CERITAREZA: PEDIH~~~

Calculate injector pulsewidth from airflow

First the CPU determines the air mass flow rate from the sensors - $M a s s a i r / M i n u t e$ . (The various methods to determine airflow are beyond the scope of this topic. See MAF sensor, or MAP sensor.)

$\frac{Mass_{air}}{Minute} \times \frac{Minutes}{Revolution} \times \frac{Revolutions}{Stroke} =\frac{Mass_{air}}{Stroke}$

M i n u t e s / R e v o l u t i o n

is the reciprocal of engine speed (RPM).

The term

R e v o l u t i o n s / S t r o k e = 1 / 2

, whether it's a four stroke or a two-stroke engine.

$\frac{Mass_{air}}{Stroke_{intake}} \times \frac{Mass_{Fuel}}{Mass_{Air}}=\frac{Mass_{Fuel}}{Stroke_{intake}}$

M a s s F u e l / M a s s A i r

is the desired mixture ratio, usually stoichiometric, but often different depending on operating conditions.

$\frac{Mass_{Fuel}}{Stroke_{intake}} \times \frac{1}{Mass_{Fuel}/Minute} =\frac{Minutes}{Stroke_{intake}}=Pulsewidth$

1 / (M a s s F u e l / M i n u t e)

is the flow capacity of the injector, or its size.

Combining the above three terms . . .

$\frac{Mass_{air}}{Minute} \times \frac{Minutes}{Revolution} \times \frac{Revolutions}{Stroke} \times \frac{Mass_{Fuel}}{Mass_{Air}} \times \frac{1}{Mass_{Fuel}/Minute} = Pulsewidth$

Substituting real variables for the 5.0 L engine at idle.

* $0.55 \frac{lb}{min} \times \frac{1 min}{700 rev} \times \frac{1 revolution}{2 strokes} \times \frac{1}{14.64} \times 2.5\frac{min}{lb} = 6.7 \times 10^{-5} min = 4ms$

Substituting real variables for the 5.0 L engine at maximum power.

* $28 \frac{lb}{min} \times \frac{1 min}{5500 rev} \times \frac{1 revolution}{2 strokes} \times \frac{1}{11.00} \times 2.5\frac{min}{lb} = 57.9 \times 10^{-5} min = 35ms$

Injector pulsewidth typically ranges from 4 ms/engine-cycle at idle, to 35 ms per engine-cycle at wide-open throttle. The pulsewidth accuracy is approximately 0.01 ms.

* RUMUS ENGINE FUEL INJECTION(EFI) kalah subjek math+science tech...huh~~ p/s : mereng seketika..huhuhuuu~~