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


Reply
 
Thread Tools Search this Thread
Old 16th September 2011, 12:03   #226
BHPian
 
Tempelhof's Avatar
 
Join Date: Oct 2007
Location: Bangalore
Posts: 450
Thanked: 123 Times
Default Re: Driver ignorant of how ABS works; Turns Chevy Captiva upside down

Quote:
Originally Posted by VeluM View Post
It is agreed, however that there are two different ways of reacting in an emergency. Both have been outlined, and everyone is free to choose whichever suits them best. To each his own.
I have never been in "great emergency" - thank God - but my instinct is always to (1) press the clutch, (2) disengage the gear, and (3) apply the brakes.

For me all of these three happens instantaneously and simultaneously.

That's the way I ahve practiced so far. (Civic)
Tempelhof is offline   (1) Thanks Reply With Quote
Old 16th September 2011, 12:06   #227
Senior - BHPian
 
VeluM's Avatar
 
Join Date: Jul 2008
Location: Bangalore
Posts: 1,296
Thanked: 663 Times
Default Re: Driver ignorant of how ABS works; Turns Chevy Captiva upside down

Quote:
Originally Posted by suhaas307 View Post
To call my argument opinionated and 'pointless', is rather juvenile.
Sigh. Since you bring it up, here's what I think is a juvenile argument:

- Bringing reaction times into a discussion about emergency driving, with sweeping statements of who should and should not drive on the highway

Simply put, I drive on the highway, and so does my father. He loves to drive, but he is closing in on 70. Are his reflexes any worse for his age? Yes. Will he continue to drive (because he loves to)? Yes.

My father drives safer at 120 than most other drivers at 80 because of his experience and committed anticipatory driving. He mostly doesn't get into a situation where he has to brake in an emergency, because he anticipates and prepares for the worst from every other driver on the road - whithin the realms of reality and probability. Even today, after over 15 years of highway driving behind me, I cannot drive as fast with confidence on the highway - and especially not in the twisties (ghat sections).

My father's reflexes are poorer than mine today, even though he used to be a boxer and NDA academy blue in the boxing team and later captain of the team.

Your argument would virtually exclude most seniors and differently abled people from driving. I am of course not talking about those excluded by law.

I don't really want to drag this on any longer, I don't really like an argument in the midst of a healthy discussion, so let's just drop it.
VeluM is offline   (5) Thanks Reply With Quote
Old 16th September 2011, 12:07   #228
Senior - BHPian
 
mayankk's Avatar
 
Join Date: Apr 2010
Location: New Delhi
Posts: 4,115
Thanked: 3,489 Times
Default Re: Driver ignorant of how ABS works; Turns Chevy Captiva upside down

Quote:
Originally Posted by Tempelhof View Post
I have never been in "great emergency" - thank God - but my instinct is always to (1) press the clutch, (2) disengage the gear, and (3) apply the brakes.

For me all of these three happens instantaneously and simultaneously.

That's the way I ahve practiced so far. (Civic)
and good for you!
there is nothing wrong with doing this.
whatever you take away from this thread, when it comes to the moment of emergency, this IS what you will do.
Its just instinct.
mayankk is online now   Reply With Quote
Old 16th September 2011, 12:13   #229
BHPian
 
Join Date: Feb 2011
Location: Chennai
Posts: 185
Thanked: 46 Times
Default Re: Driver ignorant of how ABS works; Turns Chevy Captiva upside down

Quote:
Originally Posted by Samurai View Post
Oh god, please don't spread such wrong ideas. While panic/emergency braking, you do not touch the clutch or change gears.

For emergency braking with ABS:
1) Jam the brakes fully and focus on the steering to avoid any collisions. ABS lets you steer with brakes fully pressed, that is its main purpose. Just ignore the clutch, you don't have the time to mess around with gears. Also ignore the violent kickback from the brakes, that means ABS is working.
....
I beg to differ Samurai and others who are promoting the idea of pressing only brake in emergency braking.

Emergency braking is stopping your car in minimum distance without stalling your engine. so, it make sense and is right way to do the "Emergency braking" that you press clutch and brake simulatenously. we can always change gear when you are ready to go again. true for car with ABS. without ABS, pumping brakes will be the call of hour(or seconds indeed). without ABS your car will be commanding more attention shorter reaction time.

in non-emergency situations, there are several braking techniques. most of us know these by our day-to-day experiences.

