问 请问gle450用的是双涡轮双涡管增压发动机吗？

摘取和涡轮相关的

4. An Electric Supercharger

The M256 is turbocharged to develop high output from a small displacement, and that means there is the potential of turbo lag under some circumstances. To avoid this problem, the AMG version of the M256 has an electrically driven supercharger to provide boost before the turbo spools up.

This supercharger, which is located downstream of the turbocharger, uses a centrifugal flow compressor—like the compressor side of a turbo—driven by a 48-volt electric motor. It spins to 70,000 rpm and can develop a peak boost pressure of about 6.6 psi. That’s enough to provide strong engine response while the turbo gets up to speed, at which point a check valve closes and the turbo takes over from the electric supercharger.

5. A Large Turbocharger

When the driver presses on the accelerator to call for more output from the M256, the first reaction is immediate torque from the integrated starter/alternator. Then the electric supercharger spins up in 0.3 second to deliver useful boost. With these two quick responses, there’s no need to fit a tiny turbocharger to minimize turbo lag.

Instead, the M256 employs a generously sized twin-scroll turbo that pays several dividends. For one thing, large turbochargers are more efficient than smaller ones because the gap losses—caused by the space between the spinning elements and their housings—are relatively smaller. For another, a larger turbocharger flows better and creates less back pressure at high rpm, extending the engine’s powerband.

Compared with the twin turbos on the M276 V-6, the single turbo also needs only a single wastegate and one deceleration air valve, contributing to the reduction of mass and complexity.

M256通过涡轮增压以小排量产生高输出，这意味着在某些情况下存在涡轮滞后的可能性。为避免此问题，AMG版本的M256具有电动增压器，可在涡轮加速之前提供增压。

该增压器位于涡轮增压器的下游，它使用由48伏特电动马达驱动的离心流式压缩机（类似于涡轮机的压缩机侧）。它旋转至70,000 rpm，可以产生约6.6 psi的峰值增压压力。这足以在涡轮加速时提供强大的发动机响应，此时止回阀关闭，涡轮从电动增压器接管。

5.大型涡轮增压器

当驾驶员踩油门以要求从M256输出更多功率时，第一反应是来自集成的启动器/交流发电机的即时扭矩。然后，电动增压器在0.3秒内旋转以提供有用的升压。通过这两个快速响应，无需安装小型涡轮增压器即可将涡轮滞后时间降至最低。

取而代之的是，M256采用了大尺寸的双涡管涡轮增压技术，可以带来很多好处。一方面，大型涡轮增压器比小型涡轮增压器效率更高，因为间隙损失（由纺丝元件及其壳体之间的空间所引起）相对较小。另一个原因是，较大的涡轮增压器流动性更好，并在高转速下产生较小的背压，从而扩大了发动机的功率范围。

与M276 V-6上的双涡轮增压器相比，单涡轮增压器还只需要一个废气门和一个减速空气阀，从而有助于减轻质量和复杂性。