[Lorian]

Just to bring this back to driving for economy, the target for hypermiling always has to be to avoid pressing the brake pedal as much as possible, whatever foot you do it with.

Obviously braking to avoid others and maintain proper control of you car is very important, but the mindset needs to be "If I stop accelerating sooner, can I avoid some braking".

[Lorian]

Not sure we have mentioned weight of the vehicle much in this thread so far, but remember the lighter your vehicle, the less energy it requires to get it moving all the time.

This is not an excuse to leave the spouse and kids at home. "Sorry dear, its more economical if I leave you at home". However it certainly is if you are going to the shops 

Just to bring this back to driving for economy...

Thank you.

[eye30]

Air bag deployment

Taking the above one step further.
If you, the driver, have moved position then the air bag may deploy and you may hit the bag at its side.

By not being centered you may cause injury to yourself

[paul]

I prefer to go down hills in 4Th or 5Th (like the feel of a little engine breaking and prefer not to ride the brakes any more than I have to..)

i don't ride the brakes either

engine braking  huh
the engine braking in my diesel is all but non existant,
in a petrol maybe

[agentr31]

strange i find it pretty good in my 1.6 diesel... different driving styles perhaps?

[VFouR]

Parking
Where possible try to park facing downhill, and in spaces where you don't have to reverse in or out

Park facing downhill in a car park, let go of your open door and it "falls" into the car next to you. Or worse still there's into yours.
Park facing uphill and the doors at least fall closed.
In a car park never park adjacent to a car facing down hill.

[Dazzler]

Parking
Where possible try to park facing downhill, and in spaces where you don't have to reverse in or out

Park facing downhill in a car park, let go of your open door and it "falls" into the car next to you. Or worse still there's into yours.
Park facing uphill and the doors at least fall closed.
In a car park never park adjacent to a car facing down hill.

That's an interesting thought   (I am avoiding car parks altogether as much as I can)

[Ultralights]

i was thinking as i was reading these posts, no one has mention, until recently, weight!  the less the better,  dont carry so much shite around in your car! do you really need the tie down straps in the back if your not carrying anything on the roof! things like kayak holders on roof racks, or the roof rack themselves if they are easy enough to get on an off, (not including factory roof rails) what about CORRECT tyre pressures? not over inflated, you still want the car to behave correctly in an emergency, and fuel, its heavy, 0.8Kg per litre, so only fill half the tank if your only doing a short commute during the week.  oh, and keep air cleaners clean! regularly, petrol powered cars, replace leads and plugs often, they do break down over time and reduce spark strength slowly reducing burn efficiency  un-needed electrical accessories, all drain power, which means the alternator has a little bit more load on it. things like fog lights off, unless its actually foggy!   same as for batteries, my brothers landcruiser was using 25ltrs/100 km and they couldnt firure out why,  found one of its 2 batteries was dead, and the computer was running the alternator at max capacity trying to charge a dead battery all the time, changed battery, fuel consumption dropped back to its claimed 15 ltrs/100km.

[Dazzler]

Thanks for that  (some excellent input there) 

[constipated]

Slowing down
Remember the fuel pump cut-off. If you don't have a scanguage this is not obvious, but then you are decelerating don't dip the clutch and coast, keep the car in gear because the ECU turns off the fuel pump.

I was wondering about this especially with the diesel.

With my old petrol car you could slow down at a set of traffic lights in gear all the way to almost idle speed, even in 4th gear say. As long as you did not apply throttle, the car didn't seem to labour or be rough.

I notice with the diesel, there is a low pitched rumble and shuddering (like it is labouring) whenever in gear and lower than 1500rpm. If I try to do the same as in petrol car, even with no throttle applied, as the car slows down in gear to less than 1500, this rumbling begins. I'm not used to this sound so I always clutch it and then go into neutral, and instantly it goes away.

Is the car actually labouring despite no throttle? Is it better to go to neutral when it does this? Or is this a normal feeling/sound with the diesel and I should not worry?  I have read about diesel engines having a much longer ?stroke than a petrol engine and perhaps the shuddering having something to do with this as the revs drop even with no throttle applied?

Other diesel drivers care to comment?

I understand the benefit of slowing down in gear and fuel cut off, but the sound/feeling I get is uncomfortable coming from a petrol car.

[Dazzler]

You need to change down when this happens. It is a quirk of the diesel which improves a bit with more kilometres on the clock ...

When we had our CRDi I avoided going under 1500RPM in 4th and 5th for this reason but as the mileage got us this threshold reduced to 1300 or 1400RPM

[constipated]

You need to change down when this happens. It is a quirk of the diesel which improves a bit with more kilometres on the clock ...