Engine braking is irrelevant here, it has meaning only in "slowing down" from higher speeds. like suhass mentioned on crossings and traffic lights where you are in full control of situation.

and yes, as someone mentioned engine braking is more effective in petrol engines than diesel. why? becasue diesel engine produce lot of torque at low rpm and can speed up our car in lower gear rather than slowing it down. even in petrol engines, it is effective when you change from 4-5th to 2-3rd gear respectively. if you change from 3rd to 2nd it tends to speed up!!(well this all depend also on your car. each car has different gear ratio. so, try it with your car before coming to any conclusion.).

Last edited by Suess : 16th September 2011 at 12:26.
Suess is offline   Reply With Quote
Old 16th September 2011, 12:21   #230
Team-BHP Support
 
Samurai's Avatar
 
Join Date: Jan 2005
Location: B'lore-Manipal
Posts: 22,381
Thanked: 14,301 Times
Default Re: Driver ignorant of how ABS works; Turns Chevy Captiva upside down

Quote:
Originally Posted by VeluM View Post
1. Most cars these days have an ECU which picks up on the impending stall on its own and ups the rpm by increasing fuel input.
There are ECUs that send more fuel to the engine when brake is jammed and accelerator pedal is left untouched?

Quote:
Originally Posted by VeluM View Post
PS. My idea is not wrong, it is just my (different) opinion. If you disagree, please say so instead of accusing me of "spreading" wrong ideas.
Hmm, this is not a question of philosophy. But what is the right thing to do.

Quote:
Originally Posted by anilisanil View Post
I am talking this from experience, if for whatever reasons you stall the engine, forget ABS even your brakes do not work and Power steering goes dead and if you are an atheist, those few secs would leave you wondering what to do!!
Quote:
Originally Posted by anilisanil View Post
And lose the control over power steering and lose all the braking, good!
I am not suggesting stalling, that is why I suggested switching to neutral as the car is about to stop.

Quote:
Originally Posted by suhaas307 View Post
Braking suddenly from 120 km/h does not require one to press the clutch. You press the clutch only when the car falls out of its power-band completely, and when the car is almost stationary or crawling, at which point you either switch to neutral or 1st gear, or 2nd, depending on the speed you're doing, once you've braked.

This is how it is done.

The clutch is never depressed, while braking. The basic function of the clutch is to facilitate smooth changing of gears. When you brake suddenly, you are not changing gears, you're coming to a halt, or a slow crawl.

Some argue that it is necessary to press the clutch, because it is easier to do so, considering that the speed is shed so quickly and the correct gear must be chosen after. Some argue that it will stall, if you don't press the clutch, but that's untrue. if you are not quick to react, you are bound to stall.

So if you are not quick to react, pressing the clutch is the easy way out. But it isn't the correct way. If you can't react quick enough, then I'm sorry but, one is not fit to drive on the highway in the first place. Just because it is a simpler technique doesn't make it the correct technique. It's just the simpler way out.
Exactly.

The real blame should go to all the driving schools of India, whose drivers teach every bad habit. My driving instructor in 1992 taught me half-clutching as the primary car driving skill. As a result I burnt out the clutch of my brand new 800 in just 6000 kms. Only then I tried to understand why it is wrong. There are many such bad habits we have, one should try to correct it as our experience/learning increases.
Samurai is offline   (1) Thanks Reply With Quote
Old 16th September 2011, 12:25   #231
Senior - BHPian
 
amitoj's Avatar
 
Join Date: Nov 2004
Location: Nashua, NH
Posts: 2,954
Thanked: 1,591 Times
Default Re: Driver ignorant of how ABS works; Turns Chevy Captiva upside down

I am trying to recall what i have done under emergency braking.
I *think* what i have done is stood on the brakes first and foremost, then as speed has slowed down, pressed clutch to avoid stalling. I dont think i change gears though because both my hands are clutching the steering wheel!!
There is no right way or wrong way. Everyone will do what their instinct tells them to do.
For example, way back in school, girls who were new to riding bicycles, would just abandon the cycle and jump out at a mere honk from behind and we would fall off our cycles from laughing
amitoj is offline   (3) Thanks Reply With Quote
Old 16th September 2011, 12:29   #232
Senior - BHPian
 
