Motor Vehicle Level 3
This presentation is the property of its rightful owner.
Sponsored Links
1 / 18

Motor Vehicle Level 3 PowerPoint PPT Presentation


  • 69 Views
  • Uploaded on
  • Presentation posted in: General

Motor Vehicle Level 3. Resource 4. ABS Sensors Their Operation and Waveform Produced. Motor Vehicle Level 3 Resource 4. ABS Sensors Their Operation and Waveform Produced. Aims. To recognize various sensors used within ABS systems and their role within the system.

Download Presentation

Motor Vehicle Level 3

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


Motor vehicle level 3

Motor Vehicle Level 3

Resource 4

ABS Sensors Their Operation and Waveform Produced


Motor vehicle level 3

Motor Vehicle Level 3Resource 4

ABS Sensors Their Operation and Waveform Produced

Aims

To recognize various sensors used within ABS systems and their role within the system


Motor vehicle level 3

Motor Vehicle Level 3Resource 4

ABS Sensors Their Operation and Waveform Produced

Objectives

By the end of this session you will be able to:

  • Identify various sensors including hall, and be able to describe passive and inductive sensors and their operation

  • Recognize the role of the speed sensor and it's location

  • Recognize and comment on the waveforms produced.

  • Comment briefly on how to maintain the sensor, and identify possible faults.


Motor vehicle level 3

Motor Vehicle Level 3Resource 4

ABS Sensors Their Operation and Waveform Produced

Types of sensor : Active Sensor

  • Example:-Magnetised pick up (crankshaft sensor, ABS sensor)

  • Voltage signal produced is sent to the input of the ECU for analysation.

  • The ECU will covert this Analogue signal to Digital signal which the ECU can read.

  • The ECU will now react (alter the brake pressure depending on this voltage signal.


Motor vehicle level 3

Motor Vehicle Level 3Resource 4

ABS Sensors Their Operation and Waveform Produced

Types of sensor : Passive Sensor (three wire)

  • Three wire device

  • Supply voltage for the sensor is supplied via the ECU

  • The internal resistance alters with a change in environment these are usually used to sense movement (i.e. throttle position)

  • This is measured by the ECU and the ECU will alter accordingly


Motor vehicle level 3

Motor Vehicle Level 3Resource 4

ABS Sensors Their Operation and Waveform Produced

Types of sensor : Passive Sensor (two wire device)

  • Similar to a three wire device, the sensors internal resistance will alter with a change in environment rather than change in movement (i.e. engine coolant)

  • ECU Supplies voltage to the sensor,

  • The ECU will measure the change in internal resistance and react accordingly.


Motor vehicle level 3

Motor Vehicle Level 3Resource 4

ABS Sensors Their Operation and Waveform Produced

ABS Sensors

  • Of course, ABS will use an active sensor

  • Why do you think that is?

  • Could it use a passive sensor?


Motor vehicle level 3

Motor Vehicle Level 3Resource 4

ABS Sensors Their Operation and Waveform Produced

ABS Wheel Speed Sensor

  • Wheel Speed Sensors are mounted at each wheel and sends a rotation signal to the ECU

  • Wheel speed sensors can be mounted to the steering knuckle or to the axle carrier


Motor vehicle level 3

Motor Vehicle Level 3Resource 4

ABS Sensors Their Operation and Waveform Produced

ABS Wheel Speed Sensor


Motor vehicle level 3

Motor Vehicle Level 3Resource 4

ABS Sensors Their Operation and Waveform Produced

ABS Wheel Speed Sensor

  • As the teeth of the sensor rotor pass the iron core, magnetism will cut through the coil windings Inducing a voltage

  • When the tooth is centered to the iron core 0v is produced

  • As the tooth moves away from the iron core, the magnetic field expands producing a negative voltage

  • As the wheel rotates faster the voltage and frequency increase (indicating to the ECU that the vehicle is travelling faster)


Motor vehicle level 3

Motor Vehicle Level 3Resource 4

ABS Sensors Their Operation and Waveform Produced

Waveform produced

  • In order to diagnose a fault within an ABS system waveforms are useful in order to determine system performance, and will also give hints as to the problem.


Motor vehicle level 3

Motor Vehicle Level 3Resource 4

ABS Sensors Their Operation and Waveform Produced

Waveform produced

  • The following images where taking using a diagnostic tool called a Picoscope

  • These show two wheel speed sensors being monitored, one has a fault...is it the red trace or the blue trace?


Motor vehicle level 3

Motor Vehicle Level 3Resource 4

ABS Sensors Their Operation and Waveform Produced

Waveform produced


Motor vehicle level 3

Motor Vehicle Level 3Resource 4

ABS Sensors Their Operation and Waveform Produced

Waveform produced

  • this small capture taken from the waveform produced indicates a fault compared with the blue trace

  • The fact the we have a waveform at all indicates that the sensor is producing a signal.

  • Therefore, we can diagnose that the rotor wheel has failed.


Motor vehicle level 3

Motor Vehicle Level 3Resource 4

ABS Sensors Their Operation and Waveform Produced

Waveform produced

  • This vehicle measures rear wheel speed via a driveshaft, upon inspection, we can see that the teeth have been damaged, furthermore, we can see this corresponds to our waveform produced.

  • Another factor that could have produced a similar waveform could have been distance from the sensor to the rotor or contamination of the sensor.


Motor vehicle level 3

Motor Vehicle Level 3Resource 4

ABS Sensors Their Operation and Waveform Produced

Waveform produced

  • In order to check the voltage is correct to the sensor

  • Ensure that your multimeter is correct and on the correct function (direct v)

  • Measure between the terminals as shown (always refer to manufactures guidelines)

  • The voltage should be between 10v-14v


Motor vehicle level 3

Motor Vehicle Level 3Resource 4

ABS Sensors Their Operation and Waveform Produced

Probing a Sensor

  • Continuity check

  • Is done to check that there is no faults in the wiring harness between the ECU, the Actuator and the ABS relays and possibly to the sensors.

  • Refer to manufactures guidelines

  • From the signal contact in the terminal blocks check the resistance between each components.

  • The resistance should be around 4-6ÎŹ


Motor vehicle level 3

Motor Vehicle Level 3Resource 4

ABS Sensors Their Operation and Waveform Produced

Summary

Have We:-

  • Identified various sensors including hall, and be able to describe passive and inductive sensors and their operation

  • Recognized the role of the speed sensor and it's location

  • Recognized and commented on the waveforms produced.

  • Commented briefly on how to maintain the sensor, and identify possible faults.


  • Login