4
Audi of America
2013 Audi A7/S7
REVISED JULY 2012
All information subject to change
Highlights
Key Attributes
*Refer to Equipment pages for how to acquire
Audi cylinder on demand™ technology
*
Audi cylinder on demand technology with
active motor mounts and noise cancellation improves mpg up to ten percent. With
transitions in less than 1/400,000 of one second:
1 - 5 - 4 - 8 - 6 - 3 - 7 - 2 1 - 5 - 4 - 8 - 6 - 3 - 7 - 2
1. Two active motor mounts use crankshaft position sensor and built in accelerometers to
detect normal V4 vibrations between 25 & 250 hz; motor mounts are electromagnetic coils
(similar to speakers) incased in hydraulic fluid which transmit opposite phase vibrations to
cancel incoming vibrations from passing through motor mounts. These mounts also work
during V8 idle and over rough roads (low frequency vibrations between 7 – 15 hz).
2. Four microphones embedded in the headliner detect normal V4 acoustic changes and
transmit sound waves, using the vehicle’s Bose® or B&O® speakers (in the on or o position),
of the same amplitude but 180 degrees out of phase thus diminishing undesirable noise
from reaching the ears.
3. V4 mode uses cylinders 1, 4, 6 & 7 & is accomplished by an electromagnetically
controlled camshaft which rotates into a zero lift camshaft profile; the other cylinders are
shut down and fuel injection/ignition halted after first taking in air to act as an air spring for
reduced power loss. V4 transition will occur in a fraction of a second under these conditions
(coolant temperature of 86 degrees, third gear or higher and between 960 & 3,500 rpm).
V4 mode can last for up to seven minutes at which point all cylinders are engaged to prevent
excessive heat loss and eciency.
4. Active motor mounts and noise cancellation system are close-looped, unlike other
systems available up until now which provide a fixed level of noise and vibration cancellation
over a more narrow band of reduced cylinder operation. Closed-loop monitoring provides
a greater range of adaptation to vibration and noise, thus allowing V4 mode over a wider
engine range and thus improved eciency.
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