REVscene - Vancouver Automotive Forum

asian_XL · 02-20-2009, 04:00 AM

http://www.mobilemag.com/content/100/354/C16914/

Quote:

If I recall correctly, Mazda said that it currently does not have any ambitions to produce a fully electric vehicle in the near future. That doesn't mean that they're not looking for ways to improve fuel economy and give a nod to Mother Nature though.

At the 2009 Geneva International Motor Show next month, Mazda plans on showing off a version of the Mazda3 with i-stop, an advanced fuel-saving start-stop system. With some hybrids on the market, you'll notice that you can keep the gas engine turned off at lower speeds, letting the electric motor do all the work. The concept is similar with Mazda's i-stop technology, except there does not appear to be an electric motor involved.

The i-stop system, which will also appear in the all-new Mazda3 MPS (which will eventually become the Mazdaspeed3 if the stars align), is designed to completely shut off the gasoline engine when you are sitting at a red light. By doing so, Mazda says that it can achieve 12 percent lower fuel consumption in the city.

The system is designed in such a way that it can start the engine back up in a matter of moments when you need to get up and go again. The zoom-zoom resumes a lot faster than a regular cold start and should not pose any safety hazards as far as we can tell.

The aforementioned Mazda3 MPS takes on the sport hatch configuration and gets powered by the MZR 2.3 DISI Turbo engine.

Black SC2 · 02-20-2009, 06:59 AM

Nothing new. GM has been using a system like this for a couple of years now.

02-20-2009, 07:41 AM

Quote:

Originally Posted by Black SC2

Nothing new. GM has been using a system like this for a couple of years now.

I think the difference here is that the GM uses the electric starter to get the car started, whereas Mazda is using their new vehicle starting procedure. Basically it injects a small amount of fuel in one cylinder, and puts a spark on it. This gets the motor started very efficiently, and is a lot smoother then the electric starter.

I could be wrong, but I know a couple of years ago Mazda was developing it.

Mancini · 02-20-2009, 08:26 AM

My car has a very similar feature. I just need to make a certain twisting motion with my wrist...

zvrkan5 · 02-20-2009, 09:05 AM

bmw had this for a while now...

Great68 · 02-20-2009, 09:25 AM

Quote:

Originally Posted by dustinb

I think the difference here is that the GM uses the electric starter to get the car started, whereas Mazda is using their new vehicle starting procedure. Basically it injects a small amount of fuel in one cylinder, and puts a spark on it. This gets the motor started very efficiently, and is a lot smoother then the electric starter.

I could be wrong, but I know a couple of years ago Mazda was developing it.

That's pretty cool technology. I was going to say, it must be hard on the electric motor starters to be starting the engine so often. Imagine stop and go traffic...

J-Wangsta · 02-20-2009, 09:54 AM

mmm.. so its like hybrid technology?? but not a hybrid car? doesn't it waste more gas when the engine restarts?

InvisibleSoul · 02-20-2009, 10:24 AM

Quote:

Originally Posted by J-Wangsta

mmm.. so its like hybrid technology?? but not a hybrid car? doesn't it waste more gas when the engine restarts?

Haven't you seen the posters that say starting your engine up uses less gas than ten seconds of idling?

qma · 02-20-2009, 11:39 AM

Gas powered golf carts are like this too...

cococly · 02-20-2009, 12:13 PM

Should We try to shut off our engine while waiting at the lights

??

I do that sometimes when it's a big intersection and after I just missed yellow...

godwin · 02-20-2009, 02:10 PM

No they dont have this right now.

Mazda's implementation works on the theory that fuel would combust in chambers that have still have relatively high O2 and compression (valve closed). When the engine is turned off, there are still residual heat. They take the heat into account and use the piezo fuel injectors, to inject just the right amount fuel, so fuel + air will ignite and move the pistons enough to turn the crankshaft so the car will start again.

Obviously this will only work with cars with low internal friction and a light enough crankshaft.. not to mention DI is a given. So right now it is limited to I4 engines... Honda has this feature in one of the idtec engine.

It requires the engine ECU to be high speed and have enough senors (including feedback from Piezo injectors).

