Injector Flowrate Testing

chadjmccolm commented 6 years ago

Context

We need the precise injector flow rate to calibrate our electronic fuel injection.

Outcomes

We want:

[x] max flowrate (cc/min)
[x] dead time (ms)

chadjmccolm commented 6 years ago

This will be handled by testing flow by triggering with a 12V output on a power supply and through the Microsquirt using Tunerstudio's test mode as described here.

chadjmccolm commented 6 years ago

At 50psi and continuous flow:

Volume	Unit	Time	Unit	Flowrate	Unit
99	cc	12.5	s	475	cc/min
100	cc	12.014	s	499	cc/min
99	cc	12.6	s	471	cc/min
			average	482	cc/min

chadjmccolm commented 6 years ago

I decided to change my approach. I set up the injector with triggering off the microsquirt and varied pulse width and number of squirts to get a measurable amount of fuel in the graduated cylinder and plotted.

Data

Pulse Width (ms)	Pulses	Volume (mL)	Volume/Pulse (cc)
10	200	14	0.07
15	200	22	0.11
20	200	30	0.15
2	1500	17	0.011333333
7	400	19.5	0.04875
13	200	19	0.095
3	500	10	0.02
5	500	17	0.034

I used Excel's linest function to determine the pulse width and flowrate from this graph with the error.

Regression

Metric	Value	Value	Metric
ms/cc	130.6922	0.568249	Dead Time (ms)
Error	1.25075	0.101405	Error

This gives a dead time of 0.57ms plus minus 0.10ms and a flowrate of 459cc/min plus minus 4cc/min.

Future Work

This test should be repeated at different voltages to determine how the dead time changes with voltage. My workbook is in Drive\Mechanical\2017-2018\Projects\Injector Testing

UVicFH / Home