TPS Acceleration Enrichment - err WTF
Newbie
Joined: Jun 2009
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From: Somewhere over the 9th floor
Found a clue:
"Some prior acceleration fuel enrichment systems respond to an engine acceleration transient by merely extending the fuel control pulse durations of the base engine synchronous fuel control pulses that are provided by the steady state fuel pulse control circuit. These acceleration enrichment systems typically do not perform in a satisfactory manner in that they do not react fast enough to an engine throttle position increase to provide additional fuel when it is needed by the engine. The result is hesitation of the engine during acceleration because of an excessively lean fuel mixture. Some other acceleration fuel enrichment systems attempted to solve this problem by developing asynchronous fuel control pulses which immediately added fuel to the engine upon the detection of a substantial increase in throttle position. "
From:
http://patft.uspto.gov/netacgi/nph-P...ery=PN/4490792
"Some prior acceleration fuel enrichment systems respond to an engine acceleration transient by merely extending the fuel control pulse durations of the base engine synchronous fuel control pulses that are provided by the steady state fuel pulse control circuit. These acceleration enrichment systems typically do not perform in a satisfactory manner in that they do not react fast enough to an engine throttle position increase to provide additional fuel when it is needed by the engine. The result is hesitation of the engine during acceleration because of an excessively lean fuel mixture. Some other acceleration fuel enrichment systems attempted to solve this problem by developing asynchronous fuel control pulses which immediately added fuel to the engine upon the detection of a substantial increase in throttle position. "
From:
http://patft.uspto.gov/netacgi/nph-P...ery=PN/4490792
Last edited by Windstorm; Nov 6, 2012 at 07:13 AM.
Newbie
Joined: Jun 2009
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From: Somewhere over the 9th floor
OK so sarcasm doesn't come across very well on the internet. Look at the first image and read the first paragraph:
"Fuel injection to each cylinder is done by driving the injector at optimum timing while it is in the exhaust process based on...blah,blah, blah"
What I was trying to say, is that it seem like translation is the issue. Unless there is a massive delay between when the ECU says "fire" and when it actually occurs.
As for "tau" we have tables that already account for this, specifically MAT v MAP.
"Fuel injection to each cylinder is done by driving the injector at optimum timing while it is in the exhaust process based on...blah,blah, blah"
What I was trying to say, is that it seem like translation is the issue. Unless there is a massive delay between when the ECU says "fire" and when it actually occurs.
As for "tau" we have tables that already account for this, specifically MAT v MAP.
Cool, I didn't know what those tables were - thanks!
Interesting discussion. So apparently big injector guys are spewing way too much fuel for these events without injector scaling?!?
Sounds like someone cut a corner at Mitsu by not using the scaling. But of course I'm trying to give them the benefit of the doubt and think logically about why they might not adjust this pulse based on injector scaling.
The only thing I can think of is that the amount injected does not have to be precise so for the given range of injector sizes they plan to use it's not worthwhile to adjust? Obviously with 2100cc's you might care
Sounds like someone cut a corner at Mitsu by not using the scaling. But of course I'm trying to give them the benefit of the doubt and think logically about why they might not adjust this pulse based on injector scaling.
The only thing I can think of is that the amount injected does not have to be precise so for the given range of injector sizes they plan to use it's not worthwhile to adjust? Obviously with 2100cc's you might care
Thread Starter
Joined: Feb 2007
Posts: 9,486
Likes: 67
From: Melbourne, Australia
yeh, keep in mind it doesn't even take into account the air going into the cylinder (by load, map, airflow, whatever)
so it really is just a mechanism to maintain the wetness of the runner.
I think anyone using larger than normal injectors can benefit from modifying this - just like you would do for cranking enrichment.
I will get a better scaling (in IPW ms) for that last table, and there is also a minimum (or maybe max) IPW as well..
so it really is just a mechanism to maintain the wetness of the runner.
I think anyone using larger than normal injectors can benefit from modifying this - just like you would do for cranking enrichment.
I will get a better scaling (in IPW ms) for that last table, and there is also a minimum (or maybe max) IPW as well..
Newbie
Joined: Apr 2009
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From: Texas
This is what I see when I read this.
Evolving Member
Joined: Jan 2009
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From: Singapore
Hi David, would tweaking these tables help in fixing my "momentarily lean condition" during sudden acceleration as a result of my aggressive MIVEC maps.
Or should I be looking at the "Load Accel IPW Enrichment" tables you posted a while back?
Or should I be looking at the "Load Accel IPW Enrichment" tables you posted a while back?
Last edited by RS200Z; Nov 10, 2012 at 04:59 AM.
Thread Starter
Joined: Feb 2007
Posts: 9,486
Likes: 67
From: Melbourne, Australia
check my new post, your load might not be ramping up quick enough, changing the ramp tables will/might help!
https://www.evolutionm.net/forums/ec...ated-maps.html
https://www.evolutionm.net/forums/ec...ated-maps.html
EvoM Guru
iTrader: (50)
Joined: Mar 2006
Posts: 9,675
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From: Tri-Cities, WA // Portland, OR
hey dave, "accel" enrichment logic also exists in the pre-10 code. bez identified it a while ago, and i worked the tables in more detail after that. the pre-10 code is purely a mechanism to provide a compensation for small changes in throttle position. the relative contribution to the total fuelling is quite small (i've logged it) and only active at relatively low loads and throttle positions.
https://www.evolutionm.net/forums/ec...l-options.html
see second post.
https://www.evolutionm.net/forums/ec...l-options.html
see second post.
Question, shouldnt the ECT based adder and RPM based adder be set as a percentage? It seems it would make more sense that way rather than just a random value
Also, what pecentage scaling? (Percent255 or Percent 300) Percent255 seems to be the most logical
Also, what pecentage scaling? (Percent255 or Percent 300) Percent255 seems to be the most logical
Last edited by chetrickerman; Jan 1, 2013 at 08:08 AM.