By on August 15, 2011

Among the many new SKYACTIV technologies that Mazda plans on introducing to its global lineup, a unique start-stop system is one of the most important. Initially Mazda had decided not to bring its idle-stop system to the US as the EPA system didn’t measure a major improvement in efficiency, but ultimately the decision was made to make all of its vehicles idle-free by 2015. But an early test of a SKYACTIV idle-stop-equipped Mazda2 by Automotive News [sub]‘s Hans Greimel reveals an interesting characteristic:

a funny thing happened when I paused for a red in Tokyo’s harbor district.

After a few moments of silence, the engine clicked on, as designed, to help keep the air conditioner going. OK, that’s normal. But as the engine jumped to life, so did the steering wheel. To my surprise, I found the engine’s start-up vibrations turning the wheel to-and-fro in my loose grip.

I turned to the Mazda powertrain engineer sitting beside me.

“Didn’t engineers notice that during development?”

“Yes.”

“Well, didn’t they try to fix it?”

“Yes, but they decided this amount of feedback was acceptable.”

I’ve driven cars with stop-start engines before, but this was a first. The self-animated steering wheel only happened once during my 40-minute run. And it was more an unexpected annoyance than a safety issue. But I suspect it will take drivers some getting used to.

Greimel says the SKYACTIV Mazda2 1.3 won’t be sold in the US, but the same technology will arrive with the next Mazda3. Because Mazda’s idle-stop system uses detonation rather than an electric motor for re-start, it eliminates a key problem with early stop-start systems: battery wear-down. But apparently Mazda’s detonation-based system isn’t without its downsides. Here’s hoping they work out the kinks before bringing the system to the mass market.

Read more: http://www.autonews.com/article/20110804/BLOG06/110809893/1499&SectionCat=product#ixzz1V8ErV7kY

Get the latest TTAC e-Newsletter!

36 Comments on “Mazda: Breaking New Ground In Torque Steer?...”


  • avatar
    segfault

    Sounds like a brutal reminder that you’re driving a small car… The trend has been to try to make smaller cars as smooth and quiet as larger ones.

  • avatar
    Volt 230

    You know what? for the few pennies of gas this is gonna save, I’d rather do without the mechanical complexity and the long term reliability and repairs issues. Its like “don’t pay me now, just pay me later.”

    • 0 avatar
      PintoFan

      Stop-start has the potential to save a lot more than a “few pennies” of gas. As for the whole “mechanical complexity” argument, just get over it. Cars of today are infinitely more complex than they were 30-40 years ago and yet they are far more reliable.

      • 0 avatar
        Sinistermisterman

        Just talk to any modern Mercedes owner…

      • 0 avatar
        OldandSlow

        It’s all well to boost MPG a mile or two, but I want to see how satisfactory the “start/stop” feature is going to work in freezing weather, with the lights and HVAC running continuously. Like wise, summer rush hour traffic in the South is going to be a challenge without A/C.

      • 0 avatar
        redav

        Idle stop does in fact improve city mpg by around 10%.

        Also, as stated in the article, if the engine needs to be on, e.g., it isn’t fully up to temperature, high accessory demand, then the engine doesn’t shut off. So, in those cases, the engine is the same as what exists presently.

      • 0 avatar
        Volt 230

        That is why most techs I talk to don’t like the “new” stuff, too over complicated and trouble-prone. Even the simplistic Yaris is gonna become a nightmare when they put in this stop/start crap this upcoming model year.

  • avatar
    skor

    You wanna talk torque steer? Ever drive a first gen Ford Probe GT, the one with the turbo 4? That was also a Mazda product rebadged as a Ford. Under hard acceleration, when the turbo kicked in, it was like an unguided missile.

  • avatar
    CJinSD

    If anyone is serious about reducing the fuel wasted by idling, their first action should be removing all traffic calming strategies from our roads. Time lights so traffic moves. Give higher traffic roads the right-of-way at intersections. Remove 4-way stops. Add lanes. Eliminate roundabouts in tourist areas. Build bypasses. Make travel by car more efficient instead of trying to herd people into less efficient means of transportation.

    • 0 avatar
      PintoFan

      As much as I agree with your sentiments, what you’re for is going to be much harder to accomplish than the gradual phase-in of a relatively simple technology on new cars. The structure of our roads is already established, and what’s worse, their administration isn’t centrally controlled in the same way that new vehicles are. The current road network is the result of years of patchwork construction and haphazard design. Add to that the very real need to reduce congestion in urban areas and you see why it is easier to regulate new vehicle features than it is to completely redesign our road network.

