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


Closed Thread
 
Thread Tools Search this Thread
Old 27th August 2007, 19:38   #16
BHPian
 
Join Date: Jul 2006
Location: pune
Posts: 241
Thanked: Once
Default lean burn!!

Quote:
Originally Posted by mclaren1885 View Post
Basically you mean to say RUN LEAN? Isn't that harmful to the engine?
yes and no!
leaning out beyond the design parameters will be dangerous and that will happen if there is no lambda sensor or non functional one . modern engines are designed to oprate at 14.7-14.5 <ratio varies depending the composiation of fuel in the country > and lambda plus minus 5 percent AT OPRATING TEMPERATURE. that is @ 85 to 95 deg c depends upon the designer ,
unless and untill the engine doesnot reach the std oprating temp it is kept rich and then approches as the temp rises<thats the reason the cars have higher initial rpm when u cold start it ..if the engine is made to run on wormer air/hotter air then the ecu will lean out the fuelling much earlier .
TURBOSAM is offline  
Old 27th August 2007, 19:48   #17
Team-BHP Support
 
moralfibre's Avatar
 
Join Date: Dec 2004
Location: MH-12
Posts: 6,625
Thanked: 6,150 Times
Default

Nice thread Sameer. We did a mileage marathon between the Honda Activa, the Kinetic Nova, Bajaj Sapphire and TVS Scooty Pep for some magazine. We had Dilip Bam along and we managed to extract unbelievable figures just because we wanted to. Now that we got 68 kmpl from one of the scooters Dilip wrote what ideal conditions of testing are:

Quote:
I took it out of town on an un-trafficked road and did a test under “IDEAL” conditions, which was at steady 50 KPH, with no jackrabbit starts, no overtakings, no hi-speeding and almost no braking. Over a run of 3.4 km, I got an astounding 68 kms per litre!
moralfibre is offline  
Old 27th August 2007, 19:55   #18
BHPian
 
Join Date: Jul 2006
Location: pune
Posts: 241
Thanked: Once
Default octane rating of fuel!

one more point i missed.. to get max fuel efficiency u need to use LOWEST POSSIBLE octane rated fuel WHICH WILL NOT INDUCE KNOCK in the perticular engine .<and it varies from engine to engine . dohc 4 valves/cylinder with semi hemi combustion chembers with good amount of squish band can have the widest octane oprating range>
its exactly opposite in the max power quest .
so technically u should get equal or lesser fe when using high octane rated fuel than the normal one .
TURBOSAM is offline  
Old 27th August 2007, 19:58   #19
BHPian
 
Vayalam's Avatar
 
Join Date: Jun 2007
Location: Chennai
Posts: 26
Thanked: 0 Times
Default

If intake air should ideally hotter, where does an intercooler fit in? Pardon me if I'm being stupid.
Vayalam is offline  
Old 27th August 2007, 20:02   #20
BHPian
 
Join Date: Jul 2006
Location: pune
Posts: 241
Thanked: Once
Default its the efficiency of the engine cycle - not the cost of fuel

Quote:
Originally Posted by narayan View Post
not at all for my car - but just want to know

1) what it costs ?
2) whether buying a diesel or plonking a LPG/CNG cyinder or going electric is cheaper
- hi evev in diedels we will have better efficiency plus much reduced diesel knock when the engine is cold simple -- up to a certain temp hotter the engine lesser the heat losses<in ic engines @25 to 35 %>
fitting lpg/cng will reduce the oprational cost AM TALKING ABOUT EFFICIENCY thermal efficiency
TURBOSAM is offline  
Old 27th August 2007, 21:24   #21
BANNED
 
mclaren1885's Avatar
 
Join Date: Jul 2005
Location: Bangalore (the city of modded cars) !!
Posts: 4,821
Thanked: 28 Times
Infractions: 0/1 (10)
Default

IIRC that is exactly the reason we have EGR on most of the newer cars. What the EGR (Exhaust Gas Recirculation) does is as its name suggests it recirculates the exhaust gases back into the intake? Thus the slightly warmer intake temperatures will further cause lean burn improving FE. That is one of the reasons why the baleno went from 94 to 91 bhp.

Regarding, higher octane fuel if I am not wrong lower octane will induce additional torque? Because what I have noticed is that by using higher octane fuel the engine normally tends to rev more freely and doesn't feel as torquey as say when you use lower octane fuel.
mclaren1885 is offline  
Old 27th August 2007, 22:23   #22
BHPian
 
Join Date: Jul 2006
Location: pune
Posts: 241
Thanked: Once
Default egr and the efficiency

Quote:
Originally Posted by mclaren1885 View Post
IIRC that is exactly the reason we have EGR on most of the newer cars. What the EGR (Exhaust Gas Recirculation) does is as its name suggests it recirculates the exhaust gases back into the intake? Thus the slightly warmer intake temperatures will further cause lean burn improving FE. That is one of the reasons why the baleno went from 94 to 91 bhp.

