[Sudipto-S-Team]

Yes Andro. It's a kind of buying time and liberation from jams with some petrol.

[Xehaust]

I feel that it should be for a 60-90 sec signal. I do this quite often though not all the times.
To me, its not about saving money or petrol but more of a "being environmentally friendly" thing so as to reduce my individual carbon footprint.

[hrag]

Flame me if you will, but I never switch off my engine (and A/C) at traffic signals, railway crossing gates etc. My bike idles away as well at lights. Railway crossing gates, when closed and encountered during a motorcycle ride, are an opportunity to get off and get some blood back in one's gluteal muscles.

Any propensity of the engine to die while idling indicates a problem that needs to be fixed.

[dadu]

Yes and I will work very conservatively in my calculations on this, based on studies in Japan & US.

A study on fuel savings on idling stops in japan came out with a figure of 13.4% savings under Urban conditions for passenger cars and 19% for buses. I will take it as a conservative 10% for passenger cars in India.

In US, the added cost due to wear on the engine parts related to restarting the engine many times, in order to save fuel was reported at $10 per year. I will take this at 15$ for India i.e. 600Rs apprx.

I will again take a conservative example of a Diesel SUV like Safari which gives a FE of 10 in the city and diesel costs at 50Rs in a city like bangalore with an annual running of 10,000 Km's.


Now the Calculations with engines running at stops(Annual costs) :

Diesel required in an year : 10,000 / 10 = 1000 ltrs
Cost of Diesel used : 1000 * 50 = Rs 50,000/-


Now the Calculations with engines switched-Off at stops(Annual costs) :

FE increases by 10% i.e. 11Km/ltr

Diesel required in an year : 10,000 / 11 = 909 ltrs
Cost of Diesel used : 909 * 50 = Rs 45,454/-

Savings : Rs 4545/-

Less wear & tear/ maintenance cost @Rs600/- = Rs 4000/- (rounded)

Now how many of us spend Rs 4000/- annually on the maintenance of only the starter motor and battery ??? and that too on these conservative figures.

Dont forget that the first 2 years are totally covered under warranty for new vehicles and if you have a more FE vehicle, you save more than the calculations shown above.

Originally Posted by hrag

dadu, I hear what you're saying regarding warming the engine up but unless I see some numbers, I find this hard to believe - that frequent starts have little impact on the battery and the starter motor.

Plus, I'd like to see some numbers around FE where one does not switch off at all versus the switch-off-at-every-signal types.

You should not switch-off if its a slow moving traffic but you should in case of traffic light stops.

And not to forget a small contribution you make towards the greenhouse gases and the environment by switching-off if your idling is more than 15 seconds.

I have started following this, you should too.

Originally Posted by androdev

one thing to remember is traffic doesn't come to stand still at most of the signals (except the ones that are longer than 120 seconds) instead the traffic creeps forward in an extremely irritating manner. and if you switch your car off and the guy behind you finds that the traffic in front of you has moved a millimeter, he is going to honk the heck out of you.

frequent start/stop (unless 120seconds longer) is not worth it. the parts cost lot more than fuel.

[vnabhi]

Originally Posted by androdev

one thing to remember is traffic doesn't come to stand still at most of the signals (except the ones that are longer than 120 seconds) instead the traffic creeps forward in an extremely irritating manner. and if you switch your car off and the guy behind you finds that the traffic in front of you has moved a millimeter, he is going to honk the heck out of you.

Well said, androdev. This is the grim reality in most traffic junctions at Hyd too. However, I decide to switch off the engine only if I am pretty sure that the cars ahead can no longer inch forward. However I follow a 1 minute rule to switch off, if less I don't switch off.

[hrag]

dadu, the numbers do look impressive on paper but what I'd like to see are real-life figures. Let's say you (or anybody else) with actual data. In an Initial Ownership Report or a Long Term Ownership Report.

[VBV]

I think 15 secs as a heuristic is actually not that accurate. I'd rather have it on cc. For eg., all 1.6L engine cars with MPFI will save if switched for more than 20 secs. Its difficult to believe in one number, since the consumption at idling would not be uniform across engines.

[spadival]

I switch off at red signals if the counter shows around 20-30 seconds. Thats the least I can do to save fuel.

[knownstrangerr]

I do agree that switching off the engine at signal help in various ways,but in places like chennai where vehicles keep creeping even in the signal its really not possible,if we worry about FE and greener environment the vehicles behind you honk and force you to keep moving .I guess most drivers in chennai would agree to this

[dadu]

The FE increase %age value is not taken from a theoritical paper but an actual field test conducted by the Japanese.

- Three vehicles of a 2000 cc wagon of the same type were used.

- Three male professional drivers participated. Their ages ranged from thirties to forties, they were instructed to carry out idling stops as much as possible while taking care of safety.

- During the test, they rotated driving vehicles and changed the order of vehicles in the platoon to cancel the differences in driver’s characters.

