Principles and trends in modern car allarm and safety systems
An allarm system consists of one or more sensors that detct some danger or fault, a central unit that resceives signals from the sensors and some warning devices that transmit the information to the resceiver. This warning device can be a sirene, some light arrangemant or the warning can be transmitted to a telephne, a computer or an allarm central of a security company, the fire brigade or the police.
The bacic principle of making car allarms are the same as those for other allarm systems, but the sensor units and warning devices must be fitted for installation in a car.
Traditionally there have been saparate systems for burglar allarm, fire allarms, water leak alllarms, fuel leak allarms.
Such separate systems are still in sale and many car owner do not need more advanced systems.
However, modern advanced systems have one allarm central that takes signal form all sensors and from sensors of all kind. The central has an integrate computer that makes all logical deductions based on resceived signals and transmits the warning to approproate waening units over wire or wirelessly to sirens, lights, telephones, computers or dedicated emergency centrals.
Sefety units like firew estingushers or automatic door locks are typically operating independently using thir own sensors or trigger mechanisms so that they allwas react when physical triggers exceed certain tresholds.
However, asvanced central units can also communicate with advanced authomatic safety unit like fire estinguishers or authomatic door locks, and transmit signals to the resceiver telling what safty units that has been activated.
The resceiver can also transmit commands back to ask for more information or to activate security devices.
Also advanced central units can trigger advanced safty devices to act under the right conditions when the central unit deduces this to be necessary even though the sensors of the individual safety units have not detected an overpassing of the tresholds.
Modern car typically have a map and navigation system that is helping the driver for geographical orientation and navigation. Advansed systems of this kind can also communicate wirelessly with centrals so that the owner or a dedicated service unit allways can know where the car is and can manage the work of the driver centrally.
Modern advanced alarm systems can send the warnings through this wireless navigation cervice so that the central unit administrating the work of the car can resceive warnings and activate safty measures. Intergration of allarm and saftey system with such float management is mostly used by the police, fire brigades, military, ambulance or great companies. But such functinality will be steadily cheaper so that efverybody can use it.
Modern cars typically has a car computer or driving computer. The next logical advancement of car saftey systems is to integrate the allarm central functions in the car computer so that when you install a new car computer or a car computer is delivered as a part of a new car, you will also get a complete allarm and safety central.
the steering mechanisms of cars and other four-wheeled vehicles
Parts of the car's steering mechanism transmits the driver's movements of the steering wheel to control the wheels that the car is rolling on. Almost all cars today are direvtionally governed on the front wheels. Trucks with four axles is controlled generally in two of front axles. Early vehicles were controlled with the control stick, but today is steering wheels prevalent.
From the earliest time and still in use in most cars are mechanisms where the physical steering power originates from the movement of the divers's arms. Several mechanisms may give additional power, but most cars are set up such that the driver can steer the car only by own power if the servo mchanism fails. Systems where the driver only sends signals and all the steering power is derived from technical components exist, but are only in use for special purposes, for example for handicapped drivers or especially heavy cars.
Several manufacturers, including Saab, has in recent years featured with joysticks, but this has not come into production. Joystick in use as a special adaptation of cars for drivers with mobility impairment.
In addition to changing vehicle direction control also has several tasks. One is to protect the driver's comfort, by not transferring all the bumps in the road to the hands, but still convey what's happening on the substrate. Management should also be predictable, and custom car preparation. For the security of "ordinary people" are most street cars today set up to the board, meaning that the car has a natural tendency to make a turn with a larger radius than the front wheel's angle would indicate. The radius of the turn indicated by a certain turn angle on the steering wheel is based on pcychology, not on any psychological ratio.
Th exact way thet the steering reacts and the exact way that the driver feels the properties of the road through the steering is usually constructed according to the main use of the car. A car used for sport-like activities wil be set up in another way than a typical family car or a car meant to be used for commercial transport activities.
From the steering wheel is a steering shaft down to a control worm or tooth bar management. Steering column on modern cars are generally designed to tilt upward at frontal impacts to avoid spearing the driver guide. Since long deformable steering stems are required as security measures in most countries. Modern cars have also usually adjustable steering wheel position. Steering column goes through several joints.
Power steering helps the driver by reducing the power needed for the front wheels. As a rule, they hydraulic mechanism, but in recent years, several cars had electric power steering mechanisms. Examples are the Toyota Yaris and Volkswagen Golf.
Some standard dimensions in the steering geometry are camber, caster, sharpening, Ackermann Angle and bump-/roll-steer.
Four wheel steering has been tried, especially in the eighties, nineties and after 2000, but not gained any wide acceptance. Cars that had this system in a period are GMC Sierra (2002), Honda Prelude (1988), Mazda 626 (1988), Mitsubishi GTO and Nissan Skyline GT-R.