VeluM's Avatar
 
Join Date: Jul 2008
Location: Bangalore
Posts: 1,296
Thanked: 663 Times
Default Re: Driver ignorant of how ABS works; Turns Chevy Captiva upside down

Quote:
Originally Posted by Samurai View Post
There are ECUs that send more fuel to the engine when brake is jammed and accelerator pedal is left untouched?
That really a question? Sarcasm aside, the answer is Yes. Try it. Put your car in second while rolling, and release the accelerator and then brake gently (don't really want to stall). The ECU pics up on an impending stall & increases the fuel injected. If you release the brakes at that point, the vehicle will surge ahead before settling down to just above idle rpm - though that takes time.

Quote:
Originally Posted by Samurai View Post
Hmm, this is not a question of philosophy. But what is the right thing to do.
As I said, your way isn't the right way in this particular instance. It is just a way, as is mine.

PS. This discussion is getting way OT, therefore I'm checking out.
VeluM is offline   Reply With Quote
Old 16th September 2011, 12:37   #233
Senior - BHPian
 
humyum's Avatar
 
Join Date: Feb 2006
Location: Leicester/Mumbai
Posts: 2,306
Thanked: 2,188 Times
Default Re: Driver ignorant of how ABS works; Turns Chevy Captiva upside down

I ll give my take on this from an owner of a non ABS Swift Diesel.

I have had numerous high speed emergency braking situations.

In a Panic braking situation if your clutch is not depressed and you brake hard in a non abs vehicle and lock the brakes, your engine is stalled. PERIOD! Even if that means your tyres have locked themselves up at 120 kmph. You can forget about steering the vehicle then unless you let the clutch go again and the engine restarts because of momentum. But i am 100% sure if you have stalled the engine at 120 then your brain wont work in an emergency situation to release the clutch again to restart the engine or for that matter you wont have the time to do the same. Steering control gone.

If its a progressive high speed emergency braking situation, I have always kept my foot on the clutch and pressed it down when i am done with the emergency braking upto 50% of the way so as to not stall the engine.

I believe a clutch is as important as the emergency move so as to not stall the engine and take even the steering away from the vehicle.
humyum is offline   (1) Thanks Reply With Quote
Old 16th September 2011, 12:41   #234
BHPian
 
Join Date: Feb 2011
Location: Chennai
Posts: 185
Thanked: 46 Times
Default Re: Driver ignorant of how ABS works; Turns Chevy Captiva upside down

Quote:
Originally Posted by suhaas307 View Post
Braking suddenly from 120 km/h does not require one to press the clutch. You press the clutch only when the car falls out of its power-band completely, and when the car is almost stationary or crawling, at which point you either switch to neutral or 1st gear, or 2nd, depending on the speed you're doing, once you've braked.

This is how it is done.

The clutch is never depressed, while braking. The basic function of the clutch is to facilitate smooth changing of gears. When you brake suddenly, you are not changing gears, you're coming to a halt, or a slow crawl.

Some argue that it is necessary to press the clutch, because it is easier to do so, considering that the speed is shed so quickly and the correct gear must be chosen after. Some argue that it will stall, if you don't press the clutch, but that's untrue. if you are not quick to react, you are bound to stall.

So if you are not quick to react, pressing the clutch is the easy way out. But it isn't the correct way. If you can't react quick enough, then I'm sorry but, one is not fit to drive on the highway in the first place. Just because it is a simpler technique doesn't make it the correct technique. It's just the simpler way out.

It's not just about concentrating on several things at once. The braking and then depressing of the clutch should come naturally and in a reflex manner. First brake, when you're almost at a crawl, then engage clutch and switch gear. You say 99% of the drivers cannot concentrate on such things. there is nothing to concentrate on here, this should happen by reflex, like how one changes gear by reflex, or turns the steering by reflex.

If you need to concentrate on getting it right, then I'm afraid the highway is still not the place to drive, for you, and for 99% of the others.
Have you ever tried this? stalling is as forbidden as coasting in neutral. you said above "Some argue that it will stall, if you don't press the clutch, but that's untrue." you are mistaken here. i fail to understand how your car engine will still be running when you are in 5th gear and clutch is engaged! that's why i said, have you tried it?