- Also, air pressure of the tires and the weights of the vehicles were adjusted to be identical.

- Each vehicle ran simultaneously about 3,717 km total and the same route so that driving conditions were identical.

So the figures are real life and I dont want to reinvent the wheel. There will be variances in the results due to the test environment/ country but cannot be drastic, i already took conservative figures.

Originally Posted by hrag

dadu, the numbers do look impressive on paper but what I'd like to see are real-life figures. Let's say you (or anybody else) with actual data. In an Initial Ownership Report or a Long Term Ownership Report.

The US reports state "10 seconds of idling can use more fuel than turning off the engine and restarting it."

You cause more damage to the engine under idling than running.

Originally Posted by VBV

I think 15 secs as a heuristic is actually not that accurate. I'd rather have it on cc. For eg., all 1.6L engine cars with MPFI will save if switched for more than 20 secs. Its difficult to believe in one number, since the consumption at idling would not be uniform across engines.

[DieselFan]

each start is highly stressful for the engine itself and brings down the life of an engine. This important point should also be kept in mind.

[muralisk]

Off late, I am switching off the engine at traffic lights and other traffic jams if I think I would be stationary for more than 15 secs. Here is some information that I had got from Internet on Idling Myths & Facts
Myth 1: The engine should be warmed up before driving. True, the engine must be warmed up, but idling is not an effective way to warm up your vehicle, even in cold weather. The best way to do this is by driving the vehicle. With today’s modern engines, and the advent of electronic engines, you need no more than about 30 seconds of idling before driving away, even on the coldest winter days. Driving a vehicle cuts warm-up times in half. This reduces fuel consumption and greenhouse gas emissions. Every 30 minutes of idling costs you at least 2/10 (0.2) of a gallon of gas - and up about 7/10 (0.7) of a gallon for an 8-cylinder engine. Keep in mind that every gallon of gas you use you also produce about 19 pounds of carbon dioxide.

The catalytic converter - the device that cleans pollutants from the vehicle exhaust - does not function at its peak until it reaches between 750° and 1500° F. The best way to warm the converter is to drive the vehicle. Idling emits more pollution if the catalytic converter is not working properly.

In winter conditions, emissions from idling vehicles are more than double the normal level immediately after a cold start. Warming up the engine means more than just the engine. The tires, transmission, wheel bearings and other moving parts also need to warm for the vehicle to perform well. Most of these parts do not warm until the vehicle is driven.

It‘s important to drive away as soon as possible after a cold start just avoid high speeds and rapid acceleration for the first 3-5 miles. This lets the whole vehicle reach peak operating temperature as quickly as possible without paying a fuel penalty.

If your vehicle has a diesel engine, idling actually lowers the coolant temperature faster than shutting off the engine. In other words, switching off the engine keeps the engine warm longer.

Myth 2: Idling is good for your engine. Excessive idling can actually damage your engine components, including cylinders, spark plugs, and exhaust systems. An idling engine is not operating at its peak temperature, which means that fuel does not undergo complete combustion. This leaves fuel residue that can condense on cylinder walls, where they can contaminate the oil and damage parts of the engine. For example, fuel residues are often deposited on spark plugs. As you spend more time idling, the average temperature of the spark plug drops. This makes the plug get dirty more quickly, which increases fuel consumption by 4 to 5 %. Excessive idling also lets water condense in the vehicle’s exhaust, leading to corrosion and a reduction of the life of your exhaust system.

When not actively driving, people tend to idle their cars largely for one of two reasons: either to warm up the engine before driving or to avoid wear and tear on the engine in situations that require frequent restarting, such as drive-through service lines, rail crossings, car wash lines, carpool lines, and departure from concerts and sporting events, or while talking to friends or using the cell phone. By understanding the effects of idling and reducing the practice, you can improve your car’s performance, save money, and reduce needless carbon dioxide emissions.

Myth 3: Shutting off and restarting your vehicle uses more gas than if you leave it running. The bottom line is that just 10 seconds of idling uses more fuel than restarting the engine. As a rule of thumb, if you are going to stop for 10 seconds or more - except in traffic - turn off the engine. You’ll save money, and you won’t produce harmful Carbon Dioxide, the leading greenhouse gas.

Idling gets you nowhere - and it can be costly. Excessive idling wastes an enormous amount of fuel and money and generates needless greenhouse gas emissions.

Restarting a car many times has little impact on engine components such as the battery and the starter motor. The wear on parts that restarting the engine causes adds about $10 a year to the cost of driving - money that you’ll likely recover several times over in fuel savings.

Fact: Idling adds to global warming. Climate change is a serious threat to the planet caused mainly by burning fossil fuels, such as gasoline. Overwhelming scientific evidence links global warming to the earth’s highest ever average annual temperatures, melting polar ice caps, rising sea levels, increasingly severe weather events, and to the threat of many plant and animal species.

Fact: Idling does affect the environment. Keep in mind that every gallon of gas you use produces about 19 pounds of carbon dioxide.

