Abs control unit is looking at the voltage coming back from the sensor. These systems completely relay on the information transmitted from the wheel speed sensor. There are two different types of sensors a hall sensor and an inductive pick up. However, some types of speed sensors cannot respond to very low speeds for differentreasons. Both work in the same way and conform to the same specification. In the past decade, wheel speed sensors have been moving to inside or on the wheel bearing or hub unit. A sensor that operates and generates a usable signal without an additional supply voltage applied is called a passive sensor. In case of a steel wheel application, a magnet placed inside the sensor is needed. At this location, the wheel speed sensors are more accurate and often more protected from the elements. Wheel speed sensors in motor vehicles function, diagnosis. Bosch wheelspeed sensor circuits use hall technology, which incorporates the hallsensing element, signal amplifier and signal processing all on a single chip. The pole pin, surrounded by a winding, connects to a permanent magnet whose magnetic effect extends to the pole wheel.
Wheel speed sensors wss can be broken down into two main types. Operating principle the wheel speed sensors are positioned directly above the impulse wheel, which is connected to the wheel hub or drive shaft. Speed sensor that can sense a ferrous metal target and is ideal for use in all types of environments and user specifications. Wheel speed sensors are classified as either active or passive, depending on how they operate. This section contains a description of the types of wheel speed sensor that can. Based on this information, the brake slip and wheel deceleration or wheel acceleration can be derived. Wheel speed sensors active and passive know your parts. Those system measurement generates the signals which is operated for the electronic stabilization program, traction control or anti lock braking system. Pdf improving the response of a wheel speed sensor by using a. Options include hermetically sealed, cryogenic, high temperature, intrinsically safe and explosion proof. Wheel speed sensor for abs systems data sheet analog devices. This information is used to prevent the wheels from locking and determine when the wheels are spinning, taking appropriate control action to maintain the vehicles stability and steering responses.
Passive analog sensors with a sinusoidal output signal type df6. The sensor measures road wheel speed and direction. There are two basic types of wheel speed sensor, passive and active. In addition navigation system also uses this technology. If you are replacing a wheel bearing on a latemodel vehicle, you will be dealing with a wheel speed sensor. Wheel speed sensor n 2006 land rover range rover sporthse from chassisvin 6a924697 4. Early, variablereluctance wheel speed sensors were passive, and well discuss their oper. The information about the wheel speed is received by the control unit from the wheel speed sensors. The average wheel bearing job may require a scan tool, scope or meter to verify the operation of the sensor. The conventional passive sensor consists of a magnetic pin with fine copper wire wrapped around to create a magnetic field. Depending on the model of the abs braking system, the design of the brake disc and the type of pulse wheel can vary.
Types of speed sensors motion sensors speed sensing. This information is used for antilock brake abs, traction control tcs or vehicle stability asp system ecus to prevent the vehicles wheels from locking or spinning. Wheel speed sensor is type of sensor used for measuring the speed of the wheels, per unit time. Before checking it must be clear which kind of sensor is fitted. Before going in to the details of what is a sensor, what are the different types of sensors and applications of these different types of sensors, we will first take a look at a simple example of an automated system, which is possible because of sensors and many other components as well. There are 2 types of wheel speed sensor we supply, the older black resin type, and the newer threaded body type. At this location, the wheel speed sensors are more accurate and often more protected from the. There are two types of sensors found on todays vehicles, the passive and the active. These sensors are made up of an internal transistor, which is activated by the moving relcutor. The control systems for abs, tcs and esc determine the wheel speed based on signals sent by the wheel speed sensors.
It is used to inform the abs control module of rotational wheel speed. The main difference between the two is the mounting. The sensor output format is a current pulse from 7ma to 14ma. High resistance or an open circuit can be immediately detected. With the advent of automated driving aid, such as electronic abs, the sensor also provided wheel speed. In some designs, the active sensor uses a tone ring and a permanent magnet like the variablereluctance passive sensor. Passive and active wheel speed sensors can look similar, but their operation is dissimilar. Wheel speed sensors are a necessary abs component and sensor input.
Check and change abs and wheel speed sensors hella. The conventional passive sensor consists of a magnetic pin with fine copper wire wrapped around to. The active, magnetoresistive wheel speed sensor was designed to combat the weak low speed signal characteristics of passive sensors. What is more, the main reason why such sensors are not good at. Wheel speed sensor sensor technology metropolia confluence.
In relation to driving safety, wheel speed sensors are of particular importance and are. These are similar in operation to inductive camcrank sensors. The circuit is exposed to the changing magnetic field of the rotating encoder, which is either a multipole or a steel wheel. The classification may seem counterintuitive, but heres how it works. On average, these sensors have 12volts of sensor power. In addition to the more common vr sensors, msi also offers an inductive type speed sensor for applications where magnets, rather than ferrous metal, will be sensed. All thirdgeneration type wheel bearings are equipped with this technology, which requires the presence of 4 sensors per vehicle. The wheel speed sensor was initially used to replace the mechanical linkage from the road wheels to the speedometer, eliminating cable breakage and simplifying the gauge construction elimination all moving parts except for the needlespring assembly. Most vehicles in use today use two types of wheel speed sensors. All these and many other automation tasks are possible because of sensors.
852 1273 20 1256 1019 1467 682 580 1514 585 1037 179 1152 162 235 1079 1199 248 277 1266 1241 249 185 21 668 475 365 609 101 382 622 748