CoreyG Posted August 21, 2022 Share Posted August 21, 2022 Hi everyone, I have thrown together a simple web application that might be useful for people working on injector scaling. As has been discussed many times on this forum, changing the low slope / breakpoint / deadtime offset affects the amount of fuel delivered at higher pulse widths. This app provides you with the ability to adjust these values with a slider to help figure out the optimal injector scaling (or at least as close to optimal as possible). The site is currently hosted at https://injectorscaling.fly.dev/ Fill in the information in the attached spreadsheet and upload it to the site to play around. Unfortunately there is a 30 second time out with fly.io (that I can’t change), so you might need to refresh your page every so often. The top plot shows you a comparison of the original injector settings (black line) and the new settings (red line) – based on the sliders of the left. The dashed horizontal lines show the breakpoint (change between low and high slopes). The vertical dashed lines show the injector minimum pulse width (which isn’t really used in this app). The second plot shows what (approximate) effects these changes will have on the amount of delivered fuel. I’m not quite happy with this part, so I’m happy to have suggestions/comments. However, you can think of this like so: the PCM asks for a certain amount of fuel and uses the first plot like a look up table (draw a line in from the y-axis until you hit the black line, then draw a line down to the x-axis to see the pulse width required). To make this plot, I then draw a line up from that pulse width until we hit the red line, then draw a line across to the y-axis. This would be the amount of fuel that is delivered (assuming all of the new values are actually correct). The difference in expected vs delivered is converted to a pseudo long-term fuel trim and shown on the graph. Note: this could also be shown for pulse width instead of fuel on the x-axis. There is another plot below those two that show the injector deadtime vs battery voltage. I allow you to change the battery voltage on the slider, but it doesn’t qualitatively change much in the first two graphs. Rather than change all the values of this, I have applied a simple “offset” that just adds or subtracts a fixed time to the injector deadtime. You can see that it raises or lowers the entire curve and can make a large difference in the first two plots. This is just a first prototype. I was hoping to have more features before releasing it, but I haven’t made much progress due to time constraints. I have another app for viewing the spark advance table under different engine conditions e.g. sliders to change ECT, ACT, Lambda, catalytic converter temp etc. The excel file has 18 tabs (not all of which are needed for all situations), so it isn’t the friendliest thing to use. I’ll post when this site is up. Injector_scaling.xlsx 2 1 Quote Link to comment Share on other sites More sharing options...
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