Types Of Vehicle Sensors And Their Functions
In a way, Vehicle sensors are the sensory organs of the vehicle. A elementary part of electronic management systems, they have to record physical or chemical variables and convert them into electrical signals…
TYPES OF VEHICLE SENSORS
In recent years, there has been an explosion in the number of different types of sensor. Many new sorts of sensing element are seen specially within the space of safety and convenience physical science.
Essentially, sensors can be categorised as follows:
1. Position sensors (distance/angle sensors) –
Position sensors are used to capture the position of the throttle valve, accelerator or brake pedal, gap and angular positions in diesel injection pumps, fill level in the fuel tank, steering angle and angle of tilt, etc.
The unhearable and measuring instrument sensors accustomed confirm distances from obstacles for contemporary driver assist systems conjointly belong during this class.
2. Speed and velocity sensors
Speed and velocity sensors are used to determine the speed of crankshafts, camshafts and diesel injection pumps or wheel speeds. Yaw rate sensors also belong in this category.
They notice the movement movement of the vehicle regarding its own axis and are required for clairvoyance.
3. Acceleration sensors
Acceleration sensors record the acceleration of the automobile body and are utilized in passive safety systems (airbags, seat belt tensioners, roll bars) and driving stability systems such as ABS and ESP, as well as in chassis control.
4. Temperature sensors
Temperature sensors are used to capture temperatures, e.g. in the context of measuring suction or charge air temperature, ambient and interior temperatures, evaporator temperature (air conditioning system), coolant temperature, engine oil temperature, tyre air temperature and so on.
4. Pressure sensors
Pressure sensors are used to capture a wide variety of pressures including suction or charging pressure, fuel pressure, brake pressure, tyre pressure, hydraulic reservoir pressure (for ABS and power steering), refrigerant pressure (air conditioning system), modulation pressure (automatic transmission) and so on.
5. Force and torque sensors
Force and torsion sensors are to measure forces like pedal force, drive, brake and steering torque forces or the burden of the occupants of a vehicle (for reconciling restraint systems).
6. Flow-meters
Flow-meters are to capture the fuel demand and therefore the quantity of air drawn in by the engine.
7. Gas sensors
Gas sensing elements capture the composition of the exhaust gas (oxygen sensor, NOx sensor) or detect hazardous substances in the fresh air supply.
EXAMPLES OF VEHICLE SENSORS FOR ENGINE CONTROL:
A) Pulse sensor-
The crankshaft sensor captures the engine speed and the position of the crankshaft.
The management unit uses these values to calculate the injection pulse and therefore the ignition pulse.
B) Camshaft position-
The rotating shaft sensing element is found at the plate and scans a hoop gear at the rotating shaft.
This data is employed, for example, for the start of injection, for the signal to activate the solenoid valve for the pump/nozzle injection system and for cylinder-specific knock control.
C) Air mass meter-
The atmospheric state meter is put in between the air cleaner housing and therefore the manifold. It measures the atmospheric state drawn in by the engine.
This variable provides the premise for shrewd the fuel amount that has got to be equipped to the engine.
D) Intake air temperature/Outside temperature/Interior temperature-
Air temperature sensors capture the temperature of the ambient air. The values measured are to management varied systems (e.g. the air con system) or as correction values for the injection system.
The installation location is determined by the air temperature to be measured. The sensor for the intake air temperature, for example, is located in the air duct for the intake air.
E) Coolant temperature-
The fluid temperature sensing element is screw-mounted within the cooling system. The gauge tip protrudes into the fluid and records its temperature.
The management unit uses this worth to adapt the number of fuel injected to the engine temperature.
F) Throttle position-
Throttle valve sensors are connected to the valve shaft. They monitor the gap angle of the valve.
From the values, the engine electronics calculates the fuel quantity which is injected based on other factors.
G) Knock sensors-
Knocking is an uncontrolled form of combustion in a petrol engine. As continuous knock will injury the engine, it should be checked and controlled.
The engine management unit evaluates the voltage signals received from the knock sensing element and regulates the ignition purpose during a vary slightly below what’s called the knock limit.
Knock sensors are for good monitored by the management unit.
H) Intake pipe pressure-
The intake pipe pressure sensing element measures the intake pipe vacuum downstream of the valve associate degreed forwards this worth to the engine management unit as an electrical signal.
