Automotive ionic and inductive sensors

1. Presentation about
“Automotive sensors”
Presented by Ibrahim Ezz
sery
Helwan university
https://www.facebook.com/

2. Ion sensors
 Ion Sensing is Measuring ionization current
generated from combustion through spark plug
electrodes.
 Extra measurement provided from the existing
ignition system, no added in cylinder
instrumentation .
 Electronics added to existing hardware Electronics
Directly reflects in--cylinder combustion process•
 Provides accurate misfire and knock detection.
intro

3. Ion sensor function
 Detecting knock in the engine.
 works without the use of a sensor.
 This method is new and is not typically used on a wider
scale in vehicle engines.
 This method requires a spark plug.

4. Ion sensor theory
•. By applying an electrical current across a pair of
spark plugs during the ignition of an engine, a
change in the conduction of the voltage can be
used to measure the status of the combustion.

5. Ion sensor technology
 In an ion-sensing ignition system, the spark plug itself becomes a
sensor.The ignition control (IC) module applies a voltage of
about 100 to 400 volts DC across the spark plug gap after the
ignition event to sense the plasma inside the cylinder.

6. Ion sensor technology
 A DC voltage is applied across the spark plug gap after the plug
fires and the circuit can determine if the correct air–fuel ratio was
present in the cylinder and if knock occurred.

7. Ion sensor technology

8. Ion sensor technology

9. Inductive sensors
intro
•The inductive sensor,
“magnetic pickup sensor”,
during the operational work, as
result of inductive effect, in the
sensor’s coil is producing the
oscillating voltage, i.e. one kind
of sinusoidal waveform signal (∼
AC voltage).

10. Inductive sensors function
•When the trigger wheel with the
teeth passes in enough close
distance (G) to the pole pin of the
sensor, the magnetic field
surrounding the coil is changed.
As the result of the magnetic
field changes, in the coil a
voltage is induced, which is
proportional to the strength and
rate of change of the magnetic
field. One complete oscillation is
produced for each tooth that
passes beside to the sensor pole
pin.

11. Inductive sensor theory
• 1.Sensor housing.
2. Output signal wires
3. Coaxial coated
protection
4. Permanent magnet
5. Inductive coil
6. Pole pin
7. Trigger wheel
G. Air gap

12. Inductive sensor technology
•.The output voltage signal produced by the sensor is weak, i.e. low
energy level, so could easily be degraded by other external stronger
signals, such as the ignition system for example. For that reason, to
eliminate the external influences, the signal wires from the sensor to
the control unit are usually shielded with a coaxial coated wires type of
protection.

13. Inductive SensorTesting
 check resistance of the coil
between 500:1500 ohms.
 If the reading zero or infinite,
replace the sensor.
 In some extreme cases,
the lowest resistance can be about 200 ohms, as
well as in some cases, the highest resistance can
be up to 2.500 ohms.

14. Inductive SensorTesting
 size of the air gap (G) between the sensor and the
trigger wheel, G ≈ 0.8 – 1.5 mm (0.03 – 0.06 inch).
 Check the cleanliness of the sensor pin (sometimes may
have cumulated metal turnings).
 Check the continuity and condition of the wires,
connectors, terminals and the condition of the
shielding.
 Unplug the sensor ,check o/p AC voltage when cranking
the engine (for engine rpm sensors) or when a wheel is
rotated (for ABS wheel sensors) between 1:2V during
the engine cranking for example, at higher rpm, can
expected more. Also, this operation can be performed
and when the connector of the sensor is plugged in.

15. Questions
