Homemade Boost Controller With Diagrams - Is this possible?
03-14-2006, 01:17 PM
#12
0.0 BAR
Join Date: May 2005
Posts: 0
Re: Homemade Boost Controller With Diagrams - Is this possible?
That system would never be stable. It is undamped, even with the feedback. What would happen is that the boost would oscillate with the normal just around your "set" boost pressure. The damping ratio in this system is in fact zero, since the system is an on/off type and could never produce a steady-state value (+/- 2% of target value). With a damping ratio of zero, you would get at least 100% overshoot of your target boost pressure, ie a huge boost spike.
The good boost controllers use PWM because you can control the opening of the solenoid and produce a steady-state system. They also use a microcontroller to monitor the ramp up rate of the boost and adjust the damping ratio according, so they get pretty close to a critically damped system.
The good boost controllers use PWM because you can control the opening of the solenoid and produce a steady-state system. They also use a microcontroller to monitor the ramp up rate of the boost and adjust the damping ratio according, so they get pretty close to a critically damped system.
03-14-2006, 03:20 PM
#13
0.5 BAR
Thread Starter
Join Date: Mar 2006
Posts: 57
Re: Homemade Boost Controller With Diagrams - Is this possible?
Originally Posted by CSaddict
Acclude are you Midnightmechanix on ebay? I noticed you sell chipping parts. It also seems that you use Xenocrons pictures to do your advertising?
Originally Posted by bumblezc
Hmm, I'm glad I bought my Beta TullosTech EBC that has datalogging/firmware loading/close/open loop operation for 100.00!!!!
Originally Posted by MADMAX
That system would never be stable. It is undamped, even with the feedback. What would happen is that the boost would oscillate with the normal just around your "set" boost pressure. The damping ratio in this system is in fact zero, since the system is an on/off type and could never produce a steady-state value (+/- 2% of target value). With a damping ratio of zero, you would get at least 100% overshoot of your target boost pressure, ie a huge boost spike.
The good boost controllers use PWM because you can control the opening of the solenoid and produce a steady-state system. They also use a microcontroller to monitor the ramp up rate of the boost and adjust the damping ratio according, so they get pretty close to a critically damped system.
The good boost controllers use PWM because you can control the opening of the solenoid and produce a steady-state system. They also use a microcontroller to monitor the ramp up rate of the boost and adjust the damping ratio according, so they get pretty close to a critically damped system.
It sounds like instead of either full open or full closed solenoid, I could add PWM modulation capabilites and then use the MAP signal compared to the RPM signal to adjust damping ratio based on the load.
What about using the Injector Pulse and MAP signal for PWM and then using the MAP, TPS and RPM signals for damping. That way high inj. freq. + higher MAP voltage = high freq. PWM. low inj. freq. + low MAP voltage = low freq. PWM and if the RPM's are high, MAP voltage is high, but TPS is closed, it will send the modulated signal to the solenoid. It still seems do-able to me.
03-14-2006, 04:22 PM
#14
0.5 BAR
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Join Date: Mar 2006
Posts: 57
Re: Homemade Boost Controller With Diagrams - Is this possible?
I did some more research....
What about using a PWM proprtional single coil driver and a PWM solenoid to control the boost.
It looks like it would still require the comparator chip getting V- from the MAP and V+ from the adjustable **** to use as a trigger for the PWM driver. That way it's still adjustable from the driver seat. I could use a potentiometer to adjust the driver signal sent to the solenoid.
It solenoid would be triggered anytime the Map voltage passes the **** setting voltage. The driver would pulse the signal going to the solenoid and it's adjustable from 100-2200 mhz frequency and accurate within less than 1% of the desired output.
It would not simply be full open or full closed anymore. It would vary the amount that it opens and closes.
The only thing this setup is not taking into consideration is engine load, or RPM's/Throttle position. Maybe it's not needed. Anyone got input on this setup?
What about using a PWM proprtional single coil driver and a PWM solenoid to control the boost.
It looks like it would still require the comparator chip getting V- from the MAP and V+ from the adjustable **** to use as a trigger for the PWM driver. That way it's still adjustable from the driver seat. I could use a potentiometer to adjust the driver signal sent to the solenoid.
It solenoid would be triggered anytime the Map voltage passes the **** setting voltage. The driver would pulse the signal going to the solenoid and it's adjustable from 100-2200 mhz frequency and accurate within less than 1% of the desired output.
It would not simply be full open or full closed anymore. It would vary the amount that it opens and closes.
The only thing this setup is not taking into consideration is engine load, or RPM's/Throttle position. Maybe it's not needed. Anyone got input on this setup?
03-14-2006, 06:57 PM
#17
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Join Date: May 2005
Posts: 0
Re: Homemade Boost Controller With Diagrams - Is this possible?
Actually it is easy, it just takes some processing to do it. A microcontroller could handle the job easily. The only time consuming part is the coding and proper hardware design.
03-14-2006, 09:13 PM
#18
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Join Date: Mar 2006
Posts: 57
Re: Homemade Boost Controller With Diagrams - Is this possible?
Only issue with that is $$$ I'm a cheap bastard as stated at least 5 times in this thread already.
Unless a cheap kit like this will work it's out of my price range.
http://cgi.ebay.com/8052-Microcontro...QQcmdZViewItem
I have some very rusty programming skills and used to mess with Basic a lot in my younger days. It's a standard serial interface with the PC so I don't think it would be too much of a hassle to get up and going. I'd just need a big book of codes and their meanings and I'd be straight. I also don't know if a kit like this would for this particular application. Anyone insight Swap_File?
A step up from this with RAM for memory to datalog the all of the boost input would be nice
Unless a cheap kit like this will work it's out of my price range.
http://cgi.ebay.com/8052-Microcontro...QQcmdZViewItem
I have some very rusty programming skills and used to mess with Basic a lot in my younger days. It's a standard serial interface with the PC so I don't think it would be too much of a hassle to get up and going. I'd just need a big book of codes and their meanings and I'd be straight. I also don't know if a kit like this would for this particular application. Anyone insight Swap_File?
A step up from this with RAM for memory to datalog the all of the boost input would be nice
03-14-2006, 10:14 PM
#19
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Join Date: Oct 2005
Posts: 29
Re: Homemade Boost Controller With Diagrams - Is this possible?
I have never worked with Basic stamps, only PICs and the Motorola HC12. The PIC/EPROM programmer I use now is the Willem PCB4.5C from http://www.sivava.com/ . It can do EPROMs for ECUs, and PIC chips, and all kinds of other stuff. It has been very handy. While there are cheaper programmers, none I have found can do as large of variety of chips as this one can, at this price.
PIC chips can be sampled for free from http://sample.microchip.com/ .
The rest of the software for programming PICs can be found for free online.
I am trying to think of an easier way to do this, but until I get my car boosted, I have nothing to experiment on.
PIC chips can be sampled for free from http://sample.microchip.com/ .
The rest of the software for programming PICs can be found for free online.
I am trying to think of an easier way to do this, but until I get my car boosted, I have nothing to experiment on.
03-15-2006, 09:25 AM
#20
1.5 BAR
Join Date: Aug 2003
Posts: 1,194
Re: Homemade Boost Controller With Diagrams - Is this possible?
Originally Posted by MADMAX
Actually it is easy, it just takes some processing to do it. A microcontroller could handle the job easily. The only time consuming part is the coding and proper hardware design.
