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Categories: AutomotiveCar Talk

VEHICLE SENSORS: FUNCTIONS AND TYPES

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Function

In a way,
Sensors are the sensory organs of the vehicle.
A fundamental component of electronic control systems,
They must record physical or chemical variables and convert them;
Into electrical signals.

TYPES OF SENSORS

In recent years,
There has been an explosion in the number of different types of sensors.
Many new types of sensors have been seen in particular in the area of safety
And convenience electronics. Essentially, sensors can be categorized as follows:

1. Position sensors (distance/angle sensors)

Position sensors are used to capture the position of

  • The throttle valve
  • From the accelerator or brake pedal
  • Concerning the steering angle,
  • Of the angle of tilt, etc.

SEE MORE:

The ultrasonic and radar sensors used to determine distances from
Obstacles for modern driver assist systems also belong in this category.

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.

Also, read – Difference Between Crankshaft And Camshaft

Yaw rate sensors also belong in this category. They detect the rotational movement of the vehicle about its own axis and are needed for ESP.

3. Acceleration sensors

Acceleration sensors record the acceleration of the car body and\
Are used in passive safety systems
(airbags, seat belt pre-tensioner, roll bars)
And driving stability systems such as ABS and ESP,
As well as in chassis control.

Also, read – ANTI-LOCK BRAKING SYSTEM (ABS): COMPONENTS, TYPES AND WORKING PRINCIPLE

4. Pressure sensors

Pressure sensors are used to capture a wide variety of pressures including

  • Suction or charging pressure,
  • Fuel pressure, brake pressure,
  • Tire pressure,
  • Hydraulic reservoir pressure (for ABS and power steering),
  • Refrigerant pressure (air conditioning system),
  • Modulation pressure (automatic transmission) and so on.

Also, read

5. 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,
  • Tire air temperature and so on.

6. Force and torque sensors

Force and torque sensors are used to measure forces such as

  • Pedal force,
  • Drive,
  • Brake and steering torque forces or
  • The weight of the occupants of a vehicle (for adaptive restraint systems).

7. Flow-meters

Flow-meters are used to capture the fuel requirement and the amount of air drawn in by the engine.

8. Gas sensors

Gas sensors capture the composition of the exhaust gas (oxygen sensor, NOx sensor) or detect hazardous substances in the fresh air supply.

Also, read – Fuel Injector Cleaning: Is It Truly Necessary For An Automobile?

EXAMPLES OF SENSORS FOR ENGINE CONTROL:

  • Pulse sensor, crankshaft

The crankshaft sensor captures the engine speed and the position of the crankshaft. The control unit uses these values to calculate the injection pulse and the ignition pulse.

  • Camshaft position

The camshaft sensor is located at the cylinder head and scans a ring gear at the camshaft. This information is used, 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.

  • Air mass meter

The air mass meter is installed between the air filter housing and the intake manifold.
It measures the air mass drawn in by the engine. This variable provides the basis for
Calculating the fuel quantity that must be supplied to the engine.

Intake air temperature/Outside temperature/Interior temperature

Air temperature sensors capture the temperature of the ambient air. The values measured are used to control various systems (For example– the air conditioning 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.

Coolant temperature

The coolant temperature sensor is screw-mounted in the cooling system. The gauge tip protrudes into the coolant and records its temperature. The control unit uses this value
To adapt the amount of fuel injected to the engine temperature.

Throttle position

Throttle valve sensors are attached to the throttle valve axle. They monitor the opening angle of the throttle valve. From the values, the engine electronics calculate the fuel
Quantity which is injected based on other factors.

Knock sensors

Knocking is an uncontrolled form of combustion in a petrol engine. As continuous knocking can damage the engine,
It must be checked and regulated.

Also, read – The Engine


The engine controls unit evaluates the voltage signals received from the
Knock sensor and regulates the ignition point in a range just below
What is known as the knock limit? Knock sensors are permanently monitored by the control unit.

