Go Back   Team-BHP > Under the Hood > Technical Stuff


Reply
 
Thread Tools Search this Thread
Old 16th March 2008, 19:56   #1
BHPian
 
sreenivass's Avatar
 
Join Date: Oct 2006
Location: Bangalore India
Posts: 872
Thanked: 6 Times
Default Is this ECU learning affecting my FE ?

Gurus,

I have been driving a Petra for 3+ Yrs and have an interesting observation. For a good part of the 3 years I used to do early shift in city driving like shifting to 3rd at 28 KMPH, 4th around 40 KMPH 5th around 50 KMPH. Most of the time I used to get around 9.5+ to 11.5+ KMPL (more of it around 10 to 10.5 KMPL) in this driving style. Over the last couple of months I started shifting a bit late like: 35 KMPH to 3rd, 45-50 KMPH to 4th and around 60 KMPH to 5th. With this new style what I have observed is until half tank empty I am covering over 250 KMs which is like 11 KMPL. As I continue without refilling I see the final KMPL coming to around 9.5+, I am tightening vigil because of suspected pilferage. Do you think there can be a technical reason for this ?
sreenivass is offline   Reply With Quote
Old 16th March 2008, 20:26   #2
Team-BHP Support
 
Eddy's Avatar
 
Join Date: Apr 2007
Location: Delhi
Posts: 7,402
Thanked: 4,680 Times
Default

I think that the top half of the fuel meter is calibrated differently from the second half. In other words, from "F" to halfway the needle moves slowly compared from halfway to "E".
Eddy is offline   Reply With Quote
Old 16th March 2008, 23:03   #3
Senior - BHPian
 
Join Date: Jun 2007
Location: Kochi
Posts: 2,147
Thanked: 143 Times
Default

Unlike the speedo- and odo- meters, the fuel indicator is just that - an indicator. It is NOT a meter. Never count mileage by position of the needle. If you want to check FE, use the topup-to-topup fuel consumption divided by distance as per the trip meter.
BaCkSeAtDrIVeR is offline   Reply With Quote
Old 16th March 2008, 23:46   #4
BHPian
 
Sagittarian's Avatar
 
Join Date: Aug 2007
Location: Chennai
Posts: 61
Thanked: Once
Default

Quote:
I think that the top half of the fuel meter is calibrated differently from the second half. In other words, from "F" to halfway the needle moves slowly compared from halfway to "E".
Eddy is correct. In Aveo also, I have noticed that the movement of the needle is not in linear correspondence with the petrol level. Beyond H(alf), it moves down slowly, then after some descend, it starts sinking real fast.
Sagittarian is offline   Reply With Quote
Old 17th March 2008, 00:14   #5
Team-BHP Support
 
Rehaan's Avatar
 
Join Date: Feb 2004
Location: Bombay
Posts: 22,381
Thanked: 22,606 Times
Default

Eddy and Backseatdriver have got it right on this one i think.

Quote:
Originally Posted by BaCkSeAtDrIVeR View Post
If you want to check FE, use the topup-to-topup fuel consumption ....
http://www.team-bhp.com/forum/indian...-your-car.html (How do you calculate mileage for your car)

cya
R
Rehaan is offline   Reply With Quote
Old 18th March 2008, 04:42   #6
BHPian
 
sreenivass's Avatar
 
Join Date: Oct 2006
Location: Bangalore India
Posts: 872
Thanked: 6 Times
Default

I agree with Fuel indicator part, why was it different earlier. I used to cover only around 200-220 KM earlier for half way mark in indicator.
sreenivass is offline   Reply With Quote
Old 18th March 2008, 08:32   #7
BHPian
 
S@~+#0$#'s Avatar
 
Join Date: Mar 2006
Location: Bangalore
Posts: 700
Thanked: 37 Times
Default

Since you are aware of the above suggestions, I recommend you reset the ECM. Follow the steps below:
1) Go to an empty stretch
2) Disconnect the -ve terminal of your battery.
3) Wait for 5 minutes and connect the terminal again.
4) Then drive the car in your new style of driving ie., late shifts.

