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Old 01-27-2020, 05:21 AM   #38 (permalink)
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Originally Posted by bradlington View Post
A concern I have with the mpguino is the use of parameters.
The code does not take into account load .

Example my vehicle being a 2.5 l engine on idle with no load has a pulse width of 2,5 ms.
If I enter this into the code , I could get a reasonable accurate measurement .

The moment I have load such as headlights or going up an incline or wot , the pulse width is then varied according to the map being used at the time .

So for average it may turn out as an accurate account but for load variations I do not see it being that accurate .
I am yet to connect mine up and see for myself , but am assuming the code does not measure the pulse width as part of the code and purely going on pulses per minute for its base calculation.
oh no sir, the MPGuino is extremely accurate.

the MPGuino measures pulse width of the injectors. it also counts injection pulses per second for an RPM number, but this is secondary.

A typical injected car has a fuel rail with a constant pressure maintained by a regulator on the fuel return side. this is also balanced by the pressure differential felt on the manifold side of the injector. This creates an exact known quantity of fuel for given pulse time that the cars ECU can then manage. The ECU adjusts the pulse width of the injector to adjust how much fuel is added per cycle of the cylinder as the load changes. the MPGuino measures this signal in microseconds.

It has shown itself to be extremely accurate. My 100 series Landcruiser takes over 120L to fill, and each time it has been within 0.5L of what the MPGuino thinks I've used. Aha I believe this to be an inaccuracy of how many clicks I do on the nozzle myself though aha

The only thing the MPGuino cannot compensate for is fuel density through change in fuel temperature. But this would only be if the average temperature of the fuel has deviated by more than say 20DegC since calibration, and this hasn't proven to be an issue in real use. Even on a hot day and cool night, the fuel itself deep within the car doesn't have time to change temperature all that much, and generally remains somewhere in the middle.

Last edited by abbalooga; 01-27-2020 at 05:28 AM..
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