Also, read

Intake pipe pressure

The intake pipe pressure sensor measures the intake pipe
Vacuum downstream of the throttle valve and forwards this value to the
Engine control unit as an electrical signal. This is combined with the value of the air
Temperature sensor so that the air mass drawn in can be calculated.

Oxygen sensors

The oxygen sensor measures the residual oxygen content in the
Exhaust gas to ensure an optimum combustion mixture at all times.
Depending on the type of sensor, a chemical element
(titanium dioxide/zirconium dioxide)
And the residual oxygen content of the exhaust gas bias a voltage,
Which is then used by the control unit as a measured variable.

EXAMPLES OF SENSORS FROM CAR BODY ELECTRONICS:

* Wheel speed

The wheel speed is used by driving safety systems such as
ABS and ASR as a speed value as well as
By GPS systems to calculate the distance traveled.
A fault will cause these systems to fail, significantly impairing safety.

* Speed, transmission

The transmission sensor captures the transmission speed.
The speed signal is used by the
Control unit for precision control of the shift pressure during shifting and
To decide which gear should be engaged when.

* Speed, distances traveled

Distance sensors are used to capture driving speed. They are mounted on the transmission or rear axle. The information obtained is required for the speedometer,
Cruise control, and converter slip control.

* 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 signal to the engine control unit
Which activates an indicator lamp.

* Brake lining wear

The brake wear sensors are located on the brake linings and
Are subject to the same wear. A visual signal tells the driver that the wear limit has been reached.

* 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 thus have a key role to play in increasing safety on our roads.

Some of the safety systems are

1. Forward collision avoidance system

This warns the driver when the car is in front of another vehicle.
RADAR or LIDAR to sense the objects or
Other vehicles in front of the vehicle.
A forward-collision warning system provided with
Autonomous braking can;
Reduce the speed of the vehicle thereby mitigating the effect of a collision.

2. Adaptive cruise control

The adaptive cruise control maintains the vehicle’s pre-set speed. It automatically slows
Down the vehicle in heavy traffic to maintain a safe gap. Forward-mounted sensors keep track of the distance to the vehicle at the front. The vehicle accelerates to maintain the
Preset cruise speed as the traffic speeds up.

3. Lane departure warning and prevention system

This system employs cameras to track the position of the vehicle within the lane and
Alert the driver if the vehicle is in danger. Certain systems offer haptic warnings such as
Seat or steering vibrations,
While others provide audible and/or visual warnings.

4. Blindspot detection system

This sensor network system monitors the blind spots at the front,
Side and rear areas of the vehicle. Most of the systems provide visual alerts appearing on
Or near the side-view mirrors upon detecting 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 may also activate the steering controls or
Brake to maintain the vehicle in its lane.

5. Park assist and backover prevention system –

Assists drivers to park and back up their vehicles.
Rear object detection systems make use of sensors and
Cameras to enable the driver to look for the objects in the rear side of the vehicle while backing up.

6. Adaptive headlight

It alerts drivers to visualize objects better on dark, curved roads. The headlight pivots in
The direction of a moving vehicle to illuminate the road ahead based on the vehicle’s
Speed and steering wheel movement.

7. Fatigue warning systems

It employs sophisticated algorithms to monitor the
Steering control and other behaviors
Such as blink duration and blink rate of the driver. This system is designed to warn the
Driver if it detects drowsiness or inattention.

8. Curve speed warning system

It monitors the vehicle as it approaches bends in the road
By using a global positioning system and a digital map. Curve speed sensors alert the
Driver if the system senses that the vehicle is nearing a curve at an over speed.

Also, read – How car electrical systems work

* Environmental protection

Sensors make modern vehicles not only safer but Also, cleaner.

They supply the basic information for clean and
Effective fuel combustion in the engine,
Thereby enabling exhaust emissions values and fuel consumption to be
Reduced significantly.

Eventually,
They support the reliable functioning of high-efficiency exhaust re-treatment systems. Examples include the controlled 3-way catalytic converter,
The diesel particulate filter or the DeNOx catalytic converter.

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