ATE wheel speed sensors

2

Why ATE wheel speed sensors?

Growing trend to comfort and safety: ABS is the standard today in all cars newly registered in Europe; ESP is well on its way to becoming the standard.

Transmission of information to control units, as in electronic brake systems (EBS), or TCS, EDL and ESP.

Precision an absolute must: wheel sensors are the most heavily stressed components of the brake control system.

They prevent the wheels from spinning and ensure proper roadholding.

Rapid and exact data capture for the operation of electronic control systems in vehicles: vehicle stability systems, engine management and transmission controls.

3

Passive sensor with sensor gear Active sensor with encoder wheel

Registers speeds from 3 km/h.

Passive sensors function according to the induction principle.

The output signal has AC voltage.

Registers speeds from 0 km/h.

Active sensors are digital sensors which work according to the magnetoresistive or Hall principle.

They must be supplied with current.

Difference between active and passive ATE wheel sensors

In the early days of ABS systems it was enough for the wheel sensors to supply a usable sensor signal at about seven km/h.

Due to the extension of ABS to included TCS, EDL and ESP functions, today it is necessary to develop sensor systems that supply a usable signal at very low speeds.

4

Features and functions of active ATE wheel sensors

Speed detection is based on the anisotropic magnetoresistive (A M R) effect. With this, and owing to integrated information processing, active sensors offer functions extending far beyond simple rotational speed detection. In the latest sensor generation these functions include:

Recognition of direction of rotation

Detection of stoppage

Additional digital input on sensor for external signals (e.g. brake pad wear monitoring)

Gap monitoring

Gaps as large as 4.5 mm

Standardized VDA data protocol

Current interface

5

Speed detection in the vehicle

2 Engine speed

3 Transmission speed

1 Wheel speed

Combination of wheel bearing with encoder track and active wheel sensor

23

1

6

Branded product - Profit from long experience. Continental Teves as world market leader has manufactured around 100 million active wheel speed sensors through today.

Wheel speed sensors thus make an active contribution to:

• High driving safety

• Higher driving dynamics

• Better ride comfort

• Lower fuel consumption

• Low emissions

Wheel sensors have been specially developed for your vehicle and verified in vehicle tests.

Exact calculation of the controlling action of ABS and ESP.

Tools / testing material in product range.

Advantages of active ATE wheel sensors

7

Original ATE wheel sensors - Service

Our wheel sensors are available everywhere in Europe in the small car segment, for older and newer vehicles.

A comprehensive parts range covering all makes is available to garage customers for professional repair of brake systems.

Apart from active wheel sensors the ATE product range includes passive wheel sensors.

Special ABS/ESP courses are a part of ATE's offer of training.

Suitable measuring equipment and tools are available for perfect fault diagnosis & repair.

On request a troubleshooting chart is available. It can be downloaded in the Internet.

ATE test card für magnetic sensor wheels

ATE Sensor Tester AST – the 2nd generation

8

Pictures of typical active wheel sensors

Active sensor w/o cable

Active sensor with cable (1)

Active sensor with cable (2)

Active sensor integrated in wheel hub

9

History of ABS

1920: Automotive and aeronautic pioneer Gabriel Voisin uses a hydraulically functioning anti-lock device for the first time.

1936: Patent application for “a device to prevent the stalling of the wheels of a motor vehicle”(*1).

1969: Presentation of an electronically controlled anti-lock braking system at the International Auto Show (IAA) in Frankfurt am Main.

“However, ABS control did not attain its current quality until the late 1970s when digital, freely programmable electronics, robust because contactless wheel speed sensors, and fast-acting hydraulic control valves became available. These components permitted maintaining slip in the tire-roadway system always within the range of the maximum friction coefficient”(*2).

In 1978 “this first closed-loop brake control system made its breakthrough in large-scale production in Mercedes-Benz cars”(*3).

“In 1995 the electronic stability program ESP revolutionized safety technology in vehicle manufacture. With sensors to detect lateral acceleration, steering wheel angle, body yaw rate and wheel speed, this system computes the course desired by the driver and continuously compares it with the actual direction of vehicle motion”(*4).

*1 to *4: Quoted from Bremsenhandbuch – Grundlagen, Komponenten, Systeme Fahrdynamik,

incl. page 9