Regarding, higher octane fuel if I am not wrong lower octane will induce additional torque? Because what I have noticed is that by using higher octane fuel the engine normally tends to rev more freely and doesn't feel as torquey as say when you use lower octane fuel.
egr is introduced to control the emissions coming out of the car if not the engine.when exhaust is introduced in the fresh air or air fuel mixture there are less marriages between oxygen in air and fuel molecules.so less heat is produced- so less temp is reached so less marriages of oxygen and nitrogen and less nitrous oxide<no2> is produced which is bad for the lungs!
egr actually reduces the engine 's thermal efficiency!
IF BEST OF THE designers are allowed to add inherently better designs to begin with .then they add quick opening valve profiles with less duration plus
there is lesser overlap and late valve openings .. less mixing of flue gases with fresh charges +less fresh air fuel escapes out of exhaust valves increasing the emissions plus misleading labbda reading then u may not need egr at all at least till euro 3 emission norms! <palio 1.6 is such a design marvel doesnot have an egr valve and it passes euro 4 norns from 2001!! thats technology!!
and in the case of other engines, egr opens at certain conditions those are - rpm highre than x, ac-off, pedal not fully or 3/4 depressed<in short rpm is high but the power demanded is not high and engine is running at part throttle &part load.>
when u demand power. egr is switched offf,
at any cost e.g.r cannot increase the power output by itself.. its an absolute necesity for some engines not an asset.
egr valves are added to the engines which will not pass the emission norms otherwise!!
and in most of the cases the power drops!!

Last edited by TURBOSAM : 27th August 2007 at 22:37. Reason: ADDED INFO
TURBOSAM is offline  
Old 29th August 2007, 12:52   #23
BHPian
 
Join Date: Nov 2006
Location: kolkata
Posts: 927
Thanked: 24 Times
Default

Turbosam, I drive a 99 carb zen, was getting a mileage of 7-7.5 with ac 90% on, did engine tuning at a maruti authorised outlet, mileage went up to 8-9 kmpl, and the max I got was 10.3 when I went for some long drives. Any ideas on what more I can do, I'm not a harsh driver and drive normally, don't rev too much in each gear, even then nogo. If you could achieve such high figures on a 1.6 palio, then my zen should atleast give me 14-15 with 90% ac. Please sugguest some ideas, as I have been trying to increase my mileage for ages now, just chaged the air-filer also about 400 kms back.
musicmanaman is offline  
Old 30th August 2007, 17:33   #24
BHPian
 
Join Date: Jul 2006
Location: pune
Posts: 241
Thanked: Once
Default get 20+kmpl from zen .. but first, get these things checked!

Quote:
Originally Posted by musicmanaman View Post
Turbosam, I drive a 99 carb zen, was getting a mileage of 7-7.5 with ac 90% on, did engine tuning at a maruti authorised outlet, mileage went up to 8-9 kmpl, and the max I got was 10.3 when I went for some long drives. Any ideas on what more I can do, I'm not a harsh driver and drive normally, don't rev too much in each gear, even then nogo. If you could achieve such high figures on a 1.6 palio, then my zen should atleast give me 14-15 with 90% ac. Please sugguest some ideas, as I have been trying to increase my mileage for ages now, just chaged the air-filer also about 400 kms back.
hi
to begin with u have a good car with one of the best engines around .
the mileage u claim is less than u should be getting .that is
@12 in city and @15 16 in a/c on highway ..
assuming u have a manual gear box and all the systems are in good conditions.
1><if its not already scrapped by the old mechanic> and if required renew the THERMOSTAT-- cooler engine saps lot of energy. more friction as engine never comes to the designed opration temp .
2 > fuel return line is not clogged
3>get the carburettor cleened/ overhauled by an expert .
there is an arrangement called as accelerator pump - the function of it is --to avoid a flat spot its designed to squirt a jet some fuel everytime u touch the accelerator. its suppose to hold the petol in hold position till its orderded to squirt . if the diphram <power valve diphram kit-in maruti terminalogy>is leaking or the one way valve is clogged , ull end up wasting extra fuel .
4> after the diphram , get the accelerator pump stroke set properly to squirt just the required amount of fuel not more, not too less,
5.> check the correct heat range of sparkplugs -- as per the manual ,and set the gaps ase per the manual
6> check the ignition system for leakages.. generally old systems<cords,coils, terminals,delco caps > loose spark energy at max torque rpm when in cylinder compression is too dense to jump the spark of sufficient intencsty for sufficient time .
7>check and reset the ignition timing static as well as dynamic get the advance mechanism checked .
8>GET THE VALVE TIMING CHECKED.<if required replace the timing belt too > if the cam is retarded it will loose low to midrange power < in the contrey ,advancing the cam by 4 to 7 degrees from the standard will make noticible difference in low end torque mid range power till @ 4000rpm !! pay off.. it will taper the power at high rpm more sharply but as u dont drive it that high for the 99.99.99 %of ur driving cycle u cal always try it .
8>check and adjust the valve clearance .
9>get the exhaust system cleened by washing with liquid soap and semi pressurised water .clraner the exhaust.. lesser the back pressuree.. lesser the power wasted in pushing the exhaust gases out at the exhaust stroke .
10>get the radiator and condenser washed externally with running tap water when engine is running and car is in a/c < the running fan sucks away the water away along with the dirt and grime . then keep the engine running in a/c till the radiator and condenser are dried completely <so they wont accumulate dirt again immediately on wet surfaces!!>.
cleaner radiator means better heat transfer . that means lesser time the fan runs .. lesser electrical load ... lesser alternator load .. lesser engine load ..lesser fuel .
cleaner condenser has similer but more pronunced benifits,

and u should be getting @17 19 on highway in ac with good driving technique it can be stretched to 20 22 .
all the best
keep me posted .

