Team-BHP > Technical Stuff


Reply
 
Thread Tools Search this Thread
Old 25th January 2021, 10:36   #61
Senior - BHPian
 
Join Date: Oct 2011
Location: Hyderabad
Posts: 11,953
Thanked: 19,818 Times
Default Re: Turbocharged engines and the idling start / stop system

Quote:
Originally Posted by venkyhere View Post
what if there is a steep ramp to climb out of parking, on a cold morning ? what will be your take on what to do in that case ?
1) start moving from parked position in 10 seconds and then when engine temp is low, climb the ramp & load the engine
OR
2) idle for 1 min, move out of parked position and climb the ramp & load the engine when engine is slightly warmer
I feel Point 1 is what is better to do unless the ramp is ultra steep and will require revving the nuts.

Idling say 15-20 seconds should set all fluids flowing internally (read engine oil) and since the oil galleries will have some residual oil in there already, flow will be faster and will avoid excessive wear. Idling actually will take longer for the engine to reach the operating temperature and it is best to drive off after 10-15 seconds. I might be wrong in my thinking so please correct me if I'm wrong.
a4anurag is online now  
Old 25th January 2021, 10:51   #62
Senior - BHPian
 
balenoed_'s Avatar
 
Join Date: Jul 2016
Location: KL14 <> KA01
Posts: 1,131
Thanked: 2,608 Times
Default Re: Turbocharged engines and the idling start / stop system

Quote:
Originally Posted by Dr.AD View Post
So again, it is not a dumb system that will casually switch off the engine at every single stop. It is a pretty sophisticated system that knows what it is doing.
I second that.

This I double checked with my Scorpio today. On an ideal normal short duration drives, the auto shut off happens in ~3s. While when I did a 50Kms non stop drive and stopped, the auto shut off happened in about ~8s.
balenoed_ is offline   (2) Thanks
Old 25th January 2021, 12:32   #63
Distinguished - BHPian
 
Join Date: Oct 2012
Location: Delhi
Posts: 6,053
Thanked: 25,591 Times
Default Re: Turbocharged engines and the idling start / stop system

Quote:
Originally Posted by venkyhere View Post
what if there is a steep ramp to climb out of parking, on a cold morning ? what will be your take on what to do in that case ?
1) start moving from parked position in 10 seconds and then when engine temp is low, climb the ramp & load the engine
OR
2) idle for 1 min, move out of parked position and climb the ramp & load the engine when engine is slightly warmer
What you need to understand is that on modern engines, especially diesels, a minute of idling hardly does anything for the oil temperature. It won’t make a difference.

So just drive off.

We are talking about cumulative wear over the life span of an engine. So thousands of engine starts. Once doing is not going to make a noticeable difference.

Jeroen
Jeroen is online now   (3) Thanks
Old 25th January 2021, 21:09   #64
BHPian
 
venkyhere's Avatar
 
Join Date: Mar 2011
Location: hump city
Posts: 787
Thanked: 2,226 Times
Default Re: Turbocharged engines and the idling start / stop system

Quote:
Originally Posted by Jeroen View Post
What you need to understand is that on modern engines, especially diesels, a minute of idling hardly does anything for the oil temperature. It won’t make a difference.

So just drive off.

We are talking about cumulative wear over the life span of an engine. So thousands of engine starts. Once doing is not going to make a noticeable difference.

Jeroen
that's the point I was originally making - the presence of a steep ramp right at the start (say, 20 seconds to reach it, if driven off immediately after crank) is the real deal breaker (wear inducing) here that is going to load the engine (even in 1st gear) when oil is not warm enough, whether idling is followed or not, years and years of doing this will inflict wear.

How will you classify two exactly same cars - one parked in a basement like above and one parked on level ground (which doesn't need to climb a ramp) , each of them starting 365 days a year and driving off in the same manner, for 4/5 years or running 100k odo. Will there be a noticeable difference in wear between the two ? If yes, engine design and oil engineering are still not "fully reliable" yet

Last edited by venkyhere : 25th January 2021 at 21:10.
venkyhere is offline  
Old 25th January 2021, 22:15   #65
Distinguished - BHPian
 
Join Date: Oct 2012
Location: Delhi
Posts: 6,053
Thanked: 25,591 Times
Default Re: Turbocharged engines and the idling start / stop system

Quote:
Originally Posted by venkyhere View Post
How will you classify two exactly same cars - one parked in a basement like above and one parked on level ground (which doesn't need to climb a ramp) , each of them starting 365 days a year and driving off in the same manner, for 4/5 years or running 100k odo. Will there be a noticeable difference in wear between the two ? If yes, engine design and oil engineering are still not "fully reliable" yet
Yes, if everything else is identical (the cars are driven in an identical way) there would be a difference in wear. How much is impossible to say. But climbing a ramp, even a steep one, would take a short while only. We are talking about minute cumulative wear. So once a day 10-20 seconds of running a cold engine at a bit of loading is unlikely to be a major problem.

Gut feeling is idling the engine is likely worse than a bit of engine loading anyway.

I am not sure what you mean with engine/oil design and engineering not fully reliable yet. I am not aware of a single design that does not have limitations. Whether it is a car, a plane or a coffeemaker. Take it beyond its normal operating instructions and you are likely to see problems, or additional wear and tear.

You want to push a performance envelop it is just a question of money. How much more expensive can an engine/car be to solve this? In practice it tends to be more of a theoretical problem. Certainly for the first 100-150K kilometers.

So you are wearing the piston rings and the cilinder (liners). To a lesser extend probably bearings/cams/valve stem seals a bit too. How big a problem is that really? The first sign of this kind of wear tends to be oil consumption.

As long as you are not loosing compression you can debate how relevant engine wear, or oil consumption is? We have another thread on oil consumption. Lots of people are very concerned, but on many engines up to 1l of oil consumption per 1000 km is not considered a problem at all. (again, do not believe me, but check your owner manual!).

An engine overhaul is expensive, adding some oil now and then is not.

Jeroen
Jeroen is online now   (2) Thanks
Old 26th January 2021, 21:51   #66
BHPian
 
venkyhere's Avatar
 
Join Date: Mar 2011
Location: hump city
Posts: 787
Thanked: 2,226 Times
Default Re: Turbocharged engines and the idling start / stop system

Quote:
Originally Posted by Jeroen View Post
I am not sure what you mean with engine/oil design and engineering not fully reliable yet. I am not aware of a single design that does not have limitations. Whether it is a car, a plane or a coffeemaker. Take it beyond its normal operating instructions and you are likely to see problems, or additional wear and tear.
The point is to design it to withstand extreme operating points , while enforcing the working zone to conservative operating points. But it's one of those business decisions where reliability will be the justification for incurring extra design&manufacturing cost, without any extra performance to show for it. Like making a crane to lift 100 tonnes, but mention 50 tonnes on its spec sheet.
venkyhere is offline  
Reply

Most Viewed
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Copyright ©2000 - 2021, Team-BHP.com
Proudly powered by E2E Networks