Park assist systems are designed to help the driver during parking
manoeuvres. The most used systems are those with ultrasonic parking sensors or
a rear camera.
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Camera rear view |
Ultrasonic parking system
This is based on the use of sensors installed in
the bumpers distributed strategically to cover a wide area. These sensors are
mounted on the rear bumper and optionally on the front and are controlled by a
control unit.
The system is activated automatically on engaging reverse gear, the
sensors are activated and emit an ultrasonic pulse that travels through the
air. If there is an obstacle, the ultrasonic pulse will rebound from it and
return to the sensor which will detect the pulse and inform the control unit.
The control unit makes the calculation of the distance to the obstacle based on
the time elapsed between the emission and the reception of the pulse. The
maximum detection distance is approximately 0.8 to 1 metre.
The control unit emits an acoustic warning so that the driver knows the
distance of the obstacle. These warnings are transmitted through independent
loudspeakers or through the vehicle's audio system. As the vehicle nears an
obstacle, the repeat rate of the audible warning increases. When the object is
less than 30 centimetres from the centre of the vehicle’s bumper, the acoustic
warning will sound continuously.
If the driver does not wish to use park assist, there is a switch for
enabling or disabling the ultrasonic parking system. This is located in the
cabin, generally in the centre of the dashboard or in the central console.
Rear camera system
This system uses a small video camera and a screen
for displaying the images.
The rear camera is located at the rear of the vehicle and strategically
focused to assist parking. In the same way as the ultrasonic parking system, it
is activated automatically on engaging reverse gear.
This system uses a control unit which manages the
system, which, if the vehicle also has the ultrasonic parking system installed,
one unit may be used for both systems.
The transmitted images are displayed on the video screen. This screen may be
independent or may be shared with other systems, such as the navigation system.
Lines are shown in the screen that determine fixed distances for assisting the
driver when parking. The lines are green, yellow and red. The red line measures
the distance between the rear bumper and 30 cm behind it, and the yellow line
measures between 30 cm and 60 cm behind the bumper.
Parking space
measurement
systems
This
system measures the size of a parking space in comparison with the length of
the vehicle. This system uses ultrasonic parking sensors that are located on
the sides of the vehicle.
The measuring of an available space is activated when the system is
selected with the switch, the speed of the vehicle is less than 20 km/h and the
direction indicator of the measuring side is activated.
The screen will show different images depending on whether the space is
ample for parking the vehicle, is just sufficient or is too small.
• The available parking space measurement system is deactivated in the
following cases:
• When the ignition is turned off.
• When the reverse gear is engaged.
• When the speed of the vehicle exceeds 70 km/h for
more than one minute.
• 10 seconds after turning off the direction
indicator.
• When the electrical connection for the tow hitch
is connected.
• On pressing the available space measurement switch
for deactivating the system.
Automatic parking systems
This assist system is an active function that aids
the execution of the manoeuvres when reverse parking. The automatic parking
system is capable of automatically steering the vehicle for parking. The only
thing that the driver has to do in this case is operate the accelerator, clutch
and brake pedals. Furthermore, the driver can retake control of the steering at
any time he or she wishes to do so and cancel the automatic parking manoeuvre.
This system accurately measures, with the help of side ultrasonic
sensors, the parking spaces and then carries out the manoeuvres to park the car
in the space, without the driver having to use the steering wheel.
Ford is currently developing a fully assisted automatic parking system.
This new system controls the steering, gear selection and forward and reverse
movements for parking. Therefore, the driver can be inside or outside the
vehicle during the parking manoeuvre.
This system requires a vehicle to have an automatic
gearbox, using a gearbox called Powershift, which is capable of electronically
controlling the forward and reverse gear changes without the physical
intervention of the driver.
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Powershift |