Brakes are the most important part of any automobile, which performs the function of stopping or slowing down the vehicle. The vehicle hydraulic brake systems should be developed with the purpose of ensuring the safety of passengers. For example, the pedal force required to apply the brakes must be strong enough to stop the vehicle but not so powerful that the vehicle comes to a screeching stop, which could expose the passengers to danger. Therefore, an automotive brake system should be thoroughly tested during production to ensure that it meets the required specification
For smooth and controlled braking, it is necessary to verify the performance of the hydraulic brake system and examine the relationship between the pedal force applied by the driver to the generated braking pressure. The pressures generated in the brake system can be easily measured with a differential pressure transducer in the hydraulic brake test setup.
A hydraulic brake system includes a master cylinder, wheel cylinders, hoses and brake fluid. The fluid is used as a medium to transmit mechanical force from the brake pedal to the wheel cylinders that apply pressure to the brake shoes and eventually stop the wheels from moving.
To stop the vehicle, the driver applies force to the brake pedal that moves forward and activates the hydraulic master cylinder. This action generates sufficient hydraulic pressure which is transmitted through brake fluid to the brake cylinders on each of the wheel brakes to clamp the spinning rotor. It means a sufficient amount of force needs to be applied on the pedal to generate enough braking power to stop the vehicle smoothly.
Therefore, the relation between pedal force to braking pressure is a crucial factor in automotive brake testing. If the driver applies excessive force on the pedal to stop the vehicle, it can cause premature component fatigue or even make driving unsafe. In addition, it will lead to an abrupt or screeching stop. To avoid these conditions, automotive manufacturers should test the prototype vehicle during the development stage to verify braking performance.
As shown in the figure above, the hydraulic brake test setup is equipped with a Validyne P55 differential pressure transducer to measure the hydraulic pressure generated by the master cylinder. The sensor can be easily connected to the hydraulic system due to its compact size. A load cell is also connected to the brake pedal to measure the force by the driver on the pedal.
This rugged differential pressure sensor is highly suitable for automotive brake testing due to its small displacement volume. It means that the sensor does not interfere with the operation of the brake system. It also has extreme resistance to shock and vibration making it suitable to be installed on the vehicle under various conditions on the test track.
The P55 pressure sensor comes with a variety of sensor O-ring seals to ensure compatibility with a wide range of brake fluids. It can output data via USB to interface directly with the computer system or CANbus output for easy connection with the automotive measurement system
Moreover, the differential pressure measured by the pressure transducer along with the load cell output is recorded with a data acquisition system. The data can be measured and recorded under various test track environments to gain valuable insight into the performance of the braking system.
Subscribe to our newsletter for more technical content.