The ECM learns and gets adapted to your new style of driving and then stores the best values for this kind of driving. Try it, I am confident it will work.
S@~+#0$# is offline   Reply With Quote
Old 18th March 2008, 08:36   #8
Senior - BHPian
 
gemithomas's Avatar
 
Join Date: Jan 2007
Location: Trivandrum
Posts: 2,364
Thanked: 136 Times
Default

Quote:
Originally Posted by sreenivass View Post
Gurus,

I have been driving a Petra for 3+ Yrs and have an interesting observation. For a good part of the 3 years I used to do early shift in city driving like shifting to 3rd at 28 KMPH, 4th around 40 KMPH 5th around 50 KMPH. Most of the time I used to get around 9.5+ to 11.5+ KMPL (more of it around 10 to 10.5 KMPL) in this driving style. Over the last couple of months I started shifting a bit late like: 35 KMPH to 3rd, 45-50 KMPH to 4th and around 60 KMPH to 5th. With this new style what I have observed is until half tank empty I am covering over 250 KMs which is like 11 KMPL. As I continue without refilling I see the final KMPL coming to around 9.5+, I am tightening vigil because of suspected pilferage. Do you think there can be a technical reason for this ?
Its simple. You are running at higher rpm's. Thus the mileage figures are getting a hit while you are being given enough and more power. Earlier you used to shift before the 2K rpm mark and now you are shifting way above that mark. Thats the difference between 10.5 km/l and 9.5km/l i guess.

The fuel gauge needle is just an indicator. But not sure wh it behaves differently now.
gemithomas is offline   Reply With Quote
Old 18th March 2008, 10:59   #9
BHPian
 
Su-47's Avatar
 
Join Date: Aug 2006
Location: Bangalore
Posts: 624
Thanked: 91 Times
Default

Are we serious about the ECM "learning" something from the driver's driving style? I had no clue that something like this is happening under the hood, until I read it here.

So, if I and a friend have the same car and his *normal* driving is more aggressive than me and we decide to race one day, would the ECMs of our cars respond differently. Would my car's ECM respond with "You've usually been a good boy, what has happened to you? Let me respond with my usual laziness, so that you don't win this race and stay away from such misadventures."
Su-47 is offline   Reply With Quote
Old 18th March 2008, 11:28   #10
Team-BHP Support
 
Zappo's Avatar
 
Join Date: Oct 2005
Location: Hyderabad
Posts: 5,653
Thanked: 2,013 Times
Default

Quote:
Originally Posted by Su-47 View Post
Are we serious about the ECM "learning" something from the driver's driving style? I had no clue that something like this is happening under the hood, until I read it here.

So, if I and a friend have the same car and his *normal* driving is more aggressive than me and we decide to race one day, would the ECMs of our cars respond differently. Would my car's ECM respond with "You've usually been a good boy, what has happened to you? Let me respond with my usual laziness, so that you don't win this race and stay away from such misadventures."
haa haaa haaaa... Su, that was hilariously put through.

Well, coming back to reality there are indeed such technologies available where the car's ECU module is a self-learning one. Honda and other car majors do have such technologies available. I do not know if the Indian cars though have such a feature. At least not the mass cars I suppose. I am not sure of this but I think the Laura has something like.

Coming to what you said, the car won't punish you for driving aggressively but it will return poor fuel efficiency than what your friend's car will for the same kind of driving.
Zappo is offline   Reply With Quote
Old 19th March 2008, 01:02   #11
BHPian
 
chetanhanda's Avatar
 
Join Date: Mar 2005
Location: Toronto
Posts: 886
Thanked: 42 Times
Default

Quote:
Originally Posted by sreenivass View Post
Gurus,
I have been driving a Petra for 3+ Yrs and have an interesting observation. For a good part of the 3 years I used to do early shift in city driving like shifting to 3rd at 28 KMPH, 4th around 40 KMPH 5th around 50 KMPH. Most of the time I used to get around 9.5+ to 11.5+ KMPL (more of it around 10 to 10.5 KMPL) in this driving style. Over the last couple of months I started shifting a bit late like: 35 KMPH to 3rd, 45-50 KMPH to 4th and around 60 KMPH to 5th. With this new style what I have observed is until half tank empty I am covering over 250 KMs which is like 11 KMPL. As I continue without refilling I see the final KMPL coming to around 9.5+, I am tightening vigil because of suspected pilferage. Do you think there can be a technical reason for this ?
There is a technical reason - you are driving it more aggresively as compared to earlier.
Even if you had a carburettor instead of an ECU you will notice the same thing.
You are revving the car higher and shifting late so you will consume more fuel.
What's the mystery dude ? ECU is just doing its job - you asked for more fuel by revving higher, the ECU didnt do that on its own.
You basically answered you own question when you said you are shifting late.

Quote:
Originally Posted by Zappo View Post
haa haaa haaaa... Su, that was hilariously put through.

Well, coming back to reality there are indeed such technologies available where the car's ECU module is a self-learning one. Honda and other car majors do have such technologies available. I do not know if the Indian cars though have such a feature. At least not the mass cars I suppose. I am not sure of this but I think the Laura has something like.

