Date: Sat, 16 Feb 2002 20:42:22 -0000 From: "John Banks" <jcsbanksnopsamali.co.uk> Subject: [LONG] Open source electronic boost controller circuit and code
Long, but hopefully interesting thread... I have a Subaru Impreza Turbo and have been working on an electronic boost controller. It could be used on just about any turbocharged car with appropriate modification. It uses Atmel AVR microcontroller AT90S4433 RISC at 8MHz and is programmed in BASIC (!) using BASCOM-AVR free demo compiler. see www.dontronics.com - I started with a DT006 development board which I programmed from the parallel port. There is onboard RS232. It currently takes inputs from the manifold pressure sensor, throttle position sensor, and four potentiometers which set base duty cycle, proportional gain, integral gain, differential gain. The boost target is static across the RPM range and is set in software at 18 PSI. I am using the factory duty solenoid and manifold pressure sensor. I have tested it on the car and it works very well. It spools up as quickly as a ball-spring manual boost controller or a disconnected wastegate, and achieves the same boost in every gear and different conditions (subject to the flow limits of the TD04L turbo) without spiking. Present plans for me to add are a map of duty cycles and boost targets based on RPM. I need to also work on the serial interface to allow programming via the serial port of a laptop. I need to write code to read/write EEPROM for storage of these parameters. The circuit and code are very simple. It is open source, but I retain copyright and I do not give you permission to market it commercially. If you use it, have any comments or improve it in any way, or have any ideas I would be delighted to hear from you! If anyone knows any other circuits on the web for EBCs I would like to know. I have not found any that show their circuit or code. Thanks for reading this long post. See below for links to code and circuit. CIRCUIT http://www.i-club.com/forums/attachment.php?s=&postid=1454322 Note typo - transistor is TIP 122 not 127. http://www.i-club.com/forums/attachment.php?s=&postid=1454274 Thread discussing it on I-club http://www.i-club.com/forums/showthread.php?s=&threadid=137309&perpage=25&pa genumber=1 I also posted it on http://bbs.22b.com and http://www.scoobynet.co.uk/bbs Drivetrain forum.
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