Coasting

[gumdrop]

I guess the emissions test involves changes in speed, in which case coasting would result in theoretical (laboratory) savings in consumption and thus a lower CO2 figure to boast about.

I have noticed engine braking (zero consumption) seems to be recognised and give a better 'range' boost than freewheeling (which still requires ide fuel consumption) that's why I believe it's the figure on the windscreen that's behind it; plus it's something to add in the endless list of features in the brochure.

To me it's just another sign of desperation for the lowest emissions figure from an unrealistic rolling road.

The 308 is getting close to a fill after 975km with 150 range still showing - 53L tank - 70p/L

The 2008 gets ~ 28 km/L (1400km fm 50) - 62p/L

I don't bother with coasting as fuel is dirt cheap currently.

I have to remember to de-select cc down steeper hills or it will engage lower gears to maintain the set speed.

Just rambling on.......

 

Fuel is dirt cheap (sorry was) but coasting might save money on gearbox and brake wear?

[ejstubbs]

I'm still struggling to understand why coasting is seen as a good thing to do.  The manual says you can do it, but it doesn't say anything about why you would want to.  Does it really disengage the drive?  If it does then doesn't that mean that the ECU has to send fuel to the engine to keep it ticking over, rather than allowing it to keep spinning on the overrun and not requiring any fuel?

 

I also agree with TruckbusUK: I was always taught not to coast because it reduces your control over the vehicle.  I'm pretty sure that it counted as an error during the test as well.  (Though what they can do if the car does it for you isn't clear.  And, indeed, what if you happened to be taking your test way way back when cars like the Saab 96 and two-stroke Wartburgs had a freewheel within the transmission?)

[Ryeman]

All these fangled devices are for lower CO2 emissions in a test cell I suspect.

Safety now comes second to maintaining full control it seems.

I wonder what an examiner would say if you knocked the gear leaver into neutral and coasted then stalled the engine on a roundabout or railway crossing.

I'm not sure how coasting could save your brakes.........I assume tapping the brakes reengages the gears.

[ejstubbs]

If coasting doesn't save fuel (which all up-to-date informed advice I've found eg here says is the case) then it won't reduce CO2 emissions either.

 

Could it actually be to do with other emissions eg keeping the engine burning fuel so as to keep some part of the exhaust system hot in order for other exhaust gases (dare I suggest NOx?) to be catalysed or otherwise reduced?

Edited 13 October, 2016 by ejstubbs

[Ryeman]

We know how much the emissions engineers know about the programmed test procedure from their work on the 'cheat' and I wonder if the coast function achieves something there but not on the road.

Like 9/10 speed gear boxes, do we really benefit or is it all about that much quoted figure.

[gumdrop]

Land Rover and Saab had a freewheeling facility years ago.

[ejstubbs]

AIUI the purpose of the freewheel on the original Land Rover was to avoid transmission wind-up from the full-time 4WD system.  Early Saab's were two-strokes, same as the Wartburg, and had freewheels for the same reason: two-strokes don't like being on overrun for extended periods as they rely on the fuel/oil mixture for lubrication and can seize if run with the throttle closed for too long.  Why Saab persisted with the freewheel on some of their early four-strokes in less clear - it may simply have been to avoid the cost of developing a new transmission.

[g6zru]

I'm still struggling to understand why coasting is seen as a good thing to do.  The manual says you can do it, but it doesn't say anything about why you would want to.  Does it really disengage the drive?  If it does then doesn't that mean that the ECU has to send fuel to the engine to keep it ticking over, rather than allowing it to keep spinning on the overrun and not requiring any fuel?

 

I also agree with TruckbusUK: I was always taught not to coast because it reduces your control over the vehicle.  I'm pretty sure that it counted as an error during the test as well.  (Though what they can do if the car does it for you isn't clear.  And, indeed, what if you happened to be taking your test way way back when cars like the Saab 96 and two-stroke Wartburgs had a freewheel within the transmission?)

I had a Wartburg Knight Estate, my first new car. I'm convinced that the combination of freewheel and atrocious brakes improved my driving by having to anticipate what was happening around me. Didn't do much for my blood pressure tho'. 

 

Fred

[SurreyJohn]

I have a 66 plate 1.2 DSG SEL and cannot see the coasting function in any of the menus, so unless its enabled through VCDS it looks like the 1.2 DSG version doesn't have it

I don't appear to have it either on my 66reg 1.2 DSG SE, so agree must be engine specific

Edited 15 October, 2016 by SurreyJohn

[andyspan]

I had a Wartburg Knight Estate, my first new car. I'm convinced that the combination of freewheel and atrocious brakes improved my driving by having to anticipate what was happening around me. Didn't do much for my blood pressure tho'. 

 

Fred

When working as a mechanic more years ago than I care to remember I went on a test drive in a customers Wartburg Knight and hurtled into a corner expecting a little engine braking but no, nothing..............heart in mouth and a great laxative    

[longedge]

I had a Rover 75 (IIRC) - it used as much oil as petrol. It had free wheel which you could select when in gear and pulling and vice versa. Nearly wrapped myself around a number of roadside objects when using it.

[Coaster390]

I don't appear to have it either on my 66reg 1.2 DSG SE, so agree must be engine specific

I have a 2.0L SE L, 65 plate and mine has it. It doesn't alway come on though.

