A long car trip is very tiring and your legs get tired very quickly. For such cases, the cruise control was invented. The passive maintains a given speed, but you have to follow the movement, but the adaptive one will even stop your car when an obstacle appears.
On long journeys, it is tiresome to keep your foot on the gas pedal, fatigue sets in very quickly, and the joints begin to ache. When driving through traffic jams, an automatic transmission saves, but when driving in a straight line, cruise control will come in handy. This is a system capable of maintaining the speed set by the driver. A similar device - very primitive, was present on some Soviet trucks in the form of a second parking brake, which was connected to the accelerator cable. And the first Soviet car equipped with a full-fledged solenoid system is the GAZ-21.
Passive cruise control
This is perhaps the simplest system. It consists of a control unit and actuators. The control buttons, and there are five of them in total and they are displayed on the steering wheel for ease of control, are used to switch operating modes. All of them, of course, are signed in English. List of buttons and their functions:
- the On button is used to turn on the cruise control system;
- Off - to turn off the system;
- the Set / Accel button will help you fix the speed with which you are currently driving, if you press it again, the speed will increase by two kilometers per hour;
- when the Coast button is pressed, the driving speed is reduced;
-and the Resume button is necessary to restore the speed that was set before braking.
It should be borne in mind that after pressing the brake pedal, the cruise control is deactivated. Therefore, you will need to either restore the previously set value using the corresponding button, or set a new one.
Cruise control is controlled by a special computer that reads some important parameters from the car's ECU (distance traveled, acceleration). And it doesn't matter whether you are moving uphill or descending from it, the speed will be maintained at the specified level. Also, the workload of the car does not matter.
Adaptive cruise control system
This is a more modern development, used on expensive cars. The on-board computer is able to maintain a given speed, as in the case of a passive system. It can also slow down when an obstacle appears in front of the vehicle. And if there is a wall in front of you, then the system will generally drop the speed to zero. Obstacle recognition occurs at a distance of up to 150 meters, and this is enough to make the right decision.
Determination of the distance to the vehicle in front is carried out using lidars and radars. The former are installed on cheap car models, since the cost of a lidar is much less than that of a radar. But the latter are used on all premium cars. In addition, lidars are very sensitive to atmospheric precipitation, failing during snow and rain. Radars do not have this feature.
But the principle of operation is the same for them. A sensor located in the bumper (sometimes behind the grille) emits a signal. When an obstacle appears, this signal is returned back. After calculating the time it took for the signal to return, the computer determines the distance to the obstacle. The frequency of the signal can be used to judge the speed of the vehicle in front. The adaptive system is connected not only with the power supply system, but also with the braking system. If necessary, the pressure in the brake cylinders increases, as a result of which the vehicle stops or decelerates.
