Worcester/Boston Social Thread
Feb 27, 2008, 11:00 AM
#8147
the easiest thing to do is using PWM to a FET of some sort switching the heater power directly, and then possibly Low Pass Filtered. The problem with this is that switching the FET induces alot of noise, in the mixed signal system.
PWC (Megasquirt) uses a regulated DC source controlled by precision DAC driven by the uC. I believe JAW also uses a regulated DC, controlled by the uC. I'm not entirely sure how JAW does it - but regulated DC is the best possible solution, because electrically its much quieter than driving a high power FET. I'm going to consult with my buddy Derek to see what he thinks. Hes picked up the torch as the electronics and microcontroller guru, where as i dropped the ball sometime ago in college.
Feb 27, 2008, 11:04 AM
#8148
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i never stopped working on the wb02 design. right now i'm trying to solve the issue of powering the heater.
the easiest thing to do is using PWM to a FET of some sort switching the heater power directly, and then possibly Low Pass Filtered. The problem with this is that switching the FET induces alot of noise, in the mixed signal system.
PWC (Megasquirt) uses a regulated DC source controlled by precision DAC driven by the uC. I believe JAW also uses a regulated DC, controlled by the uC. I'm not entirely sure how JAW does it - but regulated DC is the best possible solution, because electrically its much quieter than driving a high power FET. I'm going to consult with my buddy Derek to see what he thinks. Hes picked up the torch as the electronics and microcontroller guru, where as i dropped the ball sometime ago in college.
the easiest thing to do is using PWM to a FET of some sort switching the heater power directly, and then possibly Low Pass Filtered. The problem with this is that switching the FET induces alot of noise, in the mixed signal system.
PWC (Megasquirt) uses a regulated DC source controlled by precision DAC driven by the uC. I believe JAW also uses a regulated DC, controlled by the uC. I'm not entirely sure how JAW does it - but regulated DC is the best possible solution, because electrically its much quieter than driving a high power FET. I'm going to consult with my buddy Derek to see what he thinks. Hes picked up the torch as the electronics and microcontroller guru, where as i dropped the ball sometime ago in college.
Feb 27, 2008, 11:27 AM
#8150
seems like if the microcontroller has the ability to do it, then that would be the easiest thing to do. is there a specialized part that can do this? also, do you need feedback from the sensor to monitor temp or do you heat it and just keep it heated until you turn it off? it seems like once the exhaust is hot enough, heating the sensor isn't necessary, right?
sometimes people get away with powering the heater with a nominal 9VDC - only if they are not using a controller to read the A/F . This is enough voltage to heat the sensor enough so it does not clog the pump chamber, when still in the exhaust stream. You can't however just give it 9VDC on the H+/- and expect to get an accurate Lambda reading.
Last edited by EvoBroMA; Feb 27, 2008 at 11:44 AM.
Feb 27, 2008, 11:37 AM
#8151
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Edit: You guys are vultures with this poor guy's car! Already ripping it apart on him before he even knows what's happening with it!
Last edited by Marshall O; Feb 27, 2008 at 11:42 AM.
Feb 27, 2008, 02:17 PM
#8158
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Feb 27, 2008, 02:26 PM
#8159
Wow man that REALLY sucks. They may try to total it but it all looks fixable. From those pics i see a new front/rear bumper/ tailight, fender, lip, rear quarter, wing, maybe a wheel or two, maybe a control arm. It depends how much it is accessed at. A lot of the expensive stuff looks like it is fine (engine, drive train, interior stuff)
I have to say i am not happy to see the advans on there. They are pretty much a guaranteed accident in the winter.
I have to say i am not happy to see the advans on there. They are pretty much a guaranteed accident in the winter.
Feb 27, 2008, 02:28 PM
#8160
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Wow man that REALLY sucks. They may try to total it but it all looks fixable. From those pics i see a new front/rear bumper/ tailight, fender, lip, rear quarter, wing, maybe a wheel or two, maybe a control arm. It depends how much it is accessed at. A lot of the expensive stuff looks like it is fine (engine, drive train, interior stuff)
I have to say i am not happy to see the advans on there. They are pretty much a guaranteed accident in the winter.
I have to say i am not happy to see the advans on there. They are pretty much a guaranteed accident in the winter.
funny thing is, i just got it out of the shop like 3 days before this happened, a damn parked mini van jumped out in front of me on christmas night........... poor car, all kinds of bad luckand the advans would be the reason it wasn't.........shouldn't have been driven in the snow............but she insisted on going to dance class in it