4. • Modern cars have become a complex piece of machinery
when compared to vehicles a couple of decades ago. A
modern-day car comprises several electrical components as
mechanical parts are getting replaced or aided by electronic
devices. One such crucial electrical component of an
automobile is the sensor. In this article, we throw light on
different types of sensors in a car and their functions.
• What is a car sensor?
A car sensor is an electronic device that monitors various
aspects of the vehicle and sends information to the driver or
ECU (Electronic Control Unit). In certain situations, the ECU
automatically makes adjustments to the particular component
based on the information received from the sensor. The below
points cover more details about car sensors.
5. Functions of automotive car sensor
• The working principle of a sensor gives you a broad idea of
the functions of car sensors. Since there are so many
sensors in a car monitoring various systems and working of
components, the functions of car sensors are broader than
you imagine
How many sensors does a car have?
The car engine alone has around 15 to 30 sensors that track all
functions of the engine. In total, a car can have over 70 sensors
that monitor various aspects of the vehicle.
Do all types of cars have sensors?
Yes, all types of cars have sensors. From a small hatchback to
a large SUV (Sports Utility Vehicle), all vehicles come equipped
with sensors for the efficient functioning of the engine and other
components.
6.
7. • A speed sensor is a
type of position sensor
which is used to
measure rotational
speed. They are
present in various
types of commercial
and motorsport
vehicles. Like many
devices, a speed
sensor is an integral
part of onboard
Speed Sensor
8.
9. Camshaft position sensor
The camshaft position sensor is
an electronic sensor used to
determine the exact position of
the engine’s camshaft and
converts it into an electronic
signal then sends it to the car
ECU. It determines the location
of the camshaft and its angle in
order to determine the position
of the engine cylinder’s piston to
be operated.
10. Types of Camshaft Position Sensor
Magnetic Type Sensor:
The magnetic type
camshaft position sensor is
recognized by the two
wires that it contains. This
generates its own voltage,
an alternating current
(AC) sine wave signal. It
can be located inside
the distributor or on the
camshaft.
11. Hall Effect Sensor:
Whereas this type of camshaft
sensor has three wires. The first
wire is for its reference power, the
second for its ground, and the third
for the signal voltage to be sent to
the computer. The Hall Effect
sensor is also located inside the
distributor or on the camshaft.
12. A.C. Output Sensor:
These are special types of camshaft
position sensors that generate an
AC voltage signal as an output. The
ECM generates a very high
frequency (150 to 2500 cycles) for
the exciter coil, which is located
near the rotating disc.
15. What is an Oxygen sensor ?
An oxygen sensor or lambda sensor is an electronic device that
measures the proportion of oxygen (O2) in the gas or liquid being
analysed.
16. Function of oxygen sensor
The oxygen sensor senses the
amount of oxygen in the vehicle’s
exhaust. It is usually located in the
exhaust pipe. The oxygen sensor
reading is used by the Engine
Control Unit (ECU) to regulate the
amount of air and fuel sent to the
engine. It helps maintain the
perfect air-fuel ratio, thereby
preventing the engine from running
lean/rich; it also reduces the
exhaust emissions.one end of the
oxygen sensor detects the amount
of oxygen while the other end
connects to wiring that relays the
sensor reading to ECU
17. Heated and Non-heated oxygen
sensor
A one wire or two wire unheated
oxygen sensor is the earliest and
most basic type of sensor. One
wire sensors employ only a signal
wire, while two wire versions also
have a wire going to ground.
Unheated sensors require
external heat and thus can only
be located close to the engine’s
exhaust ports, which are not ideal
locations in which to measure A/F
ratio. Another limitation of the
unheated sensor is that it can
take a minute or longer to reach
the temperature required for
proper operation.
Non-heated oxygen sensor
18. Heated and Non-heated oxygen
sensor
Heated oxygen sensor Three and four wire heated oxygen
sensors evolved in order to reach
operational temperature more
rapidly.
The heater element is an internal
resistor that heats up as via an
electrical current that is passed
through it. Heated sensors can be
placed in downstream locations on
the exhaust system and will stay at
the proper temperature for a longer
period of time than unheated
sensors.
All modern oxygen sensors employ
a heater, though the type and heat-
up times vary.
19. Upstream and downstream sensors
The upstream sensor
monitors the level of
pollutants in the engine’s
exhaust and sends this
information to the ECU
that continuously adjusts
the air-fuel ratio.
The downstream sensor
measures the level of
pollutants passing
through the catalytic
converter.
The information of
upstream and
downstream sensors are
compared by the ECU.
20. When to Replace the Oxygen Sensor
the oxygen
sensor should
be replaced
every 60,000 to
90,000 miles.
This sensor
does wear out
and will need
replacement
over time.
21. Advantages of the oxygen sensor
1. It helps the vehicle to control fuel economy
2. It helps in the smooth running and performance of the engine
3. It also helps to monitor the vehicle's catalytic converter
thereby saving our atmosphere a lot less of pollution
22.
23. Air-flow sensor
It is a type of sensor that measures the volume and density of air entering
the engine.