    • 0 avatar

      Umm, they’ve been trying everything you have stated for the last 50 years in North America…that hasn’t really done the trick. I know, I know…we’ve been dealing with significant increases in traffic density, but the reality is simply that cars are going to idle, despite our best efforts. I’m up for new strategies like this.

      As for “less efficient means of transportation”…the car is THE least efficient means of transportation we have, in terms of fuel and resource consumption, and quite often in terms of time. So I’m not sure what other form of transportation you are referring to.

      • 0 avatar

        As for “less efficient means of transportation”…the car is THE least efficient means of transportation we have, in terms of fuel and resource consumption, and quite often in terms of time. So I’m not sure what other form of transportation you are referring to.

        It depends on the number of passengers. When you consider that buses run mostly empty at night, I’d be surprised if a transit bus company’s overall fuel efficiency per passenger mile is much higher than a commuting car. Buses can be efficient because they can carry a lot of people, but they are seriously underutilized much of the time. When a bus that gets 6mpg has only three passengers, a car that gets 20mpg in the city will be more efficient per passenger mile. 20 miles at 6mpg is 3.33 gallons of fuel which works out to 18 passenger miles per gallon if there are 3 people on the bus.

        And in terms of time, a car lets me travel on my own schedule, which has a value all its own. I can get downtown in 20 minutes if it’s not rush hour. If it is rush hour, I can take Woodward instead of the freeway and it might take me 30 minutes. I can leave when I want to and go home when I want to. If I get busy while I’m downtown, I don’t have to worry about decreased bus service at night. To take public transit I have to walk 10 minutes to the bus stop. Wait for the bus to take me to a transit depot. Wait for the downtown bus there and if I’m lucky that the next bus is an “express” bus, that means it’s going to take another 45 min to get downtown. If it’s not an express bus, make that an hour, at least.

  • avatar
    Demetri

    Just to clarify, idle-stop is not going to be on the 2012 Mazda3 with the Sky engine; not in the US at least. When they say the next Mazda3, they mean the next-gen model, in MY 2014 or 2015.

    • 0 avatar
      redav

      I’m anticipating the next Mazda3 to be in the 2014 model year. Perhaps it is my wishful thinking, but it seems Mazda acknowledges that the smiley face is a dud, and I believe they are eager to get the full benefit of Skyactiv into their most important vehicle.

      If so, I am very happy since I would love to pick up a compact hatch with the full SkyActiv suite and design per the Minagi concept, and I don’t want to wait more than a couple years.

  • avatar
    mpresley

    Damn. Where is technology when you need it? If only Saab had of thought of this, it could have all played out differently for them. That, plus if they’d only have added a goofy grin to the front of the 9-3, they’d have had a million and two seller on their hands.

  • avatar
    Twin Cam Turdo

    I think you’ve missed the point about battery discharge.

    The majority of battery discharge during a stop/start cycle is from electrical accessories, not the operation of the starter motor.

    From this point of view, the non-use of the starter motor for engine restarting is insignificant.

  • avatar
    SecretAznMan

    There’s some pretty flimsy info flying around here. I don’t think SkyActiv necessarily includes start/stop. At least I hope so, otherwise, the Mazda2 is pretty screwed. It has to get better fuel economy. Also, did anyone notice how there are five links littered through the article, but when it comes to the actual article link, it’s a cut and paste? Maybe because the entire source was quoted.

    • 0 avatar
      M 1

      I believe the non-clickable link is because the article is subscription-only (hence the “[sub]” note in the article).

    • 0 avatar
      Demetri

      SkyActiv doesn’t necessarily include anything. It’s all being added piece by piece, and if stop-start doesn’t work out, they can simply remove it. The 2012 Mazda3 won’t have it.

      Actually, the 2012 Mazda 3 isn’t even getting the optimal version of the engine either; they weren’t able to fit the new exhaust manifold within the confines of the current chassis, so they had to actually lower the compression of the engine for this incarnation. The next gen 3 will be designed around it, so it will be higher compression, increasing fuel economy and power.

      • 0 avatar
        stuntmonkey

        In many respects, Sky-active is really a fancy marketing term for “Kaizen”, which is more or less how things have been done all along. Somebody in marketing had the wherewithal to gather all of the future R&D together into one umbrella campaign.

  • avatar
    Robert.Walter

    This sounds like a very bizare phenomenon.

