coasting more efficient than regen: Audi
 

http://ecomodder.com/forum/attachmen...1&d=1405082593

Audi is producing a plug-in hybrid with a ~50 km / ~30 mile electric range which reverts to "normal" hybrid mode when the charge is depleted.

The most interesting thing I read in a review of the car was this (Neil will like this bit):

Very cool. Of course, this freaks people out who want what they're used to:

However, in true German style, they offer a nice solution via the paddle shifters. You can get regen if you want/need it without also activating the friction brakes:

Source: Car Review: 2015 Audi A3 Sportback e-tron | Driving

Regen is nice but especially for me- not much stop-n-go- coasting is far more efficient.

That depends. For me, most coasting involves descending miles of 6% or greater grades, so without regen (or engine braking) I'd soon be travelling faster than reasonable - to say nothing of speed limits. So much more efficient to put the energy back in the battery via regen, than have it wasted as heat from the brakes.

Fortunately I have a MIMA system, which like the Audi's paddle shifter, allows me to invoke regen whenever I want.

If I remember right, the VW XL1 does the same thing--no regen unless the brake pedal is depressed. It would be nice for this feature to go mainstream.

Again, having owned an insight and felt it out its a conclusion many come to. The least you use of the ima system the better your mpg is. :eek:

To cancel the auto braking regen of the gen 2 you just need to put light pressure on the throttle. To get more regen braking press the brake petal enough to turn on the brake lights. For more, click the left paddle while holding the brake petal.

I am glad they didn't completely pull regen out. It really is invaluable sometimes- at some point we all need to slow down/come to a stop, and it just kills me to turn it into wasted heat.

Really depends on the sort of driving you do. If there are sizeable hills, it really helps. From my own recent experience (having the IMA essentially not working for a few months due to an unbalanced battery pack), it's worth at least 5 mpg from not having to downshift as much during climbs.

Interesting, my assumption was the savings was from the lack of alternator and the higher voltage from the ima rotor converter to 12 volts was more efficient for the charging system. Even if the regen meter doesnt register, it does 7 amps at a bare min.

I love it... excessive regen braking in some hybrids is kind of irksome... you want to minimize momentum loss rather than wasting doing regen. And if you really want the regen, a light touch of the brakes on most of these systems activates the electric regen braking rather than the mechanical brakes, so you still get it when you want it.

One of my biggest complaints of my Prius vs the '06 Escape Hybrid we had before it is the regen on lifting off the gas. In the Prius, I have to give it just a little throttle to keep the regen away, the Escape coasted without throttle unless you put it in L "gear".
Its nice to know that manufacturers are actually looking at what works better.

The same is true of the Insight, BUT if you have a ScanGauge or similar, you might discover that the 'little throttle' is not actually sending gas to the engine, it's just cancelling the regen. At least that's the way the Insight works, and it would seem like an obvious thing to do in order to provide a driving experience that's 'just like a normal car'.

VW will have this free wheel coasting on the eGolf, and there you get some/more regen by bumping the shift lever. The Smart ED also has paddle selected regen with free wheel coasting as a $200 option. And the Fit EV does this in Eco mode, as well.

Some EV makers "get it"! I'm sure it would take getting used to, and you do have to learn how far your car coasts to take full advantage of it, but at least there is no learning required to *get* free wheel coasting! Just lift your right foot ...

What is old is new again.

Freewheeling circa 1931.

1931 and 1932 Plymouth PA cars

regards
Mech

After reading this and a couple links, I find I like it. I assume no modern ICE car has this? Excellent technology for the early 30's. :thumbup:

In one of the few cases where a vehicle capability is made illegal, Virginia outlawed the use of freewheeling after accidents where brakes failed coming down the US routes that go over the appalachian mountains. US 50 and US 33 are two of the routes and I can tell you from firsthand experience that they can get pretty hairy in a new car, much less non power assisted 4 wheel drum brakes where the fluid could reach boiling point. It is my understanding that the freewheeling could not be disengaged while the car was moving.

