Function
Function
Controlling the adaptive cruise control
The function adaptive cruise control is an extension of the existing cruise control. If there is no vehicle ahead, the speed will remain unchanged as for conventional cruise control. Speed is set by the driver in a similar way as for conventional cruise control.
If there is a vehicle ahead traveling at a lower speed than the set speed, the speed will adjust itself automatically so that the set time gap to the vehicle ahead is attained. In this case, the adaptive cruise control in Forward Sensing Module (FSM) controls the Engine control module (ECM) and, if necessary, also Brake control module (BCM) to maintain the set time gap.
The time gap to the vehicle ahead is set by the driver in five steps, in the interval 1 to 3 seconds. If no earlier setting has been made, then step 3 of 5 will be used as basic value.
When the system is activated, the last selected interval from the previous driving cycle is used.
To change the interval setting, the driver presses one of the buttons on the Steering wheel switch left (SWSL) to increase or reduce the interval. Steering wheel switch left (SWSL) transmits information via LIN communication to Central electronic module (CEM) (4/56), stating which button has been activated. The Central electronic module (CEM) forwards the information via the CAN network to the Forward Sensing Module (FSM) (4/80).
The function adaptive cruise control is, on vehicles with manual transmission, limited to a speed higher than approx. 30 km/h. Vehicles with automatic transmission have a function making it possible to adapt the speed to the vehicle ahead also below 30 km/h. Should the vehicle ahead stop, the adaptive cruise control will stop the vehicle and hold it still using the service brake. The service brake will only hold the vehicle still for max. 120 seconds, after this the parking brake automatically takes over the task of holding the vehicle still. The parking brake will also be applied automatically when the adaptive cruise control has followed a vehicle to stop and the driver door is opened or the engine is turned off. When the vehicle ahead drives off, and your own vehicle has been at a standstill for a number of seconds (time may vary between 0 - 3 seconds depending on the situation), the driver has to reactivate the adaptive cruise control for the vehicle to follow. Reactivation is performed by pressing the resume button or by lightly pressing the accelerator pedal which also, when needed, releases the parking brake.
Thus the adaptive cruise control cannot start the vehicle automatically after the vehicle has been stopped.
Note! To activate the adaptive cruise control the driver has to close the door, buckled the seatbelt, and then pressed at least once either on the accelerator pedal or the brake pedal. This is a way to ensure that the driver is in the car, before allowing activation.
Controlling the cruise control
See: Design and Function - Engine control module (ECM).
Automatic brakes and brake support
The brake support function in the event of a collision risk is designed to aid the driver in obtaining the necessary brake effect that he/she requests from the vehicle in situations where there is a risk of a collision.
Automatic brake function brakes the vehicle in the event of an unavoidable collision without the driver having to touch the brake pedal.
Vehicles equipped with a Forward Sensing Module (FSM) (4/80) have a forward facing camera (27/5) installed by the rear view mirror, and in some vehicles, there is also a Forward Looking Radar (FLR) (7/203) installed in the front (behind the grill). Forward Looking Radar (FLR) is only in vehicles equipped with adaptive cruise control, collision warning, automatic braking/brake support, and distance control.
Forward Looking Radar (FLR) measures the distance and speed to the vehicle ahead that is in its field of view.
The forward facing camera helps to classify the target within its field of view. The Forward Sensing Module (FSM) uses the information from the Forward Looking Radar (FLR) to assess the threat of a collision with the vehicle in front moving in the same direction. The Forward Sensing Module (FSM) uses the threat assessment of a collision, together with the assessment of what the driver will do, to react to one or several different types of warnings to the driver and also with amplified brake control and automatic brake.
In the event of an imminent collision the Forward Sensing Module (FSM) can carry out the following:
1. An audible signal and/or a visual warning (See Collision warning).
2. A low level of self-controlled braking force before the driver has depressed the brake pedal.
3. A reduction of the force that is required to achieve the full braking capacity of the vehicle.
4. Automatic braking to reduce the collision speed.
The required effect of the function is to maximize the braking effect for the driving conditions where there is a risk of a collision with the approaching vehicle. The brake system achieves maximum efficiency through an increase of braking torque. This reduces the total braking distance without negatively affecting the driver, passengers or the behavior of the vehicle. In the event of a possible collision the brake assistance function triggers braking to minimize delays in the braking system and increases the driver's ability to brake.
In order to carry out a brake activation, brake support or automatic braking, the Forward Sensing Module (FSM) communicates with the Brake control module (BCM) (4/16), which in turn activates the hydraulic unit.
