Head-On Collision (USA/Can Only)

Fig 1: Identifying Multi-Point Detection Function (USA/CAN)

Courtesy of VOLVO CARS CORPORATION

In the event of a head-on collision, a function called multi-point detection is used. This means that the collision pulse is registered at several points. This function is integrated in the supplemental restraint system module (SRS) (4/9). When the collision pulse is sufficiently large, a deployment signal (current pulse) is sent to:

• front airbags (8/123 and 8/124) and/or
• belt tensioners (8/33, 8/34, 8/55, 8/56, and 8/62) and, if certain conditions are met, also to
• the inflatable curtains (8/66 and 8/67).

The front impact sensors (7/178 and 7/179) (not XC60)are also part of the control module's multi-point detection. They register the collision pulse and send acceleration data to the control module. The driver and front passenger airbags are deployed. The belt tensioners are deployed. The inflatable curtains may be deployed. In a head-on collision in which the front airbags and front belt tensioners have been deployed, the adaptive belt force limitation function (see below) could also be activated. If the driver's airbag is deployed and the driver's seat belt is fastened, the control module sends a deployment signal (current pulse) to the adaptive steering column (8/99). The front passenger airbag will not be deployed if it has been disabled via the occupant weight sensor (OWS) (7/93).

A impact signal is sent on a directly connected cable from the Supplemental restraint system module (SRS) to the Central electronic module (CEM) (4/56) when the impact protection has been activated.

An impact status signal is also transmitted to the Central electronic module (CEM) on the CAN. The Central electronic module (CEM) ensures that:

• switch off the fuel pump (FP)
• switch off the windshield wipers when the car is stationary
• turn off defrosting of windows and rearview mirrors if the vehicle is stationary
• light the interior lighting
• light the flashing hazard lights
• unlock the central locking system
• turn off the fuel engine heater

Supplemental restraint system module (SRS) receives continuous information from Closing velocity module (CVM) (4/125) (only XC60). With laser Closing velocity module (CVM)detects if the vehicle is about to collide with an object in front. Information is used by Supplemental Restraint System Module (SRS) to get an early indication that the vehicle is about to collide, which helps to decide what type of action is needed.