Since the latest engines uses electric AC, steering and pumps (fuel, air etc)... you DO NOT use perceptually more gas when stopping and starting.. However not as fuel efficient as atkinson cycled engine used in Hybrids.

Quote:

Originally Posted by zvrkan5

bmw had this for a while now...

Jason00S2000 · 02-20-2009, 02:33 PM

Since I hate nature, when I'm stopped at a light, I floor it and bounce the engine off it's redline.

Sure it uses more gas, but hey, chicks always stare.

you · 02-20-2009, 03:19 PM

Quote:

Originally Posted by cococly

Should We try to shut off our engine while waiting at the lights

??

I do that sometimes when it's a big intersection and after I just missed yellow...

might not be such a good idea because this would increase the wear and tear on ur starter

Alatar · 02-20-2009, 03:32 PM

That's exactly what GM'S BASS does. Shuts the truck's engine off at stoplights. 48V system that makes it into a hybrid, under the "hybrid" guidelines.

The reason just shutting your car off and turning it back on traditionally doesn't work is because of the slow cranking speed of a starter. You only get ~200rpm cranking with the starter. With the BASS and I'm guessing i-stop systems, it cranks the engine at idle speed (800-1000rpm) so you don't need to dump ungodly amounts of fuel through the injectors to get the engine turning.

CanadaGoose · 02-20-2009, 04:27 PM

Quote:

Originally Posted by Jason00S2000

Since I hate nature, when I'm stopped at a light, I floor it and bounce the engine off it's redline.

Sure it uses more gas, but hey, chicks always stare.

hahaha

I wouldn't want this gimmicky system anyways, what if someone was about to hit you and you needed to get out of the way NOW

StylinRed · 02-20-2009, 08:52 PM

Quote:

Originally Posted by E N D L E S S

hahaha

I wouldn't want this gimmicky system anyways, what if someone was about to hit you and you needed to get out of the way NOW

u mean punch it into the middle of traffic ???

Boostaholic · 02-20-2009, 09:24 PM

from the sound of it, they have to stop the crank where one of the 4 cylinder is at the begining of the combustion cycle. I wonder how they do that efficently and effectively.

come to think of it, if the system fails or a sensor goes wrong, everytime u stop the car it'll stall hahaha.

godwin · 02-21-2009, 12:43 AM

Except GM's system has more pumping loss due to the fact the valves have to open and shut to allow fuel in. In Mazda's case because the injectors inject directly inside the chamber, there is no that much loss relatively, so it is more efficient.

The GM system is more akin to the Atkinson cycle vs Otto cycle.

Quote:

Originally Posted by Alatar

That's exactly what GM'S BASS does. Shuts the truck's engine off at stoplights. 48V system that makes it into a hybrid, under the "hybrid" guidelines.

The reason just shutting your car off and turning it back on traditionally doesn't work is because of the slow cranking speed of a starter. You only get ~200rpm cranking with the starter. With the BASS and I'm guessing i-stop systems, it cranks the engine at idle speed (800-1000rpm) so you don't need to dump ungodly amounts of fuel through the injectors to get the engine turning.

- kT · 02-21-2009, 12:48 AM

The mazda's smile at me

CanadaGoose · 02-21-2009, 07:42 PM

Quote:

Originally Posted by StylinRed

u mean punch it into the middle of traffic ???

Make a right turn, change lanes, go up onto the curb...even moving over a few inches more can help emergency vehicle trying to get through

you'll learn what i mean as you gain more driving experience

shenmecar · 02-21-2009, 10:04 PM

sounds interesting actually.

but how does the car know u r at a stop light and not just in stop and go traffic.
i wouldnt want my engine off and on during rush hour, the faggot behind me is gonna honk like hell.

godwin · 02-21-2009, 11:03 PM

Here is a though experiment.

The lowest engine rpm say is 500rpm -> 4500rpm.
A DI injector injects up to 5 times each cycle..

Since the chamber is still hot and primed.. just a squirt is required.

I highly doubt the car at the back will be honking you because your car needed to start up agian.

Quote:

Originally Posted by shenmecar

sounds interesting actually.

but how does the car know u r at a stop light and not just in stop and go traffic.
i wouldnt want my engine off and on during rush hour, the faggot behind me is gonna honk like hell.