Active Noise Compensation, Basic Function - GF82.62-P-9902A
Model All (CAR)
Overview
This document contains information on:
- General
- Function requirements
- Function
- Engine noise reduction through active noise compensation
- Driving noise reduction through active noise compensation
- Compensation for lack of engine noise (e.g. 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
Function
Engine noise reduction through active noise compensation
The sound generator control unit or the sound system amplifier control unit evaluates microphone signals to detect engine noise in the vehicle interior. In vehicles up to and including telematics unit version (NTG) 6, separate microphones are used for this purpose. As of NTG 7, the microphones for the hands-free system are used or they are also used for it.
The sound generator control unit also evaluates engine data, in particular, data about cylinder deactivation. To reduce the level of audible, disruptive, low-frequency engine noise in the vehicle interior, the sound generator control unit or the sound system amplifier control unit calculates counter signals based on these signals.
The speaker system emits the counter signals as sound waves. This is also done even if 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.
On vehicles up to and including telematics unit version (NTG) 6, the sound system amplifier control unit reduces the engine noise. The sound generator control unit takes over this function as of NTG 7.
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 over the audio bus.
Compensation for lack of engine noise (e.g. in hybrid and electric vehicles)
If the level of noise development is too low (e.g. on electric motors), the simulation of engine noise 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 over audio bus.
As well as acoustic noise compensation, haptic feedback is also provided on some vehicles through the generation of vibrations at the steering wheel.
| Function schematics | |||
|---|---|---|---|
| Function schematic for actuating speakers | Model 223 with engine 279.9 except code 96B (Road noise cancellation via speakers (RNC)) except code 97B (Engine noise reduction via speakers (EOC)) 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 232 | PE82.62-P-2501-97J | ||
| Model 290 as of model year 2021 with code 811 (High-End sound system) with code 97B (Engine noise reduction via speakers (EOC)) Model 290 as of model year 2021 with code 97B (Engine noise reduction via speakers (EOC)) except code 811 (High-End sound system) except code ME10 (Hybrid vehicle (plug-in, PHEV)) | PE82.62-P-2501-97F | ||
| Model 295 with code MEF2 (AMG Entry variant with M battery + 4MATIC) Model 296, 297 with code MEF3 (AMG Entry variant with L battery + 4MATIC) | PE82.62-P-2501-97I | ||
| Further basic functions | |||
| Sound generator control unit basic function | GF82.27-P-9890A | ||
| Sound system amplifier control unit, basic function | Model 290 as of model year 2021 with code 810 (Premium sound system) with code 97B (Engine noise reduction via speakers (EOC)) Model 290 as of model year 2021 with code 811 (High-End sound system) with code 97B (Engine noise reduction via speakers (EOC)) |
GF82.62-P-9890A |