So you think it is labouring.

It's funny about the diesel this way, how the petrol does not labour as long as you don't push the throttle and expect it to do work, whilst the diesel even with no load/throttle may exhibit this sign.

You need to change down when this happens. It is a quirk of the diesel which improves a bit with more kilometres on the clock ...

So you think it is labouring.

It's funny about the diesel this way, how the petrol does not labour as long as you don't push the throttle and expect it to do work, whilst the diesel even with no load/throttle may exhibit this sign.

It's because it is applying throttle for you. The diesels are designed to maintain idle even if under load. Actually, it holds at about 1100 rpm so it's some 300 revs above idle. In the lower 2 gears it has sufficient torque to climb quite steep hills by itself. 3rd goes OK on the flat but in 4th or 5th it tries but is unable to pull at the low revs.

You will find that you need to drive considering the lowest speed in each gear more than with a petrol. This means pretty much means keeping out of the 1000-1500 rev band in anything other than 1st and 2nd and not coasting to a stop in 4th lower than 1100 revs else the engine will attempt to maintain drive.

I change down to 3rd or even 2nd when stopping which helps to mask this idiosyncrasy and helpfully provides a little extra engine braking.

Do a search here for "anti-stall" for discussion on this feature.

[constipated]

You will find that you need to drive considering the lowest speed in each gear more than with a petrol. This means pretty much means keeping out of the 1000-1500 rev band in anything other than 1st and 2nd and not coasting to a stop in 4th lower than 1100 revs else the engine will attempt to maintain drive.

I notice this anywhere below 1500rpm. Is the anti stall operating even at this level? I see that I should either slow down in neutral or change to a lower gear. I've been noticing driving the manual is more work because of this. Need to think more. Not quite as instinctive as it was with my petrol. I guess I'll adapt as I get more used to it.

Very interesting this anti-stall feature. Is this a feature of all diesels or just the i30?

The engine will loosen up quite a bit as Dazz said which will allow a little more use around 1500 rpm but it won't ever really have enough torque below 1500 in 4th and above to be useful but will on the other hand limit how slowly you can go in any given gear without getting an unwelcome push from the engine. Try this: engage first and idle along then try braking against the engine to slow down. You will discover that this feature will fight you very firmly. Best to discover this before it surprises you when trying to slow down half way around a roundabout in 3rd.

Old (truck) diesels I believe had the idle regulated mechanically with some sort of centrifigal governor.

You will get used to it... and find it is actually quite useful when trundling along in traffic etc. It also makes for the simplest of take offs... just let out the clutch initially while still idling and then apply accelerator. And it's really terrific for (non) handbrake starts on hills.

Once you work it out and realise where it can be used to advantage it will grow on you.

[Dazzler]

Great description Pip 

I also really liked that feature when I got used to it(almost impossible to stall... Some of our petrol i30 owners find the petrol model quite easy to stall (The wife's petrol CW seems ok though )

[Rochdale Pioneers]

Sorry to resurrect an old thread, but as I'm now getting a stable 49-50mpg from my 1.4 I've probably got a few tips to pass on.

1. Setting off. Switch on only when you can pull away immediately from a parking space you picked to let you go straight out. Shift up at 2,000-2,500 depending on the road and the gradient, accelerating briskly to your cruise speed.

2. In town. Look ahead! Don't accelerate if you're going to catch up on traffic or a red light. You're looking to conserve as much momentum as you can - trundling along on the flat at 30mph uses very few horsepower so should be nice and efficient. Back off the gas more than you use it - you can almost always keep going roughly as quick as you are with a bit less throttle.

3. Pre-brake. As we want to conserve momentum it can often be better to brake earlier than whatever it is you need to brake for (such as a red light) as its likely it can change to green before you get there. Starting to accelerate again in 3rd gear at 15 mph having not stopped is far more efficient than stopping and starting again.

4. Coast in Neutral as much as possible. The tiny amount of fuel burned at tick over vs coasting in gear is worthwhile, because you roll further out of gear. Basically coast up to everything - lights, roundabouts, that empty parking space at the back of the car park. Coast down hills. Coast between gears. The 255mpg my car does at tick over does wonders for overall economy.

5. Drive with load. Where you need to torque your way up a hill, set a throttle position and stick to it. You'll slow a touch uphill, balance this off by going a little faster down hill. Similarly if you know the road and there's a nice downhill you can coast down, accelerate faster than your normal cruise speed under load then drop into neutral for the coast. And set a cruise speed that's efficient. I don't cruise faster than 65mph (which in practice means doing 60-70 as I pulse accelerate then coast).

