PRE-RELEASE
Intake manifold, VIM
| Intake manifold, VIM |
To increase the engine torque over a wide range of engine speeds, the intake manifold has valves that can control the air so that it either travels a short way or a long way. To improve the engine torque at low speeds, the valves are left closed, which gives the air a longer path to travel. This improves the fill factor in the cylinders, this is also known as volumetric efficiency (VE). At high speeds, the valves open and air travels a shorter path, which means that the restriction losses in the intake manifold are reduced. This gives the engine a relatively high torque over a wide register. In the engine speed range 2400-5700 rpm, at least 90% of the maximum torque is available, which is much thanks to the variable intake manifold.
See Control valve VIM throttle (454), Simtec
