Kia Coasting Neutral Control

[Swervin_Mervin]

"The 2019 Kia Stinger offers Coasting Neutral Control. This advanced feature automatically shifts the 2019 Stinger's transmission into neutral when coasting, which optimizes fuel efficiency. This further improves the Kia Stinger's already impressive fuel economy without compromising performance. Coasting Neutral Control is standard on the Premium, GT1 and GT2 trims of the 2019 Kia Stinger."

Eh? I thought cars had, for years now, cut fuel entirely when not under load. So how can this be a better way of doing things as surely it means fuel is needed to keep it idling?

Obviously I must be missing something but I can't see what.

[Nathan]

I thought coasting in neutral was less efficient than coasting in gear

[NotoriousREV]

Same. Eco mode on my Golf did this and I always thought it was weird.

[Jobbo]

Loads of cars do it - anything with a many-gear auto box has had the ability to coast for some years. Not sure if it was introduced by ZF first but it's not unique to them anyway.

ETA: the 3-series has done it since at least 2014.

[Richard]

I thought that keeping the car in gear was better, because it kept the engine turning over without needing fuel? Did Clarkson tell me that? Maybe when he drove an A8 to Edinburgh and back?

I guess maybe newer engines don’t need to be kept turning over like that anymore?

[mik]

injecting a sniff of fuel to keep it idling must be more efficient than no-fuel + engine-braking.

I assume they confirmed this before installing this feature

[Jobbo]

injecting a sniff of fuel to keep it idling must be more efficient than no-fuel + engine-braking.

I assume they confirmed this before installing this feature

I'm not sure they'd bother checking that first. They probably just went to the effort of engineering it in, getting type approval etc without really knowing and just in the hope it would be a selling point.

[Swervin_Mervin]

"The 2019 Kia Stinger offers Coasting Neutral Control. This advanced feature automatically shifts the 2019 Stinger's transmission into neutral when coasting, which optimizes fuel efficiency. This further improves the Kia Stinger's already impressive fuel economy without compromising performance. Coasting Neutral Control is standard on the Premium, GT1 and GT2 trims of the 2019 Kia Stinger."

Eh? I thought cars had, for years now, cut fuel entirely when not under load. So how can this be a better way of doing things as surely it means fuel is needed to keep it idling?

Obviously I must be missing something but I can't see what.

:belm:

[Jobbo]

Is your google broken, Mike?

https://www.autocar.co.uk/opinion/green ... rough-life

[Swervin_Mervin]

Is your google broken, Mike?

https://www.autocar.co.uk/opinion/green ... rough-life

Perfect ta

I was rushing out of the office at the time so posted in the knowledge that some kind soul would provide a link/clarification

[Swervin_Mervin]

Has got me wondering now though. I haven't noticed anything like this on the Superb or the 125i before it - I'd have expected to notice it coasting more freely off-load, and revs dropping/picking back up again.

[Jobbo]

I bet the Superb will do it - not sure if it was introduced part way through the life of the 1-series. I've tried it on my A6 but only once; it only functioned in Eco mode.

[Swervin_Mervin]

Ah yes - eco mode. No wonder I won't have seen it then. Lasted about 5s on the 125i before cancelling never to be re-engaged again. And yet to be engaged at all on the Superb

We've got a decent run to do in a couple of weeks so might try it out.

[Simon]

My Merc does this in Eco mode.

IF you're braking to a stop then it's more efficient to leave it in gear with no fuel being injected.

IF you're coasting at a steady speed it's more efficient to put it in neutral as the fuel used to keep the engine at idle is less than the wasted energy in leaving the car in gear and the car losing speed through drag in turning the engine over.

/Thread.

[Jobbo]

IF you're braking to a stop then it's more efficient to leave it in gear with no fuel being injected.

I bet Merc wish they'd thought of that before foisting it upon you.

[Orange Cola]

The next step is coasting with the engine off. Mild hybridisation has a fair way to go yet!

[Simon]

IF you're braking to a stop then it's more efficient to leave it in gear with no fuel being injected.

I bet Merc wish they'd thought of that before foisting it upon you.

When my car does it I can disable coast with a flick of the left paddle. Best of both worlds innit.

Then again, I don't use Eco much as the throttle mapping is just too spongey.

[Jobbo]

The next step is coasting with the engine off. Mild hybridisation has a fair way to go yet!

Didn’t people say it used more energy restarting an engine than keeping it running? Same sort of fallacy as the overrun fuel cut-off which led to this thread.

[mik]

The next step is coasting with the engine off.

And your eyes closed. A la Seb.

[Orange Cola]

The next step is coasting with the engine off. Mild hybridisation has a fair way to go yet!

Didn’t people say it used more energy restarting an engine than keeping it running? Same sort of fallacy as the overrun fuel cut-off which led to this thread.

It depends on the system being used, but it’s basically stop/start at higher speed with an electric clutch and some of the forwards momentum can be used to restart the engine. The best benefit comes from lifting off and coasting to a much lower speed with the engine off, any brake input is bolstered by resistance from charging the 48v system.

The overall on test returns appear to be minimal, in the region of 0.x-1.x grams per kilometre for the gearbox and engine switch off alone. Add in additional energy recovery from the braking system, electric powered ancillaries running off the 48v system, lower rolling resistance tyres, better wheel bearings, slightly lighter vehicles and you can see 2, 3, 4 grams per kilometre in a single update. It all adds up and counts towards the amount of ‘emissions credits’ an OEM can claim and therefore what cars can or can’t be sold in a given market.