The main component in the function is the hydraulic modulator, which is integrated with the Brake control module (BCM). The primary function of the hydraulic modulator is to create the required brake pressure, which is based on a control signal. The hydraulic modulator is an electromechanical component that receives control signals from the Brake control module (BCM). The Brake control module (BCM) supplies the hydraulic modulator with sufficient control signals based on the driver's actions, the vehicle's speed and the information from the Forward Sensing Module (FSM). The hydraulic modulator achieves the desired brake pressure/brake torque for each wheel, based on the requested brake effect set using necessary information.
The Forward Sensing Module (FSM) requires, except to be able to control the hydraulic modulator, information from the Brake control module (BCM).
Information that the Forward Sensing Module (FSM) requires:
- stoplamp switch
- brake pedal position switch
- speed
- calculated braking force.
For more information about the Brake control module (BCM), see Design and Function, Brake control module (BCM).
Collision warning
The collision warning function is designed to warn at high likelihood of collision with the vehicle ahead or a person. The collision Warner warns for vehicles driving in the same direction as your own as well as stationary vehicles. The collision Warner warns for persons crossing or along your vehicle's travel direction where there is a high risk of collision.
The collision warning function calculates when a warning shall be activated based on speed and direction of the vehicle ahead or person has as well as your own vehicle's speed and direction. In the calculation there is compensation for the normal reaction time that approx. 85% of all drivers have and for the system's response time. If the warning distance is greater than the measured distance to the vehicle ahead and the driver has not taken any action, a collision warning will be activated. For the warning to be effective and for the driver to have time to react, the initial distance may not be shorter than for it to be physically possible to stop the vehicle/avoid the collision. The collision warning consists of combined light and sound.
There are three possible warning distances that can be set via the menu system in Infotainment control module (ICM) (3/281). This setting controls when the warning is activated. In the same menu the driver can also turn the function and the warning sound on and off.
The visual warning is generated by means of the indicator, visual collision warning (27/2) and the audible warning is generated by means of the Driver information module (DIM) (5/1). The Forward Sensing Module (FSM) (4/80) transmits a request via CAN to the Driver information module (DIM), which generates the audible warning. The Forward Sensing Module (FSM) also transmits a request to the Infotainment control module (ICM) (3/281) to lower the sound (stereo) to the speakers during the period that the audible warning is generated by the Driver information module (DIM).
The collision warning function shall activate a warning so that approx. 85% of all drivers have a chance of stopping or reducing a collision with a vehicle ahead in a situation where a collision is imminent, on the condition that you maintain a time distance of more than 2 seconds to the vehicle ahead.
The collision warning function shall activate a warning so that approx. 85% of all drivers have a chance to stop, steer aside, or reduce the effects of a collision with a vehicle or a person fulfilling the mentioned criteria.
Distance control
Distance control is a function that informs of the time interval to the vehicle in front.
If the time interval is less than the distance that has been set, the driver is informed of this via a continuously lit light indication in the windscreen. The light indication is generated by the visual collision warning indicator (27/2). Distance control is based on target data taken from Forward Looking Radar (FLR).
The switch for distance control is located in the center console.
The time interval and setting of this is the same as adaptive cruise control and is carried out using the arrow buttons in on the steering wheel. Distance control can only be active when the adaptive cruise control is off or in stand-by mode.
The distance control function can be active at speeds greater than 30 km/h.
Lane Departure
Warning
The Lane Departure Warning function is designed to give a warning when the vehicle is about to leave the lane inadvertently. Lane Departure Warning calculates when to activate a warning based on the position of the vehicle in relation to the lane's road markings.
The system consists of a camera (27/5) that reads the lanes painted road markings.
The driver is warned via an audible signal when the vehicle crosses the lane's road markings without using the indicators. A warning is only given if there are road markings on both sides of the lane and the vehicle is not performing exaggerated maneuvers.
The audible warning is generated via the Driver information module (DIM) (5/1). The Forward Sensing Module (FSM) (4/80) transmits a request via CAN to the Driver information module (DIM) which generates the audible warning. The Forward Sensing Module (FSM) also transmits the request to the Infotainment control module (ICM) (3/281) to silence the stereo sound from the loudspeakers during the period that the audible warning is generated by the Driver information module (DIM).
The switch for Lane Departure Warning is located in the center console.
Driver Alert
Control
The Driver Alert Control function is designed to attract the driver's attention when it senses swerving driving behavior, for example if the driver is distracted or is on the verge of falling asleep.
The forward sensing camera (27/5) reads the lane's road markings and compares the stretch of road with the driver's steering wheel movements. The driver is warned via an audible signal when the vehicle does not continuously follow the lane.
The audible warning is generated via the Driver information module (DIM) (5/1). The Forward Sensing Module (FSM) (4/80) transmits a request via CAN to the Driver information module (DIM) which generates the audible warning. The Forward Sensing Module (FSM) also transmits the request to the Infotainment control module (ICM) (3/281) to silence the stereo sound from the loudspeakers during the period that the audible warning is generated by the Driver information module (DIM).