[Ootohere]

So all those that so far have said they have 'coasting' have diesel engine vehicles. 

Those without have TSI petrols, so not that much of a surprise then.

[willl]

So all those that so far have said they have 'coasting' have diesel engine vehicles. 

Those without have TSI petrols, so not that much of a surprise then.

Not true for all TSI petrol engines. I've got a 1.4l 92kw TSI petrol engine and I've got coasting.

[Ootohere]

Sorry, i had not spotted your post. @ #17

 

Is the feature on yours due to being in Australia, 

or are there also 1.4TSI Yeti sold in Europe with Coasting does anyone know?

Edited 23 October, 2016 by Offski

[willl]

Sorry, i had not spotted your post. @ #17

 

Is the feature on yours due to being in Australia, 

or are there also 1.4TSI Yeti sold in Europe with Coasting does anyone know?

Possibly, I'm not sure. I know my model was never sold in the U.K., but was on sale elsewhere in the EU. Skoda sales (and Yeti more so) are quite low in this country (compared with other manufacturers here and compared to Skoda/Yeti sales over there so we are probably just getting things sold in Europe with little to no modifications made. In fact, when I picked up the car was given a seperate owners manual supplement that has things to note for Australia that aren't mentioned in the main one.

The 1.4TSI sold in the U.K. has more HP than mine. However, I'm aware that my 1.4 is no longer sold locally. They've replaced it with a 4x4 1.4 TSI with the same kW and HP rating as the one sold in the U.K.

[basssolo]

 

 are there also 1.4TSI Yeti sold in Europe with Coasting does anyone know?

My 2015 1.4tsi L& K does not have coasting option

[willl]

My 2015 1.4tsi L& K does not have coasting option

That reminds me, when I went to test drive the Yeti, it was a MY15, which did not have coasting. My MY16 does though, so I think it's a recent change.

[threadbear]

I have always associated "coasting" as a bad habit of driving?

 

Stop/Start makes sense as when stationary at traffic lights you are meant to be in neutral with hand brake on anyway rather than siting there "riding" the clutch like so many people do. 

 

I always use stop/start unless the traffic is a continually stop/start moving queue in a traffic jam etc. Coasted? Never. 

[willl]

From the mild hybrid section of this article: http://www.volkswagenag.com/content/vwcorp/info_center/en/themes/2014/11/Innovation_workshop_2014/CO2_reduction.html

Mild hybrid technology from Volkswagen shuts off the combustion engine in coasting phases – such as when the driver takes the foot from the accelerator pedal either on descents or when anticipating a stop. It creates an alliance of efficiency, comfort and convenience. The engine, which is joined to a dual-clutch gearbox (DSG), is restarted very comfortably via a belt-driven starting generator (RSG).

When the engine is shut off, it is disengaged from the drivetrain which enables a "coasting" mode in which the car is driven with zero emissions. In this case, the text message "Coasting" appears on the multifunction display and the familiar symbol for the active "stop-start system". This "coasting with engine-off function" extends the availability of the "stop-start system" to any driving speeds. An important difference: In today's stop-start systems, the engine must first reach zero revs before it can be restarted. However, in the Volkswagen mild hybrid (a low-voltage system) the engine can be restarted at any engine speed ("change of mind situation"). So, this system conveniently is able to smoothly handle situations such as when the driver releases the accelerator pedal, but then suddenly presses it again, e.g. to get through an intersection while the traffic light is still yellow. An electric oil pump in the DSG also ensures that the gearbox can still shift while the combustion engine is deactivated, so that the proper gear ratio is immediately available at restart.

In addition, the amount of energy recovered by regenerative braking has been significantly increased in the mild hybrid. A lightweight lithium-ion battery serves as the energy storage device here. The recovered energy in the mild hybrid is not only used to supply the vehicle electrical system during stop-start and coasting mode phases – and to restart the engine. It is also used for what is known as the mini boost. This shifts the engine's load point which further reduces CO2 emissions.

[Defenderben]

Is coasting not automatically activated when you go round in "ECO" mode?

It is on my Diesel DSG and was the same on my Petrol Golf R DSG, too.

Or are you not able to select different modes?

Edited 26 October, 2016 by Defenderben

[Ryeman]

I'm more interested in the experience manual owners have with the system as I have found that my 2008 e-HDI stops below 20 kph but fails to restart if you don't come to a complete stop such as still creeping up to a line of vehicles or in anticipation of a gap in the roundabout traffic.

A 'bong' and a message is no substitute for basic safety in the pursuit of 1-2 grams of CO2.

[Ryeman]

Is coasting not automatically activated when you go round in "ECO" mode?

It is on my Diesel DSG and was the same on my Petrol Golf R DSG, too.

Or are you not able to select different modes?

You have to remember to turn it off every time you get in and start the car.

[willl]

Is coasting not automatically activated when you go round in "ECO" mode?

It is on my Diesel DSG and was the same on my Petrol Golf R DSG, too.

Or are you not able to select different modes?

There's no ECO mode on my petrol DSG Yeti, but yes, it's automatically activated when you take your foot off the accelator. You can turn it off via the maxidot.

From what I gather, it's a relatively new feature on petrol Yeti models. Possibly from MY16 and onwards.

[Ootohere]

What is the 1.4TSI in your Yeti.  is it a  92Kw / 125 ps Turbo Petrol engine without ACT.  

Do you know the engine code?