Last edited by TURBOSAM : 30th August 2007 at 17:42.
TURBOSAM is offline  
Old 30th August 2007, 17:40   #25
Team-BHP Support
 
mobike008's Avatar
 
Join Date: Sep 2006
Location: Hyderabad
Posts: 10,749
Thanked: 7,967 Times
Default

Whew, turbosam, are you doing your automobile engineering and trying to impress the hell out of all folks out here??

Just kidding
mobike008 is offline  
Old 30th August 2007, 18:06   #26
Team-BHP Support
 
moralfibre's Avatar
 
Join Date: Dec 2004
Location: MH-12
Posts: 6,625
Thanked: 6,150 Times
Default

Quote:
Originally Posted by mobike008 View Post
Whew, turbosam, are you doing your automobile engineering and trying to impress the hell out of all folks out here??
He is already one . I know.
moralfibre is offline  
Old 30th August 2007, 18:47   #27
BHPian
 
Join Date: Feb 2007
Location: Madras
Posts: 558
Thanked: 2 Times
Default

Wow TurboSam! That was an impressive write-up. Great mind you have. Hats off to you for giving all those excellent points.

cya
A

Last edited by Absar : 30th August 2007 at 18:48.
Absar is offline  
Old 30th August 2007, 19:01   #28
BHPian
 
Join Date: Nov 2006
Location: kolkata
Posts: 927
Thanked: 24 Times
Default

Hi Turbosam,

Thanks for that extensive write up, it's a little technical for me, but I guess these are the things I should tell the Maruti Authorised service center to do.

1. Clean and Service the Carb.
2. Change the Spark Plugs.
3. Check Timing Belt.
4. Wash the front of the Car throughly with Water Spray when Engine and
A/C is on.
5. Tune the engine.

Is there anything I'm missing, din't understand the Thermostat and the fuel return line part much.

I'm also changeing the engine oil in the next 2 days, does this help?

Thanks Again.
musicmanaman is offline  
Old 30th August 2007, 22:19   #29
BHPian
 
Join Date: Jul 2006
Location: pune
Posts: 241
Thanked: Once
Default not again!!

Quote:
Originally Posted by mobike008 View Post
Whew, turbosam, are you doing your automobile engineering and trying to impress the hell out of all folks out here??

Just kidding
did it in the past...@10 yrs back.
and last 10 yrs ,trying to figureout what i missed in my sylibus
TURBOSAM is offline  
Old 30th August 2007, 22:37   #30
BHPian
 
Join Date: Jul 2006
Location: pune
Posts: 241
Thanked: Once
Default hello!

Quote:
Originally Posted by musicmanaman View Post
Hi Turbosam,

Thanks for that extensive write up, it's a little technical for me, but I guess these are the things I should tell the Maruti Authorised service center to do.

1. Clean and Service the Carb.
2. Change the Spark Plugs.
3. Check Timing Belt.
4. Wash the front of the Car throughly with Water Spray when Engine and
A/C is on.
5. Tune the engine.

Is there anything I'm missing, din't understand the Thermostat and the fuel return line part much.

I'm also changeing the engine oil in the next 2 days, does this help?

Thanks Again.
if u can copy my reply, hand it over to him and make sure the advisor reads,understands it,then hands over the car to the best technician!
as un fortunately nobody pays attention to why part of engg.,they will just lean out the mixture screw by 1-1/2 turns out than std<generally 2.5 turns out from full finger tight>and hand over the car to u .
ull end up paying for alll..as its written on jobcard ..<thanks to computer ,he will bill u automatically>and gain nothing other than a washed car.
please make sure brakes are not binding,car is not pulling in one direction ,tyres and pressure is spot on,and DONT MISS ANYTHING I RECOMANDED,
its very important to order exactly what one wants<rather demands> when the menu card is redy and ur ordering something which is not included!!
all the best.
TURBOSAM is offline  
Closed Thread


Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Autocar India & Ford Fiesta achieve 33 kpl? windsurfer The Indian Car Scene 58 22nd August 2011 20:44
Tata Indica e-xeta petrol with 17.1 kmpl and e-xeta LPG sidindica The Indian Car Scene 7 9th July 2011 12:39
Unable to achieve engine braking robinson.s 4x4 Technical 192 11th July 2010 16:33
How to achieve Max FE in an Opel Corsa? raj_7703 Technical Stuff 22 2nd July 2010 01:17
How to achieve better engine sound? raj_7703 Modifications & Accessories 7 6th November 2009 19:10


All times are GMT +5.5. The time now is 03:16.

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