Coming to what you said, the car won't punish you for driving aggressively but it will return poor fuel efficiency than what your friend's car will for the same kind of driving.
All ECU's have that, every ECU keeps updating values based on the engine's health and how you drive it.

Last edited by chetanhanda : 19th March 2008 at 01:15.
chetanhanda is offline   Reply With Quote
Old 19th March 2008, 01:10   #12
Senior - BHPian
 
v1p3r's Avatar
 
Join Date: Feb 2005
Location: BLR - chasing cars...
Posts: 4,836
Thanked: 26 Times
Default

Quote:
Originally Posted by Su-47 View Post
So, if I and a friend have the same car and his *normal* driving is more aggressive than me and we decide to race one day, would the ECMs of our cars respond differently. Would my car's ECM respond with "You've usually been a good boy, what has happened to you? Let me respond with my usual laziness, so that you don't win this race and stay away from such misadventures."
Yes, that's exactly what will happen. Been there, done that.
v1p3r is offline   Reply With Quote
Old 19th March 2008, 07:58   #13
Team-BHP Support
 
moralfibre's Avatar
 
Join Date: Dec 2004
Location: MH-12
Posts: 6,625
Thanked: 6,149 Times
Default

Quote:
Originally Posted by Su-47 View Post
So, if I and a friend have the same car and his *normal* driving is more aggressive than me and we decide to race one day, would the ECMs of our cars respond differently. Would my car's ECM respond with "You've usually been a good boy, what has happened to you? Let me respond with my usual laziness, so that you don't win this race and stay away from such misadventures."
Quote:
Originally Posted by v1p3r View Post
Yes, that's exactly what will happen. Been there, done that.

And v1p3r is right here. There is something called "Self adapting parameters" on your ECU that collects data depending on your driving style. That is the reason why you have "Zeroing of self adapting parameters" option on the examiner (at least in Fiat there is). Once reset you are supposed to start the car and leave it on idle for a while to collect data after which you drive around for a while and the ECU collects information based on your driving style. I don't have technical details on this one.
moralfibre is offline   Reply With Quote
Old 22nd March 2008, 23:03   #14
BHPian
 
sreenivass's Avatar
 
Join Date: Oct 2006
Location: Bangalore India
Posts: 872
Thanked: 6 Times
Default mystery is the fuel indicator

Quote:
Originally Posted by chetanhanda View Post
There is a technical reason - you are driving it more aggresively as compared to earlier.
Even if you had a carburettor instead of an ECU you will notice the same thing.
You are revving the car higher and shifting late so you will consume more fuel.
What's the mystery dude ? ECU is just doing its job - you asked for more fuel by revving higher, the ECU didnt do that on its own.
You basically answered you own question when you said you are shifting late.


All ECU's have that, every ECU keeps updating values based on the engine's health and how you drive it.
Well the question is more on why the indicator behaves this way. Higher revs and lesser FE is obvious, but the average FE is not a whole lot different. Why does it show as if there is higher FE for the first half tank, can it change with weather ?
sreenivass is offline   Reply With Quote
Old 27th March 2008, 20:52   #15
BHPian
 
chetanhanda's Avatar
 
Join Date: Mar 2005
Location: Toronto
Posts: 886
Thanked: 42 Times
Default

Quote:
Originally Posted by sreenivass View Post
Well the question is more on why the indicator behaves this way. Higher revs and lesser FE is obvious, but the average FE is not a whole lot different. Why does it show as if there is higher FE for the first half tank, can it change with weather ?
The title of the thread says "Is this ECU learning my FE ?" ..thats why.

Anyways..theres something wrong with the fuel indicator.
Same with my car, it comes down quickly to the 1/2 way mark and goes down to empty pretty slowly in summer/winter ,maybe its not calibrated very accurately.

Last edited by chetanhanda : 27th March 2008 at 20:55.
chetanhanda is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Factors Affecting Reliability dhanushs Technical Stuff 66 2nd July 2014 11:59
What is the most important factor affecting speed? Power, Torque, or Gearbox? holysmoke Technical Stuff 27 5th April 2010 18:14
swift audio setup without affecting boot space ronk In-Car Entertainment 22 15th October 2007 10:47
Factors affecting Thermal eff vs FE and diesel vs petrol etc jat Technical Stuff 3 21st February 2006 23:09


All times are GMT +5.5. The time now is 02:32.

Copyright 2000 - 2017, Team-BHP.com
Proudly powered by E2E Networks