This is combined with the worth of the air temperature sensing element in order that the atmospheric state drawn in will be calculated.
I) Oxygen sensors-
The oxygen sensor measures the residual oxygen content in the exhaust gas in order to ensure an optimum combustion mixture at all times.
Depending on the kind of sensing element, a substance (titanium dioxide/zirconium dioxide) and therefore the residual gas content of the exhaust gas bias a voltage, that is then utilized by the control unit as a measured variable.
EXAMPLES OF VEHICLE SENSORS FROM CAR BODY ELECTRONICS:
A) Wheel speed
The wheel speed is employed by driving safety systems like ABS and ASR as a speed worth similarly as by GPS systems to calculate distance traveled.
A fault can cause these systems to fail, considerably impairing safety.
B) Speed, transmission
The transmission sensor captures the transmission speed.
The speed signal is employed by the management unit for preciseness management of the shift pressure throughout shifting and to make a decision that gear ought to be engaged once.
C) Speed, distances travelled
Distance sensors are used to capture driving speed. They are mounted on the transmission or rear shaft.
They info obtained is needed for the speed indicator, cruise control and converter slip control.
D) Engine oil level/Coolant level
For reasons of operational safety and for increased comfort, levels such as engine oil, coolant and washer fluid are monitored with level sensors.
The level sensors send a proof to the engine management unit that activates associate degree indicator.
E) Brake lining wear
The brake wear sensors square measure set on the brake linings and square measure subject to an equivalent wear.
A visual signal tells the driving force that the damage limit has been reached.
F) Safety
The sensor information provides the basis for the function of numerous active and passive safety systems. Thanks to significant progress in the development of new sensors, there has been a constant increase in the capabilities of safety and driver assist systems in recent years.
Sensors therefore have a key role to play in increasing safety on our roads.
Some of the safety systems are:-
Forward collision avoidance system –
It alerts the driving force once the vehicle is obtaining on the point of another vehicle ahead of it. It employs varied sensors like cameras, RADAR or LIDAR to sense the objects or other vehicles in front of the vehicle.
A forward collision warning system supplied with autonomous braking will scale back the speed of the vehicle thereby mitigating the impact of collision.
Adaptive cruise control –
Adaptive cruise control maintains the vehicle’s pre-set speed. It mechanically slows down the vehicle in serious traffic to take care of a secure gap.
Forward-mounted sensors keep track of the space to the vehicle at the front. The vehicle accelerates to take care of the planned cruise speed because the traffic hastens.
Lane departure warning and prevention system –
This system employs cameras to trace the position of the vehicle at intervals the lane and alert the driving force if the vehicle is at risk.
Certain systems provide somatosense warnings like seat or steering vibrations, while others provide audible and/or visual warnings.
Blind spot detection system –
This detector network system monitors the blind spots at the front, side and rear areas of the vehicle. Most of the systems offer visual alerts showing on or close to the view mirrors upon police investigation the blind spot.
An audible alert is activated when the driver signals a turn, and the vehicle is headed towards the blind spot on the turning side. Certain systems might also activate the steering controls or brake to take care of the vehicle in its lane.
Park assist and backover prevention system –
Assists drivers to park and make a copy their vehicles.
Rear object detection systems build use of sensors and cameras to alter the driving force to appear for the objects within the rear facet of the vehicle whereas backing up.
Adaptive headlight
it alert drivers to see objects higher on dark, curved roads.
The headlamp pivots within the direction of a moving vehicle to illuminate the road ahead supported the vehicle’s speed and wheel movement.
Fatigue warning systems
it use refined algorithms to observe the steering management and different behaviors like blink length and blink rate of the driving force.
This system is intended to warn the driving force if it detects sleepiness or basic cognitive process.
Curve speed warning system
it monitors the vehicle because it approaches bends within the road by employing a international positioning system and digital map.
Curve speed sensors alerts the driving force if the system senses that the vehicle is nearing a curve at associate degree over speed.
Environmental protection
Sensors build fashionable vehicles not solely safer however additionally cleaner.
They supply the fundamental info for clean and effective fuel combustion within the engine, thereby enabling exhaust emissions values and fuel consumption to be reduced significantly.
Finally, they support the reliable functioning of high-efficiency exhaust re-treatment systems.
Examples embody the controlled 3-way convertor, the diesel particulate filter or the DeNOx convertor.
