The Skyactiv Transmission from Mazda
04-22-11, 09:07 AM
#1
Lexus Champion
Thread Starter
The Skyactiv Transmission from Mazda - Similar to IS-F
From what I am reading, the Skyactiv automatic transmission is offering full range lockup feature. has this been offered by any other manufacturer yet?
Automatic transmissions (AT) can be categorized into three types:
Conventional AT: generates various gear reduction ratios with planetary gear sets CVT: generates various gear reduction ratios with a pair of pulleys Dual Clutch: utilizes 2 separate clutches for odd and even gear sets.
The key requirements for ATs are “good fuel economy”, “quick start-up” (including hill climbing), “direct feel” and “smooth shifting”.The table below shows the drawbacks and advantages of each transmission.
SKYACTIV-DRIVE is the ideal AT with all the advantages of the various types of transmissions:
The torque converter transfers engine power to the transmission through fluid, making a smooth start-up and gearshifts possible. The drawback is that fuel economy worsens due to the loss of power transfer through the fluid, and slippage during rapid acceleration, which causes vehicle speed to lag behind engine speed. Therefore, a torque converter with a lock-up clutch was developed, which locks the torque converter’s turbine to the impeller to improve fuel economy and direct drive feel. To improve fuel economy and direct drive feel pointed as challenges of Step AT shown in Fig.1, the lock-up range has to be maximized. However, in order to do so, we had to ensure NVH performance and clutch reliability.
Automatic transmissions (AT) can be categorized into three types:
Conventional AT: generates various gear reduction ratios with planetary gear sets CVT: generates various gear reduction ratios with a pair of pulleys Dual Clutch: utilizes 2 separate clutches for odd and even gear sets.
The key requirements for ATs are “good fuel economy”, “quick start-up” (including hill climbing), “direct feel” and “smooth shifting”.The table below shows the drawbacks and advantages of each transmission.
SKYACTIV-DRIVE is the ideal AT with all the advantages of the various types of transmissions:
The torque converter transfers engine power to the transmission through fluid, making a smooth start-up and gearshifts possible. The drawback is that fuel economy worsens due to the loss of power transfer through the fluid, and slippage during rapid acceleration, which causes vehicle speed to lag behind engine speed. Therefore, a torque converter with a lock-up clutch was developed, which locks the torque converter’s turbine to the impeller to improve fuel economy and direct drive feel. To improve fuel economy and direct drive feel pointed as challenges of Step AT shown in Fig.1, the lock-up range has to be maximized. However, in order to do so, we had to ensure NVH performance and clutch reliability.
Last edited by chikoo; 05-02-11 at 11:47 AM.
04-22-11, 09:25 AM
#2
Easy start up for DSG is below average?
What does that even mean...
Is that because there's roll back with a DSG? I mean all you have to do is put some gas in it and it'll go forward, it's not like the driver has to thinka bout anything. Hell some slushboxes roll back on steep hills.
I think this is a moot point.
DSGs have average smoothness? That's adjustable by ECU. They're clutches, they can slip more if you want it to be more smooth. If you want more bite it slips less.
CVTs have bad high speed fuel economy? News to me. From what I understand CVTs are the best at fuel economy because it change ratios at any speed to get the best fuel economy the engine can provide for the given speed (obviously faster means you're consuming more fuel)
Sounds like all marketing BS. DSG takes advantages all day long.
What does that even mean...
Is that because there's roll back with a DSG? I mean all you have to do is put some gas in it and it'll go forward, it's not like the driver has to thinka bout anything. Hell some slushboxes roll back on steep hills.
I think this is a moot point.
DSGs have average smoothness? That's adjustable by ECU. They're clutches, they can slip more if you want it to be more smooth. If you want more bite it slips less.
CVTs have bad high speed fuel economy? News to me. From what I understand CVTs are the best at fuel economy because it change ratios at any speed to get the best fuel economy the engine can provide for the given speed (obviously faster means you're consuming more fuel)
Sounds like all marketing BS. DSG takes advantages all day long.