Hope this helps. Have been astonished how efficient this car can be when driven in the right way...

[Dazzler]

Hi RP..

Thanks for that.. Not sure about the being in Neutral bit though.. I'm sure that has been debated on here and there are as many for it as against it...

Some  consider it downright dangerous (will be interested to see what others say)

Did a Google search and quite a bit of discussion on the net (with valid comments for and against)

[Phil №❶]

Although our cars are autos, in a manual I wont use neutral at all while moving especially down hill. This puts 100% of the breaking load on the brakes, allows the car's speed to increase, requiring more braking and heated brakes and provides no emergency drive or acceleration should it be necessary.

It is indisputable that fuel can be saved by coasting, but the safety reductions clearly outweigh the advantages IMO.

Although our cars are autos, in a manual I wont use neutral at all while moving especially down hill. This puts 100% of the breaking load on the brakes, allows the car's speed to increase, requiring more braking and heated brakes ...

Ok, here we go again. Phil, your response indicates you do not understand how that technique ought to be employed. In which case you are probably right to ignore it.

I use all the gears in my car along with neutral. I rarely need to touch the brakes and that IMO is the most vital part of driving economically. I.e., not wasting fuel heating the brakes. Similarly, allowing the engine to slow the car on the overrun is also indirectly using fuel, in this case to pump air through the engine. This is not offset significantly by the use of no fuel in this mode. Of course, engine braking is the preferred method when you need to slow due to traffic etc, brakes are last resort.

I saw an article some time back about the latest gearbox design for trucks. It used sensors to determine attitude (and other stuff, I don't remember all the details) and the gearbox processor intelligently used coasting in neutral as appropriate to improve economy. In other words it was doing what is proposed here with less intelligence than the average driver. It offered significant fuel savings.

The whole idea when trying to improve economy is to limit fuel used to gain momentum (which most people seem to understand) but then and probably more important, is to not waste it. Engine braking and foot braking are the enemy.

BTW just about to buy fuel, 1200+ on trippy and didn't start with a fully brimmed tank.

I wish to deal with coasting in gear and the fuel, used as opposed to coasting in neutral.

It is my experience by observing the fuel, used when coasting that it is better to coast in gear in the diesel vehicles we own.  According to the Scangauge in the i30 CRDi and the real time fuel consumption readout in the ix35, when coasting their is 0 fuel being used by the vehicle, provided you foot is off the accelerator. 

If this is correct, and I have no reason to doubt the readout I am seeng, coasting down hill in gear has the added advantage of engine breaking.  I have driven this way in the i30 for just under 5 years, done 154 000 km and have not needed to replace the break pads, evidence that sensible engine breaking reduces the need for direct breaking and at he same time, helps to conserve fuel.

Modern diesels with electronic fuel injection from common rail controlled by a myriad of sensors via an ECU can shut off fuel delivery when coasting and begin delivering fuel when required to keep the engine turning over.

Those of you who know the SE freeway from the top of the range into Adelaide will realise that, if I am correct, almost no fuel is used with minimal need for breaking.  Observation of the Scangauge on the way down shows that fuel usage remains at 0 for the majority of this journey of 9km.

This information (link included) confirms what I have discovered through personal observation.

Coasting
Although it used to be quite a common practice to save fuel, rolling downhill or approaching a junction with the car out of gear is inadvisable because the driver doesn't have full control of the vehicle

You lose the ability to suddenly accelerate out of tricky situations.
You lose engine braking which risks brake fade on downhill stretches – overheated brakes require harder pedal pressures to stop the vehicle.
With changes in vehicle fuel systems coasting won't save you fuel these days either.

Old car with a carburettor – take your foot off the accelerator pedal with the car in gear and fuel is still drawn through into the engine. Fuel savings could be made by coasting out of gear.
Modern car with electronic engine management – fuel and ignition systems are effectively combined and controlled by one Electronic Control Unit (ECU). Take your foot off the accelerator and the ECU cuts the fuel supply to the injectors anyway so there's nothing to be gained by coasting.
Modern diesel engines also have the ability to shut off the fuel when you take your foot off the accelerator.

http://www.theaa.com/motoring_advice/fuels-and-environment/drive-smart.html

Tis website gives great information about driving economically.  I have quoted just a small part of the available advice and information.

[Dazzler]

Thanks Bob and Pip, I guessed you might both put forward some worthwhile arguments 

[Doggie 1]

I don't agree with coasting in neutral.
I consider it to be a dangerous practice as you have little control of the vehicle should you require it in an emergency.
I taught both of my girls not to do it when I was teaching them to drive.

I wish to deal with coasting in gear and the fuel, used as opposed to coasting in neutral.