It is placed inside the combustion chamber.
It ensures the right amount of air-fuel mixture enters the combustion
chamber for optimum performance.
Failure of the air-flow sensor can result in engine stalling or more fuel
consumption.
26. Parking sensor
• Definiton :
Parking sensors are proximity sensors for road
vehicles designed to alert the driver of obstacles
while parking. These systems use either
electromagnetic or ultrasonic sensors
27. So what is electromagnetic or
ultrasonic sensors ?
Parking sensor
Electromagnetic systems
Ultrasonic systems
These systems feature
ultrasonic proximity
detectors to measure the
distances to
nearby objects via sensors
located in the front and/or
rear bumper fascias or
visually minimized within
adjacent grills or recesses.
These systems feature
ultrasonic proximity detectors
to measure the distances to
nearby objects via sensors
located in the front and/or rear
bumper fascias or
visually minimized within
adjacent grills or recesses.
28.
29. MANIFOLD ABSOLUTE PRESSURE SENSOR (MAP SENSOR)
The Manifold Absolute Pressure
(MAP) sensor is used to convert the
manifold pressure into an electrical
signal for the ECU(electronic
control unit) to use. MAP sensors
are frequently used in engines
that inject fuel. The manifold
pressure sensor transmits real-time
manifold pressure data to the
engine's electronic control unit
(ECU). The function of data is to
calculate the air density and
determine the engine's air mass
flow rate, determining the fuel
metering required for optimal
combustion and influencing the
ignition timing advance or
retardation. In order to detect
intake airflow, fuel-injected engines
may use a mass airflow sensor
(MAF sensor).
30. •With analog output:
Widely used. Its voltage
is proportional to the
engine load.
• TYPE OF MANIFOLD ABSOLUTE PRESSURE SENSOR (MAP SENSOR)
•With a digital
output:
it is used in
systems such as the
Ford EEC IV.
33. What is a Nox sensor
?
NOx sensor or
a nitrogen oxide
sensor is typically a
high-temperature
device built to
detect nitrogen
oxides in combustion
environments such as
an automobile,
truck tailpipe or smok
estack. They’re a
small but important
part of a diesel after
treatment system.
34. How does a NOx sensor work?
When the nitrogen oxide
sensor detects excessive
nitrogen oxide or ammonia
at a specific temperature
with the Selective Catalytic
Reduction (SCR) outlet, a
fault code will be triggered
as a catalyst through the
on-board diagnostics and
an alert will appear in a
display visible to the driver.
35. Where is the NOx sensor
located?
The location of the
nitrogen oxide sensor is
typically installed Pre and
Post the SCR Filter, which
is normally the last part of
the after-treatment system.
The upstream nitrogen
oxide component location
and downstream nitrogen
oxide sensor location is
going to be different
depending on the truck.
36. How Do You Know If Your NOx
Sensors Are Faulty?
37. How Do You Know If Your NOx
Sensors Are Faulty?
The NOx sensors tells the ECU how much DEF should be injected
into the exhaust before it enters the SCR. If the sensors are faulty,
you’ll likely see increased DEF consumption and fuel spending,
alongside erratic or unstable idling. At this point, your truck is likely
to throw a fault code, and trigger a warning light on your
dashboard.
The mosa bad NOx sent common fault codes
associated with sor are :
SPN 3217 FMI 3 (SCR inlet NOx sensor circuit, failed high)
SPN 3217 FMI 5 (SCR inlet NOx sensor circuit, failed open)
SPN 3227 FMI 3 (SCR outlet NOx sensor circuit, failed high)
38. Can You Drive with A Bad NOx
Sensor?
It’s important to repair or replace a faulty NOx sensor quickly
to protect your engine and aftertreatment system. You can
drive for a short time with a faulty one, with the engine
running rich and over-using DEF, but the ECU will eventually
send your truck into limp mode and engine derate.
39.
40. Engine knock sensor
Knocking is a phenomenon where the air-fuel mixture ignites before the
spark plugs produce the spark.
It reduces engine efficiency, and in the longer run, it can cause damage
to the engine components.
The engine knock sensor detects knocking by monitoring the air-fuel
mixture ignition process.
The sensor can warn the driver if there is any fault in the ignition of the
air-fuel mixture.
41. • The knock sensor is located on the outside of the
engine block. It is intended to record knocking noise in
all engine operating states in order to prevent engine
damage.
42.
43. car rain sensor
Rain sensor definition :
The rain sensor is a driving assistance device
designed to promote driver comfort when
driving, by automatically activating the wiper
blades at the appropriate frequency when the
system detects the presence of raindrops on the
windshield.
Introduction to the rain sensor
The rain sensor, also called rain detector, is a small electronic device
that appeared in motor vehicles during the 1990s. Installed at the base
of the interior mirror, this device is directed outwards, which allows it to
capture the state of weather conditions and their impact on the
windshield of the automobile, while not interfering with the driver's
field of vision
44. car rain sensor
Operation of the rain sensor
Generally coupled with the brightness
detector, the rain sensor makes it possible
to detect the presence of precipitation on
the windshield of an automobile thanks to
a measurement of the brightness that can
be carried out using infrared technology.
