Brake pedal sensor

Ensure the safety and braking efficiency of electric vehicles

The multiplication of electric motorizations implies new needs such as the brake pedal sensor. This is an essential element to ensure efficient and safe braking of electric or hybrid vehicles.

Driven by regulatory and technological developments, car manufacturers are multiplying electric or hybrid vehicle projects. EFI Automotive has developed a brake pedal sensor (Brake Pedal Sensor) specifically dedicated to these new engines: “The sensor measures the pedal angle” explains Kevin Hertrich, Vehicle dynamics & new functions Market Manager, “and based on this angle, will collect information that will distribute the vehicle’s braking rather towards mechanical braking if the angle is significant or towards the electric motor’s engine brake if it is not significant“. The electric motor brake is preferred to recover energy and increase vehicle range, which is a crucial issue for electric vehicles.

The extreme need for accurate and reliable measurement

However, this can only be done when all the security conditions are met. “The safety issue is major in this type of device” confirms Kevin Hertricht, “the decision to favour this or that type of braking is taken to the degree and can have significant consequences in the event of an error, to ensure the safety of the driver, the technology of our sensor must therefore be both reliable and extremely precise.” To do this, the sensor couples a mechanical interface to a so-called rotary measurement technology: “We propose a new detection technology,” explains Kevin Hertricht, “it is non-contact between the mechanical lever and the cell, and the measurement it takes is called rotary because it allows us to know the exact position of the rotary element in relation to the static element.” In addition, the sensor incorporates a spring that suppresses hysteresis effects that occur when there is “slack” in the mechanical connections and that can distort the measurements.

EFI Automotive’s safety expertise

In the automotive industry, safety is regulated by ISO 26262 and the level of requirements by ASIL (Automotive Safety Integrity Level) ranging from A to D. “EFI Automotive has recognized expertise in ASIL,” recalls Kevin Hertrich, “with this brake pedal sensor, customer demand is in ASIL C but we have already responded to calls for tenders for ASIL D level sensors.” Initiated as a project in 2017, serial production of these sensors is effective since the beginning of 2019. EFI Automotive sensors can be adapted to all types of crankset and vehicles. At present, production is mainly for PSA Group hybrid and electric vehicles. Ultimately, the volumes should be around 800,000 parts per year, all of which will be produced at the Beynost (Ain) site.