Duty-cycles exclusively for Jim W!

Hi Jim!

Special message to you: When you define injection-duration in pure time, like mS (that is milliseconds, 1/1000 of a second) you know nothing about the total time available for injection. Don't you see? If a 4-cyl engine with sekvential injection runs at 4000rpm (66,6rps), you'll have a total time of 30mS available between each injection pulse. In other words, this sets a limit on the pulsewidth available. If you instead use the term duty-cycle at 4000rpm, you'll know exactly both the on time and off time of the injector. If at 4000rpm you have a duty-cycle of 95%, means injector on 28,5mS and off 1,5mS. So, don't tell me that duty-cycles isn't possible to use, it's far better than just using mS figures. End of lesson.

By the way, since I know Backyard Mech. are reading this aswell, I'd like to say: I believe I earn the same amount of money in an hour, as you do in a day. Have a nice day.

Reply to
stefan.toftevall
Loading thread data ...

Hurricane is back!

Reply to
aarcuda69062

Compute it however you want... but I fail to understand this overwhelming desire you have of adding steps to the process.

In the field, we use mS exclusively.... Look at it this way, the PCM knows how much air is entering the cylinder.... the PCM also knows how much fuel will be injected for each millisecond of "on" time... and the PCM has a target called mass fuel desired.... No need for unecessary computations nor the waste of processor cycles. Simple... here's the "trigger", we turn on now and off after so much time.

FWIW, if you are nosing over at the top end, why not consider a higher flow injector. Or is that too simple, too?

If you earn in an hour what I earn in a day, you could buy yourself a decent engineer...

Reply to
Jim Warman

Yep, whatta load of gobbledygook crap!

  1. the number of cyls is moot, you're talking about 1 cylinder per injector.

  1. Fuel delivered per open time depends on differential pressure (fuel v manifold) x orifice size plus latency of the solenoid action.

  2. Open time depends on air moved per intake stroke in cfm

I see nothing there that requires knowledge of duty cycle OTHER than need to find maximum rpm available at Fuel Pressure x orifice x air mass at stoich.

In other words, WTF are you going to do with duty cycle? All you need to do is know the open time is in the design params for power @ rpm... unless you intend to use it to diagnose FPR and Fuel Pump operation.

I'll just keep diagnosing my OWN cars, thank you.

- - - - - - - -- -

Ten years ago, Hast, I made more in a week than you made in a month.. or maybe two.. but some folks retire.

Which also means nothing when it comes to understanding how things work.

Which he doesnt.

Reply to
Backyard Mechanic

And with a spell checker this time! Bob

Reply to
Bob

Hey Bob, whatcha been up to?

Saw on the news that there were some funnel clouds up in Minnesota, none got too close I hope. We had two down here today, but by the time I got the truck on the road, they were gone (damn). Is the snow cover gone up there yet? ;-) Been dodging the heat down here, the Raytek said it was 104* yesterday, damn glad the shop has A/C.

Reply to
aarcuda69062

Jim Warman skrev:

Ok, the hurricane is back again, (thanks for that) and in fact without a spelling checker, since I don't have one, but might need one. (thanks for bringing it up, Bob) Still, I succeed to replace the batteries in my remote, and I also get the polarity right when changing my light bulbs...not everyone can do that! ........

After all, my intention wasn't to start a war, my time is much too valueable for that.

No use keeping the discussion on.

Regards

Reply to
stefan.toftevall

Been hot and mostly dry here, as for snow.... what the hell is that? We haven't had shit for snow since I got into snowmobiles back in 98.

Just bought 12 acres in the country last weekend so I will be pretty busy for the next couple of years. The place has a ton of potential but lets just say it's a little "rough" the way it stands...lol. On top of that it looks like I will probably be relocating the business to somewhere not quite so flood prone in the near future.

So you're one of those guys that actively chases tornados? I'm just about always outside when the weather turns bad.... we had one touch down a couple of miles away maybe 2 years ago and it was like a block party. Everyone standing in the street watching the funnel cloud. Of course it was obviously moving away from us.... no way in hell would I get in my car and try and catch it! I'll gladly leave that to you... Bob

Reply to
Bob

MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.