Pressing clutch and brake simulateniously is a simplar and easier, you are right in that. but that is requirement in case of emergency, you don't want things complicated in already bleak conditions. that is simpler so, it eliminates the factors you should be caring for in those crucial moments.
Keep it simple and stupid! KISS approach!

and i don't undersatnd what is wrong in pressing clutch? no one tells that. they just say becasue i do it, he do it, other also doing it, i learned it, my father does it? what is all that? may be it is time to learn something new! something different! but i would also say if you are super quick and have been lucky to have traning like f16 pilots, then you can do whatever you like, and my respect for the same.

Last edited by Suess : 16th September 2011 at 12:52.
Suess is offline   Reply With Quote
Old 16th September 2011, 12:46   #235
Senior - BHPian
 
amitoj's Avatar
 
Join Date: Nov 2004
Location: Nashua, NH
Posts: 2,954
Thanked: 1,591 Times
Default Re: Driver ignorant of how ABS works; Turns Chevy Captiva upside down

This will be a good question to ask at Ford's Driving Skills for Life program this Sunday.
amitoj is offline   Reply With Quote
Old 16th September 2011, 13:15   #236
Senior - BHPian
 
vnabhi's Avatar
 
Join Date: May 2007
Location: DC -> DC
Posts: 5,265
Thanked: 1,233 Times
Default Re: Driver ignorant of how ABS works; Turns Chevy Captiva upside down

Quote:
Originally Posted by amitoj View Post
I am trying to recall what i have done under emergency braking.
I *think* what i have done is stood on the brakes first and foremost, then as speed has slowed down, pressed clutch to avoid stalling. I dont think i change gears though because both my hands are clutching the steering wheel!!
There is no right way or wrong way. Everyone will do what their instinct tells them to do.
That viewpoint matches with mine. I think pressing the clutch only when the vehicle comes to crawling speeds is the right thing, but I may be wrong.

Till speed drops to a point where we can change to 2nd gear, keeping both hads on the wheel to steer clear is the priority.
vnabhi is offline   (2) Thanks Reply With Quote
Old 16th September 2011, 13:18   #237
Senior - BHPian
 
Join Date: Apr 2008
Location: Dombivli
Posts: 2,626
Thanked: 1,191 Times
Default Re: Driver ignorant of how ABS works; Turns Chevy Captiva upside down

Let me share some of my personal experiences while braking:

Back when I learnt my driving in a Premier Padmini (diesel), I could never comfortably slow down the car to take it over the speedbreakers. The car would either be too slow or too fast. If it were too slow, it usually either stalled, or I had to bring it to a complete halt and then shift into first (no synchromesh) and then take the speedbreaker. If it were too fast, well, the jolt was noticeable. My uncle always scorned me for pressing the clutch too early and too often when slowing down.

When I started driving independently, I realized that the most effective braking can only be achieved when the clutch is not used for braking. Gradually I abandoned the habit of pressing the clutch when braking. No matter if it's a sudden, panic braking or a measured, gradual slowing down, I go for the clutch only when it's time to downshift. With practice I am confident I would be able to do a panic braking without stalling the engine most of the times.

Fortunately I never ever got into the habit of coasting in neutral and if I am not in gear, I am terribly uneasy. I shall put the car in fifth gear and coast without any accelerator input, but never EVER in neutral.

The cars: Premier Padmini diesel, Fiat Uno diesel, Maruti 800 MPFI, Santro and now the Ikon 1.6
honeybee is offline   (3) Thanks Reply With Quote
Old 16th September 2011, 16:26   #238
Team-BHP Support
 
suhaas307's Avatar
 
Join Date: Aug 2009
Location: Bangalore
Posts: 8,054
Thanked: 6,601 Times
Default Re: Driver ignorant of how ABS works; Turns Chevy Captiva upside down

Quote:
Originally Posted by anilisanil View Post
Ah! come on mate!...
...Whatever may be the answer, lets agree to disagree! To each his own!!
Quote:
Originally Posted by VeluM View Post
Sigh. Since you bring it up...


...I don't really like an argument in the midst of a healthy discussion, so let's just drop it.
Quote:
Originally Posted by Suess View Post
Have you ever tried this?...

