Mazda exec says EPA testing is reason company doesn't have Stop/Start feature in U.S.

[redpoint5]

Originally Posted by UltArc

the FE.gov calls BS on certain results. All of my tanks over ~37mpg come with a question mark and say it's too high of mpg- they calculate my LMPG as ~32 ish for public view, while the regular view for me (loaded with question marks lol) is >34.

And at the same time, the numbers are skewed. I find often when I talk about mods (explain why my car looks goofy, or am excited from a fill up), others don't even KNOW what their MPG is, they either have a guess, "it is usually like 30 bucks," or every so often they look at a standard issue gauge that has never been reset or checked. My point is, until our cars record out mileage and send it somewhere, real world results won't get it*. This point is also that the mileage that is reported isn't done by the majority or people who don't really care (60-90%?).

I realize there is a selection bias that likely skews the self-reported fuel economy average on fueleconomy.gov, but I don't think it's fair to submit your fuel economy when it includes mods that improve the number. There isn't a way to convey to users of fueleconomy.gov that you achieved the results partially by modding your vehicle. It does a disservice to those attempting to compare the vehicle to other models.

While I do employ efficient driving techniques and contribute my MPG to the fueleconomy.gov database, I don't include the improvements that various mods have allowed me. After all, I could simply convert a '76 Eldorado V8 into an electric and claim 100mpg.

[UltArc]

Originally Posted by redpoint5

I realize there is a selection bias that likely skews the self-reported fuel economy average on fueleconomy.gov, but I don't think it's fair to submit your fuel economy when it includes mods that improve the number. There isn't a way to convey to users of fueleconomy.gov that you achieved the results partially by modding your vehicle. It does a disservice to those attempting to compare the vehicle to other models.

While I do employ efficient driving techniques and contribute my MPG to the fueleconomy.gov database, I don't include the improvements that various mods have allowed me. After all, I could simply convert a '76 Eldorado V8 into an electric and claim 100mpg.

That's a fair point. I wish I could upload images and details, but I see what you're saying. It's the same way I feel when I see impressive fuel images here, and find they have one tank they went 10 miles EOCing downhill...lol

I do think that an engine swap or taking a driveline and building everything else different is enough to classify it as something else, but that's kind of like someone putting a supercharger and full bolt ons and internals to their v6, it's not an accurate representation of what a normal user can expect. Heck, a kill switch alone gives great results.

[baldlobo]

fiat/chrysler introduced stop/starts systems on certian models for 2009. the 300/charger, 2mpg city jump from the previous year.

Compare Side-by-Side

whoops; i might be wrong. but they did introduce something in 2009

http://www.allpar.com/corporate/tech-2009.html

[t vago]

I'd love to be able to add some sort of auto stop/start feature on the Karen-mobile. Maybe something like a shifter momentary button that keeps the engine turned off when I push it, and the brake pedal is applied, and the vehicle is stopped.

[cptsideways]

In the UK all the Skyactiv cars have stop "except the base model SE" which no-one buys!

By default the system is ON everytime you turn the ignition on & there is a button to turn it off, it works really well on the auto's & the manual the start signal comes off dipping the clutch pedal. Its pretty neat & works well.

[euromodder]

Originally Posted by niky

What I think is clever with Mazda's system is the way it stops the engine with a single cylinder primed to fire. The restarts are eerily seamless for a car without a hybrid assist/starter motor. If all motors could do that, imagine how much we'd save from not having to "crank" the motor in the morning!

It's clever, but it wouldn't last overnight as the engine cools off.

My car also re-starts rather easily, and within the time it takes to get the clutch pedal to the floor, but that's probably due to it being only 1L

Still... short stints in traffic... thirty minutes or so (assuming you have a clear run to charge up before you get stuck), the difference is big.

The max. charge is always limited to what the battery will hold.
Even without AC or radio on, it's still limited to what the manufacturer put in as excess battery capacity - which is also costing mileage (weight, recharging).
A few stop/starts too soon after one another, and the engine stays on as the battery's reserve capacity gets too low.

When coasting down, it's not using regenerative braking either.

If you're sitting in gridlock from the time you turn the engine on till the time you park, not so much.

Stop/start is rather tedious in that kind of situation.
By the time it shuts down , it often has to restart again .
One'd be better off trying to keep rolling, even coasting engine on.

[niky]

Originally Posted by euromodder

It's clever, but it wouldn't last overnight as the engine cools off.

Oh, definitely not. The capacitor charge won't even last within the day.

Originally Posted by euromodder

My car also re-starts rather easily, and within the time it takes to get the clutch pedal to the floor, but that's probably due to it being only 1L

The difference here is SkyActiv doesn't put much stress on the starter or battery due to the way it "primes" itself to fire. How much stress is avoided, however, is not known.

Originally Posted by euromodder

The max. charge is always limited to what the battery will hold.
Even without AC or radio on, it's still limited to what the manufacturer put in as excess battery capacity - which is also costing mileage (weight, recharging).
A few stop/starts too soon after one another, and the engine stays on as the battery's reserve capacity gets too low.

When coasting down, it's not using regenerative braking either.

Mazda doesn't use a big battery pack. It's funny, actually, that it seems to have more stored up "stop time" than the CR-Z in similar conditions. The CR-Z has a battery pack taking up two-thirds of the otherwise humongous GE chassis rear cargo box.

The Mazda6, on the other hand, claims a lighter curb weight than its competitors, and if the capacitors take up any trunk space, it's hard to see where. Whereas with something like an Optima hybrid, you've got a lot of chunky hardware eating into the trunk.

Originally Posted by euromodder

Stop/start is rather tedious in that kind of situation.
By the time it shuts down , it often has to restart again .
One'd be better off trying to keep rolling, even coasting engine on.

There's a deactivation switch, but after trying it both ways, I left i-stop on. Didn't mind the shutdown... and it seemed to do more good than harm (as per the onboards... testing it out full-tank to full-tank would have taken more days than I had with the car). Simply applying less pressure on the brakes kept it from going off at stops I thought would be too short.

[gone-ot]

Originally Posted by niky

There's a deactivation switch, but after trying it both ways, I left i-stop on. Didn't mind the shutdown... and it seemed to do more good than harm (as per the onboards... testing it out full-tank to full-tank would have taken more days than I had with the car). Simply applying less pressure on the brakes kept it from going off at stops I thought would be too short.

Does the Mazda Owners Manual mention anything about an operational "time duration limit" on their engine stop, such as you found by "...simply applying less pressure on the brakes..."?

[niky]

The engine stop only goes on if your steering wheel is reasonably straight (won't go on if you're turned slightly at the bottom of a parking ramp or in a parking lot) and if you press the brake pedal past the "detent" that tells the car you want full braking power.

As for time limits, no set limit specified in the manual that I saw. (I only had the car a week, and I pored over the manual only twice, looking for more info on the system).

[gone-ot]

Oops, I did not word my "time duration limit" question well.

Rather, I should have asked "time duration delay" as in does the STOP function activate immediately upon vehicle movement stopping, or is there a slight perceptable delay between when the vehicle stops and when the engine stops?