04-22-11, 09:53 AM
#4
Lexus Champion
Thread Starter
04-22-11, 10:25 AM
#5
Lexus Champion
From what I am reading, the Skyactiv automatic transmission is offering full range lockup feature. has this been offered by any other manufacturer yet?
Automatic transmissions (AT) can be categorized into three types:
Conventional AT: generates various gear reduction ratios with planetary gear sets CVT: generates various gear reduction ratios with a pair of pulleys Dual Clutch: utilizes 2 separate clutches for odd and even gear sets.
The key requirements for ATs are “good fuel economy”, “quick start-up” (including hill climbing), “direct feel” and “smooth shifting”.The table below shows the drawbacks and advantages of each transmission.
SKYACTIV-DRIVE is the ideal AT with all the advantages of the various types of transmissions:
The torque converter transfers engine power to the transmission through fluid, making a smooth start-up and gearshifts possible. The drawback is that fuel economy worsens due to the loss of power transfer through the fluid, and slippage during rapid acceleration, which causes vehicle speed to lag behind engine speed. Therefore, a torque converter with a lock-up clutch was developed, which locks the torque converter’s turbine to the impeller to improve fuel economy and direct drive feel. To improve fuel economy and direct drive feel pointed as challenges of Step AT shown in Fig.1, the lock-up range has to be maximized. However, in order to do so, we had to ensure NVH performance and clutch reliability.
Automatic transmissions (AT) can be categorized into three types:
Conventional AT: generates various gear reduction ratios with planetary gear sets CVT: generates various gear reduction ratios with a pair of pulleys Dual Clutch: utilizes 2 separate clutches for odd and even gear sets.
The key requirements for ATs are “good fuel economy”, “quick start-up” (including hill climbing), “direct feel” and “smooth shifting”.The table below shows the drawbacks and advantages of each transmission.
SKYACTIV-DRIVE is the ideal AT with all the advantages of the various types of transmissions:
The torque converter transfers engine power to the transmission through fluid, making a smooth start-up and gearshifts possible. The drawback is that fuel economy worsens due to the loss of power transfer through the fluid, and slippage during rapid acceleration, which causes vehicle speed to lag behind engine speed. Therefore, a torque converter with a lock-up clutch was developed, which locks the torque converter’s turbine to the impeller to improve fuel economy and direct drive feel. To improve fuel economy and direct drive feel pointed as challenges of Step AT shown in Fig.1, the lock-up range has to be maximized. However, in order to do so, we had to ensure NVH performance and clutch reliability.
Go Mazda!!!!!
04-22-11, 03:15 PM
#7
Trending Topics
04-22-11, 03:18 PM
#8
04-22-11, 07:00 PM
#12
Automatic Anxiety
In addition to the sweet-shifting six-speed manual, we drove each engine with Mazda’s new Sky-drive six-speed automatic, which boasts a more aggressive lock-up clutch for the torque converter, leading to a 4- to 7-percent improvement in fuel economy. Although the calibration was admittedly early in development, the automatic was distinctly less impressive than either of the new engines. In terms of feel, which Mazda claims is much more direct than before, it doesn’t seem to stand out from the current crop of high-tech automatics. The wide-open-throttle upshifts struck us as a bit lazy, too, although the downshifts were quite prompt. We’ll stick with the manual, thank you very much. Few buyers do, however, which could mean bad things for Mazda’s sales.
In addition to the sweet-shifting six-speed manual, we drove each engine with Mazda’s new Sky-drive six-speed automatic, which boasts a more aggressive lock-up clutch for the torque converter, leading to a 4- to 7-percent improvement in fuel economy. Although the calibration was admittedly early in development, the automatic was distinctly less impressive than either of the new engines. In terms of feel, which Mazda claims is much more direct than before, it doesn’t seem to stand out from the current crop of high-tech automatics. The wide-open-throttle upshifts struck us as a bit lazy, too, although the downshifts were quite prompt. We’ll stick with the manual, thank you very much. Few buyers do, however, which could mean bad things for Mazda’s sales.