The hilarious thing is I don't think the law was ever repealed, so technically a Prius is illegal to operate on those same roads, by the strictest interpretation of the law, which will never happen.

regards
Mech

NEUTRAL in a Prius CVT is STILL actually mechanically gear-engaged, because two of the three shafts are turning in opposite directions at exactly the same speed, but ALL the gears are always meshed.

And Neutral in the Insight is actually Neutral, with the engine ticking over at Idle where it would DFCO if it were left in D.
So it will actually use more fuel in Neutral then when carefully matched with the throttle to defeat regen. Or given a little more throttle to prolong the glide under mild electric assistance, or deliberately left unthrottled to get regen while mildly braking to prevent overshooting the destination. There is some flexibility in that range to play with.

I like the regen though because it will use the power to accelerate again, and you don't want it to regen while maintaining speed after acceleration to replenish the battery while you could have gotten that charge from deceleration.

Also, the Insight is a keen roller. I generally need to decelerate harder than just coasting when leaving the highway etc. The deceleration under mild regen is about the same as the other cars do when they just lift the throttle, or maybe just a fraction more.
The point is, I can roll along with the other traffic leaving the highway without having to touch the brake pedal, if they don't brake too.
I dislike having to light the brake lights when just losing speed at the same rate as the other cars when they don't brake. So I am happy with the mild regen.

IIRC the Tesla model S can be driven with just the accelerator pedal under normal conditions as it will regenerate strongly when you lift off completely. I wonder if that makes the brake lights burn?

Define "modern"
 

Voila:
http://bringatrailer.com/wp-content/...73-SAAB-96.jpg

Here's a view of the little freewheel unit clearly visible along with the attached diff:
http://www.vintagesaab.com/images/freewheel.jpg

The humble and mighty SAAB 96 bore a freewheel throughout its production run, right up to 1980, even though the original reason for its inclusion, the old two-stroke three-cylinder that needed not to overrun its fuel-oil mix during closed-throttle deceleration, had been out of production for over a decade.

The freewheel could be a service hassle. Some owners fitted springs under the handles of theirs, to hold them in a locked position. Some - namely, Dad - tied a length of twine from the handle to the handbrake pivot. Whatever it takes.

Just one fine example of another hapless SAAB owner:
http://img339.imageshack.us/img339/7...wheellever.jpg

In the 1st-gen Insight, there's some computer logic that determines whether or not to regen when your foot is off the gas, and I think it mostly has to do with battery level. In city driving it likes to be at around half charge, and will cut off deceleration regen above that, but get up to highway speeds and it will take the meter to full. It's a slug to drive without assist so I'm rather glad that just it's able to stay topped off with only decel regen.

More coasting news from Audi:

They've dropped the CVT in favour of a new 7-speed DSG with a "coasting function" in a revised ICE-powered A6 high efficiency model.

Facelifted Audi A6 to include new 109g/km ultra model | Fleet World

We have had these DSG's VAG cars with the freewheel function for a few years, available on the 170bhp diesels across VW, Skoda, Audi you can turn it off in the menu.

My Lupo 3L does it too :)

I wonder if the European general public finds freewheeling as objectionable as the American public seems to find stop/start.

Some of the American public still seems to hold freewheeling in utter contempt... at least from what I've seen in some online discussions.

And I've even seen articles from Popular Mechanics used as argument. Somebody should tell the manufacturers they're doing it wrong!

It always seems like everyone else wants to maintain 10 MPH over the speed limit on the freeway until they need to break. I may make the light. I may not. I coast in neutral and see what happens. I usually cannot turn right on red, so I do not worry about it.

Can you PM me some links or more info about this my girl has a 09 jetta that loves to coast in neutral.

Thirty years ago, when I got my learner permit under the German driver's testing class we drove a VW Golf-E automatic with coasting feature when you let off of the throttle. It was awkward for a short time and shortly became 2nd nature.