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Home >> Volvo >> 2012 >> S60 R Design AWD L6-3.0L Turbo VIN 90 B6304T4 >> Repair and Diagnosis >> Accessories and Optional Equipment >> Collision Avoidance and Parking Assist Systems >> Description and Operation >> Closing Velocity Module (CVM) >> Function

Function






Function

Driver's responsibility

Note! It is always the responsibility of the driver to ensure that there is a sufficient distance to the vehicle ahead and that the speed is adjusted to the current traffic conditions.

City Safety




Closing velocity module (CVM) (4/125) communicates continuously with Brake control module (BCM) (4/16), Engine control module (ECM) (4/46), Climate control module (CCM) (not XC60 before structure week 201046), Climate control module (CCM) (not XC60 before structure week 201046), combination instrument (DIM) (5/1), and Supplemental restraint system module (SRS) (4/9). Control modules receive information if there is a risk of collision with vehicles in front of your own vehicle.
The Closing velocity module (CVM) is included in the support function City Safety and its main task is to prevent or minimize the affects of low speed collisions.
When the engine is started, the support function City Safety is always activated and it is active within the speed range of 4 - 30 km/h.
On S60 (11-), S80 (07-), S80L, V70 (08-), XC70 (08-), and V60 as well as XC60 from 201046, the driver can turn off the function during the existing driving cycle via the menu in Infotainment control module (ICM).
If the speed difference is 4-15 km/h related to the car ahead then City Safety can completely avoid a collision.
If the speed difference is 15-30 km/h between the vehicles, City Safety can not avoid collision on its own - for full brake force the driver has to press on the brake pedal and then it may be possible to avoid a collision even at differences above 15 km/h.

The Closing velocity module (CVM) can request different functions depending on the actual situation:
- preloading the brake system
- automatic braking
- torque limiting in engine
- brake assistance EBA.
Preloading the brake system
For as fast a response as necessary when braking, the brake system's hydraulic pump activates at exactly the time the Closing velocity module (CVM) requests automatic braking of the vehicle.
When the hydraulic pump is activated, the brake pads move closer to the brake discs, which shortens the vehicle braking distance when braking.
Preloading the brake system does not affect the driver or passengers in the vehicle.
Automatic braking
Automatic braking is initiated by the Closing velocity module (CVM) when there is a risk of a collision with a vehicle ahead. The request for automatic braking is sent via the CAN network from the Closing velocity module (CVM) to the Brake control module (BCM).
Torque limiting in engine
During automatic braking, the engine torque is limited so as not to affect vehicle braking. The request for torque limiting is sent via the CAN network from the Closing velocity module (CVM) to the Engine control module (ECM) (4/46).
Emergency Brake Assistance (EBA)
During automatic braking, the parameter for the request for brake assistance EBA reduces. This means that the driver does not have to press as hard on the brake pedal in order for EBA to be activated.
Brake assistance, EBA, is activated by the Brake control module (BCM) by the hydraulic pump increasing the brake pressure in the brake system, so that optimal brake effect with the ABS function is achieved.
For further information about brake assistance, EBA, see Design and Function, Brake control module (BCM).

Seatbelt force limitation (not S80 (07-), S80L, V70 (08-), and XC70 (08-))
The air bag supplemental restraint system communicates with the Supplemental Restraint System Module (SRS) via an internal CAN network (XC60 and V60) or sensor-CAN (S60 (11-)). The Supplemental Restraint System Module (SRS) optimize the function for Adaptive Seatbelt force limiting in the event of a collision based on signals from the Closing velocity module (CVM).
For further information about seatbelt force limiting, see Design and Function, Supplemental restraint system module (SRS).

Active/passive driver
The Closing velocity module (CVM) determines whether the driver seems to be active by using signals regarding the accelerator pedal and steering wheel movements.
If the driver is deemed to be active and has the situation under control, the Closing velocity module (CVM) does not request automatic vehicle braking.
If the driver goes from being passive to being active, the Closing velocity module (CVM) cancels the request for automatic braking and the driver regains full control of the vehicle.

Driver information
The Closing velocity module (CVM) sends information to the driver via text message, symbols and the indicator lamp in the Driver information module (DIM) (5/1).

The following text messages can appear in the Driver information module (DIM):
- Message indicating that automatic braking has been requested by the Closing velocity module (CVM). The message remains until it is confirmed by the driver.
- Message indicating that there is a fault in one part of the support function City Safety. The function is switched off if the message appears in the vehicle.
- Message that the sensor on the windshield is blocked, for example, if a flag indicating long load on the roof hangs down in front of the sensor. From structure week 200835 the message also applies to forward-facing camera, connected to Forward Sensing Module (FSM).

Adaption after wheel alignment
The Closing velocity module (CVM) uses information from the Brake control module (BCM) to determine whether there is any lateral acceleration.
The value for lateral acceleration is compared with the current steering wheel angle and the Closing velocity module (CVM) continually adapts using the lateral acceleration value.
After carrying out wheel alignment, the Closing velocity module (CVM) is automatically adapted.

Miscellaneous
There are two types of vehicle windscreen, IR or standard windscreen.
The Closing velocity module (CVM) receives information about which type of windscreen the vehicle has via the vehicle configuration file in the Central electronic module (CEM). It is important that the same type of windscreen is installed in the event of replacement, otherwise the performance of City Safety deteriorates.
For further information about using the support function City Safety, see the vehicles manual.

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