john banks
16-02-2002, 21:12
I hope you don't mind a Subaru nut that loves all things turbocharged coming onto your board.
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.
CODE
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.
Please note that raising the boost on any turbocharged vehicle needs careful thought. I am unknowledgable on VAG 1.8T engines.
On a Subaru the fuelling is sensible even raising boost by 5 PSI across the range as it is MAF based. The injectors are nowhere near maximum duty cycle. The intake and exhaust gas temperatures are sensible as is the ignition timing and there is no knock. You may also be limited by an overboost fuel cut.
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.
CODE
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.
Please note that raising the boost on any turbocharged vehicle needs careful thought. I am unknowledgable on VAG 1.8T engines.
On a Subaru the fuelling is sensible even raising boost by 5 PSI across the range as it is MAF based. The injectors are nowhere near maximum duty cycle. The intake and exhaust gas temperatures are sensible as is the ignition timing and there is no knock. You may also be limited by an overboost fuel cut.