Cam sensor and ignition modifications

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PrecisionBoost
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Re: Cam sensor and ignition modifications

Post by PrecisionBoost »

PrecisionBoost wrote:Pulse width is fixed between two identical engines running the same air fuel ratio with two different injection modes ( batch vs sequential ).
ls400x wrote: Agreed, conditional on there being one injection event per cycle and all other variables the same. You contradict yourself further down though.
PrecisionBoost wrote: Pulse width is the TOTAL time an injector is on during a cycle ( intake, compression, power, exhaust ) which is 2 revolutions of the crank.
ls400x wrote:No, it's the time duration of the injector circuit being closed. It is independent of being in a cycle.
The pulse width in a 4 stroke engine is the time the injector is energized over 720 degrees, which is one cycle, which is 2 revolutions of the crank.

Based on what your saying the "pulse width" is not dependent on anything, which is dead wrong.


I think your confusing pulse width as it may apply to a standard square wave where we are applying a given frequency referenced to the zero crossing.

In those cases, the period is 1 second / frequency of oscillation, where you will then have a fixed pulse width of known value within the period.


This is not a simple waveform, the pulse width of an injector is referenced to a "period" of 720 degrees of crank movement, which changes with RPM

They use the total injector on time during the 720 degrees to define injector pulse width simply because they only want to figure out how much fuel was injected.
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PrecisionBoost
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Re: Cam sensor and ignition modifications

Post by PrecisionBoost »

ls400x wrote: None of the above is true. Same thing as the previous comment. There is one continious on period and one continious off period per cycle (720 crank degrees) batch or sequential.
This is a 60-2 reluctor wheel setup, all injection and ignition events are timed from the missing notches

In sequential the injectors fire off the reluctor wheel's timing mark only if the cam sensor aligns to signal an intake stroke

In batch the injectors fire a set number of degrees past the reluctor wheel's timing mark no matter what.

That is to say there are two separate injection events during a full cycle of 720 degrees.


You saying that there is just one injector event per 720 in batch is like saying there is just one firing of the ignition during 720 degrees.

Plain and simple... in sequential there is one injector event every 720 degrees... in batch there is one injector event every 360 degrees.

If you do not have a cam signal reference you can't inject once, you have to do it twice.

What if you started up the engine and it allways injected on the power stroke of the cycle ?

Then you would be dumping fuel into a closed valve with zero airflow.


In batch it's firing once into the closed intake valve and again 360 degrees later when the intake valve is open.
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PrecisionBoost
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Re: Cam sensor and ignition modifications

Post by PrecisionBoost »

ls400x wrote: None of the above is true. Same thing as the previous comment. There is one continious on period and one continious off period per cycle (720 crank degrees) batch or sequential.
This is a 60-2 reluctor wheel setup, all injection and ignition events are timed from the missing notches

In sequential the injectors fire off the reluctor wheel's timing mark only if the cam sensor aligns to signal an intake stroke

In batch the injectors fire a set number of degrees past the reluctor wheel's timing mark no matter what.

That is to say there are two separate injection events during a full cycle of 720 degrees when batch injection is used


You saying that there is just one injector event per 720 in batch is like saying there is just one firing of the ignition during 720 degrees.

Plain and simple... in sequential there is one injector event every 720 degrees... in batch there is one injector event every 360 degrees.

If you do not have a cam signal reference you can't inject once, you have to do it twice.

What if you started up the engine and it allways injected on the power stroke of the cycle ?

Then you would be dumping fuel into a closed valve with zero airflow.


In batch it's firing once into the closed intake valve and again 360 degrees later when the intake valve is open.[/quote]
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