I have a 1986 Skoda Rapid that will get the new engine from Skoda Fabia and the GenBoard. I purchased this engine with whole accessories like injectors, electric throttle body, ignition module mounted over plugs, MAP and IAT, but without ECU. I'm interested in electronics and engine management..
My setup:
Genboard version 3.3, s.n. 301
Engine:
It is 4 cylinder 1397 ccm OHV, distributerless wastedspark ignition.
Ignition out
Original VW module. It have two logic level inputs for 1-4 and 2-3 cylinder, without dwell control. It takes spark at falling edge. It need less than 10 mA input current, so I dont need ignition IGBTs.
The common solution is to use 74HC259 output, with 510 Ohm (270 Ohm..1kOhm). See assembled controller specs in WebShop for which channels are traditionally used: check the 6+2 configuration: (namely channel3=EC36pin36 and channel5=EC36pin12 are logic-level) but you can use any, of course.
Thanks for info!
Trigger
Primary: VR, I connected JP2 with JP7 and shorted SJ6
I tried to connect square signal to primary triger input via cap and it seems to be working..
Secondary: Hall on cam.
I found this Abaut config for v3.3: "v3.3 Secondary trigger (Trigg2) Hall setup: nothing to do"
There are several pages abaut Secondary trigger (Trigg2) Hall setup, but only one with info abaut v3.3
See
- GenBoard/Manual/InputTrigger
- GenBoard/Manual/InputTriggerHardWare
- InputTrigger
- http://vems.hu/www.vems.co.uk/VEMS/InputTrigger.html
Throttle
Electronically controlled with DC motor. I want use it only because I purchased it with engine. If someone want, I can exchange it for standard throttle. I'm mot fully decided for use it or exchange.
This throttle body is originally mounted on this engine. It have TPS sensor. My configuration is like on this page
http://www.egr.msu.edu/autoweb/Class/Proj_2001/throttle/project.htm.
Nice ! What is the throttle type exactly ? Maybe photo ?
I'll put some photos and info later. It looks nearly same as one at link above, but only 45 mm diameter.
- file upload is on bottom of DocsPage
So my plans are to make separate unit that will read TPS and Pedal Position then compare values, make some adjustment and calculate PWM for H-bridge. Initial position of throttle is little open so I think that for normal iddle it need little closing.
It is very reasonable to put
- RPM into the equation: at low RPM, apply nonlinear pedal position=>throttle angle. This enhances drivability (the only reason for electronic throttle, right?)
- and possibly MAP feedback would be nice too. This means closed loop: the direct PWM(TPS, RPM) function is only a reference PWM value, and MAP(TPS, RPM) is the target value that is maintained with a (eg. PID) controller algorithm. This means that actual PWM can diverge somewhat (eg. +-10%) from the reference PWM(TPS, RPM). Open-loop PWM(TPS, RPM) is OK to try first, might give perfect results without added complexity.
I understand that you need a several-ampere H-bridge driver (as an addon hardware, since the stepper output can only drive 1A, or max 2A if 2 channels are connected parallel on both input and output), but what else would be needed on that device? It's better to put anything else into genboard firmware.
Here is some info about DC motor in throttle:
- lockup current (typical) 9.5 A
- maximum constant current at 212°F 2.5 A (effective value)
- nominal current (no-load) < 1.5 A (average value)
- maximum allowed generator current < 10.0 A
Yes it could be nice to have implemented this in genboard firmware. But I haven't many experiences with programing. I didn't study genboard sources in detail. Can someone help "howto implement Electronically controlled throttle to Genboard code"? :-) Any template.. :-)
It's easier to put the code in the firmware than into an external board. If the solenoid wants a fixed frequency signal, the same approach can be used as in boostcontrol.c. Otherwise it's even easier: softpwm.c.
Just be sure to configure overrun fuelcut to prevent engine from overrevving when TPS is near 0% (<iac_tps_thres) and the electronic throttle is opened more than it should (for some reason, eg. during development, or broken wires).