45. car rain sensor
Infrared rain sensors
Infrared rain sensors incorporate a light-emitting diode, refractive prism and
photodiodes. In dry weather, the light ray generated by the light-emitting diode will
pass through the prism, then will be deflected by the windshield before touching the
receiver diode. In rainy weather, however, the ray generated by the diode will not
be entirely reflected by the windscreen, but will be deflected by the raindrops. In
this case, the receiver diode will see that it is no longer receiving enough light, and
a computer will send an electrical signal in order to order the vehicle's windscreen
wiper blades to activate, and will even select the beat speed of the equipment in
order to optimize the evacuation of the rain
46. Throttle position sensor
A throttle position sensor
(TPS) is a sensor used to
monitor the air intake of an
engine. The sensor is usually
located on the butterfly
spindle/shaft, so that it can
directly monitor the position
of the throttle. More
advanced forms of the
sensor are also used.
47. types of a Throttle position sensor
TPS Variable Resistor
model:
This variable resistor
model TPS uses a
resistor as a change in
the magnitude of the
sensor output voltage
signal, this sensor uses
three cables, namely the
input voltage cable (VC)
48. TPS Contact Point Model:
This point contact model TPS
sensor serves to detect
changes in gas throttle
openings and the terminals
used on the point-contact
type TPS sensor are also the
same as the variable resistor
type TPS sensor, namely by
using three wires including
IDL, PSW, and E1 terminals
51. What is an Temperature Sensor ?
A fuel temperature sensor is installed in vehicles to
gauge the amount of fuel required for consistent
performance. The sensor transmits this information to
the Engine Control Unit (ECU) of the vehicle.
The fuel of a car is affected significantly if the fuel
teeconomymperature sensor goes bad.
52. WORKING PRICIPLE
The fuel rail sensor, also known as
the fuel pressure sensor, is an
engine management component
found on diesel and some gasoline-
injected vehicles. It is a component
of the vehicle’s fuel system that is
used to monitor the fuel pressure at
the fuel rail. This signal is sent by
the sensor to the computer, which
then uses it to adjust the vehicle’s
fuel and timing. When there is a
problem with the sensor, it can
affect the vehicle’s performance
54. What happens if a fuel temperature
sensor fails?
1. Difficult start
2. Loss of power, acceleration, and fuel
efficiency.
3. The Check Engine Light
illuminates
55. Causes of a problematic fuel
temperature sensor:
• A programming issue in the powertrain control
module.
• Unfortunate ambient temperature sensor.
• Minor or major faults in the fuel temperature senso
• Open or damaged wiring or connectors.
56. Engine speed sensor
It is a sensor that monitors the speed and position of the crankshaft.
The sensor is fitted to the crankshaft.
It detects the crankshaft position and relays the information to the ECU.
The ECU then calculates the exact time for fuel injection and activate the
spark plugs.
If the timing is not correct, the engine loses its efficiency.
It is one of the most important sensors in a car.
60. What is an Temperature Sensor ?
A coolant temperature
sensor is confined to the
engine of a vehicle and
measures the temperature of
the vehicle’s engine coolant.
The sensor feeds this
information back in the form
of an electrical current to the
engine control unit (ECU).
The ECU then responds to a
change in the temperature
difference and readjusts the
engine’s fuel injection.
61. How Does a Coolant Temperature
Sensor Work?
A coolant sensor, or
car temperature
sensor, is similar to
a thermistor; it is
based on the
working principle
that a change in
electrical resistance
will be the direct
product of a change
in the temperature
of a wire carrying
current.
62.
63. fuel level sensor
A fuel level sensor
is used to monitor,
maintain, and
measure the level
of fuel in a vehicle.
After detecting the
fuel level, the
sensor turns the
observed data into
electronic signals.
64. Types of Fuel Level Sensors
Digital Output Interface Sensor :
Digital Sensor provides the
output in a range of discrete
values over RS232 or RS485
outputs. It keeps on changing
as the fuel is consumed and
the level of the fuel in the
vehicle is changed
Bluetooth Output Interface Sensor :
It is fully wireless, has no wires, and
communicates over Bluetooth with the
supported Telematics Unit.
Analog Output Interface Sensor
The sensor essentially
provides the variating voltage
output at the sensor terminals
while the vehicle moves and
starts consuming the fuel.
65.
66. Conclusion: Advantages and disadvantages of car
sensors
• Below are the advantages of car sensors.
Car sensors make driving an easy task.
The sensors can easily detect faulty components in a vehicle.
Sensors ensure that the engine is maintained correctly.
Sensors also enable automatic control of specific functions such as windscreen wipers,
headlights, etc.
The ECU can make precise adjustments with the information received from sensors.
Sensors can also relay warning information to the driver if there is any fault/malfunction with
the car’s components.
• Here are some of the disadvantages of car sensors.
One major disadvantage of having so many sensors on board is that they can fail over time.
A faulty sensor can lead to damage to vital components of the vehicle. Getting them repaired
or replaced can be an expensive affair.
