d******g
发帖数: 6966 | 1 重复了C6的历史
http://media.gm.com/media/us/en/gm/news.detail.html/
content/Pages/news/us/en/2014/Apr/0407-corv8speed.html
DETROIT – An eight-speed paddle-shift automatic transmission will be
offered in the Chevrolet Corvette Stingray for 2015, enhancing the
performance and efficiency of the 2014 North American Car of the Year.
Designed and built by GM, the new transmission delivers world-class shift
times that rival the best dual-clutch designs.
The all-new, GM-designed 8L90 eight-speed is expected to contribute up to 5-
percent greater efficiency, when compared to the previous six-speed
automatic. EPA fuel economy test results are pending and will be announced
later. It also makes the Corvette Stingray one of the few sports cars to
offer the choice of a conventional manual transmission or an eight-speed
automatic.
“Corvette Stingray’s new eight-speed automatic delivers the comfort and
drivability of a true automatic transmission, as well as lightning-fast
shifts and the manual control that enhance the performance-driving
experience,” said Bill Goodrich, assistant chief engineer for eight-speed
automatic transmissions. “It was designed to enhance the Stingray’s
driving experience, with performance on par with dual-clutch designs, but
without sacrificing refinement.”
The available 8L90 transmission is based on the same eight-speed automatic
that will be offered on the supercharged 2015 Corvette Z06, but with unique
clutch and torque converter specifications matched to the torque capacity of
the Stingray’s LT1 6.2L naturally aspirated engine.
For performance driving, the transmission offers full manual control via
steering wheel paddles. A new transmission-control system and unique
algorithms deliver shift performance that rivals the dual-clutch/semi-
automatic transmissions found in many supercars – but with the smoothness
and refinement that comes with a conventional automatic fitted with a torque
converter.
The transmission controller analyzes and executes commands 160 times per
second. Wide-open throttle upshifts are executed up to eight-hundredths of a
second quicker than those of the dual-clutch transmission offered in the
Porsche 911.
Smaller steps between gears, compared to the previous six-speed automatic,
keep the engine within the sweet spot of the rpm band, making the most of
its horsepower and torque to optimize performance and efficiency.
With four gearsets and five clutches, creative packaging enables the new
eight-speed automatic to fit the same space as the previous six-speed
automatic. Extensive use of aluminum and magnesium make it more than eight
pounds, or 4 kg, lighter than the six-speed. Design features that reduce
friction contribute to the expected 5-percent greater efficiency.
The 8L90 is built at GM’s Toledo, Ohio, transmission facility. |
x*b
发帖数: 5723 | 2 刚要发被你抢先了: ）
这是个大好事啊，不过我对这个换档速度还是表示怀疑，最慢的PDK换档时间也就150ms
，GT3上的PDK-S <100ms，最快的PDK(918上的)50MS左右，如果GM说"up to eight-
hundredths of a second quicker than those of the dual-clutch transmission
offered in the Porsche 911"就代表8L90可以做到70ms? Either GM had wrong data
on PDK or the engineer is bad on math...
我觉得实际点8L90最多能做到100MS就不错了。 |
c*********r
发帖数: 19468 | 3 这类说法其实都很tricky，看你怎么定义换档时间了……我觉得AT和DCT本来就没有直
接比较的意义
不过8L90换档应该是很快，否则也不敢给Z06用吧……
150ms
data
【在 x*b 的大作中提到】
: 刚要发被你抢先了: ）
: 这是个大好事啊，不过我对这个换档速度还是表示怀疑，最慢的PDK换档时间也就150ms
: ，GT3上的PDK-S <100ms，最快的PDK(918上的)50MS左右，如果GM说"up to eight-
: hundredths of a second quicker than those of the dual-clutch transmission
: offered in the Porsche 911"就代表8L90可以做到70ms? Either GM had wrong data
: on PDK or the engineer is bad on math...
: 我觉得实际点8L90最多能做到100MS就不错了。
|
d******g
发帖数: 6966 | 4 哈,这种宣传文章里面的东西听听就可以了. 最后能达到zf 8at那几个运动版的水平就
很不错了. dct不单单是换档速度,那个换档的机械质感自动档很难复制. 总之相对于本
来的6at肯定是提升巨大,再说dct也不是万能的,如果要换的档不在另一个离合器上换档
速度还是挺慢的.
150ms
data
【在 x*b 的大作中提到】
: 刚要发被你抢先了: ）
: 这是个大好事啊，不过我对这个换档速度还是表示怀疑，最慢的PDK换档时间也就150ms
: ，GT3上的PDK-S <100ms，最快的PDK(918上的)50MS左右，如果GM说"up to eight-
: hundredths of a second quicker than those of the dual-clutch transmission
: offered in the Porsche 911"就代表8L90可以做到70ms? Either GM had wrong data
: on PDK or the engineer is bad on math...
: 我觉得实际点8L90最多能做到100MS就不错了。
|
x*b
发帖数: 5723 | 5 我觉得调校的好应该和ZF最快的8HP有一比？不过不知道可靠性和ratio调教的如何？碳
大怎么看？
【在 c*********r 的大作中提到】
: 这类说法其实都很tricky，看你怎么定义换档时间了……我觉得AT和DCT本来就没有直
: 接比较的意义
: 不过8L90换档应该是很快，否则也不敢给Z06用吧……
:
: 150ms
: data
|
x*b
发帖数: 5723 | 6 应该主要还是那个机械质感没法模拟吧，但是无论如何是个好事儿，这样C7性能就更好
而且更超值了.
于本
【在 d******g 的大作中提到】
: 哈,这种宣传文章里面的东西听听就可以了. 最后能达到zf 8at那几个运动版的水平就
: 很不错了. dct不单单是换档速度,那个换档的机械质感自动档很难复制. 总之相对于本
: 来的6at肯定是提升巨大,再说dct也不是万能的,如果要换的档不在另一个离合器上换档
: 速度还是挺慢的.
:
: 150ms
: data
|
z*****7
发帖数: 888 | |
V***b
发帖数: 3419 | 8 换挡速度除了取决于变速器的工艺水平，还和车本身有关。
1. 发动机扭矩输出，扭矩越大，换档越慢，torque converter/clutch需要更多时间降
伏大扭矩发动机。
2. RWD or AWD，RWD上的变速器没有前驱动轴和前差速器拖累，换档更快。
3. NA or Turbo，NA引擎blip throttle比turbo快，变速器换档也快。
所以，C7 8AT如果换档慢只能说GM是个sb |
B*Z
发帖数: 7062 | 9 8at比6at齿轮比例密集，所以降档匹配转速应该更快。至于升档，要那么快干什么？慢
慢搞不就是rev match了？
【在 V***b 的大作中提到】
: 换挡速度除了取决于变速器的工艺水平，还和车本身有关。
: 1. 发动机扭矩输出，扭矩越大，换档越慢，torque converter/clutch需要更多时间降
: 伏大扭矩发动机。
: 2. RWD or AWD，RWD上的变速器没有前驱动轴和前差速器拖累，换档更快。
: 3. NA or Turbo，NA引擎blip throttle比turbo快，变速器换档也快。
: 所以，C7 8AT如果换档慢只能说GM是个sb
|
c**********9
发帖数: 135 | 10 这个问题就是单一性的问题。
The transmission controller analyzes and executes commands 160 times per
second.
这个句话没说，或者说这个不是DCT和AT之间的区别。或者说大家都是相似的，你可以
这么做，我也可以，都是ECU软件分析+液压硬件执行。 |
s***i
发帖数: 10182 | |