Premium, 91-octane fuel is required for the Sky’s not-so-staggering 163 hp at 6000 rpm and 155 lb-ft at 4000, but Mazda is proud of its exceptionally wide torque band for enhanced real-world drivability. To enable running on regular gas, the U.S. version will have a compression ratio of 13:1, which means fuel economy and torque will diminish by about 3 to 5 percent, according to Mazda. The premium-fueled Sky we drove was perfectly adequate in the Mazda 6 prototypes, although acceleration was rather leisurely—far slower than the current Mazda 6 with its 168-hp, 2.5-liter—giving us plenty of time to wish for a bit more smoothness during the extended time in each gear. But being in the lighter Mazda 3 would help, and the tradeoff for near-diesel levels of fuel economy is probably worth it.
04-22-11, 07:33 PM
#13
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But that's on an individual basis. That document is saying ALL CVT's suck at highway fuel efficiency. NOT TRUE. You can get the ratio you want for best efficiency.
04-22-11, 07:44 PM
#14
but yeah, i mean it is PR piece... cant expect it to be too factual... reading it over, you would think they got 300lbs of torque and 50mpg from 2.0l engine.
04-22-11, 08:56 PM
#15
Lexus Champion
uhm, lets separate PR from reality :-)
http://forums.vwvortex.com/showthrea...amp-D-Car-News
Automatic Anxiety
In addition to the sweet-shifting six-speed manual, we drove each engine with Mazda’s new Sky-drive six-speed automatic, which boasts a more aggressive lock-up clutch for the torque converter, leading to a 4- to 7-percent improvement in fuel economy. Although the calibration was admittedly early in development, the automatic was distinctly less impressive than either of the new engines. In terms of feel, which Mazda claims is much more direct than before, it doesn’t seem to stand out from the current crop of high-tech automatics. The wide-open-throttle upshifts struck us as a bit lazy, too, although the downshifts were quite prompt. We’ll stick with the manual, thank you very much. Few buyers do, however, which could mean bad things for Mazda’s sales.
In addition to the sweet-shifting six-speed manual, we drove each engine with Mazda’s new Sky-drive six-speed automatic, which boasts a more aggressive lock-up clutch for the torque converter, leading to a 4- to 7-percent improvement in fuel economy. Although the calibration was admittedly early in development, the automatic was distinctly less impressive than either of the new engines. In terms of feel, which Mazda claims is much more direct than before, it doesn’t seem to stand out from the current crop of high-tech automatics. The wide-open-throttle upshifts struck us as a bit lazy, too, although the downshifts were quite prompt. We’ll stick with the manual, thank you very much. Few buyers do, however, which could mean bad things for Mazda’s sales.
Premium, 91-octane fuel is required for the Sky’s not-so-staggering 163 hp at 6000 rpm and 155 lb-ft at 4000, but Mazda is proud of its exceptionally wide torque band for enhanced real-world drivability. To enable running on regular gas, the U.S. version will have a compression ratio of 13:1, which means fuel economy and torque will diminish by about 3 to 5 percent, according to Mazda. The premium-fueled Sky we drove was perfectly adequate in the Mazda 6 prototypes, although acceleration was rather leisurely—far slower than the current Mazda 6 with its 168-hp, 2.5-liter—giving us plenty of time to wish for a bit more smoothness during the extended time in each gear. But being in the lighter Mazda 3 would help, and the tradeoff for near-diesel levels of fuel economy is probably worth it.
Higher compression ratio can bring problems: compression ignition (like a Diesel)/pre-ignition and hotter cylinder temperatures. The use of (more expensive) premium (higher-octane) fuel, direct gasoline injection with complex injectors and careful electronic monitoring and control will help.
Mazda claims that the lower North American compression ratio will not require the use of premium fuel, whereas the higher compression ratio in the rest of the world will.