Uni Honours Project - quick survey question for research :)

(This may apply more to the TT/single guys as it will be more noticeable. Though NA owners are allowed to chime in to feel important too )

Anyway...

I'm currently doing my Mechanical Engineering dissertation. My topic is torque converter design and modelling.

An aspect which I am considering when designing a torque converter is ambient temperature. The way I'm integrating this is by stating that colder air = denser air = more oxygen = more fuel = more power/torque.

The relevance of this is that more power/torque through the engine gets put to the impeller of the torque converter. This then transfers to the turbine side of the torque converter at a higher value than it would be at warmer temperatures, putting more power through the remainder of the transmission and thus putting more power to the ground, possibly breaking traction.

With this higher value entering the torque converter from the crank (engine) side, the unit is more susceptible to being over-worked and - consequentially - damaged.

In short, if you could please complete the poll and (if you have time) leave a short comment detailing your experience of colder temperatures on traction and power output (compared to hotter temperatures with no change to your car's spec).

Thank you very much

James

*EDIT* of course the amount of temperature variation will affect the amount of output variation. Just a general consensus through experience is required!

Please note - despite the project concerning the torque converter, experiences from members with manual transmissions are gladly welcomed too.

Cheers

The definitive results of this question would be through testing and not via 'opinion'?

With cooler ambient temps this would also have an effect on the chemical/physical reactions between the tyre rubber compound and the road surface.

So although you may have more torque from the engine reaching the wheels, it may also be the case that your tyres may not be producing the traction that you had in higher ambient temps.

I've voted. In case it helps I was talking to Dibley at Austec, and he commented how the gearboxes he'd broken had been on cold nights. Think a few others may have experienced the same too (I know I also have)

The definitive results of this question would be through testing and not via 'opinion'?

 

With cooler ambient temps this would also have an effect on the chemical/physical reactions between the tyre rubber compound and the road surface.

So although you may have more torque from the engine reaching the wheels, it may also be the case that your tyres may not be producing the traction that you had in higher ambient temps.

Yes, direct testing will give a definitive proof as to the occurrence of this. Having a further source through the experiences of others helps solidify the conclusion formed regarding the prior tests.

And also yeah, I have considered the road surface temperature changing with differing temperatures and will be accounting for that. Separating the power increase/traction loss segments, road temperature isn't affecting the power made at the engine, so I will consider the two parts one after the other and then amass the info as required.

I'll discuss the traction aspect with regards to extra vibration being induced and the effects of this on fatigue life and account for road temperatures when doing so

Definitely a difference between summer and winter in terms of performance of my car - in colder weather, peak boost was higher and boost came on harder. Occasionally harder to get traction, but difficult to determine whether due to colder tyres, colder roads, higher power output or faster boost response.

Definitely a difference between summer and winter in terms of performance of my car - in colder weather, peak boost was higher and boost came on harder. Occasionally harder to get traction, but difficult to determine whether due to colder tyres, colder roads, higher power output or faster boost response.

Thanks for the reply. Ideal

I hope folk don't mind if I directly quote posts for use in one of my appendices?

I have voted the first option, Yes.

My previous auto TT did indeed seem & feel quicker on colder days (especially early mornings), the traction loss that sometimes occurred I mainly put down to the road surface & rubber not being in optimisded working temperatures hence the easy break in traction. The extra torque most likely would have played a part in this too.

Skip over this if I'm teaching you to suck eggs, but you could have a look at the standard equations for temperature and pressure correction for power. This will allow you to asses what the various standarsd agencies (DIN, ISO, SAE and JIS) consider to be the variation of power with atmospheric conditions, so you can do some simple modelling of what the power (and hence torque) variation through the transmission might be without resorting to complex performance simulation. I did a quick Google and found the equations in this article.

I've voted yes, because I know that cooler air results (in theory) in more available oxygen to burn and also negatively affects the tyres grip on the road. However. the temperature terms in the DIN and SAE equations suggest a correction factor of about +3.6% for a 20 degree drop in temperature, which is a significant amount, but whether or not this is enough to always make you break traction kind of implies that you are almost always within about 4% of the limit of grip which doesn't sound very likely to me. Its also a big temperature drop. I would speculate that 20 degrees off your tyre temperature would have a bigger affect than 3.6% more torque.

For engines today you might need to take into account that a modern torque-based ECU might not care one jot what the ambient conditons are, as it will turn the pedal positon into a torque demand that it should satisfy without "overshooting" the mark, as it were, so you might not have to design in a torque overhead to account for variations in atmospheric conditions.

Thanks for the reply. Ideal

 

I hope folk don't mind if I directly quote posts for use in one of my appendices?

No problems. I should clarify, on re-reading my post, that I'm talking about *relative* traction - my car can break traction on boost in 1st-4th, but seemed easier to wheelspin in colder weather (especially when brake-boosting in 3rd, or going WOT on a roll).

Thank you for the responses so far folks, more welcomed!

(Also, bump to the top ).

194 views on and only 15 contributions to the poll - tragic behaviour Supra owners!

(Late night bump so I can add to my content in the morning ).

I'm TT6 and have noticed on the same piece of road, with the same boost setting on my EBC on warmer days it hits the level expected and colder days I find it hitting peak boost (which is around 0.2 bar higher) and also it feeling like that is achieved far quicker.

Now I am aware that is very basic stuff that we all know but wasn't sure if it would be useful for you to quote later if needed.

If not, sorry for wasting 30 seconds of your life

Final (hopefully) bump on this one folks!

The project is due in on Thursday at 12pm so I'm hoping to have it wrapped up soon! As this part can just be expanded with quotes to reinforce/oppose my suggestion that I am putting forward, more replies would be great!

Cheers

Ok, as I type this reply, I am now on the section where this poll is being integrated.

If you have anything to add to it through your experiences, please do so very soon! I shall refresh the page once I have finished writing the portion relating to this topic and gather the quotes for the appendix then.

As an aside, thanks once again to all that have contributed thus far. I really appreciate it

Forgot to close this off by saying thanks once again to everyone that contributed to this section of my project. A pretty good pass was the outcome and so I successfully graduated and slotted into a nice engineering job that I am typing this message from

Forgot to close this off by saying thanks once again to everyone that contributed to this section of my project. A pretty good pass was the outcome and so I successfully graduated and slotted into a nice engineering job that I am typing this message from

Congratulations. Well...What do you do and where do you work?

I assume everyone who voted is now due a cut?

Congratulations. Well...What do you do and where do you work?

 

I assume everyone who voted is now due a cut?

I work with the design engineering team at EnerMech. Cranes, lifting gear, valves and tool rental/supply. It is a good learning curve for sure!

Unfortunately I can't see the names of all of those that voted so they will be unable to receive anything.

For those that I quoted for the project, they receive my utmost gratitude

Call it £18,000 cash for me

It took me almost 3 minutes to write it man!!

Congratulations