DCT software update

[SteveThackery 3,090]

4 hours ago, Griff said:

 

I'm not sure that the creep is deliberate, especially now that it has gone from mine after the recalibration. 

 

 

Sorry, I made a mistake: the system uses something called "weak creep", but in theory that should only occur at the point the throttle is opened.

 

See here: https://www.hondarandd.jp/

 

The paper you want is "Development of Dual Clutch Transmission for VFR1200F", and on page 13 you will find an explanation of weak creep.

 

 

 

Edited May 19, 2018 by SteveThackery

[SteveThackery 3,090]

4 hours ago, Griff said:

 

I am wondering if you should consider a change of oil brand just to eliminate that as a possible cause of your issue. I have noticed that while various brands specify a particular viscosity say 10/40, I suspect that not all of them are actually exactly the same viscosity and indeed the different manufacturers have various differing properties that might affect such a sensitive system in different ways. Just a thought. . 

 

 

Yes, that was my conclusion, too.  I think the oil is too thick when cold.  As I say, when it's warmed up it is perfect.  Of course, you have to do the calibration when warmed up, so the system doesn't "know" anything about the cold oil viscosity.

 

I'm planning to wait until it's had its final dealer service (at the end of the warranty) and then I'll put my own choice of oil in.  Or actually, I'll probably sell it before then.

[SteveThackery 3,090]

4 hours ago, embee said:

Out of interest, what oil are you using Steve?

I've found a 50/50 mix of Castrol Power1 (semi-synth) 10/30 and 10/40 works very nicely in my 700 Integra. According to the spec sheets their oils are generally near the bottom limit for the viscosity bands, so although not strictly technically correct the mix should give something effectively nearer a mid 10/30 spec. I do however also have an oil/water cooler (heat transfer device anyway) fitted which helps speed up the oil warm-up a bit and ought to stabilise the oil temp a bit.

 

Embee, as it's in warranty I've had the Honda dealer do the service, and I believe they use Honda's own brand of oil.  I've no idea who actually makes it for them.

 

I think your idea is good - if I keep the bike long enough I will definitely try some different oil brands.

[Griff 1,556]

I am wondering if there is something in the 2017 software that changes the clutch engagement point on a cold motor ?   I was a little anxious on my first cold start this morning subsequent to recalibration, that the cold performance of the clutch might differ. However it was the same as usual. The cold clutch engagement point is considerably higher in the rev range to the fully warmed up one and that was the same as usual.  

[SteveThackery 3,090]

13 hours ago, Griff said:

I am wondering if there is something in the 2017 software that changes the clutch engagement point on a cold motor ?   I was a little anxious on my first cold start this morning subsequent to recalibration, that the cold performance of the clutch might differ. However it was the same as usual. The cold clutch engagement point is considerably higher in the rev range to the fully warmed up one and that was the same as usual.  

 

According to the research papers, it certainly knows about the oil temperature and takes it into account.  Exactly what it does with the information isn't clear, but I think it will be to handle the greater viscosity, and thus more sluggish responses from the clutches.  Just a guess, though.

[Griff 1,556]

23 minutes ago, SteveThackery said:

 

According to the research papers, it certainly knows about the oil temperature and takes it into account.  Exactly what it does with the information isn't clear, but I think it will be to handle the greater viscosity, and thus more sluggish responses from the clutches.  Just a guess, though.

 

Well from what I can see with regard to the cold behaviour of my bike Your guess is clearly correct. 

[embee 7,288]

3 hours ago, SteveThackery said:

 

According to the research papers, it certainly knows about the oil temperature and takes it into account.  Exactly what it does with the information isn't clear, but I think it will be to handle the greater viscosity, and thus more sluggish responses from the clutches.  Just a guess, though.

Agree.

The calibration of clutch engagement is going to be somewhat empirical I think, while it takes temp (viscosity) into account and is obviously calibrated accordingly it can't know what the exact oil viscosity is for the oil in use, so is going to be an approximation. I would imagine Honda have calibrated using different oils and have come up with a best fit solution. The system does know the various shaft speeds relative to engine and road speed, so I would imagine there's some form of feedback system to regulate the application of pressure to the clutches taking this into account (just my guess but I can't imagine not doing it). The viscosity will affect the clutch friction to some extent and also the rate of change of oil pressure in the clutch actuators, so it's bound to behave somewhat differently at different temps, the engineers' task is to make something which works acceptably under various conditions not necessarily perfectly under all conditions.

The initialisation procedure enables the system to establish the biting points for the clutches as fitted, thus slight production variations can be accommodated. This is free and simple so is well worth doing occasionally and especially if the shifts are harsh or the take up from standstill is overly sharp or sluggish. Mine had got rather "sudden", tending to be a bit all-or-nothing when moving off from standstill. A recal sorted that.