This may seem like a dumb question but I have been unable to find the answer.
Is the duty cycle expressed as a percentage of time the injector is activated.
If so, how can I get a duty cycle of over 100%
Injector Duty Cycle
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Read the manual to see if your question is answered there before posting. Many users will not reply if the answer is already available in the manual.
If your question is about troubleshooting, configuration, or tuning, you MUST include your processor type (MS-I or MS-II) and code version in your post. If your question is about PCB assembly or modifications, you must also include the main board version number (1.01, 2.2 or 3.0).
If you have questions about MS1/Extra or MS2/Extra code configuration or tuning, please post them at www.msextra.com Such questions posted here will be moved to: a temporary MSextra sub-forum, where they will be removed after 7 days
The full forum rules are here: Forum Rules, be sure to read them all regularly.
Injector Duty Cycle
Trumpy
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efahl
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Yup, dumb question. Next!
Just kidding. I think it's in the FAQ, but the reported duty cycle is "commanded" and not the physical duty cycle. For example, say that MS runs through its calcs and comes up with a 12 ms pulse width, but that the engine is running at an RPM with 10 ms cycle time. This would result in a reported 120% duty cycle, which although not physically possible, is still very diagnostic in that you know your injectors are too small, or that your injection pattern is wrong, or fueling values are incorrect by some quantifiable amount.
Eric
Just kidding. I think it's in the FAQ, but the reported duty cycle is "commanded" and not the physical duty cycle. For example, say that MS runs through its calcs and comes up with a 12 ms pulse width, but that the engine is running at an RPM with 10 ms cycle time. This would result in a reported 120% duty cycle, which although not physically possible, is still very diagnostic in that you know your injectors are too small, or that your injection pattern is wrong, or fueling values are incorrect by some quantifiable amount.
Eric
efahl
Thanks. I revisited FAQ and could not find the info required.
Lets see if I have got this correct.
If I show a Duty Cycle of 110% at a particular RPM/kPa, Then the injector is 'on' 100% of the time and is in fact underfueling by 10% (not taking into account the fact that it should be kept below about 80%)
Thanks. I revisited FAQ and could not find the info required.
Lets see if I have got this correct.
If I show a Duty Cycle of 110% at a particular RPM/kPa, Then the injector is 'on' 100% of the time and is in fact underfueling by 10% (not taking into account the fact that it should be kept below about 80%)
Trumpy
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efahl
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It might be underfueled by 10%, or maybe the tune is 10+% too rich, you need to figure that out. Early on in tuning a motor it is not unusual to have things way too rich resulting in duty cycles over 100%; these will go away as soon as you get the tune in the ballpark, assuming you did the up-front math and have properly sized injectors.
Eric
Eric