Fact: Idling contributes to respiratory illness. The emissions of even today’s modern vehicles contain Carbon Monoxide, Nitrogen Oxide, Sulfur Dioxide, Benzene and several other toxic chemicals that impair our lungs and heart. Prolonged exposure can lead to death. Children, the elderly, and individuals with asthma are especially at high-risk.

Fact: Idling can harm our health. Children are particularly vulnerable to air pollution because they breathe faster than adults and inhale more air per pound of body weight. Many people believe that they are protected from air pollution if they remain inside their vehicles. Not so according to a report by the International Center for Technology Assessment (CTA). CTA found that exposure to most auto pollutants, including volatile organic compounds (VOCs) and carbon monoxide (CO), is much higher inside vehicles than at the road side. VOCs and CO are linked to serious health problems -- like respiratory infections and cancer -- are known to shorten life. The highest exposure occurs when sitting in traffic congestion on highways or in a line-up of idling vehicles at a school or drive-through. Idling is linked to increases in asthma, allergies, heart and lung disease and cancer.

Fact: Idling wastes fuel. In this time of ever increasing gas prices, needless idling burns your hard earned dollars through your exhaust pipe. And remember that fossil fuels are a non-renewable resource and are being depleted in the face of ever increasing world demand.
- Idling your vehicle for more than just 10 seconds uses more fuel than restarting your engine.
- Idling your vehicle for just 10 minutes can use as much fuel as it takes to travel 5 miles.
- Idling your vehicle for 10 minutes a day uses more than 27 gallons of fuel a year.

Fact: Idling wastes money & natural resources. Thirty seconds of idling can use more fuel than turning off the engine and restarting it. If you are stopped for more than thirty seconds - except in traffic - turn off your engine. An idling car is the most inefficient car on the road -- it gets zero miles per gallon. Turning off your car will save gas and money. Idling for one hour burns nearly one gallon of gasoline.

Fact: Idling damages engine components in our vehicles.Idling is not an effective way of warming up your engine, as your vehicle is made up of many moving parts. To properly warm your vehicle’s transmission, tires, suspension, steering and wheel bearings, you need to slowly drive-off.

An idling engine is not operating at peak temperature, resulting in incomplete fuel combustion. Fuel residues can condense on cylinder walls, contaminate oil and damage engine components. With more engine idling these residues tend to deposit on spark plugs. The resulting plug fouling can increase fuel consumption by 4 to 5 %.

Excessive idling can also cause water to condense in the vehicle’s exhaust. This can lead to corrosion and reduce the life of the exhaust system. On the other hand, frequent restarting has little impact on engine components such as the starter motor and the battery.

A poorly tuned engine uses up to 15 % more energy when idling than a well-tuned vehicle. Keeping your vehicle in good condition is a key to fuel efficiency and reduced greenhouse gas emissions. Idling your vehicle with the air conditioner on (to keep the interior cool) can increase emissions by 13 %.

[hrag]

dadu, I believe your figures from Japan. All I'm asking for now is for someone to put up their Indian FE figures for 2 runs of the same route. One without switching off and one with. Should be easy enough over 2 tankfills.

How does idling damage the engine? Especially a warmed up engine that is idling at a traffic light?

Edit: I'm not disputing the fact that idling consumes fuel. I'm merely saying I would rather idle than take a risk of the battery and starter motor take a beating.

[dadu]

Originally Posted by muralisk

An idling engine is not operating at peak temperature, resulting in incomplete fuel combustion. Fuel residues can condense on cylinder walls, contaminate oil and damage engine components. With more engine idling these residues tend to deposit on spark plugs. The resulting plug fouling can increase fuel consumption by 4 to 5 %.

Excessive idling can also cause water to condense in the vehicle’s exhaust. This can lead to corrosion and reduce the life of the exhaust system.

Already mentioned by Murali above.

Originally Posted by hrag

How does idling damage the engine? Especially a warmed up engine that is idling at a traffic light?

In the end it boils down to the maintenance cost, in which case my calculation method can help determine your Fuel savings Vs maintenance cost of battery/starter every year.

Originally Posted by hrag

Edit: I'm not disputing the fact that idling consumes fuel. I'm merely saying I would rather idle than take a risk of the battery and starter motor take a beating.

[hrag]

I will not comment on the FE saving until I see some Indian data.

So what does the temperature gauge show? When I idle at a traffic light, my temp. gauge needle should drop? Drastically? Because it is idling and not operating at peak temperature?

Gentlemen, all I'm saying is - If you have tried it yourself and then show data, things become easier to believe.

Edit: with not switching off at every signal, my OEM Exide battery was replaced at ~39 months / 60,000 km. The battery died because a regulator failure was not looked into in time. The replacement Amaron (with the same idling habit) has been with me for ~26 months / 30,000 km. My starter motor has never given me trouble. I don't know how green the grass is on the other side.