The trick is the very well mappable boost-target.
Since the solenoids people kept finding were on/off type with 20..30 Hz max frequency, the original high frequency softpwm implementation had to be changed.
- pid (userspace) calculations. Ideally best to calculate pid just before actuation (eg. always before falling edge - since the rising edge timing varies).
- actuation (userspace or interrupt or combo)
- DROPPED: actuation of both edges in interrupt with EventQueue? the same way as OutputTrigger mst..msp..msq..
- pid() calculation called from (userspace) vems.c mainloop every N msec using softelapsed(). We do the activation edge right from there. The other edge is scheduled via eventqueue (unless the output is railed at 0 or 100%). Take care with duty overflow (similar way as for injection).
PID parameter tuning of such a system is not trivial.
- I want to do some measurements on the valve and restriction on the table. Especially since it's almost impossible to get proper datasheet from solenoid valve manufacturers.
- I cannot measure the wastegate's effect without the engine though
- compressor supply
- solenoid valve
- noise (another restriction and pneumatic switch?) to disturb the controller
- pressure sensors
- controller (GenBoard/VerThree)
- el. connections
- pneumatic connections
Pneumatic valve flowbench setup
My tire inflating compressor eats 11..12A from 12V supply, so I had to use a battery for this.
- pressure container
- adjustable blow-off valve (red cap near the gauge)
- MPX700A (inside the 1" T)
- MPX4250AP (inside the 1" T)
- unfortunately I lost the paper that has the pinout of the cable: the 1" T with absolute pressure sensors was used in an earlier experiment to calibrate MPX700A at several temperatures
Playing with filling and charging a dry battery
I got a dry Lead-acid battery that I should fill and charge for the experiments. Looking for the sulphuric acid concentration to fill up originally with. I'll have to slowly charge and discharge a few times.
- google: lead acid battery fill sulphuric acid concentration charge
- http://www.du.edu/~jcalvert/phys/lead.htm#Batt history and "electrolyte of dilute sulphuric acid of specific gravity 1.28. This is a 37% solution, with 472.5 g/l of H2SO4. At full discharge, the electrolyte is of specific gravity 1.05, an 8% solution containing 84.18 g/l of acid. Both plates are coated with PbSO?4"