    At first, I was thinking that the motor has kind of a shaky start, and it was sending pulses from the p/s pump out into the hydraulic lines, but IIRC, the M2 has column PAS, an electric system, hence no pump, no lines, no wave propagation down the lines to unbalance the gear…

    Torque steer is more or less a function of unequal length front prop-shafts. But length plays no role if the tires are not rotating as is likely to be the case at an stop-idle-start situation.

    If it is a colPAS system, then maybe there is some transient signal that is coming into the PAS-ECU and making it shakey…

    Would be interesting to know what the technical issue is here… I’ve never heard of such a thing before, except for when there were development attempts to simulate sensor problems and self-steering worst-case conditions (in such cases, the system can be excited so that the wheel cranks back-and-forth so quickly, it will be ripped out of your hands…)

    • 0 avatar
      OldandSlow

      A second problem, will the engine maintain an optimal operating temperature during a cold winter morning’s commute in the inner city?

      Will the engine reach its optimal operating temperature later than without the “technology” during a cold morning commute?

      • 0 avatar
        golden2husky

        I would assume the engine would be programmed like a hybrid. The engine comes up to operational temperatures in cold weather before it begins to cycle. And it is never allowed to cool down below a certain point.

  • avatar
    johnny ro

    I remember a review of an antique Rolls Royce, written maybe ten years ago, of an early 1900′s example. They said that 1/4 of the time, just turning on the ignition (not the starter) would result in a silent commencement of engine running. Gas waiting for a spark in a cylinder with a still piston.

    • 0 avatar
      mfgreen40

      I have done this with my Model T Ford. The spark advance lever and the buzz box coils make it doable. The best (story) I have heard is the guy would turn the key on his T get out and kick the tire, the jolt would cause the spark lever to move down and send the spark to a cyl. that was in the proper position and the engine would start.

  • avatar
    niky

    Sounds more like the electric steering pump priming than torque steer. If I recall correctly, Mazda uses a hydraulic rack wtih an electric pump, so if the pump suddenly turns on, it’s possible the rack will react, much as hydraulic racks on some cheap cars tend to pulse if the wheel is slightly off-center at idle.

    • 0 avatar
      Robert.Walter

      This is what first crossed my mind, until I read it was a M2.

      M2, however, has had column electric eps for nearly 10 years now.

      M3 has a electro-hydraulic unit from TRW, in which an electric motor drives the pump (this is the unit which was recalled due to corrosion in the lines jamming the pump.)

    • 0 avatar
      niky

      Oops. I thought the M2 had the same electrohydraulic unit.

      If not, that is weird. More likely a software glitch than anything else, then.

  • avatar
    MadHungarian

    Does this system avoid using the starter motor entirely for restarting, or not? On the Mazda website, the third diagram toward the bottom of the page is captioned “Combustion + Motor Assist” and the graphics suggest the starter motor is operating. If this works so well, why not eliminate the weight of the starter motor and start the engine this way all the time?

    • 0 avatar
      Brian P

      When the engine is hot, there is little mechanical resistance against the engine spinning over. When the car has been sitting overnight in -30 C, the resistance from the thick, cold oil is certainly more than the cylinder pressure alone can overcome for cold starting.

    • 0 avatar
      Robert.Walter

      Cylinders are not a perfect seal either … even if the engine were maintained at the optimal warm temperature for compression-based starting, the cylinder pressure would vent past the rings and be lost over time… I also assume, but am not sure, that there would be additional incremental leakage over the valve seats too…

  • avatar
    wmba

    The Mazda Global site has had info on this stop-start system for over a year now. It doesn’t rely on compression to start, it depends on the engine stopping at the exact right point, so that a squirt of gas and the air left in the cylinder are ignited by a spark and off she goes. Sounds like it might be a bit of a rocky start if it twitches the steering column, though.

    I wonder how they integrate it, or any stop-start system with an automatic trans, where one has to press the foot brake to use the starter motor. Interesting logic train that will have to be followed to do this automatically. Manual tranny no problem.


Back to TopLeave a Reply

You must be logged in to post a comment.

Subscribe without commenting

Recent Comments

New Car Research

Get a Free Dealer Quote

Staff

  • Contributing Writers

  • Jack Baruth, United States
  • Brendan McAleer, Canada
  • Marcelo De Vasconcellos, Brazil
  • Vojta Dobes, Czech Republic
  • Matthias Gasnier, Australia
  • W. Christian 'Mental' Ward, Abu Dhabi
  • Mark Stevenson, Canada
  • Cameron Aubernon, United States
  • J Emerson, United States