It is my experience by observing the fuel, used when coasting that it is better to coast in gear in the diesel vehicles we own. 
No not "better" but an alternative mode that is better in some circumstances.

According to the Scangauge in the i30 CRDi and the real time fuel consumption readout in the ix35, when coasting their is 0 fuel being used by the vehicle, provided you foot is off the accelerator. 
Correct, I did say that.

If this is correct, and I have no reason to doubt the readout I am seeng, coasting down hill in gear has the added advantage of engine breaking.
Correct, but only an advantage if you wish to slow or maintain speed. Otherwise a disadvantage as I said before because you will waste momentum.

I have driven this way in the i30 for just under 5 years, done 154 000 km and have not needed to replace the break pads, evidence that sensible engine breaking reduces the need for direct breaking and at he same time, helps to conserve fuel.
A good result.

Modern diesels with electronic fuel injection from common rail controlled by a myriad of sensors via an ECU can shut off fuel delivery when coasting and begin delivering fuel when required to keep the engine turning over.
Correct.

Those of you who know the SE freeway from the top of the range into Adelaide will realise that, if I am correct, almost no fuel is used with minimal need for breaking.  Observation of the Scangauge on the way down shows that fuel usage remains at 0 for the majority of this journey of 9km.
This is a good example of when coasting in gear is correct.

This information (link included) confirms what I have discovered through personal observation.

Coasting
Although it used to be quite a common practice to save fuel, rolling downhill or approaching a junction with the car out of gear is inadvisable because the driver doesn't have full control of the vehicle
I don't think a blanket statement can cover all situations.

You lose the ability to suddenly accelerate out of tricky situations.
So keep it in gear if it's tricky.

You lose engine braking which risks brake fade on downhill stretches – overheated brakes require harder pedal pressures to stop the vehicle.
That's the whole point misunderstood in this statement. The idea is to avoid engine braking when you don't need to maintain speed or slow down.

With changes in vehicle fuel systems coasting won't save you fuel these days either.
This is just wrong. You will use less fuel when coasting in gear but when balanced with the momentum loss you may use more fuel.

Old car with a carburettor – take your foot off the accelerator pedal with the car in gear and fuel is still drawn through into the engine. Fuel savings could be made by coasting out of gear.
Irrelevant here.

Modern car with electronic engine management – fuel and ignition systems are effectively combined and controlled by one Electronic Control Unit (ECU). Take your foot off the accelerator and the ECU cuts the fuel supply to the injectors anyway so there's nothing to be gained by coasting.
Again, presupposes the idle fuel used will be greater than that saved by maintaining momentum.

Modern diesel engines also have the ability to shut off the fuel when you take your foot off the accelerator.


http://www.theaa.com/motoring_advice/fuels-and-environment/drive-smart.html

Tis website gives great information about driving economically.  I have quoted just a small part of the available advice and information.

[rustynutz]

My eyes! My eyes! 

Any chance of changing that blue to something a bit more eye friendly, pip?   

[Dazzler]

My eyes! My eyes! 

Any chance of changing that blue to something a bit more eye friendly, pip?   

Is that better Rusty? (Hope you don't mind Pip) 

I taught both of my girls not to do it when I was teaching them to drive.

Likewise, I never tried to teach my son what is an advanced technique fraught with danger if the driver is unable to properly understand it, let alone get it right.

And after 5 years of driving he has become a very capable driver. He changes gears exactly when and as required and even displays excellent understanding of traffic flow and reacts well ahead of time to situations - for which of course, I take credit.

Still I see no need to make any changes. Economy is not a biggie for him.

My eyes! My eyes! 

Any chance of changing that blue to something a bit more eye friendly, pip?   

Is that better Rusty? (Hope you don't mind Pip) 

Thanks, that was a shocker.

[Doggie 1]

I taught both of my girls not to do it when I was teaching them to drive.

Likewise, I never tried to teach my son what is an advanced technique fraught with danger if the driver is unable to properly understand it, let alone get it right.

And after 5 years of driving he has become a very capable driver. He changes gears exactly when and as required and even displays excellent understanding of traffic flow and reacts well ahead of time to situations - for which of course, I take credit.

Still I see no need to make any changes. Economy is not a biggie for him.

I don't see it as an advanced technique, just a dangerous technique.
It's not about getting it "right" because there is no way to get it right.
When you are travelling in a car at 60, 80 or 100 km/h or whatever, without it being in gear, the fact is you are not in control, the laws of physics are.
You can steer and you can brake but you need the full trifecta to have proper control.
Anyone can do it, but I just wouldn't recommend it as a safe driving practice.