not Driven wheel speed. 10. Ign retard source: Can either be from GPC 13 table or the single value in the Launch retard line. 11. Launch retard: Amount how much the ignition is retarded during launch mode. This parameter is not available if GPC13 is selected as the Launch retard source. In my case, ignition is retarded by 10 degrees. So, if advance in Main ignition table is 24 degrees, ignition is retarded by 10 degrees to 14 degrees. |
Launch activation and lower RPM limiter:
As described earlier, launch control system is basically a lower RPM limiter. Following picture shows a graph from the activation phase, parameters shown in this log:
|
(Double-click the picture to open the complete log, new tab is opened)
|
|
Engine is idling at 478.268 sec and clutch is pressed in as seen from the I/P SW1. In order to activate the launch mode, following must be true:
- RPM has to be below 3000rpm
- Throttle must be below 101%
- Speed has to be below 9kph
- I/P SW1 must be high
As seen from the log, all conditions are met. Launch mode is activated and Launch revlimit is set to 5000rpm as defined in the settings.
At 479 throttle is pressed in further and 5000rpm limit is reached. At this point, fuel injection is cut and no fuel is injected. Ignition is also retarded by 10 degrees as defined by the Launch retard parameter. See orange and brown traces.
No fuel = No combustion, air alone can’t explode as engine is just pumping air.
Note from Autronic, Ian Hamwood: Lean conditions can be caused on other cylinders with fuel cut because of reversion pulses. The cylinder that you fuel and spark cut may have been getting some fuel from another cylinder's reversion pulse so there is no problem there (wiil either be too lean to ignite or spark cut will inhibit combustion), but the cylinder being cut may be providing some fuel to another cylinder via reversion. That is what can cause the lean conditions on non-cut cylinders. In an engine with individual throttle bodies and no plenum you can get a slight lean out after a fuel cut if the runner was wet with fuel and the engine sucked the runner dry during the cut. With a v1.09 CPU if the transient fuel is enabled it can compensate for the runner drying effect after a fuel cut.
Roughly 250mS later fuel is injected again briefly to keep the engine running and then injection cut again.
At 479.376, clutch is released and car starts moving.
Below is a new graph, take a look at the Launch revlimit value. It is actually a revlimit calculated from Launch rate parameter and increases the Launch revlimit value until Launch ends value is reached or switch is released. If this “moving” revlimit is reached, power is reduced according to Launch Cut Mode parameter. An example of this can be seen at 480.125sec. This feature can be effectively used as a Traction control to limit the wheel spin. But, if you cut too much, your acceleration will be slower…
Launch continues and at 480.951 launch is terminated since Launch ends speed is reached. At the same time Launch revlimit value increases to 32767 and normal engine revlimit will be used from this point on. That’s pretty much all there is to it.
|
(Double-click the picture to open the complete log, new tab is opened)
|
|
How to find the optimum launch: Best parameter for this is the Vehicle speed (Non-Driven wheel speed) and how quickly the wheel speed increases. Take a log and select the point where the launch ends. Press T to enter the Tagged mode and select the time period you are interested in. Then press S to open the Statistics view. Note the Rate/Sec column and the value. Aim for the highest value here.
Here's the end result:
Next question is what is faster way to accelerate, keep wheels spinning or not? Read about it next week…
How Traction control works
It was raining here in northwest today, again...
Because it was wet, traction control activated few times and thought to show you how it can be seen from the logs.
Sensor Setup is as follows:
- Wheel speed is measured from existing ABS sensors using the VR amplifier I made. ABS is still functional.
- Driven wheel speed signal: HS1 Left rear, HSI2: Right left.
- Vehicles speed signal: HSI3
- TC switch in center console, modes, OFF, Dry and Wet. Used inputs I/P SW2 and I/P SW3.
Autronic ECUCAL setup:
TC Setup - General TC Settings. Notice that Fuel cut is used to limit power!
NOTE: Fuel Cut is used for demonstration purposes here. Actual setting and recommended by Autronic is Fuel & Ign Cut.
TC Ign Retard - These settings are not used since Fuel Cut is only used
Wet Setup - Settings used when switch is in Wet position
Dry Setup - Settings used when switch is in Dry position
Functionality can be seen from the trace below. Following traces are important:
Violet - Driven wheel sensor. Since BMW is rear wheel drive car, this trace is from rear wheels. Sensors are setup in Speed setup
Turgoise - Vehicle speed. Front wheel speed, non-driven wheel
Gold - Mean injection time
Trace: (Right click - View Image to see complete image)
Now, note where the cursor is: As you can see from the gold trace, fuel injection time is reduced when the speed difference between driven and vehicle speed signals is above the limits for specific gear defined in WET settings.
I have to say Autronic TC is very good and has saved me few times...