Active Noise Compensation, Basic Function - GF82.62-P-9902A
Model all (CAR)
with code 96B (Road noise cancellation via speakers (RNC))
Model all (CAR)
with code 97B (Engine noise reduction via speakers (EOC))
Model all (CAR)
with code MEF3 (AMG Entry variant with L battery + 4MATIC)
Overview
This document contains information on:
- Engine noise reduction through active noise compensation
- Driving noise reduction through active noise compensation
- Compensation for lack of engine noises in hybrid and electric vehicles
General
Active noise compensation identifies unwanted noises in the vehicle interior and neutralizes them by generating counter signals (inverted signal).
In electric vehicles, the active noise compensation ensures engine noise in the vehicle interior. This provides the driver with acoustic feedback about the respective driving situation.
Function requirements:
- Circuit 30t, for driving noise reduction and compensation for lack of engine noises in hybrid and electric vehicles
- Engine running, for engine noise reduction
Engine noise reduction through active noise compensation
On older vehicles up to and including telematics unit version (NTG) 6, the sound system amplifier control unit performs engine noise reduction. The sound generator control unit takes over this function as of NTG 7.
The control unit evaluates microphone signals to detect engine noises in the vehicle interior. Separate microphones are used for this in older vehicles. In newer vehicles, the control unit accesses signals from the microphones for the hands-free system.
The control unit additionally evaluates engine data, particularly data on cylinder deactivation. To reduce audible, obtrusive low-frequency engine noises in the vehicle interior during cylinder deactivation, the control unit calculates counter signals on the basis of these signals.
The speaker system outputs the counter-signals even when no audio source is active. If audio output is active, the counter-signals expand the current audio source. The counter-signals overlay the engine noises in the vehicle interior and eliminate them almost entirely.
Driving noise reduction through active noise compensation
The sound generator control unit performs the following actions to implement the function:
- Receiving and evaluating from acceleration sensors at the wheels and axles
The acceleration sensors supply a reference signal from which the rolling noises are derived.
- Receiving and evaluating engine data via the CAN interface
- Receiving and evaluating microphone signals
The transmission path in the vehicle interior is monitored using microphones.
- Generating the forwarding the counter-signals via audio bus
Compensation for lack of engine noises in hybrid and electric vehicles
The low noise development of electric motors means that the simulation of engine noises linked to the driving situation can improve the driving experience. This also includes acoustic feedback when the engine is switched on and off. The engine sound is tuned to the selected transmission mode. The speaker system outputs the simulated sound even when no audio source is active. If audio output is active, the simulated sound expands the current audio source.
The sound generator control unit performs the following actions to implement the function:
- Receiving and evaluating engine data via the CAN interface
- Generating and forwarding the simulated signals via audio bus
As well as acoustic noise compensation, haptic feedback is also provided through the generation of vibrations at the steering wheel.
| Function schematics | |||
| Function schematic for actuating speakers | Model 223 with code 96B (Road noise cancellation via speakers (RNC)) Model 223 with code 97B (Engine noise reduction via speakers (EOC)) | PE82.62-P-2501-97G | |
| Model 290 with code 97B (Engine noise reduction via speakers (EOC)) | PE82.62-P-2501-97F | ||
| Model 297 with code MEF3 (AMG Entry variant with L battery + 4MATIC) | PE82.62-P-2501-97I | ||
| Further basic functions | |||
| Speaker system, basic function | GF82.62-P-9900A | ||
| Control units | |||
| Active sound generator control unit for engine sound, basic function | GF82.60-P-9891A | ||
| Sound system amplifier control unit, basic function | Model 290 with code 810 (Premium sound system) with code 97B (Engine noise reduction via speakers (EOC)) Model 290 with code 811 (High-End sound system) with code 97B (Engine noise reduction via speakers (EOC)) |
GF82.62-P-9890A |