Re: Puma board for FreeEMS
Posted: Mon Jul 25, 2011 7:46 pm
With "smart" injector driver I mean a driver which monitors the current and uses PWM control method to limit the peak and hold currents, just like TLE6270 does the job. In fact techniques which are used for GDI would be very beneficial for non-direct injectors, too:
Seems that there would be some common interest at least with this injector controller. I think I could share the CDI controller design (to be used in FreeEMS HW designs) but first it needs to be tested out with few prototypes. Alternatively CDI controller could be provided as an external ignition driver, too, if someone wishes to use traditional methods.
If there are more interested people regarding CDI and/or injector driver maybe we could even create own (scrumm) workshops - as well as dedicated discussion threads - from these activities?
Fred: I was positively surprised that FreeEMS development uses agile methods. That is impressive for this kind of "unorganized" organisations because even my employer doesn't use it although our company calls themselves engineering/consultant company, while employing over 1000 designers in several countries. Very impressive, indeed!
- Larger operating voltage (80Vdc) for peak current driver results faster and more precise injector opening time --> less variation between injectors' opening times
- Once peak current is achieved, hold current can be created from 12Vdc resulting lower PWM fequency (than 80Vdc would result)
- When injector shall be closed, raising the clamp voltage results faster zero-current decay. Usually the designs I've seen (e.g. MS) have used 36V clamp voltage which is still better than 12V, but higher the better. This why TLE6270 uses 87V clamp voltage.
- Usually injectors or other solenoids are happy with 4:1 current ratio for peak/hold values, while most aftermarket injector controllers have user-selectable options such as 2A/0.5A and 4A/1A.
Seems that there would be some common interest at least with this injector controller. I think I could share the CDI controller design (to be used in FreeEMS HW designs) but first it needs to be tested out with few prototypes. Alternatively CDI controller could be provided as an external ignition driver, too, if someone wishes to use traditional methods.
If there are more interested people regarding CDI and/or injector driver maybe we could even create own (scrumm) workshops - as well as dedicated discussion threads - from these activities?
Fred: I was positively surprised that FreeEMS development uses agile methods. That is impressive for this kind of "unorganized" organisations because even my employer doesn't use it although our company calls themselves engineering/consultant company, while employing over 1000 designers in several countries. Very impressive, indeed!