Coasting in neutral

[Suntory1980]

I have the habit to put my MT intok neutral and let it roll to the next "red" traffic light, i notice no charge of the IMA will happen until i shift back in gears.

My question is:am I losing/wasting useful energy to charge my battery? Or is neutral coasting a good thing to do?

[Willie Williford]

Bad idea, you definately are not useing the REGEN mode to it's maximum.
Another thread about the same topic that eventually got very heated.

Willie

[Eli]

This will depend entirely on who you ask. FWIW, it is against the law to coast in neutral in many states. I was taught to always be in the proper gear for your speed. This includes staying in 1st while stopped at a light. It took me some time to get used to switching to neutral while stopped at a light.

You are wasting energy by coasting in neutral. Maximizing the use of regenerative braking will always be the most efficient. Also, if your engine is not in auto-stop while you are coasting, you are wasting fuel idling.

Insight #1 is on the original brake pads at 160,000 miles. Avoid the use of your friction brakes like the plague, IMO. That's wasted energy.

[Eli]

Not surprising that threads on this subject get heated, they always do. People need to learn that their way may not be the best way, myself included. People have very specific driving habits that they seem to cling on to for some reason. It just depends on how you're taught.

Many people leave the car in 5th gear to stop, or even worse - immediately shift to neutral for the entire stop. That is improper manual transmission driving technique, IMO - for any car - and especially for the Insight. Downshifting is the only way to maximize regenerative braking.

Once again this leads into my desire to video tape every aspect of my driving that I can. It would be really neat to both show others how I drive, and have others critique it. I'm certainly open to suggestions, but I think it could help newbies, and especially newbies to manual transmissions, learn some of the concepts.

[racer26]

Yup. Coasting in neutral = bad in the insight. You're wasting energy in two ways. 1) by not regen-ing when you can, and 2) by forcing the engine to use gas to idle while you coast. By decelerating in gear, you engage the engine's Deceleration Fuel Cut-Off mode, where the fuel injectors are shut off and the wheels are used to keep the engine turning fast enough to keep things operating properly. Many modern fuel-injected cars have this feature.

FWIW, DFCO is MUCH easier to see when you have your gauges set for metric, as the iFCD (the bargraph) shows 0 L/100km when in DFCO or autostop while still moving, 12 L/100km when stopped (even in autostop, which IMO is wrong. Stopped in autostop, I'm using 0L/100km too.) and your actual usage the rest of the time.

With the gauges set for MPG, you see 0 MPG when stopped (regardless of autostop status like the 12L/100km in metric), 150 MPG when in DFCO, autostop while still moving, when you're legitimately using fuel, but at a rate > 150MPG, and then you see your actual usage when the graph is capable of resolving it (0-150MPG)

[AbCaRed00]

I've coasted on occasion out of gear but don't any more after getting my scanguage which shows the fuel measurements down to a couple of digits. A close look at the FCD bar, [though not a good idea when coming to a stop ahead in traffic I'd say], will show similar.
My experience in the Insight when coasting in neutral is that the fuel shut off doesn't happen gliding down in speed.
i.e. With in-gear coasting, I see fuel consumption go to 0.00 LPH [litres per hundred km] this equals fuel cut-off. In neutral coasting out of gear or with just the clutch pushed in, I typically see around 0.50 LPH which means the fuel injectors are passing fuel.
Usually I see a Lean Burn '0' value coasting down in gear. Usually when idling to a stop I noticed that the OX2 reading on the scangauge, [a.k.a LBN =lean burn] it is elevated around 80 except on the very hottest days.
Another reason for not coasting to a stop is not only may there not be enough vacuum for the brakes to work optimally which could be a safety factor in extremes, but also from point of economy low vacuum level may delay the autostop feature from kicking in and waste more fuel.
The way i operate my insight is to coast in gear, try not to have to use the brakes if I can maintain momentum, hold the brake pedal down a couple of mm to activate the regen and slow down, using more brake force as necessary, and when the green regen bars disappear around 32kph [20mph] go all in with the clutch to the floor, pull it out of gear in neutral and go into autostop, release the clutch and keep the brake foot on just the mm or two required to keep in autostop. Once under a certain speed [say 6kph] I can release the brake and coast to a gentle stop; releasing the brake at a somewhat higher speed will start the engine again.
Safety's number one, of course, but for me the thing that cinches not coasting at speed in neutral aside from the regen lost, is lacking the fuel cutoff seen when coasting in gear.

[timny1984]

I tend to keep the clutch pushed in all the time (when i'm not in gear of course). i never release the clutch when moving (in neutral), and even at lights i keep it pushed... never was taught to drive manual, I just knew how mechanically it works and taught myself. If you keep the clutch in you can release the brake and the engine will stay off if you are out of gear under 20mph fyi. i have a few spots where i can be in auto stop and get up to 30 or 40mph engine still off, gotta love it when that happens

yes regen/energy is lost coasting, but this whole week i have been at 19-20 bars on the soc. a few times i can't regen because the battery is "full" and that's annoying as anything when you are going 55mph and hit a yellow light. you just know all that energy is going right into heating those rotors... and i like my rotors cold, haha. I need MIMA to use all this energy better.

Tim

[Willie Williford]

If you pay close attention you will see the rpm of the engine above 1200 rpm when coasting down in neutral from about 65-70 mph. (Possible silent charge?) Even with the clutch pedal "pushed down" in the same scenerio the rpm will still be above 1K....try it.

HTH
Willie

[AbCaRed00]

Originally Posted by timny1984

I tend to keep the clutch pushed in all the time (when i'm not in gear of course). i never release the clutch when moving (in neutral), and even at lights i keep it pushed... never was taught to drive manual, I just knew how mechanically it works and taught myself.

The only thing about that is the throw-out bearing on the manual transmission will be under load for a whole lot more time.
My bias against lots of clutch use is from operating large trucks and industry training, so may not apply directly to smaller vehicles, though [generally] I still follow the axioms.

[Eli]

Yeah, that's the only concern with keeping the clutch pushed in. The Insight's throw out bearing seems to be very robust though, it should last the life of the clutch even if abused.

I saw a post on a message board recently about a Kia throwout bearing that disentigrated with only 80k miles on the car. It was made out of plastic!

The engineer that thought a plastic TOB would be a good idea should be executed. That's how they handle those things over there, right?