...do whatever you like, and my respect for the same.
Alright guys, this is getting out of hand, and before it attracts moderator attention, let's leave it at this, please. We have different approaches to this. From what I have understood is that the clutch needs to be depressed ONLY when the gear needs to be changed. The rest of the time, our left foot must be on the dead-pedal, and the right should alternate between the brake and the accelerator, whenever whichever is necessary to be pressed.

When the need to brake suddenly arises, we press the brake and let the speed drop as fast as we can, and when the speed comes down and the RPM falls, the clutch needs to be pressed in order to prevent the car from stalling. Since it is emergency braking, the brake is depressed and held in its position (despite the violent ABS kickback) while the clutch has to be pressed almost immediately after, since the car falls out of power-band very quickly and the speed of the engine reduces drastically.

Is this approach wrong? If so, then please feel free to PM me and tell me what I am doing wrong and how I should correct myself. I'm just 22 years old and I have about 5 years and about 40k of driving experience in the city and on the highway. there is always scope for improvement and I'd like to get better and learn faster.

Although the clutch isn't supposed to be pressed along with brake simultaneously, while slowing down quickly, there is nothing wrong with it. By all means, follow what you feel is correct. I just believe that it is not the right way. I am not saying it's wrong. There is a grey area there. It doesn't necessarily have to be black or white, right or wrong.

Quote:
Originally Posted by amitoj View Post
This will be a good question to ask at Ford's Driving Skills for Life program this Sunday.
It will be a great question to ask. I'm really looking forward to it! Are you in the morning batch or afternoon batch?

Last edited by suhaas307 : 16th September 2011 at 16:30.
suhaas307 is offline   Reply With Quote
Old 16th September 2011, 17:34   #239
Senior - BHPian
 
VW2010's Avatar
 
Join Date: Dec 2010
Location: electricity
Posts: 2,566
Thanked: 2,040 Times
Default Re: Driver ignorant of how ABS works; Turns Chevy Captiva upside down

Quote:
Although the clutch isn't supposed to be pressed along with brake simultaneously, while slowing down quickly, there is nothing wrong with it.
I think one needs to press the clutch for losing the engine is not going to help steering with these modern power steerings.

The ABS is there for a reason and it definitely helps.

My brothers i10 gives me so much confidence in braking over my swift anyday.
VW2010 is offline   Reply With Quote
Old 16th September 2011, 17:40   #240
Distinguished - BHPian
 
SS-Traveller's Avatar
 
Join Date: Jan 2009
Location: New Delhi
Posts: 6,617
Thanked: 10,778 Times
Default Re: Driver ignorant of how ABS works; Turns Chevy Captiva upside down

Found this thread rather late, and I am to find 3+ pages full of esteemed BHPians propounding the practice of depressing both clutch and brake pedals together.

I consider one of the ultimate car driver's bible to be the Institute of Advanced Motorists' Advanced driving Guide (Do you want to be a better motorist? | Do you want to be a better motorist?) (yes, I have it) - and it clearly states (as do a lot of other driver training centres) that the clutch pedal is NOT to be depressed synchronously with the brake pedal during emergency braking procedures. Those who think otherwise may want to go through the links below:
LD System - Driving Lesson 5 Emergency Stop
Emergency Stop manoeuvre. Controlled Stop Manoeuvre. The Emergency / Controlled Stop is a manoeuvre that you mat be expected to perform on your Practical driving Test. Emergency Stop. Controlled Stop.


The appropriate action advised is...
Quote:
Just before the car comes to a stop press the clutch fully to the floor.
...and if one finds that the ECM has such a good anti-stall mechanism as to rev up the engine when one brakes without disengaging clutch, then either the ECM needs to be replaced, or the driver's right foot is so big it presses both brake and accelerator pedal together.
SS-Traveller is offline   (2) Thanks Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Palio 1.2 nv - Pressing the clutch pedal while starting the car kapilsharma80 Technical Stuff 24 18th February 2013 22:12
Xing: High rev when pressing the clutch during gear change raghu Technical Stuff 11 11th October 2009 07:06
cheen-cheen-cheen noise when pressing accelerator vebmetal Technical Stuff 15 27th August 2008 13:33
Which is the right Sequence Clutch-Brake Or Brake-Clutch ankura12 Technical Stuff 2 9th July 2007 10:02


All times are GMT +5.5. The time now is 08:09.

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