WUE and ASE. Does 1 temperature mean 2 things?

[landybehr]

Hi,

I make progress in tuning the warm-up. Which is much more demanding than hotstart and enigne-running. As I do a lot of short distance driving and many cold starts please excuse me for stirring up something obvious to others. I bother about too much enrichments and dilution of oil and adverse effects like that.

Now I started with get it running when really cold (say 0°C) and then adjust the WUE bins on the way to operating temperature, doing so by keeping them as low as possible (with only one eye at AFR gauge, guiding me at being no leaner than when warm) without any signs of surging or powerless feeling.
That way I got a 20°C WUE bin of, say, 150%. Now if I do something different - I start the engine one morning when the coolant is 20°C warm already, I realize my former WUE is way too lean. And the engine will die after 2sec. One restart and it should run, but not very nice for a couple of more seconds.


!! So it seems to make a difference whether the engine is started with a certain coolant temp., or it reaching the same temperature after having run for some time.
I believe that is because the combustion chambers have been warmed up in the latter case for a while which aids evaporation or the like

>> The defaults have the ASE taper time for a certain amount of cycles, in the range of 150-300 cycles. Wouldn´t it be smart to make the WUE bins as low as possible (to avoid running unnecessarily rich while running up through the WUE bins) and on the other hand help the engine starting by prolonging the ASE taper time. That way the enrichment would only occur during the first " quarter or half a minute" of warmup.
But I always respect the default values. They have vast amount of experience behind them. Thought I asked for why things have been designed the way they are. At the moment I realize that staying close to the default ASE and trying to keep low WUE%´s does not work.

[66fb]

landybehr,

I've experienced your results also and I agree with your observations about the two "different 20*C" starting points.

Experimenting on the stimulator and data logging with ASE set at 300 cycles gives approximately 9 seconds of enrichment at ~ 800 rpm. As you said, try increasing this time beyond the suggested setting. Each engine and setup is a bit different. I've found that disabling ASE for hot restarts works fine.

I think the WUE bins should be set to give the AFR you want the idle to be. You didn't say what, if any, type of IAC you are using. Coordinating the idle air step setting at a particular temp bin with the enrichment % in the Warm Up Wizard at the same temp bin will help keep the AFR close to where you want it.

[landybehr]

Hi,

1) I asked elsewhere and have learnt that one ASE cycle is finished after 2 crankshaft revolutions. So at 600Rpm with 300cycles that would mean 1minute of enrichment. Isn´t that true ??

2) the biggest number I could dial in would be "999" I guess ? (which looks plenty anough for me)

3) how is "hot start" defined ? In other words, under what conditions do I feel a difference when ASE-on-hotstart is disabled ?

Many thanks!